FDA wants more clinical trial data before approving Forest, Gedeon Richter psychiatric drug

NEW YORK — The Food and Drug Administration has declined to approve an experimental drug for schizophrenia and bipolar disorder developed by Forest Labs and Gedeon Richter, a Hungarian drug company, the two said Thursday.

The companies said the FDA issued a complete-response letter for cariprazine. The agency issues a complete-response letter when it has finished reviewing an application but issues remain that preclude final approval. In the letter, the FDA acknowledged the drug's efficacy, but wanted more clinical trial data.

"Given the complex pharmacokinetics and metabolism of cariprazine, we believe this request was made to better define the optimal dosing regimen to maintain the demonstrated efficacy, while minimizing the potential for the development of adverse events generally associated with this class of drug," Forest Research Institute president Marco Taglietti said.