Head-to-Head Study Finds Myobloc® (Botulinum Toxin Type B) Injectable Solution as Safe and Effective as Botulinum Toxin Type A in Treating Toxin-Naïve Cervical Dystonia Patients
Study of patients with painful movement disorder in neck and head after they received their first botulinum toxin treatment
Malvern, PA, USA – April 11, 2008 – Myobloc® (Botulinum Toxin Type B) Injectable Solution was found to be as safe and effective as botulinum toxin type A in treating toxin-naïve cervical dystonia patients in the first head-to-head study of its kind published in the current issue of Movement Disorders. The journal is the official peer-reviewed publication of the Movement Disorder Society.
The international, multi-center trial was designed to evaluate and compare the effectiveness, safety and duration of response between MYOBLOC and botulinum toxin type A in patients with cervical dystonia receiving their first botulinum toxin treatment. The study was designed as a noninferiority trial, which aims to determine if one treatment is therapeutically similar to another.
“This data should reinforce with clinicians that MYOBLOC is a safe and effective option to consider for first-line botulinum toxin use in cervical dystonia patients,” said Mark F. Lew M.D., Professor of Neurology and Director of the Division of Movement Disorders at the University of Southern California. “Patients’ needs vary so it’s important for clinicians to be experienced and able to provide them with treatment/injections of both serotypes of botulinum toxin.” Dr. Lew was not an investigator in this study but has been an investigator in other MYOBLOC research.
Cervical dystonia is a painful and often disabling movement disorder that requires life-long medical management. Also known as spasmodic torticollis, it is a condition that primarily affects the neck. While the exact cause of cervical dystonia is unknown, scientists believe the problem originates in the basal ganglia area of the brain that is instrumental in movement. Depending on the severity of the disease, cervical dystonia can dramatically affect the ability of the patient to lead a normal life. Pain is a common symptom, affecting approximately 75 percent of those with cervical dystonia. The treatment goal is to lessen symptoms of spasms, pain and impaired posture and to improve functionality.
In the double-blind, noninferiority study, 111 patients were randomized to receive doses of either MYOBLOC (10,000 U) or botulinum toxin type A (150 U). The study design reflected standard dosing parameters from European health authorities and in participating European countries. Patients were over age 18 and had cervical dystonia for at least six months. They were evaluated four weeks after the initial dose and followed every four weeks thereafter until loss of effect or withdrawal to assess duration of effect.
The primary outcome measure was the change in the total score of the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) at week four (after one injection). The TWSTRS assessment is a validated rating scale considered to be a reliable measure of the efficacy of botulinum toxin regimens for treating cervical dystonia. The duration of clinical effect was measured by comparing TWSTRS total score across visits. Secondary measures included change in TWSTRS subscale scores (severity, disability, pain), duration of response and safety.
Enrolled patients had total baseline TWSTRS score of >20, with severity at >10, disability >3 and pain >1. The results of the study showed that patients had statistically significant improvements (p<0.0001 versus baseline) in the following areas four weeks after the first injection:
TWSTRS total overall score:
MYOBLOC patients had an 11.0-point improvement
Botulinum toxin type A patients had an 8.8-point improvement
TWSTRS pain subscale:
MYOBLOC patients had a 2.7-point score reduction versus baseline
Botulinum toxin type A patients had a 1.7-point change
TWSTRS disability subscale:
MYOBLOC patients had a 2.9-point score improvement versus baseline
Botulinum toxin type A patients had a 2.5-point change
TWSTRS severity subscale:
MYOBLOC patients had a 5.4-point score change versus baseline
Botulinum toxin type A patients had a 4.7-point change
The effects of MYOBLOC were noninferior to the effects of botulinum toxin type A. None of the differences between MYOBLOC and botulinum toxin type A were significantly different.
In addition, the data demonstrated:
The median time of duration of effect for patients receiving MYOBLOC was 13.7 weeks; for botulinum toxin type A, it was 13.1 weeks (the difference between treatment arms was not significant).
In both patient populations, there were no significant differences in the total number of moderate or severe adverse events, including difficulty swallowing, dry mouth or injection site pain; however, significantly more mild dry mouth was reported for patients receiving MYOBLOC.
Myobloc® (Botulinum Toxin Type B) Injectable Solution is indicated for the treatment of patients with cervical dystonia to reduce the severity of abnormal head position and neck pain associated with cervical dystonia.
Before administering MYOBLOC, physicians should consult the full Prescribing Information. Visit www.myobloc.com.
The most frequently reported adverse events with MYOBLOC are dry mouth, dysphagia, dyspepsia, and injection site pain. These adverse events are generally mild to moderate, transient, self-resolving, and more common with higher doses. Dysphagia is commonly reported with all botulinum toxins in cervical dystonia patients.
Caution should be exercised when administering MYOBLOC to individuals with motor neuron disease (eg, amyotrophic lateral sclerosis), peripheral motor neuropathic diseases (eg, motor neuropathy) or neuromuscular junctional disorders (eg, myasthenia gravis or Lambert-Eaton syndrome). These patients may be at increased risk of clinically significant systemic effects including severe dysphagia and respiratory compromise from typical doses of MYOBLOC. In these patients, rare cases of dysphagia severe enough to cause aspiration pneumonia or to warrant the insertion of a gastric feeding tube have also been reported.
Coadministration of MYOBLOC and aminoglycosides or other agents interfering with neuromuscular transmission (eg, curare-like compounds) should only be performed with caution as the effect of the toxin may be potentiated.
Research was funded by biopharmaceutical firm Solstice Neurosciences, Inc., manufacturer of MYOBLOC, the only FDA-approved botulinum toxin type B available in the United States.
MYOBLOC was the first drug approved in the US to reduce the severity of abnormal head position and the neck pain associated with cervical dystonia. When injected into an affected muscle, botulinum toxin type B inhibits the release of the neurotransmitter, acetylcholine, at the motor nerve terminals to allow it to relax.
Regulatory approvals in the US, EU and Canada were based on the results from randomized, multi-center, double-blind, placebo-controlled studies in adult patients with cervical dystonia.
MYOBLOC is supplied as a ready-to-use, injectable solution in three single-dose vial sizes of 0.5 mL (2,500 U), 1.0 mL (5,000 U), and 2.0 mL (10,000 U). Unopened vials of MYOBLOC have demonstrated stability when stored at 2-8°C, and are approved for a 36-month shelf life in the EU, and a 48-month shelf-life in the US and Canada.
About Solstice Neurosciences, Inc.
Founded in 2004, Solstice Neurosciences, Inc. is a biopharmaceutical company focused on the development, manufacturing, sales and marketing of specialty products. Solstice’s first product, MYOBLOC, represents the only botulinum toxin type B currently available to physicians and patients worldwide. MYOBLOC is sold in the United States and is approved in Canada. It is also distributed and sold in the EU as NeuroBloc. Solstice recently received approval for promotion of botulinum toxin type B in South Korea. For more information about Solstice Neurosciences, Inc., visit www.solsticeneuro.com
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