AMSTERDAM – Researchers are getting a “real-world” view of the use of onabotulinumtoxinA (Botox, Allergan) for chronic migraine (CM) across Europe.
A new post-authorization study shows Botox for chronic migraine is effective with no new safety signals and that about two-thirds of patients are satisfied with the treatment.
The findings were presented here at the Congress of the European Academy of Neurology (EAN) 2017.
For the most part, physicians are following recommended guidelines, Manjit Matharu, PhD, Headache Group, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, UK, told conference delegates.
Botox is approved for CM, but although information on its use for CM is available from clinical trials, there were limited data on utilization patterns and safety in routine clinical practice, said Dr Matharu.
“The question being asked by regulatory authorities was what data are there on the utilization of Botox and its safety in the real world, as opposed to what’s available in clinical trials, which tend to have an artificial setting,” he said.
CM affects 1% to 2% of adults worldwide and has a substantial impact on quality of life.
The recommended treatment paradigm for Botox in CM is based on the two multicenter trials in the Phase 3 Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) clinical program. Each of these studies included a 24-week randomized, double-blind phase followed by a 32-week open-label phase.
The recommended paradigm includes:
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155 U
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A minimum of 31 injection sites across seven specific head/neck muscles
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Up to an additional 40 U using follow-the-pain protocol (maximum of 195 U to 39 sites at the physician’s discretion)
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30-gauge, 0.5-inch needle
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Re-treatment every 12 weeks
Real-World View
The new prospective, observational study included 85 physicians at 58 sites in the UK, Germany, Spain, and Sweden, who attended Allergan-sponsored training sessions.
Physicians had to have an adequate number of adult CM patients eligible for injections in the next 3 to 6 months and be able to host an electronic data collection application.
Dr Matharu noted that decisions to initiate or continue treatment were independent of study participation.
“We told physicians that we just wanted to know what they were doing, not to be guided by the study, but to carry on doing what they were doing.”
Researchers collected data on utilization for up to 52 weeks and on safety for up to 64 weeks.
The analysis included 1160 patients who had at least one treatment. The mean age was 46.6 years, and the cohort was 84.2% women.
Patients reported an average of 7.7 headache-free days per usual month at baseline. About half (50.6%) had previously received Botox for CM.
Physicians administered a total of 4017 treatments over five sessions. The median number of injection sites was 31, which was consistent across all treatment sessions and similar across countries.
“This is exactly what is recommended,” said Dr Matharu.
The median dose (155 U) was also consistent across sessions and generally similar across countries. Dr Matharu noted that there were very few “outliers,” which was also the case for total dose where only a small proportion “are falling off the recommended paradigm.”
Most patients, about 75%, were injected with the appropriate 0.5-inch needle.
Tolerability
For the most part, the mean time between treatment cycles was about 14 weeks, longer than the recommended time interval of 12 weeks.
“Sweden does very well with 12.6 weeks, whereas the UK does worse at 15 weeks,” said Dr Matharu.
Utilization patterns essentially showed that most patients received the recommended number of treatments at the correct dose, he added.
As for tolerability, treatment-related adverse events (TRAEs) were reported by 25% of patients. Such events were less frequent in Spain (11.2%) and most frequent in the United Kingdom (32.7%).
“Nothing fell out that was not known about, and the rates were very similar to what we would expect,” said Dr Matharu.
But there were a few differences. For example, neck pain, the most frequent TRAE, was reported by 4.4% of patients in the current study, compare with 7% in the PREEMPT trial.
The regulatory authority was particularly interested in four possible side effects:
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Dysphagia was reported by 0.3% of patients in the study, but was “self-limiting” in all cases and required no intervention, said Dr Matharu.
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Worsening of migraine (4%).
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Intractable migraine (0.4%).
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Hypersensitivity reactions (0.9%). This included transient rashes, and itching at the injection site, but Dr Matharu noted that most patients who had this side effect went on to get further injections.
About 30% of patients dropped out of the study. More than half did so because of lack of efficacy, 4.4% because of side effects, and another 2.9% were lost to follow-up.
Some 2.4% of patients reported that the treatment was successful but didn’t continue because the headache was episodic and didn’t require further attention.
Overall, most patients (74.4%) were satisfied or extremely satisfied with treatment, but that number may be “biased,” said Dr Matharu.
“You would expect that those already receiving treatments would carry on with them because they were responders.”
Indeed, in that group, the satisfaction rate was 83%.
The “more interesting group,” he said, was the one made up of those naïve to the treatment. In that group, 65.1% said they were satisfied or very satisfied with treatment.
Overall, 12.7% were neither satisfied nor dissatisfied, and 12.9% were dissatisfied or extremely dissatisfied.
Dr Matharu serves on the advisory board for Allergan, St Jude Medical, and Medtronic, and has received payment for the development of educational presentations from Allergan, St Jude Medical, Medtronic, and ElectroCore.
Congress of the European Academy of Neurology (EAN) 2017. Abstract O4108. Presented June 27, 2017.
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