Cybin turns in phase 2 depression data on psychedelic treatment, investors tune out

Cybin has put out more data on its psychedelic treatment for depression, presenting findings from a phase 2 trial that suggest there may be benefits to repeat administration but not to increasing the dose.

One month ago, Cybin shared interim phase 2 data on the effect of a single 12-mg dose of CYB003 in people with major depressive disorder (MDD). The therapy is a deuterated analog of the psychedelic prodrug compound in magic mushrooms known as psilocybin. The study linked CYB003 to significant improvements over placebo on the MADRS depression rating scale three weeks after treatment. 

Now, Cybin has shared more results from the study, including data on the 16-mg dose cohort and the effect of giving a second dose. The analysis, which covers 24 people on CYB003 and 10 patients on placebo, lacks evidence that better MADRS results are achieved by increasing the dose to 16 mg.

After three weeks, 53% of patients in the 12-mg cohort experienced a 50% reduction in MADRS scores, compared to 44% of their counterparts in the higher-dose arm. The rates of remission, defined as a score of 10 or less on MADRS, were almost identical, with 20% in the 12-mg arm playing off against 22% in the 16-mg group.

Cybin reported a mean reduction in MADRS from baseline versus placebo of 14 points in the 12-mg arm, a result the biotech said caused the study to achieve its primary endpoint, and 13.75 points in a pooled analysis of both doses. MADRS is listed as a secondary endpoint on The Columbia Suicide Severity Rating Scale is named alongside safety measures as a primary endpoint.

The biotech also shared data on the effect of giving a second dose of CYB003. MADRS scores improved by 5.8 points after the administration of a second 12-mg dose of CYB003 at six weeks. The remission rate rose from 20% to 79% after a second dose. 

Cybin compared the data favorably to the effects of other antidepressants. However, such cross-trial comparisons can be unreliable. Cybin’s MADRS results are in line with the effect seen in a double-blind, randomized clinical trial. 

“We are delighted to share that CYB003 achieved the primary efficacy endpoint in this study and showed rapid and statistically significant improvements in depression symptoms after a single dose, with a clear incremental benefit of a second dose, resulting in four out of five patients in remission from their depression at six weeks,” Cybin CEO Doug Drysdale said in the release.

Investors didn't appear to share Drysdale's enthusiasm, however. The biotech's stock dropped 8% to 43 cents as the markets opened on Thursday.