Lenvatinib (LEN) + pembrolizumab (PEMBRO) treatment in patients (pts) with metastatic clear cell renal cell carcinoma (RCC): Final results of a phase 1b/2 trial.

Abstract

e16542 Background: Immune checkpoint inhibitors (ICIs) are commonly used as first-line treatment for pts with advanced RCC. In the recent phase 3 CLEAR trial, LEN + PEMBRO showed improved objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) vs sunitinib in first-line treatment of advanced RCC (Motzer R et al. NEJM. 2021). Additional treatment options are needed for pts with disease progression on ICIs. A phase 1b trial of LEN + PEMBRO was performed in multiple tumor types and included an expansion part into a phase 2 cohort of ICI-pretreated, treatment-naïve, or previously treated ICI-naïve pts with metastatic RCC (NCT02501096). We report the final results of the RCC cohort with an extended follow-up. Methods: Eligible pts were ≥18 years old and had measurable disease. Efficacy analyses were conducted by prior therapy grouping. The primary endpoint was ORR at week 24 (ORRwk24) per immune-related (ir) RECIST by investigator assessment. Secondary endpoints included ORR, duration of response (DOR), PFS, OS, and safety. Exploratory endpoints included tumor response assessed per RECIST v1.1 by independent review committee (IRC). Subgroup analyses of the ICI-pretreated group will be included in the poster. Results: The recommended doses determined in phase 1b were LEN 20 mg daily + PEMBRO 200 mg once every 3 weeks (Taylor M et al. JCO. 2020). The study enrolled 145 pts (efficacy analysis, n=143; safety analysis, n=145). At data cutoff (August 18, 2020), the median follow-up time was 19.8 months. The ORRwk24 was 55.8% (95% CI 45.7–65.5) for ICI-pretreated pts (n=104), 72.7% (95% CI 49.8–89.3) for treatment-naïve pts (n=22), and 41.2% (95% CI 18.4–67.1) for previously treated ICI-naïve pts (n=17). The median OS for the previously treated ICI-naïve pts was 30.3 months and was not reached in the other groups. Additional efficacy analyses are shown in the table. Treatment-related adverse events occurred in 99.3% of pts; the most common were fatigue (58.6%), diarrhea (55.2%), and hypertension (40.0%). Most pts (69%) maintained the LEN starting dose or were reduced to LEN 14 mg daily (dose level −1). Conclusions: LEN + PEMBRO demonstrated promising antitumor activity with a manageable safety profile in pts with metastatic RCC, including pts who were ICI-pretreated. Clinical trial information: NCT02501096. [Table: see text]