Study Finds Sustained Efficacy of Botox for Migraine Over 3 Years
A response rate of 65% is expected after 3 courses of treatment with onabotulinumtoxin A (Botox) in patients with chronic migraine. Now, a new study has indicated that long-term treatment with onabotulinumtoxin A is effective, safe, and well-tolerated in the patient population.
Building off of a previous study demonstrating the short-term efficacy of the treatment, which is given every 3 months, the study researchers assessed onabotulinumtoxin A in patients who responded to the treatment after 3 sessions. The open-label, single-arm, prospective, observational study followed patients at 5 headache centers around Greece.
“We previously reported that 3 courses of onabotulinumtoxin A prophylactic therapy were able to effectively reduce both the mean headache days/month as well as the days with peak headache intensity >4/10, compared to baseline, in a cohort of 81 patients,” wrote the researchers. “A reduced intake of acute headache medications per month was also apparent.”
The 65 patients who had at least a 50% reduction in mean headache days per month after the 3 sessions were followed for 3 years while taking the treatment. The majority (86.1%) remained on the treatment throughout the study period. Among the 9 patients who dropped out, 5 dropped out due to significant improvement and belief that additional sessions were not needed.
To determine the sustained efficacy of the treatment, the researchers studied changes from the trimester after the third cycle of onabotulinumtoxin A (10 to 12 months [T1]) to the trimester after completing 2 years of treatment (25 to 27 months [T2]) and to the trimester after completing 3 years of treatment (37 to 39 months [T3]).
Between T1 and over 3 years of therapy to T3, there was a significant decrease in mean monthly headache days (7.2 vs 3.4). Similarly, the mean number of monthly days with peak migraine intensity of higher than 4 significantly decreased between T1 and T3 (3.4 vs 2.5). These decreases also led to a significant change in the days of acute headache medication use per month during the time period (4.7 vs 2.8).
“Significant changes towards further improvement occurred in all efficacy variables from T2 to T3, thereby supporting the sustained efficacy of onabotulinumtoxin A consistently administered in a long-term basis,” wrote the authors.
The researchers highlighted that no patient became resistant to the treatment, and the safety analysis showed that it was safe and well tolerated, without severe side effects. However, they noted that a few patients experienced transient and mild adverse events, including wheals in the injection site and shoulder and/or neck pain.
Fifty of the 56 patients that completed the 3 years of treatment continued treatment for additional sessions, and the authors plan to publish the results.
Vikelis M, Argyriou A, Dermitzakis E, et al. sustained onabotulinumtoxin A therapeutic benefits in patients with chronic migraine over 3 years of treatment [published September 17, 2018]. J Headache Pain. doi: https://doi.org/10.1186/s10194-018-0918-3.