'Human error' cause of drug recall

William Burns, chief executive of Roche's pharmaceutical division, said there had been interaction between two chemicals in a vessel the product was made in, one of them a cleaner, and that had caused the impurity.

The drug, Viracept, which is used by more than 500 UK patients, was recalled because batches were found to contain too high a level of a chemical that can cause cancer.

Tests on batches of the drug, whose generic name is nelfinavir, revealed higher than normal quantities of methane sulfonic acid ethyl ester. The chemical is used in the drug normally but in smaller quantities, the manufacturer Roche said.

Suspicions were raised after some patients reported a strange odour coming from their supplies, which come in powder and tablet form.

A company statement said: "A detailed chemical analysis of the affected tablets showed they contain higher than normal levels of methane sulfonic acid ethyl ester. In the interest of patients' safety Roche has decided to recall all batches of Viracept tablets and powder. Patients are requested to contact their doctors to discuss alternative therapies."

The Medicines and Healthcare products Regulatory Agency (MHRA) put out an alert on the drug after the "genotoxic substance" - which can affect the genes and lead to cancer - was identified. It said in a statement: "The MHRA is alerting health professionals tonight concerning a contamination with a genotoxic substance affecting the production of all batches of the medicine Viracept.

"This medicine is an antiretroviral agent for use in first-line HIV therapy. The MHRA, in conjunction with the European Medicines Agency (EMEA) and Roche, has issued a drug alert to recall this medicine from the market, to minimise the risk to patients. Patients prescribed Viracept should contact their doctor immediately. They will have to change to another appropriate medicine for their condition."

Roger Pebody, treatment adviser for the Terrence Higgins Trust, said the drug was in one of the older classes and was not widely used in the UK now. He said anyone affected should contact their doctor immediately because missing just one dose could lower the effectiveness of the overall course of treatment.

He added: "These people have probably been on the drug for several years and it has worked well for them so they have had no reason to change it. It is essential that people who are taking it go to their doctor immediately in the next day and work out with their doctor the best way to proceed."