The US Food and Drug Administration has knocked back Johnson & Johnson’s bid to win approval for its top-selling anti-psychotic drug, Risperdal (risperidone), in the treatment of autism.

Although it did not disclose the exact contents of the FDA’s not approvable letter, J&J said in a statement that, given the need for treatments in this area, it was evaluating the letter and would determine the appropriate next steps.

Risperdal was first approved over ten years ago and is currently available for the treatment schizophrenia and the acute manic or mixed episodes associated with bipolar disorder. Last month, the FDA issued a warning to highlight the danger of death amongst elderly patients who were prescribed atypical antipsychotics, including Risperdal, in the off-label treatment of dementia [[12/04/05a]].