GSK Acquires IDRx for $1 Billion

IDRx, a Boston-based, clinical-stage biopharm dedicated to developing precision therapeutics for the treatment of gastrointestinal stromal tumors (GIST) is being acquired by GSK. Under the agreement, GSK will pay $1 billion upfront, with potential for an additional $150 million success-based regulatory approval milestone payment. The acquisition includes lead molecule IDRX-42 being developed as a first- and second-line therapy for GIST.

Gastrointestinal stromal tumors are the most common subtype of soft tissue sarcoma, with about 80,000 to 120,000 patients diagnosed with GIST per year worldwide. GIST typically presents in the GI tract with 80% of cases driven by mutations in the KIT gene that lead to the growth, proliferation, and survival of tumor cells.  Additionally, about 90% of patients treated in the first-line develop new KIT mutations that typically lead to relapse with limited therapeutic options. Currently, there are no approved therapies that inhibit the full spectrum of primary and secondary mutations in KIT.

IDRX-42 is a highly selective, investigational small molecule tyrosine kinase inhibitor (TKI) that has demonstrated activity against all key primary and secondary KIT mutations. This breadth of mutational coverage, in addition to high selectivity which could improve tolerability, provides potential for a best-in-class profile. FDA has granted IDRX-42 Fast Track and Orphan Drug designations for the treatment of GIST.

Said IDRx CEO Tim Clackson, “We are looking forward to working with GSK to advance IDRX-42 for patients with GIST given there have been no major advances to the standard of care for almost 20 years. Combining our experience to date with GSK’s expertise in GI cancers, global clinical development capability, and strong commercial presence in oncology will help to accelerate the development of this novel medicine for patients.”

IDRx was founded in 2021 with a mission to address the limitations of today’s precision cancer medicines with highly potent and selective targeted therapies to stop key tumor escape mechanisms and prolong patients’ response to therapy. (Source: IDRx Website, 13 January, 2025)