CDX-1307: a novel vaccine under study as treatment for muscle-invasive bladder cancer.

Cancer vaccines have demonstrated clinical benefit, however greater efficacy could be achieved by enhancing their immunogenicity. Owing to cancer vaccines depending on uptake and cross-presentation of tumor antigens by antigen-presenting cells (APCs), we hypothesized that greater immunogenicity would accompany strategies that direct antigen to APC-expressed mannose receptors, initiating a pathway increasing class I and II presentation to T cells. CDX-1307 consists of a human monoclonal antibody targeting the mannose receptor, fused to the human chorionic gonadotropin-β chain (hCG-β), a tumor antigen frequently expressed by epithelial cancers including bladder cancer. In Phase I studies of cancer patients, CDX-1307 was well tolerated and induced significant hCG-β-specific cellular and humoral immune responses when co-administered with GM-CSF and the Toll-like receptor agonists resiquimod and poly-ICLC. An ongoing Phase II trial evaluates CDX-1307 in patients with newly diagnosed, resectable, hCG-β-expressing bladder cancer, where low tumor burden and early intervention may provide greater potential for benefit.