Dr Jan Lewis BrandesJan Lewis Brandes, MD, MS
New data suggest that patients with chronic migraine treated with erenumab (Aimovig; Amgen) who had a response rate of ≥50% experienced a reduction in monthly migraine days that was nearly double that of the overall population.1

The 667-patient cohort was randomized 3:2:2 to placebo (n = 281), erenumab 70 mg (n = 178), or erenumab 140 mg (n = 182), and ultimately, 23.5% (n = 66) of the placebo experienced ≥50% response compared to 39.9% (n = 75) and 41.2% (n = 77) of patients on erenumab 70 and 140 mg, respectively, at month 3.

The proportion of patients achieving ≥50% response in ≥1  of the 3 monthly treatment periods in the placebo, erenumab 70 mg, and 140 mg groups were 30.6%, 57.4%, and 54.0%, respectively.

Study author Jan Lewis Brandes, MD, MS, founder, Nashville Neuroscience Group, and assistant clinical professor of neurology, Vanderbilt University School of Medicine, and colleagues wrote that “these findings may help to provide context for setting realistic patient expectations regarding the spectrum of response that may be attained at the individual patient level during treatment with erenumab, and for those who respond to treatment, the greater therapeutic gain that may be achieved.”
 
READ MORE: Ubrogepant Safety Reaffirmed Over Long-Term Intermittent Use

All told, the likelihood of achieving ≥50% reduction from baseline migraine days at month 3 was significantly greater in those on erenumab compared with placebo, at both the 70 mg (odds ratio [OR], 2.2; 95% CI, 1.5–3.3; P <.001) and the 140 mg dose (OR, 2.3; 95% CI, 1.6–3.5; P <.001).

Similar to the ≥50% responders, the rates of ≥75% responders were quite high, with 17% (n = 32) and 20.9% (n = 39) of the 70 mg and 140 mg groups, respectively, achieving that level of response compared to only 7.8% (n = 22) of those in the placebo group. In total, 12.8% of placebo patients compared to 25% and 27.3% of those in the 70 mg and 140 mg groups achieved ≥75% response in ≥1 treatment period. As such, the odds of achieving that reduction were also significantly greater with erenumab 70 mg (OR, 2.4; 95% CI, 1.4–4.3; P = .002) and 140 mg (OR, 3.1; 95% CI, 1.8–5.5; P <.001) compared with placebo.

“Not all patients in the study experienced monthly migraine days reduction, and in fact, ~20% of patients across treatment groups did not demonstrate any improvement, a result that is consistent with other placebo-controlled migraine prevention trials,” Brandes and colleagues wrote. “A challenge for future research is to identify predictors of response/nonresponse to a given preventive treatment.”
Compared with the overall erenumab-treated population—whose change in monthly migraine days was 6.6 at both doses—≥50% responders showed reductions of 12.2 days and 12.5 days for 70 mg and 140 mg, respectively, compared to 2.6 days and 2.2 days, respectively, for those not achieving that response. For those achieving ≥75% response, those reductions were 13.9 days and 14.8 days, versus 5.0 days and 4.3 days for those who did not.

“This highlights the rather wide spectrum of response to treatment and emphasizes that mean results for an overall study population will underestimate the actual benefit achieved in the subgroup of patients who are deemed responders,” Brandes et al. noted.

The calcitonin gene-related peptide (CGRP) inhibitor was first approved by the FDA for the prevention of migraines, as a once-monthly self-injectable. In the pivotal phase 3 trial, STRIVE, a ≥50% reduction in migraine days per month was achieved for nearly half of patients treated with erenumab (70 mg: 43.4%; 140 mg: 50.0%) compared with just 26.6% with placebo (P <.001).2

Additionally, recent results from a small, single-center, 7-patient study showed that those with posttraumatic migraine headache experienced a statistically significant reduction in monthly headache days—with a 95% reduction after 2 months (SD, 1.22; P <.001) when treated with erenumab.3
REFERENCES
1. Brandes JL, Diner HC, Dolezil D, et al. The spectrum of response to erenumab in patients with chronic migraine and subgroup analysis of patients achieving 50%, 75%, and 100% response. Cephalagia. Published online December 9, 2019. doi: 10.1177/0333102419894559.
2. Goadsby PJ, Reuter U, Hallström Y, et al. A Controlled Trial of Erenumab for Episodic Migraine. N Engl J Med. 2017; 377:2123-2132. doi: 10.1056/NEJMoa1705848.
3. Charles JA. Treatment of posttraumatic headache migraine phenotype with erenumab- an observational study. J Concussion. 2019; 3(1-4). doi:10.1177/2059700219878292.