Avastin nod shows evolving FDA thinking

By Kim Dixon

WASHINGTON (Reuters) - The U.S. Food and Drug Administration's unexpected approval of Genentech Inc's drug, Avastin, to fight breast cancer may represent an incremental evolution in the way the FDA reviews cancer drugs, a top agency official said on Friday.

Many doubted there would be a speedy clearance because the key study of Avastin's safety and effectiveness did not prove it prolonged lives. Rather, it showed the drug extended the time a patient's disease did not progress -- known as progression-free survival

It is the first time the FDA cleared use of a drug using that yardstick as a first choice treatment for doctors, the FDA's cancer chief said.

"If we only take a look at survival we may be losing some effective drugs," Richard Pazdur, FDA's oncology office chief told Reuters. "It really is the first time we have done it in a first-line setting."

Avastin is already approved in the United States to treat colon and lung cancers and is used by some doctors for breast cancer.

Casting doubt on approval was a 5-4 vote by an FDA expert panel in December to recommend the drug not be approved.

Pazdur noted European regulators have been using the standard for years. He also stressed the FDA is not abandoning survival as a study goal for key studies.

"We still believe overall survival is the gold standard for drug approvals. However, we have to be cognizant of the fact there are many reasons why survival may not be observed in clinical trials," he said.

The agency approved extended use of the drug under an accelerated program that gives the FDA more authority to mandate drugmakers to conduct post-approval studies.

"Use of this provision gives us some flexibility," he said, adding the agency is requiring Genentech keep studying Avastin to determine the link between survival and progression-free survival.

In Genentech's key study, median progression-free survival was 5-1/2 months longer in patients who got Avastin. FDA reviewers had asked the panel to weigh that against serious side effects.

Among 722 total patients, those in the Avastin group had a 20 percent increase in serious side effects, including hypertension, blood clots and heart attacks, FDA staff said.

Death attributed to the drug by the FDA was about 1.7 percent of the Avastin group versus zero in the control group.

"We realize (those risks) and have described that" in the label, Pazdur said.

The "totality of information regarding this drug," supports its use in breast cancer patients and patients and doctors need to make the individual treatment decision, Pazdur said.

(Reporting by Kim Dixon; Editing by Andre Grenon)