SAREUM HOLDINGS PLC

("Sareum" or "the Company")

Sareum notes proposed acquisition of Sierra Oncology by GSK

Cambridge, UK, 13 April 2022 - Sareum Holdings plc (AIM: SAR), the specialist drug development company, notes that Sierra Oncology, Inc ("Sierra"), the licence holder for SRA737 (a novel Chk1 inhibitor), has agreed to be acquired by GlaxoSmithKline plc ("GSK") for US$1.9 billion in cash. The transaction is expected to close in the third quarter of 2022 or before. GSK has noted that the key driver of the acquisition was momelotinib, a drug Sierra is developing for the treatment of myelofibrosis, which reported positive topline results in a Phase III study in January 2022.

SRA737 was 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. SRA737 was licensed to Sierra in September 2016.

During the second half of 2021 and early 2022, Sierra noted it is finalising the design of several potential clinical trials to advance its pipeline candidates, including SRA737, which it said could start in 2022. These trials would investigate SRA737 in combination with other agents in haematologic and solid tumour indications.

Under an amended US$299m licensing deal on SRA737 between Sierra and CRT Pioneer Fund LP, Sareum is eligible to receive a 27.5% share of any future milestone payments as well as royalties on any future sales. The dosing of the first patient with SRA737 in any new clinical trial would result in a US$2.0m payment from Sierra, with 27.5% of this due to Sareum.

The full announcement made by Sierra can be viewed here.

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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 through preclinical development as therapies for autoimmune diseases, including the 'cytokine storm' immune system overreaction to Covid-19 and other viral infections, (SDC-1801) and cancer immunotherapy (SDC-1802).

Sareum also has an economic interest in SRA737, a clinical-stage oral, selective Checkpoint kinase 1 (Chk1) inhibitor that targets cancer cell replication and DNA damage repair mechanisms. Preliminary Phase 2 and comprehensive preclinical data suggest SRA737 may have broad application in combination with other oncology and immune-oncology drugs in genetically defined patients.

SRA737 was 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. SRA737 was licensed by CRT Pioneer Fund (CPF) to Sierra Oncology Inc. Sierra continues to explore options that would enable the development of SRA737 to advance.

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 

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