These real-world findings confirm that a 156- to 195-unit dose of onabotulinumtoxinA is efficacious and safe, consistent with findings from the PREEMPT clinical trials.
Results from the 2-year, prospective, observational REPOSE (NCT01686581) study indicated that treatment with 156-195 units (U) of onabotulinumtoxinA (Botox; Allergan/AbbVie) was safe and well tolerated in patients with chronic migraine (CM), with similar rates of treatment-emergent adverse events (TEAEs). The data was presented at the 2021 American Headache Society 63rd Annual Scientific Meeting, June 3-6, by Katherine Sommer, PhD, MSc, global medical director, Neurology, Migraine, AbbVie.1
OnabotulinumtoxinA received FDA approval as an injection therapy for the preventive treatment of CM in October 2010, with a recommended dose of 155 units using a sterile 30-gauge 0.5-inch needle.2 In this study, Sommer and colleagues analyzed the real-world safety and efficacy of 156-195 U onabotulinumtoxinA in 77 participants who completed 4 or more treatment visits and matched them to 218 patients who received 155 U for the same number of visits.
In total, 13% (10 of 77) of participants in the 156-195 U group reported TEAEs compared to 23.4% (51 of 218) of participants in the 155 U group. Serious AEs were reported by 1.3% (1 of 77) in the 156-195 U group and 1.4% (3 of 226) of participants in the 155 U group. Notably, there were no new safety signals identified.
Treatment with 156-195 U onabotulinumtoxinA continued to show efficacy, resulting in a change of 8.9 to 17.2 fewer headache days/month across the 10 follow-up time points. In comparison, those in the 155 U group reported a decrease by a range of 8.2 to 13.6 days/month. These differences were deemed not clinically meaningful. Both treatment groups showed increased Migraine-Specific Quality of Life (MSQ) domain scores at all study visits compared with baseline; however, these differences were not clinically meaningful between the groups.
Results of the study were also consistent with the phase 3 PREEMPT trials, which established the safety and efficacy of 155-195 U of onabotulinumtoxinA for the preventive treatment of CM in adults.3 Pooled analyses demonstrated a large mean decrease from baseline in frequency of headache days, with statistically significant between-group differences favoring 156-195 U onabotulinumtoxinA over placebo at week 24 (-8.4 vs -6.6; P <.001) and at all other time points.
Investigators for those studies also noticed significant differences favoring onabotulinumtoxinA for all secondary efficacy variables at all time points, with the exception of frequency of acute headache pain medication intakes. AEs occurred in 62.4% of onabotulinumtoxinA-treated patients and 51.7% if placebo patients, most of which were mild to moderate in severity.
A separate pooled analysis of the PREEMPT trials presented at AHS 2021 also showed that treatment with onabotulinumtoxinA resulted in significantly more consecutive headache-free days and moderate/severe headache-free days than placebo in patients with CM.4 During the double-blind treatment phase, significantly more participants treated with the drug experienced at least 7 or more (74% vs 68%; P = .018), 14 or more (42% vs 34%; P = .003), and at least 21 or more (28% vs 21%; P = .001) consecutive headache-free days without acute medication use.
For more coverage of AHS 2021, click here.