Shanghai, China, September 21, 2026
Abbisko Therapeutics has announced positive preliminary results from a Phase 2 clinical study evaluating lavengratinib (ABSK061) in children with achondroplasia (ACH), a genetic skeletal disorder that affects bone growth. The investigational therapy is a selective, orally available small-molecule inhibitor of FGFR2 and FGFR3 and is being developed as a potential treatment for children with achondroplasia. In the first and lowest dose cohort, children aged six years and older who received lavengratinib at 0.064 mg/kg once daily for 27 weeks achieved a mean improvement of +2.4 cm/year in annualized height velocity (AHV) compared with baseline, while the reported responder rate reached 100%. Abbisko also reported that lavengratinib was well tolerated in the participants evaluated to date, with no serious adverse events or treatment discontinuations caused by adverse events reported.
Phase 2 Study Shows Early Growth Signals
The ABSK061-202 Phase 2 study is a multicenter, open-label, dose-escalation clinical trial designed to evaluate the safety and efficacy of lavengratinib in children between three and 12 years of age with achondroplasia. Participants are planned to receive once-daily oral treatment for a total duration of 78 weeks. According to Abbisko, all seven children aged six to 12 years enrolled in the first dose cohort had completed approximately six months of treatment and demonstrated encouraging preliminary findings. At Week 27, the seven participants showed a mean improvement of 2.4 cm per year in annualized height velocity from baseline, with all seven meeting the company’s predefined responder criterion. Abbisko defines a responder as a participant achieving at least a 25% improvement in annualized height velocity compared with baseline. Participants enrolled in higher-dose cohorts remain under treatment, meaning the currently reported findings represent an early analysis from the ongoing Phase 2 program rather than final study results.
Lavengratinib Targets FGFR2 and FGFR3
Lavengratinib is designed to selectively inhibit FGFR2 and FGFR3, signaling pathways that play important roles in skeletal development. Abbisko is developing the molecule with the goal of maintaining activity against FGFR2 and FGFR3 while reducing activity against FGFR1, which the company believes could potentially improve the therapeutic window compared with earlier pan-FGFR inhibitors. The candidate is administered orally using Abbisko’s mini-tablet formulation, with tablets measuring less than three millimeters in diameter. The company says this formulation was developed to facilitate administration in children and can be given with food or drink. Lavengratinib has received both U.S. FDA Rare Pediatric Disease Designation and Orphan Drug Designation for achondroplasia, while its Phase 2 clinical development remains ongoing.
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Safety Monitoring and Next Development Steps
Safety remains an important component of the ongoing pediatric study. Abbisko reported that the first three dose cohorts have completed their preliminary safety evaluation, with no safety concerns identified to date. No serious adverse events or treatment discontinuations because of adverse events have been reported in the available data. The company also stated that no specific safety signals associated with FGFR pathway inhibition have been observed so far, including adverse events associated with FGFR1 or FGFR2 inhibition such as hyperphosphatemia and corneal toxicity. However, the study is still ongoing, and longer-term safety and efficacy data will be needed to further characterize lavengratinib’s clinical profile. Abbisko expects additional six-month efficacy and safety results by the end of 2026, which could provide further information on the candidate’s potential in children with achondroplasia.
Source: Abbisko Therapeutics press release
