Initiation of Phase 1 Clinical Study with Novel Immuno-Oncology Candidate Triggers US$10 Million Milestone Payment from AstraZeneca to Heptares

TOKYO–(BUSINESS WIRE)–Sosei Group Corporation (“Sosei”; TOKYO Mothers Index: 4565) today
announces Heptares Therapeutics (“Heptares”), the wholly-owned
subsidiary of Sosei Group Corporation, reported that it has been
notified today by its partner AstraZeneca that the first subject has
been dosed with immuno-oncology candidate HTL1071 (AZD4635) in a Phase 1
clinical study, triggering a US$10 million payment from AstraZeneca.

The first-in-human study is being conducted by AstraZeneca in
approximately 50 patients with advanced solid malignancies and with
non-small cell lung cancer. The primary objective is to determine the
maximum tolerated dose (MTD) of HTL1071 alone and in combination with
durvalumab (MEDI4736), an investigational human monoclonal antibody
directed against PDL1. Pending the determination of the MTD, a Phase 2
trial is planned to investigate further the safety, tolerability,
pharmacokinetics and anti-tumour activity of the selected doses.

HTL1071 is an orally available, small molecule adenosine A2A receptor
antagonist, and the lead candidate in a portfolio of A2A antagonists
discovered by Heptares using its proprietary structure-based drug design
platform. This portfolio was licensed to AstraZeneca in August 2015 for
development and commercialisation across a range of cancers, with an
associated R&D collaboration designed to discover further A2A
antagonists for development in cancer immunotherapy.

Tim Tasker, Heptares’ Chief Medical Officer, said: “The production of
adenosine is a recently identified mechanism employed by tumour cells to
suppress T cell activity and evade destruction. The initiation of this
first clinical study in the A2A antagonist immuno-oncology programme
with AstraZeneca is an important milestone for Heptares and we are
excited to see how the results from preclinical studies translate into
potential new medicines for cancer patients. This is the second
programme in our partnered pipeline to progress into the clinic, the
first being the M1 agonist programme, licensed to Allergan, in which two
novel compounds are undergoing clinical studies as potential new
medicines for cognitive impairment in Alzheimer’s disease and other
neurological indications.”

Susan Galbraith, Vice President, Head of Oncology in AstraZeneca’s
Innovative Medicines and Early Development Unit, said “Immuno-oncology
is one of four key oncology platforms for AstraZeneca. In building our
immuno-oncology portfolio, we believe that blocking adenosine A2A
receptor could enhance the efficacy of immune checkpoint inhibition via
PDL1, CTLA4 and enhance the activity of CD73 inhibition. This innovative
approach could help drive an immune attack on cancers, creating novel
treatments with the potential to transform the lives of patients.”

About Heptares Therapeutics

Heptares is a clinical-stage company creating transformative medicines
targeting G protein-coupled receptors (GPCRs), a superfamily of 375
receptors linked to a wide range of human diseases. Heptares’
proprietary StaR® technology and structure-based drug design (SBDD)
capabilities enable us to engineer and develop drugs for highly
validated, yet historically undruggable or challenging GPCRs. Using this
approach, we are building an exciting pipeline of new medicines (small
molecules and biologics) with the potential to transform the treatment
of Alzheimer’s disease, schizophrenia, cancer immuno-oncology, migraine,
addiction, metabolic disease and other indications. We have partnerships
for our novel candidates and technologies with leading pharmaceutical
and biotechnology companies, including Allergan, AstraZeneca, Kymab,
MedImmune, MorphoSys, Pfizer and Teva.

Heptares is a wholly owned subsidiary of Sosei Group Corporation. For
more information, please visit www.heptares.com
and www.sosei.com/en.

About Sosei

Sosei is a biopharmaceutical company originating from Japan but with
global presence. Sosei’s primary business model is based on identifying
novel and/or differentiated product assets or technology platforms and,
through supporting these in preclinical and clinical development and
establishing commercial partnerships, advancing new medicines to
patients worldwide.

For further information about Sosei, please visit www.sosei.com/en.

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Sosei Group Corporation
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Harumi
BANSE, +81-(0)3-5210-3399
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or
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