Beyond the 5-year milestone: Long-term survivorship of melanoma patients treated off-trial with anti-PD-1

Little is known about the long-term outcomes of anti-PD-1 treated patients with melanoma beyond 5 years, especially for patients treated off clinical trials. This retrospective cohort study includes patients with unresectable stage III/IV nonuveal melanoma treated with anti-PD-1 off-trial at Memorial Sloan Kettering Cancer Center between 2014 and 2017 who survived at least 5 years following their first anti-PD-1 dose (N = 139). We characterized overall survival (OS), melanoma-specific survival (MSS) estimates, treatment-free survival rates, and subsequent treatment courses. Median follow-up among 5-plus year survivors (N = 125) was 78.4 months (range 60.0–96.3). OS at year 7 (2 years post 5-year landmark) was 90.1% (95% CI: 83.0%–94.3%). Fourteen deaths occurred, seven due to melanoma. MSS at year 7 (2 years post 5-year landmark) was 95.0% (95% CI: 33.5%–95.2%). In patients who completed anti-PD-1 based therapy and did not require subsequent treatment by 5 years (N = 80), the probability of not requiring additional treatment for an additional 2 years was 95.7% (95% CI: 91.0%–100%). Patients treated with anti-PD-1 regimens off clinical trials who survive at least 5 years from initial anti-PD-1 treatment can be reassured of their excellent long-term prognosis, particularly if they did not require additional melanoma treatment during the first 5 years.