Dear Shareholders,

Thank you to everyone who joined our recent Investor Meet Company (IMC) session following the announcement of our results for the six months ended 31 December 2025. As always, I value the thoughtful questions and the opportunity to discuss our progress directly with shareholders.

This discussion has prompted me to think about the continued exciting momentum across the TYK2 field, which has become an important backdrop for Sareum. There has been increasing attention on dual TYK2/JAK1 inhibitors, in particular Roivant’s brepocitinib, which shares the same target profile as SDC-1801. This is expected to receive its first approval this year for dermatomyositis, a rare autoimmune condition. The programme has been widely described as one of the most valuable assets in the Roivant portfolio and is generating significant interest across the sector. This external validation strengthens our conviction in the potential for effective small molecules within this class and provides helpful context as we advance our own programme.

Developments like this continue to reinforce the growing confidence in the mechanism and the commercial potential of well-differentiated inhibitors in this class. For Sareum, it provides additional impetus for the opportunity we see with SDC-1801 as we advance the programme and continue to engage in business development discussions. The clear scientific and commercial interest surrounding more selective TYK2 driven therapies reflects the desire for improved safety profiles while maintaining meaningful efficacy, which we are trying to achieve with our assets. Together these emerging trends across the industry underscore the growing recognition of TYK2‑based approaches and the potential for differentiated molecules to play a meaningful role in next generation immunology and inflammation therapies.

Sareum has restarted the Phase 2-enabling toxicology programme for SDC-1801, following the earlier discontinuation of the previous study. With dosing now underway and formulation work progressing alongside it, we continue to move the programme forward towards Phase 2 clinical development.

At the same time, we are continuing to advance the broader portfolio. Work on SDC-1802 has reached an important point following the completion of translational studies, and we are now considering the best route to progress the programme through partnership. In oncology, we remain active in exploring opportunities for SRA737, while our TYK2 neuroscience collaboration with Receptor.AI continues to generate encouraging early data as we seek to identify molecules suitable for neuro-inflammatory diseases.

The discussions during the IMC presentation reinforced how closely many of you follow developments across the TYK2 field and our own programmes. The continued momentum we are seeing around this class of inhibitors remains encouraging and strengthens our conviction in the opportunity for well-differentiated molecules such as SDC-1801.

Looking ahead, our priorities remain clear. Over the coming months we will continue progressing the ongoing toxicology programme for SDC-1801, advancing our discovery collaboration and supporting partnering discussions across the portfolio. With several important milestones ahead, we remain focused on delivering steady progress while managing the Company’s resources carefully.

Thank you again for your continued engagement and support. I look forward to updating you further as the year progresses.

Dr Stephen Parker,
Executive Chairman,
Sareum Holdings plc