IO Biotech to redesign Cylembio trial, cuts workforce by 50%

IO Biotech has received a recommendation from the FDA not to submit a Biologics License Application (BLA) for its cancer vaccine Cylembio based on the data from the IOB-013 clinical trial. The company plans to design a new registrational study for Cylembio in first-line patients with advanced melanoma. IO Biotech is implementing a restructuring, reducing its workforce by approximately 50%.

IO Biotech, a biopharmaceutical company developing immune-modulatory cancer vaccines, has received a recommendation from the U.S. Food and Drug Administration (FDA) not to submit a Biologics License Application (BLA) for its cancer vaccine Cylembio based on the data from the IOB-013 clinical trial. The company plans to design a new registrational study for Cylembio in first-line patients with advanced melanoma. Additionally, IO Biotech is implementing a restructuring, reducing its workforce by approximately 50%.

The FDA's recommendation was based on the results of the IOB-013 trial, which showed that treatment with Cylembio plus pembrolizumab improved progression-free survival (PFS), but the results narrowly missed statistical significance. IO Biotech plans to continue the dialogue with the FDA to align on the design of a new registrational study for Cylembio. The company is also restructuring to conserve capital and reduce its ongoing expense structure, expecting to incur a non-recurring charge of between $1.0 - $1.5 million in the third quarter of 2025.

Cylembio is an investigational, immune-modulatory, off-the-shelf therapeutic cancer vaccine candidate designed to kill both tumor cells and immune-suppressive cells in the tumor microenvironment (TME) by stimulating activation and expansion of T cells against indoleamine 2,3-dioxygenase 1 (IDO1) positive and/or programmed death-ligand 1 (PD-L1) positive cells. The company is currently conducting a pivotal Phase 3 trial (IOB-013/KN-D18; NCT05155254) investigating Cylembio in combination with Merck’s anti-PD-1 therapy, KEYTRUDA® (pembrolizumab) versus pembrolizumab alone in patients with advanced melanoma.

IO Biotech maintains global commercial rights to Cylembio and is headquartered in Copenhagen, Denmark, with US headquarters in New York. The company is advancing its lead cancer vaccine candidate, Cylembio, in clinical trials, and additional pipeline candidates through preclinical development.