The FDA ( U.S. Food and Drug Administration ) has expanded the approved use of Dysport ( AbobotulinumtoxinA ) for injection for the treatment of spasticity in adults, based on its supplemental Biologics License Application ( sBLA ) in lower limb spasticity.
In July 2015, Dysport was approved for the treatment of upper limb spasticity in adults. In July 2016, Dysport was approved to treat pediatric patients with lower limb spasticity aged two and older, making it the first and only botulinum toxin that the FDA approved for this indication.
In a phase III, multi-center, prospective, double-blind, randomized placebo-controlled study, adult patients treated with Dysport following a stroke or traumatic brain injury showed improvement in muscle tone at the ankle joint, measured by the mean change from baseline on the Modified Ashworth Scale ( MAS ) at week 4.
The duration of response for the majority of patients within the study was between 12-16 weeks.
In this study, some patients experienced a longer duration of response ( approximately 20 weeks ).
The degree and pattern of muscle spasticity at the time of re-injection may necessitate alterations in the dose of Dysport and muscles to be injected.
Repeat Dysport treatment should be administered when the effect of a previous injection has diminished, but no sooner than 12 weeks after the previous injection.
Lower limb spasticity impacts a person’s movement. In adults, approximately one in three stroke patients, one in three patients with spinal cord injury, one in six patients with traumatic brain injury, and two in three patients with multiple sclerosis will develop lower limb spasticity.
Adult patients with cerebral palsy also commonly experience spasticity in their lower limbs.
Dysport and all Botulinum toxin products have a Boxed Warning which states that the effects of the Botulinum toxin may spread from the area of injection to other areas of the body, causing symptoms similar to those of botulism.
Those symptoms include swallowing and breathing difficulties that can be life-threatening.
Dysport is contraindicated in patients with known hypersensitivity to any Botulinum toxin preparation or to any of the components; or in the presence of infection at the proposed injection site(s); or in patients known to be allergic to cow’s milk protein.
A phase III, multi-center, prospective, double-blind, randomized placebo-controlled study has evaluated the efficacy and safety of Dysport for the treatment of lower limb spasticity in a population of 381 adult patients ( 253 received Dysport and 128 received placebo ).
Patients had lower limb spasticity ( MAS score more than 2 in the affected ankle joint for toxin naïve patients or MAS score more than 3 in the affected ankle joint for toxin non-naïve patients at least four months since the last Botulinum toxin injection in the affected lower limb ) and were at least six months post-stroke or post-traumatic brain injury.
Patients were randomized to Dysport 1000 Units ( N=125 ), Dysport 1500 Units ( N=128 ), or placebo ( N=128 ) injected intramuscularly into the gastrocnemius-soleus muscle complex located in the calf.
In the study, at least one additional lower limb muscle was injected, according to the clinical presentation. Some of the lower limb muscles injected during the study included: tibialis posterior, flexor digitorum longus, and/or flexor hallucis longus.
There was improvement in both the mean change from baseline in MAS score at the ankle joint at week 4 [ LS mean change from baseline on MAS treatment difference versus placebo were: -0.5 for placebo, -0.6 for Dysport 1000 Units ( NS6 ), and -0.8 for Dysport 1500 Units ( p less than 0.05 ) ].
Dysport 1500 Units injection resulted in a statistically significant improvement in muscle tone and spasticity at the ankle joint. The duration of response for the majority of patients within the study was between 12-16 weeks. Some patients experienced a longer duration of response ( approximately 20 weeks ).
The most common adverse reactions ( greater than or equal to 5% and greater than placebo in either Dysport group ) in adults with lower limb spasticity for Dysport 1000 Units, Dysport 1500 Units, and Placebo, respectively, were: falls ( 9%, 6%, 3% ), muscular weakness ( 2%,7%, 3% ), pain in extremity ( 6%, 6%, 2% ).
Muscular weakness was reported more frequently in women ( 10% ) treated with 1500 Units of Dysport compared to men ( 5% ).
Spasticity is a condition in which there is an abnormal increase in muscle tone or stiffness in one or more muscles, which might interfere with movement.
Spasticity is usually caused by damage to nerve pathways in the brain or spinal cord that control muscle movement, and may occur in association with cerebral palsy, spinal cord injury, multiple sclerosis, stroke, and brain or head trauma.
In adults, approximately one in three stroke patients, one in three patients with spinal cord injury, one in six patients with traumatic brain injury, and two in three patients with multiple sclerosis will develop lower limb spasticity.
Lower limb spasticity commonly involves spasticity in the gastrocnemius and soleus muscle complex located in the calf. These calf muscles, during walking, work to raise the heel from the ground.
Symptoms of spasticity may include increased muscle tone, rapid muscle contractions, exaggerated deep tendon reflexes, and/or muscle spasms.
The degree of spasticity can vary from mild muscle stiffness to severe, painful, and uncontrollable muscle spasms. ( Xagena )
Source: Ipsen, 2017