IO Biotech's off-the-shelf therapeutic cancer vaccine Cylembio narrowly failed to demonstrate statistical significance for progression-free survival when combined with Keytruda in unresectable or metastatic melanoma. Despite missing the primary endpoint, data indicate early and sustained PFS improvements and positive trends in overall survival, particularly in patients not previously treated with immunotherapy. The company plans FDA discussions to pursue potential approval, emphasizing subgroup analyses and the vaccine’s safety profile.