Could Irregular Clinical Trial Activity Have Predicted Zuranolone’s MDD Rejection?

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September 5, 2023
Could Irregular Clinical Trial Activity Have Predicted Zuranolone’s MDD Rejection?

In August 2023, the Food and Drug Administration (FDA) granted Biogen and Sage Therapeutics the much-anticipated approval for their drug, Zuranolone, to treat postpartum depression. However, this approval came with a significant limitation: it did not include the indication for major depressive disorder (MDD), which holds a significantly larger market potential. This partial approval was overshadowed by the potential lost opportunities for the pharmaceutical companies, triggering stock price implications, major layoffs, and pipeline restructuring.


Cambridge-based Sage Therapeutics, collaborating with Biogen, had high expectations for Zuranolone, branded as Zurzuvae. Aimed at addressing both major depressive disorder and postpartum depression, Zuranolone was promoted as a unique, fast-acting oral treatment administered over 14 days. Sage, having previously received FDA approval in 2019 for brexanolone (marketed as Zulresso) to treat postpartum depression, was eager to tap into the broader depression market with Zuranolone.

‍Red Flags

Before the FDA's decision, STAT Trials Pulse by AppliedXL revealed concerning irregularities within Zuranolone's pivotal MDD trial. By the trial's conclusion, the platform identified substantial fluctuations in patient enrollment—surpassing initial projections by a staggering 157%. There were also inconsistent progressions in trial statuses and multiple changes in the primary completion date, leading to a total delay of 26 months. These early findings indicated potential challenges in the trial's progression and could have acted as warning signals that, as the FDA’s eventual rejection cited, there was a struggle to demonstrate sufficient efficacy.

The Impact

On August 5th, the FDA recognized the positive effects of Zuranolone for postpartum depression but rejected its use for MDD. This refusal was linked to inconsistent clinical trial results. The FDA specifically emphasized the lack of "substantial evidence of effectiveness" for MDD treatment and recommended additional research.

The Fallout

This decision undeniably cast a shadow on Sage's ambition of establishing a blockbuster medication. Although Sage has other drugs under development, the emphasis it placed on Zuranolone, particularly in the MDD market, was unmatched. Previous challenges with Zulresso, mainly its intricate administration process and the pandemic's effects, limited its sales. The constrained approval of Zuranolone suggests that Sage might face difficulties in achieving its ambitious goals. Following this rejection, Sage's stock value plummeted by a staggering 48% in a single day, followed by a layoff of 40% of its workforce and a refocusing of its pipeline, pausing earlier stage programs.

The Bottom Line

The early detection of inconsistencies in Zuranolone's MDD trial by STAT Trials Pulse might have forewarned the drug's unsuccessful submission. For life sciences professionals, such early indicators are crucial for market forecasting and understanding clinical trial health. The rejection of Zuranolone for MDD treatment emphasizes the importance for pharmaceutical companies to closely monitor and address potential issues during clinical trial stages.

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