Washington, October 24 : A pre-clinical study by biopharmaceutical company Orexigen Therapeutics, Inc. has revealed that the results of a pre-clinical research into the mechanism of action of Contrave, one of its two late-stage obesity drug candidates.

The company revealed that the combination of bupropion and naltrexone, the components of Contrave, resulted in a 94 per cent reduction of food intake in obese mice, greater than either drug alone.

The study also revealed that the drugs acted in a part of the brain where food reward pathways are located.

The drug combo directly increased firing of neurons associated with reduction in food intake and satiety.

“We originally theorized that the combination of bupropion and naltrexone, the components of Contrave, would stimulate proopiomelanocortin (POMC) neuronal firing which would lead to sustained weight loss. These new findings indicate that Contrave may also modulate food cravings through its effect on reward pathways,” said Orexigen founder and Chief Scientific Officer, Dr. Michael Cowley.

“We believe this aspect of Contrave’s mechanism of action may have the potential to differentiate it from other pharmaceutical therapies available or in development for the treatment of obesity,” Dr. Cowley added.

In one study, the effects of bupropion, naltrexone and the combination of both drugs were examined in both lean and obese mice.

It was found that treatments with bupropion, naltrexone or the combination resulted in a 34 per cent, 67 per cent, and 77 per cent reduction of food intake in lean mice. By contrast, the same treatments resulted in a 27 per cent, 49 per cent, and 94 per cent reduction of food intake in obese mice.

The interaction between bupropion and naltrexone appeared more potent in obese mice than in lean mice.

In a separate study, the effects of the same three therapies were examined by administering them selectively to the ventral tegmental area (VTA), a part of the brain that determines whether an environmental stimulus is rewarding or aversive.

The drug combo in the VTA caused a statistically significant, synergistic reduction of food intake suggesting a possible connection to the behavioural aspects of obesity.

The data were presented at The Obesity Society’s Annual Scientific Meeting (NAASO) in New Orleans. (ANI)