e21534 Background: Nivolumab is approved in the United States and other countries as an adjuvant treatment for patients with completely resected stage III–IV melanoma based on results of the phase 3 CheckMate 238 trial, though the trial enrolled a limited number of patients with stage IIIA disease (AJCC-8). The objective of this real-world study is to describe characteristics, treatment patterns, and outcomes of patients with resected stage IIIA melanoma (AJCC-8) treated with adjuvant nivolumab or monitored with observation. Methods: In this retrospective, chart-review study, physicians from Cardinal Health’s proprietary Oncology Provider Extended Network (OPEN) extracted data from electronic health records of patients who had undergone complete surgical resection of stage IIIA melanoma between Jan. 1, 2018, and Dec. 31, 2019. Recurrence-free survival (RFS) and overall survival (OS) were evaluated from the date of resection and compared between the adjuvant nivolumab and observation cohorts using log-rank tests and adjusted Cox proportional hazards models (covariates included age, sex, race, region, payer type, ECOG PS, and Charlson Comorbidity Index). Discontinuations and deaths due to adjuvant nivolumab toxicity were assessed. Results: This study included 171 patients treated with adjuvant nivolumab and 38 patients monitored with observation. In the adjuvant nivolumab and observation cohorts, respectively, mean age was 57.4 and 68.1 years; most patients were male (59% and 68%) and white (90% and 87%); and median follow-up from resection was 20.7 and 25.0 months. Sentinel lymph node tumor burden of < 1 mm was reported in 12% (n = 20) and 16% (n = 6) of patients in the adjuvant nivolumab and observation cohorts, respectively. The scheduled treatment course with adjuvant nivolumab was completed by 91% of patients (n = 155). RFS and OS rates were numerically higher with adjuvant nivolumab than with observation (Table). There was a trend toward RFS and OS benefit with adjuvant nivolumab versus observation (unadjusted RFS HR 0.53, 95% CI 0.26–1.09; adjusted RFS HR 0.62, 95% CI 0.28–1.40; unadjusted OS HR 0.55, 95% CI 0.19–1.57; adjusted OS HR 0.81, 95% CI 0.25–2.61). Discontinuation of adjuvant nivolumab due to toxicity occurred in 2% of patients (n = 4); no treatment-related deaths were reported. Conclusions: These real-world results confirm that patients with resected stage IIIA melanoma (AJCC-8) have a good prognosis. Treatment with adjuvant nivolumab may provide modest survival benefit over observation in this population, though increased sample size and additional follow-up are warranted.[Table: see text]
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