A scientist quit Stanford to chase a new way to treat depression. He just shared an early sign that his approach could work.

• Alto Neuroscience is focused on developing precision medicine for mental health.
• On Tuesday, the company announced some promising signs for its treatment ALTO-100.

In 2019, Dr. Amit Etkin left Stanford University to pursue a new way to treat psychiatric disorders like depression and post-traumatic stress disorder.

While many treatments for these disorders were developed to treat wide swaths of people, Etkin said he believed there's a more-efficient way to treat patients. He's hoping to develop drugs that help sets of patients who have subtypes of a psychiatric condition.

That's why in 2019, Etkin founded Alto Neuroscience, a private biotech company that uses biological measurements — called biomarkers — to develop drugs for mental illnesses like depression and PTSD. Biomarkers have caught on recently as a way for companies to develop tailored treatments for depression and other conditions.

"The way we develop drugs, the way we deploy drugs in the clinic, all presume nothing about the patient," Etkin said.

He said trial results from Alto were "the first of a series of studies, of a series of efforts," to change that approach.

On Tuesday, Alto announced one of its treatments, ALTO-100, showed promising signs that it could help people with major depressive disorder. The results were shared in a press release and came from a midstage trial that didn't compare ALTO-100 with a placebo, so there's more work to do.

In the trial, Alto separated patients into groups with poor cognition and good cognition, based on a test the company developed, Etkin said.

The company theorized that ALTO-100 would help the group with poor cognition more — and that's what happened in the trial. Those patients saw their depression symptoms improve more than the other group that got the drug.

The trial also tested ALTO-100 in people with PTSD. The company hasn't shared those results.

Dr. Rebecca Strawbridge, a lecturer at the Institute of Psychiatry, Psychology & Neuroscience at King's College London, told Insider there's still uncertainty around the results because the study was small and had no placebo arm.

She said the study appeared to "show encouraging findings for advancing towards a more-personalized treatment approach for depression, in that people who had been flagged as more likely to respond did respond better to the intervention."

Alto said it started a bigger study of ALTO-100 this month, which will include a placebo arm. The company plans to announce results from that trial in the first quarter of 2024, meaning that turning ALTO-100 into an approved drug is years away, at best.

Etkin said Alto planned on conducting a number of midstage trials across its various medicines in 2024.

"That'll really be the year of precision psychiatry readouts from us," he told Insider.