Shanghai, China – March 5, 2026 – Shanghai Henlius Biotech, Inc. (2696.HK) today announced that the NMPA has approved the IND application for HLX97, a novel oral small molecule inhibitor targeting Lysine Acetyltransferase 6A/B (KAT6A/B) independently developed by the company, for the treatment of advanced or metastatic solid tumors. It is expected to provide a new therapeutic option for patients with breast cancer and other solid tumors who have progressed on standard therapies.
A Potential Best-in-Class KAT6A/B Inhibitor for Later-line Treatment of Solid Tumors
KAT6A (Lysine Acetyltransferase 6A) and its paralog KAT6B (Lysine Acetyltransferase 6B) are histone lysine acetyltransferases (HATs) belonging to the MYST family. Together with other chromatin-associated proteins, they acetylates lysine residues on histone H3 and plays a key role in the development and drug resistance of various tumors. Preclinical and clinical studies demonstrate that, amplification or overexpression of KAT6A is closely associated with endocrine therapy in heavily pretreated patients with estrogen receptor-positive(ER+)/human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer. In addition, dysregulation of KAT6A/B has been observed in various solid tumors, including ovarian, cervical, colorectal, prostate, lung cancers, and glioma1-3, underscoring the broad therapeutic potential of KAT6A/B inhibitors in oncology.
HLX97 is a novel, oral KAT6A/B inhibitor with best-in-class potential. By precisely inhibiting KAT6A/B activity, HLX97 inhibits tumor cell proliferationand induces apoptosis. It is characterized by a "fast-on/fast-off" pharmacokinetic profile and high selectivity, designed to maximize anti-tumor efficacy while minimizing hematologic toxicity. Nonclinical studies have demonstrated that HLX97 exhibits potent anti-tumor activity and a favorable safety profile. In comparisons with PF-07248144, HLX97 exhibited superior enzymatic inhibition and enhanced selectivity against KAT5/7/8. Notably, in preclinical studies, HLX97 demonstrated anti-tumor activity comparable or superior to the reference molecule at lower doses. Furthermore, at similar efficacy levels, HLX97 induced significantly less hematological toxicity, suggesting a potentially broader therapeutic window in the clinical setting. Additionally, HLX97 shows favorable ADME characteristics, such as high oral bioavailability and excellent pharmacokinetics 4-5.
Breast cancer is the second most common cancer globally and ranks as both the most frequently diagnosed malignancy and the leading cause of cancer death among women. Among its subtypes, estrogen receptor-positive (ER+) breast cancer is the most prevalent, accounting for approximately 70% of all breast cancer cases 6. Treatment strategies for ER+ breast cancer include inhibition of estrogen production and interventions directly targeting the ER, collectively referred to as endocrine therapy. Although endocrine therapy has significantly reduced recurrence and mortality rates in breast cancer, de novo and acquired resistance remain major clinical challenges. Given the established role of KAT6A amplification/overexpression in driving endocrine therapy resistance in breast cancer, inhibition of KAT6A/B activity represents a promising strategy to fulfill this umet medical needs 7-9.
Building a Full Continuum Care Ecosystem for Breast Cancer
The IND approval of HLX97 marks a key milestone in the establishment of Henlius’ fully integrated small-molecule drug R&D capabilities. Building on this, the company is executing a differentiated strategy across its pipeline—pursuing both innovation on established targets and moves into emerging ones—to fully harness the potential of its integrated small-molecule and biologics platforms. Henlius has built a comprehensive pipeline covering the full continuum of breast cancer care through internal innovation and strategic collaborations. Its marketed products include HANQUYOU (trade name: HERCESSI™ in the U.S., Zercepac® in Europe), a trastuzumab biosimilar approved in over 50 countries and regions including China, the U.S., and Europe; POHERDY®, the first pertuzumab biosimilar approved in the U.S.; HANNAIJIA (neratinib), an extended adjuvant therapy for early-stage breast cancer, and CDK4/6 inhibitor FUTUONING (fovinaciclib). Meanwhile, Henlius is advancing next-generation molecules such as novel epitope anti-HER2 antibody HLX22, oral selective estrogen receptor modulator (SERM) lasofoxifene (HLX78), KAT6A/B inhibitor HLX97, LIV-1-targeting ADC HLX41, HER2×HER2 bispecific epitope ADC HLX49 and HER2 ADC HLX87 through its robust innovation platforms and collaborative R&D. Building on this foundation, Henlius remains committed to advancing monotherapies and combination regimens across all breast cancer subtypes, enhancing therapeutic value through strengthened pipeline synergies.
Looking ahead, Henlius will continue to adhere to its "patient-centric" R&D philosophy. Leveraging its integrated, platform‑based innovation engine, the company is committed to accelerating the development of a differentiated, globally competitive innovative pipeline, striving to provide more accessible and effective treatment options for patients worldwide.
References
1. Chen J, et al. Mutations of Chromatin Structure Regulating Genes in Human Malignancies. Curr Protein Pept. Sci. 2016;17(5):411-437.
2. Partynska A, et al. The Expression of Histone Acetyltransferase KAT6A in Non-small Cell Lung Cancer. Anticancer Res. 2022;42(12):5731-5741.
3. Lv D, et al. Histone Acetyltransferase KAT6A Upregulates PI3K/AKT Signaling through TRIM24 Binding. Cancer Res. 2017;77(22):6190-6201.
4. Liu R, et al. Abstract 6976: Identification of novel KAT6A/B inhibitors with enhanced antitumor activity and reduced hematologic toxicity. Cancer Res (2025) 85 (8_Supplement_1): 6976. AACR Annual Meeting 2025.
5. 2026年第44届摩根大通医疗健康年会复宏汉霖投资者推介材料
6. Nolan E, et al. Deciphering breast cancer: from biology to the clinic. Cell. 2023;186(8):1708-1728.
7. Sharma S, et al. Discovery of a highly potent, selective, orally bioavailable inhibitor of KAT6A/B histone acetyltransferases with efficacy against KAT6A-high ER+ breast cancer. Cell Chem Biol. 2023;30(10):1191-1210.e20.
8. Yu L, et al. Identification of MYST3 as a novel epigenetic activator of ERα frequently amplified in breast cancer. Oncogene. 2017;36(20):2910-2918.
9. Yu L, et al. Identification of MYST3 as a novel epigenetic activator of ERα frequently amplified in breast cancer. Oncogene. 2017;36(20):2910-2918. doi:10.1038/onc.2016.433