Divalproex extended-release in adolescent migraine prophylaxis: Results of a randomized, double-blind, placebo-controlled study

Objective.-To evaluate the efficacy, tolerability, and safety of 3 different doses of divalproex sodium extended-release vs placebo in the prophylaxis of migraine headaches in adolescents. Background.-Divalproex sodium has been approved for migraine prophylaxis in adults, and previous uncontrolled data suggest divalproex sodium may be effective in preventing migraine in children and adolescents with acceptable tolerability. Methods.-This was a 12-week, phase 3, randomized, placebo-controlled, double-blind, parallel-group, multicenter study in approximately 300 adolescents aged 12 to 17 years with migraine headaches. At the end of the baseline phase, subjects still meeting study criteria were randomized in a 1: 1:1:1 ratio to receive divalproex sodium extended-release 250 mg, 500 mg, or 1000 mg once daily, or placebo. The primary efficacy variable was reduction from baseline in 4-week migraine headache rate for each active treatment group vs placebo. Standard safety assessments were conducted and testosterone and sex hormone-binding globulin levels were collected for postmenarchal females. Results.-There was no statistically significant treatment difference between any divalproex sodium extended-release dose group and placebo for the primary efficacy variable, reduction from baseline in 4-week migraine headache rate. There were no statistically significant differences in adverse events between any active treatment group and placebo. A notable dose-related decrease in platelets was observed, and individuals in all 4 treatment groups had increases in ammonia levels; treatment differences in other laboratory variables were generally small. Among postmenarchal female subjects who were not taking hormonal contraceptives or other steroids, there was no statistically significant change in testosterone levels, but a statistically significant dose-related increase in sex hormone-binding globulin was observed. Conclusions.-In the current study, divalproex sodium extended-release did not differentiate from placebo in the prophylactic treatment of migraine headaches but was generally well-tolerated in adolescents aged 12 to 17 years.