Dysport (abobotulinumtoxinA) for multiple sclerosis

Last updated April 11, 2022, by Marisa Wexler, MS
Fact-checked by Ines Martins, PhD

What is Dysport for MS?

Spasticity, when muscles are abnormally stiff and tight and prone to involuntary muscle spasms, is one of the most common problems arising from nervous system damage in people with multiple sclerosis (MS). It is estimated to affect up to 90% of people with the disease.

Dysport (abobotulinumtoxinA) is an injectable medication approved in MS for easing spasticity in the upper and lower limbs. It is marketed by Ipsen.

The medication also is being developed as a treatment for neurogenic detrusor overactivity (NDO), or overactive bladder, in MS patients. NDO, which results in urinary incontinence, is considered one of the MS symptoms with the most negative impact on quality of life.

Therapy Snapshot

How does Dysport work?

Dysport is a form of purified botulinum toxin type A, a neurotoxic protein produced by the bacteria Clostriudium botulinum. It interferes with the communication between nerves and muscle cells by blocking a key neurotransmitter.

The toxin specifically prevents the chemical messenger acetylcholine from being released by nerve cells at the neuromuscular junction, where nerve and muscle cells communicate. This leads to a temporary loss of signals that make the muscles contract. It may help with conditions characterized by overactive muscles, such as spasticity and neurogenic detrusor overactivity.

Who with MS can take Dysport?

The U.S. Food and Drug Administration has approved Dysport for the treatment of spasticity of the upper or lower limbs in adults and children ages 2 and up.

Dysport was first approved in 2015 for upper limb spasticity in adults, with approvals for lower limb spasticity granted in the following years — in 2016 for children, and in 2017 for adults. The regulatory agency extended Dysport’s indications to include upper limb spasticity in children in 2020.

The therapy also is indicated in the U.S. for treating cervical dystonia, a condition characterized by spasms in the neck muscles, and glabellar lines, which are the horizontal wrinkles that stretch across the forehead.

Dysport first became available in the U.K. in the early 1990s and has since received marketing authorization in more than 70 countries.

Who should not take Dysport?

People with a known allergy to botulinum toxin, a cow’s milk protein, or any other component in Dysport’s formulation should not be given the medication. The therapy also should not be administered if there is an infection at the injection site(s).

Dysport should be used with caution in elderly patients, as older individuals may have an increased risk of certain side effects, like falls and physical weakness.

How is Dysport administered?

Dysport is given via intramuscular injection directly into the affected muscles. Dosing is tailored based on the specific muscles that are being targeted for treatment. Other key factors for dosing are the severity of spasticity and the individual’s history of reactions to Dysport or similar botulinum toxin medicines.

The medication is available as a dry powder that must be diluted in an appropriate liquid solution. Single-use vials are available in two strengths:

• 300 units, which must be diluted in 0.6–3 mL of liquid
• 500 units, for dilution in 1–5 mL of liquid

In adults, the recommended dosing is 500–1,000 units for upper limb spasticity and 1,000–1,500 units for spasticity of the lower limbs. The total dose per treatment session, including upper and lower limbs, should not exceed 1,500 units, and re-treatment sessions should take place at least 12 weeks or about three months apart.

Importantly, the strength in each Dysport unit cannot be compared with other preparations of botulinum toxin products; thus, Dysport doses are not interchangeable with other preparations.

In children, the recommended dose for upper limb spasticity is 8–16 units/kg per limb, and the total dose per treatment session should not exceed 16 units/kg or 640 units, whichever is lower. For lower limb spasticity, the suggested dose is 10–15 units/kg per limb, and the total dose must not exceed 15 units/kg for one limb or 30 units/kg for both limbs, or 1,000 units in total.

The total dosage given per treatment session in children, including upper and lower limbs, also should not exceed 30 units/kg or 1,000 units. Additionally, treatment sessions for children should be at least three months apart.

Common side effects of Dysport

The most common side effects of Dysport in adults with spasticity include:

• muscle weakness
• falls
• pain in the lower extremities

The most common side effects in children with spasticity include:

• upper respiratory tract infections
• inflammation of the pharynx, called pharyngitis
• nasopharyngitis, or the common cold
• fever
• cough

Spread of toxin effect

The effects of Dysport can spread beyond the site of injection, which can result in muscle weakness and other symptoms consistent with the toxin’s effects. These symptoms may develop hours to weeks after the initial injection, and they can cause life-threatening breathing and swallowing difficulties.

The risk of these effects is thought to be highest in children, and for adults with underlying conditions that make them more susceptible to these effects (e.g., amyotrophic lateral sclerosis, known as ALS, or myasthenia gravis).

People who experience difficulty with speech, swallowing, or breathing after receiving treatment with Dysport are advised to seek immediate medical attention.

Allergic reactions

Serious allergic reactions, which can include anaphylaxis, swelling, and difficulty breathing, have been reported in patients treated with Dysport. If such a reaction occurs, Dysport should be immediately discontinued, and the patient should be given appropriate therapy to manage the reaction.

Pregnancy and breastfeeding

The effects of Dysport in pregnant people have not been adequately studied in clinical trials, but animal data suggest that the medication can cause harm to a developing fetus. It also is not clear if Dysport can pass into breast milk or increase the risk of side effects in nursing infants.

According to its label, Dysport should only be used during pregnancy or breastfeeding if the potential benefits outweigh the risks.

Dysport in clinical trials

Adults with spasticity

The approvals of Dysport for adults with upper and lower limb spasticity were based on data from two Phase 3 clinical trials. Both trials enrolled participants whose spasticity resulted from stroke or brain trauma; these patients were randomly assigned to receive a single injection of Dysport or a placebo.

The first trial (NCT01313299) involved 243 adults with upper limb spasticity who received a single treatment session with Dysport (500 or 1,000 units) or a placebo, administered in the elbow, wrist, or finger flexor muscles.

Results from the trial after one month showed that spasticity in the target muscles was significantly lowered in the Dysport group, with effects lasting up to 20 weeks (about five months) in some patients. Spasticity in the various muscles was assessed with the Modified Ashworth scale (MAS), a standardized measure of muscle tone.

In the similarly designed second trial (NCT01249404), 381 participants with lower limb spasticity were given Dysport (1,000 or 1,500 units) or a placebo in the gastrocnemius-soleus muscle complex in the calf.

The higher dose significantly outperformed the placebo at lowering MAS scores in the calf muscles after one month,  trial results showed. Further data from the trial’s long-term extension (NCT01251367), in which participants received up to four additional treatment sessions — at least 12 weeks apart, with the study extending to at least 48 weeks, or just over a year — indicated that improvements in spasticity were maintained in the long term.

Children with spasticity

For children and adolescents, the approvals were based on results from two Phase 3 trials that enrolled more than 400 patients, ages 2 to 17, with limb spasticity due to cerebral palsy.

One trial (NCT02106351) involved 209 patients with upper limb spasticity who were given either a placebo or Dysport at one of three dosages — 2, 8, or 16 units/kg. The medication was injected into the wrist or elbow flexor muscles in four treatment cycles. Results of the trial showed that patients given the two higher doses had significantly greater improvements in MAS scores at six weeks into every cycle. These effects were maintained about four months after each injection in most patients.

The other Phase 3 trial (NCT01249417) included 235 children with lower limb spasticity, in whom the injections were given into the calf muscles. These participants received a placebo or Dysport at doses of either 10 or 15 units/kg per leg. Compared with the placebo, Dysport treatment led to a significantly greater decline in MAS scores in the ankle plantar flexor muscle after four and 12 weeks, trial results showed.

MS-related neurogenic detrusor overactivity

NDO is a condition that commonly affects MS patients. It is characterized by an overly active detrusor, the muscle that helps to squeeze urine out of the bladder during urination. As a result of NDO, patients may experience unexpected and frequent urine leakage.

A Phase 2 clinical trial (NCT01357980) tested Dysport, injected into the detrusor muscle, in 47 people, ages 18–70, with NDO related to MS or spinal cord injury. Patients were given a placebo or 750 Units of Dysport, administered in either 15 or 30 injection sites.

The injections were carried out over a single day, and patients were monitored for 96 days, or just over three months. Results indicated that Dysport treatment reduced urinary incontinence episodes by more than 75% after 12 weeks, regardless of the mode of administration.

Ipsen then launched two Phase 3 trials — CONTENT1 (NCT02660138) and CONTENT2 (NCT02660359) — designed to test Dysport against a placebo for treating NDO caused by MS or spinal cord injury. Both trials were terminated early due to slow patient recruitment.

Available data was culled from 483 participants across both studies, who were given a placebo or Dysport at doses of 600 or 800 Units. The data suggest that patients receiving the placebo experienced, on average, around 12 fewer urinary incontinence episodes per week at six weeks after treatment. By comparison, participants given Dysport reported about 21–24 fewer incontinence episodes per week at the same time point.

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