Contamination of Johnson & Johnson's HIV drug Prezista (darunavir) has led to a recall of the product in some European countries and Canada.

J&J unit Janssen-Cilag International announced that it is currently in talks with regulatory agencies in the UK, Germany, Ireland, Austria and Canada following four consumer reports of an uncharacteristic smell of the drug, the cause of which is most likely to be trace amounts of the fungicide TBA, otherwise known as tribromoanisole.

The company said discussions with the European Medicines Agency have resulted in a so-called Class II recall at the wholesale and retail level, but that talks with regulatory authorities in Canada are still ongoing to determine the next steps.

However, the group also noted that in countries where recalls have been initiated it is estimated that less than 2,000 bottles of Prezista are affected, and so does not expect a shortage of the product because of the contamination.

Not pleasant but not toxic

While not considered toxic, TBA - a byproduct of a chemical preservative sometimes applied to wood used in product transport/storage pallets - has been linked with temporary gastrointestinal symptoms in a very small number of patients, but there have been no reported serious adverse events caused by its presence in Prezista, Janssen stressed.

J&J has been hit by a stream of product recalls over the last couple of years and this is not the first time one of its products has been contaminated with TBA contamination. But the drugmaker said it is currently investigating where the breach could be happening, and what steps can be taken to "further mitigate this exposure".