Vivus obesity drug awaiting FDA review

Silver bullet for obesity patients?

Vivus's Qnexa drug, designed to treat obesity, is pending review from the US Food and Drug Administration's (FDA) Endocrinologic and Metabolic Drugs Advisory Committee, a panel of experts that reviews and evaluates all data regarding the safety and effectiveness of marketed and investigational human drugs for use in the treatment of hormonal and metabolic disorders.

The committee also provides the FDA with medical guidance in order to direct decisions regarding the marketing of new drugs.

It is ‘make or break' time for Vivus and Qnexa, with the obesity market in the US - not to mention globally - representing what is potentially a massive money spinner for the company. Currently the condition affects approximately 300 million people globally and 60 million people in the US, where it is also responsible for approximately 112,000 deaths annually. Obesity can also lead to central nervous system (CNS) disorders such as anxiety, depression and insomnia, as well as increasing the risk of diabetes and cardiovascular diseases.

As such, the global obesity therapeutic market is currently valued at approximately $5 billion.

Anti-obesity drugs

Qnexa will have competition however; currently there are two major drugs on the market for the treatment of obesity, sibutramine and orlistat.

Sibutramine is marketed as the prescription drug Meridia (approved in 1997) by Abbott Laboratories. Orlistat is marketed as a prescription drug under the name of Xenical (approved in 1999) by Roche Holding Ltd and Glaxosmithkline Plc. Despite the attractive opportunity in the obesity market, the commercial performance of these drugs has been somewhat lacklustre due to the side effects associated with them, such as hypertension and tachycardia.

As such, the 2009 sales of Meridia and Xenical were $40 million and $35 million respectively.

Qnexa, however, is a combination product of two drugs, phentermine and topiramate. Phentermine is a generic drug, which is used as a short-term treatment for the reduction of weight while topiramate is a drug approved for the treatment of epilepsy and for the prevention of migraine. The phentermine will act to decrease the appetite of obese subjects by enhancing the levels of dopamine in their brain, a chemical that suppresses appetite; meanwhile the topiramate will increase the feeling of satiety in obese patients, which is regulated by gamma-aminobutyric acid (GABA) in the brain.

Being a combination of phentermine and topiramate, Qnexa suppresses the appetite and induces a feeling of satiety, thereby reducing the craving for food, which ultimately results in the reduction of body weight. If successful in its FDA review, Vivus has the potential to dominate the anti-obesity drug market.

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