Distant Spread of Toxin Effect
Postmarketing reports indicate that the effects of MYOBLOC and all botulinum toxin products may spread from the area of injection to produce symptoms consistent with botulinum toxin effects. These may include asthenia, generalized muscle weakness, diplopia, blurred vision, ptosis, dysphagia, dysphonia, dysarthria, urinary incontinence, and breathing difficulties. These symptoms have been reported hours to weeks after injection. Swallowing and breathing difficulties can be life threatening and there have been reports of death. The risk of symptoms is probably greatest in children treated for spasticity but symptoms can also occur in adults treated for spasticity and other conditions, particularly in those patients who have underlying conditions that would predispose them to these symptoms. In unapproved uses, including spasticity in children and adults, and in approved indications, cases of spread of effect have occurred at doses comparable to those used to treat cervical dystonia and at lower doses.
Myobloc® (rimabotulinumtoxinB) injection is a sterile liquid formulation of a purified neurotoxin that acts at the neuromuscular junction to produce flaccid paralysis. The neurotoxin is produced by fermentation of the bacterium Clostridium botulinum type B (Bean strain) and exists in noncovalent association with hemagglutinin and nonhemagglutinin proteins as a neurotoxin complex. The neurotoxin complex is recovered from the fermentation process and purified through a series of precipitation and chromatography steps.
MYOBLOC is indicated for the treatment of adults with cervical dystonia to reduce the severity of abnormal head position and neck pain associated with cervical dystonia.
Published Studies Related to Myobloc (Rimabotulinumtoxinb)
[A double-blind comparative study to evaluate the efficacy and safety of NerBloc®
(rimabotulinumtoxinB) administered in a single dose to patients with cervical
dystonia]. [Article in Japanese] 
We conducted a single-dose, placebo-controlled, double-blind, dose-response study
of NerBloc®(rimabotulinumtoxinB) in patients with cervical dystonia (placebo,
2,500 U, 5,000 U, 10,000 U). The primary endpoint, the change in Toronto Western
Spasmodic Torticollis Rating Scale (TWSTRS)-total score at 4 weeks post dose from
baseline, showed a significant improvement in all treatment groups (2,500 U,
5,000 U, 10,000 U) compared with the placebo group...
RimabotulinumtoxinB effects on pain associated with cervical dystonia: results of
placebo and comparator-controlled studies. 
Response rate (RR) and mean improvement (MI) in the pain subscale of the Toronto
Western Spasmodic Torticollis Rating Scale (TWSTRS-PS) from two
placebo-controlled studies and one comparator-controlled study were evaluated to
examine the effect of rimabotulinumtoxinB (BoNT-B) on cervical dystonia (CD)
Pilot study of the safety and efficacy of Myobloc (botulinum toxin type B) for
treatment of axillary hyperhidrosis. 
(botulinum toxin type B) in the treatment of bilateral axillary hyperhidrosis... CONCLUSION: Myobloc (botulinum toxin type B) proved to be safe and efficacious
Double-blind, randomized, placebo-controlled pilot study of the safety and
efficacy of Myobloc (botulinum toxin type B) for the treatment of palmar
placebo-controlled study to report on the safety and efficacy of Myobloc... CONCLUSION: Myobloc proved to be efficacious for the treatment of palmar
RimabotulinumtoxinB versus OnabotulinumtoxinA in the treatment of masseter
hypertrophy: a 24-week double-blind randomized split-face study. 
OnabotulinumtoxinA (BTX-A) in the treatment of masseter hypertrophy... CONCLUSION: Both BTX-A and BTX-B are effective in the treatment of masseter
Clinical Trials Related to Myobloc (Rimabotulinumtoxinb)
Myobloc Atrophy Study [Active, not recruiting]
The present pilot study is designed to assess the extent to which BOTOX and MYOBLOC cause
muscle atrophy in spastic patients. The primary objective is to assess whether there is
statistically significant difference in muscle atrophy between the two groups over a one
Efficacy and Safety Study of MYOBLOC� Followed by Open-Label Multiple-Treatment With MYOBLOC� in the Treatment of Troublesome Sialorrhea in Adult Subjects [Recruiting]
This study will evaluate the efficacy and safety of MYOBLOC in the treatment of Sialorrhea
(drooling), which can be a symptom of many disease conditions. MYOBLOC will be injected
directly into the salivary glands. MYOBLOC has been shown in previous trials to safely
decrease saliva production, thereby demonstrating its potential as a safe and effective
treatment for troublesome sialorrhea.
An Open Label Safety and Immunogenicity Study of MYOBLOC (Neurobloc; Botulinum Toxin Type B) Injectable Solution in Patients With Cervical Dystonia [Completed]
Five hundred patients with a confirmed clinical diagnosis of Cervical Dystonia (CD)are
planned for enrollment into this open label study. These patients will be Type B toxin
naive patients with CD. During this study patients will receive repeat injections of
MYOBLOC when deemed appropriate by the Investigator. However, it will be recommended that
injections occur not more frequently than every 12 weeks. Total duration of exposure to
MYOBLOC will be targeted for at least two years, with potential exposure for up to 7 years
in patients with earliest enrollment
Study of Myobloc in the Treatment of Sialorrhea (Drooling) in Patients With Amyotrophic Lateral Sclerosis (ALS) [Completed]
The purpose of this study is to determine the safety and efficacy of Myobloc in ALS patients
who are having excessive drooling.
The primary goal of the study is to determine if the patient perceives a benefit from the
Myobloc in controlling excessive drooling.
A Multi-Center Study of MYOBLOC for the Treatment of Sialorrhea in Parkinson's Disease Patients [Completed]
Page last updated: 2014-12-01