WASHINGTON — The Food and Drug Administration on Monday approved a biotech drug to become the first medicine to treat breast cancer before surgery.
Perjeta, made by Roche’s Genentech unit, would be an option for women with a form of early-stage breast cancer who face a high risk of having their cancer spread. Surgery to remove tumors is usually the first step in treating most forms of cancer.
Doctors hope that using cancer drugs earlier could help shrink tumors, making them easier to remove. In some cases, that could preclude the need for a full mastectomy. Doctors also say that treating the disease at its earliest stages could prevent tumors from returning, though studies have not yet established that benefit.
Cancer specialists already use several chemotherapy drugs as initial treatments for cancer, but they are not formally approved for the use. The FDA originally approved Perjeta to treat breast cancer that has spread to other parts of the body after surgery.
The FDA granted the drug accelerated approval for its new use based on a study showing women who received the drug as an initial treatment were more likely to be cancer-free 12 weeks later than women who received older drug combinations. Accelerated approval is reserved for drugs that show groundbreaking results for treating life-threatening diseases in early studies.
As a condition of approval, Genentech must conduct a larger follow-up study showing the drug’s long-term benefits. Generally that means showing that patients lived longer or had a higher quality of life after taking the drug. Genentech, based in South San Francisco, Calif., has enrolled about 4,800 patients in the follow-up study, with results expected in 2016.
Dr. Paula Klein, a cancer specialist, said she will start prescribing the drug for early-stage patients immediately but stressed the need for follow-up data. ‘‘This does not yet prove to us that using the antibody in this setting will result in more cures.’’ said Klein, who directs the breast cancer program at Continuum Cancer Centers of New York.
The FDA said Monday’s approval was based on a 417-women study comparing Perjeta in different combinations against older breast cancer treatments. When Perjeta was combined with Herceptin, another Genentech drug, and standard chemotherapy, 39 percent of women saw their cancer reach undetectable levels. Only 21 percent of women experienced the same results from taking Herceptin and chemotherapy alone.
After the drug treatment, all the women also received standard surgery to remove cancerous tumors.
Like Herceptin, Perjeta only works in a subset of about 20 percent of breast cancer patients who have tumors that overproduce a protein known as HER-2.
This protein causes cancer cells to divide and grow faster than usual.