Half a year after being spurned by the FDA and following deep layoffs, IO Biotech has decided to close its doors for good.
The Danish biotech has ceased operations and said goodbye to its employees, C-suite and board of directors after filing for bankruptcy, according to a March 31 filing with the Securities and Exchange Commission.
A trustee appointed by the Delaware bankruptcy court will take control of the company and liquidate its assets.
IO’s troubles began in earnest last September, after the FDA advised the company not to submit its cancer vaccine Cylembio for approval. The agency’s decision was sparked by a phase 3 fail where Cylembio failed to top Merck & Co.’s Keytruda at improving progression-free survival in unresectable or metastatic melanoma.
Because Cylembio’s survival mark just barely missed statistical significance over Keytruda, IO at the time was not deterred from pursuing approval. But subsequent interactions between IO and the FDA seemed unfruitful, with the company not disclosing the outcome of a meeting meant to take place in December.
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Once the door to approval seemingly closed on Cylembio, IO responded by halving its workforce and plotting a new trial of the therapeutic vaccine to meet the regulator’s requirements. Those layoffs were followed by consideration of even further cuts in January, around the same time the oncology outfit hired a financial advisor to help explore strategic alternatives.
At the end of September 2025, IO had about $31 million in the bank. Before any layoffs, that cash was expected to last only until the first quarter of 2026.
IO’s shuttering comes on the same day as that of Lipella Pharmaceuticals, a Pittsburgh-based biotech that was developing an anti-inflammatory mouthwash to treat symptomatic oral lichen planus, an autoimmune condition affecting mucus membranes in the mouth.
Molecular glue biotech f5 Therapeutics also shut down earlier this month, with the company’s CEO citing how “brutal” the past few years have been for early-stage biotechs. The first company to be buried in the biotech graveyard this year was Nido Biosciences, which decided to wind down after its small molecule for a rare neurological disease disappointed in a phase 2 trial.
