A new concept paper released by the European Medicines Agency's Committee for Medicinal Products for Human Use (CHMP) seeks to establish an updated framework for anti-obesity and weight control drug products.

In its 1 October concept paper, "Concept paper on the need for revision of the guideline of medical products used in weight control," CHMP looks to a November 2007 guideline on weight control, noting that two weight control products have been pulled from the market since its publication.

Paired with the updates of several other obesity-related guidelines, including one for diabetes management products, CHMP said revisions are overdue.

In regards to efficacy, EMA said it is proposing a 5% reduction in weight as being a primary endpoint for products hoping to obtain approval. It also suggested changing the current guideline to allow for regulators to occasionally require sponsors to show a product's positive effect on reducing cardiovascular mortality and morbidity before being approved. This would especially be necessary if a product reduces weight, but has negative effects on a patient's heart or other bodily functions.

"The CHMP considers that these recommendations should be further detailed, in order to allow applicants to anticipate in which situations outcome studies might be required before marketing authorization," it said.

Other uses for anti-obesity drugs may require different risk-benefit paradigms and guidances, explained EMA. If a drug is intended for treatment of sleep apnea, orthopedic conditions or fertility, for instance, a sponsor might not need to conduct standard long-term (1-year) clinical trials.

However, certain side effects may also require special monitoring depending on a treatment's mechanism of actions. Treatments working with the brain's signaling pathways, similar to antidepressants, may increase the risk of depression and suicide, explained CHMP.

The concept paper also calls for the discussion of new potential criteria for identifying patients at high risk for obesity, as well as a reassessment of the current guideline's references to endocannabinoid neuromodulators-involved in the determination of appetite-which CHMP said may be irrelevant.

The proposed overhaul to the guideline, including primary and secondary endpoints, selection of patients, trial design and safety considerations, should be done by June 2013, EMA said.