Heidi Moawad MD
The recent 3-month double-blind study by Schwedt and colleagues included 580 participants and compared the effects of galcanezumab (Emgality) with those of rimegepant (Nurtec ODT). These medications are administered by different methods when used for migraine prevention; galcanezumab is given subcutaneously (SC) every month, whereas rimegepant is taken by mouth every other day. To blind the study, participants were randomly assigned to receive either 120 mg galcanezumab SC per month (after a 240 mg loading dose) and a placebo oral disintegrating tablet every other day or every-other-day 75 mg rimegepant as oral disintegrating tablets and a monthly SC placebo. According to the study authors, 62% of the patients receiving galcanezumab vs 61% of those receiving rimegepant achieved ≥ 50% reduction in monthly migraine headache days after 3 months, with no statistically significant difference between the groups. Comparisons between CGRP receptor antagonists are scarce. The studies tend to be of a short duration and to include small sample sizes — and most are retrospective. To date, physicians who treat patients with these drugs do not have information about the distinguishing characteristics between these treatments that could be used to guide drug selection for subtypes of migraine or different patient populations. As further research emerges, we may see distinctions between these therapies, or we might continue to see that their effects are similar in terms of benefits, duration of action, and patient characteristics.
Many patients who are prescribed these new medications have already been treated with a variety of other previously available migraine therapies, with varying degrees of improvement. Physicians who prescribe treatments for migraine patients often move on to new therapeutic options when patients only experience partial relief, but recent research suggests that even these incomplete responses could be beneficial for patients.
Researchers at the Headache Centre — Neurology Clinic at the Spedali Civili di Brescia in Brescia, Italy, conducted a retrospective study to examine whether previous treatment with onabotulinumtoxinA affected patent response to anti-CGRP mAb (Ceccardi et al). These treatments have differing mechanisms. OnabotulinumtoxinA is an exotoxin produced by Clostridium botulinum that blocks the acetylcholine release from nerve endings temporarily disabling postsynaptic action. Anti-CGRP mAb work by inhibiting the inflammatory receptor, thereby inhibiting the pain sensation.2
Several studies have examined the effects of combining onabotulinumtoxinA (Botox) with anti-CGRP mAb, with varying results. For example, researchers of a study designed to compare the two treatments concluded, "In patients with chronic migraine who have only had a partial response to Botox, adjunctive preventative therapy with a CGRP-mAb drug is safe and effective."2 A review examining several small studies that evaluated the response of dual therapy included a few studies that found no significant differences between an anti-CGRP mAb monotherapy and dual therapy with onabotulinumtoxinA, as well as some studies that noted improvement with dual therapy over either therapy alone. The review authors concluded that a real-life application is not yet determined and that "Further sufficiently powered, placebo-controlled studies are warranted to shed light on potential additive or synergistic effects of combining onabotulinumtoxin A with a CGRP antagonist."3
The Brescia study was designed to examine the effect of previous onabotulinumtoxinA treatment on subsequent anti-CGRP mAb response. The researchers enrolled 128 patients, of whom 51 (39.9%) had previously been treated with onabotulinumtoxinA, with the last dose 3 months before preventive treatment with an anti-CGRP mAb was started. The study was conducted between November 2018 and May 2023. The outcomes noted included monthly headache days, monthly migraine days, mean analgesic consumption, and clinical disability according to the Migraine Disability Assessment test (MIDAS). Participants received 3 months of treatment with an anti-CGRP mAb.
In addition to comparing patients who had previously received onabotulinumtoxinA with those who did not, the researchers also "aimed to evaluate whether the clinical response to anti-CGRP mAb was affected by the number of previous Onabotulinumtoxin-A administrations.
The documented baseline prior to treatment with an anti-CGRP mAb was as follows: mean monthly headache days 23.7 (SD 5.7), monthly migraine days 13.9 (SD 8.0); mean MIDAS score 108.9 (SD 76.1); and mean analgesic consumption 24.8 (SD 18.8). After 3 months of treatment with an anti-CGRP mAb, both groups experienced significant improvement in all these parameters. Furthermore, after 3 months of treatment with an anti-CGRP mAb, the patients who received at least three onabotulinumtoxinA administrations prior to the study experienced lower MMD compared with those who had received fewer cycles.
For physicians and patients, this outcome provides validation that patients can potentially gain long-term benefits from migraine treatment, even if such interventions do not provide sufficient migraine relief. The conclusion cannot be generalized to other migraine treatment sequences, and the authors did not suggest deliberately postponing any treatment or using any treatment as "priming" for another treatment. Yet physicians may be able to give patients some reassurance that an incomplete response in migraine therapy is not futile.
Migraine treatment can be very effective, but sometimes it is not clear whether patients should take their medication before or during a migraine episode, or whether the signal to take medication should be based on specific symptoms. Many patients wait to take their migraine treatment until they are sure that they will have a migraine, especially if they frequently have prodromal symptoms that do not consistently lead to a migraine. Additionally, some of the new CGRP receptor antagonists are expensive, and many payers only approve a limited amount per month. Patients might not want to waste their CGRP receptor antagonist supply in case they run out before their next refill authorization.
AbbVie, the makers of ubrogepant (Ubrelvy), a CGRP receptor antagonist approved for acute treatment of migraine, conducted a phase 3, multicenter, randomized, double-blind, placebo-controlled, crossover trial of ubrogepant at 75 research centers and headache clinics in the US (Dodick et al). According to the manufacturer, the aim of the trial was to evaluate the efficacy, safety, and tolerability of 100 mg ubrogepant for the acute treatment of migraine when administered during the prodrome of a migraine attack. The study included 518 participants age 18-75 years who had at least a 1-year history of migraine and had had two to eight migraine attacks per month that included symptoms of a moderate to severe headache in each of the 3 months before the study. Because this was a crossover trial, the participants were randomly assigned to either receive placebo for treatment of the first qualifying prodrome event and 100 mg ubrogepant for treatment of the second qualifying prodrome event or to receive 100 mg ubrogepant to treat the first qualifying prodrome event and placebo to treat the second qualifying prodrome event.
According to AbbVie's news release following publication of the study, "Absence of moderate or severe intensity headache within 24 hours was achieved following 46% of qualifying prodrome events when treated with UBRELVY vs 29% of placebo-treated events" and "absence of moderate or severe intensity headache within 48 hours was achieved following 41% of qualifying prodrome events when treated with UBRELVY vs 25% of placebo-treated events" (both P < .0001).4 Safety and tolerability of treatment during the prodromal period were also established.
In clinical practice, these results hold promise because patients can gain some assurance in knowing that taking their migraine treatment during their early prodromal symptoms is safe and could potentially improve the outcome of the event, preventing migraine symptoms for 48 hours. Even for patients who do not have an ample supply of ubrogepant or another CGRP antagonist, taking a treatment that is approved by their doctor at the onset of prodromal symptoms can provide relief compared with waiting until symptoms worsen.
Additional References
1. Waliszewska-Prosół M, Vuralli D, Martelletti P. What to do with non-responders to CGRP(r) monoclonal antibodies: Switch to another or move to gepants? J Headache Pain. 2023;24:163. doi: 10.1186/s10194-023-01698-8
2. Pallapothu MR, Quintana Mariñez MG, Chakkera M, et al. Long-term management of migraine with OnabotulinumtoxinA (Botox) vs calcitonin gene-related peptide antibodies (Anti-CGRP). Cureus. 2023;15:e46696. doi: 10.7759/cureus.46696
3. Pellesi L. Combining onabotulinumtoxin A with a CGRP antagonist for chronic migraine prophylaxis: Where do we stand? Front Pain Res (Lausanne). 2023;4:1292994. doi: 10.3389/fpain.2023.1292994
4. AbbVie. Results published in The Lancet show UBRELVY® (ubrogepant) reduces the headache phase of a migraine attack when dosed during the prodrome of migraine. November 16, 2023. Source