Red Blood Cell Transfusion Dependence Research Articles

Imetelstat in patients with lower-risk myelodysplastic syndromes who have relapsed or are refractory to erythropoiesis-stimulating agents (IMerge): a multinational, randomised, double-blind, placebo-controlled, phase 3 trial

Unmet medical needs remain in patients with red blood cell transfusion-dependent (RBC-TD) lower-risk myelodysplastic syndromes (LR-MDS) who are not responding to or are ineligible for erythropoiesis-stimulating agents (ESAs). Imetelstat, a competitive telomerase inhibitor, showed promising results in a phase 2 trial. We aimed to compare the RBC transfusion independence (RBC-TI) rate with imetelstat versus placebo in patients with RBC-TD LR-MDS. In phase 3 of IMerge, a double-blind, placebo-controlled trial conducted in 118 sites including university hospitals, cancer centres, and outpatient clinics in 17 countries, patients (aged ≥18 years) with ESA-relapsed, ESA-refractory, or ESA-ineligible LR-MDS (low or intermediate-1 risk disease as per International Prognostic Scoring System [IPSS] criteria) were randomly assigned via a computer-generated schedule (2:1) to receive imetelstat 7·5 mg/kg or placebo, administered as a 2-h intravenous infusion, every 4 weeks until disease progression, unacceptable toxic effects, or withdrawal of consent. Randomisation was stratified by previous RBC transfusion burden and IPSS risk group. Patients, investigators, and those analysing the data were masked to group assignment. The primary endpoint was 8-week RBC-TI, defined as the proportion of patients without RBC transfusions for at least 8 consecutive weeks starting on the day of randomisation until subsequent anti-cancer therapy, if any. Primary efficacy analyses were performed in the intention-to-treat population, and safety analyses were conducted in patients who received at least one dose of trial medication or placebo. This trial is registered with ClinicalTrials.gov (NCT02598661; substudy active and recruiting). Between Sept 11, 2019, and Oct 13, 2021, 178 patients were enrolled and randomly assigned (118 to imetelstat and 60 to placebo). 111 (62%) were male and 67 (38%) were female. 91 (77%) of 118 patients had discontinued treatment by data cutoff in the imetelstat group versus 45 (75%) in the placebo group; a further one patient in the placebo group did not receive treatment. Median follow-up was 19·5 months (IQR 12·0-23·4) in the imetelstat group and 17·5 months (12·1-22·7) in the placebo group. In the imetelstat group, 47 (40% [95% CI 30·9-49·3]) patients had an RBC-TI of at least 8 weeks versus nine (15% [7·1-26·6]) in the placebo group (rate difference 25% [9·9 to 36·9]; p=0·0008). Overall, 107 (91%) of 118 patients receiving imetelstat and 28 (47%) of 59 patients receiving placebo had grade 3-4 treatment-emergent adverse events. The most common treatment-emergent grade 3-4 adverse events in patients taking imetelstat were neutropenia (80 [68%] patients who received imetelstat vs two [3%] who received placebo) and thrombocytopenia (73 [62%] vs five [8%]). No treatment-related deaths were reported. Imetelstat offers a novel mechanism of action with durable transfusion independence (approximately 1 year) and disease-modifying activity for heavily transfused patients with LR-MDS who are not responding to or are ineligible for ESAs. Janssen Research & Development before April 18, 2019, and Geron Corporation thereafter.

Hematological Response to Frontline Treatment in Lower Risk Myelodysplastic Syndromes (LRMDS) Is Associated with Better Overall Survival

Background The majority of LRMDS patients (pts) (70%) do not progress but unfortunately succumb to complications related to cytopenia, namely anemia and red blood cell transfusion dependency (RBC-TD) or their interplay with co-morbidities. RBC-TD is associated with worse outcome reflecting bone marrow failure and long-term sequela of RBC-TD. There is growing evidence that response to treatment and RBC transfusion independence (TI) are associated with favorable outcome. In lieu of 2 recent randomized clinical trials demonstrating efficacy of luspatercept & imetelstat in LRMDS, we assessed the impact of response to sequential lines of treatment in LR-MDS on overall survival (OS) to guide our treatment choices and to determine whether erythroid stimulating agents (ESA) should still be our 1 st line of therapy. Methods We included LRMDS pts (IPSS-R very low & low) from Moffitt Database who received ESA as frontline therapy (FL) and assessed subsequently outcomes with second line (SL) therapy (SOC or clinical trial). We excluded MDS/MPN and del5q pts. We also excluded all pts who eventually progressed to either higher risk MDS or AML to better reflect the majority LRMDS in that disease state. We assessed details of FL and SL. Pts who received FL & SL were then divided into 4 groups based on response to FL and SL therapy: group 1 (no/no), group 2 (no/yes) with response only to SL, group 3 (yes/no) response to FL only, and group 4 (yes/yes) with response to both lines of therapy. Response was defined as hematological improvement (HI) with ≥1.5 g/dl Hgb increase in non-TD pts and RBC-TI in TD pts at baseline for at least for 8 weeks. We compared median OS (mOS) among those groups. Results There were 603 LRMDS pts who met eligibility criteria and received ESA as FL (Table-1); 43% were RBC-TD, mean serum EPO was 132 (n=211 pts), 69% received epoetin, 17% darbepoetin and 14% with G-CSF. HI was observed in 42% of pts with no difference among ring sideroblasts (RS) +/- (46% vs 40%, p =.12). Response was higher among non-RBC-TD (52% vs 31%, p< .001). The median time to start ESA was 1.2 mo (0-249). The median time on ESA therapy was 11 mo (.4-213). 331 pts (55%) received SL which included HMA 43% (n= 142), lenalidomide 39% (n=130), luspatercept 7% (n=24), ATG 2% (n=8), investigational agent 4% (n=14), and other 4% (n=13) . The HI rate was 27% (91/331). No difference in HI based on RS nor RBC-TD was observed. The median duration on SL treatment was 6 mo (.1-93). 170 pts (28%) received 3 rd line of therapy with 7% HI, 88 pts (15%) received 4 th line of therapy with 3% HI and 39 pts (7%) had 5 th line of therapy with 2% HI. Among the 331 pts who received at least FL and SL, pts were divided into 4 groups based on response to (methods, table-2), the mOS was 114 mo among Yes/Yes response group, 103 mo among yes/no group, 97 mo no/yes and 64 mo among no/no ( P=.007; Figure-1). Response to FL was significantly associated with better OS after adjusting for RS (HR .74 ,95% CI .55-.99, p=.043). Conclusions Only half of patients who receive ESA as FL therapy for LRMDS received any subsequent therapies. Response rates were highest with ESA as FL than any SL therapy. HI with FL and/or SL is associated with improved OS. Lack of response to first line of therapy is associated with worse OS. Responses beyond SL were rarely observed. Identifying and moving agents with high HI rate as FL therapy and or selecting option based on predictors of best chance of response to a specific treatment as FL may lead to better overall survival.

Durable Continuous Transfusion Independence (TI) with Imetelstat in IMerge Phase 3 for Patients with Heavily Transfused Non-Del(5q) Lower-Risk Myelodysplastic Syndromes (LR-MDS) Relapsed/Refractory (R/R) to or Ineligible for Erythropoiesis-Stimulating Agents (ESAs)

CONCLUSIONS MDS are serious life-threatening hematologic malignancies in which a heterogeneous group of clonal disorders results in ineffective hematopoiesis. An unmet need remains for new therapies for patients (pts) with LR-MDS who are red blood cell transfusion dependent (RBC-TD) and R/R to or ineligible for ESAs. Imetelstat, an oligonucleotide, is a first-in-class telomerase inhibitor that targets cells with high telomerase activity by direct binding to the RNA template of telomerase. In the IMerge phase 3 trial, imetelstat produced higher rates of TI for ≥8 weeks, ≥24 weeks, and ≥1 year (39.8%, 28.0%, and 17.8%) than placebo (15.0%, 3.3%, and 1.7%) in pts with non-del(5q) LR-MDS that was RBC-TD, R/R to/ineligible for ESAs, and naïve to lenalidomide or hypomethylating agents (HMAs; Platzbecker et al. EHA 2023. Abstr S165). We report characteristics and clinical benefit for pts with sustained TI for ≥1 year from this trial. IMerge (MDS3001, NCT02598661) is a global, double-blind, randomized, placebo-controlled, phase 3 trial of imetelstat in RBC-TD, ESA-R/R, non-del 5(q) lenalidomide/HMA-naïve LR-MDS. The primary end point was 8-week TI rate; secondary end points included safety, 24-week TI, duration of response, hematologic improvement, and MDS response. Exploratory end points included assessment of cytogenetic response and mutational status with clinical response. The proportion of pts with>1-year TI and other binary end points, were summarized with percentage and 95% 2-sided exact Clopper-Pearson CI. The Kaplan-Meier method was used to estimate the distribution of TI. Of 118 pts receiving imetelstat, 21 (17.8%; 95% CI, 11.4-25.9) achieved ≥1-year sustained TI, representing 45% of ≥8-week TI (21 of 47 pts) and 64% of ≥24-week TI (21 of 33 pts); of 60 pts receiving placebo plus supportive care, 1 (1.7%; 95% CI, 0-8.9) achieved ≥1-year TI. Of the ≥1-year TI imetelstat responders, 15/21 (71.4%) had ring sideroblasts, as did the 1 placebo pt. The median prior RBC transfusion burden was 6 U over 8 weeks (range, 4-9 U) for the imetelstat group and 5 U for the placebo pt. Additional baseline characteristics are in the table. Pts received imetelstat for a median of 101.1 weeks (range, 75.1-163.9 weeks) and a median of 24 cycles (range, 18-41 cycles). The median duration of TI for imetelstat ≥1-year TI responders was 123 weeks (95% CI, 80.4 to not evaluable); the median increase in hemoglobin during the longest TI interval was 5.18 g/dL (range, 2.67-13.76 g/dL) for the imetelstat group vs 1.67 g/dL for the placebo pt. After a median follow-up of 125 weeks, none of the patients with ≥1 year TI on either arm progressed to acute myeloid leukemia (AML). Of the pts receiving imetelstat, 7 had an abnormal karyotype at baseline, of which 6 had reduction in the cytogenetic abnormal clones (4 with cytogenetic complete response and 2 with cytogenetic partial response by independent review committee). Mutation data were available for 18 pts receiving imetelstat, all with SF3B1 mutations present at baseline, and multiple of these pts concurrently had TET2, DNMT3A, ASXL1, or JAK2 mutations. The maximal reduction ranged from −6% to −100% in SF3B1 variant allele frequency (VAF) in these pts, and 13 of 18 (72.2%) achieved ≥50% VAF reduction, including 7 with complete elimination of the VAF. Reduction in other concurrent mutations was also observed in these pts. Safety was consistent with that previously reported; most frequent adverse events were reversible grade 3 or 4 thrombocytopenia and neutropenia. At the time of data cutoff (May 10, 2023), 13 pts receiving imetelstat and the pt receiving placebo were ongoing (Figure); of the 8 who discontinued treatment, 7 had loss of response, and 1 was due to adverse event. Analyses for progression-free and overall survival were not evaluable as of this cutoff date (insufficient follow-up). Treatment with imetelstat resulted in ≥1-year sustained, continuous TI in 17.8% of pts in the IMerge phase 3 trial. In this ESA-R/R/ineligible population with a high prior transfusion burden, a reduction to 0 RBC transfusions for ≥1 year represents an opportunity to achieve relief from iron overload and other transfusion associated complications, and decreased demand on already limited blood product supply. Furthermore, durable TI and meaningful reductions in mutational burden suggest imetelstat may have disease-modifying activity.

Red Blood Cell Transfusion Dependence Is Associated with Greater Healthcare Resource Utilization, Higher Medical Cost, and Poorer Prognosis in Patients with Lower-Risk Myelodysplastic Syndromes: A 28-Year Retrospective Observation Study Result

Myelodysplastic syndromes (MDS) encompass a heterogeneous group of myeloid neoplasms characterized by cytopenia due to inefficient hematopoiesis, with a considerable risk of progression to acute myeloid leukemia (AML) or early mortality. In lower-risk MDS (LR-MDS) patients, anemia and its associated complications have been the focus of clinical attention. A significant portion of these patients eventually develop red blood cell transfusion dependence (RBC TD), which has been linked to a poorer prognosis. Given the limited efficacy of available treatments in reducing RBC TD, most patients face increased risks of chronic anemia and various complications. Moreover, RBC TD is known to be associated with reduced overall survival (OS) and leukemia-free survival (LFS). This study aimed to assess the impact of RBC TD on the socioeconomic burden and clinical prognosis of LR-MDS patients, utilizing an electronic medical records (EMR) database spanning nearly 30 years of MDS patient data. This retrospective observational study examined adult MDS patients (≥ 18 years of age) treated at Samsung Medical Center in the Republic of Korea. Eligible patients were diagnosed with MDS between Sep 1, 1994, to Apr 1, 2022 (index period), with the observation period spanning from Sep 1, 1994, to Sep 1, 2022. Baseline assessments included estimation of revised international prognostic scoring system (IPSS-R) scores, categorizing patients with very low, low or intermediate risks as lower-risk MDS (LR-MDS). TD was defined as the occurrence of any 16-week period with RBC transfusion of ≥ 2 units per 8 weeks, without consecutive 56-day period without transfusion. Healthcare resource utilization (HCRU), medical costs, and prognosis indicators including overall survival (OS) and AML-free survival (AFS) were analyzed and compared between patients who experiencing TD and those not (non-TD). Out of 831 MDS patients, 349 (42.0%) were classified as lower-risk at baseline. Among LR-MDS patients, 29.5% (103/349) experienced TD while 23.3% (194/831) experienced TD in the entire study population. The median age at diagnosis of MDS was 63 (ranging from 18 to 89), and 65.3% (543/831) were male. In LR-MDS patients, there were no significant differences in either baseline age (61 vs 63, P=0.16) or gender (71.8% vs 61.0% males, P=0.053) between TD and non-TD groups. However, TD group exhibited significantly higher median erythropoietin (EPO) level than non-TD group (290.5U/L vs. 112U/L, P<0.001) among LR-MDS patients with available baseline serum EPO levels (76 TD and 178 non-TD). Among the 76 TD LR-MDS patients with baseline serum EPO levels, 51 (67.1%) exhibited > 200U/L, which is considered a clinical threshold for erythropoiesis-stimulating agent (ESA) treatment. As shown in Table 1, RBC TD was consistently associated with greater HCRU and higher medical costs, especially in LR-MDS patients. TD LR-MDS patients had higher rates of outpatient department and emergency room visits (15676 vs. 8303 visits and 587 vs. 328 visits per 1000 person-years [PY], respectively), and increased hospitalizations (709 vs. 456 per 1000 PY), with longer hospital stays (13343 vs. 8272 days per 1000 PY). Furthermore, TD LR-MDS patients required over four-times of packed RBC units than non-TD patients (31107 vs. 7073 units per 1000 PY). Consequently, TD LR-MDS patients incurred higher total medical cost than their non-TD counterpart (13.5 million vs. 6.1 million USD per 1000 PY). Median OS (58.4 months vs. 103.1 months) and AFS (52.7 months vs. 102.7 months) were both significantly shorter in the TD group compared to the non-TD group among LR-MDS patients, while the differences in OS and AFS did not reach the level of significance in the entire study population (Table 1 and Figure 1). Notably, median OS after the first documented RBC TD event was 33.8 months (95% confidence interval: 24.7-58.5 months) in LR-MDS patients. The findings of this study indicate that RBC TD can be a strong predictor of increased HCRU and medical costs, as well as decreased OS and AFS over a 20-year period following the initial diagnosis of LR-MDS. Given that a majority of LR-MDS patients experiencing TD may not be eligible for ESA treatment due to elevated EPO levels exceeding 200U/L, and the use of cytotoxic agents is not usually recommended for these patients, these results highlight a substantial unmet need for alternative treatment options to address RBC TD in LR-MDS patients.

Time without Transfusion Reliance or Anemia Worsening: A Novel Method for Integrating Transfusion Dependence, Anemia, and Survival with Myelofibrosis Therapies Based on the Phase 3 Simplify-1 and Simplify-2 Trials

Introduction: While approved Janus kinase inhibitors (JAKi) have improved overall survival (OS) in myelofibrosis (MF), traditional survival analyses do not consider individual patient (pt) experience, which may be negatively impacted by factors such as persistent symptoms, adverse events (AEs), and red blood cell (RBC) transfusion dependence. In particular, RBC transfusions, an important component of anemia management in MF with currently approved JAKi, are associated with negative quality of life (QOL), increased healthcare resource utilization, and poor prognosis. Momelotinib (MMB), a JAK1/JAK2/activin A receptor type 1 inhibitor, has demonstrated consistent anemia benefits, including increased transfusion independence and reduced transfusion burden, as well as spleen and symptom improvements across 3 phase 3 trials in MF. In the SIMPLIFY-1 (NCT01969838) and SIMPLIFY-2 (NCT02101268) trials, achieving transfusion independence with MMB was associated with prolonged OS (Mesa R, et al. Leukemia. 2022). Here we apply time without transfusion reliance (TWiTR) analyses, integrating transfusion-dependent (TD) status and OS, to further characterize the benefits of MMB on survival quality. Methods: Analyses were performed in the safety populations, by treatment arm, over the randomized 24-wk treatment period of SIMPLIFY-1 (n/N=430/432; MMB vs ruxolitinib [RUX], JAKi naive) and SIMPLIFY-2 (N=156; MMB vs best available therapy [BAT; 88.5% RUX], JAKi experienced). TWiTR (Zeidner JF, et al. Haematologica. 2023) was based on the established time without symptoms and toxicity (TWiST) analysis, replacing toxicity with TD status. The analysis partitioned survival duration into 3 health states: (1) TD, defined as the number of days on which pts were TD (defined per protocol in the SIMPLIFY studies as requiring ≥4 units of RBC transfusions or having a hemoglobin level <8 g/dL in the previous 8 weeks) before experiencing a leukemia-free survival (LFS) event (leukemic transformation or death); (2) Post-LFS, defined as the number of days from an LFS event to death or censoring (OS; Post-LFS = OS − LFS); and (3) TWiTR, defined as the number of days without Post-LFS or TD (TWiTR = LFS − TD). An additional analysis incorporated the number of days on which pts had any-grade anemia events in the TD state (TD-Anemia [TD-An]) to define time without transfusion reliance or anemia worsening (TWiTR-An). Health state durations were estimated via Kaplan-Meier curves of the survival distribution function, with mean duration in each state calculated as the area under the curve. Results: In SIMPLIFY-1, pts in the MMB arm spent less time in the TD state and more time in the TWiTR state vs pts in the RUX arm (Figure 1). Mean duration in the TD state was 28.3 vs 62.7 days (difference with MMB, −34.4 days), while mean duration in the TWiTR state was 163.4 vs 131.1 days with MMB vs RUX (difference with MMB, 32.3 days). Fewer pts in the MMB arm had treatment-emergent anemia AEs, and incorporation of anemia events into the analysis increased the mean time spent in the TD-An state compared with the TD state in both treatment arms, although this increase was smaller in the MMB arm, at 32.0 vs 74.8 days in the RUX arm (difference with MMB, −42.8 days). Mean duration in the TWiTR-An state was 159.7 vs 119.0 days with MMB vs RUX (difference with MMB, 40.7 days). Similar results were observed in SIMPLIFY-2, although incorporating anemia events had less impact. Mean duration in the TD state was slightly shorter with MMB vs BAT, at 69.4 vs 89.9 days (difference with MMB, −20.5 days); mean duration in the TD-An state was 69.6 vs 89.9 days (difference with MMB, −20.3 days). Consistently, mean duration in the TWiTR state was slightly longer with MMB vs BAT, at 118.3 vs 95.9 days (difference with MMB, 22.4 days); mean duration in the TWiTR-An state was 118.0 vs 95.9 days (difference with MMB, 22.1 days). Conclusions: Pts treated with MMB spent less time reliant on RBC transfusions and more time free from transfusions and anemia events, without the cost of increased AEs, compared with those treated with RUX or BAT. Given the negative QOL and prognostic impact of RBC transfusion dependence, these analyses suggest that the anemia benefits of MMB lead to improved quality of survival for pts with MF.

The ELEMENT-MDS Trial: A Phase 3 Randomized Study Evaluating Luspatercept Versus Epoetin Alfa in Erythropoiesis-Stimulating Agent-Naive, Non-Transfusion-Dependent, Lower-Risk Myelodysplastic Syndromes

Background and Significance: Anemia is a common and debilitating symptom in patients with myelodysplastic syndromes (MDS), frequently leading to dependence on red blood cell (RBC) transfusions. Transfusion-dependent (TD) patients have worse overall survival and quality of life, and repeat transfusions are associated with complications, including iron overload. Erythropoiesis-stimulating agents (ESAs) are the standard treatment for anemia in patients with lower-risk (LR)-MDS, but many patients are ineligible for or refractory to ESAs, and responses are limited. Luspatercept, a late-stage erythroid maturation agent, is approved to treat TD patients with LR-MDS after ESA failure. In the phase 3 COMMANDS study, in ESA-naive patients with LR-MDS requiring transfusions, a significantly higher proportion of patients receiving luspatercept than epoetin alfa achieved RBC transfusion independence for ≥ 12 weeks with concurrent hemoglobin (Hb) increase ≥ 1.5 g/dL (weeks 1-24) (Platzbecker U, et al. Lancet 2023. doi: 10.1016/S0140-6736(23)00874-7). The potential of luspatercept to improve moderately severe chronic anemia and reduce RBC transfusion dependence has not yet been investigated in the majority non-transfusion-dependent (NTD) LR-MDS patient population. Preventing transfusion dependence is crucial for improving LR-MDS patient outcomes. The aim of this actively enrolling, phase 3, randomized, multicenter study is to compare the safety and efficacy of luspatercept versus epoetin alfa in reducing progression to RBC transfusion dependence in ESA-naive, NTD adult patients with anemia due to LR-MDS. Study design and methods: The ELEMENT-MDS study includes a 5-week screening period, a 96-week treatment period, an extension phase, and a post-treatment follow-up period (Figure). Target enrollment is 360 patients with anemia due to Revised International Prognostic Scoring System (IPSS-R) Very low-, Low-, or Intermediate-risk MDS. Eligible patients are ≥ 18 years of age with a confirmed MDS diagnosis, baseline serum erythropoietin (sEPO) levels ≤ 500 U/L, and symptomatic anemia defined as a score of moderate or worse on ≥ 1 Patient Global Impression of Severity (PGI-S) item (fatigue, shortness of breath, weakness, or dizziness). Participants must be RBC transfusion-independent per International Working Group 2018 criteria (no RBC transfusions within 16 weeks prior to randomization) and have baseline Hb ≤ 9.5 g/dL. Patients will be excluded if they have a del(5q) cytogenetic abnormality, unclassifiable MDS or myelodysplastic/myeloproliferative neoplasms, anemia due to reasons other than MDS, bleeding disorders, low absolute neutrophil or platelet counts, uncontrolled hypertension, previous acute myeloid leukemia diagnosis, or history of recent malignancies, among other reasons. Participants will be randomized 1:1 to receive luspatercept or epoetin alfa. Stratification factors include baseline sEPO levels, ring sideroblast status, and IPSS-R risk category. Patients will receive luspatercept once every 3 weeks at a starting dose of 1.0 mg/kg (escalation up to 1.75 mg/kg allowed) or epoetin alfa once a week at a starting dose of 450 IU/kg (escalation up to 1050 IU/kg allowed). The primary endpoint will compare the proportion of patients becoming TD (defined as requiring ≥ 3 RBC units/16 weeks) during any continuous 16-week interval in weeks 1-96. The key secondary endpoint is a Hb increase ≥ 1.5 g/dL sustained for ≥ 16 weeks during weeks 1-48. Additional secondary endpoints include time to RBC transfusion dependence, transfusion-free survival, time to achieve modified hematologic improvement-erythroid response, transfusion independence ≥ 24 weeks, and quality of life assessment. Safety endpoints include type and severity of adverse events and relationship to treatment, overall survival, and progression to high-risk MDS and acute myeloid leukemia. Summary: The results of this phase 3 study will determine the efficacy and safety of luspatercept as a therapy for ESA-naive NTD patients with LR-MDS, who have limited treatment options for anemia. The study is registered at ClinicalTrials.gov (NCT05949684) and EudraCT (2022-500430-29-00).

Characterization and Management of Cytopenias after Imetelstat Treatment in the IMerge Phase 3 Trial of Patients with Lower-Risk Myelodysplastic Syndromes (LR-MDS)

CONCLUSIONS Imetelstat, an oligonucleotide and a first-in-class telomerase inhibitor, selectively targets malignant hematopoietic stem and progenitor cells with high telomerase activity by direct binding to the RNA template. In patients with MDS the on-target effects of imetelstat are associated with the development of hematologic treatment-emergent adverse events (TEAEs). In the IMerge phase 3 trial, among patients treated with imetelstat, 68% experienced grade 3-4 neutropenia, and 62% had grade 3-4 thrombocytopenia; however, clinical consequences of grade 3-4 infection or bleeding were similar in patients treated with imetelstat and placebo (Platzbecker et al. EHA 2023. Abstr S165). Here, we report additional data on the occurrence and management of cytopenias after treatment with imetelstat. IMerge phase 3 trial (NCT02598661) is a multicenter study involving 178 patients with a median age of 72 years with red blood cell (RBC) transfusion dependency and LR-MDS relapsed/refractory to or ineligible for erythropoiesis-stimulating agents. Patients were randomized 2:1 to receive either imetelstat or placebo and stratified by prior RBC transfusion burden (4-6 or >6 U) and by International Prognostic Scoring System risk group. The safety population included all patients who received ≥1 dose of study drug and comprised 118 patients treated with imetelstat and 59 with placebo. TEAEs of neutropenia and thrombocytopenia with imetelstat treatment were more prevalent in cycles 1-3 (68.6% and 62.7% respectively), and their frequency decreased over time: 42.7% and 48.5% in cycles 4-6, 36.8% and 44.7% in cycles 7-12, and 31.3% and 37.5% in cycle 13 and beyond. Based on laboratory assessment, neutrophil and platelet counts decreased from baseline levels in patients treated with imetelstat versus those treated with placebo (91.5% and 95.8% vs 47.5% and 33.9%, respectively). Neutropenia decreased to a maximum of grade 4 and 3 in 55 and 29 of imetelstat-treated patients, respectively, and >80% of cytopenia events stabilized to grade ≤2 within 4 weeks (Figure). The median time to grade 4 neutropenia was 5.0 weeks (range,1.1-90.3 weeks) for the imetelstat group vs 23.0 weeks (range, 23.0-23.0 weeks) for the placebo group. Similarly, median time to grade 4 thrombocytopenia was 5.2 weeks (range, 2.0-29.9 weeks) with imetelstat vs 35.5 weeks (range, 28.0-43.0 weeks) with placebo. It is noteworthy that among 47 patients who achieved the primary end point of 8-week RBC transfusion independence with imetelstat, 34 (72.3%) and 28 patients (59.6%) had grade 3-4 neutropenia and grade 3-4 thrombocytopenia, respectively. In the imetelstat group, 3 patients had grade 3-4 neutropenia concurrent with grade 3-4 infections, and no patients experienced grade 3-4 thrombocytopenia associated with grade 3-4 bleeding events. There were no grade 5 cytopenias for either imetelstat or placebo groups. In the imetelstat group, cytopenias were managed with protocol-specified treatment delays and dose adjustments. Dose reductions due to neutropenia and thrombocytopenia occurred in 39 patients (33.1%) and 27 patients (22.9%), respectively. Of imetelstat-treated patients, 6 (5.1%) discontinued treatment due to neutropenia (1 case, grade 4; all others, grade 3), and 4 (3.4%) discontinued due to thrombocytopenia (1 case, grade 2; 3 cases, grade 3). In addition to dose reductions and discontinuation of imetelstat, thrombocytopenia and neutropenia were managed by cycle delays in 46.6% and 50.8% of patients, by platelet transfusions in 17.8% of patients, and by concomitant therapy with growth factor support (mostly during cycles 2-4) in 34.7% of patients. Similar patterns of imetelstat dose modifications were seen in a pooled phase 2 and phase 3 safety analysis of IMerge. In the IMerge phase 3 trial, thrombocytopenia and neutropenia were the most common and most frequently reported grade 3-4 AEs during treatment cycles 1-3. However, these AEs were generally transient, reversible, and manageable through treatment delays and dose adjustments, allowing for patients to remain on treatment and continue to experience clinical benefit. Moreover, occurrence of grade 3-4 cytopenias in responders suggests that these TEAEs do not affect the efficacy of imetelstat.

Efficacy and Safety of Roxadustat for Treatment of Anemia in Patients with Lower-Risk Myelodysplastic Syndrome (LR-MDS) with Low Red Blood Cell (RBC) Transfusion Burden: Results of Phase III Matterhorn Study

Presented on behalf of all MATTERHORN (FGCL-4592-082) study investigators Introduction: For patients (pts) with LR-MDS, anemia poses a major clinical challenge, with limited response to first-line erythropoietin (EPO)-stimulating agents (ESAs) and a median duration of response ≤2 years. Further, pts with RBC transfusion dependence (≥2 packed RBC [pRBC] units every 8 weeks [Q8W]) are less likely to respond to ESAs. Anemia treatments with novel mechanisms of action enabling transfusion independence (TI) are needed to reduce frequent RBC transfusion burden. Roxadustat is a first-in-class, hypoxia-inducible factor prolyl hydroxylase inhibitor for treatment of anemia with chronic kidney disease. In the MATTERHORN (NCT03263091) dose-selection stage, roxadustat was well-tolerated, and 37.5% of pts (9/24) with LR-MDS and low RBC transfusion burden ([LTB] 1 pRBC unit Q8W for two consecutive 8-week periods or 2-4 pRBC units Q8W) achieved TI. In the MATTERHORN double-blind stage, TI response rate and safety of roxadustat were further assessed. Methods: MATTERHORN is an ongoing, double-blind, Phase III, randomized, placebo (PBO)-controlled trial. Eligible adult pts (≥18 years of age) had very low-, low-, or intermediate-risk primary MDS per Revised International Prognostic Scoring System (IPSS-R) classification (<5% bone marrow blasts); hemoglobin (Hb) ≤10.0 g/dL at baseline (BL); and LTB. Prior ESA use (>8 weeks before randomization) was permitted. Pts were randomized 3:2 to roxadustat or PBO, then stratified by serum EPO concentration (≤200 or 200-400 mIU/mL), IPSS-R risk, and transfusion burden. Pts received oral roxadustat (starting dosage: 2.5 mg/kg three times weekly based on the dose-selection stage) or PBO with best supportive care (BSC; per institutional criteria, including RBC transfusion) for a 52-week treatment period, followed by a 4-week follow-up period. Primary efficacy endpoint was percentage of pts with TI (the absence of RBC transfusion) for ≥56 consecutive days during the first 28 treatment weeks (TI responder). The percentage of pts with TI and mean Hb increase of ≥1.0 and ≥1.5 g/dL (averaged over 8 weeks) compared with BL pretransfusion Hb was also assessed (to be reported separately). Safety (including treatment-emergent adverse events [TEAEs] and serious TEAEs) was evaluated throughout the study. Results: As of the final 28-week interim analysis of the double-blind stage (data cutoff: April 24, 2023), 140 pts (82 roxadustat, 58 PBO) were randomized and treated. Across arms, median age was 71.5 years (range, 26-96), 59.3% (83/140) were male, and 80.0% (112/140) were white. Most pts (72.1% [101/140]) had IPSS-R low-risk disease and a transfusion burden of 2-4 pRBC units Q8W (92.1% [129/140]). Median (range) BL transfusion burden was 2.5 (1-10) pRBC units. Seventy pts (50.0%) received prior ESAs (98.6% [69/70] were ESA-refractory). Eighty-four pts (41/82 [50.0%] roxadustat, 43/58 [74.1%] PBO) completed 28 weeks of treatment, and 15 pts (6/82 [7.3%] roxadustat, 9/58 [15.5%] PBO) were continuing treatment. Median (range) treatment duration was 24.1 (1.1-28.0) weeks for the roxadustat arm and 28.0 (0.1-28.0) weeks for the PBO arm. A greater percentage of pts in the roxadustat arm compared with the PBO arm were TI responders (47.5% vs. 33.3%). However, this difference did not reach statistical significance ( p=0.22; figure). Percentages of pts with TEAEs of any grade, serious TEAEs, and TEAEs leading to treatment discontinuation were similar across arms (table). Six deaths occurred on study (roxadustat: pneumonia [n=2], acute myocardial infarction and ischemic stroke [n=1], multiorgan failure [n=1]; PBO: urosepsis [n=1], disease progression [n=1]). Three pts (all in roxadustat arm) progressed to acute myeloid leukemia. The study was terminated by the sponsor and is currently being completed. Conclusions: Despite not meeting the primary endpoint, roxadustat plus BSC was well-tolerated, and a high percentage of pts with LR-MDS and LTB were TI responders. The high TI response rate in the PBO arm, historically poor outcomes in pts with ESA-refractory disease, and the inclusion of pts who were not transfusion-dependent (1 pRBC unit Q8W) may have contributed to the lack of a statistically significant difference in TI response rates between arms. MATTERHORN outcomes highlight the continued unmet need for effective and safe therapies that reduce RBC transfusion burden in LR-MDS.

Real-World Characteristics, Treatment Utilization, and Transfusion Burden in Patients with β-Thalassemia Initiating Luspatercept: A US Cohort Study

Introduction: β-thalassemia is a β-globin gene disorder resulting in decreased production of hemoglobin A and chronic anemia. Disease severity ranges from asymptomatic, mild anemia to life-long red blood cell transfusion dependence. Luspatercept is an erythroid maturation agent that reduces transfusion burden in patients with transfusion-dependent β-thalassemia. We describe real-world baseline demographics and clinical characteristics alongside treatment utilization patterns in US patients with β-thalassemia treated with luspatercept. Methods: This retrospective, observational, cohort study used Komodo Health's Healthcare Map, a large administrative claims database in the USA. Patients with a diagnosis of β-thalassemia (ICD-10 code: D56.1) who initiated luspatercept treatment between January 1, 2020 and September 30, 2021 were included; the full study period was July 1, 2019 to September 30, 2022. The index date was defined as the first documented administration of luspatercept during the identification period. Patients were adults (≥ 18 years of age on index date) continuously enrolled for 6 months before (baseline) and 12 months after (follow-up) the index date. Discontinuation was defined as no medication claim for ≥ 90 days (assuming a 3-week schedule while taking into account potential dose delays). Descriptive statistics were used to analyze and report baseline demographics and clinical characteristics. Time-to-event variables were assessed using Kaplan-Meier methods. Results: The 101 patients included had a mean (standard deviation [SD]) age of 37.7 (14.9) years, with a broad geographical spread throughout the USA (Midwest n = 17, 16.8%; Northeast n = 24, 23.8%; South n = 28, 27.7%; West n = 32, 31.7%). Approximately half (52.5%) were female, and mainly commercially insured (56.4%). Patients were in relatively good health (mean [SD] Charlson Comorbidity Index: 0.8 [1.7]). Bone deformities (n = 16, 15.8%), hepatosplenomegaly (n = 13, 12.9%), and thrombotic events (n = 10, 9.9%) were the most common β-thalassemia-related comorbidities observed in the baseline period. Median (interquartile range) baseline transfusion frequency during the 6-month baseline period was 4.0 (8.0), and 55.0% of the patients were transfusion dependent (≥ 4 transfusions in the 6-month baseline period). Over 40% of patients remained on luspatercept after 1 year of treatment with a median time to discontinuation of 96.5 days (Figure). Approximately one fifth (19.0%) of patients who discontinued luspatercept reinitiated treatment (Figure). Among those who were transfusion-dependent who stayed on luspatercept at 6 months, 31.3% (10/32) experienced a reduction in the frequency of transfusions, with a median decrease of 2 visits in the 6-month follow-up period from baseline, and 28.1% (9/32) observed a decrease in the units of blood transfused, with a median decrease of 5 units in the 6-month follow-up period from baseline (Table). Similarly, among patients who were transfusion-dependent who stayed on luspatercept for 12 months, 32.0% (8/25) experienced a reduction in the frequency of transfusions, with a median decrease of 2.5 visits in the follow-up period from baseline, and 48.0% (12/25) observed a decrease in the units of blood transfused, with a median decrease of 3.7 units in the 12 month follow-up period from baseline (Table). Conclusion: This study shows that patients with β-thalassemia treated with luspatercept saw a substantial reduction in transfusion burden, in both the frequency of blood transfusion and units of blood used. As those who remained on luspatercept longer, through 12 months, saw an increased reduction in transfusion burden from baseline, these findings suggest the clinical and real-world benefit of longer-term luspatercept treatment.

Efficacy and Safety of Luspatercept in Patients Enrolled in the BELIEVE Trial: Data from the Phase 3b Long-Term Rollover Study

Background: Ineffective erythropoiesis and anemia are pathognomonic features of β-thalassemia, leading to red blood cell (RBC) transfusion dependence in patients with more severe genotypes and consequently increased morbidity and mortality. The phase 3 BELIEVE study showed that luspatercept reduces transfusion burden in transfusion-dependent patients with a manageable safety profile (Cappellini MD, et al. HemaSphere 2022;6[S3]:171-172; Viprakasit V, et al. HemaSphere 2022;6[S3]:2664-2665). Patients who continued to benefit from luspatercept at completion of the BELIEVE study or who needed to complete post-treatment follow-up could roll over to the phase 3b long-term follow-up study (LTFU; NCT04064060) to continue receiving treatment or complete post-treatment follow-up, respectively. Patients receiving luspatercept were monitored for continued efficacy and safety. Methods: The aim of this analysis was to evaluate long-term safety and efficacy of luspatercept in patients who rolled over to the LTFU study. This analysis included patients randomized to luspatercept during BELIEVE (luspatercept group) and those randomized to placebo who crossed over to receive luspatercept after unblinding (crossover group). Response was defined as ≥ 33% reduction from baseline in RBC transfusion burden during any 12-week interval over the entire treatment period of the combined studies. The data cutoff was Jan 2, 2023. Results: At the closure of the BELIEVE trial, 127/224 (56.7%) patients from the luspatercept group and 67/92 (72.8%) patients from the crossover group had transitioned to the LTFU study with the intention to continue luspatercept. At data cutoff, treatment was ongoing for 138 patients, 90 in the luspatercept group and 48 in the crossover group. Median (range) total treatment duration over the combined studies was 229.1 (1.7-336.1) weeks for the luspatercept group and 221.2 (6.1-230.7) weeks for the crossover group; 98 patients had completed 288 weeks (> 5 years) of treatment at data cutoff, all of whom had been randomized to luspatercept. In the luspatercept group, 180/224 (80.4%) patients had achieved response, continuing the trend showing an increasing proportion of responders with longer duration of treatment observed at previous data cutoffs (Figure A). Response in the crossover group was similar with 71/92 (77.2%) responders. Patients in the luspatercept and crossover groups had median (range) reductions in transfusion burden of −17.75% (−100.0 to 33.3) and −19.05% (−100.0 to 20.8), respectively, from baseline to week 145-192, equating to mean reductions of 6.78 RBC units (SD 7.27; n = 120) and 6.85 RBC units (SD 6.78; n = 50), respectively. Liver iron concentration in the luspatercept group was reduced with long-term treatment at each timepoint compared with the baseline (mean decrease of 2.80 mg/g dry weight [dw] at week 144 from median 8.97 [range, 1.1-31.9] at baseline [n = 24]; mean decrease of 0.45 mg/g dw at week 192 from median 7.75 [1.4-35.5] at baseline [n = 27]; mean decrease of 1.48 mg/g dw at week 240 from median 5.65 [1.0-42.0] at baseline [n = 20]). Mean changes from baseline in overall serum ferritin levels (last 24-week level for each patient prior to their efficacy cutoff) were −376.27 μg/L for luspatercept and +43.09 μg/L for crossover. In the combined studies up to data cutoff, 59.4% of luspatercept patients and 47.8% of crossover patients discontinued treatment. The most frequent reason for treatment discontinuation was the patient's personal decision to withdraw (luspatercept: 23.7% in BELIEVE and 33.5% in the combined studies; crossover: 14.1% in BELIEVE and 28.3% in the combined). Discontinuation due to an adverse event (AE) in the combined studies was similar to experience from BELIEVE (luspatercept: 10.3% BELIEVE and 12.5% combined; crossover: 4.3% BELIEVE and 7.6% combined). One patient (0.4%) discontinued luspatercept and transitioned to a commercially available treatment. The frequency of treatment-emergent AEs in the combined studies was also consistent with previous experience from the BELIEVE trial (Figure B). Summary: These long-term data from the LTFU study show that erythroid responses and safety results in both the luspatercept and crossover groups were consistent with previous clinical experience from the BELIEVE trial. Patients receiving long-term luspatercept treatment experience durable clinical benefit with no new safety concerns.

Incidence of blast phase in myelofibrosis according to anemia severity.

Myelofibrosis (MF) is a clonal malignancy frequently characterized by anemia and in 10%-20% of cases it can evolve into blast phase (BP). Anemia in MF is associated with reduced survival and -in primary MF- also with an increased probability of BP. Conventional treatments for anemia have limited effectiveness in MF. Within a dataset of 1752 MF subjects largely unexposed to ruxolitinib (RUX), BP incidence was 2.5% patients per year (p-y). This rate reached respectively 4.3% and 4.5% p-y in case of patients with common terminology criteria for adverse events (CTCAE) grade 3/4 and grade 2 anemia, respectively, that represented together 32% of the cohort. Among 273 MF cases treated with RUX, BP incidence was 2.89% p-y and it reached 4.86% p-y in subjects who started RUX with CTCAE grade 2 anemia (one third of total). Within patients with red blood cell transfusion-dependency at 6 months of RUX (21% of the exposed), BP rate was 4.2% p-y. Our study highlights a relevant incidence of BP in anemic MF patients, with a similar rate whether treated with or without RUX. These findings will help treating physicians to make decisions on the safety profile of innovative anemia treatments.

IMerge: Results from a phase 3, randomized, double-blind, placebo-controlled study of imetelstat in patients (pts) with heavily transfusion dependent (TD) non-del(5q) lower-risk myelodysplastic syndromes (LR-MDS) relapsed/refractory (R/R) to erythropoiesis stimulating agents (ESA).

7004 Background: Unmet needs remain for red blood cell (RBC) TD pts with LR-MDS R/R or ineligible for ESA. In P2 of the IMerge study (NCT02598661), heavily RBC TD ESA R/R non-del(5q) LR-MDS pts naive to lenalidomide and hypomethylating agents (len/HMA) treated with imetelstat, a telomerase inhibitor, achieved durable and continuous transfusion independence (TI). We report primary data from the P3 study of imetelstat in such pts. Methods: Heavily RBC TD ESA R/R non-del(5q) LR-MDS pts naive to len/HMAs were randomized 2:1 to receive imetelstat 7.5 mg/kg or placebo every 4 wks. Primary endpoint was 8-wk TI; subgroup analyses included IPSS risk, prior transfusion burden and ring sideroblast (RS) status. Secondary endpoints included 24-wk TI, TI duration and hematologic improvement-erythroid (HI-E). Variant allele frequency (VAF) changes were explored. Results: As of Oct 2022, 178 pts were randomized. The primary endpoint was met (Table); 39.8% vs 15.0% of pts receiving imetelstat vs placebo, respectively, achieved 8-wk TI. The rate of 8-wk TI was significantly higher with imetelstat vs placebo across subgroups, including RS negative pts. Median TI duration was significantly longer for imetelstat vs placebo, 51.6 vs 13.3 wks, P < 0.001. Pts receiving imetelstat had significantly higher mean hemoglobin (P < 0.001) and fewer transfusions (P = 0.042) over time than those on placebo. In 3 of 4 genes frequently mutated in MDS, VAF reduction was significantly greater in pts treated with imetelstat than placebo: SF3B1 (P < 0.001), TET2 (P = 0.032), DNMT3A (P = 0.019) and ASXL1 (P = NS). SF3B1 VAF reduction correlated with longer TI duration, P < 0.001. No new safety signals were identified. The most common Grade 3/4 AEs were thrombocytopenia and neutropenia, with similar rates of Grade ≥3 bleeding and infections on imetelstat and placebo. In pts treated with imetelstat, cytopenias were manageable, of short duration, and >80% were reversible to Grade ≤2 within 4 wks. Conclusions: For this LR-MDS pt population, imetelstat demonstrated statistically significant and clinically meaningful efficacy with high 8- and 24-wk TI rates, prolonged TI duration and increased hemoglobin. VAF reduction and its correlation to clinical endpoints support imetelstat’s disease-modifying potential. Safety results were consistent with prior reported experience. Clinical trial information: NCT02598661 . [Table: see text]

A phase 2/3 trial of oral azacitidine (Oral-AZA) in patients (pts) with low- or intermediate-risk myelodysplastic syndromes (MDS).

TPS7083 Background: MDS, a heterogeneous group of clonal myeloid malignancies, are characterized by ineffective hematopoiesis and peripheral blood cytopenias, which can often lead to red blood cell (RBC) transfusion dependence and a risk of progression to acute myeloid leukemia (AML). In early clinical trials, 14- and 21-day (d) dosing regimens of the hypomethylating agent Oral-AZA were well tolerated and induced hematologic improvement (HI) in pts with lower-risk (LR) MDS. In a phase 3 trial, Oral-AZA 300 mg QD for 21d per 28d cycle significantly improved the rate of RBC transfusion independence (TI) and induced durable HI versus placebo (PBO) in patients (pts) with LR-MDS with RBC-transfusion-dependent anemia and thrombocytopenia (Garcia-Manero, et al. J Clin Oncol 2021). Grade 3/4 cytopenias were common in the Oral-AZA arm. Given the substantial clinical benefit of Oral-AZA observed in this setting, a new phase 2/3 trial is ongoing to further evaluate the 14d Oral-AZA regimen in pts with International Prognostic Scoring System Revised (IPSS-R)-defined low or intermediate (int)-risk MDS. Methods: This ongoing, multicenter, randomized, phase 2/3 trial (CA055-026; NCT05469737) will evaluate the safety and efficacy of Oral-AZA in pts with IPSS-R low- or int-risk MDS. Key eligibility criteria include ≥ 18 years, ECOG performance status score ≤ 2, and ≥ 1 cytopenia (anemia, thrombocytopenia, or neutropenia). Pts with an absolute neutrophil count < 0.5 × 109/L within a week of randomization will be excluded. Informed consent will be obtained from all participants. The phase 2 portion will enroll and randomize ~42 pts 1:1 to receive open-label Oral-AZA 200 or 300 mg QD for 14d per 28d cycle, plus best supportive care (BSC), to determine the recommended phase 3 dose (RP3D). The primary endpoints are safety and rate of complete remission (CR) within 6 Tx cycles. The secondary endpoints are overall response rate (ORR), and packed (p) RBC-TI and platelet-TI sustained for 84d in ≤ 6 Tx cycles. ORR includes CR, partial remission (PR), marrow CR, and any HI, per IWG 2006 response criteria. In the phase 3 portion, ~188 additional pts will be enrolled and randomized 1:1 to Oral-AZA at the RP3D or PBO for 14d per 28d cycle, plus BSC. Pts in the PBO arm with stable disease at Tx cycle 6 disease assessment or with documented disease progression after ≥ 3 Tx cycles will have the option to cross over into the Oral-AZA arm. The primary endpoint is CR in ≤ 6 Tx cycles. The key secondary endpoint is 84d pRBC-TI. Other secondary endpoints include those described in the phase 2 portion plus overall survival, event-free survival, time to AML progression, iron parameters, health-related quality of life, healthcare resource utilization, and safety parameters. Pts who benefit from Oral-AZA in phase 2 or 3 may continue to receive Tx in an extension phase. Trial recruitment began in December 2022 and is ongoing. Clinical trial information: NCT05469737 .

Updated efficacy and safety data from the AGILE study in patients with newly diagnosed acute myeloid leukemia treated with ivosidenib + azacitidine compared to placebo + azacitidine.

7012 Background: Ivosidenib (IVO) is a potent oral targeted inhibitor of mutant IDH1. In the AGILE study in patients (pts) with newly diagnosed IDH1-mutated acute myeloid leukemia, IVO plus azacitidine (AZA) significantly improved event-free survival (EFS), overall survival (OS), complete remission (CR), and CR or CR with partial hematologic recovery (CR+CRh) rates v placebo (PBO) plus AZA. As of March 2021, median OS (mOS) was 24 months (IVO+AZA) v 7.9 months (PBO+AZA; HR: 0.44; p=0.0005). Long-term follow-up data are presented. Methods: In the double-blind AGILE study, pts were randomized 1:1 to IVO 500 mg QD + AZA 75 mg/m2 SC or IV for 7 days in 28-day cycles, or PBO+AZA. Long-term follow-up data (June 2022) for OS, blood count recovery, transfusion independence and safety are described here. Results: 148 pts were randomized: 73 to IVO+AZA; 75 to PBO+AZA. Median treatment duration was 10.8 months (IVO+AZA) v 3.2 months (PBO+AZA). Five PBO+AZA pts crossed over to IVO+AZA after March 2021 (Table), and no adjustment was made for crossover in the updated OS analysis. At a median follow-up of 28.6 months, mOS was 29.3 months (95% CI 13.2, not reached) for IVO+AZA v 7.9 months (95% CI 4.1, 11.3) for PBO+AZA (HR 0.42 [0.27, 0.65]; p<0.0001). OS rates were 62.9% and 38.3% at 12 months and 53.1% and 17.4% at 24 months, with IVO+AZA and PBO+AZA, respectively. In the IVO+AZA arm, hemoglobin levels steadily increased from baseline (BL; 88.8 g/L) to cycle 8, and then stabilized; mean platelet count recovered from BL values (72.7 x 109/L) as early as week 8 (171.9 x 109/L) and remained stable; and mean neutrophil counts rapidly increased from BL (0.98 x 109/L) to week 3 (3.99 x 109/L) and week 4 (4.36 x 109/L), and then stabilized to within the normal range. Conversion from BL transfusion dependence (red blood cell and/or platelet transfusion dependence) to post-BL transfusion independence was significantly higher with IVO+AZA than PBO+AZA (53.8% v 17.1%, respectively; p=0.0004). There were fewer neutropenic fever events (27.8% v 33.8%) and infections (34.7% v 51.4%) with IVO+AZA than with PBO+AZA. TEAEs led to discontinuation of IVO+AZA or PBO+AZA in 26.4% and 25.7% of pts, respectively. Conclusions: Updated data on OS (>5 months longer mOS and a greater risk reduction in deaths compared to the initial analysis), transfusion independence, blood count recovery and safety confirms the clinically and statistically robust benefit in favor of IVO+AZA at long-term follow up. Patient disposition. Clinical trial information: NCT03173248 . [Table: see text]

Abstract OT2-10-01: A phase 2, randomized study of magrolimab combination therapy in adult patients with unresectable locally advanced or metastatic triple-negative breast cancer

Abstract Background: Improving outcomes for patients (pts) with triple-negative breast cancer (TNBC) remains a high unmet need. Immune checkpoint inhibitors (ICIs) + chemotherapy (chemo) and single-agent sacituzumab govitecan, a trophoblast cell-surface antigen 2–targeted antibody-drug conjugate coupled to SN38 via a proprietary, hydrolysable linker, are approved in newly diagnosed pts with programmed death-ligand 1 (PD-L1)–positive tumors and pts who received ≥2 prior systemic therapies (≥1 for metastatic disease), respectively. However, additional options are urgently needed, particularly for pts with tumors that do not express PD-L1 and for those with progression on chemo ± ICI. Magrolimab is an antibody blocking CD47, a “don’t eat me” signal overexpressed on cancer cells, including TNBC, inducing tumor phagocytosis by macrophages. Magrolimab has shown preclinical activity and promising clinical efficacy in hematologic and solid tumors. Chemo agents, including taxanes, can enhance prophagocytic signals on tumor cells, leading to the potential for synergistic antitumor activity with magrolimab. This study is evaluating the safety/tolerability and efficacy of magrolimab in combination with nab-paclitaxel/paclitaxel or with sacituzumab govitecan in unresectable locally advanced/metastatic TNBC. Trial Design: This open-label, 2-cohort (C) study consists of safety run-in and phase (ph)2 portions evaluating nab-paclitaxel/paclitaxel (choice) + magrolimab (safety run-in) or ± magrolimab (ph2, randomized 1:1) in pts with untreated, advanced/metastatic TNBC ineligible for ICI (C1) and magrolimab + sacituzumab govitecan (safety run-in and ph2) in pts with advanced TNBC who received 1 prior systemic treatment in the metastatic setting (C2). Stratification factors for C1 are neoadjuvant and/or adjuvant taxane therapy, liver metastases, and nab-paclitaxel vs paclitaxel. In both cohorts, magrolimab will be administered intravenously (IV) in de-escalating doses to establish the recommended ph2 dose (RP2D). Nab-paclitaxel/paclitaxel and sacituzumab govitecan will be administered IV per standard of care. Eligibility Criteria: Eligible pts are ≥18 y with PD-L1–negative, untreated, unresectable locally advanced/metastatic TNBC (C1) or unresectable locally advanced/metastatic TNBC who received 1 prior line of therapy in the advanced setting, including a taxane and an ICI if PD-L1 positive (C2), with measurable disease per RECIST v1.1. Exclusion criteria include active central nervous system disease, red blood cell transfusion dependence, or prior treatment with CD47/signal regulatory protein α–targeting agents for both cohorts. Additional exclusions are disease progression within 6 months of (neo)adjuvant therapy or rapid visceral progression and/or symptomatic disease, for which single-agent chemo would not be appropriate (C1); chronic inflammatory bowel disease and a history of bowel obstruction or gastrointestinal perforation within 6 months of enrollment, prior treatment with topoisomerase I inhibitors or antibody-drug conjugates containing a topoisomerase inhibitor, and receipt of high-dose systemic corticosteroids within 2 weeks of cycle 1 day 1 (C2). Specific Aims: The primary objectives are safety/tolerability and magrolimab RP2D (safety run-in) and efficacy (ph2: C1, progression-free survival [PFS]; C2, objective response rate [ORR]; both by investigator). Secondary objectives include ORR, PFS, and duration of response by investigator and independent central review, overall survival, and magrolimab concentration vs time and antidrug antibodies. Present and Target Accrual: The study is enrolling in the US, Australia, and Hong Kong. Target accrual is 144 pts. Contact Information: ClinicalTrials.gov: NCT04958785. Citation Format: Natalie Rainey, Rohit Joshi, Joanne Win Yang Chiu, Ann Chen, Hao Wang, Jared Odegard, Michael Howland, Sylvia Adams. A phase 2, randomized study of magrolimab combination therapy in adult patients with unresectable locally advanced or metastatic triple-negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT2-10-01.

Luspatercept for Treatment of Lower Risk Myelodysplastic Syndromes: Real World Data Replicates Medalist Study Results and Confirms Activity Among Hypomethylating Agents and Lenalidomide Treated Patients

Introduction: Luspatercept, TGF-B fusion trap protein, is a first in class erythroid maturating agent approved by FDA for treatment of red blood cell transfusion dependent (RBC-TD) lower risk myelodysplastic syndromes (LR-MDS) with ring sideroblasts (RS) based on the MEDALIST clinical trial. Red blood cell transfusion independence (RBC-TI) was observed in 38% of 153 patients (pts) treated with luspatercept compared to 13% of 76 pts in the placebo group. We present to our knowledge first real-world data (RWD) in a large cohort of pts treated at our center with luspatercept for LR-MDS. More importantly, we address impact of prior therapies on response namely hypomethylating agents (HMA) as the original clinical trials excluded HMA treated pts. Methods We identified all pts treated at Moffitt Cancer Center with luspatercept since the FDA approval. Baseline RBC transfusion burden (TB) was defined as: non- transfusion dependent (NTD) (0 units in 8 weeks prior luspatercept), low TB (LTB) (1-5 units /8weeks) and high TB (HTB) (≥ 6 units /8 weeks). A hematological response (HI) was defined as an (i) objective Hgb increase of > 1.5 g/dl in NTD, and (ii) RBC-TI with Hgb increase of 1.5 g/dl, or RBC-TI without Hgb 1.5 g/dl increase, or >50% reduction in RBC transfusion burden among RBC-TD. Results Between February 2020 and December 2021, 114 pts were treated with luspatercept. Table-1 summarizes baseline characteristics in comparison to Medalist trial, the median age was 70 years. Seventy-three pts (67%) had MDS-RS subtype, 91% were intermediate or lower risk MDS by R-IPSS. SF3B1 mutation (MT) was detected in 71% (80/112). The mean Hgb level was 7.90 g/dl and 47% were RBC HTB transfusion dependent. The median serum erythropoietin (epo) level at time of referral was 122 U/L (19% > 500 U/L) (n=77). Majority had prior erythroid stimulating agents (ESA) (89%) with 29% hematological response to prior ESA, 59 pts (53%) had prior HMA therapy, and 42 patients (47%) had prior lenalidomide (len). The overall HI rate to luspatercept was 39.5% (45/114). Table-2 summarizes detailed responses. HI correlated with baseline RBC-TB where 69% (9/13) NTD, 47% (21/47) LTB and 25% HTB (13/53) achieved HI respectively, p=.004. Almost 55% of pts needed dose escalation, 62 pts received 1.33 mg/kg and 63 pts received 1.75 mg among whom 40% (25 pts) demonstrated response to higher doses. Based on RBC-TB, 75% (6/8) NTD patients achieved HI with highest dose escalation, 40% (10/25) LTB pts achieved HI with dose escalation and 30% (9/30) HTB pts achieved response with dose escalation. Among responders, the median duration of response was 15.6 months (2.6-27.3). As off last follow up, 56 pts (49%) discontinued treatment. Reason of discontinuation was lack of response in 47 pts, loss of response in 4 patients and adverse events in 5 pts (58 pts are still on therapy). The most common captured adverse events were fatigue (n=8), GI (n=4), shortness of breath and arthralgia (1 each). The response rates were higher among SF3B1 MT pts compared to wild type, 48% (34/80) compared to 16% (5/32), p=.002. The response rate among pts with RS subtypes versus non-RS were 49% versus 28% respectively, p=.05. Among 14 pts with MDS/MPN-RS-T the HI rate was 79%. HI for pts with serum epo < 500 U/L, was 48% (30/62) compared to 13% 2/15) for those with serum epo > 500, p=.01. Majority of pts with high serum epo level were RBC HTB at baseline 67% (10/15). The HI rate was 30% (18/60) after HMA failure compared to 50% (27/54) in HMA naïve pts, (p=.03). More pts post HMA failure were RBC-HTB 62% compared to 30% in HMA naïve. The luspatercept HI among RBC-LTB HMA failure pts was 39% compared to 54% in HMA naïve LTB, however, it was 24% among HTB HMA failure compared to 25% among HMA naïve HTB. The HI rate was 33% (15/46) for len failure pts compared to 43% (29/67) naïve patients, (p=.3). In multivariable analysis both SF3B1 mutation status and baseline RBC TB independently correlated with luspatercept response but not HMA failure. Conclusions Our RWD confirms luspatercept clinical benefit and safety profile observed in the MEDALIST trial. Responses are dose dependent with 1/3 of patients who were dose escalated responding. Low baseline RBC-TB dependency and SF3B1 MT correlated with higher response rates. Luspatercept retained activity after HMA or lenalidomide failure however a trend of lower responses observed correlated with RBC-HTB among those patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Cryopreserved versus fresh peripheral blood allogeneic stem cell transplantation outcomes in patients receiving post-transplant cyclophosphamide for graft-versus-host prophylaxis during the COVID-19 pandemic: a single center experience.

Cryopreservation of grafts is not common practice in allogeneic hematopoietic stem cell transplant (HSCT) recipients. However, our center had to use cryopreserved cells for allogeneic HSCT during the COVID-19 pandemic to avoid delays in transplantation due to uncertainty regarding patient and donor exposures. We retrospectively evaluated post-transplant engraftment and survival outcomes of adult patients who received cryopreserved versus fresh allografts during the COVID-19 pandemic. Fifty-five patients with hematologic malignancies received either cryopreserved (n = 34) or fresh (n = 21) allogeneic HSCT using peripheral blood stem cells between January 2020 and December 2020. At a median follow-up time of 15months, cryopreserved allograft recipients had significantly lower overall survival (OS) (p = 0.02). They also experienced significantly delayed neutrophil (p = 0.01) and platelet engraftments (p < 0.0001), as well as higher red blood cell transfusion-dependence after day + 60 (67.6% vs. 28.6%; p = 0.01). Significantly more cryopreserved allograft recipients received donor lymphocyte infusion than fresh allograft recipients (35.3% vs. 4.8%, p = 0.01). Neither relapse-free survival nor non-relapse mortality differed significantly between the two groups. Cryopreservation of allografts in combination with post-transplant cyclophosphamide may negatively affect engraftment and OS outcomes in HSCT recipients.

Luspatercept (RAP-536) modulates oxidative stress without affecting mutation burden in myelodysplastic syndromes.

In low-risk myelodysplastic syndrome (LR-MDS), erythropoietin (EPO) is widely used for the treatment of chronic anemia. However, initial response to EPO has time-limited effects. Luspatercept reduces red blood cell transfusion dependence in LR-MDS patients. Here, we investigated the molecular action of luspatercept (RAP-536) in an in vitro model of erythroid differentiation of MDS, and also in a in vivo PDX murine model with primary samples of MDS patients carrying or not SF3B1 mutation. In our in vitro model, RAP-536 promotes erythroid proliferation by increasing the number of cycling cells without any impact on apoptosis rates. RAP-536 promoted late erythroid precursor maturation while decreasing intracellular reactive oxygen species level. RNA sequencing of erythroid progenitors obtained under RAP-536 treatment showed an enrichment of genes implicated in positive regulation of response to oxidative stress and erythroid differentiation. In our PDX model, RAP-536 induces a higher hemoglobin level. RAP-536 did not modify variant allele frequencies in vitro and did not have any effect against leukemic burden in our PDX model. These results suggest that RAP-536 promotes in vivo and in vitro erythroid cell differentiation by decreasing ROS level without any remarkable impact on iron homeostasis and on mutated allele burden.

A natural history of lower-risk myelodysplastic syndromes with ring sideroblasts: an analysis of the MDS-CAN registry

Patients with lower-risk (LR) myelodysplastic syndromes (MDS) with ring sideroblasts (RS) have better prognosis than those without RS, but how they fare over time is not fully understood. This study’s objective was to assess the natural history of LR MDS with RS ≥5% using MDS-CAN registry individual data. Kaplan–Meier estimates and generalized linear mixed models were used to describe time-to-event outcomes and continuous outcomes, respectively. One hundred and thirty-eight patients were enrolled; median times from diagnosis to enrollment and follow-up were 6.6 and 39.6 months, respectively. Within 5 years of enrollment, 65% of patients had ≥1 red blood cell transfusion dependence episode. Within 5 years of diagnosis, 59% developed iron overload, 38% received iron chelation therapy, 14% progressed to acute myeloid leukemia, and 42% died. Patients exhibited inferior health-related quality of life trends. These first real-world data in LR MDS-RS in Canada indicate a high level of morbidity and mortality over a 5-year period. Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT02537990

Protocol for a Nested, Retrospective Study of the Australian Placental Transfusion Study Cohort.

BackgroundNeonates, particularly if born preterm or with congenital anomalies, are among the pediatric patients most likely to need blood transfusion. However, they are also particularly vulnerable to adverse consequences of blood transfusion. Aiming to clamp the umbilical cord for at least a minute after birth is a simple safe procedure that is being increasingly adopted worldwide, although may be associated with increased rates of polycythemia and jaundice. It may also reduce the proportion of preterm babies who need a blood transfusion. The mechanisms for this are not fully understood. Potential mechanisms could include an increased volume of blood transfusion from the placenta to the baby after birth, and an overall reduction in the severity of illness in the first weeks after birth, which could lead to fewer blood tests and greater tolerance of anemia, or enhanced erythropoiesis.ObjectivesTo investigate the mechanism behind the reduced need for blood transfusions after deferral of cord clamping.MethodologyThis protocol outlines the methods and data analysis plan for a study using nested retrospective data from a large randomized trial combined with additional data collected from patient medical and pathology records. The additional data items to be collected all relate to the receipt of transfusion and the factors that affect the risk for transfusion in preterm babies. The analysis will include all randomized babies from Australia and New Zealand for whom data are available. Causal mediation analysis is planned to estimate the effects of mediators on the relationship between the timing of cord clamping and the need for blood transfusion. The analysis is designed to discern whether initial severity of illness or the magnitude of placental transfusion mediates red blood cell transfusion dependence.Anticipated outcomes and disseminationWe expect the study will identify potential strategies for reducing blood transfusions and associated negative outcomes in preterm infants. This will be relevant to researchers, clinicians, and parents. The results will be disseminated through publications, presentations, and inclusion in evidence-based guidelines.