Empatic™
Background
Empatic is a fixed dose combination of zonisamide sustained release (SR) and bupropion SR. The combination of zonisamide and bupropion, in our screening model, produced an eight-fold increase in relevant neuronal activity, suggesting that this drug combination would enhance satiety and energy expenditure. Based on the strength of these results and the unique Empatic mechanism of action, we selected this product combination to complement our Contrave clinical development program.
Zonisamide, in an immediate release formulation, was approved in the United States in 2000 for the adjunctive treatment of partial seizures, a form of epilepsy. The precise mechanism of zonisamide is unknown; however, it is believed that zonisamide has a number of pharmacologic mechanisms including sodium-channel modulation and enhancement of dopamine and serotonin neurotransmission which result in weight loss. Zonisamide, given alone, has shown modest weight loss in prior clinical trials conducted at Duke University.
Bupropion was approved for marketing in the United States in 1985 for depression and in 1997 for smoking cessation. Functionally, bupropion is thought to increase the level of dopamine activity at specific receptors in the brain, which appears to lead to a reduction in appetite and increase in energy expenditure. It is currently among the most commonly prescribed anti-depressants in the United States. Bupropion has become popular in the treatment of depression not only for its clinical efficacy, but also its attractive side effect profile, including modest weight loss.