Shanghai Henlius Biotech, Inc. (Henlius) has initiated clinical evaluation of its internally developed KAT6A/B small-molecule inhibitor HLX97, dosing the first patient in a multicentre, open-label Phase 1 study targeting advanced or metastatic solid tumours in mainland China (excluding Hong Kong, Macau and Taiwan).
The trial design incorporates two sequential parts. Part 1 is a dose-escalation segment with monotherapy (Part 1A) across five dose levels (1.0 mg–15.0 mg, orally, once daily in 28-day cycles) and combination therapy (Part 1B) pairing HLX97 with fulvestrant in hormone-receptor-positive, HER2-negative breast cancer. Primary endpoints for Part 1 are dose-limiting toxicities and maximum tolerated dose determination. Part 2 is a dose-expansion cohort enrolling the same breast-cancer population in three arms: two HLX97-plus-fulvestrant regimens and a fulvestrant monotherapy control. Key efficacy endpoints in Part 2 include objective response rate and progression-free survival, alongside selection of a recommended Phase 2 dose.
HLX97 targets lysine acetyltransferases 6A and 6B, enzymes implicated in tumourigenesis and endocrine resistance in breast cancer. Pre-clinical data demonstrated inhibition of KAT6A/B activity with favourable safety and anti-tumour profiles. Regulatory clearance for this Phase 1 study was granted by China’s National Medical Products Administration in March 2026.
Globally, no KAT6A/B inhibitor has yet reached the market, positioning HLX97 as a potential first-in-class therapy. Henlius emphasises that development outcomes remain uncertain; investors are urged to exercise caution when dealing in the company’s shares.
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