The widely used cancer drug bevacizumab (Avastin) is associated with a more than fourfold increased risk of severe urinary protein loss, a new review finds.
This major loss of protein from the kidney into the urine can lead to significant kidney damage and reduce the effectiveness of the cancer drug, say the researchers, who are from Stony Brook University Cancer Centre in New York.
The findings, culled from an analysis of 16 studies involving more than 12 000 cancer patients, suggest that doctors need to monitor the kidney health of patients being treated with bevacizumab. The report was released online June 10 in advance of publication in an upcoming print issue of the Journal of the American Society of Nephrology.
In the review, 2.2% of the patients taking Avastin experienced severe proteinura, with patients who were taking the highest doses of the drug facing an even higher risk. Also, the type of cancer played a role in the risk of kidney trouble, with kidney cancer patients seeing the greatest risk (10.2%).
Avastin recently approved
Bevacizumab belongs to a class of drugs known as angiogenesis inhibitors, which reduce the formation of new blood vessels around tumours. Avastin (bevacizumab), manufactured by Genentech, was recently approved to treat the most common type of kidney cancer.
In 2009, the US Food and Drug Administration approved the use of Avastin in concert with interferon-alfa, an immunotherapy drug, to treat renal cell carcinoma that has spread to other organs in the body. A phase III trial found that the drug combination increased progression-free survival time by approximately five months, compared to use of interferon-alfa alone. The study wasn't able to determine whether the dual treatment extended patients' lives, according to the American Cancer Society.
The study did find, however, that patients taking both Avastin and interferon-alpha were more likely to suffer severe side effects, including bleeding, high blood pressure, protein in the urine, fatigue, and weakness, according to the cancer society.
Kidney cancer is the eighth most commonly diagnosed cancer in the United States. The cancer society estimates that there will be about 57 760 new cases of kidney cancer in the United States this year, and about 12,980 people will die from the disease. - (HealthDay News, June 2010)