Axitinib plus pembrolizumab in patients with advanced renal cell carcinoma: Long-term efficacy and safety from a phase Ib study.

5080 Background: Axitinib (AXI) plus pembrolizumab (pembro) showed superior overall survival (OS), progression-free survival (PFS) and response rate compared with sunitinib in a randomized Phase 3 trial in advanced renal cell carcinoma (RCC). Here, we report long-term efficacy and safety data of the combination AXI/pembro from the Phase 1 trial, with almost 5 years of follow-up. Methods: 52 treatment-naïve patients with advanced RCC were enrolled between 23 September 2014 and 13 October 2015, and were treated with oral AXI 5 mg twice daily and intravenous pembro 2 mg/kg every 3 weeks. Planned treatment duration was 2 years for pembro and not limited for AXI. Based on International Metastatic Database Consortium (IMDC) criteria, 46.2%, 44.2% and 5.8% of patients were reported as having favourable, intermediate and poor risk. Results: At data cut-off date (July 3, 2019), median OS was not reached; 38 (73.1%) patients were alive. 14 (26.9%) patients had died, none were related to treatment. The probability of being alive was 96.1% (95% CI 85.2–99.0) at 1 year, 88.2% (95% CI 75.7– 94.5) at 2 years, 82.2 % (95% CI 68.5– 90.3) at 3 years, and 66.8 % (95% CI 49.1–79.5) at 4 years. Median PFS was 23.5 (95% CI 15.4–30.4) months. Median duration of response was 22.1 (95% CI 15.1–not evaluable) months. Median time on treatment with the combination AXI/pembro was 14.5 months (n=52), median time on pembro after AXI discontinuation was 9.0 months (n=10), and median time on AXI after pembro discontinuation was 7.5 months (n=11). After stopping study treatment, 22 patients received subsequent systemic therapy, including nivolumab and cabozantinib (n=6 each). Grade 3/4 AEs were reported in 38 (73.1%) patients. 20 (38.5%) patients discontinued either drug due to AEs: 17 (32.7%) patients discontinued AXI, and 13 (25.0%) patients discontinued pembro with 10 (19.2%) discontinuing both drugs. Dose reduction of AXI due to AEs was reported in 16 (30.8%) patients. The most common AEs reported were diarrhea (84.6%), fatigue (80.8%), hypertension (53.8%), cough (48.1%), and dysphonia (48.1%). Increased alanine aminotransferase and aspartate aminotransferase occurred in 44.2% and 36.5% of patients, respectively. With this longer follow-up, there were no cumulative AEs or new AEs. OS by IMDC risk group will be presented. Conclusions: In patients with advanced RCC with almost 5 years of follow-up, the combination of AXI/pembro continues to demonstrate clinical benefit with no new safety signals. Clinical trial information: NCT02133742 .