The current state and future of neoadjuvants in resectable melanoma: Review of phase II/III studies conducted between 2018-2022.

Abstract

e21568 Background: Adjuvant therapy with single agent anti-PD1 and BRAF/MEK-inhibitors (BRAF/MEKi) is approved for patients diagnosed with high-risk stage III melanoma. The goal of adjuvant therapy is to prevent the growth of the occult metastasis to distant organs. The premise of neoadjuvant therapy in clinical stage III melanoma is to allow for a better antigen exposure when checkpoint inhibitors are administered. We aimed to get an overview of the current state of neoadjuvant therapy in resectable melanoma. Methods: A systematic literature search was conducted in November 2022, using PubMed, American Society of Clinical Oncology (ASCO) Journal of Clinical Oncology and European Society for Medical Oncology (ESMO) abstract databases. Eligible studies included Phase 2 and 3 randomized controlled trials (RCT), single-arm trials, pooled analyses, and planned future trials published between 2018-2022 looking at the efficacy of neoadjuvants in resectable melanoma. Two individuals (CL and MM) screened all the studies, and 3 individuals (CM, MM, MW) went over the list of Abstracts. Primary outcomes and secondary outcomes, as well as median duration of follow up and Grade 3 or above adverse effects (AEs) were recorded. Abstracts with more recent findings or final publications were excluded in the final analysis. Results: A total of 14 published studies (4 RTCs, 5 single-arm, 2 OpACIN-neo and 3 related sub-analysis studies) and 16 abstracts (5 ESMO, 11 ASCO) were identified, representing 34 unique Neoadjuvant arms and a total of 1,496 patients. Thirteen of 27 trials making 71% of patients (n = 1061) tested immune checkpoint inhibitors (ICIs). Four of 27 trials of total n = 112 tested BRAF/MEKi. All ongoing or future studies (7 trials) tested combination of ICI with BRAF/MEKi or other molecules such as MDM2 inhibitors, interferon-α, or oncolytic viruses. Most of studies (54% of ICI studies, 50% of BRAF/MEK inhibitor trials, and 80% of other studies) used pathological response as their primary outcome. Other primary end points included event-free survival (EFS) and relapse-free survival (RFS), and 13/14 published studies and 13/16 abstracts met the primary end point. A pooled analysis of complete pathologic response (pCR) revealed an estimate of 38.3% ± 19.7 (mean ± SD) from 16 unique ICI neoadjuvant arms, 51.9% ± 5.3 for BRAF/MEKi (from 3 data points), and 21.0% ± 7.2 for other agents/combinations (from 3 data points). Rate of ≥ Grade 3 AEs was 28.7% ± 31.0 (from 11 data points) for studies testing ICI, 32.5% ± 14.1 (from 6 data points) for BRAF/MEKi, and 23.6% ± 20.2 (from 3 data points) from studies testing other agents/combinations. Conclusions: Recent studies have shown that neoadjuvant in resectable melanoma can offer increased therapeutic efficacy. While past studies have focused on PD-1 and CTLA-4 inhibitors, ongoing and future studies are beginning to test newer agents and novel molecular targets.