Astellas Pharma could secure the exclusive global rights to Audax Biosciences’ DAX-044, an antibody-cytokine fusion therapy that activates the immune system in the vicinity of the tumor.
Astellas Pharma is inking a deal worth up to $1.34 billion biobucks for the exclusive option to license an investigational immuno-oncology candidate from Audax Biosciences, which the Japanese drugmaker hopes to advance for solid tumors.
Astellas could pay Audax an undisclosed upfront payment plus potential option exercise fee totaling $285 million if the drugmaker chooses to develop the antibody-cytokine fusion DAX-044. Audax’s asset is designed to work by concentrating the immune-activating action of the IL-12 cytokine in the vicinity of the tumor, limiting systemic toxicities associated with IL-12 therapies, according to a Tuesday news release.
Under the terms of the deal, Melbourne-based Audax could additionally stand to receive up to $1.05 billion in development and commercial milestones, and is eligible for tiered double-digit royalties on worldwide net sales of DAX-044. All told, the deal could reach $1.34 billion in value.
Audax last year started research that could enable a regulatory filing seeking permission to push DAX-044 into clinical development. The biotech will be responsible for funding the asset into Phase 1 development, which is expected to start in 2027. Astellas could then assume global development, manufacturing and commercialization of DAX-044, though Audax will have the option to co-fund and co-promote the asset in Australia and New Zealand.
“DAX-044 is a promising investigational immuno-oncology program with a differentiated mechanism designed to selectively activate anti-tumor immune responses,” Takahiko Iwaya, chief strategy officer at Astellas, said in a prepared statement. “[W]e hope to advance a potential new treatment option for patients with solid tumors, including cancers where effective immune stimulation remains an important therapeutic challenge.”
The Audax agreement bolstersAstellas’ immuno-oncology pipeline,the Japanese company said. Its lead asset in the space is the bispecific immune cell engager ASP2138, currently in Phase 3 testing for stomach and gastroesophageal junction cancers. Astellas dosed the first patient of the trial in August, with initial data expected in early 2031.
Astellas is also testing ASP2138 in a Phase 1 study of pancreatic cancer, according to Astellas’ website. The company gained access to ASP2138 through a 2019 research and licensing agreement with Xencor.
Outside of Audax, Astellas has inked other recent deals to build out its immuno-oncology pipeline. In February, the pharma penned a pact potentially worth up to $1.7 billion to help develop Vir Biotechnology’s T cell engager for prostate cancer. In May 2025, Astellas linked up with China’s Evopoint Biosciences in a deal that could top $1.5 billion to advance an antibody-drug conjugate for solid tumors.
