Product Candidates

Our Approach to Obesity Treatment

At Orexigen our science and innovation is our strength. Obesity results from an energy imbalance caused by the consumption of more calories than the body is able to burn over an extended period. The cause of this imbalance is complex and is influenced by the convergence of various environmental, behavioral and genetic factors. However, at the crux of obesity is the role of the brain and CNS in regulating body weight.

The brain is the master regulator of the body, affecting every fundamental function including decisions about what people eat, when we eat, how much we eat and how much energy we burn. When an overweight person starts to lose weight, the brain causes the body to fight back by increasing hunger and slowing down metabolism, making it more difficult to burn calories and thereby counteracting weight loss. Over time, the brain of an obese person becomes insensitive to the “stop” signals from the body, resulting in continued consumption of food beyond the body’s energy needs. Thus, many interventions for weight loss may be successful in the short term, but results are typically difficult to maintain.

Two basic opposing neuronal populations work through the melanocortin 4 receptor (MC-4) in concert to maintain the body’s weight at a constant level. Activation of the proopiomelanocortin or POMC neurons reduces appetite and increases energy output. Activation of the neuropeptide Y/Agouti-Related Peptide (NPY/AgRP) neurons increases hunger and conserves energy when energy reserves, stored as fat, are low.

Orexigen’s product candidates, NB-32 and Empatic™ reflect the Company’s understanding of how the brain appears to regulate appetite and metabolism, as well as the mechanisms that come into play to limit weight loss over time.