FDA Clears New Genentech Breast Cancer Drug, in Combo With Herceptin

Xconomy San Francisco — 

The FDA gave Genentech the news it was hoping for late today, by giving the South San Francisco-based biotech company clearance to start selling a new drug for about one-fourth of women with breast cancer.

Genentech, a unit of Switzerland-based Roche, said today it received approval from the FDA to start marketing pertuzumab (Perjeta) as a new treatment for women with breast cancer that overexpresses a protein called HER2. The new targeted antibody is cleared for sale among patients who haven’t received prior treatment for the disease, and in combination with the standard trastuzumab (Herceptin) and docetaxel (Taxotere) chemotherapy.

The new drug, which I described here in a feature story yesterday, is designed to help improve upon the standard trastuzumab, the pioneering antibody that aims for the HER2 protein target. Scientists bet that by creating a different Y-shaped antibody that binds to a different location on the HER2 molecule, Genentech hoped to achieve a more comprehensive blockade of members of the HER family of signaling molecules, which are thought to help tumors spread and grow. Researchers showed in a pivotal study of 808 women that when the second antibody was added to the treatment regimen, it was able to keep tumors from spreading for an additional six months, without adding significant side effects.

“Today’s approval of Perjeta is an important advance in the treatment of HER2-positive metastatic breast cancer,” said Hal Barron, Genentech’s chief medical officer, in a statement. “Perjeta attacks HER2-positive tumors differently than Herceptin. Based on the way the two medicines work together, the combination plus chemotherapy can prolong the time before this aggressive cancer worsens compared to Herceptin and chemotherapy alone. We are very pleased to see our efforts in studying the science of HER2 translate into another personalized medicine.”

About one-fourth of the 229,000 women who are diagnosed with breast cancer in the U.S. have the gene mutation that will make them candidates for the combo of Genentech’s trastuzumab and pertuzumab. And it will add significant cost to their treatment. The original trastuzumab costs $4,500 a month, the new drug will cost an extra $5,900 a month, and most women are expected to take both drugs until their disease worsens, which is estimated to be about 18 months. That means the estimated cost of a course of treatment with the two-drug combo will be about $188,000, according to Genentech spokeswoman Susan Willson.

Trastuzumab is one of the world’s best-selling drugs, generating $6.8 billion in worldwide sales in 2010, according to Reuters. The new antibody, pertuzumab, is expected to add $274 million in annual sales by 2015, according to the average estimate of analysts polled by Thomson Reuters.