MapLight Therapeutics Shares Plunge 40% on Mixed Schizophrenia Trial Data

MapLight Therapeutics, Inc. (NASDAQ:MPLT) shares plummeted approximately 40% on Monday following the release of mixed topline results from its Phase 2 ZEPHYR trial for its schizophrenia treatment, ML-007C-MA. The negative market reaction was driven by the failure of a once-daily dose to achieve its primary goal, despite a twice-daily version of the drug demonstrating statistically significant efficacy.

Trial Delivers Mixed Results

The study's primary endpoint was met by the twice-daily 210/3 mg dose, which showed a statistically significant improvement in the Positive and Negative Syndrome Scale (PANSS) total score compared to a placebo at Week 5. The company reported a mean 4.5-point improvement versus placebo for this cohort.

However, the once-daily 330/6 mg dose did not achieve statistical significance on the same primary endpoint. MapLight noted that while this dose, which results in lower daily exposure, showed numerical improvement over the placebo, the results were not strong enough to be considered statistically significant. This outcome is a significant setback, as once-daily dosing regimens are often viewed as more commercially viable due to improved patient convenience and compliance.

Secondary Endpoints and Safety

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The successful twice-daily arm also achieved significance on key secondary endpoints, including the Clinical Global Impression of Severity and the PANSS positive Marder factor. Notably, this dose demonstrated an improvement in cognitive performance that did not correlate with the change in psychosis symptoms, suggesting an independent cognitive benefit.

Across all doses studied, ML-007C-MA was reported to be generally well tolerated. Treatment-emergent adverse events were described as mostly mild and primarily cholinergic in nature, with no serious adverse events reported. The all-cause discontinuation rate across both active arms was 19.9%.

Path Forward

MapLight Therapeutics plans to engage with the U.S. Food and Drug Administration (FDA) at an End-of-Phase 2 meeting to discuss the data and a potential path forward for ML-007C-MA in schizophrenia. The company stated it is also planning a separate confirmatory trial to further evaluate the effective twice-daily dose and explore other dosing regimens, including a possible once-daily option.