GSK has announced its acquisition of IDRx, a biopharmaceutical company specializing in precision therapeutics, for an upfront payment of $1 billion, with potential milestone payments of up to $150 million. This acquisition bolsters GSK's portfolio in gastrointestinal (GI) cancers and brings IDRX-42, a highly selective KIT tyrosine kinase inhibitor (TKI), into its pipeline. The deal aims to address the unmet medical need in gastrointestinal stromal tumors (GIST), a rare cancer affecting 4,000 to 6,000 people in the U.S. annually.
Addressing KIT Mutations in GIST
GIST is characterized by mutations in the KIT gene in approximately 80% of cases, leading to tumor growth in the digestive tract. While first-line treatments exist, about 90% of patients develop secondary KIT mutations, resulting in resistance and relapse. Currently, there are no approved TKIs that can effectively inhibit the full spectrum of clinically relevant KIT mutations. IDRX-42 is designed to target both activating and resistance mutations, offering a potential best-in-class profile.
Promising Clinical Data
IDRX-42 has already been granted Orphan Drug designation by the FDA and is currently undergoing a Phase I/Ib study. Data presented at the Connective Tissue Oncology Society (CTOS) 2024 Annual Meeting showed an objective response rate (ORR) of 29% across all treated patients with advanced GIST. Notably, the ORR increased to 53% in patients who had received one prior line of therapy. The median progression-free survival for third-line patients was 12.9 months.
Strategic Fit for GSK
According to Tony Wood, Chief Scientific Officer, GSK, IDRX-42's "unique ability to target all clinically relevant KIT mutations present in GIST" fills a major gap in the current standard of care. GSK plans to accelerate the development of IDRX-42 in 2025, aiming to transform GIST treatment. Luke Miels, Chief Commercial Officer, GSK, added that the acquisition aligns with GSK's strategy of acquiring assets that address validated targets with clear unmet medical needs.
The acquisition is subject to customary regulatory clearances and is expected to close in the near future. GSK will also assume responsibility for milestone payments and royalties owed to Merck KGaA, who originally licensed IDRX-42 to IDRx.
