REVIEW published: 06 July 2022 doi: 10.3389/fimmu.2022.904497 CAR T-Cell Therapy Predictive Response Markers in Diffuse Large B-Cell Lymphoma and Therapeutic Options After CART19 Failure Ana Carolina Caballero 1,2,3,4, Laura Escribà-Garcia 1,2,3, Carmen Alvarez-Fernández 1,2,3 and Javier Briones 1,2,3,4* 1 Hematology Service, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain, 2 Laboratory of Experimental Hematology-IIB, Institut Recerca Hospital de la Santa Creu i Sant Pau, Barcelona, Spain, 3 Campus Sant Pau, Josep Carreras Leukemia Research Institute, Barcelona, Spain, 4 Autonomous University of Barcelona, Barcelona, Spain Immunotherapy with T cells genetically modified with chimeric antigen receptors (CARs) has shown significant clinical efficacy in patients with relapsed/refractory B-cell lymphoma. Nevertheless, more than 50% of treated patients do not benefit from such therapy due to either absence of response or further relapse. Elucidation of clinical and biological features that would predict clinical response to CART19 therapy is of paramount importance and eventually may allow for selection of those patients with greater chances Edited by: Enrico Derenzini, of response. In the last 5 years, significant clinical experience has been obtained in the University of Milan, Italy treatment of diffuse large B-cell lymphoma (DLBCL) patients with CAR19 T cells, and Reviewed by: major advances have been made on the understanding of CART19 efficacy mechanisms. Leopold Sellner, Heidelberg University Hospital, In this review, we discuss clinical and tumor features associated with response to CART19 Germany in DLBCL patients as well as the impact of biological features of the infusion CART19 Utpal Dave, product on the clinical response. Prognosis of DLBCL patients that fail CART19 is poor Indiana University, United States and therapeutic approaches with new drugs are also discussed. *Correspondence: Javier Briones Keywords: CAR-T, DLBCL, lymphoma, antibodies, bispecific jbriones@santpau.cat Specialty section: This article was submitted to INTRODUCTION Alloimmunity and Transplantation, a section of the journal B-cell non-Hodgkin lymphomas (B-NHL) comprised some 544,000 new cases/year and caused Frontiers in Immunology 260,000 deaths worldwide in 2020 (1). Diffuse large B-cell lymphoma (DLBCL) is the most common Received: 25 March 2022 subtype, accounting for 30%–40% of all newly diagnosed lymphomas in the world. DLBCL has an Accepted: 07 June 2022 aggressive behavior and needs rapid treatment (2). First line of treatment is usually composed of Published: 06 July 2022 repeated cycles of chemoimmunotherapy with rituximab combined with cyclophosphamide (Cy), Citation: doxorubicin, vincristine, and prednisone (R-CHOP) that allows to achieve long-term disease Caballero AC, Escribà-Garcia L, remissions in 60% of cases (2, 3). Forty percent remains unresponsive, either due to primary Alvarez-Fernández C and Briones J refractoriness (10%–15%) or relapse after having achieved an initial complete response (20%– (2022) CAR T-Cell Therapy Predictive 25%) (4). Response Markers in Diffuse Large B- Cell Lymphoma and Therapeutic Overall survival (OS) in relapsed or refractory (R/R) subgroup patients is poor. High-dose Options After CART19 Failure. chemotherapy followed by autologous stem cell transplantation (ASCT) is the standard of care Front. Immunol. 13:904497. (SOC) in this situation for patients considered suitable for that treatment. About a half of R/R doi: 10.3389/fimmu.2022.904497 DLBCL patients are not eligible for intensive approach due to advanced age or comorbidities. There Frontiers in Immunology | www.frontiersin.org 1 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure is no salvage regimen that has proven to be superior with overall antitumor effect, anergy, and lack of expansion (9, 10). In late response rates (ORRs) of 40%–50% and only ~20% of complete 1990s, second-generation CARs were built by adding a responses (5). This means that only up to 50% of patients who costimulatory domain (CD28) to the initial first-generation are potentially candidates for intensive treatment would reach a CAR construct (Figure 1). These changes were based on the required response to proceed to ASCT (2, 4–6). Among patients knowledge of TCR function to optimize in vivo expansion of who received ASCT, less than 50% would be disease-free after 5 activated T cells (11). Second-generation CAR directed against years (5). Refractory patients, defined as DLBCL that did not CD19 (CAR19) was shown to be effective in B acute achieve objective response or relapsed ≤12 months after lymphoblastic leukemia (B-ALL) animal models (12). Early treatment, remain the greatest challenge. For these patients, studies with CAR20 T cells showed limited efficacy in patients current salvage treatments yield ORR approximately 26% with with B-NHL, presumably because they were done with a first- less than 10% CRs, and their median OS was reported to be as generation CAR (13). short as 6.3 months in some studies (4). Finally, CAR T cells moved into the clinical setting when The poor outcomes shown by patients with R/R DLBCL treating a patient with refractory follicular lymphoma who constitute an unmet medical need and have allowed adoptive reached partial response (PR) after CART19 therapy (14). cell therapy (ACT) to change the paradigm of lymphoma Then, a few academic studies published their earliest clinical treatment. Initially, ACT sought to sensitize and expand experiences with CAR19 T cells, paving the way for the tumor-reactive T-cell in vivo and direct isolation of tumor- development of CART19 clinical trials for patients with B- infiltrating lymphocytes (TILs) has been tested in multiple NHL (15–21). solid tumor studies with some durable responses, particularly in melanoma (7). ACT has evolved to increase efficacy and specificity. In late 1980s, first-generation chimeric antigen receptors (CARs) were described. Initially, they were OVERVIEW OF CLINICAL TRIALS IN constructed by fusing T-cell receptor (TCR) constant domain DLBCL WITH CLINICALLY APPROVED (segments a or b chains) and the variable region of an antibody, CART19 both the heavy chain and the light chain (8). Next, recognition domain was simplified into a single-chain peptide structure Clinical trials with CART19 therapy have shown great efficacy in derived from heavy and light chain variable region of a specific heavily pretreated patients with DLBCL, high-grade B immunoglobulin (scFv). The scFv was fused with z chain of the lymphoma, and primary mediastinal B-cell lymphoma TCR CD3 complex, and thus a first-generation CAR was (PMBCL). Outstanding results in academic studies led to the generated. CAR T cells containing CD3z demonstrated clinical development and subsequent approval by regulatory antitumor activity in vitro but exhibited limited in vivo agencies of three different CAR19 T-cell products (Figure 1). FIGURE 1 | Illustration of the evolution of chimeric receptors design. Fragments from the native TCR-CD3 complex and antibodies were joined into fusion proteins that were improved to reach the basic structure of the second-generation CARs, which were successfully brought to the clinic. At the bottom, the figure shows the critical differences between the three FDA-approved second-generation CAR constructs. Frontiers in Immunology | www.frontiersin.org 2 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure Axicabtagene ciloleucel (Axi-cel, Yescarta) is a CAR19 T-cell 4-1BB (CD137) and an additional sequence encoding a truncated product originally designed by researchers at the National Cancer epidermal growth factor receptor (EGFRt) to guarantee Institute (15, 16, 22) and later developed by Kite-Gilead. Autologous identification of transduced T cells. The transduced CD4+ and peripheral blood mononuclear cells (PBMCs) from fresh CD8+ T-cell fractions are mixed in a 1:1 ratio to obtain the final leukapheresis are the starting material. PBMCs are genetically formulation (20, 21). Liso-cel is approved for the treatment of R/ modified by gamma retroviral vector to express a CAR. Axi-cel R DLBCL, PMBCL, and FL grade 3B (FL3B) after at least two uses a second-generation CAR with anti-CD19 scFv as recognition prior therapies. TRANSCEND NHL001 study led to FDA domain, CD3 z as activation, and CD28 as costimulation domain. approval for Liso-cel. It was a phase 1/2 clinical trial and Axi-cel has been approved to treat patients with R/R DLBCL, included 269 patients (173 DLBCL, 78 DLBCL transformed PMBCL, or DLBCL transformed from follicular lymphoma (FL), from indolent lymphoma, and 15 PMBCL). Median age was 63 R/R to at least two previous lines of treatment. The approval was years (range: 54–70), 67% of patients had refractory disease, and derived from the results of ZUMA-1, a phase 1/2 clinical trial that 33% patients had previously received ASCT. Bridging therapy treated 101 patients (77 with DLBCL and 24 with PMBCL) with a was administered to 59% of patients. All patients received LD single dose of 2 × 106 CAR19+T cells/kg. All patients received regimen with Cy 300 mg/m2/day and Flu 30 mg/m2/day for 3 lymphodepletion (LD) regimen with Cy 500 mg/m2/day, and days before infusion. CRS was observed in 42% of cases, but only fludarabine (Flu) 30 mg/m2/day for 3 days before infusion. The 2% developed severe CRS (≥3 grade). ICANS was detected in median age of treated patients was 58 years (range: 23–76). Most of 30% of cases and 10% of them were higher than grade 3. Phase 1 them had stage III or IV (85%), primary refractory disease comprised sequentially evaluated three doses: 50 × 106 CAR19+ (dose 1), 2% and another 77% was refractory to second line or subsequent. 100 × 106 CAR19+ (dose 2) and 150 × 106 CAR19+ (dose 3). Dose Twenty-one percent of patients had history of recurrent disease after 2 (100 × 106 CAR19+) was selected for phase 2 to test efficacy. ASCT. Bridging therapy before CART19 infusion was not allowed. The ORR was 73% with 53% of CRs. PFS at 12 months was 48% Cytokine release syndrome (CRS) occurred in 93% of patients and with an OS of 58% for the overall patient population (25). 13% of them were grade 3 or higher. Neurologic events (ICANS) In summary, CAR T-cell therapy progressively evolved in the occurred in 64% of cases and 23% were grade ≥ 3. ORR was 82% with last 2 decades to finally breakthrough the SOC treatment for R/R 54% CRs. The median duration of response (DOR) was 11.1 months, DLBCL and other B-cell neoplasms. A few academic research and after a median follow-up of 27 months, the two-year progression- groups and pharmaceutical companies brought their own CAR19 free survival (PFS) was 41% and OS was 50% (23). T-cell product into the practice through clinical trials, which were Tisagenlecleucel (Tisa-cel, Kymriah) is a CAR19 T-cell product different in design, but led to approval and commercialization of all derived from studies at the University of Pennsylvania followed by three products: Axi-cel, Tisa-cel, and Liso-cel. Main differences in clinical development by Novartis (17–19). T cells are isolated from relevant features among these pivotal clinical trials are summarized autologous cryopreserved leukapheresis, as starting material. in Table 1. Different primary endpoints, evaluations, and statistical Isolated T cells are transduced with a lentiviral vector encoding a analysis in these studies were added to distinct intrinsic features of second-generation CAR costimulated with 4-1BB (CD137), the CAR19 T-cell product: starting material, dose, T-cell targeting CD19 and having CD3 z as activation domain. Tisa-cel composition, culture conditions, and constructs design. Despite has been approved for the treatment of R/R DLBCL after at least this, surprisingly similar efficacy was seen among all three two previous lines of treatment. JULIET, a phase 2 clinical trial, was products with remissions approximately 50% in this previously the pivotal study and included 111 patients (88 DLBCL and 21 incurable patient population, although differences in toxicity were DLBCL transformed from FL) who were treated with a single noticed in the clinical trials. infusion of Tisa-cel. The median dose administered was 3 × 108 Although CART19 therapy has been successful in treating CAR19+T cells (range: 0.6–6 × 108). Cy 250 mg/m2/day and Flu 25 and probably curing some patients with R/R DLBCL, the fact is mg/m2/day for 3 days before infusion was used as LD regimen. The that more than half of them remain refractory or relapse after median age of the included patients was 56 years (range: 22–76), CART19. There is room for improvement and the treatment of stage III or IV was in 76% of cases, 55% of patients were refractory multirefractory patients is increasingly challenging. In-depth to previous line, and 49% had received ASCT. Most of the patients knowledge of current outcomes and associated clinical or (92%) received bridging therapy before CART19 administration. biological characteristics of patients and product properties CRS was observed in 56% of patients, but only 22% of grade ≥3 was that influence therapy success is essential to guide treatment, detected. ICANS was less common (21%) and less severe (12% modulate expectations, and decide on the most effective salvage grade ≥3). ORR was 52% with 40% CR. PFS at 12 months was 35% therapy after CART19 failure. for all patients (24). Lisocabtagene maraleucel (Liso-cel) is a second-generation CAR19 T-cell product originally designed and formulated by investigators at the Fred Hutchinson Cancer Research Center CLINICAL OUTCOME AFTER CART19 and then continued by Juno and Bristol-Myers Squibb. Liso-cel is THERAPY IS INFLUENCED BY PATIENT generated from fresh autologous leukapheresis. CD4+ and CD8+ AND DISEASE FEATURES T cells are selected and separated into two different fractions to be cultured in parallel and are genetically modified by lentiviral All published data agree that CART19 therapy improved R/R vector encoding a second-generation CAR19 costimulated with DLBCL clinical outcomes and OS; however, identifying the Frontiers in Immunology | www.frontiersin.org 3 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure TABLE 1 | Pivotal Clinical Trials with CART19 Therapy for B-NHL: Comparison of Relevant Features Among Studies. Clinical trial ZUMA-1 JULIET Transcend Product name Axicabtagene ciloleucel Tisagenlecleucel Lisocabtagene maraleucel Co-stimulatory domain CD28 4-1BB 4-1BB Leukapheresis Fresh Cryopreserved Fresh Starting material PBMCs Selected T cells Sorted CD4+ and CD8+ fractions Transduction Retroviral Lentiviral Lentiviral Final composition Bulk T cells Bulk T cells Defined ratio CD4+:CD8+ 1:1 Patients enrolled, n 111 165 344 Infused patients, n 101 111 269 Study population DLBCL DLBCL DLBCL PMBCL tFL DLBCL transformed from indolent lymphoma tFL PMBCL FL grade 3B Bridging therapy (% patients) Not allowed Allowed (92%) Allowed (59%) Lymphodepleting therapy Cy 500 mg/m2/day + Flu 30 mg/m2/ Cy 250 mg/m2/day + Flu 25 mg/m2/ Cy 500 mg/m2/day + Flu 30 mg/m2/day day day 3 days 3 days 3 days Stage III/IV 85% 76% NR >3 prior lines 69% 52% 51% Refractory disease 77% 55% 67% Previous ASCT 21% 49% 33% Cell origin Germinal center B-cell–like 49% 57% NR subtype Activated B-cell–like subtype 17% 41% NR High-grade B-cell lymphoma NR 27% 13% Dose 2 × 106 CAR T cells/kg Median dose: 3 × 108 CAR T cells/kg 1 × 108 CAR T cells (0.1 × 108–6 × 108) (50 × 106 CD8+ + 50 × 106 CD4+ CAR T cells) DLBCL, diffuse large B cell lymphoma; PMBCL, primary mediastinal B cell lymphoma; tFL, transformed follicular lymphoma; NR, not reported. subgroup of patients who would certainly benefit from CART19 infusion were also associated to longer PFS (26–28). Finally, a remains a challenge. Patient selection criteria in clinical trials are recent study that evaluated international prognostic index (IPI) us ua lly hom ogeneous and comor bid ities a re often and age-adjusted IPI, two widely used indices to identify DLBCL underrepresented, making it difficult to identify differential patients with higher probability of survival following frontline baseline characteristics that may influence clinical outcome. Thus, therapy, found an association with them and PFS after CART19 the pivotal studies of Tisa-cel and Axi-cel agreed that there were no treatment (29). clinical covariates predictive of efficacy (23, 24). In contrast, Liso-cel Several tumor-related prognosis factors routinely analyzed in pivotal trial, which was the largest and the most variable in terms of DLBCL (i.e., cell of origin, myc, and bcl-2 rearrangements) did diagnoses (including R/R DLBCL, R/R PMBCL, transformed not prove to be informative of sensitivity to CART19 therapy. DLBCL arising from indolent histologies other than FL and Preliminary studies on the role of such tumor features in patients FL3B), showed that DOR and PFS in patients with PMBCL and treated with CART19 in different trials did not find a strong DLBCL transformed from FL were longer than for other subtypes impact on CART19 tumor resistance, with comparable clinical and that bridging therapy was associated with lower efficacy among responses observed across all these mentioned subgroups (24, included patients, likely reflecting a selection bias (25). 30). P53 alterations are described markers of poor outcome and Data from a retrospective study, which analyzed baseline treatment resistance in DLBCL (31). A recent study found that patient characteristics to evaluate whether classical prognosis DLBCL patients with tumors harboring P53 alterations had factors could distinguish patients most likely to achieve disease lower responses and survival after CART19 therapies, remission, showed associations between achieving CR at 12 particularly following a 4-1BB costimulated second-generation months after Axi-cel treatment and no need for bridging CART19 (32). DLBCLs with P53 were found to have more therapy (26). The need for bridging therapy reflects higher frequently downregulation of genes related to interferon tumor burden (TB) or more rapidly progressive disease and signaling pathway, which may contribute to further inhibition thus emerges as a negative prognostic feature. Other patient- of CAR19 T cells. However, this is in contrast to the findings of a dependent features, such as age (≥60years), ECOG 0/1, and previous study showing a correlation with a high interferon- normal lactate dehydrogenase (LDH) at the time of related gene expression and lack of durable response after Axi-cel conditioning, were also described to be associated to CRs after treatment (33). Further studies are needed to establish the role of Axi-cel treatment. These are important findings considering that this critical signaling pathway on the resistance of DLBCL to attaining CR is the most important goal after treatment of CART19 therapy. aggressive lymphomas (26). Performance status, no need for Even though some studies conclude that distinct LD regimens bridging therapy, and normal LDH values before CAR19 T-cell do not affect clinical outcomes (34), it has been shown that LD Frontiers in Immunology | www.frontiersin.org 4 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure plays a role in both T-cell kinetics of expansion and clinical higher in responders compared to non-responders (25). outcome in B-cell malignancies. Elimination of regulatory T cells Besides, further analyses revealed the value of estimating the (Tregs) and improved function of transferred T cells by increasing number of CAR19 T cells per unit of blood volume, which seems the availability of homeostatic cytokines are among the proposed to be even more informative than the number of CAR19 gene mechanisms that explain the positive impact of LD on the copies per microgram of host DNA, to predict response (41). efficacy of adoptive therapy. Interleukin-7 (IL-7) and Overall, data from different clinical studies demonstrate that a interleukin-15 (IL-15) have supporting roles in the survival high-peak expansion of CAR19 T cells in peripheral blood and proliferation of adoptively transferred T cells and have correlates with a durable response in B-cell neoplasms (25, 30, been proved to be critical to enhance adoptive T-cell antitumor 44, 45). effect in vivo (35). Flu combined with Cy represents the most In addition to the achievement of a favorable cytokine profile frequently LD regimen used and enhances CD4+ and CD8+ in the host, antigen exposure on tumor cells can also modulate proliferation and persistence of 41BB-CAR19 T cells in R/R ALL CAR T-cell expansion. As a proof of concept, a superior patients (36). Furthermore, the intensity of the LD regimen may expansion of CAR19 T cells has been detected in patients with positively impact on the outcome after CART therapy, as it has high TB in R/R B-ALL. However, comparison between these been shown after adoptive therapy of TILs (37). Elevated levels of studies is hampered by the fact that the definition of high TB was IL-7 and monocyte chemoattractant protein-1 (MCP-1) were highly heterogeneous (36, 46–48). Although similar patterns of associated with superior expansion and better PFS in patients CAR19 T cells increase and biexponential decline were observed with B-NHL treated with CART19 and, interestingly, this in DLBCL and B-ALL, CAR19 T-cell peak in peripheral blood is favorable cytokine profile was found more frequently in those lower in DLBCL and a number of studies showed no apparent patients receiving higher doses of that combo (28). In addition, relationship between TB and expansion (24, 43, 49). In line with lymphoma patients who achieve CR developed a greater increase this, there was a remarkable finding of sustained CAR19 T-cell of serum IL-15 levels after Flu/Cy LD and a greater area under expansion and long-term CR in DLBCL patients treated with the curve (AUC) of CAR19 T cells up to day +14 after infusion CART19 and without detectable disease (according to FDG- (38). Recent studies found that optimizing Flu exposure may PET/CT) at the time of infusion (50). Furthermore, the limited have a relevant impact in PFS and OS of B-ALL R/R patients clinical data available indicates that patients with low intensity of after CART19 (39, 40). Examination of cumulative Flu exposure CD19 expression in tumor samples did not have inferior suggest that an AUC ≥ 14 mg*h/L is associated with a lower responses (24, 30, 43). proportion of CD19+ relapses, lower cumulative incidence of B- Another feature associated to CART19 efficacy is tumor cell recovery after CART19, and higher CAR19 T-cell expansion volume. DLBCL patients with bulky disease have inferior (39). In agreement with these data, another study in B-ALL clinical outcomes. Recently, measurements of pretreatment found that a subop tima l Flu exposure (defined as FDG-PET/CT images have allowed to estimate TB more AUC ≤ 13.8 mg*h/L) was associated with increased risk of accurately and a greater metabolic tumor volume (MTV) has relapse and loss of B-cell aplasia. Furthermore, Flu exposure been proposed as a new predictor of lower PFS and OS. However, was noted to affect OS in patients with high pre-infusion TB (40). heterogeneous cutoffs for high or low TB were used in these These data indicate that adjustment of Flu dose may have a studies and hence formal clinical validation is lacking (51–53). relevant impact on CART19 efficacy in patients with B-ALL, Retrospective studies tried to extend baseline MTV evaluation to which should be prospectively studied in patients with DLBCL. DLBCL patients treated with CAR19 T cells and concluded that Overall, these data suggest the environment (influenced by patients with a low MTV have superior OS and PFS (41, 42, 54, conditioning) into which CAR T cells enter upon infusion and 55). Preliminary data suggest that MTV and average modulate CAR T-cell functionality, which may translate into standardized uptake value evaluated early after therapy are improved treatment outcomes. Other markers related to a pro- independent risk factors associated to OS and PFS (55). inflammatory setting have been shown to have an impact on Nonetheless, other studies found discrepant results with no clinical results. Thus, elevated LDH and IL-6 before treatment significant differences in clinical outcome according to MTV have been associated to lower durable response rates, while high (56), highlighting the differences in type of measurement, pretreatment CRP, ferritin, and LDH levels have been associated methodological aspects, and definitions. Overall, future with lower CAR19 T-cell expansion (41, 42). research should also include tumor debulking prior to CART Higher peak and longer persistence of CAR19 T cells were therapy, as current data suggests that patients with a lower TB at shown to determine a better PFS in R/R ALL patients (36). the time of CAR19 T-cell infusion are more likely to be Persistence of CAR19 T cells evaluated by flow cytometry was cured (57). found to be longer in patients with DLBCL R/R who achieved New diagnostic techniques that emerge as promising response after treatment with Tisa-cel (43). Greater CAR19 T- predictors of relapse in DLBCL converge with the introduction cell peak and AUC in the first 28 days after infusion have been of new therapies. Circulating tumor DNA (ctDNA), released reported to be associated with objective and durable response in from apoptotic and/or necrotic tumor cells, is an emerging lymphoma patients treated with Axi-cel (30, 41, 44). prognostic biomarker for lymphoma. Next-generation Furthermore, the Liso-cel pivotal clinical trial evidenced a sequencing-based assays that utilize immunoglobulin gene V median maximum expansion (Cmax) and AUC significantly (D)J rearrangements as a marker of clonality for detecting cancer Frontiers in Immunology | www.frontiersin.org 5 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure cells have been applied to patients with lymphoid malignancies, It is well established that cellular CART products infused into and surveillance ctDNA has been shown to identify patients at patients are quite heterogeneous, related to T-cell subset risk of relapse before clinical evidence of disease after first-line composition as well as exhaustion, all of these being tumor treatment (58–60). In relation to this, a prospective study dependent (i.e., T cells from CLL patients may be more explored the prognostic value of ctDNA after Axi-cel differentiated and exhausted than in other B-NHL). treatment. In this study, high ctDNA concentrations before Collectively, these differences may contribute significantly to treatment were associated with progression after Axi-cel the efficacy of the CART19 therapy. Furthermore, patients with infusion, while non-detectable ctDNA at day 28 after treatment DLBCL have substantial differences in their frequencies of was correlated with longer PFS (61). In addition, preliminary peripheral blood T-cell subsets (naïve, TCM, or TEM) (20, 21), data on profiling genomic alterations in tumor DLBCL samples due to factors such as age and chemotherapy regimens received suggest that the median numbers of plasma ctDNA mutations (71), and these variabilities have an impact on the cell quality of after CART19 treatment in patients who remained in CR and the apheresis products used for CAR T-cell manufacturing. patients who relapse were extremely different (62). Taken Hence, use of appropriate in vitro culture methods that together, ctDNA clonotype and tumor mutations surveillance promote enrichment of TSCM and TCM subsets within the can be useful to determine prognosis and even detect specific CART product would potentially enhance their clinical targets for designing treatment strategies after CART19 failure. efficacy. Preclinical studies in xenogeneic animal models of B- cell lymphoma have shown that CART19 cells manufactured from CD4 and CD8 TN and TCM cells have improved antitumor effect compared with those CART derived from more CAR T-CELL PRODUCT COMPOSITION: differentiated T-cell subsets (20, 72). In line with this data, THE IMPORTANCE OF LESS studies in xenogeneic human lymphoma models have shown DIFFERENTIATED MEMORY T CELLS that CART products with a high proportion of TSCM cells have enhanced in vivo anti-lymphoma effect compared with those Early-Memory T-Cell Subsets and with a lower proportion of TSCM (73), highlighting the concept CART19 Efficacy that CART products enriched with less differentiated memory T Following antigenic stimulation, “naïve” T cells (TN) proliferate cells could contribute to improved clinical efficacy. and differentiate into memory T cells (TM) and effector T cells Development of CART products manufactured from TN cells (TEF). TM lymphocytes play a fundamental role in the immune resulting in high proportion of TSCM and TCM cells has been response against cancer. In humans, the TM cell population is hampered by the absence of methods to isolate TN cells under heterogeneous with respect to phenotype and function but can be clinical-grade manufacturing (GMP) conditions. However, recent divided into two groups (63): central memory T cells (TCM), technical advances using culture conditions with IL-7/IL-15 and which express CD45R0, CD62L, and CCR7; and effector memory the addition of IL-21 may enhance the enrichment for TSCM cells T cells (TEM) lacking CD62L and CCR7. Several studies in animal in the final CART product (74–76), which can be further increased models of cancer have shown that TCM cells have a superior with the addition of drugs blocking T-cell differentiation, such as antitumor effect than differentiated TEM and TEF cells (64). A glycogen synthase-3 inhibitors (77). Nevertheless, robust clinical- subtype of memory T cells, the memory stem T lymphocytes grade protocols for generating TSCM-enriched CART products (TSCM), has been identified in humans with distinct gene have not been developed so far. Recently, a few CART19 clinical expression and functional attributes to other T-cell subsets (65, trials for DLBCL have been conducted in which CART products 66). These cells represent 2%–3% of the entire T-cell population were manufactured from CD62L+ isolated T cells to generate in peripheral blood from healthy individuals. TSCM cells are cellular products enriched for TCM cells (21, 78); however, due to characterized by expressing naïve and memory markers such as prolonged culture conditions, enrichment for TSCM and TCM CD45RA, CD62L, and CCR7 but, unlike TN cells, they express subsets in the infused product could not be demonstrated. The high levels of CD95, CXCR3, CD58, and IL2Rb. (65, 67) TSCM clinical impact of this strategy is being tested in recent CART19 cells have the ability to self-renew and to generate all the progeny clinical trials with very short culture or following isolation of TN- of memory (TCM and TEM) and effector (TEF) T cells (66, 68). TCM T cells for CART manufacturing, in patients with DLBCL Compared to central memory and effector T cells, this unique (NCT02153580). Combinatorial approaches like CD62L + population has a higher proliferative and persistence capacity in selection with the use of cytokines promoting TSCM generation vivo and, importantly, a superior antitumor effect in animal (e.g., IL-15 and IL-21) during the ex vivo expansion could further models of cancer (69); this attribute also holds true for those improve the enrichment of TSCM and TCM CAR T cells, and this T SCM gene-modified with an antigen-specific CAR; thus, strategy is already being developed in a clinical trial of CART19 for adoptive transfers of sorted memory T-cell subsets (e.g., TSCM, patients with DLBCL and others B-cell NHL lymphoma TCM, and TEM) transduced with a mesothelin-redirected CAR (NCT04653649). Overall, preclinical studies convincingly into a xenogeneic model of human mesothelioma demonstrated demonstrated that in vivo administration of less-differentiated a superior antitumor effect of the TSCM subset, which was also memory T cells results in enhanced engraftment, expansion, associated to enhanced proliferative capacity and persistence of and persistence, which are features required for clinical CAR T cells (65, 70). efficacy of CART therapy for B-cell malignancies (16, 24, 25, Frontiers in Immunology | www.frontiersin.org 6 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure 41). Remarkably, these findings are being replicated in clinical (23, 24, 34, 82), although a very low incidence of severe studies of patients with B-cell malignancies treated with CART19. complications (CRS and ICANS) was noticed. Since no Preliminary studies in 14 patients with B-cell lymphoma comparisons with other manufactured CART19 products have treated with CAR19 T cells have shown the existence of an been done, it remains to be seen if this approach results in association between the presence of TSCM (> 5% of total T cells) improved efficacy and/or toxicity in patients with DLBCL. in the infusion product and the in vivo expansion (79). The generation of products with these features was mostly obtained Pharmacological Intervention to Enhance by substituting IL-7 and IL-15 combination with IL-2 as growth Generation of Memory CART19 Cells factors in the culture. Because those patients did not receive As CART19 therapy needs T-cell expansion and appropriate lymphodepleting chemotherapy, a correlation with clinical engraftment, pharmacologic interventions to enhance these response could not be proven; however, this was the first properties have been studied. Ibrutinib, a first-in-class clinical study showing a clear association between the infusion irreversible inhibitor of Bruton tyrosine kinase, has shown to of less differentiated memory CAR19 T cells and expansion, one improve several T-cell effector functions (i.e., activation, INFg of the most clinically relevant features required to obtain a secretion). Studies in patients with chronic lymphocytic complete remission (23–25). Further confirmation of the leukemia (CLL) receiving CART19 have shown that prolonged clinical impact of administration of CART memory T cells ibrutinib treatment contributes to decreased expression of T-cell comes from a clinical study in patients with CLL treated with inhibitory molecules (PD-1 and CD200) with reversion of CART19 (80). Patients with complete response exhibited functional status of CAR19 T cells and enhanced in vivo dramatic expansion of CAR19 T cells and this was associated proliferation (83, 84). These data prompted to evaluate with the presence of TSCM cells in the leukapheresis product. ibrutinib administration before leukapheresis and concurrent Moreover, clinical responses were seen mostly in those patients with CART19 therapy. No differences in T-cell subset receiving CART19 products enriched in CD8+ CD27+ PD-1- T composition were described in these studies (83, 84), but cells with a high expression of IL-6R and STAT-3-related preliminary data from a phase 1 clinical trial in patients with cytokine secretion such as IL-21, which are closely related to R/R CLL and indolent B-NHL (NCT00466531) reported TSCM. The correlation between presence of memory T cells and significantly greater ex vivo expansion and proportions of clinical response to CAR-T therapy was further demonstrated in CAR19 T cells expressing CD62L and CD127 in patients on a very recent study with DLBCL patients treated with Axi-cel ibrutinib at the time of leukapheresis (n = 5) (85). Further studies (81). Here, the infusion products of 24 patients with B-cell are needed to confirm these findings as well as if the effect of lymphoma (mostly DLBCL) were analyzed for gene expression ibrutinib on CAR19 T cells is seen also in DLBCL patients. using a transcriptome profiling approach. Patients with CRs and CAR T-cell expansion, differentiation, and persistence results durable responses received CART19 products highly enriched from the integration of signals arising from multiple receptors— (3-fold higher) in CCR7 + CD27+ memory CD8 + T cells these signals converge to activate two major signal transduction compared with those patients with progressive disease. networks within T cells: the MAPK and PI3K/AKT/mTOR Further data on the relevance of infusion product T-cell pathways (86). Activation of phosphoinositide 3-kinase (PI3K) fitness come from a recent analysis of DLBCL patients treated has a critical effect on T-cell proliferation, survival, and effector/ with Axi-cel (41). In this study, the number of infused CD45RA+ memory subset formation. PI3Kd promotes mTOR signaling and CCR7+ (i.e., TN and TSCM cells) significantly correlated with peak increases T-cell metabolic activity, which facilitates effector T- CAR19 T-cell levels, a lower double timing, and durable cell differentiation and function. Ex vivo pharmacologic blockade responses; interestingly, a high number of CD8+ T cells were of PI3K or AKT during CART19 manufacture contributed to needed to promote clinically meaningful responses, at least in generation of memory T cell with enhanced antitumor effect in patients with a high TB. In contrast, CART19 products enriched preclinical models (86), and this strategy has been moved to the in other T-cell subsets failing to express that phenotype clinic in patients with multiple myeloma receiving CART correlated with clinical failures, highlighting the concept that directed to the BCMA antigen (87). CAR T-cell subsets resembling TN and TSCM are the most Pharmacological modulation of CAR T cells during responsible for achieving a durable response. manufacturing is a matter of intensive research, and several drugs In addition, the variability of CD4+ and CD8+ T cells in the are being actively studied to promote CART products enriched in apheresis product results in heterogeneous CART products, with less differentiated memory T cells (i.e., BET inhibitors, c-myc a large variation in the proportion of CD4+ and CD8+ T cells, inhibitors) (88, 89). The clinical benefit of all these strategies in which may contribute to differences in clinical efficacy and/or DLBCL patients receiving CART19 remains to be proven. toxicity. In fact, preclinical studies in xenogeneic animal models of B-cell lymphoma have shown increased antitumor effect of CAR19 T cells with a defined composition of CD4:CD8 ratios (e.g., ratio 1:1). As previously mentioned, this concept has been ANTIGEN ESCAPE AND LACK OF moved to the clinic with the development of clinical trials with RESPONSE TO CART19 CART19 products defined with a CD4:CD8 ratio of 1 in patients with DLBCL (25). Clinical efficacy of this strategy in patients Antigen downregulation and antigen escape are among the main with DLBCL seems to be comparable to other CART19 studies causes of relapse in patients with B-cell malignancies after Frontiers in Immunology | www.frontiersin.org 7 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure CART19 therapy (90). Initial studies on this mechanism of CAR T-CELL FUNCTIONALITY, resistance come from clinical trials of CART19 in patients with INHIBITORY RECEPTOR EXPRESSION, B-ALL, in which, up to 30% of the relapsing patients had CD19- negative tumors. Differences in numbers of patients suffering AND CLINICAL EFFICACY CD19-negative relapses also depend on the costimulation of the CAR used (4-1BB vs. CD28), with preliminary data suggesting a The search for biological features of the infused CAR T cells higher frequency in patients receiving 4-1BB-costimulated CARs predictive of outcome is hampered by the high variability of the (91–94). products infused into the patients, regarding transduction The impact of the occurrence of CD19-negative relapses in efficiency, CAR expression, and T-cell subset composition. patients with DLBCL after CART19 therapy has been less studied, Eventually, the efficacy will depend upon the antitumor effect in part because lymph node biopsies at the time of relapse are of the infused CAR T cells and thus functional studies of the difficult to obtain and the techniques regularly used to analyze for infused CART product may reveal critical information on the CD19 expression on tumors (e.g., immunohistochemistry) are clinical efficacy. Since CART19 products are comprised of a unreliable. CD19 expression at the time of relapse has not been heterogeneous population of cells, single-cell analysis may systematically studied in pharmaceutical-sponsored clinical trials provide information on relevant cells that may be associated to of CART19 for DLBCL patients. Estimations of 20%–30% antitumor effect (100). CART19-negative relapses have been documented (90, 95) but Rossi et al. studied 22 patients with B-NHL (19 had DLBCL) these numbers may be underestimated since studies on CD19 treated with Axi-cel and their CART19 infused products, using expression were not done in most relapsed patients. A recent single cell analysis that allows the detection of more than 30 retrospective multicentric study from the US Lymphoma CAR T- proteins secreted by a single T cell (101). They found that cell Consortium reported a 30% of CD19-negative progression patients achieving a response had a proportion of CAR19 after Axi-cel treatment. Measurement of CD19 expression was T cells (up to 25% of the product) secreting at least two of assessed by flow cytometry and/or immunohistochemistry, those proteins from at least two different families (i.e., although cutoff for CD19 positivity varied widely between inflammatory, effector, chemoattractive, stimulatory, or centers (95). More accurate information on the occurrence of regulatory) compared to patients who did not respond. CD19 escape after CART19 would come from studies in DLBCL Interestingly, these cells called “polyfunctional T cells” were patients treated in academic centers with already approved CD4+ but no association with a particular phenotype could be CART19 therapies. Thus, a study undergone at Stanford demonstrated. If this study represents a measure of the product University revealed that up to 60% of DLBCL patients treated quality or specific antitumor, T-cell subsets remain an with Axi-cel had tumors at the time of relapse with diminished or unanswered question so far, as well as the reproducibility of CD19-negative expression (96). Interestingly, in this study, a these data in a larger dataset of patients (33). correlation was also found between pre-CART therapy density T-cell exhaustion has been implicated as an additional factor of expression of CD19 antigen on tumor cells, as detected by that limits the efficacy of CART therapy (102). The presence of sensitive flow cytometry, and outcome. Investigators set up a exhausted CAR T cells is characterized by dysfunctional features threshold limit for defining low versus high expression of CD19 such as reduced cytokine secretion and limited expansion molecules on tumor cells and showed an increased risk of capacity, which are markers of poor antitumor function (103). progression (50%) after Axi-cel therapy in patients with low- The analysis of exhausted CAR T cells in the infusion product is a expression CD19 DLBCL. CD19 antigen escape also happened in matter of intensive research that may allow identification of patients receiving a bispecific CART. In a small study with an in- patients who eventually do not benefit from this therapy. Thus, house developed tandem CD19/CD22 4-1BB-z CART for DLBCL CART19 cells expressing PD-1 combined with either TIM-3 or (n=21), 4 out of 14 patients had CD19-negative tumors at LAG-3 were found in high proportion in infused products of relapsing while preserving CD22 antigen expression (96). It CLL patients who failed to respond compared with lower remains to be seen if other strategies targeting simultaneously frequencies in those who attained a CR (80). Recent studies in CD19 combined with other B-cell antigens such as CD20 offer DLBCL patients treated with Axi-cel showed an association additional advantage related to efficacy and overcome antigen between lack of response and infusion of CART19 products escape (97). Mechanisms explaining CD19 escape include antigen with high proportion of CD8+ CAR19 T cells expressing TIM-3 loss due to splice variants that specifically lacks the exon and LAG-3 (81). A gene-expression signature in the infused containing the CD19 extracellular epitope recognized by all product characterized by high expression of genes related to three FDA-approved CART19 used in the clinic (98). exhaustion and activation (e.g., LAG-3, BATF transcription Alternatively, CD19 variants that lack the transmembrane factor, inhibitor of DNA binding 2 -ID2-, but not PD-1) was domain may also occur and therefore loss of surface expression. found in products infused to patients that failed to achieve a Expression of the CAR on the tumor B cell and interaction with molecular response by assessing circulating plasma-derived cell- CD19 antigen may result in masking it from recognition by the free DNA (81). Interestingly, a high proportion of LAG-3+ T cells CAR T cells and therefore conferring resistance to CART19 (99). were found in a small subset of DLBCL patients unresponsive to However, this mechanism, described in a single patient with ALL, Tisa-cel, highlighting the potential impact of this T-cell subset has not been detected in DLBCL patients so far. and clinical response (19). Frontiers in Immunology | www.frontiersin.org 8 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure Overall, these preliminary studies show that, in addition to Several preclinical and clinical studies proved that intestinal defined T-cell subsets, the presence of functional T-cell microbiota could modulate antitumor effect of chemotherapy. populations without exhaustion receptor expression characterizes Thus, Cy promoted the translocation of distinct Gram+ bacteria CART19 products with improved clinical efficacy in DLBCL (mainly Lactobacillus johnsonii and Enterococcus hirae) that patients. However, studies on the infusion of anti–PD-1 elicited effector TH17 cell responses associated with tumor antibodies either in combination or after CART19 failure have control (108). Enterococcus hirae translocated from the small not resulted in significant durable responses in patients with DLBCL intestine to secondary lymphoid organs increased intratumoral (104, 105). CD8+/Treg ratio (109). These are interesting data as Cy is used as In summary, the efficacy of CART19 therapy and subsequent conditioning treatment in CART19 therapy and can induce clinical outcome in DLBCL are influenced by patient’s features, microbial translocation that can amplify effector T-cell tumor characteristics, and the composition of the T-cell product function (110). Retrospective studies analyzed microbiome in (Figure 2). In-depth knowledge of each factor for every patient is patients receiving allogeneic hematopoietic cell transplantation highly needed to identify those patients with a high risk of (allo-HSCT) and found significant differences from healthy treatment failure. volunteers. Profiling of intestinal microbiota in those patients revealed that a higher diversity of the intestinal microbiome was associated with lower graft-versus-host disease-related INFLUENCE OF GUT MICROBIOME ON mortality (111). CART19 EFFICACY A recent study investigated whether intestinal microbiome could modulate CAR19 T-cell activity and subsequent clinical The microbial cells that colonize the human body, including outcomes in patients with B-NHL and B-ALL (112). Antibiotic mucosal and skin environments, are at least as abundant as our exposure during the four-week period before CART19 treatment somatic cells and certainly contain far more genes than our was correlated with reduced survival. Specifically, exposure to human genome. Their gene diversity encodes outstanding piperacillin/tazobactam, meropenem, and imipenem/cilastatin mechanism and metabolic competences that influence their was associated with worse OS and PFS as well as higher own microbial niche, host tissue specific, and immune-cells proportion of ICANS, independently of the CART19 function (106). Ninety-nine percent of the entire microbial costimulatory domain (e.g., CD28 or 4-1BB). In addition, mass is within the gastrointestinal tract, and it exerts both local it was found that compositions of fecal samples from recipients and long-distance effects and the bacterial community varies of CART19 therapy were significantly different from healthy between luminal and mucosa-associated communities. Studies in volunteers, represented by a lower diversity. Furthermore, germ-free animals have revealed evidence for tumor-promoting they described that a higher relative abundance of selected effects of the microbiota in various organs, including the skin, microbial taxa, including Ruminococcus, Bacteroides, and colon, liver, breast, and lungs. On the other hand, intestinal Faecalibacterium, was associated with day 100 complete microbiota can modulate the antitumor response through response. These bacterial taxa and Enterococcus have been activation of innate immunity, which may convert tumor associated with improved response and reduced toxicity to tolerance into enhanced antitumor immune responses (107). immune checkpoint blockade therapy (113, 114), as well as FIGURE 2 | Summary of main factors influencing the efficacy of CART19 therapy. Frontiers in Immunology | www.frontiersin.org 9 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure immune cell dynamics after allo-HSCT (115). Further studies are dependent cell-mediated cytotoxicity and antigen-dependent needed to confirm these findings and to understand the cell-mediated phagocytosis compared with the unmodified mechanisms by which bacterial taxa and bacterial metabolites parental immunoglobulin G1 CD19 antibody (119). Antitumor influence the immune system to improve patient outcomes after activity of Tafasitamab against R/R B-NHL was investigated in a CART therapy. phase 2a study. Tafasitamab was administered as an intravenous infusion on days 1, 8, 15, and 22 of a 28-day cycle, for two cycles. Patients achieving PR or CR could continue to receive Tafasitamab until disease progression or unacceptable toxicity. TREATMENT OPTIONS AFTER Twenty-six percent of patients with R/R DLBLC responded and CART19 FAILURE 6% accomplished CR. The median PFS was 2.7 months (119). To enhance the antitumor effect, a second phase 2 trial tested a Significant numbers of R/R DLBCL patients will experience potentially synergistic combination: Tafasitamab-lenalidomide. disease progression following CART19, but little data are The combination was evaluated in R/R DLBCL patients who available on outcomes of these patients. Initial studies have were considered ineligible to receive high-dose chemotherapy reported that about 75% of DLBCL patients progressing after followed by ASCT. Median lines of treatment before CART19 would be candidates for salvage therapy, while the Tafasitamab-lenalidomide were 2 (range: 1–4). Patients remaining 25% would receive palliative treatment only (95, 116). received intravenous Tafasitamab (days 1, 8, 15, and 22) Current data show a very poor outcome for those patients simultaneously with oral lenalidomide (days 1–21) for up to 12 refractory to CART19. Thus, a recent multicenter retrospective cycles (28 days each), followed by Tafasitamab monotherapy (in study of the US Lymphoma CAR T-cell Consortium showed a patients with stable disease or better) until disease progression median PFS of 55 days from first therapy after Axi-cel failure (120). After >35 months follow-up, ORR was 57.5% including (95). Furthermore, these studies have shown that CART19- 40% of patients achieving CR. The median PFS was 11.6 months. refractory patients or those with progression within 30 days of Patients treated with CART19 were not included (121). CAR19 T-cell infusion have a dismal outcome (116). Interestingly, remission of DLBCL after CART19 was reported Nevertheless, no differences in efficacy or DOR were reported in one patient who previously failed to Tafasitamab. CD19- among different current salvage therapies post-CART19 targeted therapies could be effective despite being administered (95, 117). sequentially (122). CART19 failure represents a complex and challenging scenario, since most available salvage strategies, including Antibody-Drug Conjugates conventional and novel therapies, have been approved based Antibody-drug conjugates are mAbs conjugated to cytotoxic on clinical trials that specifically excluded patients receiving agents. This treatment modality takes advantage of the CART19 therapy. While priority should be given to inclusion antibody specificity for the target antigen and achieves of patients in clinical trials, conventional therapy may still antitumor activity through the addition of different effector provide short-term disease control in a limited number of molecules that induce cell death after antibody binding and patients. Number of prior lines and previous refractoriness to internalization. Such effector molecules include cytotoxic chemotherapy should be carefully evaluated before choosing the agents (antibody-drug conjugate, ADC), bacterial or plant salvage therapy, and allogeneic hematopoietic transplantation protein toxins (immunotoxins), and radiopharmaceutical should be considered if a response has been achieved. agents (radiolabeled mAb) (123). New treatment approaches include monoclonal antibodies Polatuzumab-vedotin (Pola) is an ADC that consists of (mAbs), antibody-drug conjugates, bispecific antibodies (bsAbs), CD79b-binding mAb conjugated to an antimitotic agent: immunomodulatory drugs, checkpoint inhibitors, molecular monomethyl auristatin E (MMAE) (124). Polatuzumab-vedotin pathway inhibitors, and epigenetic-modifying molecules. selectively targets B cells into which MMAE is internalized and Current therapeutic options that should be considered for the cleaved from its linker by lysosomal proteases before binding to treatment of patients who have failed to CART19 are reviewed microtubules to inhibit cell division and induce apoptosis (125). below (Figure 3), and main toxicities are listed in Table 2. Polatuzumab vedotin plus bendamustine and rituximab (BR) received regulatory approvals for transplantation-ineligible R/R Monoclonal Antibodies DLBCL based on primary results from a phase 1b/2 study mAbs exert their antitumor capacity through several comparing Pola-BR versus BR alone. In this scenario, Pola-BR mechanisms, including complement-dependent cytotoxicity, has shown to improve CR rate (40% vs. 17.5%) and PFS (median antibody-dependent cellular cytotoxicity, and antibody- 9.5 vs. 3.7 months) (126). Results from an extension cohort dependent cell-mediated phagocytosis commonly regulated via confirmed significant survival benefit with Pola-BR, but a lower interaction between the Fc antibody chain and Fcg receptors on ORR 41.5% and similar CR rate 38.7%. This trial excluded immune effector cells: natural killer cells, macrophages, and gd T patients treated with CART19 therapy (127). German cells (118). experience described Pola-BR and other combinations (Pola-B, Tafasitamab is an Fc-engineered, humanized, CD19 mAb Pola-R-CHP, Pola-R-Gemcitabine, Pola-R), showing ORR 48% with the introduction of S239D and I332E amino acid and 14.8% of CRs in patients with R/R DLBCL (124). On another substitutions that leads to an enhancement of antigen- hand, Greek experienced reported ORR of 43% and 25% of CRs Frontiers in Immunology | www.frontiersin.org 10 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure TABLE 2 | Therapeutic Options After CART Failure: Safety Profile. AGENT DESIGN SCHEME SIDE EFFECTS Tafasitamab mAb Tafasitamab- Any grade: Rash (27%), diarrhea (32%). Grade ≥3: Neutropenia (48%), thrombocytopenia (17%), and febrile Lenalidomide neutropenia (12%). SAEs: pneumonia (6%), febrile neutropenia (6%), pulmonary embolism (4%), bronchitis (2%), atrial fibrillation (2%), and congestive cardiac failure (2%). CD19 Polatuzumab- ACD Pola-BR Any grade: Peripheral neuropathy grade 1–2 (43-6%), infections (23%). Grade ≥3: Neutropenia (46.2%), vedotin thrombocytopenia (41%), increased GGT (17%), and febrile neutropenia (10.3%). Three fatal AEs (7.6%): pneumonia, hemoptysis, and pulmonary edema. CD79b Loncastuximab ACD Single agent Any grade: nausea (23%), Peripheral edema (19%) Grade ≥3: Neutropenia (26%), thrombocytopenia (18%), and tesirine febrile neutropenia (3%). Fatal AEs (6%): sepsis, small intestinal perforation, pneumonia, and acute kidney injury. CD19 Glofitamab bsAb Single agent Grade ≥3: Neutropenia (25.1%), thrombocytopenia (8.2%), and febrile neutropenia (2.9%). CRS* (50.3%): 46.7% grades 1–2 and 3.5% grade 3 or 4. Neurologic AEs (43.3%), ICANS**-like (5.3%). Fatal AEs (1.2%): GI hemorrhage and septic shock. CD20 – CD3 Mosunetuzumab bsAb Single agent Grade ≥3: Neutropenia (25.4%), hypophosphatemia (15.2%), anemia (9.1%), and febrile neutropenia (3.6%). CRS* (27.4%): 26.4% grades 1–2 and 1% grade 3. Grade 3 neurologic AEs (4.1%). Fatal AEs (1.5%): hemophagocytic lymphohistiocytosis, sepsis, candida sepsis, and pneumonia. CD20 – CD3 Epcoritamab bsAb Single agent Injection site reaction (47%): grades 1–2. Grade ≥3: pneumonia (12%), dyspnea (6%). CRS* (59%) only grades 1– 2. No discontinuations occurred due to treatment-related AEs or treatment-related deaths. CD20-CD3 *Cytokine release syndrome **Immune effector cells-associated neurotoxicity syndrome. in patients with B-NHL, including mainly R/R DLBCL but also sequence-selective DNA cross-linking agents that do not cause MCL, PMBCL, and transformed FL (128). Unfortunately, distortion of the DNA structure. Less DNA distortion may hide CART19 treated patients was barely represented in those PBD dimers from DNA repair mechanisms and appears to help studies (124, 128). in maintaining their biological activity and persistence in cells Coltuximab ravtansine is an ADC consisting of a humanized (131, 132). A multicenter, single-arm phase 2 trial in patients IgG1 anti-CD19 mAb (SAR3419) conjugated to DM4, a potent with R/R DLBCL (median previous lines of treatment: 3; range: antimitotic agent that inhibits tubulin polymerization and 2–4) was designed to determine Loncastuximab tesirine efficacy. microtubule assembly. After binding to the cell-surface Reported ORR was 48.3% with 24.1% of CRs and a median PFS antigen, the complex immunoconjugate antigen is internalized of 4.9 months. Nine percent of patients received CART19 and undergoes lysosomal degradation, generating an therapy prior to Loncastuximab tesirine, all of them with a intermediate unstable metabolite (Lysine-SPDB-DM4) that biopsy-proven CD19-tumor expression; ORR was similar to undergoes additional intracellular processing to produce DM4 that of the overall study population (132, 133). The median (129). Modest efficacy was displayed by Coltuximab-ravtansine time between CART19 failure and ADC treatment was 7 months in a Phase 2 clinical trial for the treatment of R/R DLBCL, with (range: 45–400 days), and in 77% of cases was administered as ORR 43% and CR rate 14.6%. The study population has first therapy post-CART19. ORR was 46.2% and 15.4% achieved previously received a median of two treatments excluding CR (134). CART19 (130). Brentuximab vedotin (BV) is an ADC constituted by an anti- Loncastuximab tesirine is an ADC comprising a humanized CD30 mAb (SGN-30) conjugates to MMAE (135). BV has been IgG1 anti- CD19 antibody (RB4v1.2) conjugated to SG3199, a approved for classical Hodgkin lymphoma, primary cutaneous pyrrolobenzodiazepine (PDB) dimer toxin. PDB dimers are anaplastic large cell lymphoma, and systemic anaplastic large-cell Frontiers in Immunology | www.frontiersin.org 11 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure FIGURE 3 | Management proposal for patients with R/R DLBCL who fail CART19 treatment. Novel clinically relevant therapies based on CD19 tumor expression are shown. CR, complete response; PR, partial response; SD, stable disease; PD, progressive disease; BR, bendamustine-rituximab. lymphoma (136). CD30 protein is expressed in 14% to 25% of absence of an Fc region. bsAbs that include an Fc region can DLBCL patients depending on the cutoff to assign positivity be further divided into those that exhibit a structure resembling (136–138). BV has shown antitumor activity in patients with R/R that of an IgG molecule and those that contain additional DLBCL [median previous lines of treatment: 3 (range: 1–6)] in a binding sites. Different configurations of bsAbs allow phase 2 study with ORR of 44% and 17% CR rate. Interestingly, modulation of valency, size, flexibility, pharmacokinetic, and no statistical correlation between response and level of CD30 pharmacodynamic properties (145). expression was found, since 12% of patients with little to no Typically, bsAbs consist of a T‐cell receptor‐specific mAb or CD30, determined by visual immunohistochemistry, achieved a mAb‐derived fragment that is able to activate and expand resting CR (136, 139). Patients treated with CART19 were not included T cells fused to a second mAb or mAb fragment directed against in the study, as it was not yet available as a SOC (136). a tumor target antigen. Thus, bsAbs induce attached T cells Pinatuzumab vedotin (Pina) is an ADC composed by a specific cytotoxicity effect against tumor target cells without the humanized anti-CD22 monoclonal IgG1 antibody requirement of MHC‐mediated antigen presentation (144). (MCDT2219A) with MMAE, linked to the reduced cysteines of Blinatumomab (Blina) comprises an anti-CD19 scFv linked the antibody via a protease cleavable linker, maleimidocaproyl- through a linker to an anti-CD3 scFv. Blina is a bispecific T-cell valine-citrulline-p-aminobenzoyloxycarbonyl (MC-vc-PAB) engaging (BiTE) antibody construct. Blina molecules are small (140, 141). The efficacy of Pinatuzumab vedotin was evaluated and rapidly cleared from circulation with a terminal half-life of in combination with Rituximab for the treatment of R/R DLBCL 1.25 h requiring continuous intravenous infusion (IV) (146, [median previous lines of treatment: 3 (range: 1–3)] in a Phase 2 147). A phase 2, single agent clinical trial evaluated the use of open-label, randomized clinical trial comparing Pola-R versus Blina against R/R DLBCL [median previous lines of treatment: 3 Pina-R. Pina-R achieved 60% of ORR and 26% of CRs. (range: 1–7)] showing modest efficacy (ORR 43% and CR rate Meanwhile, Pola-R reached a 54% ORR and 21%. CR rate. 19%) (146). Another phase 2 study evaluated the efficacy of Blina Median DOR was shown to be longer for R-Pola than R-Pina as second salvage for R/R DLBCL and found a 37% ORR with (13.4 versus 6.2 months, respectively). No correlation between 22% CRs and a median PFS of 2.5 months (148). These studies CD22 expression and tumor shrinkage for Pina was observed. did not include patients treated with CART19. The inclusion of patients previously treated with CART therapy Glofitamab is a full-length bsAb possessing a 2:1 structure was not reported. Data derived from this study suggest that R- with bivalency for CD20 on B cells and monovalency for CD3 on Pina and R-Pola may have antitumor effect against R/R DLBCL T cells. CD20 bivalency preserves this potency in the presence of but short-term disease control (142, 143). competing anti-CD20 antibodies, providing the opportunity for pre or cotreatment with these agents. Patients with R/R B-NHL, Bispecific Antibodies including DLBCL, tFL, or other aggressive histology, were treated The term “bispecific antibody” refers to an antibody or an with Glofitamab alone as part of a phase 1 dose-escalation study. antibody‐derived protein construct that has binding Patients had a median of 3 (range: 1–13) prior lines of therapy. A specificities for two different antigens. bsAbs combine two single dose of Obinutuzumab was administered 7 days before different monospecific antigen‐binding regions, or variable treatment with Glofitamab to reduce TB and expected toxicity. regions, from different antibodies to achieve a single antibody Glofitamab has longer half-life compared with BiTES (non-Fc), or antibody‐derived molecule with bispecific antigen binding allowing it to be administered every 14 or 21 days. Patients (144). bsAbs can be classified according to the presence or previously treated with CART19 were poorly represented in this Frontiers in Immunology | www.frontiersin.org 12 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure study. Across all doses, ORR was 53.8% and CR rate was 36.8%. treated (n = 12) with an ORR of 25% and 8% CR (n = 1). At the recommended dose, ORR and CR were 71.4% and 64.3%, Immune profiling revealed increased CAR T-cell activation and respectively (149). Furthermore, preliminary data from the use of proliferation and less T-cell exhaustion in clinical responders Glofitamab in combination with Polatuzumab vedotin for the (104). Furthermore, results of another small study revealed a treatment of R/R B-NHL reported ORR of 73% and 51.5% of higher PD-1/PD-L1 expression in responsive patients with anti– CRs. With a short follow-up and small number of treated PD-1 therapy as compared to that in non-responders (156). patients, these encouraging data need to be confirmed in larger Safety and efficacy of anti–PD-1 administration early after trials (150). CAR19 T-cell infusion are being evaluated in clinical trials, Mosunetuzumab is a full-length, humanized, IgG1–based with initial data showing 91% ORR and 64% CR after Liso-cel bsAb targeting CD20 and CD3 (151). A phase 1/1b dose- and Durvalumab combination (157). escalation and expansion study evaluated Mosunetuzumab for Moreover, efficacy of the combination of an anti-CD20 mAb, the treatment of patients with R/R DLBCL. The study population atezolizumab (anti-PDL1) and Polatuzumab vedotin for the included 9.6% of patients who had received prior CART19 treatment of R/R DLBCL was evaluated in a phase 1b study. treatment. Mosunetuzumab was administered intravenously as This clinical trial revealed a 13% CR rate, but significant low and intermediate step-up doses on days 1 and 8 of cycle 1, toxicities, with 24% of grade 3–5 adverse events and 10% of with the target dose on day 15 and on day 1 of subsequent 21-day serious adverse events. Based on safety issues and the limited cycles. ORR was 34.9% and CR rate was 19.4%. In the post- efficacy, no further development of that triplet combination was CART19 therapy group (n = 15), ORR was 36.8% and CR was pursued (158). 26.3%, but DOR was not shown in this particular subgroup of patients (152). Molecular Pathway Inhibitors Odronextamab (REGN1979) is a first-in-class, hinge- Exportin 1 (XPO1), one of eight nucleo-cytoplasmic shuttling stabilized, fully human IgG4 bsAb directed against CD20 and proteins involved in the export of proteins from the nucleus to CD3. A phase 1 clinical trial was developed to evaluate efficacy of the cytoplasm, is overexpressed in DLBCL. XPO1 blockade in Odronextamab for the treatment of R/R B-NHL including R/R DLBCL re-establishes the growth regulating effects of multiple DLBCL. Odronextamab is administered in a step-up dosing tumor suppressor proteins by forcing their nuclear retention and regimen and dexamethasone was administered as potentially reverses chemotherapy resistance. Selinexor, an oral premedication to reduce expected toxicities. Preliminary results selective inhibitor of XPO1, was studied in transplant-ineligible reported that, among R/R DLBCL patients, 37% achieved some R/R DLBCL (2–5 previous lines of treatment) in the open-label, response and 26% had CR. In those DLBCL patients who single-arm SADAL phase 2b trial. ORR was found to be 28% relapsed after CART therapy, 31% responded, with 22% with 12% CR rate and a median PFS of 2.6 months only (159). CRs (153). Epcoritamab is a full-length human IgG1 bsAb recognizing Allogeneic Hematopoietic Cell CD3 and CD20, generated by a new method, using controlled Transplantation Fab-arm exchange of mAb half-molecules. It was designed to Allo-HSCT remains an SOC for DLBCL patients with offer a longer plasma half-life compared to others bsAbs. Fc- chemosensitive relapse after prior ASCT (160). Allo-HSCT mediated effector functions were silenced by the introduction of registry studies on DLBCL patients relapsing after ASCT three amino acid mutations in the Fc region (154). Safety and consistently showed 3-year PFS rates of 30% to 40%. Allo- efficacy of Epcoritamab were assessed in a phase 1/2 clinical trial HSCT is a potentially curative cellular immunotherapy for R/R to treat R/R B-NHL patients, including R/R DLBCL. In contrast DLBCL and should be considered as a therapeutic option in this to previous bsAbs, Epcoritamab administration is subcutaneous setting for eligible patients. Another potential field of research for (SC). A priming SC dose was given on day 1 of cycle 1 and an allo-HSCT might be pre-emptive treatment of incomplete intermediate dose on day 8 of cycle 1, followed by full doses responses to CAR19 T cells (161). Recently, a series of patients administered in 28-day cycles until disease progression or receiving allo-HSCT after CART19 have reported a 2-year PFS of unacceptable toxicity. Eleven percent of patients included in 30% and OS of 40%, although non-relapse mortality was as high the study had failed CART19 therapy. ORR was 68%, with 38% as 25% (162). of them achieving CR. Among four patients with R/R DLBCL who had received CART19 before epcoritamab, all of them responded with two of them achieving a CR (155). CONCLUSIONS Immune Checkpoint Inhibitors High baseline levels of inhibitory checkpoint protein expression Following the designation as a breakthrough treatment, CART (PD-L1, LAG3, and TIM3) by tumor and tumor therapy had an exponential growth in basic and clinical microenvironment cells have been reported in patients who do research in the field. Hematological malignancies and patients not respond to CAR T cells (19, 24). A phase 1/2a study with B-cell tumors in particular have significant clinical benefit evaluated the efficacy of Pembrolizumab (an anti–PD-1 from this treatment. However, 5 years from the first FDA- immune checkpoint inhibitor) in patients with B-NHL after approval CART therapy, it is becoming evident the limitations failure to CART19 therapy. A small number of patients were of this therapy, and further improvements are needed to allow Frontiers in Immunology | www.frontiersin.org 13 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure translation of a clinical benefit to a significant proportion of AUTHOR CONTRIBUTIONS patients that are actually unresponsive. Preclinical and clinical CART research has advanced rapidly to identify biological and AC and JB performed the literature search and conducted clinical factors associated with response. In contrast to other extraction of data from relevant studies. AC, JB, CA-F, and therapies, tumor biological features are not the most critically LE-G critically reviewed the literature search. AC, JB, CA-F, involved determining a response to CART therapy. Other non- and LE-G wrote and revised the manuscript, figures, references, tumor specific factors such as CART production technologies, and tables. All authors contributed to the article and approved T-cell subsets composition, T-cell features within the “starting the submitted version. material”, functional state of pre-infusion CAR T cells (i.e., activation patterns and expression of inhibitory receptors), in addition to in vivo expansion and persistence of CAR T cells, FUNDING have been associated in different clinical trials as critical This work was supported in part by grants from La Marató TV3 determinants of response. Further validation and applicability (Exp. 20130710), Deutsche José Carreras Leukämie Stiftung of some of these studies will potentially allow to identifying (DJCSL 10R/2016), Beca Carlos Antonio Ló pez (Gobierno patients with higher chances of benefit from CART therapy. paraguayo), Instituto de Salud Carlos III (PI15/1383 and PI18/ The prognosis of relapse/refractory patients not responding to 01023), Fondos FEDER Fundació n Bancaria ‘La Caixa’, CART therapy is extremely poor, and this situation represents Ministerio de Economı́a y Competitividad (RETOS; RTC 2015- an unmet medical need. Significant efforts are being made to 3393-1) and AGAUR (2017SGR1395). identify new therapies that may rescue patients in that situation. Recent clinical trials with new drugs, including bispecific antibodies, drug-conjugated antibodies, CART ACKNOWLEDGMENTS targeting antigens other tan CD19, and allogeneic hematopoietic transplantation, would open a new future for Figures 1 and Figure 2 were created with BioRender.com patients in the post-CART19 era. support. and T-Cell Receptors. Proc Natl Acad Sci U.S.A. (1993) 90:720–4. REFERENCES doi: 10.1073/pnas.90.2.720 1. World Health Organization. Global cancer statistics 2020: GLOBOCAN 10. Brocker T, Karjalainen K. Signals Through T Cell Receptor-z Chain Alone Estimates of Incidence and Mortality. Int Agency Res Cancer (2020) 68:1. are Insufficient to Prime Resting T Lymphocytes. J Exp Med (1995) 2. Sehn LH, Gascoyne RD. Diffuse Large B-Cell Lymphoma: Optimizing 181:1653–9. doi: 10.1084/jem.181.5.1653 Outcome in the Context of Clinical and Biologic Heterogeneity. Blood 11. Maher J, Brentjens RJ, Gunset G, Rivière I, Sadelain M. Human T- (2015) 125:22–32. doi: 10.1182/blood-2014-05-577189 Lymphocyte Cytotoxicity and Proliferation Directed by a Single Chimeric 3. Coiffier B, Thieblemont C, van den Neste E, Lepeu G, Plantier I, Castaigne S, Tcrz/CD28 Receptor. Nat Biotechnol (2002) 20:70–5. doi: 10.1038/nbt0102- et al. Long-Term Outcome of Patients in the LNH-98.5 Trial, the First 70 Randomized Study Comparing Rituximab-CHOP to Standard CHOP 12. Brentjens RJ, Santos E, Nikhamin Y, Yeh R, Matsushita M, la Perle K, et al. Chemotherapy in DLBCL Patients: A Study by the Groupe D’Etudes Des Genetically Targeted T Cells Eradicate Systemic Acute Lymphoblastic Lymphomes De L’adulte. Blood (2010) 116:2040–5. doi: 10.1182/blood- Leukemia Xenografts. Clin Cancer Res (2007) 13:5426–35. doi: 10.1158/ 2010-03-276246 1078-0432.CCR-07-0674 4. Crump M, Neelapu SS, Farooq U, van den Neste E, Kuruvilla J, Westin J, 13. Wang J, Press OW, Lindgren CG, Greenberg P, Riddell S, Qian X, et al. et al. Outcomes in Refractory Diffuse Large B-Cell Lymphoma: Results From Cellular Immunotherapy for Follicular Lymphoma Using Genetically the International SCHOLAR-1 Study. Blood (2017) 130:1800–8. Modified CD20-Specific CD8+ Cytotoxic T Lymphocytes. Mol Ther doi: 10.1182/blood-2017-03-769620 (2004) 9:577–86. doi: 10.1016/j.ymthe.2003.12.011 5. Gisselbrecht C, Glass B, Mounier N, Gill DS, Linch DC, Trneny M, et al. 14. Kochenderfer JN, Wilson WH, Janik JE, Dudley ME, Stetler-Stevenson M, Salvage Regimens With Autologous Transplantation for Relapsed Large B- Feldman SA, et al. Eradication of B-Lineage Cells and Regression of Cell Lymphoma in the Rituximab Era. J Clin Oncol (2010) 28:4184–90. Lymphoma in a Patient Treated With Autologous T Cells Genetically doi: 10.1200/JCO.2010.28.1618 Engineered to Recognize CD19. Blood (2010) 116:4099–102. doi: 10.1182/ 6. van den Neste E, Schmitz N, Mounier N, Gill D, Linch D, Trneny M, et al. blood-2010-04-281931 Outcomes of Diffuse Large B-Cell Lymphoma Patients Relapsing After 15. Kochenderfer JN, Dudley ME, Feldman SA, Wilson WH, Spaner DE, Maric Autologous Stem Cell Transplantation: An Analysis of Patients Included in I, et al. B-Cell Depletion and Remissions of Malignancy Along With the CORAL Study. Bone Marrow Transplant (2017) 52:216–21. Cytokine-Associated Toxicity in a Clinical Trial of Anti-CD19 Chimeric- doi: 10.1038/bmt.2016.213 Antigen-Receptor-Transduced T Cells. Blood (2012) 119:2709–20. 7. Rosenberg SA, Yang JC, Sherry RM, Kammula US, Hughes MS, Phan GQ, doi: 10.1182/blood-2011-10-384388 et al. Durable Complete Responses in Heavily Pretreated Patients With 16. Kochenderfer JN, Dudley ME, Kassim SH, Somerville RPT, Carpenter RO, Metastatic Melanoma Using T-Cell Transfer Immunotherapy. Clin Cancer Maryalice SS, et al. Chemotherapy-Refractory Diffuse Large B-Cell Res (2011) 17:4550–7. doi: 10.1158/1078-0432.CCR-11-0116 Lymphoma and Indolent B-Cell Malignancies can be Effectively Treated 8. Gross G, Waks T, Eshhar Z. Expression of Immunoglobulin-T-Cell With Autologous T Cells Expressing an Anti-CD19 Chimeric Antigen Receptor Chimeric Molecules as Functional Receptors With Antibody- Receptor. J Clin Oncol (2015) 33:540–9. doi: 10.1200/JCO.2014.56.2025 Type Specificity. Proc Natl Acad Sci U.S.A. (1989) 86:10024–8. 17. Porter DL, Levine BL, Kalos M, Bagg A, June CH. Chimeric Antigen doi: 10.1073/pnas.86.24.10024 Receptor–Modified T Cells in Chronic Lymphoid Leukemia. New Engl J 9. Eshhar Z, Waks T, Gross G, Schindler DG. Specific Activation and Targeting Med (2011) 365:725–33. doi: 10.1056/nejmoa1103849 of Cytotoxic Lymphocytes Through Chimeric Single Chains Consisting of 18. Grupp SA, Kalos M, Barrett D, Aplenc R, Porter DL, Rheingold SR, et al. Antibody-Binding Domains and the g or z Subunits of the Immunoglobulin Chimeric Antigen Receptor–Modified T Cells for Acute Lymphoid Frontiers in Immunology | www.frontiersin.org 14 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure Leukemia. New Engl J Med (2013) 368:1509–18. doi: 10.1056/ Lymphodepletion Enhances the Efficacy of Adoptively Transferred nejmoa1215134 Tumor-Specific CD8+ T Cells. J Exp Med (2005) 202:907–12. 19. Schuster SJ, Svoboda J, Chong EA, Nasta SD, Mato AR, Anak Ö, et al. doi: 10.1084/jem.20050732 Chimeric Antigen Receptor T Cells in Refractory B-Cell Lymphomas. New 36. Turtle CJ, Hanafi LA, Berger C, Gooley TA, Cherian S, Hudecek M, et al. Engl J Med (2017) 377:2545–54. doi: 10.1056/nejmoa1708566 CD19 CAR-T Cells of Defined CD4+:CD8+ Composition in Adult B Cell 20. Sommermeyer D, Hudecek M, Kosasih PL, Gogishvili T, Maloney DG, ALL Patients. J Clin Invest (2016) 126:2123–38. doi: 10.1172/JCI85309 Turtle CJ, et al. Chimeric Antigen Receptor-Modified T Cells Derived From 37. Dudley ME, Yang JC, Sherry R, Hughes MS, Royal R, Kammula U, et al. Defined CD8+ and CD4+ Subsets Confer Superior Antitumor Reactivity In Adoptive Cell Therapy for Patients With Metastatic Melanoma: Evaluation Vivo. . Leukemia (2016) 30:492–500. doi: 10.1038/leu.2015.247 of Intensive Myeloablative Chemoradiation Preparative Regimens. J Clin 21. Turtle CJ, Hanafi L-A, Berger C, Hudecek M, Pender B, Robinson E, et al. Oncol (2008) 26:5233–9. doi: 10.1200/JCO.2008.16.5449 Immunotherapy of non-Hodgkin’s Lymphoma With a Defined Ratio of CD8 38. Kochenderfer JN, Somerville RPT, Lu T, Shi V, Bot A, Rossi J, et al. + and CD4+ CD19-Specific Chimeric Antigen Receptor-Modified T Cells. Lymphoma Remissions Caused by Anti-CD19 Chimeric Antigen Receptor Sci Transl Med (2016) 8:355ra116. doi: 10.1126/scitranslmed.aaf8621 T Cells are Associated With High Serum Interleukin-15 Levels. J Clin Oncol 22. Kochenderfer JN, Somerville RPT, Lu T, Yang JC, Sherry RM, Feldman SA, (2017) 35:1803–13. doi: 10.1200/JCO.2016.71.3024 et al. Long-Duration Complete Remissions of Diffuse Large B Cell 39. Dekker L, Calkoen FG, Jiang Y, Blok H, Veldkamp SR, de Koning C, et al. Lymphoma After Anti-CD19 Chimeric Antigen Receptor T Cell Therapy. Fludarabine Exposure Predicts Outcome After CD19 CAR T-Cell Therapy Mol Ther (2017) 25:2245–53. doi: 10.1016/j.ymthe.2017.07.004 in Children and Young Adults With Acute Leukemia. Blood Adv (2022) 23. Locke FL, Neelapu SS, Bartlett NL, Siddiqi T, Chavez JC, Hosing CM, et al. 6:1969–76. doi: 10.1182/bloodadvances.2021006700 Phase 1 Results of ZUMA-1: A Multicenter Study of KTE-C19 Anti-CD19 40. Fabrizio VA, Boelens JJ, Mauguen A, Baggott C, Prabhu S, Egeler E, et al. CAR T Cell Therapy in Refractory Aggressive Lymphoma. Mol Ther (2017) Optimal Fludarabine Lymphodepletion is Associated With Improved 25:285–95. doi: 10.1016/j.ymthe.2016.10.020 Outcomes After CAR T-Cell Therapy. Blood Adv (2022) 6:1961–8. 24. Schuster SJ, Bishop MR, Tam CS, Waller EK, Borchmann P, McGuirk JP, doi: 10.1182/bloodadvances.2021006418 et al. Tisagenlecleucel in Adult Relapsed or Refractory Diffuse Large B-Cell 41. Locke FL, Rossi JM, Neelapu SS, Jacobson CA, Miklos DB, Ghobadi A, et al. Lymphoma. New Engl J Med (2019) 380:45–56. doi: 10.1056/nejmoa1804980 Tumor Burden, Inflammation, and Product Attributes Determine Outcomes 25. Abramson JS, Palomba ML, Gordon LI, Lunning MA, Wang M, Arnason J, of Axicabtagene Ciloleucel in Large B-Cell Lymphoma. Blood Adv (2020) et al. Lisocabtagene Maraleucel for Patients With Relapsed or Refractory 4:4898–911. doi: 10.1182/BLOODADVANCES.2020002394 Large B-Cell Lymphomas (TRANSCEND NHL 001): A Multicentre 42. Vercellino L, di Blasi R, Kanoun S, Tessoulin B, Rossi C, D’Aveni-Piney M, Seamless Design Study. Lancet (2020) 396:839–52. doi: 10.1016/S0140- et al. Predictive Factors of Early Progression After CAR T-Cell Therapy in 6736(20)31366-0 Relapsed/Refractory Diffuse Large B-Cell Lymphoma. Blood Adv (2020) 26. Nastoupil LJ, Jain MD, Feng L, Spiegel JY, Ghobadi A, Lin Y, et al. Standard- 4:5607–15. doi: 10.1182/bloodadvances.2020003001 Of-Care Axicabtagene Ciloleucel for Relapsed or Refractory Large B-Cell 43. Awasthi R, Pacaud L, Waldron E, Tam CS, Jäger U, Borchmann P, et al. Lymphoma: Results From the US Lymphoma CAR T Consortium. J Clin Tisagenlecleucel Cellular Kinetics, Dose, and Immunogenicity in Relation to Oncol (2020) 38:3119–28. doi: 10.1200/JCO.19.02104 Clinical Factors in Relapsed/Refractory DLBCL. Blood Adv (2020) 4:560–72. 27. Jain MD, Bachmeier CA, Phuoc VH, Chavez JC. Axicabtagene Ciloleucel doi: 10.1182/bloodadvances.2019000525 (KTE-C19), an Anti-CD19 CAR T Therapy for the Treatment of Relapsed/ 44. Locke FL, Ghobadi A, Jacobson CA, Miklos DB, Lekakis LJ, Oluwole OO, Refractory Aggressive B-Cell non-Hodgkin’s Lymphoma. Ther Clin Risk et al. Long-Term Safety and Activity of Axicabtagene Ciloleucel in Manage (2018) 14:1007–17. doi: 10.2147/TCRM.S145039 Refractory Large B-Cell Lymphoma (ZUMA-1): A Single-Arm, 28. Hirayama A v., Gauthier J, Hay KA, Voutsinas JM, Wu Q, Gooley T, et al. Multicentre, Phase 1–2 Trial. Lancet Oncol (2019) 20:31–42. doi: 10.1016/ The Response to Lymphodepletion Impacts PFS in Patients With Aggressive S1470-2045(18)30864-7 non-Hodgkin Lymphoma Treated With CD19 CAR T Cells. Blood (2019) 45. Yan ZX, Li L, Wang W, OuYang BS, Cheng S, Wang L, et al. Clinical Efficacy 133:1876–87. doi: 10.1182/blood-2018-11-887067 and Tumor Microenvironment Influence in a Dose-Escalation Study of 29. Garcia-Recio M, Wudhikarn K, Pennisi M, Alonso-Trillo R, Flynn J, Shouval Anti-CD19 Chimeric Antigen Receptor T Cells in Refractory B-Cell non- R, et al. The International Prognostic Index Is Associated With Outcomes in Hodgkin’s Lymphoma. Clin Cancer Res (2019) 25:6995–7003. doi: 10.1158/ Diffuse Large B Cell Lymphoma After Chimeric Antigen Receptor T Cell 1078-0432.CCR-19-0101 Therapy. Transplant Cell Ther (2021) 27:233–40. doi: 10.1016/ 46. Gardner RA, Finney O, Annesley C, Brakke H, Summers C, Leger K, et al. j.jtct.2020.10.022 Intent-To-Treat Leukemia Remission by CD19 CAR T Cells of De Fi Ned 30. Neelapu SS, Locke FL, Bartlett NL, Lekakis LJ, Miklos DB, Jacobson CA, Formulation and Dose in Children and Young Adults. Blood (2017) et al. Axicabtagene Ciloleucel CAR T-Cell Therapy in Refractory Large B- 129:3322–31. doi: 10.1182/blood-2017-02-769208 Cell Lymphoma. New Engl J Med (2017) 377:2531–44. doi: 10.1056/ 47. Finney OC, Brakke H, Rawlings-Rhea S, Hicks R, Doolittle D, Lopez M, et al. nejmoa1707447 CD19 CAR T Cell Product and Disease Attributes Predict Leukemia 31. Xu-Monette ZY, Wu L, Visco C, Tai YC, Tzankov A, Liu WM, et al. Remission Durability. J Clin Invest (2019) 129:2123–32. doi: 10.1172/ Mutational Profile and Prognostic Significance of TP53 in Diffuse Large B- JCI125423 Cell Lymphoma Patients Treated With R-CHOP: Report From an 48. Park JH, Rivière I, Gonen M, Wang X, Sé né chal B, Curran KJ, et al. Long- International DLBCL Rituximab-CHOP Consortium Program Study. Term Follow-Up of CD19 CAR Therapy in Acute Lymphoblastic Leukemia. Blood (2012) 120:3986–96. doi: 10.1182/blood-2012-05-433334 New Engl J Med (2018) 378:449–59. doi: 10.1056/nejmoa1709919 32. Shouval R, Alarcon Tomas A, Fein JA, Flynn JR, Markovits E, Mayer S, et al. 49. Mueller KT, Waldron E, Grupp SA, Levine JE, Laetsch TW, Pulsipher MA, Impact of TP53 Genomic Alterations in Large B-Cell Lymphoma Treated et al. Clinical Pharmacology of Tisagenlecleucel in B-Cell Acute With CD19-Chimeric Antigen Receptor T-Cell Therapy. J Clin Oncol (2022) Lymphoblastic Leukemia. Clin Cancer Res (2018) 24:6175–84. 40:369–81. doi: 10.1200/JCO.21.02143 doi: 10.1158/1078-0432.CCR-18-0758 33. Jain MD, Zhao H, Wang X, Atkins R, Menges M, Reid K, et al. Tumor 50. Bishop MR, Maziarz RT, Waller EK, Jäger U, Westin JR, McGuirk JP, et al. Interferon Signaling and Suppressive Myeloid Cells are Associated With Tisagenlecleucel in Relapsed/Refractory Diffuse Large B-Cell Lymphoma CAR T-Cell Failure in Large B-Cell Lymphoma. Blood (2021) 137:2621–33. Patients Without Measurable Disease at Infusion. Blood Adv (2019) 3:2230– doi: 10.1182/blood.2020007445 6. doi: 10.1182/bloodadvances.2019000151 34. Chong EA, Ruella M, Schuster SJ. Five-Year Outcomes for Refractory B-Cell 51. Sasanelli M, Meignan M, Haioun C, Berriolo-Riedinger A, Casasnovas R, Lymphomas With CAR T-Cell Therapy. New Engl J Med (2021) 384:673–4. Biggi A, et al. Pretherapy Metabolic Tumour Volume Is an Independent doi: 10.1056/nejmc2030164 Predictor of Outcome in Patients With Diffuse Large B-Cell Lymphoma. Eur 35. Gattinoni L, Finkelstein SE, Klebanoff CA, Antony PA, Palmer DC, J Nucl Med Mol Imaging (2022) 41(11):2017–22. doi: 10.1007/s00259-014- Spiess PJ, et al. Removal of Homeostatic Cytokine Sinks by 2822-7 Frontiers in Immunology | www.frontiersin.org 15 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure 52. Song MK, Chung JS, Shin HJ, Lee SM, Lee SE, Lee HS, et al. Clinical Confer Superior Antitumor Immunity Compared With Effector Memory T Significance of Metabolic Tumor Volume by PET / CT in Stages II and III of Cells. Proc Natl Acad Sci U S A (2005) 102:9571–6. doi: 10.1073/ Diffuse Large B Cell Lymphoma Without Extranodal Site Involvement. Ann pnas.0503726102 Hematol (2012) 91(5) 697–703. doi: 10.1007/s00277-011-1357-2 70. Gattinoni L, Zhong X-S, Palmer DC, Ji1 Y, Hinrichs CS, Yu Z, et al. 53. Feugier P, Chartier L, Fruchart C, Vercellino L, Cottereau A, Casasnovas O, Wnt Signaling Arrests Effector T Cell Differentiation and Generates et al. High Total Metabolic Tumor Volume at Baseline Predicts Survival CD8+ Memory Stem Cells. Nat Med (2009) 15:808–13. doi: 10.1038/ Independent of Response to Therapy. Blood (2020) 135:1396–1405. nm.1982 doi: 10.1182/blood.2019003526 71. Mackall CL, Fleisher TA, Brown MR, Andrich MP, Chen CC, Feuerstein IM, 54. Dean EA, Mhaskar RS, Lu H, Mousa MS, Krivenko GS, Lazaryan A, et al. et al. Distinctions Between CD8+ and CD4+ T-Cell Regenerative Pathways High Metabolic Tumor Volume Is Associated With Decreased E Ffi Cacy of Result in Prolonged T-Cell Subset Imbalance After Intensive Chemotherapy. Axicabtagene Ciloleucel in Large B-Cell Lymphoma. Blood Adv (2020) 4 Blood (1997) 89:3700–7. doi: 10.1182/blood.V89.10.3700 (14):3268–76. doi: 10.1182/bloodadvances.2020001900 72. Berger C, Jensen MC, Lansdorp PM, Gough M, Elliott C, Riddell SR. 55. Hong R, Tan Su Yin E, Wang L, Zhao X, Zhou L, Wang G, et al. Tumor Adoptive Transfer of Effector CD8+ T Cells Derived From Central Burden Measured by 18F-FDG PET/CT in Predicting Efficacy and Adverse Memory Cells Establishes Persistent T Cell Memory in Primates. J Clin Effects of Chimeric Antigen Receptor T-Cell Therapy in Non-Hodgkin Invest (2008) 118:294–305. doi: 10.1172/JCI32103 Lymphoma. Front Oncol (2021) 11:713577. doi: 10.3389/fonc.2021.713577 73. Alvarez-Ferná ndez C, Escribà-Garcia L, Caballero AC, Escudero-Ló pez E, 56. Wang J, Hu Y, Yang S, Wei G, Zhao X, Wu W, et al. Biology of Blood and Ujaldó n-Miró C, Montserrat-Torres R, et al. Memory Stem T Cells Modified Marrow Transplantation Role of Fluorodeoxyglucose Positron Emission With a Redesigned CD30-Chimeric Antigen Receptor Show An Enhanced Tomography / Computed Tomography in Predicting the Adverse Effects of Antitumor Effect in Hodgkin Lymphoma. Clin Transl Immunol (2021) 10: Chimeric Antigen Receptor T Cell Therapy in Patients With Non-Hodgkin e1268. doi: 10.1002/cti2.1268 Lymphoma. Biol Blood Marrow Transplant (2019) 25:1092–8. doi: 10.1016/ 74. Cieri N, Camisa B, Cocchiarella F, Forcato M, Oliveira G, Provasi E, et al. IL- j.bbmt.2019.02.008 7 and IL-15 Instruct the Generation of Human Memory Stem T Cells From 57. Lyu C, Cui R, Wang J, Mou N, Jiang Y, Li W, et al. Intensive Debulking Naive Precursors. Blood (2013) 121:573–84. doi: 10.1182/blood-2012-05- Chemotherapy Improves the Short-Term and Long-Term Efficacy of Anti- 431718 CD19-CAR-T in Refractory/Relapsed DLBCL With High Tumor Bulk. Front 75. Alvarez-Ferná ndez C, Escribà-Garcia L, Vidal S, Sierra J, Briones J. A Short Oncol (2021) 11:706087. doi: 10.3389/fonc.2021.706087 CD3/CD28 Costimulation Combined With IL-21 Enhance the Generation 58. Roschewski M, Dunleavy K, Pittaluga S, Moorhead M, Pepin F, Kong K, of Human Memory Stem T Cells for Adoptive Immunotherapy. J Trans Med et al. Circulating Tumour DNA and CT Monitoring in Patients With (2016) 14(1):214. doi: 10.1186/s12967-016-0973-y Untreated Diffuse Large B-Cell Lymphoma: A Correlative Biomarker 76. Hinrichs CS, Spolski R, Paulos CM, Gattinoni L, Kerstann KW, Palmer DC, Study. Lancet Oncol (2015) 16:541–9. doi: 10.1016/S1470-2045(15)70106-3 et al. IL-2 and IL-21 Confer Opposing Differentiation Programs to CD8+ T 59. Rossi D, Diop F, Spaccarotella E, Monti S, Zanni M, Rasi S, et al. Diffuse Cells for Adoptive Immunotherapy. Blood (2008) 111:5326–33. doi: 10.1182/ Large B-Cell Lymphoma Genotyping on the Liquid Biopsy. Blood (2017) blood-2007-09-113050 129:1947–57. doi: 10.1182/blood-2016-05-719641 77. Sabatino M, Hu J, Sommariva M, Gautam S, Fellowes V, Hocker JD, et al. 60. Kurtz DM, Green MR, Bratman Sv., Scherer F, Liu CL, Kunder CA, et al. Generation of Clinical-Grade CD19-Specific CAR-Modified CD8+ Memory Noninvasive Monitoring of Diffuse Large B-Cell Lymphoma by Stem Cells for The Treatment of Human B-Cell Malignancies. Blood (2016) Immunoglobulin High-Throughput Sequencing. Blood (2015) 125:3679– 128:519–28. doi: 10.1182/blood-2015-11-683847 87. doi: 10.1182/blood-2015-03-635169 78. Wang X, Popplewell LL, Wagner JR, Naranjo A, Blanchard MS, Mott MR, 61. Frank MJ, Hossain NM, Bukhari A, Dean E, Spiegel JY, Claire GK, et al. et al. Phase 1 Studies of Central Memory-Derived CD19 CAR T-Cell Monitoring of Circulating Tumor DNA Improves Early Relapse Detection Therapy Following Autologous HSCT in Patients With B-Cell NHL. Blood After Axicabtagene Ciloleucel Infusion in Large B-Cell Lymphoma: Results (2016) 127:2980–90. doi: 10.1182/blood-2015-12-686725 of a Prospective Multi-Institutional Trial. J Clin Oncol: Off J Am Soc Clin 79. Xu Y, Zhang M, Ramos CA, Durett A, Liu E, Dakhova O, et al. Closely Oncol (2021) 39:3034–43. doi: 10.1200/JCO.21.00377 Related T-Memory Stem Cells Correlate With In Vivo Expansion of 62. Zhou L, Zhao H, Shao Y, Chen X, Hong R, Wang L, et al. Serial Surveillance CAR.CD19-T Cells and Are Preserved by IL-7 and IL-15. Blood (2014) by Circulating Tumor DNA Profiling After Chimeric Antigen Receptor T 123:3750–9. doi: 10.1182/blood-2014-01-552174 Therapy for the Guidance of R/R Diffuse Large B Cell Lymphoma Precise 80. Fraietta JA, Lacey SF, Orlando EJ, Pruteanu-Malinici I, Gohil M, Lundh S, Treatment. J Cancer (2021) 12:5423–31. doi: 10.7150/jca.60390 et al. Determinants of Response and Resistance to CD19 Chimeric Antigen 63. Lanzavecchia A, Sallusto F. Progressive Differentiation and Selection of the Receptor (CAR) T Cell Therapy of Chronic Lymphocytic Leukemia. Nat Fittest in the Immune Response. Nat Rev Immunol (2002) 2:982–7. Med (2018) 24:563–71. doi: 10.1038/s41591-018-0010-1 doi: 10.1038/nri959 81. Deng Q, Han G, Puebla-Osorio N, Ma MCJ, Strati P, Chasen B, et al. 64. Klebanoff CA, Gattinoni L, Palmer DC, Muranski P, Ji Y, Hinrichs CS, et al. Characteristics of Anti-CD19 CAR T Cell Infusion Products Associated Determinants of Successful CD8 + T-Cell Adoptive Immunotherapy for With Efficacy and Toxicity in Patients With Large B Cell Lymphomas. Nat Large Established Tumors in Mice. Clin Cancer Res (2011) 17(16) 5343–52. Med (2020) 26:1878–87. doi: 10.1038/s41591-020-1061-7 doi: 10.1158/1078-0432.CCR-11-0503 82. Jacobson C, Locke FL, Ghobadi A, Miklos DB, Lekakis LJ, Oluwole OO, et al. 65. Gattinoni L, Lugli E, Ji Y, Pos Z, Paulos CM, Quigley MF, et al. A Human Long-Term (≥4 Year and ≥5 Year) Overall Survival (OS) By 12- and 24- Memory T Cell Subset With Stem Cell-Like Properties. Nat Med (2011) Month Event-Free Survival (EFS): An Updated Analysis of ZUMA-1, the 17:1290–7. doi: 10.1038/nm.2446 Pivotal Study of Axicabtagene Ciloleucel (Axi-Cel) in Patients (Pts) With 66. Gattinoni L, Speiser DE, Lichterfeld M, Bonini C. T Memory Stem Cells in Refractory Large B-Cell Lymphoma (LBCL). Blood (2021) 138:1764–4. Health and Disease. Nat Med (2017) 23:18–27. doi: 10.1038/nm.4241 doi: 10.1182/blood-2021-148078 67. Lugli E, Gattinoni L, Roberto A, Mavilio D, Price DA, Restifo NP, et al. 83. Fraietta JA, Beckwith KA, Patel PR, Ruella M, Zheng Z, Barrett DM, et al. Identification, Isolation and In Vitro Expansion of Human and Nonhuman Ibrutinib Enhances Chimeric Antigen Receptor T-Cell Engraftment and Primate T Stem Cell Memory Cells. Nat Protoc (2013) 8:33–42. doi: 10.1038/ Efficacy in Leukemia. Blood (2016) 127(9):1117–27. doi: 10.1182/blood- nprot.2012.143 2015-11-679134 68. Cieri N, Oliveira G, Greco R, Forcato M, Taccioli C, Cianciotti B, et al. 84. Gauthier J, Hirayama AV, Purushe J, Hay KA, Lymp J, Li DH, et al. Feasibility Generation of Human Memory Stem T Cells After Haploidentical T-Replete and Efficacy of CD19-Targeted CAR T Cells With Concurrent Ibrutinib for Hematopoietic Stem Cell Transplantation. Blood (2015) 125:2865–74. CLL After Ibrutinib Failure. Blood. American Society of Hematology. Blood doi: 10.1182/blood-2014-11-608539 (2020) 135(19): 1650–60. doi: 10.1182/BLOOD.2019002936 69. Klebanoff CA, Gattinoni L, Torabi-Parizi P, Kerstann K, Cardones AR, 85. Geyer MB, Rivière I, Sé né chal B, Wang X, Wang Y, Purdon TJ, et al. Safety Finkelstein SE, et al. Central Memory Self/Tumor-Reactive CD8+ T Cells and Tolerability of Conditioning Chemotherapy Followed by CD19- Frontiers in Immunology | www.frontiersin.org 16 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure Targeted CAR T Cells for Relapsed/Refractory CLL. JCI Insight (2019) 5(9): 103. Thommen DS, Schumacher TN. T Cell Dysfunction in Cancer. Cancer Cell e122627. doi: 10.1172/jci.insight.122627 (2018) 33:547–62. doi: 10.1016/j.ccell.2018.03.012 86. Klebanoff CA, Crompton JG, Leonardi AJ, Yamamoto TN, Chandran SS, Eil 104. Chong EA, Alanio C, Svoboda J, Nasta SD, Landsburg DJ, Lacey SF, et al. RL, et al. Inhibition of AKT Signaling Uncouples T Cell Differentiation From Pembrolizumab for B-Cell Lymphomas Relapsing After or Refractory to Expansion for Receptor-Engineered Adoptive Immunotherapy. JCI Insight CD19-Directed CAR T-Cell Therapy. Blood (2022) 139:1026–38. (2017) 2(23):e95103. doi: 10.1172/jci.insight.95103 doi: 10.1182/blood.2021012634 87. Raje NS, Shah N, Jagannath S, Kaufman JL, Siegel DS, Munshi NC, et al. 105. Cao Y, Lu W, Sun R, Jin X, Cheng L, He X, et al. Anti-CD19 Chimeric Updated Clinical and Correlative Results From the Phase I CRB-402 Study Antigen Receptor T Cells in Combination With Nivolumab Are Safe and of the BCMA-Targeted CAR T Cell Therapy Bb21217 in Patients With Effective Against Relapsed/Refractory B-Cell Non-Hodgkin Lymphoma. Relapsed and Refractory Multiple Myeloma. Blood (2021) 138:548–8. Front Oncol (2019) 9:767. doi: 10.3389/fonc.2019.00767 doi: 10.1182/blood-2021-146518 106. Gilbert JA, Blaser MJ, Caporaso JG, Jansson JK, v LS, Knight R. Current 88. Kagoya Y, Nakatsugawa M, Yamashita Y, Ochi T, Guo T, Anczurowski M, Understanding of the Human Microbiome. Nat Med (2018) 24:392–400. et al. BET Bromodomain Inhibition Enhances T Cell Persistence and doi: 10.1038/nm.4517 Function in Adoptive Immunotherapy Models. J Clin Invest (2016) 107. Schwabe RF, Jobin C. The Microbiome and Cancer. Nat Rev Cancer (2013) 126:3479–94. doi: 10.1172/JCI86437 13:800–12. doi: 10.1038/nrc3610 89. Kong W, Dimitri A, Wang W, Jung IY, Ott CJ, Fasolino M, et al. BET 108. Viaud S, Saccheri F, Mignot G, Yamazaki T, Daillère R, Hannani D, et al. The Bromodomain Protein Inhibition Reverses Chimeric Antigen Receptor Intestinal Microbiota Modulates the Anticancer Immune Effects of Extinction and Reinvigorates Exhausted T Cells in Chronic Lymphocytic Cyclophosphamide. Science (1979) (2013) 342:971–6. doi: 10.1126/ Leukemia. J Clin Invest (2021) 131:1–16. doi: 10.1172/JCI145459 science.1240537 90. Majzner RG, Mackall CL. Tumor Antigen Escape From CAR T-Cell 109. Daillère R, Vé tizou M, Waldschmitt N, Yamazaki T, Isnard C, Poirier- Therapy. Cancer Discov (2018) 8:1219–26. doi: 10.1158/2159-8290.CD-18- Colame V, et al. Enterococcus Hirae and Barnesiella Intestinihominis 0442 Facilitate Cyclophosphamide-Induced Therapeutic Immunomodulatory 91. Frey N v, Shaw PA, Hexner EO, Pequignot E, Gill S, Luger SM, et al. Effects. Immunity (2016) 45:931–43. doi: 10.1016/j.immuni.2016.09.009 Optimizing Chimeric Antigen Receptor T-Cell Therapy for Adults With 110. Abid MB, Shah NN, Maatman TC, Hari PN. Gut Microbiome and CAR-T Acute Lymphoblastic Leukemia. J Clin Oncol: Off J Am Soc Clin Oncol (2020) Therapy. Exp Hematol Oncol (2019) 8:1–10. doi: 10.1186/s40164-019-0155-8 38:415–22. doi: 10.1200/JCO.19.01892 111. Peled JU, Gomes ALC, Devlin SM, Littmann ER, Taur Y, Sung AD, et al. 92. Maude SL, Laetsch TW, Buechner J, Rives S, Boyer M, Bittencourt H, et al. Microbiota as Predictor of Mortality in Allogeneic Hematopoietic-Cell Tisagenlecleucel in Children and Young Adults With B-Cell Lymphoblastic Transplantation. New Engl J Med (2020) 382:822–34. doi: 10.1056/ Leukemia. N Engl J Med (2018) 378:439–48. doi: 10.1056/NEJMoa1709866 nejmoa1900623 93. Davila ML, Riviere I, Wang X, Bartido S, Park J, Curran K, et al. Efficacy and 112. Smith M, Dai A, Ghilardi G, Amelsberg K v., Devlin SM, Pajarillo R, et al. Toxicity Management of 19-28z CAR T Cell Therapy in B Cell Acute Gut Microbiome Correlates of Response and Toxicity Following Anti-CD19 Lymphoblastic Leukemia. Sci Transl Med (2014) 6:224ra25. doi: 10.1126/ CAR T Cell Therapy. Nat Med (2022) 28:713–23. doi: 10.1038/s41591-022- scitranslmed.3008226 01702-9 94. Wudhikarn K, Flynn JR, Rivière I, Gönen M, Wang X, Senechal B, et al. 113. Gopalakrishnan V, Spencer CN, Nezi L, Reuben A, Andrews MC, Karpinets Interventions and Outcomes of Adult Patients With B-ALL Progressing Tv, et al. Gut Microbiome Modulates Response to Anti-PD-1 After CD19 Chimeric Antigen Receptor T-Cell Therapy. Blood (2021) Immunotherapy in Melanoma Patients. Science (1979) (2018) 359:97–103. 138:531–43. doi: 10.1182/blood.2020009515 doi: 10.1126/science.aan4236 95. Spiegel JY, Dahiya S, Jain MD, Tamaresis J, Nastoupil LJ, Jacobs MT, et al. 114. Routy B, le Chatelier E, Derosa L, Duong CPM, Alou MT, Daillère R, et al. Gut Outcomes of Patients With Large B-Cell Lymphoma Progressing After Microbiome Influences Efficacy of PD-1-Based Immunotherapy Against Axicabtagene Ciloleucel Therapy. Blood (2021) 137:1832–5. doi: 10.1182/ Epithelial Tumors. Science (1979) (2018) 359:91–7. doi: 10.1126/science.aan3706 blood.2020006245 115. Schluter J, Peled JU, Taylor BP, Markey KA, Smith M, Taur Y, et al. The Gut 96. Spiegel JY, Patel S, Muffly L, Hossain NM, Oak J, Baird JH, et al. CAR T Cells Microbiota is Associated With Immune Cell Dynamics in Humans. Nature With Dual Targeting of CD19 and CD22 in Adult Patients With Recurrent (2020) 588:303–7. doi: 10.1038/s41586-020-2971-8 or Refractory B Cell Malignancies: A Phase 1 Trial. Nat Med (2021) 27:1419– 116. Chow VA, Gopal AK, Maloney DG, Turtle CJ, Smith SD, Ujjani CS, et al. 31. doi: 10.1038/s41591-021-01436-0 Outcomes of Patients With Large B-Cell Lymphomas and Progressive 97. Zah E, Lin M-Y, Silva-Benedict A, Jensen MC, Chen YY. T Cells Expressing Disease Following CD19-Specific CAR T-Cell Therapy. Am J Hematol CD19/CD20 Bispecific Chimeric Antigen Receptors Prevent Antigen Escape (2019) 94:E209–13. doi: 10.1002/ajh.25505 by Malignant B Cells. Cancer Immunol Res (2016) 4:498–508. doi: 10.1158/ 117. Sigmund AM, Denlinger N, Huang Y, Bond D, Voorhees T, Bajwa A, et al. 2326-6066.CIR-15-0231 Assessment of Salvage Regimens Post CAR-T Cell Therapy for Patients With 98. Sotillo E, Barrett DM, Black KL, Bagashev A, Oldridge D, Wu G, et al. Diffuse Large B-Cell Lymphoma. Transplant Cell Ther (2022) 28(6):342.e1– Convergence of Acquired Mutations and Alternative Splicing of CD19 342.e5. doi: 10.1016/j.jtct.2022.02.021 Enables Resistance to CART-19 Immunotherapy. Cancer Discovery (2015) 118. Salles G, Długosz-Danecka M, Ghesquières H, Jurczak W. Tafasitamab for the 5:1282–95. doi: 10.1158/2159-8290.CD-15-1020 Treatment of Relapsed or Refractory Diffuse Large B-Cell Lymphoma. Expert 99. Ruella M, Xu J, Barrett DM, Fraietta JA, Reich TJ, Ambrose DE, et al. Opin Biol Ther (2021) 21:455–63. doi: 10.1080/14712598.2021.1884677 Induction of Resistance to Chimeric Antigen Receptor T Cell Therapy by 119. Jurczak W, Zinzani PL, Gaidano G, Goy A, Provencio M, Nagy Z, et al. Phase Transduction Of a Single Leukemic B Cell. Nat Med (2018) 24:1499–503. IIa Study of the CD19 Antibody MOR208 in Patients With Relapsed or doi: 10.1038/s41591-018-0201-9 Refractory B-Cell Non- Hodgkin’s Lymphoma. Ann Oncol (2018) 29:1266– 100. Xue Q, Bettini E, Paczkowski P, Ng C, Kaiser A, McConnell T, et al. Single- 72. doi: 10.1093/annonc/mdy056 Cell Multiplexed Cytokine Profiling of CD19 CAR-T Cells Reveals a Diverse 120. Salles G, Duell J, Gonzá lez Barca E, Tournilhac O, Jurczak W, Liberati AM, Landscape of Polyfunctional Antigen-Specific Response. J Immunother et al. Tafasitamab Plus Lenalidomide in Relapsed or Refractory Diffuse Large Cancer (2017) 5:85. doi: 10.1186/s40425-017-0293-7 B-Cell Lymphoma (L-MIND): A Multicentre, Prospective, Single-Arm, 101. Rossi J, Paczkowski P, Shen Y-W, Morse K, Flynn B, Kaiser A, et al. Phase 2 Study. Lancet Oncol (2020) 21:978–88. doi: 10.1016/S1470-2045 Preinfusion Polyfunctional Anti-CD19 Chimeric Antigen Receptor T Cells (20)30225-4 Are Associated With Clinical Outcomes in NHL. Blood (2018) 132:804–14. 121. Duell J, Maddocks KJ, Gonzá lez-Barca E, Jurczak W, Liberati AM, de Vos S, doi: 10.1182/blood-2018-01-828343 et al. Long-Term L-MIND Study Outcomes of Tafasitamab From the 102. Tran MA, Bhardwaj N. Exhausted T Cell Phenotypes Depend on TCR Signal (MOR208) Phase II Plus Lenalidomide in Patients With Relapsed or Strength. Nat Rev Immunol (2022) 22(4):206. doi: 10.1038/s41577-022- Refractory Diffuse Large B-Cell Lymphoma. Haematologica (2021) 00696-2 106:2417–26. doi: 10.3324/haematol.2020.275958 Frontiers in Immunology | www.frontiersin.org 17 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure 122. Tabbara N, Gaut D, Oliai C, Lewis T, de Vos S. Anti-CD19 CAR T-Cell Lymphoma With Favorable Prognosis and Distinct Gene Expression Therapy Remission Despite Prior Anti-CD19 Antibody Tafasitamab in Signature: A Report From the International DLBCL Rituximab-CHOP Relapsed/Refractory DLBCL. Leukemia Res Rep (2021) 16:100260. Consortium Program Study. Blood (2013) 121:2715–24. doi: 10.1182/ doi: 10.1016/j.lrr.2021.100260 blood-2012-10-461848 123. Thomas A, Teicher BA, Hassan R. Antibody–drug Conjugates for Cancer 139. Bartlett NL, Smith MR, Siddiqi T, Advani RH, O’Connor OA, Sharman JP, Therapy. Lancet Oncol (2016) 17:e254–62. doi: 10.1016/S1470-2045(16) et al. Brentuximab Vedotin Activity in Diffuse Large B-Cell Lymphoma With 30030-4 C D 3 0 U n d e te ct a b l e b y Vi s u a l A s s es s m e n t o f C o n v e n ti o n a l 124. Liebers N, Duell J, Fitzgerald D, Kerkhoff A, Noerenberg D, Kaebisch E, et al. Immunohistochemistry. Leukemia Lymphoma (2017) 58:1607–16. Polatuzumab Vedotin as a Salvage and Bridging Treatment in Relapsed or doi: 10.1080/10428194.2016.1256481 Refractory Large B-Cell Lymphomas. Blood Adv (2021) 5:2707–16. 140. Li D, Poon KA, Yu S, Dere R, Go M, Lau J, et al. DCDT2980S , an Anti- doi: 10.1182/bloodadvances.2020004155 CD22-Monomethyl Auristatin E Antibody – Drug Conjugate , Is a Potential 125. Polson AG, Yu SF, Elkins K, Zheng B, Clark S, Ingle GS, et al. Antibody- Treatment for Non-Hodgkin Lymphoma. Mol Cancer Ther (2013) 12:1255– Drug Conjugates Targeted to CD79 for the Treatment of non-Hodgkin 65. doi: 10.1158/1535-7163.MCT-12-1173 Lymphoma. Blood (2007) 110:616–23. doi: 10.1182/blood-2007-01- 141. Yu S, Zheng B, Go M, Lau J, Spencer S, Raab H, et al. A Novel Anti-CD22 066704 Anthracycline-Based Antibody – Drug Conjugate ( ADC ) That Overcomes 126. Sehn LH, Herrera AF, Flowers CR, Kamdar MK, McMillan A, Hertzberg M, Resistance to Auristatin-Based ADCs. Clin Cancer Res (2015) 4:3298–306. et al. Polatuzumab Vedotin in Relapsed or Refractory Diffuse Large B-Cell doi: 10.1158/1078-0432.CCR-14-2035 Lymphoma. J Clin Oncol (2020) 38:155–65. doi: 10.1200/JCO.19.00172 142. Advani RH, Lebovic D, Chen A, Brunvand M, Goy A, Chang JE, et al. Phase I 127. Sehn LH, Hertzberg M, Opat S, Herrera AF, Assouline S, Flowers CR, et al. Study of the Anti-CD22 Antibody-Drug Conjugate Pinatuzumab Vedotin Polatuzumab Vedotin Plus Bendamustine and Rituximab in Relapsed/ With/Without Rituximab in Patients With Relapsed/Refractory B-Cell Non- Refractory DLBCL: Survival Update and New Extension Cohort Data. Hodgkin Lymphoma. Clin Cancer Res : an Off J Am Assoc Cancer Res (2017) Blood Adv (2022) 6:533–43. doi: 10.1182/bloodadvances.2021005794 23:1167–76. doi: 10.1158/1078-0432.CCR-16-0772 128. Dimou M, Papageorgiou SG, Stavroyianni N, Katodritou E, Tsirogianni M, 143. Morschhauser F, Flinn IW, Advani R, Sehn LH, Diefenbach C, Kolibaba K, Kalpadakis C, et al. Real-Life Experience With the Combination of et al. Polatuzumab Vedotin or Pinatuzumab Vedotin Plus Rituximab in Polatuzumab Vedotin, Rituximab, and Bendamustine in Aggressive B-Cell Patients With Relapsed or Refractory non-Hodgkin Lymphoma: Final Lymphomas. Hematological Oncol (2021) 39:336–48. doi: 10.1002/hon.2842 Results From a Phase 2 Randomised Study (ROMULUS). Lancet 129. Younes A, Kim S, Romaguera J, Copeland A, Farial SDC, Kwak LW, et al. Haematol (2019) 6:e254–65. doi: 10.1016/S2352-3026(19)30026-2 Phase I Multidose-Escalation Study of the Anti-CD19 Maytansinoid 144. Schuster SJ. Bispecific Antibodies for the Treatment of Lymphomas: Immunoconjugate SAR3419 Administered by Intravenous Infusion Every Promises and Challenges. Hematological Oncol (2021) 39:113–6. 3 Weeks to Patients With Relapsed/Refractory B-Cell Lymphoma. J Clin doi: 10.1002/hon.2858 Oncol (2012) 30:2776–82. doi: 10.1200/JCO.2011.39.4403 145. Brinkmann U, Kontermann RE. The Making of Bispeci Fi C Antibodies. 130. Trneny M, Verhoef G, Dyer MJS, Yehuda Db, Patti C, Canales M, et al. A MAbs (2017) 9(2):182–212. doi: 10.1080/19420862.2016.1268307 Phase Ii Multicenter Study of the Anti-CD19 Antibody Drug Conjugate 146. Viardot A, Goebeler ME, Hess G, Neumann S, Pfreundschuh M, Adrian N, Coltuximab Ravtansine (SAR3419) in Patients With Relapsed or Refractory et al. Phase 2 Study of the Bispecific T-Cell Engager (Bite) Antibody Diffuse Large B-Cell Lymphoma Previously Treated With Rituximab-Based Blinatumomab in Relapsed/Refractory Diffuse Large B-Cell Lymphoma. Immunotherapy. . Haematologica (2018) 103:1351–8. doi: 10.3324/ Blood (2016) 127:1410–6. doi: 10.1182/blood-2015-06-651380 haematol.2017.168401 147. Klinger M, Brandl C, Zugmaier G, Hijazi Y, Bargou RC, Topp MS, et al. 131. Zammarchi F, Corbett S, Adams L, Tyrer PC, Kiakos K, Janghra N, et al. Immunopharmacologic Response of Patients With B-Lineage Acute ADCT-402, A PBD Dimer–Containing Antibody Drug Conjugate Targeting Lymphoblastic Leukemia to Continuous Infusion of T Cell-Engaging CD19-Expressing Malignancies. Blood (2018) 131:1094–105. doi: 10.1182/ CD19/CD3-Bispecific BiTE Antibody Blinatumomab. Blood (2012) blood-2017-10-813493 119:6226–33. doi: 10.1182/blood-2012-01-400515 132. Kahl BS, Hamadani M, Radford J, Carlo-Stella C, Caimi P, Reid E, et al. A 148. Coyle L, Morley NJ, Rambaldi A, Mason KD, Verhoef G, Furness CL, et al. Phase I Study of ADCT-402 (Loncastuximab Tesirine), a Novel Open-Label, Phase 2 Study of Blinatumomab as Second Salvage Therapy in Pyrrolobenzodiazepine-Based Antibody–Drug Conjugate, in Relapsed/ Adults With Relapsed/Refractory Aggressive B-Cell non-Hodgkin Refractory B-Cell non-Hodgkin Lymphoma. Clin Cancer Res (2019) Lymphoma. Leukemia Lymphoma (2020) 61:2103–12. doi: 10.1080/ 25:6986–94. doi: 10.1158/1078-0432.CCR-19-0711 10428194.2020.1759055 133. Caimi PF, Ai W, Alderuccio JP, Ardeshna KM, Hamadani M, Hess B, et al. 149. Hutchings M, Morschhauser F, Iacoboni G, Carlo-Stella C, Offner FC, Loncastuximab Tesirine in Relapsed or Refractory Diffuse Large B-Cell Sureda A, et al. Glofitamab, a Novel, Bivalent CD20-Targeting T-Cell- Lymphoma (LOTIS-2): A Multicentre, Open-Label, Single-Arm, Phase 2 Engaging Bispecific Antibody, Induces Durable Complete Remissions in Trial. Lancet Oncol (2021) 22:790–800. doi: 10.1016/S1470-2045(21)00139-X Relapsed or Refractory B-Cell Lymphoma: A Phase I Trial. J Clin Oncol 134. Caimi PF, Ardeshna KM, Reid E, Ai W, Lunning M, Zain J, et al. The (2021) 39:1959–70. doi: 10.1200/JCO.20.03175 AntiCD19 Antibody Drug Immunoconjugate Loncastuximab Achieves 150. Hutchings M, Sureda A, Terol MJ, Bosch Albareda F, Corradini P, Larsen TS, Responses in DLBCL Relapsing After AntiCD19 CAR-T Cell Therapy. et al. Glofitamab (Glofit) in Combination With Polatuzumab Vedotin (Pola): Clin Lymphoma Myeloma Leukemia (2022) 22(5):e335–9. doi: 10.1016/ Phase Ib/II Preliminary Data Support Manageable Safety and Encouraging j.clml.2021.11.005 Efficacy in Relapsed/Refractory (R/R) Diffuse Large B-Cell Lymphoma 135. Francisco JA, Cerveny CG, Meyer DL, Mixan BJ, Klussman K, Chace DF, (DLBCL). Blood (2021) 138:525. doi: 10.1182/blood-2021-148359 et al. Cac10-vcMMAE, an Anti-CD30-Monomethyl Auristatin E Conjugate 151. Sun LL, Ellerman D, Mathieu M, Hristopoulos M, Chen X, Li Y, et al. Anti-CD20/ With Potent and Selective Antitumor Activity. Blood (2003) 102:1458–65. CD3 T Cell-Dependent Bispecific Antibody for the Treatment of B Cell Malignancies. doi: 10.1182/blood-2003-01-0039 Sci Trans Med (2015) 7(287):287ra70. doi: 10.1126/scitranslmed.aaa4802 136. Jacobsen ED, Sharman JP, Oki Y, Advani RH, Winter JN, Bello CM, et al. 152. Budde LE, Assouline S, Sehn LH, Schuster SJ, Yoon SS, Yoon DH, et al. Brentuximab Vedotin Demonstrates Objective Responses in a Phase 2 Study Single-Agent Mosunetuzumab Shows Durable Complete Responses in of Relapsed/Refractory DLBCL With Variable CD30 Expression. Blood Patients With Relapsed or Refractory B-Cell Lymphomas: Phase I Dose- (2015) 125:1394–402. doi: 10.1182/blood-2014-09-598763 Escalation Study. J Clin Oncol (2022) 40:481–91. doi: 10.1200/JCO.21.00931 137. Slack GW, Steidl C, Sehn LH, Gascoyne RD. CD30 Expression in De Novo 153. Bannerji R, Allan JN, Arnason JE, Brown JR, Advani R, Ansell SM, et al. Diffuse Large B-Cell Lymphoma: A Population-Based Study From British Odronextamab (REGN1979), a Human CD20 X CD3 Bispecific Antibody, Columbia. Br J Haematol (2014) 167:608–17. doi: 10.1111/bjh.13085 Induces Durable, Complete Responses in Patients With Highly Refractory B- 138. Hu S, Xu-Monette ZY, Balasubramanyam A, Manyam GC, Visco C, Tzankov Cell Non-Hodgkin Lymphoma, Including Patients Refractory to CAR T A, et al. CD30 Expression Defines a Novel Subgroup of Diffuse Large B-Cell Therapy. Blood (2020) 136:42–3. doi: 10.1182/blood-2020-136659 Frontiers in Immunology | www.frontiersin.org 18 July 2022 | Volume 13 | Article 904497 Caballero et al. DLBCL Treatment After CART19 Failure 154. Engelberts PJ, Hiemstra IH, de Jong B, Schuurhuis DH, Meesters J, Beltran Practice in Europe, 2019. Bone Marrow Transplant (2019) 54:1525–52. Hernandez I, et al. DuoBody-CD3xCD20 Induces Potent T-Cell-Mediated doi: 10.1038/s41409-019-0516-2 Killing of Malignant B Cells in Preclinical Models and Provides 161. Dreger P, Fenske TS, Montoto S, Pasquini MC, Sureda A, Hamadani M. Opportunities for Subcutaneous Dosing. EBioMedicine (2020) 52:102625. Cellular Immunotherapy for Refractory Diffuse Large B Cell Lymphoma in doi: 10.1016/j.ebiom.2019.102625 the Chimeric Antigen Receptor-Engineered T Cell Era: Still a Role for 155. Hutchings M, Mous R, Clausen MR, Johnson P, Linton KM, Chamuleau MED, Allogeneic Transplantation? Biol Blood Marrow Transplant (2020) 26:e77– et al. Dose Escalation of Subcutaneous Epcoritamab in Patients With Relapsed or 85. doi: 10.1016/j.bbmt.2019.12.771 Refractory B-Cell non-Hodgkin Lymphoma: An Open-Label, Phase 1/2 Study. 162. Fried S, Danylesko I, Yerushalmi R, Shem-Tov N, Shouval R, Fein JA, et al. Lancet (2021) 398:1157–69. doi: 10.1016/S0140-6736(21)00889-8 Encouraging Survival and High Rates of Toxicity: Allogeneic Hematopoietic 156. Wang C, Shi F, Liu Y, Zhang Y, Dong L, Li X, et al. Anti-PD-1 Antibodies as Cell Transplantation After Anti-CD19 Chimeric Antigen Receptor T-Cell a Salvage Therapy for Patients With Diffuse Large B Cell Lymphoma Who Therapy in Aggressive Lymphoma Patients. Blood (2021) 138:910. Progressed/Relapsed After CART19/20 Therapy. J Hematol Oncol (2021) doi: 10.1182/blood-2021-147148 14:1–6. doi: 10.1186/s13045-021-01120-3 157. Siddiqi T, Abramson JS, Lee HJ, Schuster S, Hasskarl J, Montheard S, et al. Conflict of Interest: The authors declare that the research was conducted in the Safety Of Lisocabtagene Maraleucel Given With Durvalumab In Patients absence of any commercial or financial relationships that could be construed as a With Relapsed/Refractory Aggressive B-Cell Non Hodgkin Lymphoma: First potential conflict of interest. Results From The Platform Study. Hematological Oncol (2019) 37:171–2. doi: 10.1002/hon.128_2629 Publisher’s Note: All claims expressed in this article are solely those of the authors 158. Topp MS, Eradat H, Florschütz A, Hochhaus A, Wrobel T, Walewski J, et al. and do not necessarily represent those of their affiliated organizations, or those of Anti-CD20–atezolizumab–polatuzumab Vedotin in Relapsed/Refractory the publisher, the editors and the reviewers. Any product that may be evaluated in Follicular and Diffuse Large B-Cell Lymphoma. J Cancer Res Clin Oncol this article, or claim that may be made by its manufacturer, is not guaranteed or (2022). doi: 10.1007/s00432-021-03847-5 endorsed by the publisher. 159. Kalakonda N, Maerevoet M, Cavallo F, Follows G, Goy A, Vermaat JSP, et al. Selinexor in Patients With Relapsed or Refractory Diffuse Large B-Cell Copyright © 2022 Caballero, Escribà-Garcia, Alvarez-Fernań dez and Briones. This is Lymphoma (SADAL): A Single-Arm, Multinational, Multicentre, Open- an open-access article distributed under the terms of the Creative Commons Label, Phase 2 Trial. Lancet Haematol (2020) 7:e511–22. doi: 10.1016/ Attribution License (CC BY). The use, distribution or reproduction in other forums S2352-3026(20)30120-4 is permitted, provided the original author(s) and the copyright owner(s) are credited 160. Duarte RF, Labopin M, Bader P, Basak GW, Bonini C, Chabannon C, et al. and that the original publication in this journal is cited, in accordance with accepted Indications for Haematopoietic Stem Cell Transplantation for academic practice. No use, distribution or reproduction is permitted which does not Haematological Diseases, Solid Tumours and Immune Disorders: Current comply with these terms. Frontiers in Immunology | www.frontiersin.org 19 July 2022 | Volume 13 | Article 904497