Analysis of the CLEAR study in patients (pts) with advanced renal cell carcinoma (RCC) : Depth of response and efficacy for selected subgroups in the lenvatinib (LEN) + pembrolizumab (PEMBRO) and sunitinib (SUN) treatment arms

4560 Background: In the multicenter, open-label, randomized, phase 3 CLEAR study, LEN + PEMBRO had significant PFS and OS benefits, and improved ORR vs SUN in first-line advanced RCC. Herein, we explore efficacy according to selected subgroups and the association between pts’ depth of response and OS. Methods: Pts in the CLEAR study were randomly assigned 1:1:1 to 1 of 3 treatment arms: LEN 20 mg orally QD + PEMBRO 200 mg IV Q3W; LEN 18 mg + everolimus 5 mg orally QD; or SUN 50 mg orally QD (4 weeks on/2 weeks off). We report PFS, OS, and ORR based on IMDC risk group (favorable and intermediate/poor) and presence of a target kidney lesion at baseline (post hoc analysis). Post hoc 6-month landmark analyses assessed the association between tumor shrinkage and OS. Pts who were alive at 6 months were grouped based on maximum tumor shrinkage from baseline or confirmed complete response (CR) up to 6 months. Tumor assessments were performed by independent review committee per RECIST v1.1. Odds ratios were calculated using the Cochran-Mantel-Haenszel method; HRs were based on stratified Cox proportional hazards model. Results: Among 1069 pts randomized in the CLEAR study, 355 were assigned to LEN + PEMBRO and 357 to SUN. Median follow-up was 27 months for the LEN + PEMBRO group and 26 months for the SUN group. PFS favored LEN + PEMBRO (median 22.1 months, n=243) vs SUN (median 5.9 months, n=229) in the IMDC-intermediate/poor subgroup (HR 0.36 [95% CI 0.28-0.47]); and in the IMDC-favorable subgroup (median 28.1 months, n=110 vs median 12.9 months, n=124; HR 0.41 [95% CI 0.28-0.62]). OS favored LEN + PEMBRO vs SUN in the IMDC-intermediate/poor subgroup (HR 0.58 [95% CI 0.42-0.80]); few events were observed in the IMDC-favorable subgroup thus, it was inadequate to evaluate OS. ORR favored LEN + PEMBRO vs SUN in the IMDC-intermediate/poor subgroup (72.4% vs 28.8%; odds ratio 6.60 [95% CI 4.39-9.90]) and the IMDC-favorable subgroup (68.2% vs 50.8%; odds ratio 2.00 [95% CI 1.17-3.42]). In pts with target kidney lesions, PFS, OS, and ORR were improved with LEN+PEMBRO vs SUN (table). The 6-month landmark analysis in the LEN + PEMBRO group showed that the OS rate at 24 months was 100% (95% CI not estimable [NE]-NE) for pts with confirmed CR per RECIST v1.1 and 91.7% (95% CI 53.9-98.8) both for pts with >75% to