Health Canada has warned against Avastin (Bevacizumab) in combination with another drug, Sutent (sunitinib malate), to treat kidney cancer. In an advisory, it has said that Avastin manufacturers, Hoffmann-LaRoche, have informed the agency of safety concerns over a rare type of anemia associated with drug interaction.
Avastin is used together with other drugs to treat cancer of the bowel and rectum which has spread to other parts of the body; however it is not approved for use for treatment of kidney cancer or for use together with sunitinib malate
In a study in the US, Avastin (at a dose of 10mg/kg given every 2 weeks) and sunitnib malate (at a dose of 50 mg once a day) was given together to treat kidney cancer that had spread. About one third of those patients were diagnosed with a rare type of anemia, Microangiopathic haemolytic anemia (MAHA).
It occurs when pieces of blood clots get caught in small blood vessels causing partial blockages. Red blood cells (the cells that carry oxygen) traveling through these blood vessels may become damaged.
In the US study some of these patients experienced side effects that are known and expected for both Avastin and sunitinib malate, such as high blood pressure.
Within 3 weeks of stopping both drugs, the patients recovered from the MAHA and the other side effects.
Some examples of signs and symptoms of MAHA are:
Dark colored urine
Dizziness, weakness or intolerance to physical activity
Enlarged spleen and liver
If you develop any of the above or any other unusual signs or symptoms, please contact your doctor or healthcare professional immediately, the Health Canada advisory said.