Nature and management of melanoma recurrences following adjuvant anti-PD-1 based therapy

Approximately 50 % of resected stage II-IV melanoma patients develop recurrent disease by 5 years despite adjuvant anti-PD-1 therapy. Data to define best management of recurrences is lacking.

This was a multicentre, international, retrospective cohort study. Patients with resected stage II-IV melanoma who commenced adjuvant anti-PD-1-based therapy before January 2022 and later recurred were identified. Data on demographics, disease characteristics, recurrence patterns, management and outcomes were collected.

711 patients from 17 sites were included. Median age was 60 [range 16-92], 64 % were male, 2 % stage II, 91 % were stage III, 7 % stage IV. Median time to recurrence was 6.2 months (0-68.5) and median follow up time from recurrence was 19.8 months (range 0.2-73.1). 63 % recurred on anti-PD-1 therapy, 36 % off therapy [3 % < 6 months, 33 % > 6 months]. Initial recurrences were locoregional (LR) alone in 44 %, distant alone (DR) in 43 %, and 11 % in both sites. LR recurrences were managed with local therapy, alone (62 %) or with "second adjuvant" anti-PD-1 (14 %) or BRAF/MEK therapy (23 %); 12 m RFS2 was 25 %, 29 % and 69 % respectively (p = 0.0045). Definitive systemic therapy at first recurrence was given in 16 % LR and 86 % DR, with best outcomes for anti-CTLA4 + anti-PD-1 and trial combinations (24 m PFS 63 % and 69 %, respectively). The 24 m OS for the entire cohort was 65 %.

Most recurrences following adjuvant anti-PD-1 based therapy occur early and while still on drug. Outcomes are poor, regardless of site, timing of recurrence, and subsequent treatment.