HTL0039732 is a novel EP4 antagonist with potential to treat a wide range of cancers in combination with other immunotherapiesTOKYO, Japan and LONDON and CAMBRIDGE, United Kingdom, July 22, 2022 (GLOBE NEWSWIRE) — Sosei Group Corporation (“the Company”; TSE: 4565), an international biopharmaceutical company and world-leader in GPCR1-focused structure-based drug design (SBDD) and development, and Cancer Research UK, the world’s largest private funder of cancer research, today announce the signing of an agreement to bring Sosei Heptares’ cancer immunotherapy drug candidate into a first-in-human trial. Under the Clinical Trial and Licence Agreement (CTLA), Cancer Research UK’s Centre for Drug Development will sponsor, design and execute a Phase I/IIa clinical trial of HTL00397322, a novel selective EP4 antagonist. Sosei Heptares will be responsible for CTA enabling activities, including GLP toxicology, IMP manufacture1 and other necessary pre-clinical studies in preparation for the opening of the clinical trial. Sosei Heptares holds a licence to the results generated under the trial to continue the clinical development and commercialisation of HTL0039732. HTL0039732 has been proposed for a range of cancers including microsatellite stable3 colorectal, gastroesophageal, head and neck and castrate resistant prostate cancer. Many people with these types of cancer have missed out on the benefits that common immunotherapies, such as PD1/L1 checkpoint inhibitors4, have brought to other cancer types. The hope is that this trial could find that HTL0039732 is an effective immunotherapy for these under-served patient populations. HTL0039732 is a type of immunotherapy known as an EP4 antagonist, which means it selectively binds and blocks a specific type of prostaglandin receptor5 called EP4. Prostaglandin E2 (PGE2) mediated signalling through EP4 can trigger cancer cells to evade the immune system and can also influence tumour cell growth. Therefore, blocking this type of receptor may improve patient survival, especially if used in combination with another immunotherapy. The Director of Cancer Research UK’s Centre for Drug Development, Dr Nigel Blackburn, said: “People with these cancer types have, to date, largely missed out on some of the remarkable advances in the field of immunotherapy. “We are therefore thrilled to be partnering with Sosei Heptares to bring their novel immunotherapy candidate into human trials. The hope is that with more trials like this, all cancer patients will eventually be able to benefit from this potentially life-saving form of cancer treatment.” Matt Barnes, President of Heptares Therapeutics and Head of UK R&D, commented: “We are extremely pleased to collaborate with Cancer Research UK to advance HTL0039732 into Phase I/IIa clinical trials and take a step towards bringing new treatments to cancer patients. “HTL0039732 was rationally designed using our highly productive SBDD platform specifically for this type of immunotherapy approach and as such we believe it offers the potential to be a best-in-class EP4 antagonist agent.” Notes to Editors Further details of HTL0039732 will be presented at the 2022 Medicinal Chemistry Gordon Research Conference in early August 2022. 1GPCRs (G Protein-Coupled Receptors) are a super-family of integral cell membrane proteins that are present on cells and tissues throughout the body. GPCRs are involved in signalling pathways that influence a wide range of biological processes and are important drug targets implicated in many human diseases and disorders. CTA – Clinical Trial Authorisation; GLP – Good Laboratory Practice; IMP – Investigational Medicinal Product 2HTL0039732 will be evaluated as both a combination therapy and a monotherapy 3Approximately 80-85% of colorectal cancer patients are classified as ‘Microsatellite Stable’ which means they have low instability in short, repeated sequences of DNA in their tumours, known as microsatellites. MSS tumors often exist in an environment that suppresses the immune system and do not respond well to immunotherapies. 4Checkpoint inhibitors block proteins, known as checkpoint proteins, that stop the immune system from attacking the cancer cells. Examples of checkpoint inhibitors include pembrolizumab (Keytruda), ipilimumab (Yervoy), nivolumab (Opdivo) and atezolizumab (Tecentriq). 5The prostaglandins are a group of lipids made at sites of tissue damage or infection that are involved in dealing with injury and illness. They control processes such as inflammation, blood flow, the formation of blood clots and the induction of labor. About Cancer Research UK’s Centre for Drug Development Cancer Research UK has an impressive record of developing novel treatments for cancer. The Cancer Research UK Centre for Drug Development has been pioneering the development of new cancer treatments for 25 years, taking over 140 potential new anti-cancer agents into clinical trials in patients. It currently has a portfolio of 21 new anti-cancer agents in preclinical development, Phase I or early Phase IIa clinical trials. Six of these new agents have made it to market including temozolomide for brain cancer, abiraterone for prostate cancer and rucaparib for ovarian cancer. Two other drugs are in late development Phase III trials. www.cruk.org.uk/cdd About Cancer Research UK Cancer Research UK is the world’s leading cancer charity dedicated to saving lives through research.Cancer Research UK’s pioneering work into the prevention, diagnosis and treatment of cancer has helped save millions of lives.Cancer Research UK receives no funding from the UK government for its life-saving research. Every step it makes towards beating cancer relies on vital donations from the public.Cancer Research UK has been at the heart of the progress that has already seen survival in the UK double in the last 40 years.Today, 2 in 4 people survive their cancer for at least 10 years. Cancer Research UK’s ambition is to accelerate progress so that by 2034, 3 in 4 people will survive their cancer for at least 10 years.Cancer Research UK supports research into all aspects of cancer through the work of over 4,000 scientists, doctors and nurses.Together with its partners and supporters, Cancer Research UK’s vision is to bring forward the day when all cancers are cured. For further information about Cancer Research UK’s work or to find out how to support the charity, please call +44 (0)300 123 1022 or visit www.cancerresearchuk.org. Follow us on Twitter and Facebook. About Sosei Heptares We are an international biopharmaceutical group focused on the discovery and early development of new medicines originating from our proprietary GPCR-targeted StaR® technology and structure-based drug design platform capabilities. We are advancing a broad and deep pipeline of novel medicines across multiple therapeutic areas, including neurology, immunology, gastroenterology and inflammatory diseases. We have established partnerships with some of the world’s leading pharmaceutical companies and multiple emerging technology companies, including AbbVie, AstraZeneca, Biohaven, Genentech (Roche), GSK, Neurocrine Biosciences, Novartis, Pfizer, Takeda and Verily. Sosei Heptares is headquartered in Tokyo, Japan with corporate and R&D facilities in Cambridge, UK. “Sosei Heptares” is the corporate brand and trademark of Sosei Group Corporation, which is listed on the Tokyo Stock Exchange (ticker: 4565). Sosei, Heptares, the logo and StaR® are trademarks of Sosei Group companies. For more information, please visit https://soseiheptares.com/LinkedIn: @soseiheptaresco | Twitter: @soseiheptaresco | YouTube: @soseiheptaresco Enquiries: Cancer Research UKEllie Bennett, Media Officer+44 (0)20 3469 5370 or, out of hours, on +44 (0)7884 466 868 | eleanor.bennett@cancer.org.uk Sosei Heptares – Media and Investor RelationsHironoshin Nomura, Chief Financial Officer Shinichiro Nishishita, VP Investor Relations, Head of Regulatory DisclosuresCandelle Chong, SVP Investor Relations and Corporate StrategyJapan: +81 (0)3 5210 3399 | United Kingdom: +44 (0)1223 949390 | IR@SoseiHeptares.com MEDiSTRAVA Consulting (for International Media)Mark Swallow, Frazer Hall, Eleanor Perkin+44 (0)203 928 6900| SoseiHeptares@medistrava.com Sosei Heptares Forward-looking statementsThis press release contains forward-looking statements, including statements about the discovery, development and commercialization of products. 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