UPDATE: Cadila Pharmaceuticals API plant slapped for faulty follow-up on stinking APIs

When India's Cadila Pharmaceuticals got complaints from customers about some of its APIs smelling bad, the drugmaker decided the odor stemmed from an impurity, so it tweaked the manufacturing process. The problem, according to the FDA, is that the plant never conducted an investigation to determine whether the impurity was in fact the cause, so the company never knew whether it had really resolved the cause of the stench.

On several occasions, the plant had manufacturing issues, sometimes for having more than the allowable number of impurities, that it did not adequately investigate, the FDA said in a warning letter, issued Oct. 15 to a Cadila plant in Gujarat. There were three observations and other issues laid out in the letter, which the FDA posted today.

The FDA said the plant failed to put in place adequate controls to prevent API contamination that customers discovered. The plant was also chided for not protecting testing data from being deleted by employees. In addition, the inspectors said the plant was behind on testing stability samples in 2014. The drugmaker has said it has taken or is in the process of taking steps to address all of the FDA concerns, but the FDA said those steps do not go far enough.

In a statement emailed Nov. 12, the company said, "We at Cadila Pharmaceuticals Limited are following up with the US FDA on all their queries and are in the process of complying with all their requirements and addressing whatever issues raised by them. We have always maintained the highest global level quality at all our manufacturing plants and will ensure that these best of standards are always maintained."

Some of India's largest drugmakers continue to wrestle with manufacturing issues that are undermining their finances. Last week, the FDA told Ranbaxy Laboratories that it was withdrawing approvals for it to make generics of both AstraZeneca's ($AZN) blockbuster Nexium and Roche's ($RHHBY) antiviral Valcyte. The agency has approved Endo Health Solutions ($ENDP) and Dr. Reddy's Laboratories to make copies of Valcyte. The FDA has refused to say what the plan is for Nexium, which went off patent in May. India's Wockhardt reported this month that its profit in the last quarter had dropped more than $22 million, a 97% free fall, after the FDA banned two of its plants from shipping to the U.S. because of ongoing manufacturing and data integrity issues.

- here's the FDA warning letter