Diet drug Acomplia (rimonabant), struggling with slow sales throughout Europe, has been dealt a new setback with a key U.K. advisory panel reporting it is inclined "not to recommend rimonabant for the treatment of obese and overweight adults."

The National Institute for Clinical Excellence (NICE), which provides guidance to Britain's National Health Service (NHS) on use of drugs, reported the negative preliminary recommendations of its Appraisal Committee, but said a final decision would not be made for another couple months.

Acomplia has been available in Britain through private prescription for the past year and a half, but sales have been hampered by the fact that the pricy drug is not generally available through the National Health Service. A number of other European countries also have restricted reimbursement for the drug.

In order to become generally available through the NHS in Britain and Wales, Acomplia would need to be approved by NICE through a review process now nearing a conclusion.

But NICE said "having considered the uncertainty around the effectiveness and safety of rimonabant beyond 2 years, its effect on long-term outcomes such as cardiovascular events and on the estimations of cost effectiveness of rimonabant when continuation rules and adverse effects are applied, the Committee was unable to conclude on the basis of the evidence submitted by the manufacturer that rimonabant is a cost-effective option for overweight and obese adults.

"The Committee concluded that further clarification should be requested from the manufacturer to address these areas of uncertainty in the clinical and cost-effectiveness analysis," NICE said.

NICE said that before issuing formal guidance to the NHS, the Appraisal Committee will meet again on February 5th to consider views of the manufacturer and other expert consultees which must be submitted prior to January 7th.

After considering the feedback, the Appraisal Committee "will prepare the final appraisal determination" and submit it to NICEE, which subject to any appeal, will use it as the basis for its guidance to NHS.