Safety of daclizumab: 3-year results from the SELECTED study

The paper: 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.

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: 
  1. 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.
  2.  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.
  3. 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.
  4. Kappos, Ludwig, et al. "Daclizumab HYP versus interferon beta-1a in relapsing multiple sclerosis." New England Journal of Medicine 373.15 (2015): 1418-1428.

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