Long-term preventive treatment of chronic migraine (CM) with onabotulinumtoxinA (Botox®) effectively reduces the frequency and severity of CM, and is safe and well tolerated over a period of 3 years, according to researchers of a recent study published in the Journal of Headache and Pain.
“Literature contains few studies on the real long-term experience with onabotulinumtoxinA in CM patients,” wrote the authors, led by Michail Vikelis, MD, MSc, PhD, Headache Clinic, Mediterraneo Hospital, Glyfada, Greece. “The majority of those long-term studies have evaluated the results of up to 2 years of treatment.”
OnabotulinumtoxinA is US Food and Drug Administration (FDA) approved for the prophylactic treatment of CM, defined as 15 or more headaches per month, of which ≥ 8 are migrainous or respond to migraine-specific medications.
In their original observational, real-world, open-label, single-arm, non-placebo–controlled core study in 81 CM patients (aged > 18 years), the team found that three courses of onabotulinumtoxinA treatment reduced the frequency of headache days per month and headache days with an intensity of > 4 on a 1-10 numerical scale (moderate/severe pain) compared with baseline.
In this study, the investigators followed the 56 (86.1%) core study responders who experienced a > 50% reduction in average headache days per month for more than 3 years. They found a significant reduction in mean monthly headache days in patients who completed 3 years of treatment compared with those who received only three onabotulinumtoxinA treatments (3.4 vs 7.2 days, respectively; P < 0.001).
During the same period, they also observed a significant drop in mean number of monthly headache days with a peak headache intensity of > 4/10 and in the number of days that patients took acute headache medications per month.
The authors posited that, because patients usually relapse after 1 year of prophylactic onabotulinumtoxinA treatment for CM—particularly in the setting of medication overuse—it is important to assess whether benefits are sustained for at least 3 years of treatment.
“Although there is no consensus on management of responders to onabotulinumtoxinA treatment, the strategy of discontinuing treatment after initial response is often applied with onabotulinumtoxinA treatment,” the researchers wrote. They go on to suggest that with further research, current recommendations may evolve to consider long-term treatment with onabotulinumtoxinA.
“The long-term treatment with onabotulinumtoxinA proved effective, safe, and well tolerated over 3 years,” concluded the authors. “Our findings support the strategy to consistently deliver sessions of use of onabotulinumtoxinA over [a] long time in CM patients.”