SAREUM HOLDINGS PLC

(“Sareum” or “the Company”)

HALF-YEARLY RESULTS FOR THE SIX MONTHS ENDED 31 DECEMBER 2017

Sareum Holdings plc (AIM: SAR), the specialist cancer drug discovery and development business, announces its half-yearly results for the six months ended 31 December 2017 and provides an update of significant post-period events.

Operational highlights

• Sareum’s licence partner Sierra Oncology (“Sierra”) made strong progress with the two clinical studies of Chk1 inhibitor SRA737 leading to a significant expansion of the development programme in 2018.
  • SRA737 is being investigated in two Phase 1/2 clinical trials in patients with advanced cancer: a monotherapy study evaluating SRA737 in patients with tumours identified to have genetic aberrations hypothesized to confer sensitivity to Chk1 inhibition, including prostate, ovarian, lung and colorectal cancers; and a drug combination study evaluating SRA737 potentiated by low-dose gemcitabine in four cancer indications, including lung cancer and sarcoma.
  • Sierra presented preclinical data at the AACR-NCI-EORTC congress in October demonstrating that low sub-therapeutic doses of gemcitabine potentiate the anti-tumour effect of SRA737 thereby supporting the design of the combination study.
• Sareum’s TYK2 inhibitor autoimmune disease and cancer research programmes advanced with distinct small molecules moving into candidate selection for preclinical development in each therapeutic area.
  • Further patent grants for the TYK2 kinase programme were received in Japan and China.
• The Company’s small molecule Aurora+FLT3 candidate, targeting opportunities in haematological cancers, continues in preclinical development.

Financial highlights

• In November, Sareum raised £700,000 before expenses through a placement of 100,000,000 new ordinary shares at 0.7p per share to progress its drug development programmes as well as for working capital purposes.
• Loss on ordinary activities (after taxation) of £722,000 (2016: profit of £573,000).
• Cash at bank as at 31 December 2017 was £2,165,000 (2016: £2,305,000).

Post period end

• In February 2018, Sierra provided an update on the SRA737 clinical development programme
  • The Dose Escalation Phase 1 portion of the Phase 1/2 monotherapy trial is in the final stages of optimising the SRA737 dose regimen and the Cohort Expansion Phase 2 portion is ongoing. The Phase 2 portion has been expanded to include more patients across six cancer indications and at a larger number of clinical sites in the UK.
  • For the Low-Dose Gemcitabine Phase 1/2 Combination trial, the Dose Escalation Phase 1 has made progress and the Cohort Expansion Phase 2 is anticipated to commence in the second quarter of 2018. This study is targeting enrollment of 80 genetically selected patients across four indications.
  • Sierra noted its plans to initiate a Phase 1b/2 combination trial of SRA737 with the orally administered PARP inhibitor, niraparib, in patients with prostate cancer. The trial is expected to start in the fourth quarter of 2018 at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust (London, UK).
  • Sierra presented preclinical data providing evidence of synergy between SRA737 and immune checkpoint blockade, and is currently designing a clinical study for this combination.

Dr Tim Mitchell, CEO of Sareum Holdings plc, said: “The progress being made by Sierra Oncology, our licence partner for the potentially best-in-class Chk1 inhibitor SRA737, has been extremely encouraging and highlights its broad therapeutic potential across multiple cancer indications. We look forward to initial results from the innovative clinical trials expected in the fourth quarter of 2018 and further programme updates during the year.

“Our internal preclinical programmes also continue to advance, and we are particularly pleased that distinct TYK2 inhibitors have emerged in each of the cancer and autoimmune disease areas and are now progressing towards formal preclinical development.

“The new funds raised in November are supporting our internal development activities, which we see as key to generating value for shareholders. We look forward to reporting further progress across our business and portfolio during 2018.”

The full report is available as a pdf document: Financial Results for the Six Months Ended 31/12/2017

About Sareum

Sareum is a specialist drug discovery and development company delivering targeted small molecule therapeutics, focusing on cancer and autoimmune disease, and generating value through licensing them to international pharmaceutical and biotechnology companies at the preclinical or early clinical trials stage.

Its most advanced programme, SRA737, is a novel Checkpoint kinase 1 (Chk1) inhibitor licensed to NASDAQ-listed Sierra Oncology and in Phase 1/2 clinical trials targeting a range of advanced cancers. The key role of Chk1 in cancer cell replication and DNA damage repair suggests that SRA737 may have broad application as a targeted monotherapy and in combination with other oncology and immuno-oncology drugs in genetically defined patients.

Sareum is also advancing programmes to develop novel tyrosine kinase 2 (TYK2) inhibitors in autoimmune diseases and cancers, and Aurora+FLT3 inhibitors in haematological cancers, which are in the candidate selection and IND-enabling preclinical stages.

The Company’s drug discovery technology platform (SKIL® – Sareum Kinase Inhibitor Library) has the potential to generate drug research programmes against other kinase targets.

Sareum Holdings plc is quoted on the Alternative Investment Market (AIM) of the London Stock Exchange, trading under the ticker SAR. For further information, please visit www.sareum.co.uk.