Treatment of chronic migraine with Botox (onabotulinumtoxinA): Development, insights, and impact.

Chronic migraine (CM) is a neurological disease characterized by frequent migraine attacks that prevent affected individuals from performing daily activities of living, significantly diminish quality of life, and increase familial burden. Before onabotulinumtoxinA was approved for CM, there were few treatment options for these seriously disabled patients and none had regulatory approval. The terminology and recognition of CM evolved in parallel with the onabotulinumtoxinA clinical development program. Because there were no globally accepted classification criteria for CM when onabotulinumtoxinA was in development, the patient populations for the trials conducted by Allergan were determined by the Allergan migraine team in collaboration with headache scientists and clinicians. These trials and collaborations ultimately led to improvements in CM classifications. In 2010, onabotulinumtoxinA became the first medication and first biologic approved specifically to prevent headaches in patients with CM. Approval was based on 2 similarly designed phase 3, double-blind, randomized, placebo-controlled, multicenter clinical studies. Both studies showed significantly greater improvements in mean change from baseline in headache-day frequency in patients with CM receiving onabotulinumtoxinA compared with those receiving placebo. The safety and effectiveness of onabotulinumtoxinA have been established globally in >5000 patients with CM with or without medication overuse treated in clinical and observational studies. Benefits also include improvements in quality of life, fewer psychiatric comorbidities, and reduced healthcare resource utilization. Across studies, onabotulinumtoxinA was well tolerated; adverse events tended to be mild or moderate in severity and to decline over subsequent treatment cycles.

Treatment of adult spasticity with Botox (onabotulinumtoxinA): Development, insights, and impact.

Upper and lower limb spasticity (ULS, LLS) often occur following a stroke or in patients with other neurological disorders, leading to difficulties in mobility and daily living and decreased quality of life. Prior to the use of onabotulinumtoxinA, antispastic medications had limited efficacy and often caused sedation. Phenol injections were difficult for physicians to perform, painful, and led to tissue destruction. The success of onabotulinumtoxinA in treating cervical dystonia led to its use in spasticity. However, many challenges characterized the development of onabotulinumtoxinA for adult spasticity. The wide variability in the presentation of spasticity among patients rendered it difficult to determine which muscles to inject and how to measure improvement. Another challenge was the initial refusal of the Food and Drug Administration to accept the Ashworth Scale as a primary endpoint. Additional scales were designed to incorporate a goal-oriented, patient-centered approach that also accounted for the variability of spasticity presentations. Several randomized, double-blind, placebo-controlled trials of post-stroke spasticity of the elbow, wrist, and/or fingers showed significantly greater improvements in the modified Ashworth Scale and patient treatment goals and led to the approval of onabotulinumtoxinA for the treatment of ULS in adult patients. Lessons learned from the successful ULS trials were applied to design an LLS trial that led to approval for the latter indication. Additional observational trials mimicking real-world treatment have shown continued effectiveness and patient satisfaction. The use of onabotulinumtoxinA for spasticity has ushered in a more patient-centered treatment approach that has vastly improved patients' quality of life.

Assessing clinically meaningful treatment effects in controlled trials: chronic migraine as an example.

UNLABELLED: In addition to headache, persons with chronic migraine (CM) experience multiple symptoms, both ictal and interictal, that may contribute to their suffering. Translating clinical trial results into practice requires assessment of the results' clinical meaningfulness. When examining treatment benefit in this disabled patient population, multiple headache-symptom measures should be considered to fully reflect clinical relevance. Currently, only onabotulinumtoxinA is approved specifically for headache prophylaxis in adults with CM. Topiramate is the only other therapeutic agent with double-blind, placebo-controlled evidence in this population. Herein we evaluate the clinical meaningfulness of onabotulinumtoxinA and topiramate as headache prophylaxis in CM by comparing primary endpoints from the placebo-controlled, double-blind phase of the Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) clinical program and the topiramate clinical trial (frequency of headache days [primary endpoint in PREEMPT; secondary in topiramate trial] and migraine/migrainous days [primary in topiramate trial, or "migraine/probable-migraine days"; secondary in PREEMPT]). Additionally, outcome measures such as responder rates, health-related quality of life, discontinuation rates, safety, and tolerability profiles are important clinical considerations. The clinical data indicate that statistically significant, clinically relevant treatment benefits exist for both onabotulinumtoxinA and topiramate. These data support these treatments as meaningful headache prophylaxis in adults with CM. PERSPECTIVE: CM is a chronic pain condition. We sought to determine the clinical relevance of recent trials in this disabled population. Clinical data indicate that statistically significant, clinically relevant treatment benefits exist for both onabotulinumtoxinA and topiramate, and support use of these treatments as meaningful headache prophylaxis in CM.

Per cent of patients with chronic migraine who responded per onabotulinumtoxinA treatment cycle: PREEMPT.

OBJECTIVE: The approved use of onabotulinumtoxinA for prophylaxis of headaches in patients with chronic migraine (CM) involves treatment every 12 weeks. It is currently unknown whether patients who fail to respond to the first onabotulinumtoxinA treatment cycle will respond to subsequent treatment cycles. To help inform decisions about treating non-responders, we examined the probability of treatment cycle 1 non-responders responding in cycle 2, and cycle 1 and 2 non-responders responding in cycle 3. METHODS: Pooled PREEMPT data (two studies: a 24-week, 2-cycle, double-blind, randomised (1:1), placebo-controlled, parallel-group phase, followed by a 32-week, 3-cycle, open-label phase) evaluated onabotulinumtoxinA (155-195 U) for prophylaxis of headaches in persons with CM (≥15 days/month with headache ≥4 h/day). End points of interest included the proportion of study patients who first achieved a ≥50% reduction in headache days, moderate/severe headache days, total cumulative hours of headache on headache days, or a ≥5-point improvement in Headache Impact Test (HIT)-6. For treatment cycle 1, all eligible participants were included. For subsequent cycles, responders in a previous cycle were no longer considered first responders. RESULTS: Among onabotulinumtoxinA-treated patients (n=688) 49.3% had a ≥50% reduction in headache-day frequency during treatment cycle 1, with 11.3% and 10.3% of patients first responding during cycles 2 and 3, respectively. 54.2%, 11.6% and 7.4% of patients first responded with a ≥50% reduction in cumulative hours of headache, and 56.3%, 14.5% and 7.7% of patients first responded with a ≥5-point improvement in total HIT-6 during treatment cycles 1, 2 and 3, respectively. CONCLUSIONS: A meaningful proportion of patients with CM treated with onabotulinumtoxinA who did not respond to the first treatment cycle responded in the second and third cycles of treatment. TRIAL REGISTRATION NUMBER: NCT00156910, NCT00168428.

Development of onabotulinumtoxinA for chronic migraine.

Discovery of the neuromuscular effects of botulinum toxin began in the early 19th century and has continued to evolve. Currently, onabotulinumtoxinA is approved by the U.S. Food and Drug Administration for two cosmetic and eight medical indications, including chronic migraine (CM). CM is a disabling form of migraine characterized by ≥15 headache days monthly and is believed to result from neuronal hypersensitivity to proinflammatory mediators, upregulation of sensory receptors, and consequent maladaptive pain responses with peripheral and central sensitization. OnabotulinumtoxinA achieves migraine prophylaxis in CM through regulation of vesicular trafficking and exocytosis, inhibition of peripheral release of neuropeptides and inflammatory peptides, and reduced cell surface expression of certain ion channels and receptors. Clinically, efficacy of onabotulinumtoxinA for CM has been shown in two phase III, placebo-controlled trials (PREEMPT 1 and PREEMPT 2). OnabotulinumtoxinA significantly reduced the number of headache days per 28-day cycle relative to placebo at week 24 (change from baseline: -8.4 days for onabotulinumtoxinA versus -6.6 days for placebo; P < 0.001, pooled data). OnabotulinumtoxinA improved health-related quality of life and had an acceptable safety profile. OnabotulinumtoxinA is the only approved treatment specifically for CM prevention and represents a safe and effective therapeutic for chronic migraineurs.

Improving the classification of migraine subtypes: an empirical approach based on factor mixture models in the American Migraine Prevalence and Prevention (AMPP) Study.

OBJECTIVES: Refine the classification of migraine subtypes by applying factor mixture models (FMM) to a large population sample of people with headache. BACKGROUND: Current classification of primary headache disorders is symptom-based and uses somewhat arbitrary boundaries developed by expert consensus. Symptom profiles and headache frequency are used to distinguish among probable migraine (PM), episodic migraine (EM), high-frequency episodic migraine (HFEM), and chronic migraine (CM). Herein, we used statistical approaches to parse the heterogeneity in the broad group of persons with migraine and test the hypothesis that the groups that emerge differ in prognosis. METHODS: The American Migraine Prevalence and Prevention study mailed surveys to a sample of 120,000 US households selected to represent the US population in 2004. Follow-up surveys were sent to a random sample of 24,000 respondents with "severe headache" on an annual basis from 2005 to 2009. People meeting International Classification of Headache Disorders, Second Edition, criteria for migraine were classified as EM (<15 headache days/month) and CM (≥15 headache days/month) based on modified Silberstein-Lipton criteria. The EM group was subdivided into HFEM (10 to 14 headache days/month) and low-frequency episodic migraine (LFEM; <10 headache days/month). Factor mixture models (FMM) identified 5 subgroups of migraine (taxa) using data from the 2005 survey on the severity of migraine symptoms, average migraine pain intensity, headache-related disability, cutaneous allodynia and depression, as well as monthly headache and migraine frequency as determinants of class membership. We assessed the validity of these taxa by examining the distribution of clinical diagnoses at cross-section and the rate of CM onset within these groups. RESULTS: Data from the 2005 American Migraine Prevalence and Prevention survey were used for the FMM and data from the 2006-2009 surveys were used to assess prognosis of groups defined based on FMM. In total, 12,860 participants were eligible for classification analysis, including 10,162 with LFEM and 601 with HFEM, 1302 with probable migraine, and 795 with CM. Of these, 3152 (24.5%), 1076 (8.4%), 3896 (30.3%), 2251 (17.5%), and 2485 (19.3%) were assigned to Taxons 1, 2, 3, 4, and 5, respectively. Overall, there was a strong association between taxon assignment and clinical diagnosis. As the most prevalent disorder in the sample, EM was the largest contributor to each of the 5 taxa, constituting more than 80% of each group other than Taxon 2. Taxon 2 was enriched with the most severe spectrum of migraine including the highest concentrations of CM (28.4%) and HFEM (22.6%), whereas Taxon 5 represented the least severe end of the migraine spectrum including the lowest concentrations of CM (0%) and HFEM (0.08%). Validity of taxon assignment was tested by the ability of taxon membership to predict clinical course. For Taxon 2, 22% of those free of CM at baseline developed it. For Taxon 5, less than 2% of CM-free Taxon 5 members developed it. CONCLUSION: Statistically based classification using FMM extends traditional clinical syndrome-based diagnosis. FMM can serve as an important tool to parse phenotypic heterogeneity and identify natural migraine subgroups. This approach may improve our ability to diagnosis migraine, to select initial therapy, to predict prognosis, and to discover biomarkers and genes.

OnabotulinumtoxinA for treatment of chronic migraine: PREEMPT 24-week pooled subgroup analysis of patients who had acute headache medication overuse at baseline.

Acute headache medication overuse (MO) is common in patients with chronic migraine (CM). We evaluated safety and efficacy of onabotulinumtoxinA as preventive treatment of headache in CM patients with baseline MO (CM+MO) in a planned secondary analysis from two similarly designed, randomized, placebo-controlled, parallel, Phase III trials. Patients were randomized to treatment groups (155-195 U of onabotulinumtoxinA or placebo) using MO (patient-reported and diary-captured frequency of intake) as a stratifying variable. Of 1384 patients, 65.3% (n=904) met MO criteria (onabotulinumtoxinA: n=445, placebo: n=459). For the CM+MO subgroup at Week 24, statistically significant between-treatment group mean changes from baseline favoring onabotulinumtoxinA versus placebo were observed for headache days (primary endpoint: -8.2 vs. -6.2; p<0.001) and other secondary endpoints: frequencies of migraine days (p<0.001), moderate/severe headache days (p<0.001), cumulative headache hours on headache days (p<0.001), headache episodes (p=0.028), and migraine episodes (p=0.018) and the percentage of patients with severe Headache Impact Test-6 category (p<0.001). At Week 24, change from baseline in frequency of acute headache medication intakes (secondary endpoint) was not statistically significant (p=0.210) between groups, except for triptan intakes (p<0.001), where the onabotulinumtoxinA-treated group was favored. OnabotulinumtoxinA was effective and well tolerated as headache prophylaxis in CM+MO patients.

Depression and risk of transformation of episodic to chronic migraine.

The aim of this study was to assess the role of depression as a predictor of new onset of chronic migraine (CM) among persons with episodic migraine (EM). The American Migraine Prevalence and Prevention (AMPP) study followed 24,000 persons with severe headache identified in 2004. Using random-effects logistic regression, we modeled the probability that persons with EM in 2005 or 2006 would develop CM in the subsequent year. Depression was assessed in two ways, using a validated questionnaire (PHQ-9 score ≥15) and based on self-reported medical diagnosis. Analyses were adjusted for multiple covariates including sociodemographics, body mass index, headache pain intensity, headache frequency, migraine symptom severity, cutaneous allodynia, acute medication overuse, anti-depressant use and anxiety. Of 6,657 participants with EM in 2005, 160 (2.4 %) developed CM in 2006. Of 6,852 participants with EM in 2006, 144 (2.2 %) developed CM in 2007. In fully adjusted models, PHQ-9 defined depression was a significant predictor of CM onset [odds ratio (OR) = 1.65, 95 % CI 1.12-2.45]. There was a depression-dose effect; relative to participants with no depression or mild depression, those with moderate (OR = 1.77, 95 % CI 1.25-2.52), moderately severe (OR = 2.35, 95 % CI 1.53-3.62), and severe depression (OR = 2.53, 95 % CI 1.52-4.21) were at increased risk for the onset of CM. Among persons with EM, depression was associated with an increased risk of CM after adjusting for sociodemographic variables and headache characteristics. Depression preceded the onset of CM and risk increased with depression severity suggesting a potentially causal role though reverse causality cannot be excluded.

Chronic migraine prevalence, disability, and sociodemographic factors: results from the American Migraine Prevalence and Prevention Study.

OBJECTIVES: To estimate the prevalence and distribution of chronic migraine (CM) in the US population and compare the age- and sex-specific profiles of headache-related disability in persons with CM and episodic migraine. BACKGROUND: Global estimates of CM prevalence using various definitions typically range from 1.4% to 2.2%, but the influence of sociodemographic factors has not been completely characterized. METHODS: The American Migraine Prevalence and Prevention Study mailed surveys to a sample of 120,000 US households selected to represent the US population. Data on headache frequency, symptoms, sociodemographics, and headache-related disability (using the Migraine Disability Assessment Scale) were obtained. Modified Silberstein-Lipton criteria were used to classify CM (meeting International Classification of Headache Disorders, second edition, criteria for migraine with a headache frequency of ≥15 days over the preceding 3 months). RESULTS: Surveys were returned by 162,756 individuals aged ≥12 years; 19,189 individuals (11.79%) met International Classification of Headache Disorders, second edition, criteria for migraine (17.27% of females; 5.72% of males), and 0.91% met criteria for CM (1.29% of females; 0.48% of males). Relative to 12 to 17 year olds, the age- and sex-specific prevalence for CM peaked in the 40s at 1.89% (prevalence ratio 4.57; 95% confidence interval 3.13-6.67) for females and 0.79% (prevalence ratio 3.35; 95% confidence interval 1.99-5.63) for males. In univariate and adjusted models, CM prevalence was inversely related to annual household income. Lower income groups had higher rates of CM. Individuals with CM had greater headache-related disability than those with episodic migraine and were more likely to be in the highest Migraine Disability Assessment Scale grade (37.96% vs. 9.50%, respectively). Headache-related disability was highest among females with CM compared with males. CM represented 7.68% of migraine cases overall, and the proportion generally increased with age. CONCLUSIONS: In the US population, the prevalence of CM was nearly 1%. In adjusted models, CM prevalence was highest among females, in mid-life, and in households with the lowest annual income. Severe headache-related disability was more common among persons with CM and most common among females with CM.

Relationship between disability and health-related quality of life and caregiver burden in patients with upper limb poststroke spasticity.

OBJECTIVE: To evaluate the relationship between disability and both health-related quality of life (HRQoL) and caregiver burden in patients with upper limb poststroke spasticity. DESIGN: Multicenter open-label study. SETTING: Thirty-five sites in North America. PARTICIPANTS: Patients (N = 279) with upper limb poststroke spasticity. METHODS: Post hoc analyses of data from an open-label study were performed to estimate HRQoL and caregiver burden at study baseline across levels of disability in 4 problem domains: hygiene, dressing, limb posture, and pain. Disability severity in these areas was determined by using the 4-point Disability Assessment Scale rated by the physicians. MAIN OUTCOME MEASUREMENTS: HRQoL measured by the patient-reported EuroQol 5 Dimensions questionnaire and the Stroke-Adapted Sickness Impact Profile and caregiver burden. RESULTS: At study baseline, increasing disability in the hygiene, dressing, and pain domains of the Disability Assessment Scale was associated with diminishing HRQoL scores (P < .002) measured by the EuroQol 5 Dimensions. By using the Stroke-Adapted Sickness Impact Profile, greater disability scores in all problem domains were significantly associated with higher overall dysfunction scores (P ≤ .05). Within the physical dimension of the Stroke-Adapted Sickness Impact Profile, significant associations also were observed in all domains. At baseline, caregiver burden was significantly related to increasing levels of hygiene and dressing domain severity (P ≤ .05). Caregiver assistance requirement increased from approximately 9.0-28.2 hours per week in the hygiene domain and 3.3-32.1 hours per week in the dressing domain as disability increased from "none" to "severe." CONCLUSIONS: In patients with upper limb poststroke spasticity, increasing disability in the hygiene, dressing, and pain domains of the Disability Assessment Scale were associated with diminishing HRQoL. Furthermore, these patients required caregiver assistance proportionally related to the severity of their disability in the hygiene and dressing domains.

OnabotulinumtoxinA for treatment of chronic migraine: pooled analyses of the 56-week PREEMPT clinical program.

OBJECTIVE: To evaluate safety and efficacy of onabotulinumtoxinA (BOTOX(®) ) as headache prophylaxis in adults with chronic migraine. BACKGROUND: Chronic migraine is a prevalent, disabling, and undertreated neurological disorder. OnabotulinumtoxinA is the only approved prophylactic therapy in this highly disabled patient population. DESIGN AND METHODS: Two phase III, 24-week, double-blind, parallel-group, placebo-controlled studies, followed by a 32-week, open-label, single-treatment, onabotulinumtoxinA phase, were conducted (January 23, 2006 to August 11, 2008). Qualified subjects were randomized (1:1) to injections of onabotulinumtoxinA (155-195 U) or placebo every 12 weeks for 5 cycles (double-blind: 2, open-label: 3). The pooled primary variable was mean change from baseline in frequency of headache days. Secondary variables included proportion of patients with severe Headache Impact Test-6 score (≥ 60) and mean changes from baseline in frequencies of migraine days, moderate/severe headache days, and migraine episodes; cumulative hours of headache on headache days; and acute headache medication intakes. The primary time point was week 24. Assessments for the open-label phase (all patients treated with onabotulinumtoxinA) compared double-blind treatment groups (onabotulinumtoxinA/onabotulinumtoxinA vs placebo/onabotulinumtoxinA) and are summarized to give a descriptive view of consistent study results, with inferences regarding statistical significance only examined for week 56. RESULTS: A total of 1384 patients were randomized to onabotulinumtoxinA (n = 688) or placebo (n = 696) in the double-blind phase; 607 (88.2%) onabotulinumtoxinA/onabotulinumtoxinA and 629 (90.4%) placebo/onabotulinumtoxinA patients continued into the open-label phase. OnabotulinumtoxinA/onabotulinumtoxinA treatment statistically significantly reduced headache-day frequency vs placebo/onabotulinumtoxinA in patients with chronic migraine at week 56 (-11.7 onabotulinumtoxinA/onabotulinumtoxinA, -10.8 placebo/onabotulinumtoxinA; P = .019). Statistically significant reductions also favored onabotulinumtoxinA/onabotulinumtoxinA for several secondary efficacy variables at week 56, including frequencies of migraine days (-11.2 onabotulinumtoxinA/onabotulinumtoxinA, -10.3 placebo/onabotulinumtoxinA; P = .018) and moderate/severe headache days (-10.7 onabotulinumtoxinA/onabotulinumtoxinA, -9.9 placebo/onabotulinumtoxinA; P = .027) and cumulative headache hours on headache days (-169.1 onabotulinumtoxinA/onabotulinumtoxinA, -145.7 placebo/onabotulinumtoxinA; P = .018). After the open-label phase (all treated with onabotulinumtoxinA), statistically significant within-group changes from baseline were observed for all efficacy variables. Most patients (72.6%) completed the open-label phase; few discontinued because of adverse events. No new safety or tolerability issues emerged. CONCLUSIONS: Repeated treatment with ≤ 5 cycles of onabotulinumtoxinA was effective, safe, and well tolerated in adults with chronic migraine.

Prevalence and burden of chronic migraine in adolescents: results of the chronic daily headache in adolescents study (C-dAS).

OBJECTIVE: To estimate the prevalence of chronic migraine (CM) among adolescents and to describe the epidemiologic profile, headache characteristics, disability, and healthcare utilization of adolescents with CM in the USA. BACKGROUND: Chronic daily headache (CDH) and CM occur in children and adolescents, but are poorly understood in these populations because their presentation is different from that in adults. It may be difficult to assign a definitive diagnosis to young people suffering from CDH because symptoms may fail to meet the criteria for one of the CDH subtypes. METHODS: A large sample of households with at least one resident aged 12 to 19 years was selected in balance with the US Census. Data were collected in 3 phases: (1) mailed questionnaire; (2) telephone interview; and (3) 30-day interactive voice response system diary. CM prevalence was estimated by adapting the second edition of the International Classification of Headache Disorders criteria for CM to include pediatric migraine diagnostic criteria. The population was stratified for medication overuse. Medication overuse was defined as 15 or more days per month of acute medication use. Included in the study were measures of headache characteristics, headache impact (Headache Impact Test), disability (Pediatric Migraine Disability Assessment), and healthcare and medication use. Data are reported on subjects 12 to 17 years of age only. RESULTS: The US adolescent (12-17 years) prevalence rate for CM was 0.79% (0.00-1.70) excluding those with medication overuse and 1.75% (0.62-2.89) when adolescents with medication overuse were included. The majority of adolescents with CM had Headache Impact Test scores greater than or equal to 60, indicating severe headache impact, and mean Pediatric Migraine Disability Assessment scores greater than 17, indicating severe headache and disability. The majority of adolescents with CM (approximately 60%) had not visited a healthcare provider in the previous year and less than one in 5 reported taking medications to prevent headaches during the last month. CONCLUSIONS: Results suggest that CM occurs less frequently in adolescents than adults, but like adults, adolescents are severely burdened by the disorder. Data support an unmet medical need; however, the development of optimal criteria for diagnosing adolescents with CM is critical to fully understanding how medical needs can be met within this complex population.

Method of injection of onabotulinumtoxinA for chronic migraine: a safe, well-tolerated, and effective treatment paradigm based on the PREEMPT clinical program.

Chronic migraine (CM) is a prevalent and disabling neurological disorder. Few prophylactic treatments for CM have been investigated. OnabotulinumtoxinA, which inhibits the release of nociceptive mediators, such as glutamate, substance P, and calcitonin gene-related peptide, has been evaluated in randomized, placebo-controlled studies for the preventive treatment of a variety of headache disorders, including CM. These studies have yielded insight into appropriate patient selection, injection sites, dosages, and technique. Initial approaches used a set of fixed sites for the pericranial injections. However, the treatment approach evolved to include other sites that corresponded to the location of pain and tenderness in the individual patient in addition to the fixed sites. The Phase III REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) injection paradigm uses both fixed and follow-the-pain sites, with additional specific follow-the-pain sites considered depending on individual symptoms. The PREEMPT paradigm for injecting onabotulinumtoxinA has been shown to be safe, well-tolerated, and effective in well-designed, controlled clinical trials and is the evidence-based approach recommended to optimize clinical outcomes for patients with CM.

OnabotulinumtoxinA for treatment of chronic migraine: pooled results from the double-blind, randomized, placebo-controlled phases of the PREEMPT clinical program.

OBJECTIVE: To assess the efficacy, safety, and tolerability of onabotulinumtoxinA (BOTOX) as headache prophylaxis in adults with chronic migraine. BACKGROUND: Chronic migraine is a prevalent, disabling, and undertreated neurological disorder. Few preventive treatments have been investigated and none is specifically indicated for chronic migraine. METHODS: The 2 multicenter, pivotal trials in the PREEMPT: Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy clinical program each included a 24-week randomized, double-blind phase followed by a 32-week open-label phase (ClinicalTrials.gov identifiers NCT00156910, NCT00168428). Qualified patients were randomized (1:1) to onabotulinumtoxinA (155-195 U) or placebo injections every 12 weeks. Study visits occurred every 4 weeks. These studies were identical in design (eg, inclusion/exclusion criteria, randomization, visits, double-blind phase, open-label phase, safety assessments, treatment), with the only exception being the designation of the primary and secondary endpoints. Therefore, the predefined pooling of the results was justified and performed to provide a complete overview of between-group differences in efficacy, safety, and tolerability that may not have been evident in individual studies. The primary endpoint for the pooled analysis was mean change from baseline in frequency of headache days at 24 weeks. Secondary endpoints were mean change from baseline to week 24 in frequency of migraine/probable migraine days, frequency of moderate/severe headache days, total cumulative hours of headache on headache days, frequency of headache episodes, frequency of migraine/probable migraine episodes, frequency of acute headache pain medication intakes, and the proportion of patients with severe (> or =60) Headache Impact Test-6 score at week 24. Results of the pooled analyses of the 2 PREEMPT double-blind phases are presented. RESULTS: A total of 1384 adults were randomized to onabotulinumtoxinA (n = 688) or placebo (n = 696). Pooled analyses demonstrated a large mean decrease from baseline in frequency of headache days, with statistically significant between-group differences favoring onabotulinumtoxinA over placebo at week 24 (-8.4 vs -6.6; P < .001) and at all other time points. Significant differences favoring onabotulinumtoxinA were also observed for all secondary efficacy variables at all time points, with the exception of frequency of acute headache pain medication intakes. Adverse events occurred in 62.4% of onabotulinumtoxinA patients and 51.7% of placebo patients. Most patients reported adverse events that were mild to moderate in severity and few discontinued (onabotulinumtoxinA, 3.8%; placebo, 1.2%) due to adverse events. No unexpected treatment-related adverse events were identified. CONCLUSIONS: The pooled PREEMPT results demonstrate that onabotulinumtoxinA is an effective prophylactic treatment for chronic migraine. OnabotulinumtoxinA resulted in significant improvements compared with placebo in multiple headache symptom measures, and significantly reduced headache-related disability and improved functioning, vitality, and overall health-related quality of life. Repeat treatments with onabotulinumtoxinA were safe and well tolerated.

Formation of neutralizing antibodies in patients receiving botulinum toxin type A for treatment of poststroke spasticity: a pooled-data analysis of three clinical trials.

OBJECTIVE: The purpose of this study was to investigate the incidence of neutralizing antibody (NAb) formation in patients with poststroke spasticity treated with a specific formulation of botulinum toxin type A (BoNTA). METHODS: Data from 3 previous clinical trials of BoNTA in patients with upper and/or lower limb spasticity were pooled and evaluated. Study 1 was a randomized, double-blind, placebo-controlled, multicenter trial of BoNTA in patients aged >/=21 years who had experienced a stroke >6 months before the initiation of the study. Study 2 was an open-label extension of study 1. Study 3 was a randomized, double-blind, multicenter trial of a specific BoNTA formulation in patients aged >/= 21 years who had experienced a stroke >/=6 weeks before study entry. Patients with a fixed contracture of the studied limb were excluded from participation in studies 1 and 2. Serum samples were obtained from each patient before each BoNTA treatment and at the end of each study. The mouse protection assay (MPA) was used for detection of NAbs to BoNTA in serum. RESULTS: A total of 235 individual patients with post-stroke spasticity were enrolled in the 3 trials, including 126, 111 (all of whom participated in study 1), and 109 in studies 1, 2, and 3, respectively. Study 1 had an equal (50.0%) distribution of male and female patients (63/63). The distribution of male and female patients was 56 (50.5%) and 55 (49.5%), respectively, in study 2, and 55 (50.5%) and 54 (49.5), respectively, in study 3. The mean (SD) ages of patients in studies 1, 2, and 3 were 61.4 (13.8), 61.5 (14.1), and 58.5 (13.9) years, respectively. The MPA was used for detection of NAbs to BoNTA in the serum samples of 191 patients, including 64 from study 1, 111 from study 2 (55 of these patients were placebo recipients and 56 received their first BoNTA injection in study 1), and 72 (a sample was not obtained for 1 patient who had not received an injection) from study 3. The median number of BoNTA treatments received by these patients was 2 (range, 1-4 treatments) over a period lasting from 12 to 42 weeks. The mean dose of BoNTA was 241 U (range, 100-400 U), with a maximum dose of 960 U in any 1 patient. NAbs to BoNTA were detected in the serum sample of 1/191 (0.5%) patient who had participated in studies 1 and 2. Based on muscle-tone scores (3 and 4 for wrist and fingers, respectively) on a 5-point Ashworth Scale (0 = none to 4 = severe), the patient did not appear to exhibit a clinical response to BoNTA at any time during the studies. CONCLUSION: Formation of NAbs was rare (1/191) in this group of adults with poststroke spasticity from three 12- to 42-week clinical trials who received >/=1 treatment with a specific BoNTA formulation at doses ranging from 100 to 400 U.

Pooled analysis of the safety of botulinum toxin type A in the treatment of poststroke spasticity.

OBJECTIVE: To examine the safety of botulinum toxin type A (BTX-A). DESIGN: Analysis of pooled data of 9 double-blind, placebo-controlled studies of patients with spasticity after stroke. SETTING: University hospitals and specialty rehabilitation centers in the United States. PARTICIPANTS: A total of 482 patients with upper-limb spasticity and 310 with lower-limb spasticity (overall mean age, 58y; 60% men). INTERVENTION: Treatment with BTX-A (n=534; 1-3 treatments; mean dose, 231U) or placebo (n=258). MAIN OUTCOME MEASURE: Adverse events. RESULTS: Most patients (69%) received only 1 treatment with BTX-A. Patients were followed for a mean of 17.8 weeks (range, 0.1-44.7wk) after each treatment. A total of 352 (65.9%) patients in the BTX-A group and 163 (63.2%) in the placebo group reported at least 1 adverse event (P=.475). The most frequent adverse events reported by patients (>5% but <10% in either group) were respiratory infection, seizures, incoordination, and injection site pain, none of which occurred at a significantly higher rate in the BTX-A group (all P>.05). The majority of adverse events were rated as mild or moderate in severity. Only nausea was reported at a significantly higher rate in the BTX-A group (12/534 [2.2%]) than the placebo group (0/258) (P=.011); in contrast, injection site pain, chest pain, and allergic reaction were reported significantly more frequently in the placebo group. CONCLUSIONS: BTX-A has an acceptable safety profile for treatment of patients with focal spasticity following stroke, a population in which adverse events and comorbidities are common.

Botulinum toxin type A for the prophylactic treatment of chronic daily headache: a randomized, double-blind, placebo-controlled trial.

OBJECTIVES: To identify a treatment-responsive population for botulinum toxin type A (BoNTA) and to evaluate the safety and efficacy of 3 different doses of BoNTA as prophylactic treatment of chronic daily headache (CDH). PATIENTS AND METHODS: A randomized, double-blind, placebo-controlled study of BoNTA in patients with CDH was conducted from July 6, 2001, through November 7, 2003, at 28 North American study centers. Eligible patients were injected with BoNTA at 225 U, 150 U, 75 U, or placebo and returned for additional masked treatments at day 90 and day 180. Patients were assessed every 30 days for 9 months. The primary efficacy end point was the mean change from baseline in the frequency of headache-free days at day 180 for the placebo nonresponder group. RESULTS: For this study, 702 patients were enrolled and randomized. The primary efficacy end point was not met. Mean improvements from baseline at day 180 of 6.0, 7.9, 7.9, and 8.0 headache-free days per month were observed in the placebo nonresponder group treated with BoNTA at 225 U, 150 U, 75 U, or placebo, respectively (P=.44). An a priori-defined analysis of headache frequency revealed that BoNTA at 225 U or 150 U had significantly greater least squares mean changes from baseline than placebo at day 240 (-8.4, -8.6, and -6.4, respectively; P=.03 analysis of covariance). Only 27 of 702 patients (3.8%) withdrew from the study because of adverse events, which generally were transient and mild to moderate. CONCLUSIONS: Although the primary efficacy end point was not met, all groups responded to treatment. The 225 U and 150 U groups experienced a greater decrease in headache frequency than the placebo group at day 240. The placebo response was higher than expected. BoNTA was safe and well tolerated. Further study of BoNTA prophylactic treatment of CDH appears warranted.