Pfizer Sues Teva, Slayback to Block Copies of Two Xeljanz Doses

Pfizer Inc. filed lawsuits alleging two generic versions of Xeljanz proposed by Teva Pharmaceuticals USA Inc. and Slayback Pharma LLC each infringe a different patent for the blockbuster arthritis drug.

In a complaint filed against Slayback in the U.S. District Court for the District of Delaware, Pfizer alleges Slayback’s copycat of Xeljanz’s oral solution infringes a patent that expires in December 2025. Another complaint, also filed in Wilmington, Del., targets Teva’s copycat of Xeljanz XR’s 22-milligram tablet for alleged infringement of a different patent that expires in March 2034.

In each complaint, both of which were filed Feb. 11, ...