[Botulinum toxin type A (Relatox) in transition from medication overuse to non-overuse status in patients with chronic migraine: a subgroup analysis of phase IIIb randomized single-blind multicenter active-controlled parallel-group trial].

[OBJECTIVE] To access the effect of Relatox, the first Russian botulinum toxin type A, in patients with chronic migraine (CM) and medication overuse (MO).

[MATERIAL AND METHODS] In phase IIIb single-blind randomized multicenter active-controlled parallel-group study, patients with CM were randomized to once intramuscular injections of Relatox (101) or onabotulinumtoxin A injections - Botox (108). This subgroup analysis evaluated the percentage of patients who transition from medication overuse to non overuse status from baseline; mean changes in the number of headache days, migraine headache days, acute headache medication intakes days, headache intensity, proportion of patients who had a ≥50% reduction in headache days, proportion of the patients with severe (≥60) Headache Impact Test-6 score and with a severe (≥21) MIDAS score in a 28-day periods in each treatment among patients with baseline acute medication overuse via repeated measures.

[RESULTS] Of 209 patients with CM, 100% met medication overuse criteria. Relatox and Botox demonstrated significant improvement for overall least squares mean change in headache days, migraine headache days, headache intensity; and headache-related disability and quality of life in CM patients with baseline MO, without differences between the groups. 75% and 70% patients in the Relatox and Botox groups, respectively, achieved ≥50% reduction in headache days from baseline (OR 1.58, CI 95% 0.84; 3.02, =0.155). Furthermore, Relatox and Botox significant reduced average medication overuse rates in patient with CM and MO at baseline. 62% of patients in the Relatox group and 48% of patients in the Botox group transitioned from medication overuse to non overuse status compared from baseline (OR 2.07, CI 95% 0.91; 4.62, =0.044). Relatox group had greater reductions than the Botox group in the percentage of patients with acute migraine-specific medication (triptan) overuse (=0.050).

[CONCLUSION] The results demonstrate highly prevalent of medication overuse among individuals with CM. This analysis provides evidence that the Russian botulinum toxin type A Relatox significantly improves measures of headache symptoms, quality of life and headache-related disability, and also significantly greater, compared to Botox, reduces migraine-specific medication consumption in patients with chronic migraine who overuse acute medications.