Axitinib is a potent, selective, second-generation inhibitor of vascular endothelial growth factor receptors approved globally in advanced renal cell carcinoma (aRCC). A subset of patients (pts) treated with axitinib achieve long-term disease control. This analysis characterized the duration of treatment (DT) and clinical outcome of pts with aRCC who achieved a DT >18 months on axitinib therapy.
A retrospective analysis of data from 402 treatment-naïve pts with aRCC treated with axitinib in phase II (NCT00835978) or III (NCT00920816) clinical trials was conducted. Data on DT, objective response rate (ORR) per RECIST v1 criteria, and early tumor shrinkage (defined as ≥10% shrinkage at first scan) were compared between pts who had DT >18 months (longer DT) vs pts who had DT ≤ 18 months (shorter DT). Analysis was conducted to identify baseline characteristics associated with longer DT.
Of the 402 pts, 152 (37.8%) had longer DT and 250 (62.2%) had shorter DT. Overall, 119 (29.6%) had DT > 2 years, 71 (17.7%) had DT > 3 years, and 28 (7.0 %) had DT > 4 years. The median (range) DT was 34.7 (18.4–60.1) months for longer DT vs 6.5 (0.1–17.7) months for shorter DT. ORR was 75% for longer DT vs 24.4% for shorter DT (difference, 50.6%; 95% CI 41.9–59.3%; p 13 g/dL or female: > 11.5), no bone or liver metastases, and baseline tumor burden below overall median sum of longest diameter (96 mm) were associated with longer DT.
Among aRCC patients treated with first-line axitinib, a substantial proportion of patients remain on therapy for a prolonged period of time. Longer axitinib treatment duration (>18 months) is associated with increased ORR and increased frequency of early tumor shrinkage.
Clinical trial identification
NCT00835978 and NCT00920816
Legal entity responsible for the study
B.I. Rini, E. Jonasch: has received research funding and consulting fees from Pfizer. V. Grünwald: has received consulting fees and honoraria from Pfizer, Roche, GSK and Novartis, research funding from Wyeth Oncology, and a lecture honorarium from Bayer. M.N. Fishman: reports research funding and honoraria from Aveo, Altor Biosciences, Bayer, Genentech, GSK, and Pfizer; research funding from BMS, Eisai and Exelixis; honoraria from Alkermes and Prometheus. Y. Tomita: served as a consultant for Novartis and Ono, and received speaker honoraria and grants from Pfizer, Bayer and Novartis, grants from AstraZeneca and Astellas, and speaker honoraria from GlaxoSmithKline. M.D. Michaelson: received research funding and consulting fees from Pfizer, Novartis, and Exelixis. J. Tarazi, L. Cisar, A.H. Blair, B. Rosbrook: is a full-time employee of and declares stocks from Pfizer. T. Hutson: has received consulting fees and research funding from Pfizer, Exelexis, Eisai, Novartis, and BMS.