No Details Yet, But Genentech Drug Combo Wins in Big Breast Cancer Study

Xconomy San Francisco — 

There may be a new standard of care coming for a large portion of women with breast cancer who have had surgery to remove their tumors. A drug from Roche’s South San Francisco, CA, Genentech unit, known as pertuzumab (Perjeta), has helped reduce the risk of death for such women when given in combination with other therapies in a large Phase 3 trial.

The results come from the so-called APHINITY trial, a study including 4,805 women whose breast cancer overexpresses the protein HER2—an aggressive form of the disease that affects about 14 percent of women diagnosed, according to the American Cancer Society—and have already had surgery to remove their tumors. Genentech said that pertuzumab, when combined with chemotherapy and another of its antibody drugs, trastuzumab (Herceptin), did a better job of reducing patients’ risk of death and extending the time before cancer recurrence than trastuzumab and chemotherapy alone. Genentech intends to discuss the data with regulators in the U.S. and abroad.

Genentech didn’t specify the magnitude of the benefit for these patients—that crucial data will be revealed at a future medical meeting—but success of the trial is nonetheless an important development for the Swiss oncology powerhouse and for patients. An estimated 40,450 women died in the U.S. from breast cancer in 2016, according to the American Cancer Society, making it the leading cause of cancer death among women and the second leading cause of cancer deaths overall, behind only lung cancer. Depending on the type of breast cancer, newly diagnosed patients can get surgery, radiation, or other forms of treatment. In 2012, for instance, pertuzumab was approved by the FDA on a conditional basis as a “neoadjuvant”—a treatment used prior to surgery—in combination with trastuzumab and chemotherapy. (Genentech intends to use the new data to support converting the conditional approval to a full one.)

For those who get surgery, the combination of the antibody drug trastuzumab and chemotherapy is already a mainstay “adjuvant” treatment used after surgery to help stop the cancer from returning. Genentech was trying to show that adding pertuzumab to the mix could boost the efficacy of the treatment, as the two antibody drugs each attack tumors differently. It was a high hurdle, which makes it “all the more impressive” that pertuzumab appears to have cleared it, wrote Jefferies analyst Jeffery Holford in a research note. Still, a “strong clinical benefit” will be needed for the combination to become the standard of care, which makes the detailed data critical not just for oncologist, but for payers.

Holford noted, for instance, that pertuzumab is priced at a 50 percent premium over the $4,000 monthly cost of trastuzumab, meaning the cost of the combination could push past $10,000 a month. Data has shown that trastuzumab and chemotherapy alone can lead to a 90 percent disease-free survival rate after three years. For payers to reimburse for pertuzumab, it would have to hike that number to 92 to 94 percent, he wrote.

The news, meanwhile, sent shares of Los Angeles-based Puma Biotechnology (NASDAQ: PBYI), which is developing another adjuvant breast cancer drug, tumbling about 25 percent Thursday morning.

Genentech sign at Giants AT&T Park by flickr user Rajiv Patel courtesy of a Creative Commons license