GSK opens JPM Healthcare Conference with US $1B+ IDRx acquisition

USA – GSK has acquired privately-held biotech company IDRx for US $1 billion upfront, adding a promising rare cancer treatment to its portfolio.

If all agreed-upon milestones are reached, GSK could pay an additional US $150 million. This acquisition marks the first significant deal of the 2025 JP Morgan Healthcare Conference, which began on Monday.

The purchase will bring GSK a new oncology program, IDRX-42, which is designed to treat gastrointestinal stromal tumors (GIST).

This acquisition mirrors GSK’s 2022 buyout of Sierra Oncology, which provided the company with the JAK inhibitor Ojjaara (momelotinib), approved in 2023.

Luke Miels, GSK’s Chief Commercial Officer, noted that the new deal further strengthens the company’s oncology portfolio.

GSK’s Chief Scientific Officer, Tony Wood, previously shared that the company is focused on creating steady momentum for its oncology pipeline.

The IDRx acquisition, along with a recent licensing agreement with Rgenta to develop splice modulators for cancer, aligns with this approach.

The collaboration with IDRx began last month after the biotech company presented its program to GSK executives. Miels and Wood were particularly impressed by IDRX-42.

Miels also mentioned that the drug’s potential market echoes his experience at AstraZeneca, where he contributed to the success of the lung cancer drug Tagrisso, which filled treatment gaps for specific tumor mutations like EGFR.

IDRX-42 aims to treat GIST by targeting the KIT mutation found in over 80% of GIST tumors. GSK sees an opportunity to improve upon existing treatments like Novartis’ Gleevec, which has been used for GIST since 2008.

Miels noted that while there are about 6,000 GIST patients in the U.S. and 5,000 in the EU, global estimates range from 80,000 to 120,000 due to variations in diagnoses.

Durability is a key consideration for IDRX-42, as GIST patients typically survive at least five years.

GSK plans to begin a study in second-line patients this year, followed by a study in first-line patients soon after.

Miels emphasized that the company won’t wait for the results of the second-line study before starting the first-line trial.

IDRx had initially targeted a pivotal study around mid-2025. At the ASCO meeting in June, the company shared Phase 1 data showing that IDRX-42 shrank tumors in 23% of patients overall, and 43% of second-line patients.

IDRx had raised US US $120 million in a Series B funding round in August, with investors including RA Capital, Commodore Capital, and Blackstone.

The company had licensed IDRX-42 from Merck KGaA prior to its public unveiling in 2022.