In February 2008, Acceleron entered into a worldwide strategic collaboration with Celgene Corporation for the joint development and commercialization of sotatercept (ACE-011).

In August, 2011, Acceleron and Celgene expanded the collaboration to include a second product, luspatercept (ACE-536).

In total, Acceleron has received $75 million from Celgene in upfront payments. Acceleron and Celgene will collaborate to develop both sotatercept and luspatercept and potentially other products for treating anemia across a wide range of indications. Acceleron is eligible to receive up to $367 million in milestone payments for the sotatercept program and up to $200M for the luspatercept program.

As of January 1, 2013, Celgene became responsible for paying 100% of worldwide development costs for both programs.  Celgene will be responsible for all commercialization costs worldwide.  Acceleron and Celgene will co-promote the products in North America.  Acceleron will receive royalty payments on worldwide product sales.