WASHINGTON (Reuters) - An experimental weight loss drug that pairs a stimulant with an epilepsy drug helped patients lose weight and keep it off for a year and also lowered blood pressure, a researcher said on Tuesday.
A consultant to Mountain View, California-based Vivus Inc said three separate studies showed patients lost more weight when they took the highest doses of Qnexa, which is up for Food and Drug Administration approval in July.
Shares in Vivus soared 13.6 percent to $11.73 a share in early afternoon trading.
Drops in blood pressure were small but clear and equated with the weight loss, said Dr. Suzanne Oparil of the University of Alabama at Birmingham.
“The weight loss is very impressive, and it is good that there is concomitant reduction in blood pressure,” Oparil said in a telephone interview from a meeting of the American Society of Hypertension in New York.
Oparil, a past president of the American Heart Association, pooled and analyzed the results of three separate studies of Qnexa in nearly 8,000 overweight and obese patients.
“At week 58 there is a nice weight reduction,” she said. The higher the dose, the more weight loss and the more blood pressure went down, she said.
The patients who got the highest dose along with diet and exercise advice lost about 10 percent of their body weight on average, she said.
Vivus is trying to improve on the notorious “fen-phen” combination pulled off the market in 1997 after it was found to damage the heart and cause sometimes fatal cases of pulmonary hypertension.
Fen-phen combined fenfluramine and phentermine. Phentermine, a stimulant now available generically, appears safe and is used at low doses in Qnexa along with the epilepsy drug topiramate, available generically and sold by Johnson & Johnson’s Ortho-McNeil unit as Topamax.
Losing just 10 percent of body weight is enough to lower cholesterol and blood pressure, reduce the risk of diabetes and early death. About 68 percent of U.S. adults are overweight or obese.
In the three studies that Oparil analyzed, about 80 percent of the patients were women, most morbidly obese with weights of 220 to 260 pounds (100 to 118 kg).
Most did not have high blood pressure but among those who did and who took the highest Qnexa dose, the systolic or top number in the blood pressure reading went down an average of 9 points, compared to 4 points for the women who got placebos.
Oparil said the most common side effects were tingling and dry mouth, each seen in 19 percent of the patients who took the highest dosages.
Topiramate acts on the nervous system and tends to act as a sedative, said Oparil. This can reduce appetite. In addition, patients said the drug made carbonated drinks taste metallic and that may have helped patients avoid sugary soft drinks.
Doses of both drugs are far lower than those usually used -- when phentermine is used alone to treat obesity, for example, or when topiramate is used for epilepsy, she said.
The FDA’s Endocrinologic and Metabolic Drugs Advisory Committee is tentatively scheduled to review Vivus’ Qnexa on July 15, the company said.
Thomson Pharma has forecast 2013 sales of $357 million for Qnexa. Vivus reported its first quarter 2010 results on Monday with a net loss of $18.8 million, or $0.23 per share.
Editing by Todd Eastham