Spanish Review Report Questions Development of MS Drug Zinbryta

In March 2018, manufacturers of the multiple sclerosis (MS) drug Zinbryta (daclizumab) initiated a worldwide withdrawal of the drug because of reports of brain inflammation linked to the drug. Now, a recent report on the drug in a Spanish medical journal raises questions about the drug-approval process.

Zinbryta Goes Through Long Period of Development

Zinbryta (daclizumab), which was co-developed by Biogen and AbbVie, is an antibody that targets the interleukin-2 (IL-2) receptor on immune cells that become activated in MS patients. It interferes with the signaling to help slow the relapse rate and reduce the number of new lesions in the brain. The drug is a long-acting injection that is self-administered by the patient every month.

Following a long period of development, Zinbryta was approved by the FDA in 2016 for use in relapsing MS patients. In 2007, the results for the CHOICE trial, a Phase 2, clinical trial were reported. According to the results, the drug met its primary endpoint in relapsing multiple sclerosis (MS) patients being treated with interferon beta. Patients receiving the drug showed a significant reduction in the number of new or enlarged lesions at week 24.

In 2011, the manufacturers announced the results from the SELECT trial, which found that the drug significantly reduced annual relapse rates by 54 percent in the 150 mg dose arm, and 50 percent in the 300 mg dose arm, compared to placebo and reduced MS lesions. Researchers stated the results showed that the drug was a promising new approach to treating MS.

Side effects in the studies included serious infections and liver function abnormalities, which occurred more often in patients taking the drug than those taking placebo.

FDA Approves Zinbryta for MS, but a Year Later It’s Removed from the Market

In May 2016, the FDA approved the use of Zinbryta for the treatment of adults with relapsing forms of MS. The FDA reported the approval was based on the results of two clinical trials showing Zinbryta’s efficacy, but noted that the drug should be reserved only for patients with an inadequate response to two or more other MS drugs, “because Zinbryta has serious safety risks, including liver injury and immune conditions.” The FDA further required a black-box warning on the drug and ordered that it be distributed only under a “Risk Evaluation and Mitigation Strategy,” so that it would be used only by a small number of patients.

At that time, however, the FDA didn’t mention the risk of brain inflammation. In 2018, the European Medicines Agency (EMA) announced that it was reviewing the safety of the medication after receiving eight reports of serious inflammatory brain disorders. About a month later, the manufacturers announced a worldwide withdrawal of the drug, stating that it was in the best interest of patients and was based on reports of brain inflammation.

The recent Spanish review report addressed how the drug was developed, noting that while it was effective against MS, it presented safety problems early on. The authors of the report concluded that the development of new drugs for MS “must be contingent upon maintaining or improving the risk-benefit profile with respect to those already in use.”