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. Accelerated approval usually is considered when results from one or more smaller, phase II clinical trials suggest that the new medicine may be a good option for people who haven't responded or stopped responding to other available treatments already approved by the FDA.
The FDA decided to not consider accelerated approval for T-DM1 to treat HER2-positive, advanced-stage breast cancer based on phase II clinical trial results available as of August 2010. Still, researchers will continue to study T-DM1 and the medicine may be considered for approval in the future, possibly in 2012 when phase III study results are expected to be available.
Roche is headquartered in Basel, Switzerland. Genentech, based in San Francisco, Calif., is a unit of Roche.