1. Exposure–response analyses of erdafitinib in patients with locally advanced or metastatic urothelial carcinoma
- Author
-
Anne-Gaëlle Dosne, Elodie Valade, Nele Goeyvaerts, Peter De Porre, Anjali Avadhani, Anne O’Hagan, Lilian Y. Li, Daniele Ouellet, and Juan Jose Perez Ruixo
- Subjects
Male ,Pharmacology ,Carcinoma, Transitional Cell ,Cancer Research ,Dose-Response Relationship, Drug ,Middle Aged ,Toxicology ,Receptors, Fibroblast Growth Factor ,Progression-Free Survival ,Survival Rate ,Urinary Bladder Neoplasms ,Oncology ,Quinoxalines ,Humans ,Pyrazoles ,Female ,Pharmacology (medical) ,Protein Kinase Inhibitors ,Aged - Abstract
Background Exposure–response analyses were conducted to explore the relationship between selected efficacy and safety endpoints and serum phosphate (PO4) concentrations, a potential biomarker of efficacy and safety, in locally advanced or metastatic urothelial carcinoma patients with FGFR alterations treated with erdafitinib. Methods Data from two dosing regimens of erdafitinib in a phase 2 study (NCT02365597), 6 and 8-mg/day with provision for pharmacodynamically guided titration per serum PO4 levels, were analyzed using Cox proportional hazard or logistic regression models. Efficacy endpoints were overall survival (OS), progression-free survival (PFS), and objective response rate (ORR). Safety endpoints were adverse events typical for FGFR inhibitors. Results Exposure-efficacy analyses on 156 patients (6-mg = 68; 8-mg = 88) showed that patients with higher serum PO4 levels within the first 6 weeks showed better OS (hazard ratio 0.57 [95% CI 0.46–0.72] per mg/dL of PO4; p = 0.01), PFS (hazard ratio 0.80 [0.67–0.94] per mg/dL of PO4; p = 0.01), and ORR (odds ratio 1.38 [1.02–1.86] per mg/dL of PO4; p = 0.04). Exposure-safety analyses on 177 patients (6-mg = 78; 8-mg = 99) showed that the incidence of selected adverse events associated with on-target off-tumor effects significantly rose with higher PO4. Conclusions The exploratory relationship between serum PO4 levels and efficacy/safety outcomes supported the use of pharmacodynamically guided dose titration to optimize erdafitinib’s therapeutic benefit/risk ratio. Clinical trial registration number NCT02365597.
- Published
- 2022
- Full Text
- View/download PDF