28 Feb. 2024, Shanghai – Abbisko Therapeutics Co., Ltd. (Abbisko Therapeutics) presented the preliminary first-in-human results of its next-generation highly selective FGFR2/3 inhibitor ABSK061 in patients with advanced solid tumors during the 2024 European Society for Medical Oncology Targeted Anticancer Therapies Congress (ESMO TAT). The ESMO TAT was held in Paris, France from February 26 to 28, 2024.

As the first selective FGFR2/3 inhibitor entering human clinical trial globally, ABSK061 demonstrated exciting preliminary anti-tumor efficacy and lower hyperphosphatemia and other AEs compared to prior pan-FGFR inhibitors. Multiple FGFR2/3-altered patients, including lung, gastric and other cancer types, showed responses to ABSK061 treatment. These results also pave the road for future development of ABSK061 for treating achondroplasia and other diseases.

Abbisko presented the following details at the ESMO TAT:

Title: First-in-human Study of ABSK061, A Selective Fibroblast Growth Factor Receptor (FGFR) 2/3 Inhibitor for Treating Patients with Advanced Solid Tumors

Abstract: 450

Lecture Time：26 February 2024；16:37 - 16:45 CET

Category：advanced/metastatic solid tumors

Key Points:

This study is a global multi-center, open-label Phase I trial designed to evaluate the safety, tolerability, pharmacokinetics (PK), and anti-tumor activity of the FGFR2/3 inhibitor ABSK061 in patients with advanced solid tumors.

As of December 2023, a total of 29 patients were enrolled in the Phase Ia dose-escalation cohort, with a median age of 54 years old. The escalation began with an initial dose of 5mg BID and included 8 dose levels in total. No DLT (Dose-Limiting Toxicity) events were observed in dose-escalation part, and two dose cohorts, 75mg BID and 150mg QD, advanced to the RDE (Recommended Dose for Expansion) confirmation phase. The RDE confirmation cohorts are acitvely enrolling patients with FGFR-activating alterations to further confirm the efficacy.

Efficacy: Among 8 patients with solid tumors carrying FGFR-activating alterations (FGFR2 Fusion/Amplification or FGFR3 Fusion), as of the time of publication, 3 patients achieved confirmed partial response (cPR), resulting in an ORR (Objective Response Rate) of 37.5%; 3 patients achieved stable disease (SD), and 2 patients experienced disease progression (PD). The DCR (Disease Control Rate) was 75%.

Safety: Differentiated safety profile indicates high selectivity of FGFR2/3 inhibition. Most AEs are low grade and essentially reversible. Compared to pan-FGFR inhibitors, the incidence of hyperphosphatemia and diarrhea is lower, and the severity is reduced.

Conclusion: As the first highly selective FGFR2/3 inhibitor, ABSK061 has demonstrated promising efficacy during the dose-escalation phase, along with differentiated and tolerable safety profile compared to pan-FGFR inhibitors. These positive findings warrant further investigation.