GlaxoSmithKline’s new leukaemia drug Arzerra is facing a setback in the UK after the National Institute for Health and Clinical Excellence said it would not approve the drug’s use on the National Health Service.

Arzerra (ofatumumab) was granted conditional approval by European regulators in May this year for the treatment of patients with refractory chronic lymphocytic leukaemia, but only in the 25% or so who have failed to respond to standard therapy with Genzyme’s Campath (alemtuzumab) or the chemotherapy fludarabine.

Conditional marketing can be assigned to drugs that are considered to have a positive benefit/risk profile and address an unmet medical need, when the benefits of their immediate availability outweigh the risks of not having the full set of data needed for full approval.

Under these conditions GSK is required to submit further data for Arzerra to the EMA as it becomes available, but while the evidence was sufficient for a conditional regulatory approval NICE says it has not been able to recommend the drug for use on the NHS at this time because there is not yet enough evidence to show how effective the drug is compared to existing treatments.

In draft guidelines the Institute said its independent appraisal committee felt data handed over by GSK was not robust enough to show to what degree the Arzerra improves survival rates for patients with refractory CLL and how this compares with standard care, and that this uncertainty, coupled with the drug’s cost - estimated to be £81,000 per QALY - meant that it could not be considered a cost effective use of NHS resources at this time.

Defending the decision, NICE chief executive Sir Andrew Dillon said: “We can only recommend drugs where the evidence shows them to work better than current NHS treatments, and when they represent good value for money for the NHS”.

“The lack of hard evidence on disease-free and overall survival rates has also been acknowledged by the UK’s Medicines and Healthcare products Regulatory Agency and also the Food and Drug Administration in the USA,” he said, pointing out that the drug;s conditional licence was granted “on the proviso that more research must be carried out to prove its clinical benefit”.