GSK has passed on the chance to go all-in on one of three programs in a cancer collaboration with Ideaya Biosciences, but the precision medicine company feels fine about the decision.
GSK and Ideaya signed a $100 million deal in June 2020 to cover three synthetic lethality programs. One of these was looking at a protein-coding gene called methionine adenosyltransferase 2a (MAT2A) in patients with solid tumors with methylthioadenosine phosphorylase (MTAP) deletion. These patients represent about 15% of all those with solid tumors, the biotech said.
The resulting MAT2A inhibitor is called IDE397. But in a second-quarter earnings this morning, Ideaya revealed that GSK has waived its rights to exercise an option for the exclusive license to IDE39 or any other MAT2A-targeting compounds Ideaya will work on.
For Ideaya’s part, the company sees the sense in GSK’s decision, pointing to the Big Pharma’s move to terminate two programs, a PRMT5 inhibitor and PRMT1 inhibtor, in February. Both of these had been considered as potential combination therapy partners for IDE397 when the collaboration was signed, and with both programs gone the strategic rationale for this particular partnership had become “less compelling.”
While Ideaya was understanding, the market was not. The company's shares declined 37% to $9.72 Monday morning, compared to a prior close of $15.65.
With IDE397 fully back in Ideaya’s hands, the company will power ahead with development alone. The drug is in a phase 1/2 trial in advanced solid tumors and, with almost $324 million in cash and securities in hand, the company has sufficient capitalization to continue the phase 2 program.
Ideaya still has another Big Pharma involved with IDE397. In July, the company entered into a clinical trial collaboration and supply agreement with Amgen to clinically evaluate IDE397 in combination with AMG 193—Amgen's small molecule MTA-cooperative PRMT5 inhibitor—in MTAP-null solid tumors.
GSK’s decision on IDE397 doesn’t mean it's severing links with Ideaya entirely, as the companies continue to work on the other two targets from the synthetic lethality collaboration. One of these, a DNA Polymerase Theta candidate, is expected to enter the clinic in the first half of 2023. GSK remains on track to nominate a development candidate next year for the other, which is looking for an inhibitor targeting Werner Helicase for tumors with high microsatellite instability.