The colorectal cancer drug Avastin has been linked to two serious complications in a small number of patients worldwide, the drug's manufacturer warned Canadians on Friday.
Health Canada approved the drug for use in Canada last September, saying that when used in combination with other drugs, it extended the lives of colorectal cancer patients by about five months.
Avastin works by stopping the blood supply to cancerous tumours.
It is also being tested as an experimental drug for prostate, kidney, pancreatic and ovarian cancer.
Although it is not licensed for use in eyes and hasn't undergone extensive testing for that purpose, it is also injected into retinas leaking from the wet form of age-related macular degeneration.
There have been reports of patients experiencing complications in the brain while taking the drug, Hoffmann-La Roche Ltd., the maker of Avastin, said in advisories to health-care professionals and the public posted by Health Canada.
In all three confirmed cases worldwide of one complication, called hypertensive encephalopathy, the patients had a medical history of very high blood pressure. One case resulted in death. None of the cases was in Canada.
Hypertensive encephalopathy is a complication of severe high blood pressure that affects the brain. It may be reversed if blood pressure is reduced to near normal levels within hours.
The other complication, called reversible posterior leukoencephalopathy syndrome or RPLS, is a rare neurologic disorder that can cause seizures, headache, altered mental status and visual disturbance.
Doctors should stop using Avastin in patients who develop RPLS, which is also reversible if recognized and treated promptly, the advisory said.
There have been four confirmed and 10 suspected cases of RPLS reported worldwide, out of 67,000 patients exposed. One of the suspected cases was in Canada. Symptoms started from 16 hours to one year after starting Avastin, the company said.
Signs and symptoms of RPLS may include:
- Very high or high blood pressure.
- Headache.
- Nausea.
- Vomiting.
- Vision problems.
- Seizures or confusion.
- Vision problems or blindness.
- Dizziness.
People who develop any of the above are advised to contact their doctor or health-care professional immediately.
Related
External Links
- Avastin safey info. for public, Health Canada
- Avastin safey info. for health professionals, Health Canada
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