On June 4, 2026, Ona Therapeutics, a global biopharmaceutical company pioneering first-in-class antibody-drug conjugates (ADCs) to address treatment-resistant cancers, announced the closing of an oversubscribed $86.6 million Series B financing. The round was co-led by new investors Columbus Venture Partners and Mérieux Equity Partners, with participation from additional investors COFIDES and Korys, alongside all existing investors Alta Life Sciences, Asabys Partners, Bpifrance, as part of the InnoBio investment strategy, CDTI through SICC Innvierte, FundPlus NV, and Ysios Capital. Wilson Sonsini Goodrich & Rosati advised Ona Therapeutics on IP matters related to the transaction.

The proceeds from the Series B will be used to advance the clinical development of Ona’s lead program, ONA-255, a first-in-class ADC initially focused on breast cancer, and to progress ONA-389, a second first-in-class ADC targeting colorectal cancer. ONA-255 is designed to address treatment-resistant tumor biology through a differentiated mechanism aimed at improving the therapeutic index compared to earlier approaches. ONA-389 will advance toward first-in-human studies, expanding Ona’s pipeline in indications with significant unmet need. Ona currently retains full worldwide commercial rights to all its assets.

The Wilson Sonsini team that advised Ona on IP matters included Julia Minitti, Grant Margulieux, and Tina Xiang.

For more information, please see Ona’s news release.