IO Biotech announced it will file for bankruptcy after its cancer vaccine program failed in a key trial, according to an SEC filing. The Danish company’s decision follows an earlier FDA refusal related to its melanoma vaccine Cylembio, which narrowly failed to beat Merck’s Keytruda in Phase 3 by progression-free survival. After FDA interactions, the company cut jobs and explored a revised trial strategy, including efforts to adapt to regulator expectations. Ultimately, the company said it intends to shut down operations and seek bankruptcy protection, with a trustee expected to manage liquidation of assets. The outcome is another sign of how tight regulatory and financing conditions are becoming for late-stage biotech, especially when clinical trial results don’t clearly establish superiority versus existing standards. For the sector, IO Biotech’s closure is a reminder that even small statistical misses can translate into program-level existential risk once combined with regulatory refusal and cash runway constraints.