
Compass Pathways' Phase IIb psilocybin trial shows reduced depression symptoms
UK biotech Compass Pathways revealed this morning that they reached the primary endpoint in a Phase IIb clinical trial of psilocybin therapy.
In the randomized, controlled and double-blind trial, investigators looked at a single dose of Compass’s investigational psilocybin therapy COMP360 for treatment-resistant depression in 233 patients, given alongside psychological support. The trial, which had all patients stopping antidepressants before participating, compared two active doses of COMP360, 25mg and 10mg, against a comparator 1mg dose.
The results showed that there was a “statistically significant and clinically relevant reduction in depressive symptom severity after three weeks,” according to a Compass statement.
While the candidate was generally well tolerated, 179 patients reported at least one adverse event — the most common being headaches, nausea, fatigue and insomnia. There were 12 patients who reported more serious adverse events, such as suicidal behavior, intentional self-injury, and suicidal ideation.
The goal of the trial was to find the appropriate dose for a larger, pivotal Phase III trial, which the biotech expects to begin sometime next year.

“We set out to explore the safety and efficacy of COMP360 psilocybin therapy in treatment-resistant depression, through a rigorous and large-scale trial, and to find an appropriate dose to take to the next stage,” said Compass CEO George Goldsmith in a statement. “With these compelling data, we will urgently progress our clinical development programme and move closer to making this therapy accessible to patients in need, if approved.”