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 (n=101) or onabotulinumtoxin A injections — Botox (n=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, p=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, p=0.044). Relatox group had greater reductions than the Botox group in the percentage of patients with acute migraine-specific medication (triptan) overuse (p=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.