US biopharmaceutical group Cephalon said that a mid-stage trial of its experimental leukaemia drug lestaurtinib in patients with relapsed acute myelogenous forms of the cancer has failed to meet its clinical endpoint.

Lestaurtinib, an orally-active tyrosine kinase inhibitor, had shown promise as a potential therapy for AML because of its ability to induce cell death. However, although specific data have not yet been released, the company said an analysis of results found that while patients receiving lestaurtinib during the trial showed similar response rates to those given chemotherapy alone, there was no overall survival benefit.

Lesley Russell, executive vice president and chief medical officer at Cephalon said the firm is disappointed that the drug failed to demonstrate a benefit for patients with the disease. The news will certainly come as a blow to the firm which, according to media reports, had pinned its hopes on a 2010 launch for lestaurtinib in AML, but investors seemed to take it on the chin as the group’s share price remained largely unaffected.

In April 2006 US regulators granted lestaurtinib Orphan Drug Designation - assigned to therapies targeting patient populations of less than 200,000 Americans a year - for the treatment of AML, given that ‘just’ 12,000 people were diagnosed with the condition in 2005.