Counterfeit Avastin cancer drug distributed in the U.S., makers are warning patients and doctors

WASHINGTON (AP) -- The maker of the best-selling cancer drug Avastin is warning doctors and patients about counterfeit vials of the product distributed in the U.S.

Roche's Genentech unit says the fake products do not contain the key ingredient in Avastin, which is used to treat cancers of the colon, lung, kidney and brain cancer.

Doctors who suspect they have received counterfeit drug should contact the Food and Drug Administration or Roche.

The company says the counterfeit products do not have Genentech printed on the packaging, which appears on all FDA-approved packages of the drug. Additionally, real Avastin contains a six-digit lot number with no letters.

The company believes drugs labeled with the following lot numbers are fake: B86017, B6011 and B6010.