Corcept Therapeutics’ amyotrophic lateral sclerosis (ALS) drug has shown two-year survival benefit above placebo, despite the trial having failed to achieve its primary endpoint.
In the Phase II DAZALS study (NCT05407324), ALS patients who received 300mg dazucorilant, a selective cortisol modulator, experienced an 87% reduction in the risk of death after two years compared to patients who received placebo.
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This finding is consistent with the 84% reduction in risk of death observed after one year of treatment.
Although DAZALS did not meet its primary endpoint of difference in function, as measured by the ALS Functional Rating Scale – Revised (ALSFRS-R) at the end of the 24-week treatment period, patients who received 300mg of dazucorilant daily did exhibit improved overall survival (OS), a key secondary endpoint. The primary endpoint miss was previously reported in December 2024.
DAZALS is a randomised, double-blind, placebo-controlled Phase II study that enrolled 249 patients to receive either 150mg of dazucorilant, 300mg of dazucorilant or placebo.
The drug continued to demonstrate an acceptable safety profile, with mild to moderate, dose-related, transient abdominal pain being the most common adverse event (AE).
Bill Guyer, Corcept’s chief development officer, said this data paves the way for further research of the candidate.
Guyer said: “Our data demonstrate that dazucorilant markedly reduces mortality in the first years following diagnosis, when people with ALS retain meaningful function and quality of life. We are working with regulators to advance this programme as expeditiously as possible and expect to initiate a pivotal Phase III study later this year.”
Analysis by GlobalData found that clinical research activity in ALS has expanded considerably in recent years. Trial activity reached its highest level in 2025, which accounted for roughly 9% of all studies, suggesting an accelerating interest in novel therapeutic approaches. In terms of clinical trial status, approximately 59% of trials have been completed, 9% are currently ongoing and recruiting participants, while another 9% are planned. A further 5% are ongoing but no longer recruiting, and approximately 17% have been suspended, terminated, or withdrawn.
GlobalData is the parent company of Clinical Trials Arena.
This drive is also being seen in trial success, with AL-S set to advance its monoclonal antibody (mAb), AP-101, to a registrational study after it prolonged survival and delayed ventilatory support after 12 months of treatment compared to those who received placebo for six months then AP-101 for six months in a Phase II trial.
Spinogenix has also seen success with its lead candidate SPG302, which met its primary endpoint in a Phase IIa study of safety and tolerability in the ALS population, with no treatment-emergent serious adverse events (SAEs) reported over a six-month period of daily dosing.
ALS has typically been a challenging indication to treat, but there are now four therapies, and an additional two prodrugs, that have gained approval from the US Food and Drug Administration (FDA).
This includes Biogen and Ionis Pharmaceuticals’ SOD1-targeting antisense oligonucleotide, Qalsody (tofersen), which was granted accelerated approval from the FDA in 2023, despite the VALOR trial failing to meet its primary endpoint of improved ALSFRS-R scores over 28 weeks. The FDA granted the drug approval based on changes in plasma levels of neurofilament light (NfL) protein.
