Adjuvant Everolimus in Patients with Completely Resected, Very High-risk Renal Cell Carcinoma of Clear Cell Histology: Results from the Phase 3 Placebo-controlled SWOG S0931 (EVEREST) Trial

Background and objective

EVEREST is a phase 3 trial in patients with renal cell cancer (RCC) at intermediate-high or very high risk of recurrence after nephrectomy who were randomized to receive adjuvant everolimus or placebo. Longer recurrence-free survival (RFS) was observed with everolimus (hazard ratio [HR] 0.85, 95% confidence interval [CI] 0.72–1.00; p = 0.051), but the nominal significance level (p = 0.044) was not reached. To contextualize these results with positive phase 3 trials of adjuvant sunitinib and pembrolizumab, we conducted a secondary analysis in a similar population of EVEREST patients with very high-risk disease and clear cell histology.

Methods

Postnephrectomy patients with any clear cell component and very high-risk disease, defined as pT3a (grade 3–4), pT3b–c (any grade), T4 (any grade), or node-positive status (N+), were identified. A Cox regression model stratified by performance status was used to compare RFS and overall survival (OS) between the treatment arms.

Key findings and limitations

Of 1499 patients, 717 had clear cell histology and very high-risk disease; 699 met the eligibility criteria, of whom 348 were randomized to everolimus arm, and 351 to the placebo arm. Patient characteristics were similar between the arms. Only 163/348 (47%) patients in the everolimus arm completed all treatment as planned, versus 225/351 (64%) in the placebo arm. Adjuvant everolimus resulted in a statistically significant improvement in RFS (HR 0.80; 95%CI 0.65–0.99, p = 0.041). Evidence of a survival benefit was not seen (HR 0.85; 95%CI 0.64–1.14, p = 0.3)

Conclusions and clinical implications

In patients with clear cell RCC at very high-risk for recurrence, adjuvant everolimus resulted in significantly improved RFS compared to placebo but resulted in a high discontinuation rate due to adverse events. Although the treatment HR for OS was consistent with RFS findings, it did not reach statistical significance. With a focus on risk stratification tools and/or biomarkers to minimize toxicity risk in those not likely to benefit, this information can help inform the design of future adjuvant trials in high-risk RCC