Melanoma neoantigen vaccines: Are we getting more personal now?

KEYNOTE-9421 is a randomized phase II adjuvant study in patients with resected stage III melanoma investigating a personalized neoantigen mRNA vaccine in combination with anti-PD-1. The study gave a clear signal of superiority for the vaccine plus anti-PD-1 in relapse-free and distant-metastasis-free survival but is not yet conclusive, and important questions remain.