Regeneron has sued Sanofi, its partner in the commercialisation of the blockbuster eczema drug Dupixent® (dupilumab), in the US District Court for the Southern District of New York alleging that Sanofi is in breach of its commercialisation agreement. The issues relate to contracts Sanofi negotiates with intermediaries between drug-makers, pharmacies, and insurance companies. Regeneron alleges that Sanofi has not allowed it access to the relevant contracts to verify compliance with its profit-sharing arrangement.
Regeneron and Sanofi have previously been on the same side in dupilumab patent proceedings against Amgen and Immunex. In that matter, the PTAB denied the institution of a review, deciding that the petitioners had not established a reasonable likelihood that they would prevail in showing the unpatentability of the patent.