608P - The efficacy of immune checkpoint inhibitors and targeted therapy in mucosal melanomas: A systematic review and meta-analysis

Background

Mucosal melanoma (MM) is a rare and aggressive subtype of melanoma arising from mucosal surfaces. While MMs are distinct from cutaneous melanomas (CMs) in pathogenesis, etiology and prognosis, management of both subtypes has remained largely similar, as the rarity of the disease poses a challenge to developing evidence-based clinical guidelines for MM. We performed a meta-analysis on the use of immune checkpoint inhibitors (ICIs) and targeted therapy for MM.

Methods

We searched five databases (PubMed, Cochrane, Embase, Web of Science and Google Scholar) for studies evaluating the efficacy of ICIs and targeted therapy in the treatment of locally advanced or metastatic MMs. After including only cohort and observational studies with available overall survival (OS) and progression free survival (PFS) data, the eligible studies comprised patients treated with anti-PD1, anti-CTLA4, VEGFR inhibitors or tyrosine kinase inhibitors (TKIs). For single-arm and double-arm studies that reported Kaplan-Meier curves, we digitally reconstructed individual patient data using Guyot's algorithm and calculated the OS, PFS and hazard ratios, along with the 95% confidence intervals.

Results

We included 26 studies with a total of 1911 participants. Our results show that combined anti-PD1 and anti-CTLA4 therapy had the highest 12-month OS and 12-month PFS at 0.677 (0.608,0.754) and 0.388 (0.316,0.475) respectively. This was followed by anti-PD1 therapy alone (OS: 0.602 (0.569,0.638); PFS: 0.282 (0.251,0.317)), anti-PD1 and VEGFR inhibitor combination therapy (OS: 0.506 (0.437,0.585)), TKI therapy (OS: 0.482 (0.376,0.618); PFS: 0.083 (0.037,0.187)) and anti-CTLA4 therapy alone (OS: 0.333 (0.284,0.391); PFS: 0.098 (0.059,0.165)). In the double-arm studies, anti-PD1 and anti-CTLA4 combination therapy had similar OS and PFS with anti-PD1 treatment alone (OS: HR 0.866 (0.616,1.22); PFS: HR 0.848 (0.666,1.08)), however, anti-PD1 therapy alone had significantly better PFS than anti-CTLA4 alone (HR 0.548 (0.376,0.799)).

Conclusions

Collectively, these results demonstrate that anti-PD1 and anti-CTLA4 combination therapy has the most favorable outcome in the treatment of MM, while anti-PD1 therapy is the single best agent.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.