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Biotech Battles GSK Over Cancer Drug Royalties
9 Jan
Summary
- AnaptysBio filed a partial motion to dismiss GSK's claim.
- The dispute concerns royalties from the cancer drug Jemperli.
- A trial is scheduled for July 14-17, 2026.
AnaptysBio announced on January 8, 2026, that it submitted a partial motion to dismiss a claim from GSK's oncology division. This move intensifies a legal conflict concerning royalty payments associated with the cancer medication Jemperli. The disagreement stems from a 2014 agreement involving Tesaro, GSK's subsidiary, which acquired rights to develop and market Jemperli, a treatment for specific endometrial cancers.
Tesaro initiated a lawsuit in November 2025, accusing AnaptysBio of breaching their contract and seeking to terminate the deal, reduce royalty payments, and obtain a permanent license. AnaptysBio countersued, alleging Tesaro violated exclusivity terms by engaging with rival PD-1 drugs and failing to optimize Jemperli's market potential. AnaptysBio also accused GSK of interfering with the agreement.
A trial to settle the allegations is scheduled to commence on July 14, 2026, with the court expected to review AnaptysBio's motion in early March. Royalty payments under the agreement are structured in tiers based on sales, ranging from 8% to 25%, and are expected to continue until at least 2035 in the United States and 2036 in the European Union.
