UK drugmaker GlaxoSmithKline yesterday saw a nod of approval recommendation for its leukaemia and lymphoma drug, Arranon (nelarabine), but as expected was asked to conduct a Phase III confirmatory trial that will last six years. Shares in the UK giant had fallen slightly before the meeting as briefing papers pointed to the need for further evaluation even if marketing clearance is given.

The committee voted 11 to one that Arranon would predict clinical benefit in children and unanimously that clinical benefit would be likely in adults: complete responses were observed in 13% of paediatric patients and 18% of adults. Although no significant issues relating to clinical trial design or results of paediatric and adult Phase II studies were cited, FDA reviewers in the briefing papers had noted that a “recommendation is deferred pending the advice of Oncologic Advisory Committee,” primarily because patients taking the drug had often received other standard treatments for the diseases, thereby resulting in confusing efficacy data.

With regard to the drug’s safety, the FDA said it was satisfied with GSK’s evaluation of Arranon’s potential side effects, but warned that patients should continue to be monitored. The agent’s is associated with dose-limiting neurotoxicity and therefore, if approved, will carry a black-box warning on its label for potentially serious neurologic events. In addition, patients with decreased renal function should be also be closely monitored for toxicities due to the risk of adverse reactions in population, the FDA noted.

GSK says it is planning to conduct a Phase III trial that will investigate the drug as a front-line therapy in patients with T-cell acute lymphoblastic leukemia as part of a multi-agent, randomised, multicenter evaluation to be conducted over the next several years. Event-free survival will be the primary endpoint.