MOUNTAIN VIEW, Calif., Nov. 12, 2012 /PRNewswire/ -- VIVUS, Inc. (NASDAQ: VVUS) today announced that a study published in the journal SLEEP (2012; 35(11):1529-1539) found that patients with moderate to severe obstructive sleep apnea (OSA) taking phentermine and topiramate extended-release capsules achieved significant improvements in key measures of OSA and cardiovascular risk factors along with weight loss during the 28-week trial.
OSA is a chronic and potentially serious sleep disorder in which breathing is abnormally shallow ("hypopnea") or stops altogether ("apnea") for at least 10 seconds. These repetitive events are associated with collapse of the upper airway during sleep, and may occur 5 to 30 or more times per hour. Although many cases are unrecognized, symptoms may include snoring, fatigue or sleepiness during the day.
OSA afflicts approximately 3% to 7% of the U.S. population. Data from the Wisconsin Cohort Study indicate that the prevalence of OSA in people aged 30-60 years is 9-24% for men and 4-9% for women.
OSA is associated with an increased risk of hypertension, cardiovascular disease, myocardial infarction, stroke and increased mortality.The current standard of care treatment for OSA is "positive airway pressure" (PAP) in which the upper airway is kept open by increased air pressure, but PAP provides benefits only when used consistently. Many patients find PAP to be inconvenient or uncomfortable, and compliance with PAP treatment limits its effectiveness. A safe and effective pharmacologic treatment for OSA could be useful and more acceptable to some patients than PAP, but no drug is currently approved to treat OSA. In the study recently reported in SLEEP, 45 obese adults who were not using PAP were randomized to placebo or treatment with phentermine and topiramate extended-release capsules for 28 weeks. Both groups received intensive lifestyle modification counseling. The primary endpoint was change in the apnea-hypopnea index (AHI), a measure of the average number of breathing interruptions per hour during sleep. An AHI of 5-15 is considered mild, 15-30 moderate, and severe if >30. The average AHI at baseline in both treatment groups was about 45, indicating that, on average, subjects had severe OSA at the beginning of the study. By the end of the study, the number of apnea-hypopnea events in the phentermine and topiramate extended-release capsules group was reduced from an average of 44 events per hour (severe) to 14 events per hour (mild) at Week 28. The placebo-adjusted LS mean change Week 28 was -14.9 (p=0.0084).