Predictors of early progressive disease and antitumor effects by metastatic site in renal cell carcinoma treated with ipilimumab plus nivolumab

Background: Despite durable benefits of ipilimumab and nivolumab in metastatic renal cell carcinoma (mRCC), early progressive disease (PD), defined as disease progression within 3 months, occurs, and its predictors remain unclear. We aimed to investigate the clinical factors associated with early PD in patients with mRCC treated with this regimen. Methods: A retrospective analysis of a multi-institutional database identified 193 patients with mRCC treated with ipilimumab plus nivolumab. Logistic regression analyses assessed associations between clinical factors and early PD. Results: During a median follow-up of 17 months, patients had median overall (OS) and progression-free survival (PFS) of 35 and 14 months, respectively. Objective response and PD rates were 49.9% and 24.9%, respectively. Patients with early PD had significantly worse OS than those with non-early PD (10 vs. 42 months; P = 0.0002). Multivariate analyses identified bone metastasis and performance status (PS) as independent indicators of early PD (P = 0.03 and 0.01, respectively). Early PD rates varied by metastatic site (lung, 19.3%; bone, 31.2%; brain, 10%; and liver, 30%). Patients with clear-cell RCC had a median OS of 48 months and PFS of 22 months. The identified variables of early PD were consistent across all patient populations evaluated. Conclusions: Bone metastasis and PS predict early PD in patients with mRCC treated with ipilimumab plus nivolumab, with antitumor effect of the regimen varying by metastatic site. Clarifying the characteristics of early PD may guide clinical decision-making in treatment selection.