On March 3, 2025, Callio Therapeutics, a biotechnology company focused on realizing the promise of multi-payload antibody-drug conjugates (ADCs) to improve cancer therapy, announced its launch with the closing of a $187 million Series A financing. Frazier Life Sciences led the round with significant participation from Jeito Capital alongside other life sciences investors, including Novo Holdings A/S, Omega Funds, ClavystBio, Platanus, Norwest, Pureos Bioventures, SEEDS Capital, and EDBI. Wilson Sonsini advised Novo Holdings, Platanus, and Pureos Bioventures on the transaction.

Callio Therapeutics, headquartered in Seattle and Singapore, intends to use the proceeds from the Series A financing to achieve clinical proof-of-concept for its HER2-targeted dual-payload ADC and a second undisclosed ADC program. Additionally, the company has secured an exclusive worldwide license from Hummingbird Bioscience for its ADC platform and related assets.

The Wilson Sonsini team that advised Novo Holdings, Platanus, and Pureos Bioventures on the transaction includes:

Corporate
Dan Koeppen
Kassandra Castillo

Technology Transactions
Lowell Segal
Rachel Slyker

National Security
Joshua Gruenspecht
Nimit Dhir

For more information, please see Callio Therapeutics' news release. Additional coverage can be found on BioPharma Dive, Fierce Biotech, and Geekwire.