Pharmacokinetics, pharmacodynamics and efficacy of pemigatinib (a selective inhibitor of fibroblast growth factor receptor 1–3) monotherapy in Chinese patients with advanced solid tumors: a phase i clinical trial

Abstract Pemigatinib is a selective fibroblast growth factor receptor (FGFR)1–3 inhibitor and has demonstrated acceptable tolerability and clinical activity in advanced solid tumors in Western population. This phase I trial evaluated pharmacokinetics/pharmacodynamics (PK/PD) characteristics, preliminary safety and efficacy of pemigatinib in Chinese patients with advanced, solid tumors. Patients with unresectable advanced or metastatic solid tumors bearing FGF/FGFR1-3 alterations received oral pemigatinib at 13.5 mg once daily (QD) on a 2-weeks-on/1-week-off schedule. The primary endpoint was PK/PD characteristics; secondary endpoints were safety and efficacy. Twelve patients were enrolled (median age: 61 years, 58.3% males). PK data demonstrated pemigatinib (13.5 mg QD) was rapidly absorbed with a geometric mean elimination half-life of 11.3 h. The geometric mean values of maximum serum concentration and area under the plasma concentration–time curve from 0 to 24 h at steady state were 215.1 nmol/L and 2636.9 h·nmol/L, respectively. The mean clearance adjusted by bioavailability at steady state was low (11.8 L/h), and the apparent oral volume of distribution was moderate (170.5 L). The PD marker, serum phosphate level, increased on days 8 and 15 of cycle 1 (mean: 2.25 mg/dL, CV% [percent coefficient of variation]: 31.3%) and decreased to baseline post 1 week off. Three (25.0%) patients experienced grade ≥ 3 treatment-emergent adverse events. Partial response was confirmed in one patient with FGFR1-mutant esophageal carcinoma and one with FGFR2-mutant cholagiocarcinoma. Pemigatinib had similar PK/PD characteristics to Western population and demonstrated an acceptable safety profile and potential anti-cancer benefit in Chinese patients with FGF/FGFR1-3 altered, advanced, solid tumor. (ClinicalTrials.gov: NCT04258527 [prospectively registered February 6, 2020]).