The US Food and Drug Administration has formally knocked back Johnson & Johnson’s application to market Zarnestra (tipifarnib) in the treatment of leukaemia.

The move does not come as much of a surprise, given that the agency’s advisory committee gave the application the thumbs down in May, saying that Phase III data be included in the regulatory dossier [[06/05/05b]]. J&J had been hoping to win a nod using data from a single arm, Phase II study of Zarnestra in elderly patients with poor-risk acute myeloid leukaemia. However, the committee voted against recommending such an approval, saying only a small number of patients seemed to benefit from the drug.

The company said that a not approvable letter from the FDA explained why the drug could not be approved based on currently submitted data. It said that it was reviewing the letter and would determine the appropriate next steps.