Celgene Corporation And Acceleron Pharma Announce Results Of The Phase 3 BELIEVE Trial Evaluating Luspatercept In Adult Patients With Beta-Thalassemia At ASH 2018

- Dec 17, 2018-

December 01, 2018 Celgene Corporation (NASDAQ: CELG) and Acceleron Pharma Inc. (NASDAQ: XLRN) today announced results from a pivotal, phase 3 trial (BELIEVE) evaluating the safety and efficacy of luspatercept for the treatment of adults with beta-thalassemia-associated anemia who require regular red blood cell (RBC) transfusions. The data were presented by Maria Domenica Cappellini, M.D. in an oral session of the 60th American Society of Hematology (ASH) Annual Meeting and Exposition in San Diego, CA (Abstract #163).

“Currently, the standard of care to help patients with beta-thalassemia manage their anemia is regular, lifelong red blood cell transfusions, which over time can result in iron overload and life-threatening co-morbidities,” said Professor Cappellini, M.D., Professor of Medicine, University of Milan - Fondazione IRCCS. “These findings from the BELIEVE study are exciting because they suggest that luspatercept may help patients reduce their dependence on red blood cell transfusions.”

BELIEVE met the primary endpoint of erythroid response, defined as a ≥33% reduction in RBC transfusion burden (with a reduction of ≥ 2 units of RBC) during weeks 13–24 compared to the baseline 12-week interval prior to randomization. The study also included secondary endpoints that evaluated the impact of treatment on RBC transfusion burden. Mean change in transfusion burden from baseline to weeks 13-24 (luspatercept vs. placebo) was -1.35 RBC units.

RBC Transfusion Burden Reduction of ≥ 33% Response Rates1

Response Time Interval Luspatercept Placebo P-value

Weeks 13-24 21.4% (48/224) 4.5% (5/112) < 0.0001

Weeks 37-48 19.6% (44/224) 3.6% (4/112) < 0.0001

Any 12 weeks during the entire treatment period 70.5% (158/224) 29.5% (33/112) < 0.0001

Any 24 weeks during the entire treatment period 41.1% (92/224) 2.7% (3/112) < 0.0001


 RBC Transfusion Burden Reduction of ≥ 50% Response Rates1

Response Time Interval Luspatercept Placebo P-value

Weeks 13-24 7.6% (17/224) 1.8% (2/112) 0.0303

Weeks 37-48 10.3% (23/224) 0.9% (1/112) 0.0017

Any 12 weeks during the entire treatment period 40.2% (90/224) 6.3% (7/112) < 0.0001

Any 24 weeks during the entire treatment period 16.5% (37/224) 0.9% (1/112) < 0.0001


1RBC transfusion burden reduction response rates are calculated versus baseline (i.e., the 12 weeks prior to randomization)

BELIEVE Safety Summary (Safety Population)

Grade 3 or higher treatment-emergent adverse events (TEAEs) were reported in 29.1% (65/223) of patients receiving luspatercept and 15.6% (17/109) of patients receiving placebo. Serious adverse events were reported in 15.2% (34/223) of patients receiving luspatercept and 5.5% (6/109) of patients receiving placebo. A TEAE of acute cholecystitis resulted in death in one placebo-treated patient (0.9%). No luspatercept-treated patients died due to TEAEs.

Grade 3 or 4 TEAEs in at least 1% of patients in either arm


N= 223


N= 109

Anemia 3.1% 0.0%

Increased liver iron concentration 2.7% 0.9%

Hyperuricemia 2.7% 0.0%

Hypertension 1.8% 0.0%

Syncope 1.8% 0.0%

Back pain 1.3% 0.9%

Bone pain 1.3% 0.0%

Blood uric acid increased 1.3% 0.0%

Increased aspartate aminotransferase 1.3% 0.0%

Increase alanine aminotransferase 0.9% 2.8%

Thromboembolic events* 0.9% 0.0%


*All grades of thromboembolic events, including DVT, PE, portal vein thrombosis, ischemic stroke, thrombophlebitis, and superficial phlebitis were reported in 8 of 223 (3.6%) luspatercept-treated versus 1 of 109 (0.9%) placebo-treated patients

“The BELIEVE results demonstrate the potential of luspatercept to help adults living with beta-thalassemia better manage their anemia and reduce their transfusion burden,” said Alise Reicin, M.D., President, Global Clinical Development for Celgene. “These results further our understanding of the luspatercept clinical profile, which will continue to inform our plans to advance this promising investigational therapy.”

“These outcomes of the BELIEVE trial increase our confidence in the potential of luspatercept to become an important new treatment option for patients suffering from beta-thalassemia,” said Habib Dable, President and Chief Executive Officer of Acceleron. “Our focus now is to work diligently with health authorities to help ensure that this underserved patient population can gain access to luspatercept as quickly as possible.”

Luspatercept is not approved in any region for any indication. The companies are planning regulatory application submissions of luspatercept in the United States and Europe in the first half of 2019.