Astellas and Sutro Team Up for Immunostimulatory Antibody-Drug Conjugates (iADCs)

San Francisco-based Sutro Biopharma and Japanese Astellas Pharma are teaming up to advance developments of new immunostimulatory antibody-drug conjugates (iADCs). In the deal, Sutro will receive an upfront $90 million to develop iADCs for three biological targets, total funding may be worth up to an additional $422.5 million. Sutro has the option to share the costs and profits for developing and commercializing product candidates in the United States.

The announcement follows another setback from the FDA, which stopped Astellas’ FORTIS Phase 1/2 trial for Pompe disease gene therapy. A patient in the FORTIS study developed peripheral sensory neuropathy.

Related article: Astellas’ $20.5M Deal With GO Therapeutics to Develop Immuno-Oncology Therapeutics 

Boosting Anti-Cancer Action With iADCs

This strategic partnership will engage in the development of immunostimulatory antibody-drug conjugates (iADCs), a modality with the potential for treating cold tumors, i.e. tumors with low immune infiltrates. An iADC combines an antibody with a small molecule that induces immunogenic cell death in addition to an immune-activating molecule to boost anti-cancer activities.

“iADCs hold promise well beyond the existing success of ADCs. Sutro’s unique conjugation technology enables dual conjugations that site-specifically incorporate a potent cytotoxin that can directly kill tumor cells together with an immunostimulatory component that has the potential to locally prime an immune response to the patient’s particular tumor cells,” said William J. Newell, Sutro’s Chief Executive Officer.

Astellas hopes to tap into Sutro’s expertise in designing complex conjugated antibodies with this deal while adding new development pipelines in light of the turbulent trial landscape. Other than the Pompe disease gene therapy setback, the Japanese giant also ditched multiple projects, and redrawn plans for its AT132 x-linked myotubular myopathy (XLMTM) gene therapy, with losses exceeding $390 million in 2021 Q4 and 2022 Q1.

Both companies did not disclose the exact diseases the deal covers, and Astellas reaffirmed its dedication to its immune-oncology business despite recent challenges in its gene therapy trials.

Author

Fujie Tham