China-based Antengene Corporation Ltd (HKG: 6996) has unveiled a transfer agreement with US-headquartered Calithera Biosciences Inc. (OTCMKTS: CALA), expanding on an earlier license agreement. Under the new agreement, Antengene will acquire all remaining rights to CB-708 (ATG-037), Calithera’s small-molecule CD73 inhibitor. This move underscores Antengene’s commitment to advancing innovative cancer therapies.
Previous Licensing Agreement
The two firms first signed a licensing deal focused on CB-708 in 2021, with Antengene agreeing to pay Calithera an undisclosed upfront fee, as well as development, regulatory, and marketing milestone payments, alongside tiered royalties on sales. According to the transfer agreement, Antengene will now acquire all patents and patent filing ownership rights relating to the drug, with all previous milestone payment and royalty commitments cancelled.
Mechanism and Development
CD73 is an immune checkpoint associated with adenosine metabolism that promotes tumor progression by suppressing the antitumor immune response and enhancing the proliferation of cancer cells through downregulation of IFN-γ, NK cells, and CD8+ T cells. Tumors utilize multiple CD73-mediated pathways to avoid immune responses. CB-708 is a highly potent, selective, orally bioavailable inhibitor of CD73, with potential as either a monotherapy or part of combination regimens against a range of tumor types. Preclinical data demonstrated that CB-708 has immune-mediated, single-agent activity in syngeneic mouse tumor models. In preclinical studies, CB-708 was well-tolerated and showed enhanced anti-tumor activity when combined with either an anti-PD-L1 immunotherapy or chemotherapeutic agents such as oxaliplatin or doxorubicin.
Future Outlook
Antengene plans to initiate Good Manufacturing Practice (GMP)-aligned manufacturing of CB-708 in the future, as well as clinical studies in solid tumors and hematological malignancies. The acquisition of full rights to CB-708 positions Antengene to further advance the development of this promising therapy. With its demonstrated potential in preclinical studies, CB-708 is poised to make a significant impact on patient outcomes in oncology. Antengene’s ongoing efforts in clinical development highlight its dedication to improving treatment options for cancer patients.-Fineline Info & Tech
