Exelixis, Inc. and GamaMabs Pharma have entered an agreement under which Exelixis will acquire all rights to GamaMabs’ AMHR2 antibody technology. Exelixis will pay GamaMabs $5 million upfront and will make additional payments upon closing and achieving certain milestones. Exelixis will control 100% of GamaMabs’ AMHR2 franchise technology including all assets pertaining to GamaMabs’ monoclonal antibody drug product murlentamab (GM-102).

“GamaMabs has generated a compelling body of preclinical data supporting the potential of AMHR2 as a target for novel oncology therapies and demonstrated the safety of an anti-AMHR2 monoclonal antibody in human clinical trials,” said Peter Lamb, Ph.D., Executive Vice President, Scientific Strategy and Chief Scientific Officer of Exelixis. “Based on these data, we believe that applying our ADC capabilities to GamaMabs’ panel of antibodies against AMHR2 could yield a promising new addition to our biotherapeutics portfolio.”

While AMHR2 expression is normally restricted to ovary, testis and adrenal tissues, it is also expressed in ovarian, endometrial, renal, liver, colon and lung tumors. Murlentamab, a monoclonal antibody targeting AMHR2, was well tolerated when administered on its own in Phase 1 and 2 studies, with no dose-limiting toxicities observed. In early 2021, GamaMabs discontinued development of murlentamab given the modest single-agent efficacy observed in these trials. Although it does not have plans to move murlentamab forward, Exelixis is encouraged by the potential of the AMHR2 target as it pursues the further discovery and development of novel biologics.