• The acquisition includes IDRX-42, a selective KIT tyrosine kinase inhibitor (TKI) designed to treat gastrointestinal stromal tumors (GIST)
• IDRX-42 offers the potential to address all of the key KIT mutations in GIST that drive tumor growth and progression and promote tolerance, gaps in current therapies
• The acquisition adds to GSK’s growing portfolio of gastrointestinal (GI) cancers
• GSK will pay up to $1.15 billion

PLYMOUTH, Mass.–(BUSINESS WIRE)–GSK plc (LSE/NYSE: GSK) and IDRx, Inc. (IDRx) today announced that they have entered into an agreement whereby GSK will acquire IDRx, a Boston-based, clinical-stage biopharmaceutical company dedicated to developing precision therapeutics for the treatment of GIST. Under the agreement, GSK will pay $1 billion up front, with the potential for an additional $150 million based on the success of regulatory approval milestone payments. The acquisition includes the lead molecule, IDRX-42, a highly selective KIT TKI developed as a first- and second-line therapy for the treatment of GIST.

GIST is most common in the GI tract with 80% of cases driven by mutations in the KIT gene that lead to growth, proliferation, and survival of tumor cells (primary or activating mutations).1 90% of patients with treated in the first line. create new KIT ​​mutations (secondary or resistance mutations) that often lead to relapse limiting therapeutic options.2 Currently, there are no approved TKIs that inhibit the entire spectrum of clinically relevant primary and secondary mutation of KIT.

IDRX-42 shows activity against all significant primary and secondary KIT mutations, designed to improve outcomes in patients with GIST. This breadth of mutational coverage, in addition to the high selectivity that improves tolerance, provides the potential for a best-in-class profile.

Luke Miels, Chief Commercial Officer, GSK, said: IDRX-42 supports our growing portfolio in gastric cancers. This acquisition is consistent with our approach to acquiring properties 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 initial 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. -care. We expect to accelerate its development in 2025 to revolutionize treatment.

Updated clinical data from StrateGIST 1, an ongoing phase I/Ib trial of IDRX-42 in patients with advanced GIST, was presented in an oral presentation at the Connective Tissue Oncology Society (CTOS) 2024 Annual Meeting. These data show promising anti-tumor activity of IDRX-42 in patients with advanced GIST with a manageable safety profile. In patients with second-line or larger GIST, and among all subsets of KIT mutations, the objective response rate (ORR) by modified RECIST v1.1 of the overall efficacy was assessed as population is 29% (n = 87), including a complete response (CR) and 24 partial responses (PRs). Among patients with one prior line of therapy, the ORR was 53% (n=15) including one CR and 7 PRs.3

In all patients, two of the PRs were awaiting confirmation at the time of data cut-off, of which two were later confirmed. Emerging durability data from StrateGIST 1 is also favorable. IDRX-42 was generally well tolerated and treatment-related adverse events (TRAEs) were generally low grade at the recommended phase Ib dose.4

Tim Clackson, CEO, IDRx, said: We look forward to working with GSK to develop IDRX-42 for patients with GIST as there has been no major improvement in the standard of care for nearly 20 years. Combining our experience to date with GSK’s expertise in GI cancers, global clinical development capabilities, and strong commercial presence in oncology will help to accelerate the development of this novel drug for patients.

GSK has a growing development portfolio targeting important medical needs in GI cancers, including ongoing trials of dostarlimab and GSK5764227 (GSK’227), a B7-H3-targeted antibody-drug conjugate. This agreement reflects GSK’s portfolio approach to identifying potentially best-in-class molecules with targeted mechanisms of action. The transaction supports GSK’s ambitions for growth through 2031 and beyond.

IDRx was founded in 2021 with the mission to address the limitations of today’s precision cancer drugs with highly potent and selective targeted therapies to stop key tumor escape mechanisms and prolong response. in therapy patients. 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 co-founders include 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 equity incentives) in IDRx up to $1.15 billion in total cash consideration, consisting of an initial payment of $1 billion with the potential for an additional $150 million in success-based regulatory approval milestone payments. GSK is also responsible for success-based milestone payments as well as tiered royalties for the IDRX-42 loan of Merck (NS:) KGaA, Darmstadt, Germany.

This transaction is subject to customary conditions, including applicable regulatory agency clearances under the US Hart-Scott-Rodino Act.

For IDRx, Centerview Partners LLC acted as exclusive financial advisor and Goodwin Procter LLP as legal counsel. For GSK, Leerink Partners LLC acted as exclusive financial advisor.

About GIST

Gastrointestinal stromal tumors (GIST) are the most common subtype of soft tissue sarcoma, with about 80,000 to 120,000 patients diagnosed with GIST each year worldwide. leads to the growth, proliferation, and survival of tumor cells (primary or activating mutations in exons 9 and 11).6 In addition, about 90% of patients treated with first-line develop new KIT mutations (secondary or resistance mutations in exon 13 and 17) that often lead to relapse with limited therapeutic options.7 There are no approved TKIs that prevent the entire spectrum of clinically relevant primary and secondary KIT mutations.

IDRX-42s

IDRX-42 is a highly selective, screening small molecule tyrosine kinase inhibitor (TKI) designed to target all-important 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 failure to imatinib, and Orphan Drug designations 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 selectively targeted therapies to stop key tumor escape mechanisms and prolong therapy response.

About GSK

GSK is a global biopharma company with a mission to bring together science, technology, and talent to get ahead of disease. Find out 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, involve risks and uncertainties that could cause actual results to differ materially from those are planned. Such factors include, but are not limited to, those described under Item 3.D Risk factors in GSK’s Annual Report on Form 20-F for 2023, and GSK’s Q3 Results for 2024.

Registered in England and Wales:
Number 3888792

Registered Office:
79 New Oxford Street
London
WC1A 1DG

References

1 Bauer S, George S, von Mehren M, Heinrich MC. Early and Next Generation KIT/PDGFRA Kinase Inhibitors and the Future of Treatment for Advanced Gastrointestinal Stromal Tumors. Front Oncol. 2021 Jul 12;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 for overcoming IM resistance in GIST. Signaling in Cell Commun. 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. 2016 Feb;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 for Advanced Gastrointestinal Stromal Tumors. Front Oncol. 2021 Jul 12;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 for overcoming IM resistance in GIST. Signaling in Cell Commun. 2024 Feb 27;22(1):153.

See the original version on businesswire.com: https://www.businesswire.com/news/home/20250112698434/en/

IDRx contacts

Media:
1AB
Katie Engleman
[email protected]

Investors:
1AB
Steve Class
[email protected]

GSK questions

Media:
Tim Foley, +44 (0) 20 8047 5502 (London)
Sarah Clements, +44 (0) 20 8047 5502 (London)
Kathleen Quinn, +1 202 603 5003 (Washington DC)
Lyndsay Meyer, +1 202 302 4595 (Washington DC)

Investor Relations:
Annabel Brownrigg-Gleeson, +44 (0) 7901 101944 (London)
James Dodwell, +44 (0) 20 8047 2406 (London)
Mick Readey, +44 (0) 7990 339653 (London)
Camilla Campbell, +44 (0) 7803 050238 (London)
Steph Mountifield, +44 (0) 7796 707505 (London)
Jeff McLaughlin, +1 215 751 7002 (Philadelphia)
Frannie DeFranco, +1 215 751 4855 (Philadelphia)

Source: GSK plc and IDRx, Inc.