Recently, the U.S. Food and Drug Administration turned down a request for the accelerated approval of the drug Trastuzumab-DM1. Roche-Genentech’s drug was proposed for the treatment of HER2-positive breast cancer which is an advanced-stage breast cancer that has stopped responding to other treatments.
The FDA concluded that the data supporting Trastuzumab-DM1 did not meet the Biologic License Application Standard for accelerated approval because all available treatment choices for metastatic breast cancer had not been exhausted.
T-DM1 is an experimental targeted therapy medicine that's a combination of Herceptin (chemical name: trastuzumab) and a chemotherapy medicine called maytansine. Researchers are studying T-DM1 to see if it would be a good treatment for HER2-positive breast cancer.
T-DM1 is an antibody-drug conjugate which is also known as an armed antibody. Conjugate links trastuzumab with the chemotherapy agent DM1, using a stable linker that keeps the agent in one piece until it reaches its target cancer cells, according to a Roche press release. The antibody is designed to bind and penetrate HER2-positive cancer cells and then release the active drug inside the cells to destroy them.
Cancer medicines are usually considered for FDA approval when the results of a large study (called a phase III clinical trial) are available. Roche requested accelerated approval on the basis of a single-arm phase II study showing that T-DM1 led to tumor responses in a third of patients with advanced HER2-positive breast cancer. Patients in the trial had received an average of seven prior regimens.
An ongoing phase III study will continue as planned. In a statement from the company, Roche officials said they expect a global regulatory submission for T-DM1 by the middle of 2012.
Some cancer medicines are considered for accelerated approval based on the results of one or more smaller studies.