IO Biotech(US:IOBT) Globenewswire·2025-08-11 12:00Core Insights - IO Biotech announced topline results from the pivotal Phase 3 trial of its investigational cancer vaccine Cylembio, showing clinical improvement in progression-free survival (PFS) when combined with Merck's KEYTRUDA compared to KEYTRUDA alone [1][2][5] Study Results - The trial involved 407 patients with unresectable or metastatic melanoma, with 203 receiving Cylembio plus KEYTRUDA and 204 receiving KEYTRUDA alone [2][8] - The primary endpoint of PFS showed a hazard ratio of 0.77, with a median PFS of 19.4 months for the combination group versus 11.0 months for the control group [2][5] - A trend towards improved overall survival (OS) was observed, with a hazard ratio of 0.79, although OS data is not yet mature [2][5] Subgroup Analysis - Improvement in PFS was noted across nearly all subgroups, particularly in patients with PD-L1 negative tumors, achieving a median PFS of 16.6 months compared to 3.0 months for the control group [3][5] - In patients without prior anti-PD-1 treatment, the combination therapy resulted in a median PFS of 24.8 months versus 11.0 months for the control group [3][5] Safety and Tolerability - The combination therapy was well tolerated, with no new safety signals reported; the most common adverse events were transient injection site reactions, reported by 56% of patients in the combination arm [4][5] Future Plans - IO Biotech plans to engage with the FDA to discuss the data and potential regulatory submission for Cylembio [2][6][12] - The company will present more detailed results at an upcoming medical meeting [6][12]