Dazucorilant shows significant survival benefit in Phase 2 ALS trial

People with amyotrophic lateral sclerosis (ALS) who received a high dose of the experimental therapy dazucorilant had a significantly higher chance of survival than patients given a lower dose or no treatment.

That’s according to new analyses of data from the DAZALS Phase 2 clinical trial (NCT05407324), which failed to meet its main goals of showing that Corcept Therapeutics‘ dazucorilant could slow disease progression over about six months of treatment. Long-term data spanning the trial’s main and extension portions showed that people given the high dose had an 87% lower risk of death over two years compared with those who never received the therapy.

“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,” Bill Guyer, Corcept’s chief development officer, said in a company press release. “We are working with regulators to advance this program as expeditiously as possible and expect to initiate a pivotal Phase 3 study later this year.”

ALS is marked by the death and degeneration of motor neurons, the nerve cells that control movement. Dazucorilant is designed to slow disease progression by modulating the activity of the stress hormone cortisol, which can lead to inflammation and toxicity to nerve cells following chronic exposure. By changing this hormone’s activity, the therapy aims to dampen inflammation and help improve nerve cell survival.

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Trial’s extension portion reveals survival benefit

The DAZALS study enrolled nearly 250 adults with ALS, who were randomly assigned to take one of two doses of oral dazucorilant (150 or 300 mg), or a placebo, for about six months.

The main goal was to determine whether dazucorilant would significantly slow disease progression, as assessed with the ALS Functional Rating Scale-Revised (ALSFRS-R). Results announced in 2024 showed it missed this goal, with disease progression scores showing no significant difference between patients given the therapy and those given a placebo.

But despite missing its main objective, some positive signals emerged: Over the six-month trial, none of the patients given 300 mg dazucorilant died, whereas five patients given a placebo did — a statistically meaningful difference.

After completing the main trial, participants had the option to enter an open-label extension, in which all are being treated with high-dose dazucorilant and monitored for long-term outcomes.

Corcept previously announced long-term findings indicating that patients who received high-dose dazucorilant for one year had an 84% lower risk of death than patients who never received the drug (i.e., patients who got a placebo in the original study then opted not to enter the long-term extension).

The new analyses cover data out to two years.

An analysis compared outcomes in patients who received high-dose dazucorilant for more than six months in either the main trial or the extension with outcomes in patients who received low-dose dazucorilant or a placebo for more than six months in the original study but did not enter the extension. High-dose dazucorilant again showed a statistically significant survival improvement, with the risk of death being reduced by 64% at one year and 61% at two years.

Safety data from the long-term extension have been consistent with earlier findings. The most commonly reported side effect in patients given dazucorilant was abdominal pain, which was usually temporary.

Corcept noted that abdominal pain appears to be dose-dependent, and the company is running additional studies to optimize the dose and minimize side effects while maximizing efficacy.