possible Side effect of Avastin Perforated Intestines

[RandyW]

Cancer drug may raise risk of intestinal perforations

BY DELTHIA RICKS

delthia.ricks@newsday.com

11:03 PM EDT, May 27, 2009

A popular cancer drug, ushered into use on a wave of promise five years ago because it chokes off a tumor's blood supply, appears to raise the risk of intestinal perforations, a team of Long Island scientists has found.

The perforations, which can occur anywhere in the intestinal tract, are most likely to occur when the drug Avastin is used in combination with chemotherapy, according to researchers at Stony Brook University Medical Center.

"We were able to quantify perforations that actually were caused by Avastin," despite the presence of other medications, said Dr. Shenhong Wu, assistant professor of medicine and lead investigator of the new analysis.

Wu's research is what is known as a meta-analysis, a type of study in which the results of smaller medical investigations are reanalyzed to reach a conclusion. "We looked at 17 randomized clinical trials involving 12,000 patients," explained Wu, who added that his conclusion confirms that Avastin is uniquely linked to intestinal perforation.

The drug, a product of biotech giant Genentech of South San Francisco, was approved in 2004 and carries a black-box warning from the Food and Drug Administration as a result of problems generally that it has caused in patients over the years. It is an antiangiogenesis inhibitor, which means that it cuts off the blood supply to tumors, starving and shrinking them, and it is used in fighting colorectal, renal, breast and lung cancer.

Although not all patients who receive the drug develop perforations, Wu said those who do run a high mortality risk. He found the death rate for those in whom the holes developed to be 21.7 percent.

The risk for perforations appeared to be highest for patients with colorectal and renal cell cancers, the study found.

"We found that a higher dose equates with a higher risk of perforation," Wu said.

Wu's research, reported in Thursday's issue of the Lancet Oncology, sounds a note of concern not just about Avastin, but for a class of drugs - so-called targeted therapies - that were greeted with hope and optimism just a few years ago. At the time Avastin was approved, cancer researchers said that in time all cancers would be treated with targeted medications, designed to zero in on cancerous cells without harming healthy tissue.

With the exception of Gleevec, the first of the targeted drugs to be approved, none has lived up to the initial promise, said Dr. Leonard Saltz, a colon cancer specialist at Memorial Sloan-Kettering Cancer Center in Manhattan, who has also studied Avastin's potential to cause gastrointestinal perforations.

"Even though this is a serious problem, it's a rare one," Saltz said Wednesday. "We have to keep both the up side and the down side of Avastin in perspective. It's not a wonder drug. It's a drug with modest activity. And it is not risk free but its risks are frankly better than many of the drugs that are routinely used in cancer care."

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