RBC Transfusion-dependent Patients Research Articles

The Effect of Oral Iron Chelator Deferiprone on Iron Overload and Oxidative Stress in Patients with Myelodysplastic Syndromes: A Study by the Israeli MDS Working Group

Background: Most patients with lower risk myelodysplastic neoplasms or syndromes (MDSs) become RBC transfusion-dependent, resulting in iron overload, which is associated with an increased oxidative stress state. Iron-chelation therapy is applied to attenuate the toxic effects of this state. Deferiprone (DFP) is an oral iron chelator, which is not commonly used in this patient population, due to safety concerns, mainly agranulocytosis. The purpose of this study was to assess the effect of DFP, on oxidative stress parameters in iron-overloaded RBC transfusion-dependent patients with lower risk MDSs. Methods: Adult lower risk MDS patients with a cumulative transfusion burden of >20 red blood cell units and evidence of iron overload (serum ferritin >1,000 ng/mL) were included in this study. DFP was administered (100 mg/kg/day) for 4 months. Blood samples for oxidative stress parameters and iron overload parameters were done at baseline and monthly: reactive oxygen species (ROS), phosphatidylserine, reduced glutathione, membrane lipid peroxidation, serum ferritin, and cellular labile iron pool. The primary efficacy variable was ROS. Tolerability and side effects were recorded as well. A paired t test was applied for statistical analyses. Results: Eighteen patients were treated with DFP. ROS significantly decreased in all cell lineages: median decrease of 58.6% in RBC, 33.3% in PMN, and 39.8% in platelets (p p p Conclusions: Herein, we showed preliminary evidence that DFP decreases iron-induced oxidative stress in MDS patients with a good tolerability profile (albeit a short follow-up period). No cases of severe neutropenia or agranulocytosis were reported. The future challenge is to prove that reduction in iron toxicity will eventually be translated into a clinically meaningful improvement.

Tolerability and efficacy of the first-in-class anti-CD47 antibody magrolimab combined with azacitidine in MDS and AML patients: Phase Ib results.

7507 Background: Magrolimab (Hu5F9-G4) is an antibody blocking CD47, a macrophage immune checkpoint and don’t eat me signal on cancers. It induces tumor phagocytosis and eliminates leukemia stem cells. Azacitidine (AZA) synergizes with magrolimab by inducing eat me signals on leukemic cells, enhancing phagocytosis. We report Ph1b data including a potential MDS registration cohort. Methods: Magrolimab+AZA was given to untreated intermediate to very high risk IPSS-R MDS and intensive chemo unfit AML patients. A magrolimab priming/intrapatient dose escalation regimen (1-30 mg/kg QW, Q2W Cycle 3+) was used. AZA was dosed 75mg/m2 days 1-7. Efficacy was assessed by IWG 2006 (MDS) and ELN 2017 (AML) criteria. Results: 68 patients (39 MDS, 29 AML) with a median age of 72 were treated with magrolimab+AZA. 19% were intermediate cytogenetic risk with 68% poor risk (13% unknown). 27% were TP53 mutant. The combo was well-tolerated with safety similar to AZA alone. Common treatment-related AEs were anemia (38%), fatigue (21%), neutropenia (19%), thrombocytopenia (18%) and infusion reaction (16%). Treatment-related febrile neutropenia was 1.5%. Only 1 patient (1.5%) discontinued due to an AE. In RBC transfusion dependent patients, 58% of MDS and 64% of AML patients became transfusion independent. 30/33 (91%) efficacy evaluable MDS patients had an objective response (42% CR, 24% marrow CR (4/8 also with HI), 3% PR, 21% HI alone, 9% SD). MDS patient responses deepened on study, with a 56% CR rate in patients with ≥ 6 mo follow-up. In AML, 16/25 (64%) responded (40% CR, 16% CRi, 4% PR, 4% MFLS, 32% SD, 4% PD). In 12 TP53 mutant AML patients, 75% had a CR+CRi (42% CR, 33% CRi, 17% SD, 8% PD). Cytogenetic CR was seen in 35% and 50% of responding MDS and AML patients. 22% of MDS and 50% of AML patients with CR/CRi/marrow CR were MRD negative by flow cytometry. Median duration of response is not reached in either MDS or AML, including TP53 mutant AML, with a median follow-up of 5.8, 8.8 and 9.4 mos, respectively (range: 1.9 – 16.8 mos). 91% of MDS and 100% of AML responding patients are in response at 6 mos. The 6 mo overall survival estimate is 100% in MDS and 91% in TP53 mutant AML patients. Conclusions: Magrolimab is a macrophage targeting immunotherapy that with AZA is well tolerated with durable efficacy in MDS, AML, particularly TP53 mutant, a poor prognostic group. A potential registration single arm MDS cohort is ongoing (NCT03248479). ENHANCE, a randomized Ph3 MDS trial is planned. Additional patients/analyses will be reported. Funded by Forty Seven and CIRM. Clinical trial information: NCT03248479 .

Impact Of The Proportion Of Metaphases With Isolated Del(5q) On Clinical Outcomes In Lenalidomide (LEN)-Treated Patients With IPSS Low-/Int-1-Risk Myelodysplastic Syndromes (MDS) In MDS-003 and MDS-004

IntroductionThe proportion of aberrant metaphases is prognostic for overall survival (OS) in MDS patients with trisomy 8 (Mallo M, et al. Leuk Res. 2011;35:834-6). The impact of the proportion of metaphases with del(5q) on clinical outcomes, including OS, disease progression and response to therapy with LEN in MDS remains undefined. In two large multicenter studies of LEN (MDS-003 and MDS-004) in RBC transfusion-dependent patients with International Prognostic Scoring System (IPSS) Low- or Intermediate (Int)-1-risk del(5q) MDS, RBC transfusion independence (TI) ≥ 8 weeks was achieved in 51–67% of patients (List A, et al. N Engl J Med. 2006;355:1456-65; Fenaux P, et al. Blood. 2011;118:3765-76). This retrospective analysis evaluated response to treatment, progression to acute myeloid leukemia (AML) and OS by proportion of del(5q) metaphases in patients with isolated del(5q) from the MDS-003 and 004 studies. MethodsIn order to allow sufficient patient numbers for analysis, ≥ 16 metaphases were evaluated for del(5q) by standard karyotyping (MDS-003 and MDS-004) and 200 interphase nuclei were evaluated by fluorescence in situ hybridization (FISH; MDS-004 only) using a probe for the commonly deleted region 5q31 (LSI EGR1/D5S721, Abbott, Wiesbaden, Germany). Patients received LEN on days 1–21 of each 28-day cycle (10 mg) or continuously (5 mg or 10 mg), or placebo. In MDS-004, patients randomized to placebo could cross over to LEN 5 mg by week 16. RBC-TI ≥ 26 weeks, time to AML progression and OS were analyzed by the proportion of del(5q) metaphases or interphases (≤ 60% vs > 60%) using standard karyotyping and FISH, respectively. ResultsOf the 353 patients from MDS-003 and MDS-004, 194 had isolated del(5q) by standard karyotyping; median proportion of del(5q) metaphases was 96% (range 4–100). Baseline characteristics including age, time from diagnosis, RBC transfusion burden, hemoglobin level, platelet and absolute neutrophil counts were comparable among patients with ≤ 60% (n = 21) and > 60% (n = 173) del(5q) metaphases. Rates of RBC-TI ≥ 26 weeks were similar across patients in the ≤ 60% and > 60% groups (P = 0.6515). Time to AML progression was comparable for patients in the ≤ 60% group versus the > 60% group (log-rank test P = 0.9802); 2-year rates were 22.2% (95% confidence interval [CI]: 7.7–54.5%) and 14.6% (95% CI: 9.9–21.2%), respectively. Time to AML progression was similar when analyzed with death without AML as competing risk (Gray's test P = 0.5514). OS was longer in the > 60% versus the ≤ 60% group (log-rank test P = 0.0436); median OS was 3.7 years (95% CI: 3.0–4.2) and 2.4 years (95% CI: 1.5–4.9), respectively. In MDS-004, the proportion of del(5q) interphases was analyzed using FISH in 106 patients, including 46 with ≤ 60% and 60 with > 60%. When analyzed by FISH, rates of RBC-TI ≥ 26 weeks were similar across patients in the ≤ 60% and > 60% groups (P = 1.000). Time to AML progression and OS were similar across these groups (log-rank test P = 0.7311 and P = 0.8639, respectively) when analyzed by FISH. In the ≤ 60% and > 60% groups respectively, 2-year AML progression rates were 14.8% (95% CI: 6.9–30.1%) and 18.6% (95% CI: 10.4–32.0%), and median OS was 3.1 years (95% CI: 2.3–4.8) and 2.9 years (95% CI: 2.3–4.4). Time to AML progression was similar when analyzed with death without AML as competing risk (Gray's test P = 0.8631). ConclusionsIn IPSS Low- or Int-1-risk MDS patients with isolated del(5q) treated with LEN in MDS-003 and MDS-004 studies, baseline characteristics, RBC-TI ≥ 26 weeks and AML progression were comparable in patients with > 60% versus ≤ 60% del(5q) metaphases. Although similar across groups when analyzed by FISH in a subset of patients, surprisingly, OS was longer in patients with > 60% del(5q) metaphases than in those with ≤ 60% del(5q) metaphases by standard karyotyping. However, the number of patients with ≤ 60% del(5q) metaphases was limited and no adjustment was made for multiple testing. These findings suggest that the number of cells with the isolated del(5q) abnormality measured by FISH does not impact clinical outcome in this RBC transfusion-dependent study population, but this finding could not be confirmed for OS by standard karyotyping. Disclosures:Giagounidis:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. List:Celgene: Serve on Celgene Data Safety & Monitoring Committee Other. Hellström-Lindberg:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Mufti:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Schlegelberger:Celgene: Consultancy. Morrill:Celgene: Employment, Equity Ownership. Wu:Celgene: Employment, Equity Ownership. Skikne:Celgene: Employment, Equity Ownership. Fenaux:Celgene: Honoraria.

Health-related quality of life outcomes of lenalidomide in transfusion-dependent patients with Low- or Intermediate-1-risk myelodysplastic syndromes with a chromosome 5q deletion: Results from a randomized clinical trial

We report health-related quality of life (HRQL) outcomes assessed using the Functional Assessment of Cancer Therapy-Anemia (FACT-An) among 167 RBC transfusion-dependent patients with IPSS Low-/Intermediate-1-risk del5q31 MDS treated with lenalidomide versus placebo in a randomized phase 3 clinical trial, MDS-004. Mean baseline to 12 week changes in FACT-An Total scores improved following treatment with lenalidomide 5 and 10mg (+5.7 and +5.7, respectively) versus placebo (−2.8) (both p<0.05). Clinically important changes in HRQL from baseline were observed at weeks 12, 24, 36, and 48 among RBC-TI≥26 week responders in both treatment groups. Lenalidomide treatment may be effective in improving HRQL outcomes.

Deferasirox Reduces Serum Ferritin and Labile Plasma Iron in RBC Transfusion–Dependent Patients With Myelodysplastic Syndrome

This 3-year, prospective, multicenter trial assessed the safety and efficacy of deferasirox in low- or intermediate-1-risk myelodysplastic syndrome (MDS). Eligible patients had serum ferritin ≥ 1,000 μg/L and had received ≥ 20 units of RBCs with ongoing transfusion requirements. The starting dose of deferasirox was 20 mg/kg/d, with dose escalation up to 40 mg/kg/d permitted. A total of 176 patients were enrolled, and 173 patients received therapy. Median serum ferritin decreased 23% in the 53% of patients who completed 12 months of treatment (n = 91), 36.7% in patients who completed 2 years (n = 49), and 36.5% in patients who completed 3 years (n = 33) despite continued transfusion requirement. Reduction in serum ferritin significantly correlated with ALT improvement (P < .001). Labile plasma iron (LPI) was measured quarterly during the first year of the study. Sixty-eight patients (39.3%) had elevated LPI at baseline. By week 13, LPI levels normalized in all patients with abnormal baseline level. Fifty-one (28%) of 173 patients experienced hematologic improvement by International Working Group 2006 criteria; of these, only seven patients received growth factors or MDS therapy. Over the 3-year study, 138 (79.8%) of 173 patients discontinued therapy, 43 patients (24.8%) because of adverse events or disease progression and 23 patients (13.2%) because of abnormal laboratory values. The most common drug-related adverse events were gastrointestinal disturbances and increased serum creatinine. There were 28 deaths, none of which were considered related to deferasirox. Deferasirox reduces serum ferritin and LPI in transfusion-dependent patients with MDS. A subset of patients had an improvement in hematologic and hepatic parameters.

Analysis of Second Primary Malignancies in Lenalidomide-Treated Patients with IPSS Low- or Int-1-Risk Myelodysplastic Syndromes

Abstract 1704 Background:Lenalidomide (LEN) is approved in the US for the treatment of RBC transfusion-dependent patients with IPSS Low- or Int-1-risk myelodysplastic syndromes (MDS) with del(5q), with or without other cytogenetic abnormalities. In a phase 3 trial, treatment with LEN 5 mg and 10 mg resulted in RBC transfusion independence (TI) for ≥ 26 weeks in 43% and 56% of such patients, cytogenetic response in 25% and 50%, and a significant improvement of health-related quality of life (p <.05 for both 5 mg and 10 mg). Achievement of RBC-TI ≥ 8 weeks was associated with a significantly reduced risk of AML progression and death (p <.05 for both) (Fenaux P et al. Blood 2011;doi: 10.1182/blood-2011-01-330126). In newly diagnosed multiple myeloma patients, results of phase 3 trials showed a numerical imbalance in the occurrence of second primary malignancies (SPMs) between patients treated with LEN (in combination with melphalan or immediately after high-dose melphalan therapy and stem cell transplantation) and control cohorts. SPMs were analyzed in clinical trials of LEN across indications, including MDS. Methods: This was a single arm analysis of SPM data retrieved from RBC transfusion-dependent patients with IPSS Low- or Int-1-risk MDS with or without del(5q) who received LEN as monotherapy in 5 studies (MDS-001, -002, -003, -004, and -007). The cutoff date was February 28, 2011. SPMs were defined using MedDRA (Medical Dictionary for Regulatory Activities) categories of invasive SPMs (hematologic malignancies and solid tumors) and non-melanoma skin cancers (NMSC). Acute myeloid leukemia (AML) is considered part of the natural history of disease progression in MDS. Although further follow-up is needed, results of a phase 3 study showed no obvious evidence for an increased risk of AML progression in LEN-treated RBC transfusion-dependent patients with IPSS Low- or Int-1-risk MDS and del(5q) (Fenaux P et al. Blood 2011;doi: 10.1182/blood-2011-01-330126). AML was not included in the present analysis. The overall number of SPMs (invasive malignancies and NMSC), and the number and incidence rate (IR) of all invasive SPMs were evaluated, with IR defined as the number of new events per 100 person-years (pys). The IR of invasive SPMs was compared with the IR of new events of invasive cancer as reported from the SEER (Surveillance, Epidemiology, and End Results) cancer registry (2.1/100 pys for persons aged ≥ 65 years) (Howalder N et al. National Cancer Institute, 2011). Results: The combined population of all 5 studies comprised 557 LEN-treated patients. The median age was 71 years (range 27–95 years) and 72% of patients were aged ≥ 65 years. 88 patients (15.8%) had a prior history of cancer including malignant melanoma, meningioma, breast cancer, lung cancer, squamous cell carcinoma, and basal cell carcinoma. A total of 28 patients (5.0%) developed ≥ 1 SPM, including 17 (3.1%) with an invasive SPM and 12 (2.2%) with NMSC; 1 patient had both an invasive malignancy and a NMSC. Two of the 17 patients with invasive SPMs had a B-cell malignancy and 15 had solid tumors of heterogeneous type. Of the 28 patients with SPMs in total, 5 patients had a prior history of cancer. The IR of invasive SPMs was 2.60/100 pys (95% confidence interval 1.56–4.07), which is consistent with the IR reported in the SEER database among patients in this age group (2.1/100 pys for persons aged ≥ 65 years). The median time to onset of SPMs was 13.5 months (range 0.3–48.6 months). Conclusion: There was no clear evidence to associate LEN treatment with an increased risk of developing SPMs in patients with Low- or Int-1-risk MDS with or without del(5q). The IR of invasive SPMs among these LEN-treated patients is what would be expected from population-based estimates of invasive cancer incidence among persons in this age group. The collection of data on SPMs in LEN-treated patients including post-marketing information is ongoing. Disclosures:Giagounidis:Celgene Corporation: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees. List:Celgene Corporation: Consultancy, Honoraria, Research Funding. Fenaux:Merck: Honoraria; Johnson & Johnson: Honoraria; Amgen: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Celgene Corporation: Honoraria, Research Funding; Cephalon: Honoraria; Novartis: Honoraria. Benettaib:Celgene Corporation: Employment, Equity Ownership. Brown:Celgene Corporation: Employment, Equity Ownership. Zhong:Celgene Corporation: Employment, Equity Ownership. Brandenburg:Celgene Corporation: Employment, Equity Ownership. Mufti:Celgene Corporation: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding.

Lenalidomide Treatment Is Not Related to AML Progression Risk but Is Associated with a Survival Benefit in RBC Transfusion-Dependent Patients with IPSS Low- or Int-1-Risk MDS with del5q: Results From a Comparative Study

Abstract 119 Background: Lenalidomide (LEN) treatment resulted in RBC transfusion independence for ≥ 8 wks in 51–67% of patients (pts) and cytogenetic response in 25–73% of pts with lower-risk MDS and del5q in 2 large multicenter trials (MDS-003 and -004) (List A et al. NEJM 2006;355:1456–65; Fenaux P et al. Blood 2011; doi:10.1182/blood-2011-01-330126). However, these studies were either single-arm or allowed early crossover to LEN, thus data on the influence of LEN on AML progression and overall survival (OS) is lacking. Aims: To assess the risk of AML progression and death in LEN-treated MDS-003 and -004 pts vs untreated MDS pts with del5q from a large multicenter registry, and to determine relevant risk factors. Methods: Data from 459 MDS pts with del5q entered into local or regional MDS registries were retrospectively collected from 9 centers (Europe, USA, Australia) using a uniform minimal data set. Eligible pt controls had IPSS Low-/Int-1-risk MDS and were RBC transfusion-dependent (≥ 1 unit/8 wks), reflecting the relevant inclusion criteria for both trials, and received best supportive care only including ESAs. Incidence of AML progression was assessed using a cumulative incidence estimator in the presence of competing risk (ie, death), and considering left truncation (LT) for the LEN cohort. OS was assessed using a cumulative probability estimator considering LT. Cox proportional hazards (PH) models with LT were used to assess the impact of LEN treatment and baseline factors (ie, age, sex, cytogenetics, bone marrow [BM] blast %, transfusion burden, no. of cytopenias, hemoglobin [Hgb] level [g/dL], and platelet and neutrophil counts) on risk of AML progression and death. LT is a statistical method to correct for different starting points of follow-up (ie, date of first LEN dose in clinical trial pts vs date of diagnosis in registry pts). Results: We analyzed 295 LEN-treated and 125 untreated pts. Baseline characteristics of treated (at first LEN dose) vs untreated (at diagnosis) pts were similar: mean age 65.0 vs 66.2 yrs; female sex 71% vs 68%; IPSS Low-/Int-1-risk 43%/57% vs 43%/57%. Median observation time was 4.3 vs 4.6 yrs. Baseline RBC transfusion burden was higher in the LEN cohort (median [range] units/8 wks: 6 [1–25] vs 2 [1–10]). Two- and 5-yr cumulative AML incidences were 7% and 23% for LEN vs 12% and 20% for the untreated cohort. Two- and 5-yr cumulative OS probabilities were 90% and 54% for LEN vs 74% and 41% for the untreated cohort. Median time to AML progression has not been reached for either cohort. Median OS was 5.2 yrs (95% CI 4.5–5.9) for LEN-treated vs 3.8 yrs (95% CI 2.9–4.8) for untreated pts. In the final Cox PH models, LEN treatment (hazard ratio [HR].939; p =.860) and 1 cytogenetic abnormality (abn) in addition to del5q (HR 1.111; p =.755) did not increase the risk of AML progression. Significant factors associated with an increased risk of AML progression were complex cytogenetics (del5q plus > 1 abn; HR 3.627; p =.002), BM blasts 5–10% (HR 2.215; p =.016), and higher transfusion burden (HR 1.097 [10% increase in risk per unit at baseline]; p =.029); higher Hgb levels were associated with a reduced risk (HR.857; p =.054). Regarding survival, LEN treatment was associated with a reduced risk of death (HR.597; p =.012). Other factors associated with decreased mortality were higher Hgb levels (HR.883; p =.028), higher platelet counts (HR.999; p =.035), and female sex (HR.598; p =.002). Higher transfusion burden (HR 1.056; p =.037) and age (HR 1.049; p Disclosures: Kuendgen:Celgene Corporation: Honoraria. List:Celgene Corporation: Consultancy, Honoraria, Research Funding. Fenaux:Merck: Honoraria; Johnson & Johnson: Honoraria; Amgen: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Celgene Corporation: Honoraria, Research Funding; Cephalon: Honoraria; Novartis: Honoraria. Giagounidis:Celgene Corporation: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees. Brandenburg:Celgene Corporation: Employment, Equity Ownership. Backstrom:Celgene Corporation: Employment, Equity Ownership. Glasmacher:Celgene Corporation: Employment, Equity Ownership. Hasford:Celgene Corporation: Research Funding. Germing:Celgene Corporation: Honoraria, Research Funding.

Prognostic Factors of Long-Term Outcomes In Low- or Int-1-Risk MDS with del5q Treated with Lenalidomide (LEN): Results From a Randomized Phase 3 Trial (MDS-004)

AbstractAbstract 4027▪ Background:Transfusion dependence is a significant negative predictor of overall survival (OS) and risk of AML-progression in MDS (Malcovati L, et al. JCO 2007;25:3503-10). LEN 5 mg and 10 mg induced significant RBC-transfusion independence (TI) versus placebo (PBO) in a randomized, phase 3, multicenter, double-blind (DB) study (MDS-004) in RBC transfusion-dependent patients (pts) with Low- or Int-1-risk MDS with del5q (Fenaux P, et al. Blood 2009;114:Abstract 944). The aim of this analysis is to identify prognostic factors for AML-free survival and OS during LEN treatment in the MDS-004 study after prolonged follow-up (pts enrolled between July 8, 2005 and July 26, 2007; last pt visit June 14, 2010; final data cutoff July 9, 2010). Methods:LEN-naïve pts with RBC transfusion-dependent Low- or Int-1-risk del5q MDS were randomized to receive LEN 5 mg on days 1–28 or LEN 10 mg on days 1–21, both of every 28-day cycle, or PBO. First response was assessed at 16 wks. Responders continued DB treatment for up to 52 wks, until erythroid relapse or disease progression. Pts who completed 52 wks of therapy could enter an open label (OL) extension phase at their current LEN dose. PBO and LEN 5 mg recipients who did not respond by wk 16 or who had erythroid relapse could receive LEN 5 or 10 mg, respectively, in the OL phase. This analysis included data through completion of the OL phase for pts randomized to LEN 5 and 10 mg combined in the DB phase; pts randomized to PBO were excluded as all except 11 pts crossed-over to LEN 5 mg. LEN 5 and 10 mg dose groups were comparable, allowing data for the two groups to be combined. A Cox proportional hazard model was used to evaluate effect of potential baseline risk factors, with RBC-TI ≥ 26 wks and cytogenetic response (CyR) as time-dependent covariates on AML-free survival and OS. The full model with all covariates and the final model, based on backward model selection method, are presented. Results:All 138 pts randomized to LEN who received ≥ 1 dose were included: median age 68 y (range 36–86); 74% of pts were female; 66% had an isolated del5q abnormality and 28% had ≥ 1 additional abnormality; and 43% of pts had WHO-based Prognostic Scoring System (WPSS) low/int risk, 32% high/very high, and 25% missing data. At baseline, median time since diagnosis was 2.7 y (range 0.2–29.2) and median RBC transfusion requirement was 6 units/8 wks (range 1–25). Duration of LEN was 12.9 mo (range 0.3–36.7); 54 of 62 responders entered the OL phase. Median follow-up for the cohort was 36 mo (range 0.4–59.4). Overall, 31 (22%) pts progressed to AML (median time to AML progression 4.01 y; 95% confidence interval [CI] 3.17–4.03) and 66 (48%) died (median OS 3.68 y; 95% CI 2.93–not estimable). The cumulative 3-year AML-progression rate was 34.8% and the 3-year OS rate was 56.0%. Multivariate results are presented in the Table. Achieving RBC-TI ≥ 26 wks was associated with a 45% and 51% reduction in the risk of AML progression (P=0.022) and death (P=0.008), respectively. Lower baseline ferritin level and younger age were associated with a reduced risk of AML-progression and death. Conclusion:Achievement of RBC-TI with LEN was associated with a significantly reduced risk of AML progression and death. Other predictors for longer AML-free survival and OS were lower baseline ferritin levels and younger age. Disclosures:Fenaux:Celgene: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; J&J: Honoraria; Merck: Honoraria; Cephalon: Honoraria; Novartis: Honoraria. Giagounidis:Celgene: Consultancy, Honoraria. Beyne-Rauzy:Amgen: Consultancy; Celgene: Consultancy, Research Funding; Roche: Research Funding; Novartis: Consultancy. Mufti:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Mittelman:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Muus:Celgene: Membership on an entity's Board of Directors or advisory committees; Alexion: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Sanz:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Backstrom:Celgene: Employment, Equity Ownership. Fu:Celgene: Employment, Equity Ownership. Hellström-Lindberg:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Arsenic Trioxide in Patients With Myelodysplastic Syndromes: A Phase II Multicenter Study

Evaluation of the safety and efficacy of arsenic trioxide in patients with myelodysplastic syndromes (MDS). MDS patients diagnosed according to standard French-American-British criteria received a loading dose of 0.3 mg/kg per day of arsenic trioxide for 5 days followed by a maintenance dose of 0.25 mg/kg arsenic trioxide twice weekly for 15 weeks. Patients were divided into two cohorts: lower-risk MDS (International Prognostic Scoring System risk category low or intermediate 1) and higher-risk MDS (International Prognostic Scoring System risk category intermediate 2 or high). Modified International Working Group criteria were used for response evaluation. Of 115 patients enrolled and treated in the study, 67% of patients were transfusion dependent at baseline; median age was 68 years. Most treatment-related adverse events were mild to moderate. The overall rate of hematologic improvement (intent-to-treat) was 24 (19%) of 115, including one complete and one partial response in the higher-risk cohort. The hematologic response rates were 13 (26%) of 50 and 11 (17%) of 64 in patients with lower-risk and higher-risk MDS, respectively. Major responses were observed in all three hematologic lineages; 16% of RBC transfusion-dependent patients and 29% of platelet transfusion-dependent patients became transfusion independent. At data cut off, the median response duration was 3.4 months, with responses ongoing in nine patients. Arsenic trioxide treatment consisting of an initial loading dose followed by maintenance therapy has moderate activity in MDS, inducing hematologic responses in both lower- and higher-risk patients. This activity combined with a manageable adverse effect profile warrants the additional study of arsenic trioxide, particularly in combination therapy, for the treatment of patients with MDS.