Erenumab works well in chronic migraine patients across Asia

Erenumab proves to be effective at lowering the number of monthly migraine days in Asian patients with chronic migraine while having a favourable safety profile, according to the results of DRAGON study.

“DRAGON is the first study of erenumab conducted in patients with chronic migraine from Asia. This phase III study met the primary endpoint of change from baseline in monthly migraine days (MMD) during the last 4 weeks of the 12-week treatment period,” the investigators said.

Compared with placebo, once-monthly subcutaneous injections of erenumab 70 mg yielded a greater decrease in MMD (–8.2 vs –6.6 days; adjusted mean difference, −1.57 days, 95 percent confidence interval [CI], − 2.83 to − 0.30; p=0.015). The advantage with erenumab was evident at all assessment time points, from the first assessment at week 4 and sustained throughout the study. [J Headache Pain 2022;23:146]

Furthermore, significantly more patients on erenumab achieved ≥50-percent reduction in MMD (47.0 percent vs 36.7 percent; p=0.014). The decline in MMD occurred in parallel with reductions in monthly acute headache medication days (−5.34 vs −4.66) and modified migraine disability assessment (mMIDAS) scores (−14.67 vs −12.93), both of which were greater with erenumab vs placebo.

Overall, there was high treatment compliance among patients, with the majority (98.0 percent) receiving three doses of the study drug as planned, as noted by the investigators. Safety and tolerability profile of erenumab did not differ from that of placebo, except the incidence of constipation (8.6 percent with erenumab vs 3.2 percent with placebo).

The present data are consistent with the findings from the global pivotal chronic migraine study, which showed that erenumab at either 70  or 140 mg led to a reduction in MMD at week 12 of 6.6 days as opposed to only 4.2 days with placebo (treatment difference, −2.5 days). [Lancet Neurol 2017;16:425-434]

Of note, the greater MMD reductions in both treatment arms in the DRAGON study than in the global pivotal chronic migraine study may reflect the greater so-called ‘placebo effect’ in the Asian population, given that “migraine-specific medication for acute treatment is not widely available in Asian countries, thus patients are more often treated with general painkillers,” according to the investigators.

They also pointed out that the higher placebo effect observed had no substantial effect on the treatment benefit obtained with erenumab 70 mg.

“In migraine prevention trials, a high variability in placebo effect is observed, and there is a need for data on the ethnocultural differences in the placebo effect in migraine prevention. However, the timing of drug trials, not ethnic differences, may play a role, as most of the multinational trials are performed in the Western countries first, then followed by Asian trials. Consequently, strong efficacy evidence based on a large number of prior successful trials may increase the expectations of both patients and physicians,” the investigators explained. [Headache 2020;60:1542-1557]

The study had several limitations. First, aura status was self-reported rather than diagnosed by a physician, which could lead to a misrepresentation of the prevalence of migraine with aura because many patients seem to confuse the prodromal symptoms with the aura symptoms. Second, the definition of a migraine day used in the DRAGON study differed from the widely accepted definition that includes migraine-specific medication only.

Despite these limitations, “the study was designed with sufficient power to account for the high proportion of treatment-naïve and medication-overuse patients, the high placebo effect in the Chinese/Asian population, and the potentially larger variance in this multiple-national study,” the investigators said.