GLAXO's IMITREX EFFECTIVE IN TREATING 74% OF CLUSTER HEADACHES

GLAXO's IMITREX EFFECTIVE IN TREATING 74% OF CLUSTER HEADACHES within 15 minutes of treatment compared with a 26% reduction of cluster headaches in patients receiving placebo, according to a study of Imitrex (sumatriptan) published in the Aug. 1 issue of The New England Journal of Medicine. "Seventy-four percent of the patients had a decrease in the severity of headache when their attacks were treated with [6 mg subcutaneous injection of] sumatriptan, whereas 26% had a decrease when they were given placebo," Karl Ekbom, MD, Karolinska Institute, et al. report. "In addition, more patients were free of pain 15 minutes after the injection of sumatriptan than after the injection of placebo (46% vs. 10%)." Glaxo is seeking approval of injectable Imitrex for treating cluster headaches as well as migraines. An NDA was filed in July 1990 covering both indications. The multicenter study of 39 patients consisted of a randomized, double-blind, placebo-controlled crossover design to assess the efficacy of sumatriptan in combating cluster, or Horton's headaches. Patients received a subcutaneous injection of either 6 mg sumatriptan or placebo upon their first headache attack and then were switched to the other treatment for their second headache, which occurred in the next 24 hours to nine days. In addition to reducing pain in more cluster headache attacks, sumatriptan, a serotonin agonist, also had a positive effect on the duration of attacks: 77% of the sumatriptan-treated attacks were fully resolved within 30 minutes of treatment, while only 33% of the placebo-treated attacks were resolved in that time. Adverse events occurred in 35% of the sumatriptan-treated attacks, versus 26% in the placebo-treated headaches. These events were injection-sight reactions and some neurologic symptoms such as dizziness, tiredness, and hot and cold sensations. No one withdrew from the study due to adverse events. A separate article in the same NEJM issue reviews an investigation of sumatriptan's effectiveness against migraine headaches. Michel Ferrari, MD, University Hospital in Leiden, Netherlands, et al., report that a 6 mg dose of sumatriptan reduced pain levels to either "no pain" or "mild pain" in 72% of patients in 60 minutes, while 25% of those receiving placebo experienced similar pain reduction. The study also concluded that the administration of a second dose of the drug an hour after the first dose "affords little additional benefit." The efficacy results of the Ferrari study mirror the findings of another sumatriptan migraine study that appeared in the June 5 issue of the Journal of the American Medical Association. That study, which was also supported by Glaxo and was similar in design to the Ferrari study, found a reduction in pain one hour after administration of the drug in 70% of patients versus only 22% of patients on placebo. An NEJM editorial, by Neil H. Raskin, MD, University of California-San Francisco School of Medicine, includes a comparison of sumatriptan with dihydroergotamine, DHE-45, an FDA-approved migraine treatment marketed by Sandoz. Raskin states that DHE is also "highly effective in aborting migraine attacks," but acts predominantly on different serotonin receptors than does sumatriptan. DHE has been available since the 1950s, but until recently, has not been actively promoted by Sandoz. Due to what the company describes as an "increased awareness of headache," Sandoz "began to consider relaunching DHE some time in the last two years." That effort included a recently released "update" with articles reviewing the product's effectiveness. Sandoz filed an NDA in December 1990 for a nasal spray formulation of DHE.