(Bloomberg) -- Compass Pathways Plc’s experimental therapy based on psilocybin, or so-called magic mushrooms, showed promise in a midstage clinical trial in patients whose depression didn’t improve from other treatments. 

Nearly a quarter of the people treated with the highest dose of Compass Pathways’ drug candidate, called COMP360, saw the severity of their depression reduced after three months, as measured on a scale used by psychiatrists. COMP360 is a patented formulation of the active ingredient in psychedelic mushrooms.

“A high dose of psilocybin works immediately, the day after, for a large number of people, and continues to work,” Compass Chief Executive Officer George Goldsmith said in an interview before the results were made public in a press release. Patients in the trial also all received psychological counseling in addition to the drug.

Goldsmith said the company believes its 233-person test, a Phase 2b study, is the largest and most rigorous ever done on psilocybin. He called the controlled, double-blind trial significant given it involved 10 countries and seven languages. Only people who had tried two or more prior medications for depression and failed to find relief were included.

The results will be of interest to investors in the nascent psychedelics industry, and in particular the U.K.-based company’s top shareholder, Atai Life Sciences NV. Psychedelic stocks have had a rocky road so far this year.

Many startups in the space have business models built around treatment centers or other therapies that tout the promise of psilocybin or similar molecules. While mushrooms have been used for centuries, there are few clinical data on them. 

Read more about why Compass’s results may ripple across its industry 

At the Wonderland conference on the psychedelics industry in Miami on Monday, some participants on a panel addressed the potential for Compass’s results to have a ripple effect. 

“If the data is positive from Compass, there will definitely not be a funding crunch,” said Patrick Trucchio, a biotech analyst at H.C. Wainwright & Co., before the release of the trial results. 

Goldsmith declined to comment on whether its results could be extrapolated to natural psilocybin found in psychedelic mushrooms, saying those contain other compounds and don’t have the precise dosing and purity of COMP360, which involves a crystal form in capsules. 

Final Approval

The company needs an even larger study before it can seek final regulatory approval. Goldsmith said that study could begin next year if the U.S. Food and Drug Administration agrees, and Compass could seek final approval by 2024 or 2025. 

The medicine has already received the agency’s “breakthrough therapy” designation, which is meant to speed up the drug-development process. Compass estimates that more than 100 million people worldwide have treatment-resistant depression, and as many as 30% attempt suicide.

There were five patient withdrawals from the trial at the highest dose, compared with about twice as many people on the lower doses who left the trial. Most patients reported at least one mostly mild or moderate side effect, including headache, nausea, fatigue and insomnia.

There were also 12 people in the study who exhibited suicidal behavior or thoughts, or who showed intent to harm themselves. This shows the importance of having therapy alongside psilocybin-based treatments, Goldsmith said. The trial included “integration” sessions to help patients process their experience, as well as follow-up sessions. 

Read more about why psychedelics are drawing new interest now

Goldsmith said some of the troubled behavior was among the people who hadn’t actually responded to COMP360. Among three participants who exhibited suicidal behavior, two didn’t initially respond to the treatment, while none of the patients with suicidal thoughts had responded. It’s possible that it may have been an effect of their underlying condition -- or even the fact that the drug had failed to help them -- rather than the drug itself, he said.

“This is not a panacea,” he said. “People have such high expectations. And for some, this might be the last thing they think they can try.” 

©2021 Bloomberg L.P.