932PHyperphosphatemia due to erdafitinib (a pan-FGFR Inhibitor) and anti-tumour activity among patients (Pts) with advanced urothelial carcinoma (UC). (1st October 2019)

• Record Type: Journal Article
• Authors: Tagawa, S; Siefker-Radtke, A; Dosne, A -G; Zhong, B; Qi, K; Shalaby, W; O'Hagan, A; De Porre, P; Mahadevia, P; Loriot, Y
• Is Part Of: Annals of oncology. Volume 30(2019)Supplement 5
• Publication Date: 2019-10-01
• Subjects: Oncology -- Periodicals; 616.992
• DOI: 10.1093/annonc/mdz249.031
• Languages: English
• ISSNs: 0923-7534

Abstract

Abstract: Background: Erdafitinib (Erda), a pan-FGFR tyrosine kinase inhibitor, recently received accelerated approval by US FDA for treatment of post-platinum advanced UC pts with certain FGFR3 or 2 alterations. Erda induces dose dependent hyperphosphatemia via inhibition of PO4 excretion. Methods: Ph1 data and PK/PD modeling identified a serum PO4 level of ≥ 5.5 mg/dL as a PD target with acceptable tolerability. In a ph2 study (NCT02365597) pts started Erda at 8mg/day, serum PO4 was assessed every cycle, and Cycle 1 Day 14 (C1D14). Up-titration on C1D15 to 9mg/day occurred if serum PO4 was < 5.5 mg/dL and pts had no significant investigator assessed toxicity. Objective response rate (ORR) and disease control rate (DCR) were assessed by logistic regression analysis; progression free survival (PFS), and overall survival (OS) were calculated by Cox regression methods. Results: 99 patients started 8 mg Erda and 41% were up-titrated to 9 mg based on C1D14 PO4 levels. The ORR and DCR were higher (42.7% and 85.3%) when maximum PO4 levels were >5.5 mg/dL as compared to below (34.8% and 65.2%, respectively). Median OS and PFS were prolonged with levels >5.5 mg/dL as compared to below with hazard ratio of 0.35 (median not reached vs 6.7 months) and 0.68 (5.6 vs 3.8 months), respectively. Among patients that could not be up-titrated due to concurrent toxicities, ORR was 27.3% (n = 22; 95% CI- 8.7%, 45.9%) as compared to 48.8% (n = 41; 95% CI-33.5%, 64.1%) for patients who were up-titrated. Logistic regression analysis (ORR, DCR), and Cox regression (PFS, OS) showed that maximum phosphate levels positively correlated with ORR, DCR, PFS, and OS (Table). Conclusions: Hyperphosphatemia in Erda treated pts is associated with improved outcomes, supporting optimization of Erda dosing via uptitration based on serum PO4. Clinical trial identification: NCT02365597, February 19, 2015. Editorial acknowledgement: Himabindu Gutha (SIRO Clinpharm Pvt. Ltd.) writing assistance, Dr. Harry Ma (Janssen Research & Development, LLC) additional editorial support. Legal entity responsible for the study: Janssen Research & Development. Funding: Janssen Research & Development. Disclosure: S.T. Tagawa: Advisory / Consultancy: Medivation, Astellas Pharma, Dendreon, Janssen, Bayer, Genentech, Endocyte, Immunomedics, Karyopharm Therapeutics, AbbVie, Tolmar, QED, Amgen, Sanofi; Research grant / Funding (institution): Lily, Sanofi, Janssen, Astellas Pharma, Progenics, Millennium, Amgen, Bristol-Myers Squibb, Dendreon, Rexahn Pharmaceuticals, Bayer, Genentech, Newlink Genetics, Inovio Pharmaceuticals, AstraZeneca, Immunomedics, Novartis, AVEO, Boehringer Ingelheim, Merc; Travel / Accommodation / Expenses: Sanofi, Immunomedics, Amgen. A.O. Siefker-Radtke: Advisory / Consultancy: Janssen, Threshold Pharmaceuticals, Merck, National Comprehensive Cancer Network, Eisai, Genentech, Vertex, AstraZeneca, EMD Serono, Bristol-Myers Squibb; Speaker Bureau / Expert testimony: Genentech; Research grant / Funding (self): National Institutes of Health, Genentech, Janssen Pharmaceuticals, Millennium, Michael and Sherry Sutton Fund for Urothelial Cancer. A. Dosne: Full / Part-time employment: Janssen Research and Development. B. Zhong: Full / Part-time employment: Janssen Research and Development. W.S. Shalaby: Full / Part-time employment: Janssen Research and Development. A. O'Hagan: Full / Part-time employment: Janssen Research and Development. K. Qi: Stockholder / Stock options, Full / Parttime employment: Janssen Research and Development. P. De Porre: Full / Part-time employment: Janssen Research and Development. P. Mahadevia: Full / Part-time employment: Janssen Research and Development. Y. Loriot: Advisory / Consultancy: Astellas Oncology; AstraZeneca; Ipsen; Janssen; MSD; Roche; Sanofi; Research grant / Funding (self): Sanofi (Inst); Travel / Accommodation / Expenses: AstraZeneca; MSD; Roche. All other authors have declared no conflicts of interest.