HENLIUS (02696) has announced that the first patient in China (excluding Hong Kong, Macao, and Taiwan) has been dosed in a Phase 1 clinical study of its self-developed HLX97, a KAT6A/B small molecule inhibitor, for patients with advanced or metastatic solid tumors.
This study is a multi-center, open-label Phase 1 trial designed to evaluate the safety, tolerability, pharmacokinetic (PK) profile, and preliminary anti-tumor efficacy of HLX97 in patients with advanced or metastatic solid tumors. The research is divided into two parts. Part 1 is the dose escalation phase, consisting of monotherapy dose escalation (Part 1A) and combination therapy dose escalation (Part 1B). Part 2 is the dose expansion phase.
Part 1A monotherapy escalation will be conducted in patients with advanced/metastatic solid tumors, exploring five dose levels from 1.0mg to 15.0mg. HLX97 will be administered orally once daily on days 1-28 of each 4-week cycle. Part 1B combination therapy will explore 2 to 3 dose levels of HLX97 combined with fulvestrant in patients with HR-positive, HER2-negative locally advanced or metastatic breast cancer. Part 2 will be conducted in the same patient population, featuring two combination therapy groups with different doses of HLX97 plus fulvestrant and one fulvestrant monotherapy control group.
The primary endpoints for Part 1 are to assess the incidence of dose-limiting toxicities (DLT) and to determine the maximum tolerated dose (MTD) for HLX97 monotherapy and its combination with fulvestrant. The primary endpoints for Part 2 are the objective response rate (ORR) and progression-free survival (PFS) as assessed by investigators per RECIST v1.1, as well as the recommended Phase 2 dose (RP2D) for the HLX97 and fulvestrant combination. Secondary endpoints include the safety and PK parameters of HLX97 both as monotherapy and in combination, other efficacy measures (such as duration of response (DOR), disease control rate (DCR), overall survival (OS)), and exploratory pharmacodynamic and predictive biomarker analyses.
HLX97 is a self-developed lysine acetyltransferase 6A/B (KAT6A/B) small molecule inhibitor intended for the treatment of advanced/metastatic solid tumors. KAT6A and its paralog KAT6B function as histone lysine acetyltransferases. They participate, along with other chromatin-associated proteins, in acetylating lysine residues on histone H3, thereby playing an oncogenic role in various tumor types. In breast cancer, amplification/overexpression of the KAT6A gene has been closely linked to the development of endocrine therapy resistance. Consequently, inhibiting KAT6 is a promising strategy to overcome such resistance. Preclinical studies have shown that HLX97 effectively inhibits KAT6A/B activity, demonstrating favorable anti-tumor efficacy and safety profiles.
In March 2026, the Investigational New Drug (IND) application for the Phase 1 clinical trial of HLX97 in patients with advanced/metastatic solid tumors was approved by the National Medical Products Administration (NMPA). As of the date of this announcement, no KAT6A/B small molecule inhibitors have been approved for marketing globally.
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