Off-Label Use of First-Line Immunotherapy for Metastatic Renal Cell Carcinoma

Abstract

Introduction: Immune checkpoint inhibitors (ICI) were approved by the Food and Drug Administration (FDA) for patients with metastatic renal cell carcinoma (mRCC) in the second- line setting in 2015 and the first-line (1L) in 2018. Little is known about 1 L ICI use in the off-label (before FDA indication-specific approval) and postapproval settings.

Patients and methods: We retrospectively analyzed off-label and post-FDA-approval 1 L ICI receipt in a cohort of Medicare beneficiaries ≥66 years old diagnosed with mRCC from 2015 to 2019. Off-label and postapproval 1 L ICI were defined as before or on/after 4/16/2018 (1L ipilimumab/nivolumab approval). Associations between demographic characteristics and 1 L ICI receipt in the off-label and postapproval periods were examined using multivariable logistic regression.

Results: We identified 23,469 patients, of which 368 (2.4%) off-label and 1,663 (21%) postapproval received 1 L ICI. In the off-label period, patients with co-morbid conditions were more likely to receive 1 L ICI compared to patients with no co-morbidities (3+ conditions, OR = 2.00; 95% CL, 1.31-3.05). In the postapproval period, older patients were less likely to receive 1 L ICI (81+ vs. 66-70, OR = 0.60; 95% CL, 0.52-0.69), and patients who were frail were less likely to receive 1 L ICI (OR = 0.77; 95% CL, 0.69-0.87). There were not significant differences in 1 L ICI receipt based on race/ethnicity.

Conclusion: Older patients and patients with more comorbidities were more likely to receive 1 L ICI off-label, but these differences did not persist after FDA approval. After 1 L ipilimumab/nivolumab approval, patients receiving 1 L ICI were more likely younger, healthy, and receiving dual-ICI regimens.

Keywords: FDA approval; Ipilimumab; Kidney cancer; Nivolumab; Pre-approval.