Daclizumab (trade name Zinbryta) is a therapeutic humanized monoclonal antibody which was used for the treatment of adults with relapsing forms of multiple sclerosis (MS).

[7] A 2013 Cochrane systematic review concluded that there was insufficient evidence to determine the efficacy of daclizumab relative to placebo in people with relapsing-remitting MS and, prior to its being discontinued, the need to investigate longer lengths of treatment and follow-up.

[11] The European Medicines Agency (EMA) originally approved the drug without any contraindications apart from known hypersensitivity,[12] but required Biogen to implement a hepatic risk management guide for physicians.

An EMA review concluded that the medicine poses a risk of serious and potentially fatal immune reactions affecting the brain, liver and other organs.

It is expected that daclizumab, like other antibodies, is degraded by proteases to peptides and finally amino acids, and that it does not interact with cytochrome P450 liver enzymes.

[16] Anti-Tac had been discovered by Thomas A. Waldmann, M.D., chief of the Metabolism Branch at the National Cancer Institute and his team, and they had conducted animal studies and a small clinical trial of anti-Tac in people with T-cell leukemia, with promising results, but people quickly developed their own antibodies rejecting the mouse protein; Waldman, and his colleagues then approached Protein Design Labs to humanize the antibody.

[21] In August 2005, PDL and Biogen Idec agreed to collaborate to develop daclizumab in indications outside the fields of organ rejection and respiratory disease.

[30] In May 2016 the FDA approved daclizumab for the treatment of relapsing multiple sclerosis in adults in 2016 under the trade name Zinbryta, with requirements for postmarketing studies and to submit a formal Risk Evaluation and Mitigation Strategy.