One of the difficulties of interpreting results of clinical trials is that they are mostly drug-company sponsored, are often conducted in ‘ideal’ populations and conditions that don’t necessarily reflect the real world, and often avoid direct head-to-head comparisons of rival drugs.
So, studies that follow up people in real world situations taking the tested medications can often provide very useful insights into how effective these drugs really are. One such recently published study examined administrative records from a large database of insured US patients taking either glatiramer (Copaxone) or interferon beta-1a (Avonex).
The study had the advantage of large numbers of patients, and used an intention to treat analysis (that is, analyzing outcomes based on whether people started treatment on the drug, not whether they kept it going) as well as a persistent use analysis (that is, analyzing outcomes based on whether people stayed on the drug).
It had the drawback of being drug company-sponsored. The findings were strongly in favour of Copaxone. In the intention to treat analysis, those on Copaxone (5%) had half the two year relapse rate of those on Avonex (10%); for those who stayed on the drug, the difference was even larger in favour of Copaxone (2% vs 7%).
In both forms of analysis, those on Copaxone had significantly lower medical costs, implying less illness requiring treatment. The randomized controlled trials have not shown much difference between the various disease-modifying drugs in terms of relapse rate reduction.
This real world study should provide confidence to those taking Copaxone, who are often told the drug is inferior to the interferons, that they have made a sensible choice in opting for this drug, particularly given its better safety and tolerability.