In 2015, Sanofi and Regeneron formed an alliance ( to discover, develop and commercialize new antibody cancer treatments. At the time, Sanofi paid Regeneron $640 million upfront and committed to spending $750 million to take programs up to clinical proof of concept. The collaboration was intended to last through mid-2020.

However, the antibody development collaboration between the two companies has ended. Sanofi indicated that the restructuring will provide “increased flexibility to advance its early-stage immuno-oncology pipeline independently,” with the money saved on the deal freed up for investment on internal projects.

To make its exit, Sanofi will pay Regeneron $462 million to cover its share of drug discovery costs from the last quarter, a termination fee and development support for two clinical-stage assets, for which it is retaining the right to opt into. The two bispecific programs include BCMAxCD3 and MUC16xCD3. Regeneron will spend up to $70 million to develop the BCMAxCD3 drug for multiple myeloma and as much as $50 million on the MUC16xCD3 bispecific for mucin-16–expressing cancers.  The terms for the BCMAxCD3 program are similar to those in the original 2015 deal. Regeneron will also retain full rights to the other candidates developed through the collaboration.