Merck challenges insulin patents, but Sanofi claims infringement 

French pharmaceutical company Sanofi is suing US-based Merck & Co to defend its US patent rights on diabetes blockbuster Lantus (insulin glargine).

The suit is in response to Merck filing for regulatory approval of a biosimilar insulin glargine in August. Merck’s application directly challenges the validity of 10 Sanofi patents surrounding Lantus. As such, Merck asserts that it is not infringing the patents, because it believes them to be invalid.

Almost exactly a year ago, Sanofi settled patent litigation with Eli Lilly and granted Lilly a license to market its insulin glargine biosimilar, Basaglar, in exchange for delaying the US launch to December 2016. In Europe, the biosimilar has been marketed by Lilly’s partner, Boehringer Ingelheim, since September 2015.