Clinical comparisons of botulinum neurotoxin formulations

Aminopyridines Restore Ventilation and Reverse Respiratory Acidosis at Late Stages of Botulism in Mice

Botulinum neurotoxin (BoNT) is a potent protein toxin that causes muscle paralysis and death by asphyxiation. Treatments for symptomatic botulism are intubation and supportive care until respiratory function recovers. Aminopyridines have recently emerged as potential treatments for botulism. The clinically approved drug 3,4-diaminopyridine (3,4-DAP) rapidly reverses toxic signs of botulism and has antidotal effects when continuously administered in rodent models of lethal botulism. Although the therapeutic effects of 3,4-DAP likely result from the reversal of diaphragm paralysis, the corresponding effects on respiratory physiology are not understood. Here, we combined unrestrained whole-body plethysmography (UWBP) with arterial blood gas measurements to study the effects of 3,4-DAP, and other aminopyridines, on ventilation and respiration at terminal stages of botulism in mice. Treatment with clinically relevant doses of 3,4-DAP restored ventilation in a dose-dependent manner, producing significant improvements in ventilatory parameters within 10 minutes. Concomitant with improved ventilation, 3,4-DAP treatment reversed botulism-induced respiratory acidosis, restoring blood levels of CO2, pH, and lactate to normal physiologic levels. Having established that 3,4-DAP-mediated improvements in ventilation were directly correlated with improved respiration, we used UWBP to quantitatively evaluate nine additional aminopyridines in BoNT/A-intoxicated mice. Multiple aminopyridines were identified with comparable or enhanced therapeutic efficacies compared with 3,4-DAP, including aminopyridines that selectively improved tidal volume versus respiratory rate and vice versa. In addition to contributing to a growing body of evidence supporting the use of aminopyridines to treat clinical botulism, these data lay the groundwork for the development of aminopyridine derivatives with improved pharmacological properties. SIGNIFICANCE STATEMENT: There is a critical need for fast-acting treatments to reverse respiratory paralysis in patients with botulism. This study used unrestrained, whole-body plethysmography and arterial blood gas analysis to show that aminopyridines rapidly restore ventilation and respiration and reverse respiratory acidosis when administered to mice at terminal stages of botulism. In addition to supporting the use of aminopyridines as first-line treatments for botulism symptoms, these data are expected to contribute to the development of new aminopyridine derivatives with improved pharmacological properties.

Neuromuscular recovery from botulism involves multiple forms of compensatory plasticity

Introduction

Botulinum neurotoxin (BoNT) causes neuroparalytic disease and death by blocking neuromuscular transmission. There are no specific therapies for clinical botulism and the only treatment option is supportive care until neuromuscular function spontaneously recovers, which can take weeks or months after exposure. The highly specialized neuromuscular junction (NMJ) between phrenic motor neurons and diaphragm muscle fibers is the main clinical target of BoNT. Due to the difficulty in eliciting respiratory paralysis without a high mortality rate, few studies have characterized the neurophysiological mechanisms involved in diaphragm recovery from intoxication. Here, we develop a mouse model of botulism that involves partial paralysis of respiratory muscles with low mortality rates, allowing for longitudinal analysis of recovery.

Methods and results

Mice challenged by systemic administration of 0.7 LD50 BoNT/A developed physiological signs of botulism, such as respiratory depression and reduced voluntary running activity, that persisted for an average of 8-12 d. Studies in isolated hemidiaphragm preparations from intoxicated mice revealed profound reductions in nerve-elicited, tetanic and twitch muscle contraction strengths that recovered to baseline 21 d after intoxication. Despite apparent functional recovery, neurophysiological parameters remained depressed for 28 d, including end plate potential (EPP) amplitude, EPP success rate, quantal content (QC), and miniature EPP (mEPP) frequency. However, QC recovered more quickly than mEPP frequency, which could explain the discrepancy between muscle function studies and neurophysiological recordings. Hypothesizing that differential modulation of voltage-gated calcium channels (VGCC) contributed to the uncoupling of QC from mEPP frequency, pharmacological inhibition studies were used to study the contributions of different VGCCs to neurophysiological function. We found that N-type VGCC and P/Q-type VGCC partially restored QC but not mEPP frequency during recovery from paralysis, potentially explaining the accelerated recovery of evoked release versus spontaneous release. We identified additional changes that presumably compensate for reduced acetylcholine release during recovery, including increased depolarization of muscle fiber resting membrane potential and increased quantal size.

Discussion

In addition to identifying multiple forms of compensatory plasticity that occur in response to reduced NMJ function, it is expected that insights into the molecular mechanisms involved in recovery from neuromuscular paralysis will support new host-targeted treatments for multiple neuromuscular diseases.

Botulinum Toxins and Zinc: From Theory to Practice-A Systematic Review

OBJECTIVE

The aims of this study were to determine whether zinc supplementation affects botulinum toxin's effect and longevity and to establish a transition from the molecular to the clinical aspect.

METHODS

We conducted a systematic review in which we included all published studies on PubMed and Embase using the combination of the following terms: "zinc" AND (botox OR botulinum OR onabotulinumtoxinA OR abobotulinumtoxinA OR incobotulinumtoxinA).

RESULTS

From the 260 yielded articles, 3 randomized control trials and 1 case report were retained. Three of them found a significant improvement with zinc supplementation in the toxin's effect and longevity. This was observed in neurological conditions and cosmetic uses.

CONCLUSIONS

Zinc supplementation could be an interesting asset in the potentialization of botulinum neurotoxin effect and longevity. Larger clinical trials and objective measurement tools should be used to further defining the role of zinc in maximizing botulinum neurotoxin effect.

Antidotal treatment of botulism in rats by continuous infusion with 3,4-diaminopyridine

Botulinum neurotoxins (BoNTs) are highly potent, select agent toxins that inhibit neurotransmitter release at motor nerve terminals, causing muscle paralysis and death by asphyxiation. Other than post-exposure prophylaxis with antitoxin, the only treatment option for symptomatic botulism is intubation and supportive care until recovery, which can require weeks or longer. In previous studies, we reported the FDA-approved drug 3,4-diaminopyridine (3,4-DAP) reverses early botulism symptoms and prolongs survival in lethally intoxicated mice. However, the symptomatic benefits of 3,4-DAP are limited by its rapid clearance. Here we investigated whether 3,4-DAP could sustain symptomatic benefits throughout the full course of respiratory paralysis in lethally intoxicated rats. First, we confirmed serial injections of 3,4-DAP stabilized toxic signs and prolonged survival in rats challenged with 2.5 LD50 BoNT/A. Rebound of toxic signs and death occurred within hours after the final 3,4-DAP treatment, consistent with the short half-life of 3,4-DAP in rats. Based on these data, we next investigated whether the therapeutic benefits of 3,4-DAP could be sustained throughout the course of botulism by continuous infusion. To ensure administration of 3,4-DAP at clinically relevant doses, three infusion dose rates (0.5, 1.0 and 1.5 mg/kg∙h) were identified that produced steady-state serum levels of 3,4-DAP consistent with clinical dosing. We then compared dose-dependent effects of 3,4-DAP on toxic signs and survival in rats intoxicated with 2.5 LD50 BoNT/A. In contrast to saline vehicle, which resulted in 100% mortality, infusion of 3,4-DAP at ≥ 1.0 mg/kg∙h from 1 to 14 d after intoxication produced 94.4% survival and full resolution of toxic signs, without rebound of toxic signs after infusion was stopped. In contrast, withdrawal of 3,4-DAP infusion at 5 d resulted in re-emergence of toxic sign and death within 12 h, confirming antidotal outcomes require sustained 3,4-DAP treatment for longer than 5 d after intoxication. We exploited this novel survival model of lethal botulism to explore neurophysiological parameters of diaphragm paralysis and recovery. While neurotransmission was nearly eliminated at 5 d, neurotransmission was significantly improved at 21 d in 3,4-DAP-infused survivors, although still depressed compared to naïve rats. 3,4-DAP is the first small molecule to reverse systemic paralysis and promote survival in animal models of botulism, thereby meeting a critical treatment need that is not addressed by post-exposure prophylaxis with conventional antitoxin. These data contribute to a growing body of evidence supporting the use of 3,4-DAP to treat clinical botulism.

Application of botulinum toxin in pregnancy and its impact on female reproductive health

Introduction: Botulinum toxin (BoNT) is a protein secreted by the anaerobic Gram-negative bacterium Clostridium botulinum. Among the seven known subtypes, type A is the most commonly used in women to treat diseases. It primarily blocks presynaptic release of acetylcholine at the neuromuscular junction, resulting in temporary muscle paralysis; thus, it is suitable for treating dystonia and other systemic diseases. BoNT is used widely for treating diseases that persist throughout, and may worsen during, pregnancy, such as cervical dystonia and achalasia. Thus, it is important to investigate whether BoNT injection during pregnancy causes side effects in pregnant women, fetuses, or newborns.Areas covered: This review highlights the efficiency and safety of BoNT injection in pregnancy. and assessed current literature with respect to the use of BoNT for disease treatment during pregnancy.Expert opinion: BoNT injection does not increase the risk of complications in pregnant women and fetuses. However, the use of BoNT to treat disease during pregnancy requires fully informed consent from patients. In addition, further research is needed to determine how to reduce the side effects of BoNT injection during pregnancy (e.g., by improving drug composition, or adjusting the amount of BoNT or the injection interval).

Comparison of the efficacy of onabotulinumtoxinA and abobotulinumtoxinA at the 1: 3 conversion ratio for the treatment of asymmetry after long-term facial paralysis

BACKGROUND

Botulinum toxin A injection into the nonparalyzed side is used to treat asymmetry resulting from facial palsy. OnabotulinumtoxinA and abobotulinumtoxinA units are not equivalent. The authors compared the conversion ratio of 1:3 in patients with facial palsy.

METHODS

Fifty-five patients (age, 16 to 67 years; 43 women) with longstanding facial palsy were randomly treated with either onabotulinumtoxinA (n = 25) or abobotulinumtoxinA (n = 30) injections into the nonparalyzed side. Adverse effects, facial symmetry, subjective satisfaction, and Facial Disability Index were assessed after 1 and 6 months.

RESULTS

The incidence of adverse effects was higher with abobotulinumtoxinA (93.3 percent versus 64.0 percent; p = 0.007). Clinical scores of the nonparalyzed side decreased after 1 month and increased again at 6 months, with no between-group differences. Scores of the paralyzed side were lower in the onabotulinumtoxinA group before treatment, but similar in both groups thereafter. The paralyzed side scores increased after 1 month, and at 6 months were still higher than the pretreatment scores in both groups. Subjective assessment improved at all time points compared with pretreatment scores and differed between the two groups only at 1 month, when the abobotulinumtoxinA group was a bit too paralyzed. The physical function and social/well-being function subscales of the Facial Disability Index did not differ between the two groups.

CONCLUSIONS

Both toxins efficiently reduced asymmetry in patients with facial palsy. Adverse effects were higher with abobotulinumtoxinA at an equivalence ratio of 1:3.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

A double-blind, randomised, crossover trial of two botulinum toxin type a in patients with spasticity

Background

Botulinum toxin type A (btxA) is one of the main treatment choices for patients with spasticity. Prosigne® a new released botulinum toxin serotype A may have the same effectiveness as Botox® in focal dystonia. However, there are no randomized clinical trials comparing these formulations in spasticity treatment. The aim of our study was to compare the efficacy and safety of Prosigne® with Botox® in the treatment of spasticity.

Methodology/Principal Findings

We performed a double-blind, randomized, crossover study consisting of 57 patients with clinically meaningful spasticity. The patients were assessed at baseline, 4 and 12 weeks after Prosigne® or Botox® administration. The main outcomes were changes in the patients’ Modified Ashworth Scale (MAS), Functional Independence Measure (FIM) and Pediatric Evaluation of Disability Inventory (PEDI) scores and adverse effects related to the botulinum toxin. Both of the toxins were significantly effective in relieving the level of spasticity in adults and children. There were no significant differences found between the Prosigne® and Botox® treatments regarding their MAS, FIM and PEDI scores. Likewise, the incidence of adverse effects was similar between the two groups.

Conclusion

Our results suggest that Prosigne® and Botox® are both efficient and comparable with respect to their efficacy and safety for the three month treatment of spasticity.

Trial Registration

ClinicalTrials.gov NCT00819065.

Emerging opportunities for serotypes of botulinum neurotoxins

Background: Two decades ago, botulinum neurotoxin (BoNT) type A was introduced to the commercial market. Subsequently, the toxin was approved by the FDA to address several neurological syndromes, involving muscle, nerve, and gland hyperactivity. These syndromes have typically been associated with abnormalities in cholinergic transmission. Despite the multiplicity of botulinal serotypes (designated as types A through G), therapeutic preparations are currently only available for BoNT types A and B. However, other BoNT serotypes are under study for possible clinical use and new clinical indications; Objective: To review the current research on botulinum neurotoxin serotypes A-G, and to analyze potential applications within basic science and clinical settings; Conclusions: The increasing understanding of botulinal neurotoxin pathophysiology, including the neurotoxin’s effects on specific neuronal populations, will help us in tailoring treatments for specific diagnoses, symptoms and patients. Scientists and clinicians should be aware of the full range of available data involving neurotoxin subtypes A-G.

A guide to dosing in the treatment of cervical dystonia and blepharospasm with Xeomin®: a new botulinum neurotoxin A

Xeomin(®) (incobotulinumtoxinA; Merz Pharmaceuticals, Frankfurt am Main, Germany) was first introduced in Germany for movement disorders in 2005. In 2010, it was approved for use in the United States by the FDA for the treatment of cervical dystonia (CD) and blepharospasm. It is a unique botulinum type A formulation free of any complexing proteins and contains only the pure 150 kD neurotoxin. Thus, the formation of neutralizing antibodies is not induced even after long-term treatment. The purpose of this report is to review the safety profile and dosing schedule for Xeomin for the treatment of CD and blepharospasm. The recommended dose for patients with CD is 120 U/treatment, with administration intervals normally between 3 and 6 months. However, clinical studies have found Xeomin to be safe and effective at doses up to 400 U in both previously treated and treatment-naïve patients. The recommended starting dose in patients with blepharospasm is 2.5-5.0 U/injection site. Patients can be switched using a 1:1 conversion ratio from Botox(®) (onabotulinumtoxinA, Allergen Inc., Irvine, CA, USA) to Xeomin without any loss of efficacy or safety concerns. Xeomin does not differ from Botox in terms of its potency, onset, diffusion profile, or duration and waning of effect. It is the only botulinum treatment that is stable for up to 3 years at room temperature. Xeomin offers a new and important treatment option for movement disorders.

[Botulinum toxin in the treatment of adult spasticity. An interdisciplinary German 10-point consensus 2010]

Spasticity is one of the major causes of functional impairment in adults with lesions of the central nervous system. For instance, approximately 30% of post-stroke patients suffer from different degrees of spasticity with possible consecutive impairments. Numerous studies or meta-analyses showed that local injections of botulinum toxin in spastic muscles lead to dose-dependent reduction in muscle tone and improvement of passive movements (e. g. facilitated care), especially following repeated injections.However, country-specific regulations and patient-remote administration in German health care often do not allow adequate provision of this therapy. Thus, the present consensus statement based on the EBM analyses of the published international literature tries to highlight recent advances and the standard in the field of local spasticity treatment, aiming to facilitate communication between the decision makers and German reimbursement institutions in health care. Prior to initiation of BoNT-A injections, patient-oriented goals should be identified in a multiprofessional context to assure realistic goals for this specific treatment and patient expectations. In Germany for the treatment of focal spasticity following stroke three products have been approved: Botox® (Pharm Allergan, Ettlingen), Dysport® (Ipsen Pharma, Ettlingen) and Xeomin® (Merz Pharma, Frankfurt/Main). For all preparations safety has been repeatedly shown. Functional improvements have also been illustrated for selected patients concerning hand/arm function and gait. The dose per muscle and the selection of muscles to be injected have to be individualized according to the patient's symptoms and should be accompanied by modern neurorehabilitative therapies such as redression or repetitive activation of the injected and antagonistic muscles.

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.

Retrospective evaluation of the dose equivalence of Botox(®) and Dysport (®) in the management of blepharospasm and hemifacial spasm: a novel paradigm for a never ending story

Botox(®) and Dysport(®) are the preparations of botulinum neurotoxin most widely used for therapeutic purposes. Several studies have addressed the topic of the equivalency ratio (D/B ratio) to be used in clinical practice and whether a reliable value exists is still a matter of debate. To this purpose, we ideated a novel paradigm by retrospectively examining the patients affected by hemifacial spasm and blepharospasm. We compared the pairs of treatments with a switch from one brand to the other undergone by the same patient in consecutive sessions with overlapping clinical outcome. Out of 2006 treatments, we found 51 treatment pairs. D/B ratio was extremely variable (range 1.2-13.3) and in most cases (65%) it was between 1:3 and 1:5. In conclusion, even if the 1:4 ratio might be reliable for clinical purpose, a true bioequivalence between Dysport(®) and Botox(®) might not exist due to the intrinsic difference in their pharmacokinetic properties.

Double-blind, randomised, parallel group pilot study comparing two botulinum toxin type A products for the treatment of blepharospasm

Botulinum neurotoxins (BoNTs) are the primary treatment for focal dystonias such as blepharospasm. Several different BoNT products are available in various countries. Given the variability in manufacturing, formulation, and unit doses of BoNTs, it is important to compare the profiles of products from different manufacturers. This double-blind, randomised, parallel-group pilot study compared the efficacy and safety of the BoNT type A product Xeomin® from Merz to BOTOX® from Allergan. Subjects (n = 65) were randomly assigned to receive one or the other BoNTA in a 1:1 proportion at a dose equal to that of their most recent treatment (≥20 U/eye). Symptoms were assessed on the Blepharospasm Disability Index (BSDI), Jankovic Rating Scale (JRS), and Patient Global Assessment (PGA) scale at 4 and 8 weeks. Both BoNTA products reduced scores on the BSDI and JRS (no statistically significant difference, tendency toward greater improvements with BOTOX® than Xeomin® at 4 and 8 weeks). A post hoc analysis showed a significantly greater number of BOTOX® treated patients reaching a responder threshold of 4 points on the total BSDI score and 0.67 points on the BSDI mean item score. No significant differences between products were noted in PGA and adverse events at the doses used in this study.

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.

OnabotulinumtoxinA for treatment of chronic migraine: results from the double-blind, randomized, placebo-controlled phase of the PREEMPT 1 trial

OBJECTIVES

This is the first of a pair of studies designed to assess efficacy, safety and tolerability of onabotulinumtoxinA (BOTOX) as headache prophylaxis in adults with chronic migraine.

METHODS

The Phase III REsearch Evaluating Migraine Prophylaxis Therapy 1 (PREEMPT 1) is a phase 3 study, with a 24-week, double-blind, parallel-group, placebo-controlled phase followed by a 32-week, open-label phase. Subjects were randomized (1:1) to injections every 12 weeks of onabotulinumtoxinA (155 U-195 U; n = 341) or placebo (n = 338) (two cycles). The primary endpoint was mean change from baseline in headache episode frequency at week 24.

RESULTS

No significant between-group difference for onabotulinumtoxinA versus placebo was observed for the primary endpoint, headache episodes (-5.2 vs. -5.3; p = 0.344). Large within-group decreases from baseline were observed for all efficacy variables. Significant between-group differences for onabotulinumtoxinA were observed for the secondary endpoints, headache days (p = .006) and migraine days (p = 0.002). OnabotulinumtoxinA was safe and well tolerated, with few treatment-related adverse events. Few subjects discontinued due to adverse events.

CONCLUSIONS

There was no between-group difference for the primary endpoint, headache episodes. However, significant reductions from baseline were observed for onabotulinumtoxinA for headache and migraine days, cumulative hours of headache on headache days and frequency of moderate/severe headache days, which in turn reduced the burden of illness in adults with disabling chronic migraine.

OnabotulinumtoxinA for treatment of chronic migraine: results from the double-blind, randomized, placebo-controlled phase of the PREEMPT 2 trial

OBJECTIVES

This is the second of a pair of studies designed to evaluate the efficacy and safety of onabotulinumtoxinA (BOTOX) for prophylaxis of headaches in adults with chronic migraine.

METHODS

PREEMPT 2 was a phase 3 study, with a 24-week, double-blind, placebo-controlled phase, followed by a 32-week, open-label phase. Subjects were randomized (1:1) to injections of onabotulinumtoxinA (155U-195U; n = 347) or placebo (n = 358) every 12 weeks for two cycles. The primary efficacy endpoint was mean change in headache days per 28 days from baseline to weeks 21-24 post-treatment.

RESULTS

OnabotulinumtoxinA was statistically significantly superior to placebo for the primary endpoint, frequency of headache days per 28 days relative to baseline (-9.0 onabotulinumtoxinA/-6.7 placebo, p < .001). OnabotulinumtoxinA was significantly favoured in all secondary endpoint comparisons. OnabotulinumtoxinA was safe and well tolerated, with few treatment-related adverse events. Few patients (3.5% onabotulinumtoxinA/1.4% placebo) discontinued due to adverse events.

CONCLUSIONS

The results of PREEMPT 2 demonstrate that onabotulinumtoxinA is effective for prophylaxis of headache in adults with chronic migraine. Repeated onabotulinumtoxinA treatments were safe and well tolerated.