The U.S. Food and Drug Administration said on Tuesday certain samples of sitagliptin, a compound in Merck’s diabetes drug Januvia, were contaminated with a possible carcinogen.
The agency said it would not object to the temporary distribution of sitagliptin containing the impurity above the acceptable intake limit to avoid a shortage.
Shares of Merck, which was not immediately available for comment, fell sharply before recovering to trade up 0.8 percent at $89.27.
Sales of Januvia and a related combination medicine called Janumet totaled $1.23 billion in the second quarter.
The impurity Nitroso-STG-19, also known as NTTP, belongs to the nitrosamine class of compounds, some of which are classified as probable or possible human carcinogens, based on laboratory tests, the agency said….