Eli Lilly has notified Rigel Pharmaceuticals of its decision to terminate the exclusive license and strategic collaboration agreement for the RIPK1 inhibitor ocadusertib (R552), effective 15 June 2026. The agreement, signed in February 2021, granted Lilly global rights to develop and commercialise the candidate, a selective allosteric inhibitor of RIPK1 for non-central nervous system diseases. The deal originally included an upfront payment of USD 125 million and potential milestones of up to USD 835 million, plus tiered royalties.

Lilly recently presented preclinical and Phase I data for ocadusertib in March 2026. The Phase I study in healthy volunteers showed the drug achieved over 90% target engagement and was well-tolerated. Despite the positive early data, Lilly has elected to discontinue the program. The termination underscores the high attrition rate in drug development, even for candidates that show initial promise. Rigel will regain all rights to the asset.

According to PharmCube's NextBiopharm® database, this brings the amount Lilly has invested in terminated agreements to USD 756 million in reported upfront payments alone. Click here to request a free trial for NextBiopharm®.