Completion of Dosing in Toxicology Programme

Cambridge, UK, 20 July 2026 -- Sareum Holdings plc (AIM: SAR), a clinical-stage biotechnology company developing next-generation kinase inhibitors for autoimmune disease and cancer, is pleased to announce that dosing has been completed in the Phase 2-enabling toxicology programme for SDC-1801, a selective oral TYK2/JAK1 inhibitor being developed as a potential treatment for a range of autoimmune diseases, with an initial focus on psoriasis.

Following the restart of the programme in February 2026, dosing has been completed in line with the Company's expectations. Using existing cash resources, Sareum is now analysing the resulting data and pursuing necessary chemistry, manufacturing and controls (CMC) and formulation development activities, aimed towards completion of the full Phase 2-enabling regulatory package by Q4 2026.

Dr John Reader, Chief Scientific Officer of Sareum, said: "The completion of dosing in this toxicology programme is an important milestone towards completing the full Phase 2-enabling regulatory package, building on the encouraging Phase 1 results, which showed a pharmacokinetic profile consistent with once-daily dosing and no safety concerns. We look forward to progressing the data analysis as we move closer to advancing SDC-1801 into the clinic for patients with autoimmune diseases."

Dr Stephen Parker, Executive Chairman of Sareum, added: "I am pleased to see the Phase 2-enabling toxicology programme completed on schedule, using existing cash resources and keeping us firmly on track towards our Phase 2-enabling milestones."