Evaluation of BGJ398, a Fibroblast Growth Factor Receptor 1-3 Kinase Inhibitor, in Patients With Advanced Solid Tumors Harboring Genetic Alterations in Fibroblast Growth Factor Receptors: Results of a Global Phase I, Dose-Escalation and Dose-Expansion Study

Abstract

Purpose This two-part, first-in-human study was initiated in patients with advanced solid tumors harboring genetic alterations in fibroblast growth factor receptors (FGFRs) to determine the maximum tolerated dose (MTD), the recommended phase II dose (RP2D), and the schedule, safety, pharmacokinetics, pharmacodynamics, and antitumor activity of oral BGJ398, a selective FGFR1-3 tyrosine kinase inhibitor. Patients and Methods Adult patients were treated with escalating dosages of BGJ398 5 to 150 mg once daily or 50 mg twice daily continuously in 28-day cycles. During expansion at the MTD, patients with FGFR1-amplified squamous cell non-small-cell lung cancer (sqNSCLC; arm 1) or other solid tumors with FGFR genetic alterations (mutations/amplifications/fusions) received BGJ398 daily on a continuous schedule (arm 2), or on a 3-weeks-on/1-week-off schedule (arm 3). Results Data in 132 patients from the escalation and expansion arms are reported (May 15, 2015, cutoff). The MTD, 125 mg daily, was determined on the basis of dose-limiting toxicities in four patients (100 mg, grade 3 aminotransferase elevations [n = 1]; 125 mg, hyperphosphatemia [n = 1]; 150 mg, grade 1 corneal toxicity [n = 1] and grade 3 aminotransferase elevations [n = 1]). Common adverse events in patients treated at the MTD (n = 57) included hyperphosphatemia (82.5%), constipation (50.9%), decreased appetite (45.6%), and stomatitis (45.6%). A similar safety profile was observed using the 3-weeks-on/1-week-off schedule (RP2D). However, adverse event-related dose adjustments/interruptions were less frequent with the 3-weeks-on/1-week-off (50.0%) versus the continuous (73.7%) schedule. Antitumor activity (seven partial responses [six confirmed]) was demonstrated with BGJ398 doses ≥ 100 mg in patients with FGFR1-amplified sqNSCLC and FGFR3-mutant bladder/urothelial cancer. Conclusion BGJ398 at the MTD/RP2D had a tolerable and manageable safety profile and showed antitumor activity in several tumor types, including FGFR1-amplified sqNSCLC and FGFR3-mutant bladder/urothelial cancers.

Fig 1.

Study scheme. DLT, dose-limiting toxicity; MTD, maximum tolerated dose; PK, pharmacokinetics; RP2D, recommended phase II dose. BID, twice daily; QD, once daily.

Fig 2.

Pharmacokinetics of BGJ398. AUC, area under the plasma concentration-time curve; inf, infinity; QD, once daily; SD, standard deviation.

Fig 3.

Waterfall plots of best change from baseline in the size of target lesions for patients treated at ≥ 100 mg BGJ398.

Fig 4.

Response and duration of exposure in patients treated at BGJ398 doses ≥ 100 mg. Among the patients with other cancer types were five patients with cholangiocarcinoma (green bars). PR, partial response.

Fig A1.

Pharmacodynamics of BGJ398. Percentage change from baseline in (A) phosphate and (B) FGF23 plasma levels on cycle 1 day 15 by dose. Median values are shown as box plots. BID, twice daily; FGF, fibroblast growth factor; QD, once daily.