An HIV drug has been recalled because “human error” led to a higher than normal level of a chemical which can cause cancer, its makers said.
William Burns, chief executive of Roche’s pharmaceutical division, said the impurity had been caused by interaction between two chemicals, one of them a cleaner, in a vessel in which the product was made.
The drug Viracept, whose generic name is nelfinavir, was recalled yesterday after tests on batches revealed higher than normal quantities of methane sulfonic acid ethyl ester.
The chemical is used in the drug normally but in smaller quantities, manufacturer Roche said.
Mr Burns said that the impurity was “low level” but they believed it was unacceptable in their product.
Around 550 patients in the UK are thought to be on the drug and are being urged to contact their doctor immediately.
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: “Roche has received several reports that some batches of Viracept 250mg tablets have a strange odour.
“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 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.”
Viracept is used in combination with other drugs to treat patients with HIV.
It is a protease inhibitor – a class of drugs that helped to revolutionise HIV treatment in the 1990s.
The drug works by lowering the amount of virus in the body (viral load) and slows the progression of the disease from HIV to Aids.
Viracept received marketing approval in the US in 1997 and in the EU in 1998.
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: “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.”
The news comes just days after a criminal investigation was launched following the discovery of fake medicine destined for prostate cancer patients.
It was revealed last Friday that a counterfeit batch of Casodex, a hormone treatment for men with advanced prostate cancer, had been recalled.
Patients were urged to contact their pharmacist as soon as possible if they were taking Casodex with the batch number 65520 printed on the medicine packages.
The MHRA has been investigating possible links between this and previous drug recalls of counterfeit Zyprexa, a schizophrenia drug, and Plavix, a blood thinner.
The body confirmed last week that one person has been arrested and bailed in connection with the Zyprexa investigation.