How Zinbryta works
Zinbryta is a formulation of a monoclonal antibody against the CD25 subunit of interleukin 2 (IL-2) receptors. These receptors are highly expressed on reactive T-cells in MS patients. By selectively targeting the T-cells with CD25, Zinbryta prevents the expansion of CD25-positive, autoreactive T-cells. It further promotes the activity of CD 65-positive natural killer cells, which clean up the already activated CD25-positive T-cells. Therefore, Zinbryta both stops and prevents inflammation caused by CD25-positive T-cells.
In the high-yield formulation, Zinbryta is intended to be administered subcutaneously (beneath the skin) once every four weeks. At this dose, Zinbryta binds to all CD25 receptors within 10 hours and remains bound for 64 days.
History of Zinbryta
Daclizumab was originally pursued for the treatment of acute organ rejection in patients with kidney transplants by Roche under the trade name Zenapax. The medication was available in the U.S. and European Union, but it was withdrawn for commercial reasons. Daclizumab is now called Zinbryta for use in RMS patients. Two clinical trials, DECIDE (NCT01064401) and SELECT (NCT00390221), formed the basis of the biological licence application (BLA) submission to the U.S. Food and Drug Administration (FDA) by Biogen and AbbVie.
The SELECT study compared the effect of different doses of daclizumab (300 mg and 150 mg) to placebo over a one-year period in participants with RMS and showed that the lower dose of daclizumab (150 mg) reduced the relapse rate by 54% compared to placebo.
DECIDE, a Phase 3 study involving 1,841 participants with RMS, showed that Zinbryta reduced the rate of relapses by 45% and also decreased the activity of the disease, as observed in MRI scans, over 144 weeks compared to Avonex, another drug approved for the treatment of RMS.
Next steps for Zinbryta
The European Medicines Agency (EMA) also validated the Marketing Authorization Application for Zinbryta for the treatment of RMS, and a review process by EMA’s Committee for Medicinal Products for Human Use (CHMP) began in March 2015. About a year later, in April 2016, CHMP adopted a positive opinion, recommending marketing authorization in Europe for Zinbryta to treat RMS.