Sareum submits Clinical Trial Authorisation application to UK MHRA for development of TYK2/JAK1 inhibitor SDC-1801 and provides an Operational Update

Sareum Holdings PLC

(“Sareum” or the “Company”)

Sareum submits Clinical Trial Authorisation application to UK MHRA for development of TYK2/JAK1 inhibitorSDC-1801 and provides an Operational Update

• Clinical Trial Authorisation application for a Phase 1a/b clinical trial with SDC-1801 submitted to the UK Medicines and Healthcare Products Regulatory Agency
• Sareum has made significant progress advancing SDC-1801 towards clinical development and plans to initiate Phase 1 clinical trials in 2022, with a study in psoriasis targeted for 2023
  • The Company continues to progress translational studies to support its cancer immunotherapy candidate, SDC-1802
• New EU patent granted (April 2022), protecting the SDC-1802 molecule and pharmaceutical preparations as a therapeutic to treat T-cell acute lymphoblastic leukaemia
• Sareum had a cash position of approximately £4.3 million as at 30 June 2022
• A presentation to investors will take place on 4 August 2022 at 10.00am via the Investor Meet Company platform. See below for registration details.

Cambridge, UK, 28July2022 – Sareum Holdings plc (AIM: SAR), the specialist drug development company, today announces that it has submitted an application for a Clinical Trial Authorisation (“CTA”) to the UK Medicines and Healthcare Products Regulatory Agency (“MHRA”) for the development of SDC-1801 as a potential new therapeutic for a range of autoimmune diseases with a focus on psoriasis.

Sareum also provides a broader update on operational activities and pipeline progress.

OPERATIONAL HIGHLIGHTS -STRONG PIPELINE PROGRESS

SDC-1801 (autoimmune disease)

SDC-1801 is a TYK2/JAK1 inhibitor being developed as a potential new therapeutic for a range of autoimmune diseases with an initial focus on psoriasis, an autoimmune condition affecting the skin.

Preclinical development activities required to apply for the CTA have been successfully concluded and, consistent with the Company’s clinical development plan, an application for a CTA has now been filed.

TYK2/JAK1 inhibition has demonstrated benefits in maintaining a healthy immune system and has strong clinical validation in psoriasis and psoriatic arthritis. Psoriasis is an autoimmune dermatological condition affecting more than 60 million adults worldwide, with a market size for potential treatments worth more than US$30 billion. Sareum believes that TYK2/JAK1 inhibition offers potential for increased efficacy in psoriasis, compared with existing approved therapies.

Sareum, working alongside a specialist contract research organisation (CRO), has designed a Phase 1a/b clinical trial with SDC-1801 in healthy subjects and psoriasis patients. Subject to regulatory approval from MHRA, the Phase 1a trial is planned to commence in Q4 2022 and will investigate the safety and tolerability of an oral formulation of SDC-1801 in ascending doses administered to healthy subjects. In addition, the trial will evaluate the effect of SDC-1801 on certain biomarkers of autoimmune disease that could be predictive of efficacy when tested in patients.

The Phase 1a part of the trial is expected to provide safety and dosing information applicable for any future trials in patients with other autoimmune diseases and the acute respiratory symptoms of viral infections, including COVID-19, should the Company decide to progress such trials.

Provided satisfactory safety data is obtained from this initial study, and subject to additional funding, a Phase 1b clinical study will commence in psoriasis patients in 2023. The CRO conducting and managing the studies has extensive experience in conducting trials in inflammatory diseases and will recruit up to 120 subjects at a site in Manchester, UK.

Synthesis of SDC-1801 drug substance under GMP conditions has been completed successfully, with a surplus of material for the planned Phase 1 clinical trials. GMP-compliant manufacture of capsules of SDC-1801, intended for use in the Phase 1 trial, is also complete, and the capsules are undergoing rigorous quality control checks before delivery to the clinical unit.

SDC-1802 (cancer immunotherapy)

Sareum continues to work on the translational studies needed to define the optimal cancer application prior to completing toxicology and manufacturing studies.

In April 2022, the Company was granted a new patent, protecting the SDC-1802 molecule and pharmaceutical preparations thereof as a therapeutic to treat T-cell acute lymphoblastic leukaemia (T-ALL – a cancer of a particular type of white blood cell called a T lymphocyte) and other cancers that are dependent on TYK2 kinase for survival.

Licensed Programme – SRA737: A Selective Chk1 inhibitor

As noted in April 2022, Sierra Oncology, Inc (“Sierra”), the licence holder for SRA737 (a novel Chk1 inhibitor discovered and initially developed by scientists at The Institute of Cancer Research in collaboration with Sareum, and with funding from Sareum and Cancer Research UK, licensed to Sierra in September 2016), has been acquired by GlaxoSmithKline plc (“GSK”) for US$1.9 billion in cash. The transaction was completed on 1 July 2022, and we await an update concerning GSK’s plans in respect of SRA737.

FINANCIALPOSITION

Sareum had a cash position of approximately £4.3 million as at 30 June 2022 (cash of £5.6 million as at 31 December 2021).

Dr Tim Mitchell, CEO of Sareum, commented:

“The CTA application for SDC-1801is an important milestone as we advance this promising potential new therapeutic into the clinic.

“SDC-1801 is aTYK2/JAK1 inhibitor which we believe has significant potential in autoimmune disease and we plan to explore this initially in psoriasis, where we believe dual inhibition of both TYK2 and JAK1 has the potential to offer superior efficacy compared to small molecules currently available and in development inhibiting each of the targets individually.

“We have completed most of the preparatory work for the clinical trialand have built a robust data package to support our ongoing partnering activitiesfor this asset. Subject to regulatory approval by MHRA, we look forward to advancing SDC-1801 into clinical development.”

Investor Presentation:

A presentation to the investment community by Chief Executive Tim Mitchell and Chief Scientific Officer John Reader will take place on 4 August 2022 at 10.00am via the Investor Meet Company platform.

Existing and potential investors wishing to participate in the presentation can register here.

Questions can be submitted before the event via the Investor Meet Company dashboard or at any time via the live presentation via the “Ask a Question” function. Responses from the Q&A session will be published at the earliest opportunity on the IMC platform.

A copy of the presentation will be made available on the Company’s website following the presentation.

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About Sareum

Sareum is a specialist drug development company delivering targeted small molecule therapeutics to improve the treatment of cancer and autoimmune diseases. The Company aims to generate value through licensing its candidates to international pharmaceutical and biotechnology companies at the preclinical or early clinical trials stage.

Sareum is advancing internal programmes focused on distinct dual tyrosine kinase 2 (TYK2) / Janus kinase 1 (JAK1) inhibitors into clinical development as potential new therapies for autoimmune diseases (with an initial focus on psoriasis), respiratory symptoms arising from viral infections and cancer immunotherapy. Sareum is also eligible to receive certain milestone payments and future royalties on SRA737, a clinical-stage, oral, selective Checkpoint kinase 1 (Chk1) inhibitor that targets cancer cell replication and DNA damage repair mechanisms. SRA737 was licensed to Sierra Oncology, which was acquired by GSK in June 2022.

Sareum Holdings plc is listed on the AIM market of the London Stock Exchange, trading under the ticker SAR. For further information, please visit the Company’s website at www.sareum.com