- The acquisition includes IDRX-42, a highly selective KIT tyrosine kinase inhibitor (TKI) designed for the treatment of gastrointestinal stromal tumors (GIST).
- IDRX-42 offers potential to address all key KIT mutations in GIST that drive tumor growth and progression and improve tolerability, gaps in current therapies
- The acquisition adds to GSK’s growing portfolio in gastrointestinal (GI) cancers
- GSK will pay up to $1.15 billion
PLYMOUTH, Mass.–( BUSINESS WIRE )–GSK plc (LSE/NYSE: GSK ) and IDRx, Inc . (IDRx) announced today that they have entered into an agreement under which GSK will acquire IDRx, a Boston-based clinical biopharmaceutical company dedicated to developing precision therapeutics for the treatment of GIST. Under the deal, GSK will pay $1 billion up front, with the potential for an additional $150 million based on successful regulatory approval. The acquisition includes the lead molecule, IDRX-42, a highly selective KIT TKI that is being developed as a first- and second-line therapy for the treatment of GIST.
GIST typically occurs in the GI tract with 80% of cases caused by mutations in the KIT gene that lead to the growth, proliferation and survival of tumor cells (primary or activating mutations).1 90% of patients treated with first-line treatment develop new KIT mutations (secondary mutations or resistance mutations ) that usually lead to relapse with limited therapeutic options.2 Currently, there are no approved TKIs that inhibit the entire spectrum of clinically relevant primary and secondary mutations in KIT.
IDRX-42 has demonstrated activity against all key primary and secondary KIT mutations, designed to improve outcomes for patients with GIST. This breadth of mutational coverage, along with high selectivity that could improve tolerability, provides the potential for a best-in-class profile.
Luke Miels, Chief Commercial Officer, GSK, said: IDRX-42 complements our growing portfolio in gastrointestinal cancers. This acquisition is consistent with our approach to acquiring assets that address validated targets and where there is a clear unmet medical need, despite existing approved products.
Tony Wood, Chief Scientific Officer, GSK, said: We are excited by the early data from IDRX-42 and its unique ability to target all clinically relevant KIT mutations present in GIST, a major gap in the current standard of care. We look forward to accelerating its development in 2025 to redefine treatment.
Updated clinical data from StrateGIST 1, an ongoing Phase I/Ib trial of IDRX-42 in patients with advanced GIST, were presented in an oral presentation at the Connective Tissue Oncology Society (CTOS) 2024 Annual Meeting. These data demonstrate promising antitumor activity of IDRX-42 in patients with advanced GIST with a tolerable safety profile. Among patients with second-line or greater GIST, and among all subsets of KIT mutations, the objective response rate (ORR) according to modified RECIST v1.1 in the overall efficacy evaluable population was 29% (n=87), including one complete response (CR) and 24 partial responses (PR). Among patients who had one prior line of therapy, the ORR was 53% (n=15) including one CR and 7 PRs.3
Among all patients, two PRs were awaiting confirmation at the time of data cutoff, and both were subsequently confirmed. The new durability data from StrateGIST 1 was also favorable. IDRX-42 was generally well tolerated and treatment-related adverse events (TRAEs) were mostly of low grade at the recommended phase Ib.4 dose
Tim Clackson, CEO, IDRx, said: We look forward to working with GSK to advance IDRX-42 for patients with GIST as there has been no major advance in the standard of care for almost 20 years. The combination of our track record with GSK’s expertise in GI cancers, global clinical development capability and strong commercial presence in oncology will help accelerate the development of this new drug for patients.
GSK has a growing development portfolio targeting significant medical needs in gastrointestinal cancers, including trials of dostarlimab and GSK5764227 (GSK’227), a B7-H3-targeted antibody-drug conjugate. This agreement reflects GSK’s portfolio approach of identifying potentially best-in-class molecules with targeted mechanisms of action. The transaction supports GSK’s growth ambitions to 2031 and beyond.
IDRx was founded in 2021 with a mission to address the limitations of today’s precision cancer drugs with highly potent and selective targeted therapies to disrupt key mechanisms of tumor escape and prolong patient response to therapy. IDRx investors include Andreessen Horowitz (a16z), Casdin Capital, Nextech Invest, Forge Life Science Partners, RA Capital Management, Commodore Capital, Blackstone (NYSE: ) Multi-Asset Investing and Rock Springs Capital. IDRx is co-founded by George Demetri, MD, FACP, FASCO, FAACR, Nicholas Lydon, Ph.D., Alexis Borisy, Robert Forrester, and Ben Auspitz.
Financial considerations
Under the terms of the agreement, GSK will acquire one hundred percent (100%) of the outstanding equity interests (including all options and other incentive equity) in IDRx for up to $1.15 billion in total cash consideration, which includes an upfront payment of $1 billion with the potential for an additional $150 million based on successful regulatory approval. GSK will also be responsible for the success-based payments as well as multiple royalties owed to IDRX-42 Merck (NS:) KGaA, Darmstadt, Germany.
This transaction is subject to customary conditions, including applicable regulatory agency approvals under the US Hart-Scott-Rodino Act.
For IDRx, Centerview Partners LLC is acting as exclusive financial advisor and Goodwin Procter LLP is acting as legal counsel. For GSK, Leerink Partners LLC is acting as exclusive financial advisor.
About GIST
Gastrointestinal stromal tumors (GIST) are the most common subtype of soft tissue sarcoma, with approximately 80,000 to 120,000 patients diagnosed with GIST annually worldwide.5 GIST typically occurs in the GI tract with 80% of cases driven by mutations in the KIT gene leading to growth, proliferation and survival of tumor cells (primary or activating mutations in exons 9 and 11).6 In addition, about 90% of patients treated first line develops new KIT mutations (secondary mutations or resistance mutations in exons 13 and 17) that usually lead to relapse with limited therapeutic options.7 there are no approved TKIs that inhibit the entire spectrum of clinically relevant primary and secondary mutations in KIT.
About IDRX-42
IDRX-42 is a highly selective, investigational small molecule tyrosine kinase inhibitor (TKI) designed to target all key KIT mutations in GIST. The US Food and Drug Administration (FDA) granted IDRX-42 Fast Track designation for the treatment of patients with GIST after disease progression or intolerance to imatinib, and orphan drug designation for the treatment of GIST.
About IDRx
IDRx is a clinical-stage biopharmaceutical company dedicated to transforming cancer care with intelligently designed precision therapies. IDRx aims to address the limitations of today’s precision cancer drugs with highly potent and selective targeted therapies to disrupt key tumor egress mechanisms and prolong response to therapy.
About GSK
GSK is a global biopharmaceutical company with the purpose of uniting science, technology and talent to get ahead of disease together. Learn more at gsk.com.
Cautionary Statement Regarding Forward-Looking Statements
GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that could cause actual results to differ materially from those anticipated. Such factors include, but are not limited to, those described under Item 3.D Risk Factors in GSK’s 2023 Annual Report on Form 20-F and GSK’s 2024 Third Quarter Results.
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References
1 Bauer S, George S, von Mehren M, Heinrich MC. Early- and next-generation KIT/PDGFRA kinase inhibitors and the future of treatment in advanced gastrointestinal stromal tumor. Front oncol. July 12, 2021; 11:672500.
2 Zhou S, Abdihamid O, Tan F, Zhou H, Liu H, Li Z, Xiao S, Li B. KIT mutations and expression: current knowledge and new insights to overcome IM resistance in GIST. Cellular utility signal. 2024 Feb 27;22(1):153.
3 George et al CTOS 2024
4 George et al CTOS 2024
5 Søreide K, Sandvik OM, Søreide JA, Giljaca V, Jureckova A, Bulusu VR. Global epidemiology of gastrointestinal stromal tumors (GIST): a systematic review of population-based cohort studies. Cancer Epidemiol. February 2016;40:39-46.
6 Bauer S, George S, von Mehren M, Heinrich MC. Early- and next-generation KIT/PDGFRA kinase inhibitors and the future of treatment in advanced gastrointestinal stromal tumor. Front oncol. July 12, 2021; 11:672500.
7 Zhou S, Abdihamid O, Tan F, Zhou H, Liu H, Li Z, Xiao S, Li B. KIT mutations and expression: current knowledge and new insights to overcome IM resistance in GIST. Cellular utility signal. 2024 Feb 27;22(1):153.
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Source: GSK plc and IDRx, Inc.
