IO Biotech announced clinical improvement in progression-free survival (PFS) in its pivotal Phase 3 trial evaluating the combination of its cancer vaccine Cylembio® with Merck's KEYTRUDA® (pembrolizumab) for first-line treatment of advanced melanoma. The trial showed a hazard ratio of 0.77 (95% CI 0.58-1.00) with a median PFS of 19.4 months compared to 11.0 months for the control group. However, the primary endpoint narrowly missed the statistical significance threshold, with a p-value of 0.056 against the pre-specified cutoff of 0.045. Despite this, the magnitude of the PFS benefit, positive results in PD-L1-negative patients, and favorable safety profile suggest a real drug effect. IO Biotech is pursuing FDA approval and plans to discuss the path forward later this year, potentially focusing on overall survival data or a biomarker-driven indication. The company’s stock experienced volatile trading, rising as much as 60% intraday before settling with gains around 20-24%. Separately, early-phase trials of other cancer vaccines, including Elicio Therapeutics' off-the-shelf vaccine for pancreatic cancer and the ImmunoBody DNA vaccines SCIB1/iSCIB1+ combined with checkpoint inhibitors for advanced melanoma, have shown promising immune responses and clinical benefits in difficult-to-treat cancers such as pancreatic and colorectal cancer.