Long-term effect of Copaxone

This retrospective cohort study from Spain aims to analyse the long term outcomes of patients on Copaxone. 

The main headline findings are the following

What does all this mean?

Well at first glance, if I were on Copaxone I would feel pretty reassured by this data but there are a number of factors to consider when looking at the small print. 

Firstly, this study was funded by Teva. Who are Teva I here you ask? Well they are the manufacturers of Copaxone with a vested interest in demonstrating the efficacy of their drug. 

Secondly, (see my previous post on cohort studies) this is a retrospective observational study which comes with its own limitations - we are relying on case note review which is often unreliable

Thirdly, there is no control group to compare with which can be problematic

The study defines 'clinical effectiveness' as being disability free for 5 years but we must remember the natural history of MS - it can take many years to go from RRMS to SPMS and therefore these people may have been simply captured early in their disease course. This becomes more relevant when one thinks about the fact by 9 years follow-up, the study only had data on less than 50% of the cohort.

The MRI data is also a cause for concern - comparing Gd-enhancing lesions from onset of treatment to last date of follow up is deceptive; these lesions do not represent long term acquired disability but recent areas of inflammation. Indeed, we would expect less of these in any case at the later stages of MS as relapses tail off and disability builds up. 

All in all, this is an interesting study, however I would have liked to have seen it done by an independent group who did not have a vested interest in Copaxone. 

Arnal-García C, Amigo-Jorrin MD, López-Real AM, Lema-Devesa C, Llopis N, Rosa RS; XPERIENCIA-5 Study Group. Long-term effectiveness of glatiramer acetate in clinical practice conditions.

J Clin Neurosci. 2014 Sep. pii: S0967-5868(14)00490-1. doi: 10.1016/j.jocn.2014.05.045. [Epub ahead of print]

Glatiramer acetate currently represents one of the main treatments for relapsing-remitting multiple sclerosis (RRMS). However, the information available about its long-term effect in clinical practice is still limited. Thus, this multicenter retrospective cohort study aimed to assess the long-term effectiveness of glatiramer acetate in this setting. 

The study population included RRMS patients treated with glatiramer acetate for at least 5years after its marketing authorization and the primary endpoint was long-term clinical effectiveness, defined as absence of disability progression for at least five consecutive years. A total of 149 patients were included into the study, who had received glatiramer acetate for a mean of 6.9±1.4years (5years, n=149; 6years, n=112; 7years, n=63; 8years, n=32; 9years, n=21). 
More than 85% of patients remained free from disability progression through years 1 to 9 of glatiramer acetate treatment, and 75.2% showed absence of disability progression for at least five consecutive years. Expanded Disability Status Scale (EDSS) scores were maintained, with most patients showing stable/improved EDSS and 92.6% sustaining EDSS <6. Decreased annual relapse rates and increased proportion of relapse-free patients were maintained during the whole glatiramer acetate treatment compared to the year prior to its authorization (p<0.001). The number of gadolinium-enhanced T1-weighted lesions also decreased from pre-glatiramer-acetate assessment to last follow-up whilst on glatiramer acetate (p<0.05). 
In conclusion, administration of glatiramer acetate shows long-term clinical effectiveness for RRMS treatment; its effect under clinical practice conditions slowed disability progression and reduced relapse occurrence for up to 9years.