16 December 2025, Abbisko Therapeutics Co., Ltd. ("Abbisko Therapeutics" hereafter, HKEX code: 02256.HK) today announced that the first patient has been successfully dosed in the Phase II clinical study evaluating ABSK061, a highly selective small-molecule FGFR2/3 inhibitor, in children ages 3 to 12 with achondroplasia (ACH).

ACH is a rare autosomal genetic disorder that causes severe growth and developmental impairments. Research has shown that the pathogenesis of ACH is driven by aberrant activation of the fibroblast growth factor receptor 3 (FGFR3) caused by FGFR3 gene mutations, which suppress normal endochondral ossification¹. Targeted inhibitors offer the potential to deliver more precise and effective treatment options for ACH patients.

ABSK061, independently developed by Abbisko Therapeutics, is a highly potent and selective small-molecule FGFR2/3 inhibitor. It has demonstrated robust target inhibitory activity, favorable pharmacokinetic properties, and a promising safety profile in preclinical studies. Its oral administration offers significant advantages in terms of  convenience and treatment compliance—particularly for pediatric patients—and positions ABSK061 as a potentially valuable therapeutic candidate for children and adolescents with ACH. 

The first-patient dosing was completed as part of an open-label Phase II clinical study designed to comprehensively evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of ABSK061 in children ages 3 to 12 with ACH. The study received Investigational New Drug (IND) clearance from the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA) in March 2025.

About ABSK061

ABSK061 is a novel, orally bioavailable, highly potent and selective small molecule inhibitor of FGFR2 and FGFR3 independently discovered and wholly-owned by Abbisko Therapeutics. It is the first FGFR2/3 inhibitor to enter clinical trials globally. First-generation pan-FGFR inhibitors demonstrated clinical efficacy in multiple tumors carrying FGFR2/3 variants and have steadily gained regulatory approval globally. However, the therapeutic window of pan-FGFRs and their clinical efficacy have been limited by side effects associated with FGFR1 inhibition. By reducing FGFR1 activity while maintaining potency against FGFR2 and FGFR3, ABSK061 is expected to achieve a wider therapeutic window with improved clinical efficacy as a new-generation of FGFR inhibitors.

About Abbisko Therapeutics

Founded in April 2016, Abbisko Therapeutics Co., Ltd. (HKEX: 02256.HK), is an oncology-focused biopharmaceutical company based in Shanghai that is dedicated to the discovery and development of innovative medicines to treat unmet medical needs in China and globally. The Company was established by a group of seasoned drug hunters with rich research & development and managerial expertise from top multinational pharmaceutical companies. Since its founding, Abbisko Therapeutics has built an extensive pipeline of innovative programs focused on precision oncology and immuno-oncology.

Please visit www.abbisko.com for more information.

Reference

[1] Savarirayan R, et al. International Consensus Statement on the diagnosis, multidisciplinary management and lifelong care of individuals with achondroplasia. Nat Rev Endocrinol. 2022 Mar;18(3):173-189.