Wearing Off Response to OnabotulinumtoxinA in Chronic Migraine: Analysis in a Series of 193 Patients

Synergism of Anti-CGRP Monoclonal Antibodies and OnabotulinumtoxinA in the Treatment of Chronic Migraine: A Real-World Retrospective Chart Review

BACKGROUND

Many patients with chronic migraine do not achieve clinically meaningful improvement in their headache frequency with monotherapy. The burden associated with chronic migraine calls for a multifaceted treatment approach targeting multiple aspects of migraine pathophysiology.

OBJECTIVE

The aim of this study was to evaluate the effect of concurrent anti-calcitonin gene-related peptide (CGRP) monoclonal antibody (mAb) and onabotulinumtoxinA (onabot) treatment on median monthly migraine days (MMD) in patients with chronic migraine, through a retrospective study.

METHODS

The electronic medical records of Cleveland Clinic patients either concurrently (dual therapy) or consecutively (monotherapy) treated with anti-CGRP mAbs and onabot between June 2018 and November 2021 were extracted. Only adult patients (≥ 18 years of age) were included in this study. MMDs for 194 concurrently treated (86.6% female and a median [interquartile range] age of 51 [41-61] years) and 229 consecutively treated (88.2% female and median age of 47 [IQR 39-57] years) patients were examined at baseline, after first therapy of either anti-CGRP mAb or onabot, and following dual therapy for 3 consecutive months. The reduction of MMDs for each treatment group were compared. The same approach was utilized to compare consecutive monotherapy at separate times (n = 229) and dual-therapy groups.

RESULTS

The initial treatment of the dual-therapy group reduced the median (IQR) MMDs from 30 (30-30) to 15 (12-30) [p < 0.0001]. After initiation of dual therapy, the median MMDs was further decreased from 15 (12-30) to 8 (3-22) [p < 0.0001]. A majority [132/194 (68.0%)] of the dual-therapy patients reported a ≥ 50% reduction in MMD and 90/194 (46.4%) reported a ≥ 75% reduction. For the consecutive monotherapy group, median MMDs changed from a baseline of 30 (25-30) to 15 (8-25) from onabot monotherapy and decreased from 25 (15-30) to 12 (4-25) after anti-CGRP mAb monotherapy. Almost half (113/229 [49.3%] from onabot, and 104/229 [45.4%] from anti-CGRP mAb) of these patients achieved a ≥ 50% reduction in MMDs and a minority (38/229 [16.6%] from onabot, and 45/229 [19.7%] from anti-CGRP mAb) achieved a reduction of ≥ 75%. Additionally, dual therapy showed significant improvement in MMDs compared with monotherapy of either treatment (p < 0.0001).

CONCLUSION

Dual therapy of anti-CGRP mAbs and onabot may be more efficacious than monotherapy, possibly due to their synergistic mechanisms of action.

Early Wearing-Off Effect of OnabotulinumtoxinA in Chronic Migraine: A Prospective Real-Life Study

OBJECTIVE

Chronic migraine (CM) is a significant public health problem that affects 2.2% of the global population. Onabotulinumtoxin A (OnabotA) is a safe and effective prophylactic treatment for patients with CM. The standard injection interval for OnabotA is 12 weeks. Nevertheless, some patients experience a wearing-off effect (WOE) in the weeks preceding the next scheduled cycle. The objectives of this study are to determine the prevalence of early WOE, to analyze variables that could be clinical predictors and to specify which interval is the most appropriate to define the existence of this phenomenon.

METHODS

This is a prospective single-center study of consecutive adult patients with CM who, after failing previous prophylactic therapies, started OnabotA treatment following the PREEMPT protocol between June and December of 2021.

RESULTS

A total of 59 patients (93.2% female, age 44 ± 12 years) were included. A total of 37 patients (64.9%) fulfilled medication overuse criteria. Of the total patients, 40.6% reported WOE and this was more frequent after the first cycle (35.6%). Depression and anxiety disorder was a statistically significant clinical predictor of WOE (OR 3.4; CI 95% 1.22-10.84; p = 0.028). A better cut-off point to consider WOE seems to be at 10 weeks.

CONCLUSIONS

Early WOE is common in patients on OnabotA treatment for CM. Individualizing the standard 12-week injection, using total doses of 195 U, and managing psychiatric comorbidities with pharmacological and non-pharmacological strategies may improve treatment outcomes and reduce OnabotA WOE.

"Wearing-off" efficacy of CGRP monoclonal antibodies for migraine prevention: A meta-analysis of randomized controlled trials

BACKGROUND

A new migraine prevention, CGRP monoclonal antibodies (mAbs), is injectable on a monthly or quarterly basis. In clinical practice, some patients reported that drug effectiveness does not last until the upcoming scheduled injection, a so-called "wearing-off" effect. We aimed to evaluate the wearing-off effect of the CGRP mAbs for migraine prevention in patients with different monthly migraine days.

METHODS

We conducted a literature search for studies that reported migraine frequency after CGRP monoclonal antibody administration from MEDLINE, SCOPUS, Web of Science, and Cochrane Database from inception through February 2022. A meta-analysis, random-effects model was applied to assess the difference in migraine frequency between early and later weeks after medication to assess the presence of a wearing-off effect. Risk ratio was calculated to report the pooled treatment effect.

RESULTS

Four studies were entered for the analysis, comprising 2409 patients in randomized controlled trials. There was no association between CGRP mAbs and wearing-off effect in patients with galcanezumab with a pooled risk ratio of 1.29 (95% CI 0.73 to 2.28) compared to placebo group. However, there was an association between galcanezumab and wearing-off effect in patients with chronic migraine with a pooled risk ratio of 1.91 (95% CI 1.11 to 3.28) compared to placebo group.

CONCLUSION

In this meta-analysis, there was a wearing-off efficacy of galcanezumab but only in a small percentage of patients with chronic migraine in randomized controlled trials.

Post hoc analysis of clinical trial data and pharmacokinetic data to assess wearing-off of erenumab within monthly treatment cycle

BACKGROUND

Treatment wearing-off has been reported for calcitonin gene-related peptide-pathway monoclonal antibodies, including erenumab, specifically in the last week of the monthly dosing cycle.

OBJECTIVE

We sought to determine the consistency of erenumab effect throughout the monthly treatment cycle.

METHODS

In this post hoc analysis of four pivotal double-blind, randomized controlled studies of erenumab in episodic and chronic migraine, we assessed wearing-off based on change in weekly migraine days at week 4 versus average over weeks 1-3 in each monthly dosing cycle. Analyses were conducted at each monthly dosing cycle in all patients, in responders (≥50% reduction in weekly migraine days), and in consistent responders (response in ≥2monthly cycles).

RESULTS

There was no evidence of wearing-off in the full study populations of two global studies (N = 946 and N = 656) and two Japan studies (N = 475 and N = 261). In the full study population, mean change in weekly migraine days at week 4 compared with the average over week 1-3 ranged from 0.15 days improvement to 0.19 days worsening in the placebo group and 0.08 days improvement to 0.20 days worsening in the erenumab groups. A subgroup of responders experienced wearing-off, but the extent of wearing-off did not differ between erenumab and placebo groups. The mean change in weekly migraine days at week 4 compared with the average over weeks 1-3 ranged from 0.34 to 0.61 days worsening in the placebo group and 0.27 to 0.78 days worsening in the erenumab groups. Few patients had persistent wearing-off in ≥2 consecutive monthly treatment cycles. For erenumab-treated responders, serum erenumab concentrations were similar among patients experiencing wearing-off and those maintaining response.

CONCLUSION

No systematic wearing-off with erenumab was identified. Further research is needed to determine if wearing-off reported for some patients in clinical practice reflects a true treatment response pattern or normal fluctuations in migraine frequency.

OnabotulinumtoxinA: Still the Present for Chronic Migraine

OnabotulinumtoxinA (BT-A) is one of the few drugs approved for the preventive treatment of chronic migraine (CM). Despite this, some aspects of its mechanism of action are still a matter of debate, and the precise magnitude of BT-A effects needs to be completely elucidated. BT-A acts primarily upon trigeminal and cervical nerve endings, by inhibiting the release of inflammatory mediators such as calcitonin gene-related peptide, as well as reducing the insertion of ionotropic and metabotropic receptors into the neuronal membrane. These actions increase the depolarization threshold of trigeminal and cervical nerve fibers, thus reducing their activation. The central actions of BT-A are still a matter of debate: a retrograde axonal transport has been postulated, but not clearly assessed in humans. Clinically, the efficacy of BT-A in CM has been assessed by large, randomized placebo-controlled trials, such as the Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) trials. Those results were also confirmed in a wide range of open-label studies, even for long-term periods. Recently, novel findings have led to a better understanding of its pharmacological actions and clinical usefulness in migraine prevention. This narrative review summarizes, updates and critically revises the available data on BT-A and its possible implementation in chronic migraine. Moreover, the current role of BT-A in CM treatment has been discussed.

Effectiveness of onabotulinumtoxinA (BOTOX®) for the preventive treatment of chronic migraine: A meta-analysis on 10 years of real-world data

BACKGROUND

This meta-analysis evaluated the real-world effectiveness of onabotulinumtoxinA (BOTOX®), the first preventive treatment FDA-approved specifically for chronic migraine in 2010.

METHODS

We systematically reviewed onabotulinumtoxinA observational data in chronic migraine published between 1 January 2010 and 31 March 2021. Random-effects models evaluated available data for primary and secondary endpoints defined in onabotulinumtoxinA pivotal trials at approximately 24 weeks and 52 weeks.

RESULTS

Of the 44 full-text eligible studies (29 prospective; 13 retrospective; 2 other), seven evaluated change from baseline (mean[confidence interval]) at ∼24 weeks and ∼52 weeks, respectively, for onabotulinumtoxinA in: number of headache days/month: (-10.64 [-12.31, -8.97]; -10.32 [-14.92, -5.73]); number of days of acute headache pain medication intake per month (-7.40 [-13.04, -1.77]; overlapping CIs at 52 weeks); total Headache Impact Test-6 score (-11.70 [-13.86, -9.54]); -11.80 [14.70, -8.90]); and Migraine-Specific Quality-of-Life v2.1 score (MSQ; 23.60 [CI: 21.56, 25.64]; 30.90 [CI: 28.29, 33.51]). At ∼24 weeks onabotulinumtoxinA showed total Migraine Disability Assessment score of 44.74 [28.50, 60.99] and ≥50% reduction in migraine days response rate of 46.57% [29.50%, 63.65%]. A sensitivity analysis at study-end suggested durability of onabotulinumtoxinA effectiveness on MSQ.

CONCLUSION

The meta-analysis reflecting real-world practice broadly corroborated with evidence from pivotal and long-term open-label studies of onabotulinumtoxinA in chronic migraine preventive treatment.

Response Predictors of Repetitive Neuromuscular Magnetic Stimulation in the Preventive Treatment of Episodic Migraine

Background

Repetitive neuromuscular magnetic stimulation (rNMS) of the trapezius muscles showed beneficial effects in preventing episodic migraine. However, clinical characteristics that predict a favorable response to rNMS are unknown. The objective of this analysis is to identify such predictors.

Methods

Thirty participants with a diagnosis of episodic migraine (mean age: 24.8 ± 4.0 years, 29 females), who were prospectively enrolled in two non-sham-controlled studies evaluating the effects of rNMS were analyzed. In these studies, the interventional stimulation of the bilateral trapezius muscles was applied in six sessions and distributed over two consecutive weeks. Baseline and follow-up assessments included the continuous documentation of a headache calendar over 30 days before and after the stimulation period, the Migraine Disability Assessment Score (MIDAS) questionnaire (before stimulation and 90 days after stimulation), and measurements of pain pressure thresholds (PPTs) above the trapezius muscles by algometry (before and after each stimulation session). Participants were classified as responders based on a ≥25% reduction in the variable of interest (headache frequency, headache intensity, days with analgesic intake, MIDAS score, left-sided PPTs, right-sided PPTs). Post-hoc univariate and multivariate binary logistic regression analyses were performed.

Results

Lower headache frequency (P = 0.016) and intensity at baseline (P = 0.015) and a migraine diagnosis without a concurrent tension-type headache component (P = 0.011) were significantly related to a ≥25% reduction in headache frequency. Higher headache frequency (P = 0.052) and intensity at baseline (P = 0.014) were significantly associated with a ≥25% reduction in monthly days with analgesic intake. Lower right-sided PPTs at baseline were significantly related to a ≥25% increase in right-sided PPTs (P = 0.0.015) and left-sided PPTs (P =0.030). Performance of rNMS with higher stimulation intensities was significantly associated with a ≥25% reduction in headache intensity (P = 0.046).

Conclusions

Clinical headache characteristics at baseline, the level of muscular hyperalgesia, and stimulation intensity may inform about how well an individual patient responds to rNMS. These factors may allow an early identification of patients that would most likely benefit from rNMS.

Does “wearing off” of efficacy occur in galcanezumab‐treated patients at the end of the monthly treatment cycle? Post hoc analyses of four phase III randomized trials

Objective

The purpose of this study was to propose a definition of “wearing off” at the individual patient‐level and determine the percentage of patients with migraine who experience “wearing off” of efficacy of galcanezumab at the end of a treatment cycle using this predefined threshold.

Background

Anecdotal reports suggest that some patients may experience “wearing off” of efficacy during the last week of their calcitonin gene‐related peptide monoclonal antibody treatment cycle. A previous post hoc analysis of galcanezumab demonstrated consistent efficacy at each week throughout all monthly dosing intervals at the population‐level, but “wearing off” has not been assessed at the individual patient‐level.

Methods

Post hoc analyses of clinical trial data from four galcanezumab phase III, randomized, placebo‐controlled studies in a total of 2680 patients with high‐frequency episodic migraine (EVOLVE‐1, EVOLVE‐2, and CONQUER studies) or chronic migraine (CM; REGAIN and CONQUER studies) were conducted. “Wearing off” was defined as an increase of greater than or equal to 2 weekly migraine headache days in the last week of the treatment cycle compared to the second week for at least 2 months. The analyses were conducted (1) in all patients and (2) in patients with a clinically meaningful response to treatment.

Results

The percentage of patients meeting the threshold of “wearing off” was not statistically significantly different among the placebo, galcanezumab 120 mg, and galcanezumab 240 mg treatment groups, both in the total population and in patients with a clinically meaningful response (all ≤9.0%). Although the frequency of “wearing off” in patients with CM and prior preventive failures was numerically greater in the galcanezumab groups (8/89 or 9.0%) compared to placebo (3/95 or 3.2%), these differences were not statistically significant.

Conclusions

Consistent with previous analyses at the population‐level that showed no evidence of decreased efficacy at the end of a treatment cycle, rates of individual patients meeting the threshold of “wearing off” in this analysis were low and similar among placebo, galcanezumab 120 mg, and galcanezumab 240 mg treatment groups.

Botulinum toxin type A wear-off phenomenon in chronic migraine patients: how long does the maximum efficiency last?

BACKGROUND

Botulinum toxin Type A (BoNTA) is a successful treatment for chronic migraine prophylaxis.

OBJECTIVE

We aimed to evaluate the monthly change of effectiveness of BoNTA treatment.

METHODS

A total of 80 patients (70 females and 10 males) with chronic migraine were included. In our study protocol, we applied to 155 U across 31 fixed-sites and if the patient had pain, 40 U dose injections were applied across 8 specific head/neck muscle areas. Headache days and analgesic intake were noted before the BoNTA injection and during the interviews at the first, second, and third months after the BoNTA injection.

RESULTS

The mean age was 37.59 ± 7.60 and 87.5% of the patients were female. The mean number of headache days/month before BoNTA was 18.95±2.69, decreasing to 10.55±3.15 days/month in the first month (p<0.001), 9.31±2.43 days/month in the second month (p<0.001), and increased to 11.97±3.27 days/month in the third month (p<0.001). The mean analgesic intake before BoNTA was 11.48±4.68 tablets/month, while it decreased to 6.53±2.72 tablets/month in the first month (p<0.001) and 5.40±2.46 tablets/month in the second month (p<0.001). In the third month, it was 5.85±2.59 tablets/month (p<0.001). There was a significant increase in pain medication use from the second to the third month (p<0.001).

CONCLUSION

In our study, there was a significant reduction in analgesic intake and headache days in the first and second months after BoNTA injection, and an increase was observed in the third month.

OnabotulinumtoxinA in Migraine: A Review of the Literature and Factors Associated with Efficacy

The efficacy of onabotulinumtoxinA (OnaB-A) as a preventative treatment for chronic migraine, emerging fortuitously from clinical observation is now supported by class one evidence and over two decades of real-world clinical data. There is still limited ability to predict a clinically meaningful response to OnaB-A for individual patients, however. This review summarises briefly the proposed mechanism of OnaB-A in chronic migraine, the literature of predictors of clinical response, and recent developments in the field.

No "Wearing-Off Effect" Seen in Quarterly or Monthly Dosing of Fremanezumab: Subanalysis of a Randomized Long-Term Study

OBJECTIVE

To evaluate whether quarterly or monthly administration of fremanezumab for migraine prevention exhibits a pattern of decreased efficacy toward the end of the dosing interval (wearing-off effect).

BACKGROUND

The main goals of migraine preventive treatment are to reduce the frequency, severity, and duration of migraine attacks, and migraine-associated disability. Wearing-off refers to the phenomenon whereby clinical symptoms return or worsen before the next dose of a drug is due and has been reported previously with migraine preventive medications.

DESIGN AND METHODS

This was a long-term, 12-month, multicenter, randomized, double-blind, parallel-group phase 3 study (NCT02638103) that included chronic (CM) and episodic migraine (EM) patients who rolled over from the 12-week phase 3 HALO CM (NCT02621931) and EM trials (NCT02629861), as well as an additional subset of 312 new patients. Patients with CM or EM received fremanezumab either monthly or quarterly. In this post hoc analysis, for selected months, the difference in the average number of migraine days between weeks 1-2 and weeks 3-4, between weeks 1-3 and week 4, and between weeks 1-2 and weeks 11-12 were calculated.

RESULTS

A total of 1890 patients (CM, 1110; EM, 780) were enrolled. At months 3, 6, 9, and 15, there were no substantial differences in mean weekly migraine days between weeks 1-2 and weeks 3-4 or between weeks 1-3 and week 4 with quarterly or monthly fremanezumab in the CM or EM subgroups. There were no substantial increases in mean weekly migraine days between weeks 1-2 and weeks 11-12 during the first quarter of treatment (months 1-3) or the second quarter of treatment (months 4-6) with quarterly or monthly fremanezumab in the CM or EM subgroups. Across both dosing subgroups in CM and EM patients, the mean weekly number of migraine days decreased substantially (30%-42%) during the first 2 weeks; decreases in weekly migraine days remained steady during the last 2 weeks of the first quarter, with a similar maintenance of response during the second quarter.

CONCLUSIONS

This analysis of data from a long-term, phase 3 study showed that patients receiving quarterly fremanezumab or monthly fremanezumab did not experience a wearing-off effect toward the end of the dosing interval.

Wear-Off of OnabotulinumtoxinA Effect Over the Treatment Interval in Chronic Migraine: A Retrospective Chart Review With Analysis of Headache Diaries

OBJECTIVE

To quantify wear-off of the response to OnabotulinumtoxinA (OnabotA) treatment over the treatment cycle in chronic migraine at group and individual level.

BACKGROUND

OnabotA administered quarterly is an effective treatment for chronic migraine. However, some patients report that headache recurs before the scheduled follow-up injection.

METHODS

In this retrospective chart review performed in 6 university outpatient centers or private practices specialized in headache treatment, 112 patients with a ≥30% response to OnabotA who completed headache diaries over 13 weeks after OnabotA treatment were included (age [mean ± SD] 45 ± 12 years, 82% female, headache days/month at baseline 24 ± 6).

RESULTS

Compared to weeks 5 to 8 after injection, headache days/week increased significantly in weeks 12 (+0.52 ± 1.96, 95% CI [0.15, 0.88], P < .009) and 13 (+1.15 ± 1.95, CI[0.79, 1.52], P < .001), demonstrating significant wear-off of the OnabotA effect. Similarly, acute medication days/week significantly increased in weeks 12 (0.38±1.67, CI [0.06, 0.69], P ≤ .027) and 13 (+0.83 ± 1.76, CI [0.49, 1.16], P < .001). At an individual level, 57 patients (51%) showed ≥30% wear-off by weeks 12 and 13, and 28 patients (25%) showed ≥30% wear-off already by weeks 10 and 11. Age, gender, OnabotA dose or cycle number, or headache center did not predict individual wear-off.

CONCLUSIONS

These data show that in clinical practice, on average the response of chronic migraine patients to OnabotA injection shows a clinically significant wear-off from week 12 after treatment. About 25% of the patients experience wear-off even by weeks 10 and 11. It must be noted that wear-off detected in a real-world study on OnabotA responders can be due to wear-off of a pharmacological OnabotA effect or a placebo effect, or to regression to the mean effects. This wear-off phenomenon may negatively affect quality of life of chronic migraine patients under OnabotA treatment. The best way to counteract wear-off remains to be determined.

OnabotulinumtoxinA injection in the treatment of chronic migraine

The earliest descriptions of botulism were in the early 19th century, and was reported by the German physician Justinus Kerner. The term "botulism" was derived from the Latin word botulus, indicating its original association with sausages. It took another 150 years or so to come into clinical use. The first clinical application was strabismus, and was developed by the American ophthalmologist Alan B. Scott, whose effort led to the pharmaceutical product known as onabotulinumtoxinA today. The therapeutic benefit in migraine was an incidental finding in a report by the American plastic surgeon William J. Binder, which inspired a series of clinical studies in headache disorders. The doses and injection techniques in the earlier reports were variable, so were the results. It was until the Phase III REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) 1 and 2 studies when its efficacy and safety, as well as the indication, i.e., chronic migraine (CM), were ascertained. Even though there were criticisms regarding the heterogeneities in the results between the PREEMPT 1 and 2 studies, the data on efficacy endpoints and safety were generally consistent, which were subsequently confirmed by the open-label extension of the PREEMPT 1 and 2 studies, and three open-label studies, namely the Chronic Migraine OnabotulinuMtoxinA Prolonged Efficacy open Label (COMPEL), the REal-life use of botulinum toxin for the symptomatic treatment of adults with chronic migraine, measuring healthcare resource utilization, and Patient-reported OutcomeS observed in practice (REPOSE) studies, and the CM Post-Authorization Safety Study (CM PASS) studies. On the other hand, the results were challenged by the Chronification and Reversibility of Migraine (CHARM) study, which involved CM patients with medication overuse. It was concluded that the clinical improvement was attributed to early withdrawal of the overused acute medications, rather than onabotulinumtoxinA injections. However, fundamental differences in the patient profile and methodology between the CHARM and PREEMPT studies existed, and cautious should be exercised when interpreting and comparing the results. According to the practical guidelines and reimbursement regulations in many countries, its use is limited to CM patients, and is reserved for those who fail at least 2-3 preventive medications, due to either lack of efficacy or intolerability. Cessation of treatment is recommended in patients who do not respond to 2-3 injection cycles, or in patients whose headache frequency has dropped to <10-15 days a month. Even in the era of calcitonin-gene-related peptide monoclonal antibodies, onabotulinumtoxinA injection remains a treatment option of reasonable cost-effectiveness in carefully selected patients.

OnabotulinumtoxinA in Chronic Migraine: A Profile of Its Use

OnabotulinumtoxinA (Botox^®; a formulation of botulinum toxin type A (BoNT/A)] is indicated for the prevention of headaches in adults with chronic migraine (CM) in numerous countries, including those of Europe. In clinical trials, intramuscular administration of BoNT/A (155-195 units at 12-week intervals) to patients with CM was generally well tolerated and associated with sustained and clinically meaningful improvements in multiple assessments of headache symptoms, headache-related impact and/or disability and migraine-specific health-related quality of life over a period of 1 year (in the pivotal PREEMPT 1 and 2 studies) and 2 years (in the phase IV COMPEL study). The efficacy and safety of BoNT/A therapy have been confirmed in a number of large, prospective, real-world studies conducted in Europe, including the 2-year REPOSE study. Intramuscular BoNT/A has also demonstrated greater clinical utility than the oral prophylactic medication topiramate in a clinical practice setting (FORWARD study).

OnabotulinumtoxinA Wear-off Phenomenon in the Treatment of Chronic Migraine

OBJECTIVE

To evaluate the frequency and features of onabotulinumtoxinA (onabotA) wear-off in chronic migraine (CM).

BACKGROUND

Clinical experience suggests that patients with CM frequently perceive onabotA treatment duration <12 weeks, but this phenomenon has not been well explored.

METHODS

This study was a retrospective chart review of patients (n = 143) with CM initiated on onabotA over a 2-year period. Wear-off was considered present with the phrase documented, a quantitative headache day increase, or increased use of abortive medications, bridging therapies or emergency department visits in the 6 weeks preceding the subsequent administration.

RESULTS

Wear-off was present in 90/143 patients (62.9%). Age, sex, medication overuse, psychiatric comorbidity, injector training level, and mean days between injections did not differ between the wear-off and no wear-off groups. Mean units injected per session in the wear-off group until first documented wear-off were significantly less vs no wear-off group (166.0 ± 13.1 vs 173.4 ± 10.3, P = .0005). Wear-off most commonly occurred 2-4 weeks before the next injection (43.3%) and after the very first injection (40.0%). Intramuscular ketorolac injections (33.3%) and peripheral nerve blocks (25.6%) were the most common bridge therapies used in the wear-off period.

CONCLUSIONS

Most patients with CM receiving onabotA experience wear-off. Clinicians may consider increasing the units used from the treatment onset to reduce the frequent need for bridging therapies.