Bivatuzumab mertansine consists of the Boehringer Ingelheim anti-CD44v6 antibody, bivatuzumab, and ImmunoGen’s DM1 cytotoxic agent, mertansine. Development of bivatuzumab mertansine was discontinued due to the occurrence of skin toxicity in phase I clinical trials in patients with advanced carcinoma.
Although Boehringer Ingelheim has decided to discontinue this program, the company is retaining its right to use ImmunoGen technology for a different oncology target.
CD44v6 is expressed on various carcinomas, including squamous cell carcinomas and a proportion of adenocarcinomas. Published data indicate that the CD44v6 antigen is also expressed on normal proliferating epidermal cells.
In 2001, Boehringer Ingelheim licensed the right to use ImmunoGen’s DM1 tumor-activated prodrug (TAP) technology. Under this agreement, Boehringer Ingelheim can use ImmunoGen’s DM1 to create an anticancer compound to a different antigen target in the event of choosing to discontinue development of an anti-CD44v6 TAP compound at an early stage.
“While we are disappointed that bivatuzumab mertansine will no longer be developed, we recognize that only a fraction of the potential new therapeutics that begin clinical testing ever make it to market,” said Dr Mitchel Sayare, ImmunoGen’s chairman and CEO.