Pioneering cancer drug Avastin wins FDA's OK

By Justin Gillis
The Washington Post

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Doctors said the drug was not a cure for colon cancer, the disease it was approved to treat, but they welcomed it as progress toward their long-range goal of turning cancer into a manageable illness. Avastin blocks the action of a protein that growing tumors send out that orders the body to sprout blood vessels to supply malignant cells with nutrients. Solid tumors do not grow without a blood supply.

"This is a milestone, and it may be a turning point for cancer, because of the lowered side effects" with Avastin and similar drugs under development, said Judah Folkman, the Harvard Medical School researcher who pioneered the blood-vessel theory as a Navy doctor in the early 1960s. "Can you convert cancer to a chronic, manageable disease, like Vice President (Dick) Cheney's heart disease? When I was in medical school, that was unheard-of."

FDA Commissioner Mark McClellan announced the approval, an unusual step that reflected the importance cancer doctors have attached to the drug. He hailed Avastin as the latest in a recent string of "significant new improvements in the armamentarium for fighting colon cancer."

Avastin was approved as a first-line treatment for metastatic colon cancer, where the cancer has just spread throughout the body.

The drug was developed by Genentech, the South San Francisco company whose founding in 1976 marked the birth of the biotech industry. Most analysts believe it will be the biggest drug that company has marketed and possibly the biggest in biotech history.

In the toughest test to which a cancer drug can be subjected, Avastin extended the lives of colon-cancer patients from 15 months to 20 months. That 30 percent improvement may not sound like much, but doctors said it was unprecedented for a drug as nontoxic as Avastin appears to be.

The FDA cautioned, however, that the drug occasionally causes serious side effects, including holes in the colon, impaired wound healing and internal bleeding. More common side effects are high blood pressure, fatigue, blood clots, diarrhea, appetite loss and increased risk of infection because of decreased white blood cells.

Drugs offering far smaller gains with much greater side effects routinely are approved to treat cancer.

Patients and their insurers will pay dearly for that gain: Adding Avastin to a cancer regimen could cost a typical patient an extra $40,000 a year. Company executives said yesterday that the price was fair given Avastin's advantages. They began shipping the drug immediately, and it's expected to be available to doctors in days.

The five-month gain in life expectancy from Avastin is an average; while some patients may see little benefit, doctors said others could gain years, possibly staying alive long enough to benefit from more-advanced treatments being developed. Tests are under way to evaluate the drug in a slew of other cancers. The evidence to date suggests the drug works best for patients in earlier stages of cancer.
 
Avastin is one of a broad class of new cancer drugs based on detailed genetic knowledge of cancer. These "targeted therapies" typically are more benign than older drugs, and some have proved remarkably effective.

But tumors also become resistant to them, just as with older drugs, so doctors have been eager to put their hands on enough new targeted treatments to begin combining them into elaborate regimens, the same strategy that proved effective in treating AIDS.

Dr. Louise Grochow, chief of investigational drugs at the National Cancer Institute, said that patients may receive a cocktail of drugs designed specially for them and take them for years to control their cancer. "In many ways, you're talking about turning these diseases that people think of as death sentences into chronic illnesses," she said.

Avastin is the first drug to win approval based on the theory developed by Folkman, the Harvard researcher. As a surgeon at the Bethesda (Md.) Naval Hospital in the 1960s, he noticed tumors were fed by nutrients from newly sprouted blood vessels. If vessel growth could be blocked, he reasoned, the tumors might starve.

His theory was ridiculed for years, but he persisted, as did administrators at the cancer institute who kept funding similar work. Scientists didn't perfect techniques needed to test Folkman's theory for decades, and an entire industry had to grow that could make use of the knowledge.

By one recent count, 74 drugs that block blood-vessel growth have entered human tests.

The FDA's decision marks the second new treatment approved recently for advanced colorectal cancer. Erbitux, the drug at the center of the stock-trading scandal that brought Martha Stewart to trial, works in a different way, by blocking growth of the colon tumor, not its blood supply. The FDA is allowing it to sell based on studies proving tumor shrinkage; no one knows whether the drug will help patients live longer.

Details on Avastin's side effects were provided by The Associated Press.

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