Factbox: A troubled history for weight-loss drugs

(Reuters) - A proposed diet drug from Orexigen Therapeutics was rejected by U.S. regulators who requested a clinical trial to resolve concerns about heart risk, the company said on Tuesday.

The setback raised new doubts about the drug industry’s ability to develop prescription weight-loss drugs. Following is a list of approved obesity drugs, others that were discontinued, and those awaiting approval:


* Late 1800s - Thyroid extract was used as a remedy for obesity but resulted in hyperthyroidism and other serious side effects.

* 1930s - Dinitrophenol reduced weight but sped up metabolism so much that it led to nerve malfunction. It was sold legally before the FDA had the power to regulate drugs.

* 1940s - Amphetamine was used as an obesity drug, though it proved addictive.

* 1960s - Rainbow pills, a combination of amphetamine, digitalis and diuretics, were linked to several deaths.

* 1971 - Aminorex, an appetite suppressant, was linked to cases of high blood pressure and removed from the European market.

* September 1997 - Fenfluramine, part of the “fen-phen” drug combination, was withdrawn from the market. American Home Products Corp, later renamed Wyeth and now part of Pfizer Inc, sold fen-phen until it was pulled from the market because of heart valve problems.

Phentermine, the other part of the “fen-phen” combination, is still considered safe at low doses. The company’s other drug, Redux, also contained a related chemical dexfenfluramine and also was taken off the market in 1997.

* November 2008 - Sanofi-Aventis pulled the plug on diet drug Acomplia after European regulators said the medicine should be withdrawn. The drug, known generically as rimonabant, never won U.S. approval after a panel of experts rejected it amid fears it may cause suicidal thoughts.

* May 2009 - Widely used Hydroxycut-brand diet supplements were pulled from store shelves after reports of liver damage.

* October 2010 - Abbott Laboratories Inc pulls Meridia or sibutramine from the U.S. market. Approved in November 1997, Meridia carried warnings about high blood pressure and a risk of heart attack and stroke in cardiovascular patients. The drug is no longer sold in Europe.


* October 2010 - Arena Pharmaceuticals Inc announced that the FDA rejected its drug, lorcaserin, seeking an independent review of the data and possibly more studies to assess cancer risk after tumors were found in animals.

* October 2010 - The FDA rejected Qnexa, a diet pill made by Vivus Inc, and asked for more data on heart risks and other issues.

* January 2011 - Orexigen Therapeutics said the FDA rejected its diet drug candidate, Contrave, and requested a clinical trial to resolve concerns about heart risks.


* Xenical, from Roche Holding AG, is an approved prescription weight-loss drug. GlaxoSmithKline markets a lower-dose, over-the-counter version called Alli. Both can cause serious liver problems, uncontrolled bowel movements and gas.

* Generic appetite suppressants phentermine and diethylpropion are sold by prescription and meant for short-term weight loss.

Reporting by Julie Steenhuysen, Susan Heavey, Jon Lentz and Lisa Richwine; Editing by Tim Dobbyn and Matthew Lewis