Glatiramer acetate

Glatiramer is an immunomodulator utilized for the treatment and management of multiple sclerosis. Glatiramer acetate is employed in addressing relapsing-remitting multiple sclerosis (RRMS), clinically isolated syndrome (CIS), and active secondary progressive disease. Despite an unclear understanding of its mechanism, the drug seems to influence immune processes associated with MS. It is a mixture of synthetic polypeptides composed of four amino acids.

The dosage for glatiramer acetate is 20 mg s/c once daily or 40 mg s/c 3 times a week (eg, Mon, Wed, Fri) administered at least 48 hours apart.

The mechanism of action is not known but it may:

• inhibit the binding of myelin basic protein antigens to the T-cell receptor (1)
• modulate the phenotype of myelin-autoreactive T-cells

The treatment is well tolerated although a self-limiting systemic reaction (with symptoms such as flushes, palpitations, chest tightness and dyspnoea) was experienced by 48% of patients on glatiramer acetate (vs. 29% on placebo) starting within minutes of injection and lasting up to 30 minutes (2,3). Injection site reactions (including redness, pain, swelling, itching, oedema) were reported in 82% of patients on glatiramer acetate (vs. 48% on placebo).

In 2013, Khan et al performed a phase III, randomized, double-blind study trial including over 1404 patients with RRMS in over 142 sites in 17 countries, compared a high dose of 40 mg glatiramer acetate 3 times per week to placebo over 1 year. This study revealed a 34% reduction in risk of confirmed relapses in those receiving treatment compared to those receiving placebo, 0.331 vs 0.501, p=0.0001. (4)

The summary of product characteristics should be consulted before prescribing this drug.

Reference:

1. Weinstock-Guttman B, Nair KV, Glajch JL, Ganguly TC, Kantor D. Two decades of glatiramer acetate: From initial discovery to the current development of generics. J Neurol Sci. 2017 May 15;376:255-259.
2. Copaxone. Summary of Product Characteristics, UK. Teva Pharmaceuticals Ltd, April 2001.
3. Johnson KP et al (2000). Sustained clinical benefits of glatiramer acetate in relaping multiple sclerosis patients observed for 6 years. Mult Scler, 6, 255-66.
4. Khan O, Rieckmann P, Boyko A, Selmaj K, Zivadinov R., GALA Study Group. Three times weekly glatiramer acetate in relapsing-remitting multiple sclerosis. Ann Neurol. 2013 Jun;73(6):705-13