Last week's discovery of fake Avastin in the United States, the world's biggest market, underscored how even expensive injectable medicines, not just pills like Viagra and Lipitor, are at risk from criminal counterfeiters.

Roche, the world's leading maker of cancer treatments, said there had been a number of other "individual cases" of counterfeit Avastin in the past few years, including a previously reported incident in Shanghai in 2010.

"Counterfeiting is a huge problem for the whole industry," said Roche spokesman Daniel Grotzky. "There are less cases of biologics and Avastin counterfeiting than for lifestyle drugs, but there is a growing trend and cases involving life-threatening diseases are increasing."

Healthcare regulators on both sides of the Atlantic are investigating how bogus Avastin entered the U.S. supply chain, after travelling from through Switzerland to Britain en route to clinics in California, Texas and Illinois.

Swiss wholesaler Hadicon told Reuters it imported the Avastin from an Egyptian business called SAWA but it is not clear if the product originated in Egypt. Many counterfeit medicines have been traced back in the past to China.

In the Syrian case from 2009 Roche said it sent out a letter warning of the problem, after an analysis revealed bacterial contamination in the non-sterile copies of Avastin.

"We sent a to-whom-it-may-concern letter but we did not receive any reports of adverse events that seemed to be in connection with this case," Grotzky said.

The discovery of counterfeit Avastin in Syria was reported earlier by the Wall Street Journal.

(Reporting by Ben Hirschler; Editing by Greg Mahlich)

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