Cabaret Biotech filed suit against Gilead and its Kite Pharma subsidiary alleging that Yescarta its CAR-T immunotherapy for non-Hodgkin’s lymphoma, infringed on its patent (7,741,465) targeting chimeric receptor genes.

The lawsuit in the U.S. District Court for Delaware alleges that in December 2013, while Kite was developing Yescarta (axicabtagene ciloleucel) — formerly known as KTE-C19 — it entered into a licensing agreement with Cabaret for its patent, making Kite the exclusive licensee. Under the agreement, Kite agreed to pay annual licensing fees and royalties based on the success of the licensed drugs, which it paid until October 2018.

Following its $11.9 billion acquisition of Kite, Gilead informed Cabaret that it had concerns with the licensing deal — and just last month threatened to sue Cabaret to invalidate its patent.