A Qtc Study Of Cabazitaxel In Patients With Advanced Solid Tumors

257 Background: Cabazitaxel (Cbz) improves overall survival in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) after docetaxel failure, compared with mitoxantrone (HR 0.70; 95% CI 0.59-0.83; P < 0.0001). Following Cbz approval for the treatment of mCRPC, this study was undertaken to evaluate any effect of Cbz on the QTc interval.This prospective, multinational, open-label study ( NCT01087021 ) enrolled pts with advanced solid tumors (without other therapeutic options). Cbz 25 mg/m² IV was administered on Day 1 Q3W. QTc and other ECG intervals were assessed on Day 1 of Cycle 1. Triplicate ECGs were obtained from 12-lead Holter recordings and concomitant serial blood samples were collected for pharmacokinetic (PK) analysis. The primary endpoint was change from baseline in the corrected QTc interval (according to the Fridericia formula QTcF).A total of 96 pts were enrolled; 32 pts under the original protocol (6-h Holter) and 64 pts following protocol amendment 1, which extended ECG and PK monitoring (24-h Holter). Median age was 63 yrs (69.8% male), 30.5% and 57.9% of pts were ECOG PS 0 and 1 respectively; 33 pts (34.4%) had prostate cancer. Screening ECG was abnormal but not clinically significant in 39.6% of pts. The majority (n = 65) of pts received ≥ 3 treatment cycles; safety and ECG parameters were evaluated in 95 and 94 pts, respectively. In the 24-h Holter group (n = 63), the maximum least squares (LS) mean change from baseline in QTcF was 4.8 msec (90% CI 2.1-7.5), returning to baseline by 24 h. Similar results were observed in the overall population (n = 94). At Cmax, Cbz concentration had no effect on QTcF change from baseline; the mean (CV%) Cmax (n = 91) and AUC (n = 92) were 276 ng/ml (63%) and 1245 ng.h/ml (82%). The LS mean change from baseline in heart rate increased up to 24 h but remained < 10 beats per minute. The most common Grade 3/4 AEs were neutropenia (27.4%), febrile neutropenia (12.6%), fatigue (12.6%) and dehydration (5.3%). No Grade 3/4 cardiac AEs were reported. Of the 6 deaths reported, 1 (infection) was study drug related.Cbz had no significant effect on QTc interval in pts with advanced tumors. The Cbz safety profile is consistent with previous findings and with other taxane-based therapies.