TESARO Pursues Litigation Against AnaptysBio For Alleged Material Breach Of Jemperli Agreement

(RTTNews) - GSK plc.'s (GSK) subsidiary TESARO Inc. has commenced litigation against AnaptysBio Inc. (ANAB), contending that AnaptysBio has materially violated the terms of their licensing agreement related to the oncology drug Jemperli.

In March 2014, TESARO, then an independent publicly listed company, entered into a strategic immuno-oncology collaboration with AnaptysBio. Under the agreement, AnaptysBio granted TESARO exclusive rights to develop and commercialize antibody programs targeting PD-1, TIM-3, and LAG-3, including both monospecific and dual-reactive antibody candidates.

As part of the collaboration, AnaptysBio licensed the PD-1 antibody Dostarlimab to TESARO, which later received FDA approval as Jemperli in 2021.

TESARO was acquired by GSK in 2019. The following year, i.e. in August 2020, AnaptysBio sent a notice of breach to GlaxoSmithKline and TESARO, stating that GSK is in breach of its obligations under the Collaboration and Exclusive License Agreement originally executed between TESARO and AnaptysBio. The notice indicated that, as a result, the agreement would terminate with respect to PD-1 antagonists, including Dostarlimab, which at the time was in the late stages of clinical development, effectively revoking all licenses and rights previously granted for the program.

Following the dispute, AnaptysBio and GlaxoSmithKline amended their immuno-oncology collaboration agreement in October 2020, providing AnaptysBio with increased royalties on Dostarlimab sales under the collaboration, among other things.

Now, with TESARO filing a fresh salvo against AnaptysBio, alleging a material breach of their existing license agreement for Jemperli, TESARO claims the right to terminate the current license, secure a perpetual and irrevocable license to Dostarlimab, and reduce the royalties and milestone payments owed to AnaptysBio by 50%.

GSK and TESARO stand by the view that the initial allegations by AnaptysBio are entirely without merit.

GSK closed Thursday's trading at $46.11, down 0.50%. ANAB closed the day's trading at $37.66, up 1.76%.

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