Pfizer embarks on total US recall because of carcinogen concerns
A total voluntary recall of Pfizer’s smoking cessation drug in the US last week because of continued concerns around carcinogen levels appears to have thrown into doubt when the local shortage of Champix (varenicline) might end.
In early August the Therapeutic Goods Administration announced that sponsor Pfizer was withdrawing two lots of Champix (varenicline) locally due to the presence of low levels of carcinogen nitrosamine impurity, N-nitrosovarenicline which were “above Pfizer’s acceptable concentration limit”.
“Long-term exposure, over many years, can increase an individual’s risk of developing cancer,” the TGA said at the time.
This came as the company’s international operation paused worldwide distribution over the concerns pending product testing.
But late last week the US Food & Drug Admninistration (FDA) announced that Pfizer had expanded the scope of its distribution stop into a voluntary recall of “all lots” of the treatment – marketed in the US as Chantix – “due to the presence of unacceptable N-nitroso-varenicline levels”.
The FDA recommended patients taking recalled varenicline continue until provided with a replacement or prescribed a different treatment noting “the health benefits of stopping smoking outweigh the cancer risk from the nitrosamine impurity in varenicline”.
The TGA has told AJP it was aware of the US recall of all batches of the 0.5mg and 1mg tablets and would seek advice from Pfizer Australia if there were “any remaining batches in the Australian market that should also be recalled”.
It said Pfizer was “unable to confirm when this situation will be resolved” with the current medicine shortage notification indicating Champix would be unavailable until 31 December 2021.
The TGA said its own investigation into unacceptable levels of N-nitrosovarenicline in Champix is “ongoing” and that it “continues to work with international regulators and the sponsor to investigate this issue”.
Pfizer Australia told AJP that Champix was currently on backorder, because of the international distribution disruption, which it was treating “with urgency”.
However,” it said, “at this time we are unable to confirm a date when the situation will be resolved”.
“Patients are recommended to consult with their healthcare professional to choose an alternate treatment option.”
“We are actively working with the TGA to communicate the appropriate information in accordance with specific actions and timing, including recalls where appropriate,” it concluded.