2014年3月26日星期三

Glatiramer acetate (Copaxone)

Glatiramer acetate (Copaxone)

Product name

Copaxone. When it was first developed, the drug was known as copolymer-1.
Glatiramer acetate is one of the disease modifying drugs licensed for relapsing remitting multiple sclerosis. Studies have shown that on average, glatiramer acetate reduces the MS relapse rate by about a third.
Glatiramer acetate is also licensed for clinically isolated syndrome, an individual's first neurologic episode. The 2009 ABN prescribing guidelines state that neurologists may consider the use of beta interferon for people within 12 months of a clinically isolated syndrome when MRI evidence predicts a high likelihood of recurrent episodes.
Glatiramer acetate is prescribed under the Department of Health's Risk-sharing Scheme.

How glatiramer acetate works

Glatiramer acetate is a synthetic combination of four amino acids, resembling the myelin protein surrounding nerve fibres. It is thought to lessen the immune reaction that attacks myelin.

How is glatiramer acetate given?

Glatiramer acetate is injected under the skin daily.
In 2014, the FDA - the American drug regulator - approved a new dose of glatiramer acetate that is injected three times a week.

Side effects and contraindications

Side effects include injection site reactions such as atrophy (leading to permanent indentations in the skin), redness, swelling, itching or some pain at the site. Rarely, glatiramer acetate may cause chest tightness and shortness of breath. Although alarming at the time, this usually passes quickly, only occurs sporadically, and causes no long-term problems.

Research

Less frequent dosing
The GALA study (Glatiramer Acetate Low Frequency Administration) has looked at the efficacy of a higher dose of glatiramer acetate that would be taken three times a week rather than daily. The results have not yet published, but were presented at the AAN (American Academy of Neurology) meeting in March 2013. The study involved 943 people with relapsing MS receiving either the higher dose or a placebo. The improvement in relapse rate was similar to that seen with the daily dosage.
Combination with beta interferon
Research has also looked to see if there is any added benefit from combining disease modifying treatments. A study compared people taking both beta interferon (Avonex) and glatiramer acetate (Copaxone) with people taking either of the drugs on its own. The results showed no difference in effect on progression but the combination and glatiramer alone were both better at reducing the relapse rate and the combination reduced the number of new lesions seen on MRI scans.

References

Johnson KP, et al.
Copolymer 1 reduces relapse rate and improves disability in relapsing-remitting multiple sclerosis: results of a phase III multicenter, double-blind placebo-controlled trial.
Neurology 1995;45(7):1268-1276.

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