19 March 2026, Abbisko Therapeutics Co., Ltd. ("Abbisko Therapeutics" hereafter, HKEX code: 02256) today announced that its independently developed, highly selective, oral small-molecule FGFR2/3 inhibitor ABSK061, has been granted Orphan Drug Designation (ODD) by the U.S. Food and Drug Administration (FDA) for the treatment of achondroplasia (ACH). This marks another significant milestone in the global development of ABSK061, following its recent Rare Pediatric Disease (RPD) designation from the FDA. The ODD is expected to strongly support the product's clinical development, regulatory filings, and commercialization in the United States.

Orphan Drug Designation is a key incentive established by the FDA to support the development and evaluation of innovative therapies for rare diseases. The ODD granted to ABSK061 not only underscores the FDA's recognition of its potential clinical value and need, but also provides several potential tangible benefits, including tax credits for qualified clinical trials, waiver of NDA/BLA user fees, and potential seven years of market exclusivity after approval—creating a strong foundation for future registration and commercialization.

Achondroplasia 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 ossification ¹. 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 is expected to significantly improve treatment convenience and compliance, particularly in pediatric populations, highlighting its potential as a therapeutic option for children and adolescents with ACH.

ABSK061 is currently being evaluated in a Phase II clinical trial in children aged 3–12 years with ACH. The study dosed its first patient in China in December 2025, and preliminary data are expected to be reported in the second half of 2026.

With both RPDD and ODD granted by the FDA, Abbisko Therapeutics will continue to accelerate the global clinical development and regulatory advancement of ABSK061, with the goal of bringing a safe and effective innovative treatment option to patients with ACH worldwide.

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.

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. ABSK061 for the treatment of achondroplasia has received both Rare Pediatric Disease Designation (RPDD) and Orphan Drug Designation (ODD) from the U.S. Food and Drug Administration (FDA), and its Phase II clinical trial is currently ongoing.

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.