A comparison of botulinum toxin type A versus botulinum toxin type B for involuntary positioning of the head, or cervical dystonia.

Costa J, Borges AA, Espírito-Santo CC, Ferreira J, Coelho MM, Moore P, Sampaio C

Published Online:

January 21, 2009

Cervical dystonia is the most common form of focal dystonia and is characterized by involuntary posturing of the head. It is frequently associated with neck pain and may lead to physical disability and social withdrawal. Botulinum toxin type A (BtA) has become the first line therapy, however, not all patients respond well to BtA, and 5 to 10% become resistant to it. Botulinum toxin type B (BtB) is a related product that may be an effective alternative to BtA and has the potential to help patients who do not respond to BtA. No completed randomised, controlled trials directly comparing the efficacy and safety of BtA and BtB were identified. Two large trials are underway.

Abstract (click to read)

Background:

Cervical dystonia is the most common form of focal dystonia. It is characterized by involuntary posturing of the head and frequently is associated with neck pain. Disability and social withdrawal are common. Most cases are idiopathic, and generally it is a life-long disorder. In recent years, botulinum toxin type A (BtA) has become first line therapy for cervical dystonia. However, not all patients respond well to BtA, and 5 to 10% become resistant to it. Botulinum toxin B (BtB) is an alternative to BtA and offers the potential to help patients who do not respond to BtA. At present there is no compelling theoretical reason why it should not be as effective as, or even more effective than, BtA.

Objectives:

To compare the clinical efficacy and safety of BtA versus BtB in cervical dystonia.

Search strategy:

Studies for inclusion in the review were identified using the Cochrane Movement Disorders Group trials register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, by handsearching the Movement Disorders Journal and abstracts of international congresses on movement disorders and botulinum toxin, by communication with other researchers in the field, by searching reference lists of papers found using the above search strategies, and by contact with authors and drug manufacturer.

Selection criteria:

Studies were considered eligible for inclusion in the review if they evaluated the efficacy of BtA versus BtB for the treatment of cervical dystonia. Trials must have been randomised and placebo-controlled.

Data collection and analysis:

A paper pro-forma was used to collect data from the included studies using double extraction by two independent reviewers. Each trial was assessed for internal validity by each of the two reviewers. Differences were settled by discussion.
The outcome measures used included improvement in symptomatic rating scales, subjective evaluation by patients and clinicians, changes in pain scores, changes in quality of life assessments, and frequency and severity of adverse events.

Main results:

We cannot give any results since we have only identified two ongoing trials and there are no preliminary results or interim analyses available for them. The full results of these trials are expected in late 2004 or 2005.

Authors' conclusions:

It is currently not possible to make definitive comparisons between BtA and BtB for the treatment of cervical dystonia; uncontrolled comparisons should be regarded with suspicion.

This record should be cited as:

Costa J, Borges AA, Espírito-Santo CC, Ferreira J, Coelho MM, Moore P, Sampaio C. Botulinum toxin type A versus botulinum toxin type B for cervical dystonia. Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD004314. DOI: 10.1002/14651858.CD004314.pub2

Assessed as up to date:

May 5, 2003

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Primary Review Group:

Movement Disorders Group

Health topics:

Neurology > Movement disorders > Dystonia

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

A comparison of botulinum toxin type A versus botulinum toxin type B for involuntary positioning of the head, or cervical dystonia.

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