News in brief - March 13, 2006

Clinical trials of multiple sclerosis drug get go-ahead - Birth control patch risks shown - FDA issues approvable letter for weight-loss drug - OTC allergy medication equivalent to prescription drug

Clinical trials of multiple sclerosis drug get go-ahead

The Food and Drug Administration is allowing clinical studies of the multiple sclerosis drug Tysabri, or natalizumab, to go forward, although the drug is not being placed back on the market yet.

Sales of Tysabri were halted in February 2005 after three patients developed PML, or progressive multifocal leukoencephalopathy. Two died.

The removal of the hold on clinical trials allows patients with MS who were previously treated with the drug under an investigational study to resume treatment in an IND study after discussion with their physicians about the potential risks and benefits of treatment, according to the FDA.

Tysabri had been granted accelerated approval by the FDA in 2004 because of its promise at treating flare-ups of multiple sclerosis that occur in the majority of the 400,000 patients diagnosed with this chronic disease.

An FDA advisory committee was scheduled to meet March 7 and 8 to discuss an application for marketing the drug once again.

Birth control patch risks shown

Users of the birth control patch Ortho Evra had an increased risk of developing blood clots compared with women who took birth control pills, according to preliminary results of an epidemiologic study by the manufacturer of the once-a-week patch.

The Food and Drug Administration said it would not take any action yet. "We should caution that these results are preliminary and further evaluation is necessary to understand what these results mean," said Daniel Shames, MD, director of the FDA's division of reproductive and urologic drug products.

The company has conducted two studies to evaluate the risk of serious side effects for patch users. The first found that the risks of thromboembolic events was the same for patch and pill users. Ongoing evaluation also suggests that there is no difference in the risk of heart attack or stroke.

The second study, which is still being evaluated, has shown a two-fold increase in the risk of venous thromboembolic events for patch users. The study also shows that risks of heart attack and stroke are apparently similar for users of each product.

FDA issues approvable letter for weight-loss drug

The Food and Drug Administration has issued a letter to Sanofi-Aventis stating that rimonabant is approvable for weight loss but not approvable for smoking cessation, according to a February statement by the company.

The drug is the first of the new selective cannabinoid-1 receptor blocker class of medications. Generally positive results from trials looking at its effectiveness have trickled out over the past couple years. Most recently, the Feb. 15 Journal of the American Medical Association published results from the large-scale RIO-North America trial.

More than 3,000 obese patients received either placebo or various doses of the drug over two years. Those who took 20 mg and dieted lost approximately five kilograms more than those who took the placebo. Triglycerides and high-density cholesterol also declined more significantly in the group that received the drug.

Researchers concluded that the drug was effective but expressed concern because the dropout rate for all arms of the trial hovered around 50%.

OTC allergy medication equivalent to prescription drug

The over-the-counter decongestant pseudoephedrine is equally effective to the prescription drug montelukast at relieving the symptoms associated with ragweed allergy, according to a study published in the February Archives of Otolaryngology -- Head & Neck Surgery.

Researchers randomized 58 adults with confirmed ragweed allergic rhinitis to receive either 240 mg of pseudoephedrine or 10 mg of montelukast sodium daily for two weeks.

Patients kept diaries of their symptoms and completed quality-of-life questionnaires at the beginning and end of the trial.

Both treatments improved symptoms and quality of life, although pseudoephedrine was more effective for nasal congestion.

The authors concluded that these two drugs were equivalent but are calling for larger trials that might find more adverse events.

"These agents appear equivalent for the treatment of seasonal allergic rhinitis," wrote the authors. "A larger study may have shown a difference in the adverse effect profile."