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Cancer drug linked to flesh-eating disease

This file image shows a vial and package for the cancer drug Avastin. THE CANADIAN PRESS/AP/HO/Genentech

Health Canada is warning that the cancer drug Avastin has been linked in rare cases to necrotizing fasciitis, the fast-moving bacterial infection also known as flesh-eating disease.

Two Canadians taking Avastin developed necrotizing fasciitis and one of them died, the federal department said Thursday in a warning issued in conjunction with the drug’s manufacturer, Hoffmann-La Roche Ltd.

The U.S. Food and Drug Administration published a similar warning in mid-March, indicating that cases of the tissue-destroying infection have mainly been seen in people with wound-healing complications or certain internal bleeding conditions.

A safety review of the drug by Roche identified 52 cases of necrotizing fasciitis reported worldwide between November 1997 and September 2012; 17 of them were fatal, including the one Canadian.

The cases occurred in patients treated with Avastin (bevacizumab) for several types of cancer. About two-thirds occurred in patients being treated for colorectal cancer. Twenty-one of the patients had gastrointestinal perforation, fistula formation or wound-healing complications that preceded the development of necrotizing fasciitis.

All patients were receiving additional chemotherapies and some had no other risk factors, the company said.

In Canada, Avastin is primarily used to treat colorectal cancer that has metastasized, or spread, said Dr. Malcolm Moore, a medical oncologist at the Princess Margaret Cancer Centre in Toronto. It can also be used to treat metastatic lung cancer, ovarian tumours and the brain cancer glioblastoma.

Moore said the drug works by preventing the formation of new blood vessels, which tumours need to thrive and grow. In patients with advanced colorectal cancer, it can extend a person’s life by months and in some cases a couple of years.

Necrotizing fasciitis can develop through infection from a number of different bacteria. Group A Streptococcus, a bacterium often found in the throat and on the skin of healthy people, is the most common cause. The bacteria usually enter the body through a break in the skin, such as a cut, burn or insect bite.

The disease threatened the life of former Quebec premier Lucien Bouchard in 1994, forcing doctors to amputate part of one leg. It is also blamed for the sudden death in 1990 of Muppets creator Jim Henson.

Symptoms can develop rapidly, sometimes within 24 hours of a minor skin injury or surgical wound, Health Canada said. Symptoms include sudden, severe pain in the affected area, fever, redness, heat, swelling or fluid-filled blisters in the skin, scaling, peeling, or discoloured skin over the affected area.

Anyone taking Avastin who develops these symptoms or notices other unusual signs or symptoms should contact their health-care professional immediately, Health Canada said.

People who have diabetes or cancer have a greater risk of developing necrotizing fasciitis because their immune systems are weakened by those diseases.