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Studies Presented at 19th European Hematology Association Annual Congress Evaluate Activin Receptor Ligand Trap Programs in Beta-Thalassemia

July 2, 2014



By a News Reporter-Staff News Editor at Biotech Week -- Celgene Corporation (NASDAQ:CELG) and Acceleron Pharma Inc. (NASDAQ:XLRN) announced interim data from two studies of candidates from the companies' joint development program in beta-thalassemia. The data presented at the 19th 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). Sotatercept 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 (see also Pharmaceutical Companies).

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.

"Activin receptor ligand traps like sotatercept could potentially offer an important new treatment option for patients with beta-thalassemia," said Prof. John Porter of the Research Department of Haematology, University College London. "Therapies that can increase hemoglobin levels and relieve red-blood cell transfusion burden have significant potential as current options are very limited." ACE-536 A second study evaluated ACE-536, a novel modified activin type IIB receptor fusion protein, in transfusion-dependent (TD) and non-transfusion dependent (NTD) beta-thalassemia patients.

A total of 24 patients were treated with ACE-536 administered subcutaneously once every 3 weeks at doses of 0.2 (n=6), 0.4 (n=6), 0.6 (n=6), or 0.8 (n=6) mg/kg. Patients were eligible to receive up to 5 doses over the 13 weeks of treatment, and then followed for 8 weeks after their last dose. Of these patients, 20 were non-transfusion dependent and 4 were transfusion dependent.

The mean baseline hemoglobin level for the NTD patients was 8.4 g/dL, 8.4 g/dL, 7.8 g/dL and 8.0 g/dL in the 0.2, 0.4, 0.6 and 0.8 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 33%, 67%, 100% and 67% in the 0.2, 0.4, 0.6, and 0.8 mg/kg dose groups, respectively.

The proportion of patients achieving a maximum hemoglobin increase of = 2.0 g/dL above baseline was 0%, 0%, 20% and 33% in the 0.2, 0.4, 0.6 and 0.8 mg/kg dose groups, respectively.

For the four TD patients (one patient received 0.6 mg/kg and 3 patients received 0.8 mg/kg), all demonstrated reductions in transfusion burden (-78.5%, -66.7%, -66.7% and -69.8%). Furthermore, all four patients demonstrated reductions in serum ferritin levels (-39.7%, -27.5%, -59.5% and -42.7%), a marker of iron overload.

No related serious adverse events have been reported to date in this ongoing study. One patient discontinued early due to a related AE (ankle pain in the 0.8 mg/kg group).

Keywords for this news article include: Hemolytic, Cardiology, Blood Proteins, beta-Thalassemia, Hemoglobinopathies, Celgene Corporation, Hematologic Diseases, Biotechnology Companies, Biopharmaceutical Companies, Hemic and Lymphatic Diseases.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


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Source: Biotech Week


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