IO Biotech Posts Wider Loss in Q2, Misses Primary Endpoint in Phase 3 Trial for Cylembio in Advanced Melanoma

Io Biotech reported a Q2 net loss of $26.2 million and used $9.0 million in cash, with cash and cash equivalents at $28.1 million. The company's lead cancer vaccine candidate, Cylembio®, missed its primary endpoint for statistical significance in a Phase 3 trial for advanced melanoma, but showed clinical improvement in progression-free survival. The trial's outcome and funding runway are now in focus.

Io Biotech (NASDAQ:IOBT), a clinical-stage oncology company, released its second quarter results on August 14, 2025. The company reported a GAAP net loss of $26.2 million for Q2 2025, an increase from the prior year’s loss of $20.7 million. This loss was partly driven by a $2.6 million GAAP warrant revaluation loss and higher interest expenses following loan drawdowns. The company used $9.0 million in cash during the quarter, leaving it with $28.1 million in cash and cash equivalents at quarter end [1].

The most significant update was the outcome of the pivotal Phase 3 trial for Cylembio®, Io Biotech’s lead cancer vaccine candidate. The study, known as the IOB-013/KN-D18 trial for advanced melanoma, showed clinical improvement in progression free survival (PFS), but missed its primary endpoint for statistical significance (p=0.056; threshold for significance p≤0.045). The median PFS for patients on the vaccine combination was 19.4 months, compared to 11.0 months for the control arm. However, the primary endpoint’s statistical miss means regulatory approval is not guaranteed. The company plans to meet with the U.S. Food and Drug Administration (FDA) in fall 2025 to discuss the results and potential next steps for a Biologics License Application [1].

Io Biotech's financials reflect heavy investment in research and development, with expenses climbing to $16.7 million (GAAP) for the quarter. General and administrative costs (GAAP) were $6.5 million for the quarter, contributing to total operating expenses of $23.2 million (GAAP) for the quarter. The company’s balance sheet (GAAP) showed a decrease in assets and equity but an increase in liabilities as of June 30, 2025, compared to December 31, 2024, reflecting its dependence on external funding to finance ongoing trials [1].

The company’s cash runway, including a post-quarter EIB loan, is expected to last into the first quarter of 2026. However, without new sources of capital, Io Biotech will face funding needs in the near term, especially if regulatory or trial outcomes delay commercialization plans. In July 2025, after the close of the quarter, Io Biotech received an additional €12.5 million (about $13.7 million) tranche from a European Investment Bank loan, extending its operations into the first quarter of 2026 [1].

Looking ahead, the timing and outcome of discussions with the FDA will determine if and when Io Biotech can submit a formal application to market Cylembio® for advanced melanoma. The company highlighted ongoing trials in several cancer types, with more data expected in the latter half of 2025. Product and regulatory milestones in the coming quarters will be closely watched due to their influence on future funding and strategic options [1].

References:
[1] https://www.nasdaq.com/articles/io-biotech-posts-wider-loss-q2