The U.S. Food and Drug Administration has granted breakthrough therapy designation to MPDL3280A for the treatment of patients previously treated for metastatic urothelial bladder cancer who are PD-L1 positive. MPDL3280A is an anti-PDL1 monoclonal antibody, which targets PD-L1 expressed on tumor and tumor-infiltrating immune cells to activate T cells to restore their ability to effectively detect and attack tumor cells.
The breakthrough therapy designation, enacted as part of the FDA's 2012 Safety and Innovation Act, was created to expedite the development and review time of a potential new drug for serious or life-threatening disease where early clinical evidence suggests the drug may demonstrate substantial improvement compared with existing therapies.
This latest action for MPDL3280A is based on data from a Phase I study of 68 patients with previously treated, metastatic bladder cancer. Of the 30 patients who were identified as having PD-L1 positive tumors, 13 patients (43%) responded to the drug, having their tumors shrink after six weeks of follow up, and 2 patients (7%) had no radiographic evidence of tumor after 12 weeks of follow up. Four out of 35 patients in the study who were PD-L1-negative responded to the drug, having some tumor shrinking (11%).
Additional follow-up data were presented at the American Society of Clinical Oncology Annual Meeting (Abstract 5011).
The drug is marketed by Genentech.