Use of First-Line Immune Checkpoint Inhibitors and Association With Overall Survival Among Patients With Metastatic Melanoma in the Anti–PD-1 Era

Abstract

In 2015, first-line programmed cell death 1 (PD-1) immune checkpoint inhibitors (ICI) were Food and Drug Administration (FDA)-approved and National Comprehensive Cancer Network (NCCN)-recommended for patients with stage IV melanoma. Few studies have assessed the overall survival (OS) and usage rate associated with first-line ICI following 2015. To determine the rates of ICI use for metastatic melanoma following FDA approval in 2015 and characterize OS associated with first-line ICI use in this patient population. In this retrospective, nationwide cohort study, adult patients (≥20 years of age) with newly diagnosed stage IV cutaneous melanoma from 2010 to 2019 were identified using the US National Cancer Database (NCDB). Data were released by NCDB in March 2022 and analyzed in June 2022. Patients were compared based on first-line ICI receipt vs not. The OS and use of first-line ICI in 2016 to 2019 were assessed using multivariable Cox and logistic regression, respectively. To account for immortal time bias in receiving ICI, landmark time points were used (the 50th and 75th percentile times from diagnosis to ICI initiation). Among 16 831 patients with stage IV melanoma, 11 435 (67.9%) of patients were male; 116 (0.69%) were Asian or Pacific Islander, 475 (2.82%) were Hispanic, 270 (1.60%) were non-Hispanic Black, 15 711 (93.55%) were non-Hispanic White, and 145 (0.86%) were other race and ethnicity; the median (IQR) age at diagnosis was 64 (54-73) years. First-line immunotherapy use increased from 8.9% (127 of 1429) in 2010 to 38.8% (685 of 1766) in 2015, and 62.5% (1223 of 1958) in 2019. Median OS improved from 7.7 months (95% CI, 7.1-8.6 months) in 2010 to 17.5 months (95% CI, 14.9-19.8 months) in 2018. For patients diagnosed in 2016 or later, OS improved with first-line ICI (median OS using the 78-day landmark: 43.7 months [95% CI, 38.1-49.1 months] vs 16.1 months [95% CI, 13.5-19.3 months] for targeted therapy or chemotherapy; adjusted P < .001)-even after adjusting for patient, disease, and treatment factors. Results were similar for the 48-day landmark. This included patients presenting with brain metastases (first-line ICI median OS using the 78-day landmark: 19.9 months [95% CI, 17.2-25.0 months] vs 10.7 months for targeted therapy [95% CI, 9.5-12.3 months], adjusted P = .001). First-line ICI use varied by patients' age, insurance status, zip code-level household income, and treating hospital type. Following anti-PD-1 approval in 2015, first-line ICI was associated with substantial OS improvements for patients with stage IV melanoma, including those with brain metastases. As of 2019, 38% of patients still were not receiving first-line ICI in the US, with use varying by patients' socioeconomic factors.