Leukemia & Lymphoma ISSN: 1042-8194 (Print) 1029-2403 (Online) Journal homepage: https://www.tandfonline.com/loi/ilal20 A prospective non-interventional study on the impact of transfusion burden and related iron toxicity on outcome in myelodysplastic syndromes undergoing allogeneic hematopoietic cell transplantation Eline M.P. Cremers, Theo de Witte, Liesbeth de Wreede, Diderik-Jan Eikema, Linda Koster, Anja van Biezen, Jürgen Finke, Gerard Socié, Dietrich Beelen, Johan Maertens, Arnon Nagler, Guido Kobbe, Dimitris Ziagkos, Maija Itälä-Remes, Tobias Gedde-Dahl, Jorge Sierra, Dietger Niederwieser, Per Ljungman, Yves Beguin, Zubeyde Nur Ozkurt, Achilles Anagnostopoulos, Pavel Jindra, Marie Robin & Nicolaus Kröger To cite this article: Eline M.P. Cremers, Theo de Witte, Liesbeth de Wreede, Diderik-Jan Eikema, Linda Koster, Anja van Biezen, Jürgen Finke, Gerard Socié, Dietrich Beelen, Johan Maertens, Arnon Nagler, Guido Kobbe, Dimitris Ziagkos, Maija Itälä-Remes, Tobias Gedde- Dahl, Jorge Sierra, Dietger Niederwieser, Per Ljungman, Yves Beguin, Zubeyde Nur Ozkurt, Achilles Anagnostopoulos, Pavel Jindra, Marie Robin & Nicolaus Kröger (2019) A prospective non- interventional study on the impact of transfusion burden and related iron toxicity on outcome in myelodysplastic syndromes undergoing allogeneic hematopoietic cell transplantation, Leukemia & Lymphoma, 60:10, 2404-2414, DOI: 10.1080/10428194.2019.1594215 To link to this article: https://doi.org/10.1080/10428194.2019.1594215 © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. View supplementary material Published online: 18 Apr 2019. Submit your article to this journal Article views: 181 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=ilal20 LEUKEMIA & LYMPHOMA 2019, VOL. 60, NO. 10, 2404–2414 https://doi.org/10.1080/10428194.2019.1594215 ORIGINAL ARTICLE A prospective non-interventional study on the impact of transfusion burden and related iron toxicity on outcome in myelodysplastic syndromes undergoing allogeneic hematopoietic cell transplantation Eline M.P. Cremersa , Theo de Witteb, Liesbeth de Wreedec, Diderik-Jan Eikemad, Linda Kostere, Anja van Biezene, Ju€rgen Finkef, Gerard Socieg, Dietrich Beelenh, Johan Maertensi, Arnon Naglerj, Guido Kobbe , Dimitris Ziagkosd, Maija It€al€a-Remesl, Tobias Gedde-Dahlm, Jorge Sierran , k Dietger Niederwiesero, Per Ljungmanp, Yves Beguinq, Zubeyde Nur Ozkurtr, Achilles Anagnostopouloss, Pavel Jindrat, Marie Robing and Nicolaus Kro €geru a Department of Hematology, VU University Medical Centre, Amsterdam, The Netherlands; bRadboud University Medical Centre, Nijmegen, The Netherlands; cLeiden University Medical Centre, Leiden, The Netherlands; dEBMT Statistical Unit Data Office Leiden, Leiden, The Netherlands; eEBMT Data Office Leiden, Leiden, The Netherlands; fDepartment of Hematology/Oncology & Stem Cell Transplantation, University of Freiburg, Freiburg, Germany; gHospital St. Louis, Paris, France; hUniversity Hospital, Essen, Germany; i University Hospital Gasthuisberg, Leuven, Belgium; jChaim Sheba Medical Center, Tel-Hashomer, Israel; kDepartment of Hematology, Oncology and Clinical Immunology, Heinrich Heine Universitaet, D€usseldorf, Germany; lHUCH Comprehensive Cancer Center, Helsinki, Finland; mOslo University Hospital, Rikshospitalet, Oslo, Norway; nHospital Santa Creu i Sant Pau, Barcelona, Spain; oUniversity Hospital Leipzig, Leipzig, Germany; pKarolinska University Hospital, Stockholm, Sweden; qDepartmrnt of Hematology and Oncology, University of Liege, Liege, Belgium; rFaculty of Medicine, Gazi University, Ankara, Turkey; sGeorge Papanicolaou General Hospital, Thessaloniki, Greece; tCharles University Hospital, Pilsen, Czech Republic; uUniversity Hospital Eppendorf, Hamburg, Germany ABSTRACT ARTICLE HISTORY Most myelodysplastic syndromes (MDS)-patients receive multiple red blood cell transfusions Received 15 July 2018 (RBCT). Transfusions may cause iron-related toxicity and mortality, influencing outcome after Accepted 1 March 2019 allogeneic HSCT. This prospective non-interventional study evaluated 222 MDS and CMML KEYWORDS patients undergoing HSCT. Overall survival (OS), relapse-free survival (RFS), non-relapse mortality MDS; allogeneic stem cell (NRM), and relapse incidence (RI) at 36 months were 52%, 44%, 25%, and 31%, respectively. transplantation; transfu- Age, percentage of marrow blasts and severe comorbidities impacted OS. RFS was significantly sions; phlebotomies; associated with RBCT burden prior to HSCT (HR: 1.7; p ¼ .02). High ferritin levels had a significant chelation therapy negative impact on OS and RI, but no impact on NRM. Administration of iron chelation therapy prior to HSCT did not influence the outcome, but early iron reduction after HSCT (started before 6 months) improved RFS significantly after transplantation (56% in the control group vs. 90% in the treated group, respectively; p ¼ .04). This study illustrates the impact of RBCT and related parameters on HSCT-outcome. Patients with an expected prolonged survival after transplant- ation may benefit from early iron reduction therapy after transplantation. Introduction more frail patients with MDS [5,6]. Many parameters such as age, comorbidity, advanced disease stage, and Allogeneic hematopoietic stem cell transplantation cytogenetic risk category according to the (revised)- (HSCT) is the most potent curative therapeutic option in International Prognostic Scoring system (IPSS-R) have patients with myelodysplastic syndromes (MDS) [1]. Due been reported to impact treatment outcome [4,7–10]. to high treatment-related morbidity and mortality, com- Around 80% of patients with MDS present with anemia bined with a high relapse risk, the current long-term and many of these patients receive multiple red blood overall survival rate is around 35% [2–4]. Non-relapse cell transfusions (RBCT) during the course of their dis- mortality (NRM) has decreased after the introduction of ease [11]. RBCT and associated iron overload may cause reduced intensity regimens (RIC) for the elderly and toxicity and mortality, and influence outcome after CONTACT Eline M. P. Cremers e.cremers@vumc.nl Department of Hematology, VU University Medical Center, 1081 HV Amsterdam, Amsterdam, The Netherlands A study on behalf of the MDS subcommittee of the chronic malignancies working party of the European Society for Blood and Marrow Transplantation. Supplemental data for this article can be accessed here. ß 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by- nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. IRON TOXICITY IN MDS PATIENTS UNDERGOING UPFRONT HSCT 2405 HSCT [12–15]. Most studies are retrospective and selec- Declaration of Helsinki and written informed consent tion bias and lack of detailed data about interventions, was obtained from each participating patient. Trial outcome, and potentially confounding risk factors might registered at Clinicaltrial.gov Identifier: 842205547. have influenced conclusions. Retrospective data were collected by survey at diag- The Chronic Malignancies Working Party (CMWP) of nosis, and prospectively at transplantation and 6 weeks, the EBMT performed a large prospective, non-interven- 100 days, 6 months, 1 year, and annually thereafter. tional study to evaluate prognostic pre-transplant fac- Missing data were collected by follow-up surveys. Based tors in MDS and chronic myelomonocytic leukemia on the study objectives the following variables were col- (CMML). The primary objective of this study was to lected: age, gender, comorbidities, WHO classification, evaluate the relation between iron toxicity and treat- cytogenetic characteristics according to IPSS-R, number ment-related mortality after allogeneic HSCT in adult of transfusions, ferritin levels, hemoglobin levels, C-react- MDS and CMML patients. We excluded patients ive protein (CRP), donor type, female-donor/male recipi- treated with intensive chemotherapy from this study, ent vs. other combinations, interval diagnosis, and because previous intensive chemotherapy is expected HSCT, intensity of HSCT conditioning, acute and chronic to have an impact on important pre-HSCT co-variables, graft vs. host disease (GvHD), and data concerning treat- including advanced stages of disease (relapsed or ment with iron chelation or phlebotomy. refractory), more co-morbid conditions and poorer Primary end-points were overall survival (OS), general condition. This approach is expected to be relapse-free survival (RFS), relapse incidence (RI), and associated with a reduced pretreatment related mor- non-relapse mortality (NRM), evaluated at 36 months bidity, and a reduction of the interval between diag- after transplant. The median follow-up was estimated nosis and HSCT. Secondary objectives were (i) using the reverse Kaplan–Meier method. Additionally, description of treatment outcomes defined by NRM, acute GvHD grade I–II and III–IV, and limited and exten- OS, relapse incidence (RI) and relapse-free survival sive chronic GvHD were evaluated at 100 days and (RFS); (ii) impact of RBCT and surrogate iron markers 36 months after transplant, respectively. OS and RFS that may reflect iron burden on treatment outcome. were estimated using the Kaplan–Meier product limit The final objective was to evaluate the impact of iron estimation method, and differences in subgroups were reduction therapy prior and post HSCT on the out- assessed by the Log-Rank test. Cumulative incidences come after HSCT. of relapse and NRM, were analyzed in a competing risks framework. The cumulative incidences of acute GvHD grade I–II and III–IV were estimated as competing risks, Patients and methods considering as competing for event death before Two hundred twenty-two adult (age 18 years at aGvHD. The cumulative incidences of limited and HSCT) patients with de-novo MDS, AML-MDS with extensive cGvHD were estimated equivalently. 20–30% marrow blasts (formerly RAEBt) or patients Subgroup differences were assessed by Gray’s test. Cox with CMML who received upfront HSCT after bone proportional hazards regression was used to assess the marrow ablative or reduced intensity regimens were impact of potential risk factors in univariable and multi- included prospectively between January 2009 and variable analyses. Multivariable analyses of RI and NRM January 2014. Patients had an ECOG performance sta- were performed using Cox cause-specific hazards mod- tus between 0 and 2. Exclusion criteria included previ- els. The impact of post-transplant iron reduction ther- ous intensive anti-leukemic chemotherapy, patients apy was investigated using landmark analyses at 6, 12 with juvenile CMML, patients with therapy-related and 24 months. The landmark population was defined MDS, AML, or CMML after treatment with immunosup- as patients alive (event ¼ death) and event-free pressive or cytotoxic treatment for a non-myeloid (event ¼ death and/or relapse) at the respective land- malignancy, patients who had received auto-HSCT, mark time points. All p values were two-sided and candidates for cord blood HSCT or syngeneic HSCT, p < .05 was considered significant. inadequate renal function (ECC <60 ml/min and/or creatinine >2.5 times upper limit of normal value), Results inadequate hepatic function (transaminases >2.5 times Demographic and transplantation data upper limit of normal value), history of seizures, preg- nancy, and women of child-bearing potential and not The study included 181 patients with MDS, 16 patients using adequate contraceptives, uncontrolled hyperten- with AML-MDS, and 25 patients with CMML from 29 sion. The research was conducted according to the European transplant centers (for details, see Table 1). 2406 E. M. P. CREMERS ET AL. Table 1. Demographic data and estimates of survival outcomes and cumulative incidences. N OS NRM RI RFS All patients 222 52% (45–59%) 25% (19–32%) 31% (24–37%) 44% (37–51%) Median age (95% CIa) / HR 59.3 (52.2–64.4) 1.4 (1.1–1.8) (0.002) 1.4 (1.0–1.8) (0.05) 1.3 (1.0–1.7) (0.07) 1.4 (1.1–1.8) (0.002) Co-morbidities: overall p value .02 .1 .6 .03 No 126 (57%) 57% (47–67%) 21% (14–29) 31% (22–39) 48% (39–58%) Mild/moderate 62 (28%) 53% (40–66%) 26% (14–37) 26% (15–38) 48% (35–61%) Severe 34 (15%) 33% (16–49%) 40% (23–57) 37% (20–54) 23% (8–37%) WHO at HSCTb: overall p value .002 .5 <.001 <.001 RA/RARS/del5q/RCMD(RS) 57 (26%) 73% (60–85%) 21% (10–32) 7% (0–14%) 72% (60–84%) RAEB-1/RAEB-2 124 (56%) 49% (39–58%) 28% (20–37) 34% (25–43) 38% (28–47%) AML-MDS 16 (7%) 15% (0–34%) 25% (4–46) 69% (46–91) 6% (0–18%) CMML 24 (11%) 49% (27–72%) 17% (2–33) 42% (22–61) 41% (21–61%) Cytogenetic subgroups: .8 .5 1 .8 overall p value very good/good 120 (58%) 51 (41–61%) 30% (21–38%) 30% (21–38%) 40% (31–50%) intermediate 40 (19%) 60% (43–76%) 20% (8–32%) 34% (18–50%) 46% (29–32%) Poor/very poorc 48 (23%) 49% (33–65%) 21% (8–33%) 28% (15–42%) 51% (36–66%) Missing 14 Donor type: overall p value .7 .6 .9 .6 Sibling 74 (33%) 52% (39–65%) 25% (14–35%) 28% (18–39%) 47% (35–60%) Unrelated 148 (67%) 52% (43–60%) 26% (19–33%) 32% (24–40%) 42% (34–50%) Sex match: overall p value .2 .7 .2 .2 other combinations 176 (79%) 55% (47–63%) 24% (18–31%) 30% (22–37%) 46% (38–54%) recipient-donor: m-f 46 (21%) 41% (25–57%) 28% (15–43%) 36% (22–50%) 36% (21–50%) Conditioning intensity 0.1 0.6 0.2 0.3 Standard /Myelo-ablative 99 (45%) 55% (44–67%) 25% (15–34%) 25% (17–34%) 50% (40–61%) Reduced intensity 123 (55%) 49% (39–58%) 27% (19–35%) 35% (26–44%) 38% (29–48%) RBCTd (mediana): overall p value 12 (5–29) .6 .4 .9 .5 0–20 units 155 (70%) 52% (44–61%) 24% (17–31%) 32% (24–40%) 44% (36–52%) >20 units 49 (22%) 51% (36–66%) 28% (15–41%) 29% (16–42%) 43% (29–57%) Yes, but number not known 17 (8%) 46% (16–75%) 41% (12–70%) 21% (0–44%) 38% (8–67%) Missing 1 Ferritine ng/ml (mediana): 700 (261–1554) .09 .3 .3 .1 overall p value <1000 ng/ml 115 (58%) 57% (48–67%) 22% (14–30%) 27% (19–35%) 51% (42–61%) >1000 ng/ml 81 (41%) 46% (35–58%) 28% (18–39%) 36% (25–47%) 36% (25–47%) Missing 26 C-reactive protein (mediana): 4.0 (2.2–10.1) .02 .1 .6 .4 overall p value Not elevated 146 (75%) 55% (47–64%) 22% (15–29%) 33% (25–41%) 45% (36–54%) Elevated 49 (25%) 42% (27–56%) 33% (19–46%) 28% (15–42%) 39% (24–53%) Missing 27 Chelation (yes): overall p value .6 .9 .9 .9 Yes 31 (31%) 44% (21–67%) 33% (13–53%) 34% (15–53%) 33% (13–54%) No 70 (69%) 45% (33–57%) 29% (18–40%) 33% (22–44%) 38% (26–50%) Missing 152 OS: Estimates of overall survival; NRM: non-relapse mortality; RI: relapse incidence and RFS: relapse-free survival at 3 years after HSCT, expressed as per- centage with 95% confidence intervals. Differences between outcomes until 3 years after HSCT for subgroups were evaluated by the log-rank test (OS and RFS) and the Gray test (RI and NRM); amedian (1st–3rd Qu); bmissing 1 patient; conly 9 patients had very poor cytogenetic characteristics; dnumber of red blood cell transfusions (RBCT) prior to HSCT; ejust prior to conditioning HSCT. Therefore, poor and very poor risk groups are lumped together. The median age was 59 years (range 19–76 years). intensity (RIC) regime. After conditioning, 70 patients WHO-classification at time of transplantation resulted received stem cells from a sibling, 4 from a mis- in 20 patients with RA/RARS, 36 with RCMD/RCMD-RS, matched relative, and 148 patients from an unrelated 1 with 5q-, 50 with RAEB-1, 74 with RAEB-2, 25 with donor. The incidence of acute GvHD grade I–II and CMML, and 16 with AML-MDS. In total, 70% of the grade III–IV at 100 days was 1% (25–37%) and 14% patients had received RBCT prior to HSCT. Median (9–18%), respectively. The incidence of limited or number of RBC units transfused before transplant- extensive chronic GvHD at 36 months was 47% ation: 12 units (range: 1–146 units); median ferritin lev- (40–54%) and 20% (15–26%), respectively. els: 700 ng/ml (range 8–9033 ng/ml). Median interval between diagnosis and HSCT was 10 months (range Univariable analysis of relevant factors on 1–128 months). Time between diagnosis and HSCT primary end points was <6 months for 56 patients and 6 months for 166 patients. A total of 99 patients received standard The median follow-up of the 222 registered patients conditioning (MAC) and 123 received a reduced after HSCT was 39 months with 95% confidence IRON TOXICITY IN MDS PATIENTS UNDERGOING UPFRONT HSCT 2407 intervals (CI) ranging from 36 to 44 months. OS, RFS, Ferritin levels (>1000 ng/ml) had a non-significant NRM, and RI at 36 months were 52% (95% CI: negative impact on NRM and OS after HSCT, but ele- 45–59%), 44% (95% CI: 37%–51%), 25% (95% CI: vated CRP levels (>10 mg/l) influenced OS signifi- 19%–32%) and 31% (95% CI: 24%–37%), respectively. cantly (p ¼ .02). Age had a significant impact on OS when analyzed as continuous variable per decade (HR: 1.4, 95%CI: 1.1–1.8; p ¼ .002), and on RFS (HR: 1.4, 1.1–1.8; Correlations of potentially confounding factors for p ¼ .002), but a borderline impact on NRM (HR: 1.4, the multivariable analyses 1.0–1.8; p ¼ .05) and on relapse incidence (HR: 1.3, Patients with more than 5% bone marrow blasts 1.0–1.7; p ¼ .07). To evaluate the impact of WHO-classi- fication on treatment outcome, patients were divided received a low number of red blood cell units (0–20 in 4 subgroups: patients with 5% marrow blasts or RBCT) before HSCT more frequently than patients with less at time of HSCT (RA, RARS, RCMD, RCMD-RS, 5q-), less than 5% bone marrow blasts (p ¼ .01), mainly patients with 6–19% marrow blasts (RAEB1 and explained by a shorter duration of the interval between RAEB2), patients with 20–29% marrow blasts (AML- diagnosis and HSCT in patients with more advanced MDS) and patients with CMML. The WHO classification MDS according to WHO-classification (data not shown). influenced significantly OS at 3 years (p ¼ .002) (Table The number of RBCT before HSCT was not associated 1, Figure 1). Cytogenetics according to IPSS-R catego- with the cytogenetic risk category according to IPSS-R ries had no significant impact on treatment outcome. (p ¼ .7) nor with the interval between diagnosis and However, the group with very poor-risk cytogenetics actual HSCT of the whole cohort, including patients could not be analyzed separately due to its small size with less than 5% marrow blasts (<6 vs. >6 months) (n ¼ 9) (Table 1). Only 11 patients were transplanted (p ¼ .2). As expected, ferritin levels (>1000 ng/ml vs. with bone marrow as stem cell source, precluding an <1000 ng/ml) were influenced by a number of adminis- analysis of the impact of stem cell source. Transfusion tered RBCT prior to HSCT (p < .001). Ferritin levels, burden (20 RBCT vs. >20 RBCT) did not have a sig- measured as units of 1000 mg/L were associated with nificant impact on any of the outcome parameters. elevated CRP levels (p ¼ .03) in this study. Co- Figure 1. Overall survival according to WHO Categories. Kaplan–Meier plot for OS in the whole cohort, grouped by WHO catego- ries. The corresponding 95% confidence intervals are indicated by the gray regions. The Log-rank p value is indicated. 2408 E. M. P. CREMERS ET AL. Table 2. Multivariate Cox models for assessment of the impact of relevant factors for all major outcomes. OS HR (95% CI) (p) NRM HR (95% CI) (p) RI HR (95% CI) (p) RFS HR (95% CI) (p) Basic model Age (decades) 1.4 (1.1–1.7) (.01) 1.4 (1.0–2.0) (.04) 1.1 (0.8–1.4) (.73) 1.2 (1.0–1.5) (.09) WHO classification <5% marrow blastsa 1 1 1 1 RAEB/CMML 1.8 (1.0–3.2) (.05) 1.3 (0.7–2.6) (.4) 5.5 (2.0–15.3) (<.001) 2.4 (1.4–4.2) (<.001) Transformed AML 3.0 (1.4–6.6) (<.001) 1.4 (0.5–4.6) (.5) 14.3 (4.4–47) (<.001) 4.6 (2.2–9.6) (<.001) Patient-donor sex Other combinations 1 1 1 1 Female donor into male recipient 1.2 (0.8–2.0) (.4) 1.3 (0.7–2.5) (.5) 1.2 (0.7–2.2) (.5) 1.3 (0.8–1.9) (.3) Conditioning Myeloablative 1 1 1 1 Reduced intensity 1.2 (0.8–1.9) (.3) 1.1 (0.6–2.0) (.7) 1.4 (0.8–2.3) (.2) 1.3 (0.9–1.8) (.3) Added to basic model Transfusions RBCT 20 units 1 1 1 1 RBCT >20 units 1.5 (0.9–2.5) (.09) 1.7 (0.9–3.4) (.1) 1.8 (0.95–3.3) (.07) 1.7 (1.1–2.7) (.02) C-reactive protein CRP 10 1 1 1 1 CRP >10 1.6 (1.0–2.5) (.06) 1.5 (0.8–2.8) (.2) 0.8 (0.4–1.5) (.5) 1.1 (0.7–1.7) (.8) Ferritin (units of 1000 ng/ml) 1.2 (1.0–1.4) (.05) 1.1 (0.8, 1.4) (.6) 1.3 (1.01–1.6) (.04) 1.2 (0.98–1.4) (.08) Comorbidities No 1 1 1 1 Mild/Moderate 0.9 (0.6–1.6) (.8) 1.1 (0.6–2.2) (.8) 0.7 (0.4–1.3) (.3) 0.9 (0.5–1.3) (.5) Severe 1.8 (1.03–3.0) (.04) 2.0 (0.97–4.0) (.06) 1.4 (0.7–2.7) (.4) 1.6 (0.98–2.6) (.06) OS: Estimates of overall survival; NRM: non-relapse mortality; RI: relapse incidence; RFS: relapse-free survival at 3 years after HSCT, expressed as percent- age with 95% confidence intervals; HSCT: allogeneic hematopoietic stem cell transplantation; RBCT: red blood cell transfusion; CRP: C-reactive protein. a Including RA/RARS/del5q/RCMD(RS); Patients with missing data for a variable were excluded from the models where this variable was analyzed. morbidities and intensity conditioning (MAC vs. RIC) chelation prior to HSCT was 4 months (range: were significantly associated (p < .001). 0–40 months). The median ferritin levels at HSCT was 1598 ng/ml, 9 chelated patients had ferritin levels Multivariable cox models <1000 ng/ml at the time of HSCT. Sixteen chelated patients had received >20 units of RBCT prior to The basic model was restricted to the traditional varia- HSCT. The outcome of the patients chelated prior to bles indicating a potential prognostic impact, according transplant conditioning was compared with a non- to the literature and the results from the univariable chelated control group of 70 patients who had fer- analyses (Table 2). Therefore, only WHO-classification, ritin levels >1000 ng/ml at HSCT or who had age at HSCT, donor type, sex-match, and intensity of received >20 units of RBCT prior to HCT condition- conditioning regimen were included in the model. We ing. The overall 3-year survival in the chelated group added one by one the other variables of specific inter- was 44% (21–67%) similar to the survival in the con- est in the current study: RBC transfusions, CRP levels, trol group, 45% (33–57%, p ¼ .6; Figure 2(A)). The ferritin levels (continuous in units of 1000 ng/ml) and RFS, RI, and NRM were also similar in both groups: comorbidities. This approach was necessary due to the 33% (13–54%) in the chelated patients vs. 38% highly correlated nature of these variables. The transfu- (26–50%) in the non-chelated patients, 34% sion burden prior to HSCT influenced RFS significantly (15–53%) vs. 33% (22–44%), and 32% (13–53%) vs. (HR: 1.7; p ¼ .02). The impact of pre-HSCT ferritin levels 29% (18–40%), respectively (Figure 2(B)). was minor but significant on OS (HR: 1.2; p ¼ .05) and RI (HR: 1.3; p ¼ .04). Presence of severe comorbidities Impact of phlebotomies or iron chelation after influenced OS after HSCT (HR: 1.8; p ¼ .04). Elevated HSCT on outcome CRP-levels (>10 mg/L) had a borderline negative impact on survival (HR: 1.6; p ¼ .06). Twenty patients have been treated with phlebotomies after HSCT. Most patients (80%) started phlebotomies during the first year after HSCT. The median ferritin Impact of iron chelation before HSCT on outcome levels before starting phlebotomies were: 3134 ng/ml Thirty-one (14%) patients received iron chelation (range: 937–9985 ng/ml). The number of phlebotomies prior to HSCT and ferritin levels at HSCT were avail- was available in 16 patients: 9 patients underwent able in 28 patients of them. The median duration of <10 phlebotomies and 7 patients 10 or more IRON TOXICITY IN MDS PATIENTS UNDERGOING UPFRONT HSCT 2409 Figure 2. Overall survival (A) and relapse-free survival (RFS) according to iron reduction therapy prior to Transplantation (B). Kaplan–Meier plot for OS (A) and RFS (B) in patients who either received chelation therapy or could have received chelation ther- apy based on their increased ferritin levels or received transfusions, prior to transplant. The corresponding 95% confidence inter- vals are indicated by the gray regions. Table 3. Outcome of patients with iron reduction treatment after HSCT. Landmark after HSCT (months) Start iron reduction Iron reduction treatment after HSCT after HSCT 0–6 6–12 12–24 Nr of patientsa No 101 77 51 Yes 12 27 21 OSb No 65% (54–75%) 0.08 75% (65–86%) 0.3 85% (79–98%) 0.9 Yes 90% (71–100%) 81% (61–100%) 88% (73–100%) RFSb No 56 (46–67%) 0.04 67% (55–79%) 0.3 81% (69–93%) 0.5 Yes 90% (71–100%) 57% (58–98%) 88% (74–100%) RIb No 26 %(17–35%) 0.19 18% (8–27%) 0.8 7% (0–16%) 0.6 Yes 10% (0–29%) 22% (2–42%) 12% (0–26%) NRMb No 18% (10–26%) 0.13 15% (6–24%) 0.08 12% (2–21%) 0.14 Yes 0% (0–0%) 0% (0–0%) 0% (0–0%) OS: estimates of overall survival; RFS: relapse-free survival at 3 years; RI: relapse incidence; NRM: non-relapse mortality; and after HSCT, expressed as percentage with 95% confidence intervals; HSCT: allogeneic hematopoietic stem cell transplantation. a Control group: patients with ferritin levels above 1000 ng/ml at the start of comparison. b Estimates of outcomes at 3 years after HSCT (95% confidence intervals) with p values of log-rank test/Gray test of non-treated vs. treated groups. The outcomes are measured from the three landmark points (6, 12, and 24 months after HSCT). phlebotomies. The ferritin levels decreased to levels patients. In the remaining patients, the effect was not <1000 ng/ml in 10 out of 19 patients at the time of evaluable due to missing ferritin levels (5 patients) or completion of phlebotomies or at 24 months after too short duration of chelation (7 patients). The median HSCT and decreased more than 50% in five additional duration of iron chelation in the 5 responding patients patients. In the remaining 5 patients, the effect was was 4 months (range: 1.5–7 months). not evaluable mainly due to insufficient follow-up We combined the data of both interventions, after starting phlebotomies. because the number of patients who were treated Sixteen patients have received iron chelation (defera- with either chelation or phlebotomies was relatively sirox only) after HSCT. Nine patients started chelators small, and both interventions are aiming at reducing during the first 6 months after HSCT and 13 patients the iron overload. Fourteen patients started treatment during the first year after HSCT. The median interval with either phlebotomies or chelation during the first between HSCT and starting chelation was 5 months 6 months after HSCT, and 27 patients started these (range: 1–18). The median ferritin level before starting interventions within the first 12 months after HSCT. chelation was: 3122 ng/ml (range: 69–9040 ng/ml). The The outcome of the patients treated with iron reduc- median duration of iron chelation was 4 months (range: tive interventions was compared with the untreated 0.5–40 months). The ferritin levels decreased to levels control groups with ferritin levels >1000 ng/ml alive <1000 ng/ml in 3 out of 16 patients during iron chela- and relapse-free at the landmarks of 6, 12 and tion and decreased more than 50% in four additional 24 months, respectively (Tables 3 and 4). Only patients 2410 E. M. P. CREMERS ET AL. who received iron reductive therapy within 6 months Discussion after HSCT had a significantly improved 3-year RFS Allogeneic hematopoietic stem cell transplantation compared to the non-treated patient population (90% (HSCT) is considered the most potent curative (71–100%) vs. 56% (46–67%); p ¼ .04 Figure 3, Tables 3 option in myelodysplastic syndromes (MDS). Many and 4). The survival at this landmark analysis was retrospective analyses evaluated relevant prognostic reduced compared to the control group with a 3-year parameters, to enable adequate patient selection for OS of 90% (71–100%) vs. 65% (54–75%) in the control treatment [16,17] and reviewed in [18]. This large pro- group (Tables 3 and 4). The outcomes at later land- spective observational study collected detailed infor- mark analyses did not indicate relevant differences mation on several relevant prognostic factors, with the exception of a moderate difference of the including relevant patient characteristics, disease NRM at both landmarks (Tables 3 and 4). modalities, transfusion data, and iron parameters in Table 4. Landmark population: alive and relapse free. 0–6 m 0–12 m 0–24 m Start iron reduction treatment No Yes No Yes No Yes N(%) N(%) N (%) N (%) N(%) N% Total N 101 12 77 22 51 21 WHO RA/RARS/RCMD-RS/5q- 31 (31) 3 (25) 24 (31) 5 (23) 18 (35) 6 (29) RAEB/CMML 64 (63) 8 (67) 48 (62) 16 (73) 31 (61) 14 (67) RAEB-t/sAL 6 (6) 1 (8) 5 (6) 1 (5) 2 (4) 1 (5) Transfusions Yes, nr missing 7 (7) 0 (0) 4 (5) 1 (5) 4 (8) 0 (0) Nr < ¼20 70 (69) 8 (67) 54 (70) 16 (73) 34 (67) 16 (76) Nr >20 24 (24) 4 (33) 19 (25) 5 (23) 13 (25) 5 (24) Comorbidities No comorbidity 52 (51) 6 (50) 42 (55) 12 (55) 26 (51) 10 (48) Mild/moderate 31 (31) 5 (42) 24 (31) 6 (27) 17 (33) 8 (38) Severe 18 (18) 1 (8) 11 (14) 4 (18) 8 (16) 3 (14) cGvHD before landmark No 54 (54) 7 (58) 25 (33) 6 (27) 11 (22) 3 (14) Limited 34 (34) 4 (33) 39 (51) 10 (45) 30 (60) 12 (57) Extensive 12 (12) 1 (8) 12 (16) 6 (27) 9 (18) 6 (29) Missing 1 1 1 cGvHD: chronic graft versus host disease. Table describing relevant characteristics of both groups at 6, 12 and 24 months. cGvHD: chronic graft versus host disease. Figure 3. Overall survival and relapse-free survival of patients alive and relapse-free at 6 months after transplantation, stratified in 2 groups according to iron reduction therapy given during the first 6 months after transplantation or not. Landmarked Kaplan–Meier plot for OS and RFS in patients who either received iron reduction therapy or could have received iron reduction therapy based on their increased ferritin levels or received transfusions. Patients were selected based on ferritin levels >1000 ng/ ml. The landmark time-point is indicated by the vertical dashed line. Only patients alive and relapse-free at 6 months are included. The corresponding 95% confidence intervals are indicated by the gray regions. IRON TOXICITY IN MDS PATIENTS UNDERGOING UPFRONT HSCT 2411 patients with MDS undergoing HSCT. The overall out- predicted OS [27]. Therefore, it has been postulated come of this study, and especially the NRM of 25% that transferrin saturation, NTBI, and LPI are better (95% CI: 19%–32%) at 36 months, compares favorably parameters to monitor and to study iron toxicity dur- with other recently published studies [4,6,10] despite ing conditioning for HSCT and the first two weeks the high mean age of 59 years in this study. Age, BM after HSCT [28]. When transferrin saturation exceeds blast percentage, and comorbidity at time of HSCT 85%, species of non-transferrin-bound iron (NTBI), had a significant influence on outcome after HSCT. and its redox active component labile plasma iron The overall outcome of this study, and especially the (LPI), become detectable in the plasma [29,30]. NRM at 36 months, compares favorably with other Transferrin becomes saturated immediately during recently published studies reflecting the data of this transplant conditioning and remains elevated until study showed that intensity of conditioning regimen engraftment [30]. These redox active components had no impact on overall survival, confirming several lead in various steps to associated tissue damage, other retrospective studies [5,6,19,20]. mostly cardiac, endocrine and liver tissue, and may The primary objective of this study was to study also affect clonal evolution in MDS [31]. Reduction of the impact of iron overload and iron toxicity on out- iron stores, may alleviate long-term effects of iron come after HSCT. As expected [21], the data showed toxicity in transfusion-dependent patients with MDS a significant association between transfusion burden [32]. Consensus statements advice to administer iron and ferritin levels (p < .001). A high RBCT burden, chelation therapy in those patients with an expected higher than 20 units prior to transplantation, was long-term survival [33,34]. In high-risk MDS, patients significantly associated with a decreased relapse-free may not live long enough after HSCT to be exposed survival (HR: 1.7; p ¼ .02). Although it is difficult to to the prolonged toxic effects of transfusional ther- separate the impact of transfusion load as an inde- apy. Studies the impact of iron chelation in a trans- pendent prognostic marker from the progression of plant setting is ongoing [35]. bone marrow failure and increased tumor burden in In the current study, we were able to investigate nontransplanted MDS patients, several studies the impact of iron reduction therapy on outcome after showed a significant impact of transfusion burden HSCT. It is important to realize that both high ferritin on outcome after HSCT [17,22,23], including our own levels and high transfusion burden were associated retrospective study [24]. In this study, the impact of with an inferior outcome in this study. Both the che- high transfusion burden on overall survival was less lated and its control group were selected based on explicit (HR: 1.5; p ¼ .09), in contrast to the signifi- these two poor prognostic factors. Iron overload in cantly reduced RFS, which can be explained by the the transplant setting may be reduced both by iron smoldering nature of less advanced MDS patients in chelation therapy [36,37] and by phlebotomies [38]. this cohort (only 16 patients had AML-MDS at time Administration of iron chelation therapy prior to HSCT of transplantation). This selection may be associated had no influence on treatment outcome in this study. with a prolonged survival after relapse. However, the ferritin levels of the chelated patients at Ferritin is an acute-phase protein, and therefore HSCT were still elevated with a median level of also elevated in case of infection, inflammation or 1772 ng/ml, and only 8 out the 28 chelated patients high tumor burden [25]. To correct for this con- with available ferritin levels had ferritin levels founding factor we analyzed CRP levels, another <1000 ng/ml at HSCT. This indicates that the duration acute phase protein, which was significantly corre- of iron chelation was insufficient in the majority of lated with ferritin levels. Both ferritin levels and ele- cases, probably reflecting the short period of iron che- vated CRP levels had an impact on overall survival, lation prior to HSCT in this study. More efficient iron but only ferritin levels had a significant impact on chelation prior to HSCT may be achieved by earlier relapse incidence reflecting its association with more iron reduction prior to the transplant procedure and/ advanced MDS stages. Therefore, the impact of ele- or by more vigorous iron chelation using higher dos- vated CRP levels on NRM was more pronounced ages of chelators in the immediate pre-transplant set- compared to the impact of elevated ferritin levels, ting [33,35]. confirming data from a large HSCT study in AML and Patients with MDS may also receive iron reduction MDS [26]. Ferritin levels are sometimes used as a interventions to reduce iron overload after HSCT [39]. marker of transfusion burden [27], but in the multi- We were able to evaluate the influence of iron reduc- variable analysis of that study, only co-morbidities tion therapy after HSCT in a subgroup of 35 patients, and percentage of marrow blasts at time of HSCT consisting of iron chelation in 16 patients and/or 2412 E. M. P. CREMERS ET AL. phlebotomies in 20 patients (one patient received bot Funding phlebotomies and iron chelation). Iron reduction by This study received an educational grant from Novartis. phlebotomies started within one year after HSCT in 80% and by iron chelation in 81% of the patients receiving the respective therapies. The efficacy of ORCID reducing ferritin levels by phlebotomies was excellent Eline M.P. 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