BERLIN – Rizatriptan fought migraine more effectively in children and adolescents when it was dosed according to body weight in a randomized, double-blind parallel group trial.
Previous industry-sponsored rizatriptan studies in children revealed no significant treatment effects, Dr. Tony W. Ho said. For example, in one study of 291 adolescents, the 2-hour response rate was 66% with treatment versus 56% with placebo. The lack of significant efficacy could be due to all patients receiving the same 5-mg tablets, a dose that can be insufficient given the increase in body mass index among 12- to 17-year-olds, he added.
"If you think about it, many adolescents are as heavy as some adults nowadays but may receive a lower dose," said Dr. Ho, a researcher at Merck Sharp & Dohme Corp., Whitehouse Station, N.J., a subsidiary of Merck & Co., which markets rizatriptan as Maxalt.
In the current study, Dr. Ho and his associates tried weight-based dosing in children aged 12-17 years with a history of moderate to severe attacks. Those who weighed less than 40 kg received 5-mg of rizatriptan orally disintegrating tablets (ODT; Maxalt-MLT), and those 40 kg or heavier received 10 mg within 30 minutes of a moderate to severe attack.
"These teenagers were heavier than we expected, with a mean BMI of 22.6 [kg/m2]. The majority of patients were from the U.S.," Dr. Ho said at the International Headache Congress, which was sponsored by the International Headache Society and the American Headache Society.
A total 570 of the 702 participants were evaluable for efficacy analyses and were studied further. The researchers found 31% of the treatment group (87 of 284 participants) reported freedom from pain at 2 hours (the primary outcome), compared with 22% (63 of 286) of the placebo group. The odds ratio favoring rizatriptan was 1.55. Patients rated their pain from 1 (a happy face meaning no head pain) up to 5 (a frowning face reflecting very bad head pain).
"Weight-based rizatriptan ODT treatment demonstrated a statistically significant difference versus placebo in eliminating pain," Dr. Ho said.
The study featured a double-blind, run-in phase design. "Even with a design to reduce the placebo effect, we still had a 22% rate," Dr. Ho said.
Patients randomized to rizatriptan also experienced significantly less nausea, vomiting, and impairment of activities of daily living, compared with those who received placebo, Dr. Ho said. "This supports a weight-based approach to treating pediatric migraine."
A meeting attendee questioned the incidence of vomiting reported in the study, stating that "usually the rate of severe vomiting is 60%-70%, but you had lower than 15%."
The children rated severity of associated symptoms, including vomiting, using a five-face scale, Dr. Ho replied. "I don’t know how that is related to other definitions of severity."
There was no statistically significant difference in 2-hour pain relief, a secondary outcome experienced by 59% of the treated group and 51% of the placebo group.
Rizatriptan use is off label in pediatric patients. The Food and Drug Administration cleared this selective 5-hydroxytryptamine1B/1D receptor agonist for acute treatment of migraine attacks with or without aura in adults 18 years and older.
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