Dear Shareholders,
Following my previous letter at the start of the year, I wanted to provide a further update as we continue to make good progress across the business.
Last week, we were pleased to announce the restart of the Phase 2-enabling toxicology programme for our lead asset, SDC-1801. This represents an important step forward for the programme after the discontinuation of the earlier study last year.
Ahead of restarting the programme, we completed preliminary pharmacokinetic work to evaluate tolerability and exposure across a range of formulations. This work allowed us to select a vehicle with appropriate precedent for long-term studies and provided confidence to move forward. We have now appointed a leading global contract research organisation (“CRO”) with extensive experience in long-term toxicology studies to conduct the programme; we worked closely with the CRO to determine the optimum formulation for these studies.
The toxicology studies are being carried out using our existing cash resources and the previously manufactured toxicology batch of SDC-1801. The dosing phase is expected to complete in mid-2026, with the full Phase 2-enabling regulatory package anticipated to be complete by the end of the year. Together with ongoing CMC and formulation development activities, this work is intended to position SDC-1801 for Phase 2 clinical development.
As a reminder, the Phase 1 clinical study of SDC-1801 in healthy volunteers met its primary objectives and demonstrated a favourable safety and tolerability profile, with pharmacokinetics supporting once-daily dosing and dose-responsive biomarker reductions. The full dataset has been submitted to an academic journal and is undergoing peer review.
Shareholders who follow the TYK2 space will have noted continued activity across the class. Bristol Myers Squibb’s selective TYK2 inhibitor, Sotyktu (deucravacitinib), which is already approved for plaque psoriasis, is currently under FDA review for psoriatic arthritis, with a decision expected in the coming weeks. Meanwhile, brepocitinib – the dual TYK2/JAK1 inhibitor being developed by Priovant/Roivant – has had an active start to 2026, with an NDA now submitted to the FDA for dermatomyositis following positive Phase 3 data, and positive Phase 2 results reported earlier this month in cutaneous sarcoidosis. This continued momentum across the TYK2/JAK1 field is very encouraging for Sareum, as we further validate the mechanism and the commercial opportunity for well-differentiated inhibitors in this class.
With the toxicology programme now underway and formulation work progressing, our attention is increasingly turning to Phase 2 planning. Psoriasis remains our planned initial indication, and we are giving careful thought to study design, dose selection and regulatory strategy to ensure we are well prepared to move quickly once the enabling package is complete.
Looking ahead, we will shortly be reporting our Half Year results, which will provide a full update on our financial position and progress across the portfolio. We will also be attending BIO-Europe Spring in Lisbon from 23–25 March, one of the key partnering conferences in the European biotech calendar, where we look forward to continuing discussions with potential partners for our pipeline assets.
We appreciate the continued engagement and support of our shareholders and remain committed to maintaining open and regular communication.
Dr Stephen Parker,
Executive Chairman,
Sareum Holdings plc