(AP) -- Counterfeit versions of the popular cancer drug Avastin obtained by European regulators contain a variety of chemicals, but not the active ingredient found in the genuine drug, according to drugmaker Roche.
The Swiss drugmaker says an analysis of the contents of the vials picked up traces of 10 substances, ranging from starch and salt to chemicals like acetone, a solvent used in paint thinner.
Roche said it is unclear whether the substances would cause harmful effects in patients.
The Food and Drug Administration is investigating the source of counterfeit Avastin imported and distributed by a U.S. wholesaler to doctors here. Authorities in Europe have traced the counterfeit product back through distributors in Britain, Denmark and Switzerland. The original country of origin is still unclear.
Explore further: Roche warns of counterfeit cancer drug in US