Hutchmed launches development programme for next-gen therapy platform
By Josh White
Date: Wednesday 17 Dec 2025
(Sharecast News) - Hutchmed said on Wednesday that it has initiated a global phase one clinical development programme for HMPL-A251, marking the first clinical-stage candidate from its next-generation Antibody-Targeted Therapy Conjugate platform.
The AIM-traded firm said the first-in-human phase one/2a, open-label, multicentre study was evaluating HMPL-A251 as a monotherapy in adult patients with unresectable, advanced or metastatic HER2-expressing solid tumours.
Study sites are located in the United States and China, with the first patient having received the initial dose on 16 December in China.
The trial comprises a phase one dose-escalation stage and a phase 2a dose-expansion and optimisation stage, with the initial focus on assessing safety, tolerability and defining the maximum tolerated and recommended doses.
HMPL-A251 is a first-in-class PI3K/PIKK-HER2 ATTC, combining a highly selective PI3K/PIKK inhibitor payload with a humanised anti-HER2 IgG1 antibody via a cleavable linker.
Hutchmed said the design was intended to deliver targeted pathway inhibition directly to HER2-expressing tumour cells, potentially overcoming the systemic toxicity and narrow therapeutic index that have historically limited PI3K/PIKK inhibitors.
Secondary endpoints of the study include preliminary anti-tumour activity, pharmacokinetics and immunogenicity.
Hutchmed said preclinical data for HMPL-A251, presented earlier this year, supported the translational potential of the ATTC platform and its broader application across a family of future drug candidates.
The company said the ATTC platform represented a next-generation approach to precision oncology, combining monoclonal antibodies with proprietary small-molecule inhibitor payloads to deliver dual mechanisms of action while aiming to reduce off-tumour toxicity and improve long-term tolerability.
At the close on Wednesday, shares in Hutchmed China were up 1% at 202p.
Reporting by Josh White for Sharecast.com.
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