Fumarate hydratase-deficient renal cell carcinoma - results of the exploratory analysis in the SUNNIFORECAST trial comparing Ipilimumab plus Nivolumab vs standard of care as first line treatment.

BACKGROUND

Fumarate hydratase (FH)-deficient renal cell carcinoma (RCC) is a rare, molecularly defined subgroup of non-clear cell RCC (nccRCC) lacking an approved standard treatment. We report the exploratory analysis of this entity within the SUNNIFORECAST trial.

METHODS

SUNNIFORECAST evaluated ipilimumab/nivolumab versus standard of care (SOC) in previously untreated, advanced nccRCC. The primary endpoint was the 12-months overall survival (OS) rate. Secondary endpoints included median OS, progression free survival (PFS) and overall response rate (ORR). PD-L1 expression was assessed exploratorily.

RESULTS

Of 309 randomized patients, 30 had centrally confirmed FH-deficient RCC (ipilimumab/nivolumab, n=14; SOC, n= 16). The 12-months OS rate was 85.7% (95% confidence interval [CI] 53.9-96.2%) versus 73.3% (95% CI 43.6-89.1%), median OS was 35.7 months (95% CI 16.8 months-NE) versus 24.7 months (95% CI 10.6-37.7 months, hazard ratio [HR] 0.46 [0.17-1.20]), and ORR 42.9% versus 33.3%, favoring ipilimumab/nivolumab. Twenty-four patients were evaluable for PD-L1 expression; 21 had a combined positive score (CPS) ≥1. In this subgroup, the 12-months OS rate was 80.0% (95% CI 40.9-94.6%) versus 72.7% (95% CI 37.1-90.3%), median OS 38.3 months (95% CI 8.8 months-NE) versus 24.7 months (95% CI 8.8 months-NE, HR 0.43 [0.14-1.34]) and ORR 40.0% versus 36.4% for ipilimumab/nivolumab versus SOC, respectively.

INTERPRETATION / DISCUSSION: Exploratory analyses suggest trends toward improved 12-months OS-rate, median OS and ORR with ipilimumab/nivolumab versus SOC in FH-deficient RCC. The majority of tumors demonstrated PD-L1-expression (e.g. CPS ≥ 1), warranting further investigation in prospective studies.