Initiation of Toxicology Studies for SDC-1801

Cambridge, UK, 29 May 2025 - Sareum Holdings plc (AIM: SAR), a clinical-stage biotechnology company developing next-generation kinase inhibitors for autoimmune disease and cancer, is pleased to announce the initiation of a programme of toxicology studies for its lead TYK2/JAK1 inhibitor, SDC-1801.

The studies, designed to support longer-term dosing of SDC-1801, will investigate the general toxicology and potential of SDC-1801 to interact with other drugs. These are key regulatory requirements ahead of the planned Phase 2 clinical development programme, which is expected to focus initially on psoriasis. This marks an important step in advancing Sareum's autoimmune pipeline, following the successful completion of its Phase 1 clinical trial in healthy volunteers, which demonstrated a favourable safety and pharmacokinetic profile.

The toxicology studies required to prepare for Phase 2 clinical trials are being conducted at an established Contract Research Organisation and are expected to complete in Q4 2025. Sareum continues to make progress, in parallel, with its manufacturing and formulation optimisation activities to support the next stages of development.

Dr Stephen Parker, Executive Chairman of Sareum, commented: "We are pleased to have initiated this important package of toxicology studies for SDC-1801, which represents a significant milestone in the regulatory pathway towards Phase 2 trials. This progress reflects the encouraging data generated in our Phase 1 trial and our confidence in the potential of SDC-1801 as a differentiated treatment for autoimmune diseases. We look forward to providing further updates as we continue to advance this promising candidate."