GLAXO PLANS JUNE NDA FILING FOR ANTI-MIGRAINE AGENT SUMATRIPTAN; ORAL WILL FOLLOW FILING FOR SUBCUTANEOUS FORM; 50% RESPONSE RATE FOUND AFTER 30 MINUTES
Glaxo plans to file NDAs worldwide (except in Japan) "in the next few weeks" for sumatriptan, its anti-migraine agent, the company told securities analysts in New York City May 31. Filings are planned for both the subcutaneous and oral forms of the 5HT-1-like agonist for both migraine and cluster (Horton's) headaches. The NDA will include data from double-blind, placebo-controlled and comparative trials on more than 7,000 patients, Glaxo said. Sumatriptan (GR-43175) is derived from the company's research on the 5-hydroxytryptamine (5HT) serotonin receptors. Glaxo also plans to register the drug for approval in the U.K. this year. A follow-up compound for migraine has entered exploratory development, the company said. Glaxo Director of Clinical Research, Cardiovascular, Michael Tansey told the New York meeting that over 3,000 patients had participated in controlled trials of subcutaneous sumatriptan, with over 600 patients participating in a study versus placebo. In the comparative study, "patients tend[ed] to feel better almost immediately," Tansey said. Fifty percent of those who were injected with sumatriptan responded within 30 minutes -- with response defined as little or no headache or some headache -- and by 90 minutes, Tansey said, over 80% of the sumatriptan group responded. He noted that this response is seen across sequential attacks, whether the attack is a "classical" or "common" migraine, and at whatever stage the migraine is treated. Tansey described sumatriptan's side effects as "very mild" and "self-limiting." Subcutaneous sumatriptan produced side effects in 39-55% of patients compared to 19-35% on placebo in the trial. Within 45 minutes, the adverse event profile of patients on sumatriptan is the same as that with placebo. One side effect is transient stinging at the injection site. Patients who administered the drug themselves with a pre-filled syringe in an auto-inject pen had a lower incidence of stinging, he noted. Other symptoms, which are "very trivial and very short lived," according to Tansey, include a feeling of warmth, dizziness, vertigo, malaise and fatigue. During Q&A, Tansey dismissed the idea that a patient with severe migraine could overdose on self-injected sumatriptan. "We have never encountered a severe toxicity problem in the clinicals," he said, noting that the trials had used doses of up to 16 mg/day. Glaxo is recommending 6 mg as a single dose with a maximum per day of 12 mg. Glaxo tested the oral formulation in over 1,500 patients in controlled studies. The response is "very comparable" to subcutaneous sumatriptan, Tansey said, as is the side effect profile. "There is only one difference and that is the time scale...The time of the onset and peak is two and four hours, respectively...The effect is generally in one hour." The recommended dose is 100 mg. He suggested that people may prefer to use the oral formulation over the subcutaneous in several instances. The oral dose would be appropriate for those who can anticipate a migraine attack (e.g., those who experience an aura before an attack) and those with relatively mild headaches or who do not suffer from nausea or vomiting when having an attack. Sumatriptan also appears to provide the only effective treatment for cluster (or Horton's) headaches, an extremely severe form of headache occurring in 400,000-500,000 people in the U.S., Glaxo told the analysts. Five times as many males suffer from cluster headaches than females, who tend to suffer more from classical or common migraine. Tansey described the attacks as usually occurring once or twice a day for weeks or months at a time and lasting for 30-120 minutes, although some cluster headaches are chronic. Glaxo started a double-blind crossover study of subcutaneous sumatriptan in patients who were categorized as having severe or extremely severe headaches. "By 15 [minutes after injection], they had reached a level where they could function normally or with only mild residual symptoms," Tansey reported.
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