Imago BioSciences presents data from Phase 2 study of bomedemstat in ET

Imago BioSciences presented data from its ongoing global Phase 2 clinical study evaluating bomedemstat in patients with essential thrombocythemia who have failed at least one standard of care. The data were presented in an oral presentation session during the 64th American Society of Hematology Annual Meeting and Exposition taking place 10-13 December 2022. A Phase 2 data set with a cut-off date of 29 April 2022 was previously presented at the 30th European Hematology Association Annual Meeting and congress in June 2022. Updated Highlights: Of the 62 Patients treated with bomedemstat for more than 24 weeks: 100% achieved platelet count reduction to less than or equal to 400 x 109/L. 95% achieved platelet count reduction to less than or equal to 400 x 109/L in the absence of thromboembolic events. 89% of the 28 patients treated with bomedemstat for at least 48 weeks achieved a durable response by week 48, defined as platelet count of less than or equal to 400 x 109/L for greater than or equal to 12 weeks. Of the 12 patients with baseline Total Symptom Scores greater than 20:75% showed a decrease in TSS. 67% showed improvements greater than or equal to 10 points.Platelet response rate was 100% across all genotypes identified in the study. Further, 67% patients demonstrated a net decrease in mutation allele frequencies including both CALR and JAK2. 100% patients with baseline loss of heterozygosity and follow-up samples demonstrated a reduction in homozygous mutant granulocytes and mutant allele frequencies.Bomedemstat was generally well-tolerated with no safety signals identified per the Safety Advisory Board.The most common adverse events regardless of causality were dysgeusia, constipation, thrombocytopenia, arthralgia, fatigue, contusion and diarrhea. There were 38 reported serious adverse events, 7 of which were deemed drug-related by the investigator in 5% of patients. 20 patients have discontinued treatment, with 10 due to AEs, 1 death from aspiration pneumonia unrelated to bomedemstat, 7 due to withdrawal of consent, 1 due to investigator decision, and 1 due to disease progression.