Melanoma Recurrence After Adjuvant Targeted Therapy: A Multicenter Analysis.

10016 Background: Adjuvant targeted therapy (TT) improves relapse free survival (RFS) in patients (pts) with BRAF mutant stage 3 melanoma. The outcomes and optimal management of pts who relapse after adjuvant TT is unknown. Methods: Pts from 21 centres with recurrent melanoma after adjuvant TT were included. Disease characteristics, adjuvant therapy, recurrence, treatment at relapse and outcomes were examined. Results: 87 pts developed recurrent melanoma; 21 (24%) during and 66 (76%) after cessation of adjuvant TT. Median time to 1st recurrence was 16.3 months with median follow up after 1st recurrence of 31 months. 30 (34%) pts recurred locoregionally, 51 (59%) pts developed distant recurrence and 6 (7%) pts had both. Of those who recurred locoregionally, 23/30 (77%) pts underwent surgery to no evidence of disease, only 3 (13%) of which received adjuvant anti-PD1 therapy, and 15/30 (50%) subsequently developed distant disease. 29 (33.3%) pts have died. 75 (86%) pts received systemic therapy at either 1st or subsequent recurrence. 40 (46%) pts received 1st line anti-PD1 based therapy (single agent anti-PD1, anti-PD1 with ipilimumab or anti-PD1 with investigational agent), 12 (14%) pts received ipilimumab monotherapy, 18 (21%) pts received retreatment with combination BRAF/MEK inhibitors and 5 (6%) pts received other agents (chemotherapy, TVEC). 57 (66%) pts had disease that was assessable for response rate (RR). RR after relapse was 69.7% (23/33) to 1st line anti-PD-1 based therapy, 46% (6/13) to TT and 9% (1/11) to ipilimumab monotherapy (Table). Median overall survival (OS) from date of 1st recurrence for all pts was not reached. OS varied by drug class received as 1st line systemic therapy after relapse. 3 year OS was 79% for anti-PD-1 based therapy, 55% for TT and 25% for ipilimumab. Conclusions: This study demonstrates that pts who relapse after adjuvant TT may respond to subsequent immunotherapy at similar rates to the treatment naïve setting. [Table: see text]