Regorafenib in combination with paclitaxel for beyond first-line treatment of advanced esophagogastric cancer (REPEAT): A phase Ib trial with expansion cohort

Abstract

Background: Advanced esophagogastric cancer (EGC) has a dismal prognosis of less than one year. Survival has improved with second line therapies, such as the combination of the angiogenesis inhibitor Ramucirumab and Paclitaxel (PTX). Monotherapy with Regorafenib (Reg), a multikinase inhibitor of angiogenic, stromal, and oncogenic kinases, demonstrated an improved progression-free survival (PFS) in advanced gastric cancer. In the REPEAT trial, we assessed the tolerability of Reg in combination with PTX for beyond first-line treatment of patients (pts) with advanced EGC. Method(s): Pts with metastatic EGC who progressed after first-line treatment, received PTX 80 mg/m2 i.v. on day 1, 8, and 15 of a 28-day cycle, and 120 mg Reg on day 1-21 of a 28-day cycle, as determined in phase Ib. Toxicity was assessed using CTCAE version 4, and Kaplan-Meier estimates of overall survival (OS) and PFS were done. In tumour biopsies, the effect of Reg on PTX uptake and Reg targets will be assessed, and the effect of Reg on PTX pharmacokinetics will be evaluated. Result(s): Reg 120 mg on day 1-21 combined with PTX was well tolerated in the Ib phase (N=14), and 33 pts were enrolled in the expansion cohort (total 47 pts, 81% received 120 mg). The majority of pts received treatment as second-line (60%); the remainder as third line or beyond. Most common grade 1/2 toxicities included fatigue (11%), peripheral sensory neuropathy (9%), diarrhea (5%), and alopecia (5%). Hypertension (10%), diarrhea (7%), and peripheral sensory neuropathy (5%) were the most common grade 3/4 toxicities. Median number of cycles was 4 (IQR 2-6), with 5 pts still on treatment (median follow-up 6.9 months). Best responses achieved were partial response (26%), stable disease (51%), and progressive disease (15%), with 4 patients not evaluable. Reasons for treatment discontinuation were progression (n=36), toxicity (n=5), or patient decision (n=1). Median PFS and median OS were 4.1 months and 7.8 months, respectively. Conclusion(s): The combined treatment of Reg with PTX is tolerable and shows promising effects on survival in beyond first-line treatment of advanced EGC. PK analyses and biomarker analyses on biopsies of metastatic lesions are ongoing.