Keros Therapeutics presents clinical data from elritercept program

Keros Therapeutics presented additional data from its two ongoing Phase 2 clinical trials of elritercept, one in patients with very low-, low-, or intermediate-risk myelodysplastic syndromes and one in patients with myelofibrosis, at the 29th Annual Hybrid Congress of the European Hematology Association, held in person in Madrid, Spain and virtually from June 13 through 16, 2024. In addition, Keros presented preclinical data showing that, in an animal model of MF, a research form of elritercept promoted erythropoiesis, mitigated anemia associated with MF, improved anemia associated with ruxolitinib therapy and improved muscle mass and function. Durable Clinical Benefit with Elritercept Treatment: Findings From an Ongoing Phase 2 Trial in Participants with Lower-Risk MDS: This ongoing, open-label, two-part, Phase 2 clinical trial is evaluating elritercept in patients with very low-, low-, or intermediate-risk MDS. As of April 3, 2024, 87 patients had received at least one dose of elritercept at the recommended Part 2 dose. Of these patients in the safety population, 81 had completed at least 24 weeks of treatment or discontinued as of the data cut-off date. Data for hematological response and markers of hematopoiesis were presented from exploratory analyses of these mITT24 patients. All data presented from this trial is as of the data cut-off date. Of the 87 patients in the safety population, 57.5% were high transfusion burden while 25.3% were low transfusion burden and 17.2% were non-transfused. Elritercept was observed to be generally well-tolerated in the safety population. There were three cases of fatal treatment-emergent adverse events in the trial that were all deemed unrelated to treatment. The most commonly reported TEAEs were diarrhea, fatigue, dyspnea, dizziness, COVID-19, nausea and anemia. No patients had progressed to acute myeloid leukemia. 55.6% of the mITT24 patients achieved an overall erythroid response over the first 24 weeks of treatment, which is defined as meeting either modified International Working Group 2006 Hematological improvement-erythroid or transfusion independence for at least eight weeks in transfusion-dependent patients who required greater than or equal to 2 red blood cell units transfused at baseline. Additional data from the mITT24 patients include: 41.3% of the TI-evaluable patients achieved TI for at least eight weeks over the first 24 weeks of treatment. 16 of those 26 patients achieved TI for at least 24 weeks over the first 48 weeks of treatment. Of the patients with HTB, 34.8% achieved TI for at least eight weeks during the first 24 weeks of treatment. Eight of those 16 patients achieved TI for at least 24 weeks over the first 48 weeks of treatment. Of the TI-evaluable patients with baseline erythropoietin level less than 500 U/L, 50.0% achieved TI for at least eight weeks over the first 24 weeks of treatment. Of the TI-evaluable patients with baseline erythropoietin level less than 500 U/L and HTB, 42.9% achieved TI for at least eight weeks over the first 24 weeks of treatment. The median duration of transfusion independence was not met as of the data-cutoff date. 61.5% of patients with a TI response had ongoing TI as of the data-cutoff. Of the patients that achieved TI, 42.3% had responses of greater than one year, with all ongoing as of the data cut-off date. The FACIT-Fatigue scale, a measure of self-reported fatigue and its impact upon daily activities and function, was utilized to assess health-related quality of life in 62 of the mITT24 patients who were TI-evaluable and with baseline FACIT-Fatigue assessment. A difference of three in the FACIT-Fatigue scale is considered a minimally clinically important difference. In this group, patients who achieved TI had durable and clinically meaningful improvements in self-reported fatigue. Patients achieving TI of 24 weeks or longer had a mean change from baseline of 6.6 versus patients who did not achieve TI of at least 24 weeks, who reported a mean change from baseline of -2.7, for a mean difference of 9.4. The majority of patients enrolled in this ongoing trial had HTB and/or multi-lineage dysplasia, indicating a difficult-to-treat trial population. Durable TI responses continue to be observed in a broad range of patients with lower-risk MDS, including in those with HTB, which support the potential for elritercept to ameliorate ineffective hematopoiesis across multiple lineages in patients with MDS. Patients who achieved TI showed clinically meaningful improvements in FACIT-Fatigue scores, indicating that elritercept may improve quality of life in patients with lower-risk MDS.