Investigational therapies in the treatment of obesity.

Obesity is a major public health concern and environmental factors are involved in its development. The hypothalamus is a primary site for the integration of signals for the regulation of energy homeostasis. Dysregulation of these pathways can lead to weight loss or gain. Some drugs in development can have favourable effects on body weight, acting on some of these pathways and leading to responses resulting in weight loss. Strategies for the management of weight reduction include exercise, diet, behavioural therapy, drug therapy and surgery. Investigational antiobesity medications can modulate energy homeostasis by stimulating catabolic or inhibiting anabolic pathways. Investigational drugs stimulating catabolic pathways consist of leptin, agonists of melanocortin receptor-4, 5-HT and dopamine; bupropion, growth hormone fragments, cholecystokinin subtype 1 receptor agonist, peptide YY3-36, oxyntomodulin, ciliary neurotrophic factor analogue, beta3-adrenergic receptor agonists, adiponectin derivatives and glucagon-like peptide-1. On the other hand, investigational drugs inhibiting anabolic pathways consist of the ghrelin receptor, neuropeptide Y receptor and melanin-concentrating hormone-1 antagonists; somatostatin analogues, peroxisome proliferator-activated receptor-gamma and -beta/delta antagonists, gastric emptying retardation agents, pancreatic lipase inhibitors, topiramate and cannabinoid-1 receptor antagonists. These differing approaches are reviewed and commented on in this article.