[Botulinum toxin type A (Relatox) in the treatment of chronic migraine in adults: results of phase IIIb, randomized, one-blind, multicenter, active-controlled, parallel-group trial].

Objective: To access the efficacy and safety of the first Russian botulinum toxin type A (Relatox) as a headache prophylaxis in adult with chronic migraine (CM).

Material and methods: The randomized, one-blind, multicenter, active-controlled, parallel-group trial study involved 209 patients with CM aged from 19 to 65 years. The patients were randomized to injections of the Russian botulinum toxin type A - Relatox (n=101) or onabotulinumtoxinA injections - Botox (n=108). The duration of the study was 16 weeks, which included five visits of patients every 4 weeks. Relatox and Botox were injected once into seven muscle groups of the head and neck at a dose of 155-195 units. Primary efficacy variable was mean change from baseline in frequency of headache days after 12 weeks. Secondary efficacy variables were mean changes from the baseline to week 12 in frequency of migraine days, acute headache pain medication intakes days; headache intensity; proportion of patients achieving ≥50% reduction from baseline in headache days, the proportion of the patients with medication overuse, the proportion of the patients with severe (≥60) Headache Impact Test-6 score and with a severe (≥21) MIDAS score.

Results: Analyses demonstrated a large mean decrease from baseline in frequency of headache days, without statistically significant between-group differences Relatox vs Botox at week 12 (-10.89 vs -10.06; p=0.365) and at other time points. Significant differences from baseline were also observed for all secondary efficacy variables at all time points without differences between the groups. The proportion of patients achieving ≥50% reduction from baseline in headache days was 75.0% and 70% in the Relatox and Botox groups, respectively (OR, CI 95% 1.58 [0.84; 3.02], p=0.155). Adverse events (AE) occurred in 15.8% of Relatox patients and 15.7% of Botox patients (p=1.000). No unexpected AE were identified.

Conclusion: The results demonstrate that the first Russian botulinum toxin type A (Relatox) is an effective prophylactic treatment for CM in adult patients. Relatox led to significant improvements from baseline in multiple measures of headache symptoms, headache-related disability and quality of life. For the first time, a comparative analysis of two botulinum toxin type A products in parallel groups showed no less (not inferior) efficacy and safety of Relatox relative to Botox in the treatment of CM in adults.