A Phase 3 clinical trial evaluating luspatercept in adults with beta-thalassemia-associated anemia met the primary endpoint. The results were presented at the American Society of Hematology (ASH) in San Diego.

The phase 3 trial was a randomized, double-blind, multi-center clinical study (called BELIEVE). Luspatercept achieved a highly statistically significant improvement in the primary endpoint of erythroid response, which was defined as at least a 33 percent reduction from baseline in red blood cell (RBC) transfusion burden with a reduction of at least 2 units during the protocol-defined period of 12 consecutive weeks, from week 13 to week 24, compared to placebo.

BELIEVE evaluated the efficacy and safety of luspatercept plus best supportive care versus placebo plus best supportive care in adults with transfusion-dependent beta-thalassemia.

In addition to achieving the primary endpoint of the study, luspatercept also met all key secondary endpoints of demonstrating statistically significant improvements in RBC transfusion burden from baseline of at least a 33 percent reduction during the period from week 37 to week 48, at least a 50 percent reduction during the period from week 13 to week 24, at least a 50 percent reduction during the period from week 37 to week 48, and a mean change in transfusion burden from week 13 to week 24.

Adverse events observed in the study were generally consistent with previously reported data.

“For decades, the management of beta-thalassemia in adults has been limited to transfusions and iron chelation. Reduction of transfusion burden represents an important step forward for patients with this rare and debilitating blood disease,” said Jay Backstrom, M.D., Chief Medical Officer for Celgene. “We thank the patients, as well as their families and physicians, for their participation in the BELIEVE study.”

“The BELIEVE study marks the second positive phase III study for luspatercept and underscores the potential of this erythroid maturation agent to impact a range of diseases associated with chronic anemia,” said Habib Dable, President and Chief Executive Officer of Acceleron. “We continue to explore luspatercept across our broader development programs, including non-transfusion dependent beta-thalassemia in the ongoing BEYOND study.”

The companies also recently announced that luspatercept met the primary and key secondary endpoints in the MEDALIST study, a phase III, randomized, double-blind, multi-center clinical trial evaluating the efficacy and safety of luspatercept versus placebo in patients with IPSS-R very low, low or intermediate risk myelodysplastic syndromes (MDS) with chronic anemia and refractory to, intolerant of, or ineligible for treatment with an erythropoietin-stimulating agent (ESA), ring sideroblast-positive and require frequent RBC transfusions.

Data from BELIEVE and MEDALIST will be submitted to a future medical meeting in 2018. The companies plan to submit regulatory applications for luspatercept in the United States and Europe in the first half of 2019.

Luspatercept is currently not approved for any indication