GSK has completed the acquisition of IDRx, a Boston-based, clinical-stage biopharmaceutical company dedicated to developing precision therapeutics for the treatment of gastrointestinal stromal tumours (GIST).

As announced previously, the acquisition includes lead molecule IDRX-42, an investigational, highly selective tyrosine kinase inhibitor (TKI) that is designed to improve outcomes for patients with GIST. IDRX-42 has demonstrated activity against all clinically relevant primary and secondary KIT mutations, a key medical need in current GIST treatment.

GIST typically presents in the gastrointestinal (GI) tract with 80 percent of cases driven by mutations in the KIT gene that lead to the growth, proliferation, and survival of tumour cells (primary or activating mutations).2 90 percent of patients treated in the first line develop new KIT mutations (secondary or resistance mutations) that typically lead to relapse with limited therapeutic options.

Hesham Abdullah, Senior Vice President, Global Head Oncology R&D, GSK, said, “This acquisition adds to GSK’s growing pipeline of targeted therapeutics for cancers originating in the gastrointestinal tract. We plan to advance IDRX-42 for second line treatment of gastrointestinal stromal tumours, where there are no approved treatments to effectively address all resistance mutations, and accelerate development in an earlier setting.”

The total cash consideration for this acquisition amounts to up to USD 1.15 billion. This includes an upfront payment of USD 1 billion, with the possibility of an additional USD 150 million milestone payment contingent upon success-based regulatory approval. GSK will also be responsible for success-based milestone payments as well as tiered royalties for IDRX-42 owed to Merck KGaA, Darmstadt, Germany.