IO Biotech Sheds 50% of Staff After FDA Blocks Cancer Vaccine Approval Path

IO Biotech is laying off approximately 50% of its workforce following a setback from the FDA, which advised the company not to submit an approval application for its cancer vaccine, Cylembio, based on current data.13

The decision comes after the Cylembio vaccine failed to show superiority to Merck's Keytruda in a recent Phase 3 melanoma trial; while IO Biotech observed a trend toward improved survival, the trial missed its main efficacy endpoint.12

Despite the FDA's feedback, IO Biotech's leadership remains confident in the potential of Cylembio and plans to engage in further discussions with both US and European regulators regarding the data and future study designs.1

The layoffs are part of a broader capital conservation plan, as IO Biotech anticipates its funds will run out in the first quarter of 2026 unless further action is taken.1

Cylembio is an 'off-the-shelf' vaccine derived from IO's T-win platform, aiming to stimulate T cells against tumor cells in the tumor microenvironment, distinct from more personalized mRNA vaccines.12

The FDA recommended against pursuing approval with data from the failed study, prompting restructuring and workforce reductions as IO Biotech pivots to new strategies for regulatory approval.3

Sources:

1. https://www.fiercebiotech.com/biotech/io-lays-50-employees-after-fda-derails-cancer-vaccine-approval-plan

2. https://www.biopharmadive.com/news/IO-biotech-melanoma-cancer-vaccine-study-results-cylembio/757294/

3. https://medwatch.com/News/Pharma_Biotech/article18587181.ece