Celgene Corporation (NASDAQ:CELG) and Acceleron Pharma Inc. (NASDAQ:XLRN) today announced interim data from two studies of candidates from the companies’ joint development program in beta-thalassemia. The data presented at the 19
European Hematology Association (EHA) annual congress show activity for two programs, sotatercept and ACE-536, in patients with both transfusion dependent and non-transfusion dependent beta-thalassemia. There is currently no drug approved to treat beta-thalassemia. Both sotatercept and ACE-536 have been granted orphan drug designation for beta-thalassemia by the United States Food and Drug Administration (FDA).
In the first study, which was highlighted as part of the EHA press briefing on June 13, sotatercept, a novel activin type IIA receptor fusion protein, was evaluated in transfusion-dependent (TD) and non-transfusion-dependent (NTD) beta-thalassemia patients.
A total of 32 patients were treated in this dose-finding study in which sotatercept was administered subcutaneously once every 3 weeks at doses of 0.1 (n=8), 0.3 (n=9), 0.5 (n=8), or 0.75 (n=7) mg/kg. Of these patients, 22 were non-transfusion dependent and 10 were transfusion dependent.
The mean baseline hemoglobin level for the NTD patients was 8.7 g/dL (range 6.1-10.7), 8.3 g/dL (range 6.0-9.5), 8.2 g/dL (range 6.4-9.3) and 8.8 g/dL (range 7.9-9.6) in the 0.1, 0.3, 0.5 and 0.75 mg/kg groups, respectively. Among these patients, there was a dose-dependent increase in hemoglobin.
- The proportion of patients achieving a maximum hemoglobin increase of ≥ 1.0 g/dL above baseline was 0%, 67%, 83% and 100% in the 0.1, 0.3, 0.5, and 0.75 mg/kg dose groups, respectively.
- The proportion of patients achieving a maximum hemoglobin increase of ≥ 2.0 g/dL above baseline was 0%, 0%, 33% and 50% in the 0.1, 0.3, 0.5 and 0.75 mg/kg dose groups, respectively.
In TD patients, there were dose dependent reductions in transfusion burden.
- The proportion of patients achieving ≥ 20% reduction in transfusion burden was 0%, 33%, 50% and 67% in the 0.1, 0.3, 0.5, and 0.75 mg/kg dose groups, respectively.
- The proportion of patients achieving ≥ 50% reduction in transfusion burden was 0%, 0%, 0% and 33% in the 0.1, 0.3, 0.5, and 0.75 mg/kg dose groups, respectively.
Of these 32 patients, 25 remain on treatment, with the longest duration of treatment > 78 weeks (patient still on study). Three treatment-related adverse events of grade 2 or higher occurred, leading to treatment discontinuation. In the 0.1 mg/kg group, one TD patient experienced worsening grade 3 bone pain and one NTD patient experienced grade 2 phlebitis. In the 0.5 mg/kg group, one patient with a history of ventricular extrasystoles experienced a grade 3 adverse event of ventricular extrasystoles.