Five-year survival with neoadjuvant therapy in melanoma: updated pooled analysis from the International Neoadjuvant Melanoma Consortium (INMC)

Abstract

Neoadjuvant immune checkpoint inhibitors (ICIs) are standard of care for resectable stage IIIB–D melanoma, but knowledge gaps remain regarding optimal treatment type, long-term survival, postsurgical management and clinical, histopathological or molecular subgroups. We analyzed 1,038 patients treated with neoadjuvant ICIs (n = 735), BRAF and MEK inhibitors (BRAF/MEKis; n = 119) or ICI plus any targeted therapy (ICI + TT; n = 184) from 26 international sites in both trial (755, 72.7%) and nontrial (283, 27.3%) settings. ICI regimens included anti-programmed cell death protein 1 (PD-1) alone (PD-1 alone; n = 242) and anti-PD-1 plus other immuno-oncology agent(s) (PD-1 + IO; n = 489). Outcomes included major pathological response (MPR), recurrence-free survival (RFS) and overall survival (OS). An MPR was achieved in 57.8% of patients with ICIs, 51.4% with BRAF/MEKis and 44.6% with ICI + TT. PD-1 + IO elicited higher MPR rates than PD-1 alone (61.4% versus 49.5%). The 5-year RFS rate was 61.0% with PD-1 alone, 73.9% with PD-1 + IO, 37.4% with BRAF/MEKis and 76.4% with ICI + TT; the 5-year OS rates were 83.3%, 87.5%, 69.8% and 83.9%, respectively. ICI-treated patients with MPR had 5-year OS rates of 98.8% with PD-1 alone and 97.9% with PD-1 + IO and gained no benefit from continuing ICIs into the adjuvant setting. Neoadjuvant ICIs were active in BRAF-mutant melanoma (MPR, 46.3%), acral melanoma (38.1%), in-transit metastases (66.7%) and oligometastases (41.2%), although subgroup sizes and relative effectiveness varied. Survival outcomes were excellent with neoadjuvant ICIs, particularly in patients achieving MPR, but poor with BRAF/MEKis and mixed with ICI + TT. Predictive biomarker-driven trials, effective adjuvant strategies and subgroup-specific research are needed for nonresponders.