Access to a second PBS-listed abobotulinumtoxin A (Dysport) is now available for the treatment of moderate-severe spasticity of the upper limb in children with cerebral palsy from two years of age.

The PBS listing is supported by evidence from a phase III study recently published in Developmental Medicine and Child Neurology.

The study comprised 210 children, aged two to 17 years, from 32 sites across eight countries. They were randomised to receive abobotulinumtoxin A injections at either 8 U/kg or 16 U/kg or a subtherapeutic dose of 2 U/kg for the active controls.

Existing physiotherapy or occupational therapy were continued throughout the study and children also received a personalised home-exercise therapy program.

Initial treatment with the therapeutic doses of abobotulinumtoxin A led to a reduction in upper limb spasticity that was maintained across subsequent treatment cycles.

All groups showed clinically relevant improvements in the Physician Global Assessment (PGA) of treatment response.

“Efficacy benefits were generally sustained over the 1-year study with repeat treatment cycles of abobotulinumtoxin A plus home exercises, where doses of 8U/kg or 16U/ kg abobotulinumtoxin A were given in the upper limb muscles,” the study said,

Treatment also appeared to be well tolerated with no evidence of adverse events increasing with higher doses. Mild muscle weakness was the only treatment-related adverse event reported in more than one child in any group.

“The mean time to retreatment in subsequent treatment cycles was 19.4 weeks after the second injection and 17.4 weeks after the third injection (doses combined),” the study said.

However, many children did not require reinjection until 34 weeks or later.

Noting the limitation of a lack of a true control group, the study said the data nevertheless formed the basis of regulatory approval for abobotulinumtoxin A in several countries.

Dr Chris Ingall, a consultant paediatrician from Lismore in NSW, who runs the only non-metropolitan injection service in Australasia, welcomed the PBS listing.

He told the limbic the PBS listing for Ipsen’s Dysport meant more choice for patients.

“I do know that this expanded market will be embraced because Dysport gives a particularly long duration of effect which is the reason I choose it. I’ve stuck with Dysport because it is more effective for longer.”

Dr Ingall said the delay on PBS approval for the upper limb was baffling given the upper limb was at least as important as the lower limb.

“In essence you use both your legs even if there is one which is shortened and spastic in say a calf muscle. You will still use it. It’s not like it becomes without function; it’s just the function isn’t optimal,” he said.

“Whereas with an arm, it is very easy, particularly for children to just tuck it in their pocket or use it as a prop if it’s not as functional as the other side. And that’s from infancy on.”

“So that if you can inject an arm to allow it to assume a functional posture, that allows them then to use an occlusion technique on the more able limb so that children have to use the affected limb for life skills like feeding themselves, etc. It really does come back to the use it or lose it.”

He said botulinum toxin was a great facilitator – allowing more therapy to happen with less pain.

“It not only allows for orthotics and splints to be used, it allows for occupational therapy and physiotherapy in particular to the affected limbs to be painless and more effective.”

Rehabilitation medicine specialist Associate Professor Anupam Datta Gupta also agreed the PBS listing was good news.

“We’ve had Botox in the market for a long time, so we are using it for those groups of patients. But it’s always good to have a couple of brands so that we can see which one is cost effective, there is talk about some working longer…it is a good thing not to have one player.”

Associate Professor Gupta, from the Queen Elizabeth Hospital in Adelaide, has previously highlighted anomalies in the PBS listing of botulinum toxin therapy.

“Stroke survivors faced great difficulty in walking due to leg spasticity, but this was not approved by PBS. We argued about this and other discrepancies in use of Botulinum toxin in Australia. PBS significantly expanded the indications based on patients’ needs and the emerging evidence,” he told the limbic.