IO Biotech shares surge 19.49% intraday after positive Phase 3 Cylembio trial results presented at Jefferies conference.

IO Biotech surged 19.49% intraday following the presentation of updated Phase 3 trial results for Cylembio at the Jefferies Global Healthcare Conference on November 18, 2025. The data showed a median progression-free survival of 19.4 months with Cylembio versus 11.0 months with pembrolizumab alone, with no significant added systemic toxicity. The $5.6 billion U.S. market opportunity and plans for regulatory alignment with the FDA further bolstered investor optimism. The second news item, citing financial instability, was deemed neutral due to lack of actionable content, leaving the trial results as the primary catalyst for the intraday rally.