Pfizer Korea has interrupted the distribution of its anti-nicotine therapy Champix to dispel concerns over the treatment's nitrosamine impurities, a possible carcinogen substance.

Pfizer Korea said it has halted the distribution of Champix, its anti-nicotine therapy, as a precautionary measure to help ease concerns about the possible impurities in the treatment.
Pfizer Korea said it has halted the distribution of Champix, its anti-nicotine therapy, as a precautionary measure to help ease concerns about the possible impurities in the treatment.

According to the industry insiders on Wednesday, Pfizer Korea recently sent an official letter to local drug distributors stating that Champix 0.5mg and 1mg are out of stock due to global distribution disruption. The company said it was a preemptive move to help ease the domestic consumers’ worries.

The supply stop comes after the Ministry of Food and Drug Safety said that the Champix recalled by the Canadian authorities due to impurity N-nitrosovarenicline above the acceptable concentration level is not available in Korea. The ministry had investigated anti-nicotine therapies that use varenicline as its main compound since June 15.

Pfizer Korea said that it receives the supply of Champix from Germany.

Pfizer Korea explained that as a precautionary measure for the possibility that impurities may have arisen in the manufacturing process of the finished drug, it would halt supply while it is conducting testing and inspection.

"Pfizer Korea puts patient safety and pharmaceutical quality as top priorities," a company spokesperson told Korea Biomedical Review. "We want to ensure patient access to reliable treatments that have proven its safety."

The official stressed that pharmaceutical companies, including Pfizer, have been investigating the presence or possible formation of certain impurities called nitrosamines in anti-nicotine therapy that use varenicline as its main compound at the request of regulatory authorities.

"Recently, the Ministry of Food and Drug Safety instructed pharmaceutical companies to take follow-up measures such as testing for nitrosamine impurities in drugs containing varenicline as a precautionary measure," she said. "Pfizer will faithfully follow the instructions and will work closely with the drug regulators."

An investigation is also underway at the global headquarters level regarding impurity detection, she added.

However, the official noted that Pfizer Korea believes that the benefits of Champix outweigh the potential risk of exposure to nitrosamines via varenicline, as well as other common causes.

"Pfizer has been marketing Champix worldwide for over 15 years and has established a safety profile through a robust clinical program," she said. "The company has not found any evidence that the treatment has any cancer-related safety issues during clinical trials and subsequent use for smoking cessation."

Smokers are 15 to 30 times more likely to develop lung cancer than nonsmokers, she added.

Copyright © KBR Unauthorized reproduction, redistribution prohibited