Arena Pharmaceuticals, Inc. (ARNA), VIVUS, Inc. (VVUS), Orexigen Therapeutics, Inc. (OREX): Have Drugmakers Found the Panacea for Obesity? (Part I)

The efficacy results of the other drug under consideration, Contrave, falls in the middle of that of Belviq and Qsymia. The drug showed significant reduction in weight along with improvement in cardiometabolic risk factors, except for a slight increase in heart rate. Colntrave will have to demonstrate that its usage will not lead to adverse cardiovascular events before the drug gets approved.

Details on the recent obesity drugs on the scene and FDA’s efficacy criteria for them

Belviq acts as a selective serotonin 2C receptor agonist. It is selective in the sense that it acts only on the serotonin receptors in the brain. This is important because a similar drug that was in use previously, called fenfluramine, targeted serotonin receptors in the heart valves as well, leading to side effects. The serotonin 2C receptor is expressed in the brain, including the hypothalamus, an area believed to be involved in the control of appetite and metabolism.

The drug is supposed to promote the feeling of being satiated in a person and hence, help him/her eat less. Arena Pharmaceuticals, Inc. (NASDAQ:ARNA)has patents that cover lorcaserin in the U.S., Europe, and other jurisdictions that in most cases can continue into 2023.

(For more on these drugs, see the second part of this article)

The second major drug, VIVUS, Inc. (NASDAQ:VVUS)’ Qnexa or Qsymia, is a drug targeted towards weight loss, type-2 diabetes and obstructive sleep apnea. Qnexa is a combination of phentermine and topiramate, which is designed to decrease appetite and increase satiety, the two main mechanisms that impact eating behavior.

Orexigen Therapeutics, Inc. (NASDAQ:OREX) Contrave is combination of bupropion and naltrexone. The effect of this drug is to reduce appetite and increase energy expenditure.

Following are the criteria that the medications are expected to achieve as per the Draft FDA guideline (February 2007): “a long-term reduction in fat mass with a goal of reduced morbidity and mortality through quantifiable improvements in biomarkers such as blood pressure, lipids, and HbA1c.”

Since it is explicitly mentioned that improvements in blood pressure, lipids, and other factors related to weight loss are expected with an efficacious product, and changes in such factors will be considered in evaluating the drugs, this will turn out to be very important in determining the market success of the medications.

Obesity prescription data and statistics

While FDA guidelines are crucial to satisfy, it is also imperative for the drug efficacy to be convincing enough to the doctors expected to prescribe them. Currently, phentermine, along with metformin or topiramate, is the most prescribed medication for obesity treatment.

Physicians have been prescribing phentermine in combination with topiramate for years and patients have received the benefits of weight loss from this combination therapy.

The article Have Drugmakers Found the Panacea for Obesity? (Part I) originally appeared on

Copyright © 1995 – 2013 The Motley Fool, LLC. All rights reserved. The Motley Fool has a disclosure policy.