Vanda Pharmaceuticals Inc. announced the receipt of a not approvable letter from the US Food and Drug Administration (FDA) in response to its New Drug Application for iloperidone, an investigational atypical antipsychotic that was reviewed for the treatment of schizophrenia.

The FDA stated that Vanda had demonstrated the effectiveness of iloperidone at 24 mg/day in the 3101 study for which the company reported results in December, 2006, and that the efficacy was similar to the active comparator, ziprasidone (Geodon, Pfizer Inc.). In addition, the FDA also stated that iloperidone was superior to placebo in patients with schizophrenia at doses of 12-16 mg/day and 20-24 mg/day in a prior study.

However, the FDA expressed concern about the efficacy of iloperidone in patients with schizophrenia relative to the active comparator, risperidone (Risperdal, Johnson & Johnson), used in prior studies. The FDA indicated that it would require an additional trial comparing iloperidone to placebo and including an active comparator such as olanzapine (Zyprexa, Eli Lilly & Company) or risperidone in patients with schizophrenia to demonstrate the compound's efficacy further. The FDA also stated that it would require Vanda to obtain additional safety data for patients at a dose range of 20 to 24 mg/day.

"We are disappointed by this response, but will meet with the FDA to discuss this decision further," said Mihael H. Polymeropoulos, M.D., Vanda's president and CEO.

Vanda has put on hold all iloperidone-related activities pending further review.

Vanda Pharmaceuticals Inc. is a biopharmaceutical company with a focus on the development and commercialization of clinical-stage product candidates for central nervous system disorders.