Background: This
paper reports early results from a clinical trial evaluating a new drug for relapsing-remitting
Multiple Sclerosis (MS)1. The drug – daclizumab – is a designer
antibody manufactured to dampen down the activity of the immune system by
inhibiting a signal called interleukin-2. In Multiple Sclerosis, the immune
system goes awry and attacks cells in the brain. For this reason, several
clinical trials are looking at whether daclizumab is a safe and effective
treatment for MS. The available evidence suggests that daclizumab is effective2-4,
but is it safe to use in the long term?
Methods: The
SELECTED trial aimed to answer this question. Researchers followed 410 patients
across 8 countries who received 150mg of subcutaneous daclizumab injections
every 4 weeks. On average, the patients had been receiving the treatment for
just over 2 years. It follows on from two earlier trials, SELECT and SELECTION,
which were mainly interested in the effectiveness of daclizumab.
Results: Over
the 3-year study period, 76% experienced an adverse event of some kind. 26%
experienced serious adverse events, of which the most common were MS relapse,
disturbances of liver function, pneumonia, and ulcerative colitis. 12% of
patients experienced an adverse event which led them to stop receiving the
treatment, but no patients died during the study period. It is important to
note that the chance of experiencing a side effect with daclizumab may be
slightly underestimated by these results. This is because patients were
excluded from the trial if they had already left because of a previous adverse
event.
Conclusion: The
take home message of the SELECTED trial is that daclizumab appears to have a
similar risk-benefit profile to commonly-used MS drugs such as beta-interferon.
However, we will have to wait a few more years until the end of the 8-year
study period to confirm that daclizumab is safe for clinical use. We will also
need to find out how daclizumab compares to other drugs in head-to-head trials
looking at long-term safety and efficacy.
References:
- Gold,
Ralf, et al. "Safety and efficacy of daclizumab in relapsing-remitting
multiple sclerosis: 3-year results from the SELECTED open-label extension
study." BMC Neurology 16.1 (2016): 1.
- Gold,
Ralf, et al. "Daclizumab high-yield process in relapsing-remitting
multiple sclerosis (SELECT): a randomised, double-blind, placebo-controlled
trial." The Lancet 381.9884 (2013): 2167-2175.
- Giovannoni,
Gavin, et al. "Daclizumab high-yield process in relapsing-remitting
multiple sclerosis (SELECTION): a multicentre, randomised, double-blind
extension trial." The
Lancet Neurology 13.5 (2014):
472-481.
- Kappos,
Ludwig, et al. "Daclizumab HYP versus interferon beta-1a in relapsing
multiple sclerosis." New
England Journal of Medicine 373.15
(2015): 1418-1428.