The Ministry of Food and Drug Safety has launched an investigation into anti-nicotine therapies that use varenicline as its main compound due to concern over the treatments containing nitrosamine impurities, a possible carcinogen substance.
According to industry sources on Monday, the ministry recently instructed pharmaceutical companies to take follow-up measures of nitrosamine impurities in drugs containing varenicline.
"Recently, we found out that there is a possibility of nitrosamine impurities in varenicline drugs," the ministry said. "As a precautionary measure, we have instructed makers to review manufacturing process of finished products, and, if necessary, take follow-up measures, such as testing for nitrosamine impurities without delay."
Varenicline is the main ingredient in Pfizer's anti-nicotine therapy Champix. Thirty-four Korean drugmakers have also launched their generic versions.
The probe comes after the regulator ordered pharmaceutical companies to inspect nitrosamine-based impurities, such as N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), and submit a report on the possibility of occurrence of nitrosamine-based impurities in all raw materials and finished drugs in November of 2019.
Local pharmaceutical companies have recently completed the data collection and submitted them to the authorities.
The ministry has also stressed that only pharmaceuticals that have submitted the data on the investigation of impurities can supply their products to the market without the nitrosamine impurities test.
Nitrosamine impurities are possible carcinogen compounds in valsartan, losartan, nizatidine, ranitidine, and metformin in Korea since 2018.
"Pharmaceutical companies, including Pfizer, have been investigating the presence or possible formation of certain impurities called nitrosamines in pharmaceuticals at the request of regulatory authorities," a Pfizer Korea official said to Korea Biomedical Review. "Pfizer will continue to review this matter and will also work closely with the Korean regulator."
The recent investigation into Varenicline drugs is the second probe conducted by the ministry regarding drug impurities this month.
On June 6, the ministry requested pharmaceutical companies to submit the results of the evaluation and testing of Azido impurities in three drug substances -- irbesartan, losartan, and valsartan -- until next Monday.
The ministry also ordered raw material manufacturers to explain reasons if they cannot secure relevant data from material manufacturers.