Sosei Heptares Regains Full Ownership from GSK of HTL0027477, a Clinic-ready, First-in-Class Oral GPR35 Agonist for Inflammatory Bowel Disease

• GPR35 is a novel target with an established genetic association to IBD
  
• UK regulatory approval received to commence first-in-human studies
• Return of rights follows change in immunology research strategy by GSK

Tokyo, Japan and Cambridge, UK, 21 March 2024 – Sosei Group Corporation (“Sosei Heptares” or “the Company”; TSE: 4565) announces it has regained full ownership from GSK of HTL0027477 (formerly GSK4381406), a clinic-ready, highly selective, first-in-class, oral GPR35 agonist in development as a potential new treatment for Inflammatory Bowel Diseases (IBD).

GPR35 is an important orphan G protein-coupled receptor (“GPCR”) with an established genetic association to IBD, for which there remains significant unmet need for millions of sufferers worldwide.

HTL0027477 was designed by Sosei Heptares using its proprietary structure-based drug design (SBDD) platform and licensed to GSK in 2020. Since then, HTL0027477 has been advanced through a joint development program, generating promising mechanistic, preclinical efficacy and safety data suggesting that it may have the potential to improve intestinal barrier function and reduce visceral pain in gastrointestinal indications such as ulcerative colitis and irritable bowel syndrome. The UK Medicines and Healthcare products Regulatory Agency (“MHRA”) gave approval in mid-2023 for HTL0027477 to be investigated in first-in-human studies.

The process to regain rights to the program was initiated in late 2023 following a decision by GSK to deprioritize and discontinue its development following changes to both its immunology research strategy and immunology research leadership. The decision was not based on any scientific, preclinical or safety data related to the candidate.

Sosei Heptares regained full ownership of the HTL0027477 program including associated intellectual property licensed by Sosei Heptares to GSK, and preclinical data generated under the partnership for no upfront payment. Sosei Heptares expects to determine the optimal strategy for further clinical development of the program, which could include in-house development and re-partnering.

Matt Barnes, President of Heptares Therapeutics and Head of UK R&D, commented: “The return of the GPR35 agonist program, with its first-in-class mechanism of action and potential to address major unmet needs in IBD worldwide, is a strong addition to our growing clinical pipeline. This exciting program has already delivered highly promising preclinical data that support its potential as a new therapy for IBD and is poised to enter a Phase 1 clinical trial. This presents a clear opportunity for Sosei Heptares to further advance this program while determining the optimal path forward for further development and commercialization.”