ALBERT

Description: Introduction: Few treatment options are available to RBC transfusion-dependent pts with lower-risk MDS (LR-MDS) who are refractory/ineligible for erythropoiesis-stimulating agents (ESAs). Luspatercept is a first-in-class erythroid maturation agent that binds select TGF-β superfamily ligands to reduce aberrant Smad2/3 signaling and enhance late-stage erythropoiesis. In the phase 3, randomized, double-blind, placebo-controlled MEDALIST study (NCT02631070), luspatercept significantly reduced transfusion burden vs placebo. Longer-term efficacy analyses of the MEDALIST study (data cutoff Jan 7, 2019), including multiple responses, and safety are presented here. Methods: Eligible pts were ≥ 18 years of age with IPSS-R-defined Very low-, Low-, or Intermediate-risk MDS with RS (World Health Organization 2016 criteria); were refractory, intolerant, or unlikely to respond to ESAs (serum erythropoietin 〉 200 U/L); and required regular RBC transfusions. Pts were randomized 2:1 to luspatercept (1.0 mg/kg titrated up to 1.75 mg/kg, if needed) or placebo, subcutaneously every 3 weeks (wks). This analysis assessed the achievement and number of individual response periods of RBC transfusion independence (RBC-TI) ≥ 8 wks. Clinical benefit, defined as achieving RBC-TI ≥ 8 wks and/or modified hematologic improvement-erythroid (HI-E) response per International Working Group 2006 criteria, was also assessed, along with total duration of clinical benefit (time from achieving clinical benefit to discontinuation due to loss of benefit, adverse events [AEs], or other reasons). Longer-term efficacy and safety were also evaluated. Results: Pts were assessed for RBC transfusion burden/8 wks in the 16 wks before randomization: 66 pts received 2 to 〈 4 U RBCs (30.1% and 26.3% of pts receiving luspatercept and placebo, respectively), 64 received ≥ 4 to 〈 6 U (26.8% and 30.2%, respectively), and 99 received ≥ 6 U (43.1% and 43.4%, respectively); both arms had a median baseline burden of 5 RBC U/8 wks. Compared with our previous analysis and earlier data cutoff of May 8, 2018 (Fenaux P, et al. Blood. 2018;132:1), we now report that as of Jan 7, 2019, 72 (47.1%) pts treated with luspatercept and 12 (15.8%) treated with placebo achieved RBC-TI ≥ 8 wks. Analysis of multiple response periods of RBC-TI ≥ 8 wks in the luspatercept responders (i.e. initial RBC-TI ≥ 8 wks, followed by transfusion, followed by another period of RBC-TI ≥ 8 wks) demonstrated that 48 (66.7%) pts had ≥ 2 separate response periods, 22 (30.6%) had ≥ 3, 12 (16.7%) had ≥ 4 , and 7 (9.7%) had ≥ 5. Of the 12 pts achieving RBC-TI ≥ 8 wks with placebo, 4 (33.3%) had ≥ 2 responses; none had 〉 3. Overall, 48 (31.4%) pts receiving luspatercept and none receiving placebo remained on treatment as of the Jan 7, 2019 data cutoff. Median treatment duration was 50.9 (range 5.9-147.0) wks in pts receiving luspatercept vs 24.0 (range 7.4-103.0) wks in pts receiving placebo. Median duration of the longest period of RBC-TI ≥ 8 wks during Wks 1-48 was 30.6 (95% confidence interval [CI] 20.6-50.9) wks with luspatercept and 18.6 (95% CI 10.9-not evaluable) wks with placebo. Median total duration of clinical benefit was 83.6 and 26.8 wks for pts responding to luspatercept (n = 97) and placebo (n = 20), respectively. Of the 97 luspatercept-treated pts evaluable for clinical benefit, median duration of clinical benefit in pts with baseline transfusion burden of 4 to 〈 6 U/8 wks was 87.9 (range 13-125) wks, of 〈 4 U/8 wks was 84.7 (range 21-147) wks, and of ≥ 6 U/8 wks was 64.9 (range 8-122) wks. Twelve luspatercept-treated pts did not require a transfusion after the first dose of luspatercept up to Wk 48 or until time of analysis; as of Jan 7, 2019 data cutoff, 3 (25%) of those pts maintained response. AEs occurring more frequently with luspatercept vs placebo (fatigue, diarrhea, asthenia, dizziness) occurred early (Cycles 1-4), were mainly grade 1 or 2, decreased over time, and were not associated with a higher dose level. Progression to acute myeloid leukemia was similar in pts receiving luspatercept (n = 3 [2.0%]) and those receiving placebo (n = 1 [1.3%]). Conclusions: Most LR-MDS pts achieving RBC-TI and/or HI-E with luspatercept in the MEDALIST study had multiple responses with durable clinical benefit superior to that of pts receiving placebo, including those with a high baseline transfusion burden. AEs were mainly grade 1 or 2, decreased over time, and were not correlated with a higher dose level. Disclosures Fenaux: Aprea: Research Funding; Jazz: Honoraria, Research Funding; Astex: Honoraria, Research Funding; Celgene Corporation: Honoraria, Research Funding. Mufti:Cellectis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Buckstein:Celgene: Consultancy, Honoraria, Research Funding; Takeda: Research Funding. Santini:Celgene Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Honoraria; Acceleron: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Menarini: Membership on an entity's Board of Directors or advisory committees. Díez-Campelo:Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Finelli:Celgene Corporation: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau. Ilhan:Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Alexion: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees. Komrokji:DSI: Consultancy; JAZZ: Consultancy; celgene: Consultancy; Agios: Consultancy; pfizer: Consultancy; Novartis: Speakers Bureau; JAZZ: Speakers Bureau; Incyte: Consultancy. List:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Zeidan:Trovagene: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Research Funding; Jazz: Honoraria; Ariad: Honoraria; Agios: Honoraria; Novartis: Honoraria; Astellas: Honoraria; Daiichi Sankyo: Honoraria; Cardinal Health: Honoraria; Seattle Genetics: Honoraria; BeyondSpring: Honoraria; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Acceleron Pharma: Consultancy, Honoraria, Research Funding; Celgene Corporation: Consultancy, Honoraria, Research Funding; Medimmune/AstraZeneca: Research Funding; Otsuka: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding. Verma:Stelexis: Equity Ownership, Honoraria; Acceleron: Honoraria; Celgene: Honoraria; BMS: Research Funding; Janssen: Research Funding. Laadem:Celgene Corporation: Employment, Equity Ownership. Ito:Celgene Corporation: Employment, Equity Ownership. Zhang:Celgene Corporation: Employment, Equity Ownership. Rampersad:Celgene Corp: Employment, Equity Ownership. Sinsimer:Celgene Corporation: Employment, Equity Ownership. Linde:Acceleron Pharma: Employment, Equity Ownership; Fibrogen, Inc.: Equity Ownership; Abbott Laboratories, Inc.: Equity Ownership. Garcia-Manero:Amphivena: Consultancy, Research Funding; Helsinn: Research Funding; Novartis: Research Funding; AbbVie: Research Funding; Celgene: Consultancy, Research Funding; Astex: Consultancy, Research Funding; Onconova: Research Funding; H3 Biomedicine: Research Funding; Merck: Research Funding. Platzbecker:Novartis: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. OffLabel Disclosure: Luspatercept is an investigational therapy that is not approved for any use in any country. Luspatercept is currently being evaluated for potential use in patients with anemia due to myelodysplastic syndromes, beta-thalassemia, or myelofibrosis.

Description: Introduction: Lower-risk MDS is characterized by anemia and ineffective erythropoiesis leading to RBC transfusion dependence. Effective treatment for anemia remains an unmet medical need. Patients with MDS may also experience additional cytopenias that may complicate treatment and contribute to infections and bleeding events. Here, we report hematologic improvement (HI) outcomes for patients in the MEDALIST trial (ClinicalTrials.gov identifier: NCT02631070), a phase 3, randomized, double-blind, placebo-controlled study evaluating the efficacy and safety of luspatercept, a first-in-class erythroid maturation agent that binds select TGF-β superfamily ligands to reduce aberrant Smad2/3 signaling and enhance late-stage erythropoiesis. Methods: Eligible patients in the MEDALIST trial were adults with anemia due to Very low-, Low-, or Intermediate-risk MDS with RS according to the Revised International Prognostic Scoring System; were refractory, intolerant, or ineligible to receive erythropoiesis-stimulating agents (ESAs); and required RBC transfusions. Patients received luspatercept (starting dose of 1.0 mg/kg and titration up to 1.75 mg/kg, if needed) or placebo subcutaneously every 3 weeks for ≥ 24 weeks. Platelet and neutrophil counts were assessed by the central laboratory. Secondary endpoints included HI-neutrophil (HI-N) and -platelet (HI-P) responses, using International Working Group 2006 criteria, over any consecutive 56-day period. Mean changes from baseline in platelets and neutrophils were also evaluated. Results*: A total of 94.8% patients in the luspatercept arm and 97.4% in the placebo arm had refractory cytopenia with multilineage dysplasia and RS at baseline. Mean neutrophil and platelet counts at baseline for patients in the luspatercept arm were 2.8 x 109/L and 259 x 109/L, respectively, and in the placebo arm were 2.7 x 109/L and 252 x 109/L, respectively. Neutropenia (〈 1 x 109/L) was confirmed at baseline in 15 (9.8%) and 10 (13.2%) patients in the luspatercept and placebo arms, respectively. Fifty-one (33.3%) patients in the luspatercept arm and 22 (28.9%) in the placebo arm received granulocyte colony-stimulating factor in combination with ESAs prior to randomization. A total of 8 (5.2%) and 6 (7.9%) patients receiving luspatercept and placebo, respectively, had baseline thrombocytopenia (〈 100 x 109/L); no patients received prior platelet transfusions. Fifteen (9.8%) and 10 (13.2%) patients in the luspatercept and placebo arms, respectively, were evaluable for HI-N (i.e. baseline neutrophils 〈 1 x 109/L); 3/15 (20%) of those receiving luspatercept and 1/10 (10%) of those receiving placebo achieved HI-N in Weeks 1-48. Among patients who were evaluable for HI-P (i.e. baseline platelets 〈 100 x 109/L), 5/8 (62.5%) of those receiving luspatercept and 2/6 (33%) of those receiving placebo achieved HI-P in Weeks 1-48 (Table). None of the luspatercept HI-P responders received platelet transfusions. Mean changes from baseline in neutrophils of 0.94 x 109/L with luspatercept and 0.04 x 109/L with placebo were observed at Week 15, with early increases reported for luspatercept by Day 8 (0.86 vs 0.08 x 109/L for placebo). Mean increases in neutrophils at Day 8 occurred in both luspatercept responders (by MEDALIST primary endpoint; 1.0 x 109/L) and non-responders (0.8 x 109/L). Mean changes from baseline in platelets of 29 x 109/L were observed with luspatercept and 0.9 x 109/L with placebo by Week 12, but early increases were observed with luspatercept by Day 8 (18 vs 3 x 109/L for placebo) and mean increases in platelets at Day 8 occurred in both luspatercept responders (21.4 x 109/L) and non-responders (16.5 x 109/L). No patients in either arm experienced grade 3 or 4 treatment-emergent thrombocytopenia. Treatment-related grade 3 or 4 neutropenia was reported in 1 (0.7%) patient receiving luspatercept and 1 (1.3%) patient receiving placebo. Conclusions: Although only a minority of patients were evaluable for HI-P/HI-N response based on entry criteria for the study, luspatercept treatment resulted in a mean increase from baseline in platelet and neutrophil counts in most patients overall vs placebo, regardless of response status. These improvements were observed early following treatment initiation and then stabilized. Luspatercept did not contribute to the worsening of cytopenias vs placebo. *Data cutoff: May 8, 2018. Disclosures Garcia-Manero: Amphivena: Consultancy, Research Funding; Helsinn: Research Funding; Novartis: Research Funding; AbbVie: Research Funding; Celgene: Consultancy, Research Funding; Astex: Consultancy, Research Funding; Onconova: Research Funding; H3 Biomedicine: Research Funding; Merck: Research Funding. Mufti:Celgene Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Cellectis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Fenaux:Celgene Corporation: Honoraria, Research Funding; Astex: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Aprea: Research Funding. Buckstein:Takeda: Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Santini:Acceleron: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Menarini: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Honoraria. Díez-Campelo:Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Finelli:Celgene Corporation: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau. Sekeres:Syros: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. List:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Laadem:Celgene Corporation: Employment, Equity Ownership. Ito:Celgene Corporation: Employment, Equity Ownership. Zhang:Celgene Corporation: Employment, Equity Ownership. Rampersad:Celgene Corp: Employment, Equity Ownership. Sinsimer:Celgene Corporation: Employment, Equity Ownership. Linde:Fibrogen, Inc.: Equity Ownership; Abbott Laboratories, Inc.: Equity Ownership; Acceleron Pharma: Employment, Equity Ownership. Platzbecker:Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria. Komrokji:Alexion: Speakers Bureau; Incyte: Consultancy; Janssen: Consultancy; Agios: Consultancy; Celgene: Consultancy; Pfizer: Consultancy; Jazz: Speakers Bureau; DSI: Consultancy; Novartis: Speakers Bureau. OffLabel Disclosure: Luspatercept is an investigational therapy that is not approved for any use in any country. Luspatercept is currently being evaluated for potential use in patients with anemia due to myelodysplastic syndromes, beta-thalassemia, or myelofibrosis.

Description: Introduction: Anemia is the predominant cytopenia observed in patients with myelodysplastic syndromes (MDS), with many patients requiring regular red blood cell (RBC) transfusions. Erythropoiesis-stimulating agents (ESAs) remain a standard of care among patients with lower-risk MDS (LR-MDS), defined by International Prognostic Scoring System-Revised (IPSS-R) as Very Low-, Low-, or Intermediate-risk MDS, and endogenous serum erythropoietin (sEPO) levels ≤ 500 U/L. Recent studies of epoetin alfa and darbepoetin alfa have demonstrated efficacy among patients with LR-MDS, but the patient population in whom a clinically significant effect is seen may be limited (Fenaux P, et al. Leukemia 2018;32:2648-2658; Platzbecker U, et al. Leukemia 2017;31:1944-1950). A novel therapeutic option that increases the frequency of response and the duration of RBC transfusion independence (TI) in patients with LR-MDS would provide an important clinical benefit in this patient population. Luspatercept is a first-in-class erythroid maturation agent with a mechanism of action distinct from ESAs (Suragani RNVS, et al. Nat Med 2014;20:408-414). It is now approved in both the US and EU for patients with LR-MDS with ring sideroblasts (RS) who require RBC transfusions and are refractory, intolerant, or ineligible to receive ESAs on the basis of results from a phase 3 study (Fenaux P, Platzbecker U, et al. N Engl J Med 2020;382:140-151). Luspatercept may also be beneficial in treating anemia in patients with ESA-naive, LR-MDS who require RBC transfusions. In a phase 2 study in anemic patients with LR-MDS, 63% of patients receiving luspatercept (0.75-1.75 mg/kg) achieved a modified hematologic improvement - erythroid (mHI-E) response (Platzbecker U, et al. Lancet Oncol 2017;18:1338-1347); when analyzed by RS status, 69% of patients with ≥ 15% RS and 43% of patients with 〈 15% RS achieved mHI-E response. Study Design and Methods: The COMMANDS trial is a phase 3, open-label randomized study to compare the efficacy and safety of luspatercept versus epoetin alfa in anemic patients with IPSS-R defined LR-MDS, either with or without ≥ 15% RS, who are ESA naive, and who require regular RBC transfusions. Eligible patients must be aged ≥ 18 years at time of consent, have a documented diagnosis of IPSS-R defined LR-MDS with 〈 5% blasts in the bone marrow, have sEPO levels 〈 500 U/L, and require RBC transfusions (defined as an average transfusion requirement of 2-6 RBC units/8 weeks for ≥ 8 weeks immediately prior to randomization). Exclusion criteria include prior use of ESAs (≤ 2 doses of prior epoetin alfa permitted if ≥ 8 weeks from randomization date and sEPO confirmed as ≤ 500 U/L), granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF), unless given for the treatment of febrile neutropenia; disease-modifying agents (e.g. lenalidomide), or hypomethylating agents; and presence of del(5q) cytogenetic abnormality. A total of approximately 350 eligible patients will be randomized in a 1:1 ratio to receive either luspatercept (starting dose 1.0 mg/kg with titration up to 1.75 mg/kg) subcutaneously (SC) once every 3 weeks or epoetin alfa (starting dose 450 IU/kg with titration up to 1,050 IU/kg) SC once every week, for a minimum of 24 weeks (Figure). Best supportive care, including RBC transfusions, may be used in combination with study treatment in both arms. Randomization will be stratified by baseline RBC transfusion burden (〈 4 vs ≥ 4 RBC units per 8 weeks), RS status (with RS+ defined as RS ≥ 15%, or ≥ 5% [but 〈 15%] if SF3B1 mutation is present), and baseline sEPO level (≤ 200 U/L versus 〉 200 U/L). In addition, ≥ 40% and ≤ 60% of randomized patients will be RS+, and ≥ 25% will have sEPO 〉 200 U/L. The primary endpoint is the proportion of patients who achieve RBC-TI for 12 weeks within the first 24 weeks on study, with a concurrent mean hemoglobin (Hb) increase of ≥ 1.5 g/dL compared with baseline. Key secondary endpoints include duration of RBC-TI, change in Hb levels, achievement of HI-E response per International Working Group (IWG) 2006 criteria, and safety. The COMMANDS trial is registered at ClinicalTrials.gov (NCT03682536) and EudraCT (number 2017-003190-34). Disclosures Platzbecker: Takeda: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Geron: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; Amgen: Honoraria, Research Funding; BMS: Consultancy, Honoraria. Santini:Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Honoraria; Acceleron: Consultancy; Takeda: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Menarini: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees. Garcia-Manero:Celgene: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Acceleron Pharmaceuticals: Consultancy, Honoraria; H3 Biomedicine: Research Funding; AbbVie: Honoraria, Research Funding; Helsinn Therapeutics: Consultancy, Honoraria, Research Funding; Amphivena Therapeutics: Research Funding; Astex Pharmaceuticals: Consultancy, Honoraria, Research Funding; Novartis: Research Funding; Jazz Pharmaceuticals: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Onconova: Research Funding; Merck: Research Funding. Komrokji:Geron: Honoraria; Novartis: Honoraria; Incyte: Honoraria; JAZZ: Honoraria, Speakers Bureau; AbbVie: Honoraria; Agios: Honoraria, Speakers Bureau; Acceleron: Honoraria; BMS: Honoraria, Speakers Bureau. Ito:BMS: Current Employment, Current equity holder in publicly-traded company. Fenaux:BMS: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding.

Description: Introduction: LR-MDS are characterized by ineffective erythropoiesis that leads to anemia and red blood cell (RBC) transfusion dependence. Luspatercept is a first-in-class erythroid maturation agent that binds to select TGF-β superfamily ligands and enhances late-stage erythropoiesis. MEDALIST is a phase 3, randomized, double-blind, placebo-controlled trial to evaluate the safety and efficacy of luspatercept in pts with LR-MDS (IPSS-R-defined Very low-, Low-, and Intermediate-risk) with ring sideroblasts who required RBC transfusions and were ineligible for, intolerant of, or refractory to erythropoiesis-stimulating agents. Clinical benefit (CB; defined as RBC transfusion independence [RBC-TI] ≥ 8 weeks and/or modified hematologic improvement-erythroid [mHI-E] per IWG 2006 criteria) in the primary MEDALIST treatment phase (Weeks 1-24) was achieved by 58.2% of pts in the luspatercept arm and 21.1% in the placebo arm (P 〈 0.0001). The objective of the study was to investigate the effect of luspatercept treatment on erythropoiesis biomarkers and their relationship to CB in the primary MEDALIST treatment phase (Weeks 1-24). Methods: In the MEDALIST trial, 229 pts were randomized to receive either luspatercept (N = 153) or placebo (N = 76). Reticulocyte count was determined in blood samples collected at baseline and during the primary treatment phase. Serum biomarkers (soluble transferrin receptor 1 [sTfR1], erythroferrone [ERFE], and erythropoietin [EPO]) were measured by ELISA. Bone marrow (BM) erythroid precursors (EP) were determined by cytomorphology from BM aspirates. Biomarker levels were compared between baseline and Week 25 within treatment arms and between pts with CB and without CB in the luspatercept arm using a paired 2-tailed t-test and unpaired t-test (parametric method). Results: In the luspatercept arm, mean reticulocyte count increased from baseline, starting at 8 days after first dose (55.1 vs 34.5 × 109/L at baseline, P 〈 0.0001), and remained elevated throughout the evaluation period (Figure). Mean EPO levels increased significantly within 6 weeks after first dose (440.1 vs 220.4 IU/L at baseline, P 〈 0.0001) and remained elevated up to Week 25. Similarly, levels of sTfR1 (P 〈 0.0001), ERFE (P 〈 0.0001), and EP (P = 0.0010) were elevated at Week 25 relative to baseline (Table). The mean transfusion burden (within 16 weeks) was significantly reduced at Week 25 compared with baseline (7.2 vs 11.0 units, P 〈 0.0001). In contrast, in the placebo arm, reticulocyte count, EPO levels, and 16-week transfusion burden remained largely unchanged, while levels of sTfR1 (P 〈 0.0001), ERFE (P = 0.0431), and EP (P = 0.0010) were significantly lower at Week 25 relative to baseline. In the luspatercept arm, mean baseline EP were higher in 87 pts with CB (31.3%) compared with 63 pts without CB (26.5%; P = 0.0298). No statistically significant differences in baseline EPO, ERFE, sTfR1, reticulocyte count, and 16-week transfusion burden were observed in either group. At Week 25, pts with luspatercept and CB had a significantly greater increase of reticulocyte count (2.7 vs 1.8 mean fold increase from baseline, P = 0.0017), but not EPO levels (2.9 vs 4.3 mean fold increase from baseline, P = 0.1370) compared with pts without CB. Changes in erythropoiesis-related biomarkers (EP, ERFE, and sTfR1) did not differ significantly between pts with and without CB. To investigate whether luspatercept affects erythroid maturation, the ratio of reticulocyte/sTfR1 was calculated. This ratio was reasoned to be an approximation of the ratio of late-stage erythropoiesis (reticulocytes) within total erythropoiesis (sTfR1). Luspatercept increased the mean ratio of reticulocyte/sTfR1 in pts with CB (2.2 in Week 25 vs 1.5 at baseline, P 〈 0.0001) and no CB (1.9 in week 25 vs 1.3 at baseline, P = 0.0071). Conclusions: Luspatercept-treated pts in the MEDALIST trial had an increase of erythropoiesis-associated biomarkers. Luspatercept-mediated CB (RBC-TI ≥ 8 weeks and/or mHI-E) was associated with increased blood reticulocyte counts and was higher in pts with expanded BM erythropoiesis (as measured by EP) at baseline. Together with the observation that the ratio of reticulocytes/sTfR1 increased during luspatercept treatment, this suggests that the luspatercept mechanism of efficacy in pts with LR-MDS is associated with an increase of erythroid maturation and reticulocytes. Disclosures Platzbecker: Novartis: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Geron: Consultancy, Honoraria; Amgen: Honoraria, Research Funding. Zhu:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ha:Bristol Myers Squibb: Current Employment. Risueño:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: Named in BMS (before Celgene) patent filings related to predictive patient response biomarkers in hematological malignancies. Chan:Bristol Myers Squibb: Current Employment. Zhang:BMS: Current Employment. Dunshee:Bristol Myers Squibb: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Genentech Inc.: Current Employment, Current equity holder in publicly-traded company. Acar:Bristol Myers Squibb: Ended employment in the past 24 months. Shetty:BMS: Current Employment, Current equity holder in publicly-traded company. Ito:BMS: Current Employment, Current equity holder in publicly-traded company. MacBeth:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Santini:Menarini: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Acceleron: Consultancy; Novartis: Consultancy, Honoraria; Johnson & Johnson: Honoraria; BMS: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Garbowski:Imara: Consultancy; Vifor Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees. Fenaux:BMS: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Schwickart:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company.

Description: Introduction: Patients (pts) with MDS/MPN-RS-T have limited treatment options for anemia due to ineffective erythropoiesis. Luspatercept, the first-in-class erythroid maturation agent that enhances late-stage erythropoiesis, is approved by the FDA for treatment of anemia in adult pts with lower-risk (LR) MDS with ring sideroblasts (RS) or MDS/MPN-RS-T after erythroid-stimulating agent (ESA) failure. In the randomized, double-blind, phase 3 MEDALIST study, luspatercept significantly reduced transfusion burden vs placebo in pts with LR-MDS (NCT02631070; Fenaux P, et al. N Engl J Med 2020;382:140-51). Here, we assess the efficacy and safety of luspatercept in pts with MDS/MPN-RS-T enrolled in the MEDALIST study. Methods: Eligible pts were ≥ 18 years; had IPSS-R-defined Very low-, Low-, or Intermediate-risk MDS with RS; were refractory, intolerant, or unlikely to respond to ESAs (serum erythropoietin 〉 200 U/L); and required regular RBC transfusions. Pts were randomized 2:1 to luspatercept (1.0 mg/kg, titration to 1.75 mg/kg) or placebo administered subcutaneously every 3 wks. The primary endpoint was achievement of RBC transfusion independence (RBC-TI) ≥ 8 wks during Wks 1-24. Results: A retrospective analysis identified 23/229 (10.0%) pts enrolled in the MEDALIST trial who had MDS/MPN-RS-T, per WHO 2016 criteria (Arber DA, et al. Blood 2016;127:2391-405); 14 received luspatercept and 9 received placebo. Pts in this subgroup received a median of 4.0 RBC units/8 wks (range 2.0-11.5) during the 16 wks prior to treatment. At baseline, pts had a median hemoglobin (Hb) level of 7.7 g/dL (range 7.0-9.0), a median leukocyte count of 5.1 × 109/L, a median platelet count of 447.0 × 109/L, and 18 (78.3%) pts had serum erythropoietin levels 〈 200 U/L (Table). In the luspatercept arm, 9/14 (64.3%) pts with MDS/MPN-RS-T achieved the primary endpoint of RBC-TI for ≥ 8 wks during Wks 1-24, compared with 2/9 pts (22.2%) receiving placebo (odds ratio 11.3; 95% confidence interval [CI] 1.19, 106.12; P = 0.028). Pts receiving luspatercept were significantly more likely to achieve clinical benefit (achieving RBC-TI ≥ 8 wks and/or modified hematologic improvement-erythroid [mHI-E] per IWG 2006 criteria [≥ 4 units/8 wks reduction in RBC transfusion in pts with ≥ 4 units/8 wks baseline RBC transfusion burden; Hb increase by ≥ 1.5 g/dL] during Wks 1-24 in pts with 〈 4 units/8 wks baseline RBC transfusion burden), compared with pts receiving placebo (78.6% vs 33.3%; P = 0.034). Median time from the start of clinical benefit response to end of treatment was 94.6 wks (range 8.0-150.0) in the luspatercept arm and 23.9 wks (range 23.7-57.9) in the placebo arm. During Wks 1-24, mHI-E was achieved by 10 luspatercept pts (6 were high transfusion burden [HTB; defined as baseline transfusion burden ≥ 4 units/8 wks] and 4 were low transfusion burden [LTB; defined as baseline transfusion burden 〈 4 units/8 wks]) and 1 placebo pt (1/5 HTB). RBC-TI ≥ 8 wks was achieved by 4/8 HTB pts receiving luspatercept (vs 0/5 placebo) and 5/6 LTB pts (vs 2/4 placebo). After 24 wks, pts in the luspatercept arm had a mean Hb increase of +1.7 g/dL compared with an increase of +0.9 g/dL in pts in the placebo arm (least squares [LS] mean difference +0.85 g/dL; 95% CI −1.13, +2.82). Greater reductions from baseline in mean serum ferritin levels were seen with luspatercept (−121.8 μg/L) compared with placebo (−91.9 μg/L) over Wks 9-24 (LS mean difference −90.1; 95% CI −758.4, 578.2). Pts in the luspatercept arm had median platelet counts of 467.5 × 109/L and median leukocyte counts of 6.5 × 109/L post 24 wks of treatment, compared with pts in the placebo arm with 514.0 × 109/L and 6.2 × 109/L, respectively. The incidence of specific TEAEs (occurring in ≥ 1 patient) are as follows: fatigue (1/14 [7.1%] luspatercept vs 1/9 [11.1%] placebo), dizziness (7/14 [50.0%] vs 0/9), dyspnea (3/14 [21.4%] vs 0/9), nausea (6/14 [42.9%] vs 2/9 [22.2%]), arthralgia (1/14 [7.1%] vs 0/9), diarrhea (6/14 [42.9%] vs 1/9 [11.1%]), and hypertension (3/14 [21.4%] vs 0/9). In the luspatercept arm, 1/14 (7.1%) pts experienced ≥ 1 thromboembolic event (transient ischemic attack) and 1/9 (11.1%) pts in the placebo arm progressed to AML (as of July 1, 2019). Conclusions: Luspatercept demonstrated clinical efficacy in pts with MDS/MPN-RS-T with a generally well-tolerated safety profile. These data support the clinical benefits of luspatercept in this patient population with otherwise limited treatment options. Disclosures Komrokji: Geron: Honoraria; Novartis: Honoraria; Incyte: Honoraria; JAZZ: Honoraria, Speakers Bureau; AbbVie: Honoraria; Agios: Honoraria, Speakers Bureau; Acceleron: Honoraria; BMS: Honoraria, Speakers Bureau. Platzbecker:Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Geron: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Honoraria, Research Funding. Fenaux:BMS: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Jazz: Honoraria, Research Funding. Garcia-Manero:Helsinn Therapeutics: Consultancy, Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Amphivena Therapeutics: Research Funding; Jazz Pharmaceuticals: Consultancy; H3 Biomedicine: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Acceleron Pharmaceuticals: Consultancy, Honoraria; Novartis: Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Onconova: Research Funding; Astex Pharmaceuticals: Consultancy, Honoraria, Research Funding; Merck: Research Funding. Mufti:Abbvie, Novartis: Consultancy; BMS, Novartis: Research Funding. Santini:Janssen: Research Funding; BMS, J&J, Novartis: Honoraria; Acceleron, BMS, Menarini, Novartis: Consultancy; Takeda, Pfizer: Membership on an entity's Board of Directors or advisory committees. Diez-Campelo:Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Finelli:BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees. Jurcic:AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Syros Pharmaceuticals: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Arog Pharmaceuticals: Research Funding; Astellas: Research Funding; Forma Therapeutics: Research Funding; Genentech: Research Funding; Kura Oncology: Research Funding; PTC Therapeutics: Research Funding. Greenberg:BMS: Research Funding; Aprea: Research Funding; Notable Labs: Research Funding; H3 Biotech: Research Funding. Sekeres:BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda/Millenium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees. Zeidan:Abbvie: Consultancy, Honoraria, Research Funding; Otsuka: Consultancy, Honoraria; Trovagene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; Leukemia and Lymphoma Society: Other; CCITLA: Other; Astex: Research Funding; MedImmune/Astrazeneca: Research Funding; Ionis: Consultancy, Honoraria; Epizyme: Consultancy, Honoraria; Aprea: Research Funding; ADC Therapeutics: Research Funding; Taiho: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Cardinal Health: Consultancy, Honoraria; Daiichi Sankyo: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Jazz: Consultancy, Honoraria; Cardiff Oncology: Consultancy, Honoraria, Other; Agios: Consultancy, Honoraria; BeyondSpring: Consultancy, Honoraria; Incyte: Consultancy, Honoraria, Research Funding; Acceleron: Consultancy, Honoraria; Celgene / BMS: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding. DeZern:Astex: Research Funding; Celgene: Consultancy, Honoraria; MEI: Consultancy; Abbvie: Consultancy. Savona:Incyte: Consultancy, Research Funding; Sunesis: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; BMS: Consultancy; AbbVie: Consultancy; Gilead: Consultancy; Karyopharm: Consultancy, Current equity holder in publicly-traded company; Ryvu: Consultancy; Boehringer Ingelheim: Patents & Royalties; Astex: Consultancy, Research Funding; Takeda: Consultancy, Research Funding. Shetty:BMS: Current Employment, Current equity holder in publicly-traded company. Ito:BMS: Current Employment, Current equity holder in publicly-traded company. Zhang:BMS: Current Employment. Ha:BMS: Current Employment. Sinsimer:BMS: Current Employment, Current equity holder in publicly-traded company. Backstrom:BMS: Current equity holder in publicly-traded company; Acceleron Pharma: Current Employment, Current equity holder in publicly-traded company. Verma:BMS: Consultancy, Research Funding; acceleron: Consultancy, Honoraria; Janssen: Research Funding; Medpacto: Research Funding; stelexis: Current equity holder in private company.

Description: Introduction: Patients with myelodysplastic syndromes (MDS) experience severe anemia, which is commonly managed with frequent red blood cell transfusions (RBCT) in patients refractory to erythropoiesis-stimulating agents. At diagnosis, 85% of patients have anemia and 30-50% depend on RBCT. The administration of RBCT itself provides transient relief in anemia-related symptoms. Per protocol, MEDALIST investigators were advised to transfuse for symptoms related to anemia at the investigators' discretion. Hence, cessation or reduction of RBCT may increase anemia-related symptoms and negatively impact health-related quality of life (HRQoL). Luspatercept is a first-in-class erythroid maturation agent providing clinically meaningful reduction in transfusion burden in patients with transfusion-dependent anemia due to Revised International Prognostic Scoring System (IPSS-R)-defined Very low-, Low-, or Intermediate-risk MDS with ring sideroblasts in the phase 3 MEDALIST trial (NCT02631070). However, the impact of luspatercept on patients' HRQoL has not been evaluated. This analysis aimed to evaluate the effect of luspatercept versus placebo on HRQoL of patients treated for MDS from baseline through Week 25 of the MEDALIST study. Methods: Patients received luspatercept or placebo every 3 weeks for 24 weeks, plus best supportive care (BSC), including tailored amounts of RBCT. Effects of luspatercept versus placebo on HRQoL were evaluated as secondary and exploratory endpoints in the MEDALIST study. In the primary analysis, mean change from baseline to Week 25 (clinical assessment visit) in the European Organisation for Research and Treatment of Cancer's core quality of life questionnaire, version 3.0 (EORTC QLQ-C30) and in the QoL assessment in MDS questionnaire (QOL-E) was determined using mixed-effects repeated measures analysis. Clinically meaningful change within each treatment arm was defined as a ≥ 10-point change in patient-reported outcome (PRO) score from baseline for all EORTC QLQ-C30 domains, and ≥ 0.5 standard deviation of the baseline domain score for all QOL-E domains. Differences between luspatercept and placebo were considered clinically meaningful if the change from baseline between treatment arms exceeded the threshold for a clinically meaningful difference. In an exploratory analysis, patient-reported impact of transfusion dependence and overall side effects on their daily life was estimated using the QOL-E instrument. Results: A total of 229 patients were randomized; 153 patients to luspatercept and 76 to placebo. The HRQoL-evaluable population, consisting of patients with ≥ 1 post-baseline HRQoL score, was 149 patients in the luspatercept arm and 76 patients in the placebo arm. Questionnaire compliance rates among patients remaining on treatment were similar between luspatercept and placebo treatment groups at Week 25 (EORTC QLQ-C30, 88.2% vs 79.4% and QOL-E, 72.5% vs 69.7%). At baseline, MEDALIST patients had a clinically meaningfully worse HRQoL compared with the general population in 5 of 15 EORTC QLQ-C30 domains: physical functioning, role functioning, social functioning, fatigue, and dyspnea. Through Week 25, there was no clinically meaningful difference in change from baseline between and within the luspatercept and placebo arms across all EORTC QLQ-C30 (Global health status shown in Figure A) and QOL-E domains. A greater proportion of patients in the luspatercept arm relative to placebo reported improvements in daily life from the impact of transfusion burden (Figure B). Relative to baseline, the proportion of patients reporting a lower impact of transfusion dependence on their daily life was 39% versus 22% in luspatercept versus placebo at Week 25; in contrast, the proportion of patients reporting a higher impact of transfusion dependence on their daily life was 12% versus 22% in luspatercept versus placebo. Impact of treatment side effects on patients was comparable between luspatercept and placebo. Conclusions: Luspatercept with BSC reduced RBCT burden and patient-reported transfusion impact on their daily life, while maintaining other aspects of HRQoL from baseline through Week 25 in the MEDALIST study. Disclosures Oliva: Alexion: Consultancy; BMS: Consultancy, Honoraria, Patents & Royalties, Speakers Bureau; Novartis: Consultancy; Amgen: Consultancy; Abbvie: Consultancy; Apellis: Consultancy. Platzbecker:Takeda: Consultancy, Honoraria; Geron: Consultancy, Honoraria; Amgen: Honoraria, Research Funding; BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria. Garcia-Manero:Bristol-Myers Squibb: Consultancy, Research Funding; AbbVie: Honoraria, Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Helsinn Therapeutics: Consultancy, Honoraria, Research Funding; Onconova: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Merck: Research Funding; Acceleron Pharmaceuticals: Consultancy, Honoraria; Amphivena Therapeutics: Research Funding; Novartis: Research Funding; Astex Pharmaceuticals: Consultancy, Honoraria, Research Funding; Jazz Pharmaceuticals: Consultancy; H3 Biomedicine: Research Funding. Mufti:BMS, Novartis: Research Funding; Abbvie, Novartis: Consultancy. Santini:Takeda, Pfizer: Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Acceleron, BMS, Menarini, Novartis: Consultancy; BMS, J&J, Novartis: Honoraria. Sekeres:BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda/Millenium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees. Komrokji:BMS: Honoraria, Speakers Bureau; Acceleron: Honoraria; Geron: Honoraria; Agios: Honoraria, Speakers Bureau; AbbVie: Honoraria; JAZZ: Honoraria, Speakers Bureau; Incyte: Honoraria; Novartis: Honoraria. Shetty:BMS: Current Employment, Current equity holder in publicly-traded company. Tang:BMS: Current Employment, Current equity holder in publicly-traded company. Guo:BMS: Consultancy. Zhang:BMS: Current Employment. Ha:Bristol Myers Squibb: Current Employment. Ito:BMS: Current Employment, Current equity holder in publicly-traded company. Lord-Bessen:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Backstrom:BMS: Current equity holder in publicly-traded company; Acceleron Pharma: Current Employment, Current equity holder in publicly-traded company. Fenaux:Novartis: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding.