Sosei Heptares Announces That The Third Novel Drug Candidate From Its Multi-Target Drug Discovery Collaboration With Pfizer Has Started Clinical Trials

• Dosing of first subject in clinical trial by Pfizer triggers US$5 million payment to Sosei Heptares
• Third candidate nominated by Pfizer to enter clinical trials is an MC4 receptor antagonist targeting Anorexia
• Ninth GPCR-targeted drug candidate overall generated from Sosei Heptares' StaR® technology/SBDD platform to enter clinical development

Tokyo and Cambridge /PRNewswire/ - Sosei Group Corporation ("the Company") (TSE: 4565) has been notified by Pfizer that the first subject in a clinical trial has been dosed with a new drug candidate nominated from the multi-target drug discovery collaboration between the two companies. Achievement of this milestone triggers a payment of US$5 million to Sosei Heptares. This candidate was nominated for advancement by Pfizer in December 2019 generating a US$3 million milestone payment at that time.

Pfizer nominated three distinct clinical candidates from the collaboration with Sosei Heptares during 2019, all of which are now progressing in Phase I clinical trials. These candidates have also now been disclosed by Pfizer as:

• PF-07081532 (an oral GLP1 receptor agonist for Type 2 Diabetes Mellitus and Obesity)
• PF-07054894 (a CCR6 antagonist targeting Inflammatory Bowel Disease) and
• PF-07258669 (an MC4 receptor antagonist for Anorexia)

This candidate is the ninth GPCR-targeted drug candidate overall originating from Sosei Heptares' StaR® technology and structure-based drug design (SBDD) platform to enter clinical trials.

Dr. Rob Cooke, Chief Technology Officer of Sosei Heptares, said: "The start of clinical trials with this new clinical candidate is a further important milestone in our highly productive and longstanding collaboration with Pfizer. It is a clear demonstration of the power of our structure-based design and discovery capabilities when combined with the complementary development expertise of a truly collaborative partner. This productivity is further exemplified by the fact that nine candidates derived from our platform have entered clinical trials across multiple disease areas, with more than 20 active programs underway either with partners or in house. This broad portfolio of exciting new drug candidates has potential to address significant unmet need globally and generate significant future value for shareholders."

About The Agreement with Pfizer
Sosei Heptares and Pfizer entered a multi-target drug discovery collaboration in November 2015 to research and develop potential new medicines directed at GPCR targets across multiple therapeutic areas. Many of these targets have clinical or biological validation as key points for therapeutic intervention potentially targeting a range of diseases but have proven difficult to address with conventional discovery approaches because of inherent technical challenges.

To address these challenges, Sosei Heptares and Pfizer scientists worked closely together to leverage their respective complementary expertise in enabling GPCR-focused structure-based drug design (SBDD) and development directed to the GPCR targets selected by Pfizer. Pfizer is responsible for developing and commercializing any potential therapeutic agents (small molecules or biologics) for each target and will have exclusive global rights to any potential resulting agents.

To date, Sosei Heptares has delivered multiple stabilized receptors (StaR® proteins), X-ray structures and biophysical data on certain programs. These achievements have led to the design and development of novel small molecule candidates, three of which have now entered clinical trials. The progress under this partnership has triggered multiple significant milestone payments from Pfizer, with further payments and potential royalties possible under the agreement, provided the criteria under the agreement are satisfied.

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, including AbbVie, AstraZeneca, Biohaven, Genentech (Roche), Novartis, Pfizer and Takeda and additionally with multiple emerging technology companies. 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://www.soseiheptares.com/

Forward-looking statements
This press release contains forward-looking statements, including statements about the discovery, development and commercialization of products. Various risks may cause Sosei Group Corporation's actual results to differ materially from those expressed or implied by the forward-looking statements, including: adverse results in clinical development programs; failure to obtain patent protection for inventions; commercial limitations imposed by patents owned or controlled by third parties; dependence upon strategic alliance partners to develop and commercialize products and services; difficulties or delays in obtaining regulatory approvals to market products and services resulting from development efforts; the requirement for substantial funding to conduct research and development and to expand commercialization activities; and product initiatives by competitors. As a result of these factors, prospective investors are cautioned not to rely on any forward-looking statements. We disclaim any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.