License and Collaboration Agreement with ImmuneOnco	12 Months Ended
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License and Collaboration Agreement with ImmuneOnco	License and Collaboration Agreement with ImmuneOnco On August 1, 2024, Axion Bio entered into the license and collaboration agreement with ImmuneOnco (the “IO Collaboration Agreement”). As part of this agreement, Axion Bio made a $10.0 million upfront payment to ImmuneOnco during the year ended December 31, 2024. This amount was fully expensed as in-process research and development (IPR&D) in the same year. During the year ended December 31, 2024, Axion Bio made a $5.0 million prepayment to ImmuneOnco for development costs, which was fully expensed in research and development as of March 31, 2025. A second $5.0 million prepayment for development costs was made to ImmuneOnco in April 2025, which was fully expensed in research and development as of September 30, 2025. A third $5.0 million prepayment to ImmuneOnco for development costs was made in August 2025. This amount was partially expensed under research and development, with a remaining prepaid balance of $0.3 million recorded as of December 31, 2025. In June 2025, Axion Bio achieved Investigational New Drug (IND) clearance in the United States for a Phase 1 trial of AXN-2510 in relapsed/refractory solid tumors. This milestone triggered a $10.0 million development payment to ImmuneOnco, which was paid in July 2025. This amount was fully expensed as IPR&D during the second quarter of 2025. The expenses recognized in connection with the IO Collaboration Agreement were $23.8 million and $10.0 million for the year ended December 31, 2025 and 2024, respectively, and were recorded as a component of research and development expense on the consolidated statements of operations and comprehensive loss. As of December 31, 2025, no additional milestones had been accrued as the underlying contingencies had not yet been resolved. Under the IO Collaboration Agreement, ImmuneOnco was eligible to receive additional potential near-term payments of up to $15.0 million, up to $2.1 billion in commercial, development and regulatory milestones (including up to $270.0 million in longer term development and regulatory milestones and up to $1.8 billion in commercial milestones) plus single-digit to low double-digit percentage royalties on global net sales of the licensed products outside of Greater China. On January 5, 2026, Axion Bio and ImmuneOnco entered into an agreement terminating the IO Collaboration Agreement. Under the termination agreement, Axion Bio agreed to transfer the rights, title, and interest related to AXN-2510 and AXN-27M to ImmuneOnco, and ImmuneOnco agreed to pay Axion Bio $1.8 million.

On August 1, 2024, Axion Bio entered into the license and collaboration agreement with ImmuneOnco (the “IO Collaboration Agreement”). As part of this agreement, Axion Bio made a $10.0 million upfront payment to ImmuneOnco during the year ended December 31, 2024. This amount was fully expensed as in-process research and development (IPR&D) in the same year.

During the year ended December 31, 2024, Axion Bio made a $5.0 million prepayment to ImmuneOnco for development costs, which was fully expensed in research and development as of March 31, 2025. A second $5.0 million prepayment for development costs was made to ImmuneOnco in April 2025, which was fully expensed in research and development as of September 30, 2025. A third $5.0 million prepayment to ImmuneOnco for development costs was made in August 2025. This amount was partially expensed under research and development, with a remaining prepaid balance of $0.3 million recorded as of December 31, 2025.

In June 2025, Axion Bio achieved Investigational New Drug (IND) clearance in the United States for a Phase 1 trial of AXN-2510 in relapsed/refractory solid tumors. This milestone triggered a $10.0 million development payment to ImmuneOnco, which was paid in July 2025. This amount was fully expensed as IPR&D during the second quarter of 2025.

The expenses recognized in connection with the IO Collaboration Agreement were $23.8 million and $10.0 million for the year ended December 31, 2025 and 2024, respectively, and were recorded as a component of research and development expense on the consolidated statements of operations and comprehensive loss. As of December 31, 2025, no additional milestones had been accrued as the underlying contingencies had not yet been resolved.

Under the IO Collaboration Agreement, ImmuneOnco was eligible to receive additional potential near-term payments of up to $15.0 million, up to $2.1 billion in commercial, development and regulatory milestones (including up to $270.0 million in longer term development and regulatory milestones and up to $1.8 billion in commercial milestones) plus single-digit to low double-digit percentage royalties on global net sales of the licensed products outside of Greater China. On January 5, 2026, Axion Bio and ImmuneOnco entered into an agreement terminating the IO Collaboration Agreement. Under the termination agreement, Axion Bio agreed to transfer the rights, title, and interest related to AXN-2510 and AXN-27M to ImmuneOnco, and ImmuneOnco agreed to pay Axion Bio $1.8 million.