Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.
Copaxone (Hoechst Marion Roussel)
vials containing 20 mg powder for reconstitution
Approved indication: multiple sclerosis
Australian Medicines Handbook Section 16.4.3
Multiple sclerosis has the features of an autoimmune disease. Two of the interferons are approved for treatment, but their mechanism of action is uncertain. This is also true of glatiramer which has been approved for the relapse-remitting type of multiple sclerosis.
Glatiramer is a mixture of polypeptides built from the amino acids, alanine, glutamine, lysine and tyrosine. This mixture reduces allergic encephalomyelitis in animals. Although glatiramer has been studied in clinical trials, there are no human pharmacokinetic data.
The largest study of glatiramer randomised 251 patients to take the drug ora placebo. These patients injected themselves once a day for two years. During this period, glatiramer reduced the mean relapse rate by 29%. This reduction increased to 32% when the trial was extended for several months. During the whole period of the study, 34% of the patients injecting glatiramer had norelapses compared to 25% of the placebo group. Neurological disability was more likely to improve in the patients taking glatiramer.1
In this trial, the most common adverse events were reactions at the injection site. Some patients developed chest pain and facial flushing. Reactive antibodies develop in all patients, but the antibody concentration declines with time. These antibodies do not seem to neutralise the drug.
Although the 29% reduction in relapse rate appears impressive, it is the difference between 1.19 (glatiramer) and 1.68 (placebo).1 The clinical significance of this reduction will require further study. The ability of glatiramer and the interferons to reduce the progression of multiple sclerosis also remains unclear.
