GSK PLC (LSE:GSK, NYSE:GSK) has stepped up a dispute over rights to its fast-growing cancer drug Jemperli by having its US subsidiary Tesaro sue AnaptysBio in the Delaware Court of Chancery.
Tesaro is asking the court to confirm that alleged breaches of their 2014 licence deal allow it to end the current contract, keep a perpetual licence to the medicine and cut by half the royalty and milestone payments it owes AnaptysBio.
The move follows accusations from AnaptysBio that Tesaro has failed to meet some obligations under the agreement and that it plans to revoke Tesaro’s licence to develop and sell Jemperli, also known as dostarlimab. GSK and Tesaro say those claims are “entirely without merit”.
Jemperli is an immunotherapy medicine used to treat some forms of endometrial cancer, the most common gynaecological cancer in the US. More than 35 countries have approved it.
A licence agreement typically gives a drug company the right to develop and market a medicine invented elsewhere, in return for upfront fees, milestones tied to progress and a royalty, a percentage of sales.
GSK says Jemperli sales are growing strongly after wider approvals and it is running trials in rectal, colon, and head and neck cancers worldwide, too.