Sosei : to Host Investor Day in Tokyo featuring 2017 Nobel Prize Winner Dr. Richard Henderson

Sosei to Host Investor Day in Tokyo featuring 2017 Nobel Prize

Winner Dr. Richard Henderson

Tokyo, Japan and London, UK, 26 January 2018 - Sosei Group Corporation (TSE Mothers Index: 4565) ("Sosei" or the "Company"), the world leader in GPCR medicine design and development, announced today it will hold its Investor Day from 10:00 a.m. JST on Wednesday, 14 March 2018 at the Hotel New Otani in Tokyo. Entry on the day will commence from 09:30 a.m.

The Investor Day will be held in the Fuyo Room at the Hotel New Otani and hosted by members of Sosei's senior management team, with a keynote presentation from Dr. Richard Henderson, co-founder of Heptares Therapeutics and 2017 Nobel Prize winner in Chemistry for his pioneering work in the field of cryo-electron microscopy. Sosei will provide an update on its corporate strategy as well as insight to its GPCR structural design approach and pipeline programs, including HTL0018318, its wholly-owned Phase 2 ready candidate for dementia with Lewy bodies (DLB) in Japan.

Invitation cards will be sent out via mail today to all shareholders on the register as of 31 December 2017. RSVP is required for in-person attendance at the Investor Day, so please ensure you return the required section of your invitation card by no later than the close of business on Friday, 16 February 2018. Shareholders are also reminded to please bring the remainder of their invitation cards on the day of the event to present at the front registration desk.

A webcast replay of the Investor Day and selected materials will be available following completion of the event on the Company'swebsite.

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About Sosei

Sosei is an international biopharmaceutical company focused on the design and development of new medicines originating from its proprietary GPCR-targeted StaR® technology and structure-based drug design platform capabilities. The Company is advancing a broad and deep pipeline of partnered and wholly owned product candidates in multiple therapeutic areas, including CNS, cancer, metabolic diseases and other rare/specialty indications. The Company's leading clinical programs include a proprietary Phase 2 candidate for dementia with Lewy bodies (DLB) in Japan, together with partnered candidates aimed at the symptomatic treatment of Alzheimer's disease (with Allergan) and immuno-oncology approaches to treat cancer (with AstraZeneca). Sosei's additional partners and collaborators include Novartis, Teva, Pfizer, Daiichi-Sankyo, PeptiDream, Kymab and MorphoSys. The Company is headquartered in Japan with R&D facilities in the UK.

Sosei is listed on the Mothers Index of the Tokyo Stock Exchange (ticker: 4565). For more information, please visithttp://www.sosei.com/en/.

Contact information

Chris Cargill, Head of Investor Relations and Corporate Communications [phone]

Harumi Banse, Corporate Communications (Japan) [phone]

Citigate Dewe Rogerson (for International media) Mark Swallow, David Dible [phone]

Sosei Forward-looking statements

This press release may contain forward-looking statements, including statements about the discovery, development and commercialisation of products. Various risks may cause Sosei's actual results to differ materially from those expressed or implied by the forward-looking statements, including: adverse results in clinical development programmes; 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 commercialise 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 commercialisation 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.