MB311 is a fully humanized monoclonal antibody recognizing the tumor-associated antigen Lewis Y. This carbohydrate antigen is expressed on 60-90 % of all epithelial cancers, with only limited expression on normal tissues, and thus represents an attractive target for cancer immunotherapy.
MB311 has been tested in an open-label dose escalation Phase I clinical trial and has demonstrated a good safety profile, an excellent pharmacokinetic profile and long-lasting cytolytic activity against tumor cells in patient sera. MB311 mediates destruction of Lewis Y expressing tumor cells by activation of ADCC (antibody dependent cellular cytotoxicity) and CDC (complement dependent cytotoxicity), and was found to inhibit signal transduction by binding to Lewis Y glycosylated growth factor receptors expressed on tumor cells.
Another clinical phase I trial was performed aiming at the investigation of safety and tolerability as well as therapeutic efficacy of MB311 in cancer patients with malignant effusions. MB311 was well tolerated, permeated into malignant effusion and attracted immune cells leading to decreased tumor cell counts in the effusion. In the case of strong LeY ex-pression of malignant cells in the effusion a pronounced decrease in LeY, EpCAM and Her2/neu positive tumor cells and a significant reduction of the effusion volume could be demonstrated.
Regarding the further clinical development (e.g. clinical Phase II study) of its lead product MB311, Meridian Biopharmaceuticals is interested to enter into co-development with a strategic partner which is specialized in GMP manufacturing / industrial scale production.