Warning Letter: Merck & Co.

On July 22, the US Food and Drug Administration sent a warning letter to Merck and Company (Whitehouse Station, NJ) concerning the company’s manufacture of asparaginase intermediate used in the drug Elspar to treat acute lymphocytic leukemia.

The agency cited the company for failing to submit a supplement for a change in the production process and quality controls. Specifically, Merck prepared production cell culture from a pre-existing production cell culture instead of from the master cell culture, a change that required the company to file a prior-approval supplement. The company also instituted a re-isolation procedure for selecting cells for use in production of asparaginase intermediate without characterizing the new isolate prior to use in production.

FDA cited these violations in a Form 483 following a February inspection of the company’s plant in Riverside, Pennsylvania. FDA issued the warning letter because it found the company’s responses to the Form 483 to be inadequate.

–Laura Bush