Positive results from phase 2a trial with psychedelics for major depressive disorder

In the first placebo-controlled efficacy study completed to date investigating a short-term psychedelic for depression, intravenous (IV) N,N-dimethyltryptamine (DMT)—SPL026—with adjunctive therapy for the treatment of major depressive disorder (MDD) primary endpoint and showed a statistically significant and clinically meaningful reduction in depressive symptoms 2 weeks after dosing compared to placebo.

The Phase 2a study included 2 phases and enrolled 34 participants with moderate/severe MDD who were dosed with a 21.5 mg IV infusion of SPL026 resulting in a 20 to 30 minute psychedelic experience. In the blinded, randomized, placebo-controlled phase, the primary endpoint was to assess the efficacy of a single dose of SPL026 with supportive therapy (N=17) versus placebo with therapy (N=17) at 2 weeks post-dose. Subsequently, all study participants were enrolled in an open-label phase in which they received a single dose of SPL026 with supportive therapy and were followed for 12 weeks.

“The results are exciting for psychiatry. We now have the first evidence that SPL026 DMT, in combination with supportive therapy, can be effective for people suffering from MDD,” said David Erritzoe, MD, clinical psychiatrist at Imperial College London and principal investigator of the phase 1/2a trial . “For patients unfortunate enough to receive little benefit from existing antidepressants, the potential for rapid and lasting relief from a single treatment, as demonstrated in this study, is promising.”

Efficacy was assessed using the Montgomery-Asberg Depression Rating scale (MADRS). Independent reviewers who were not present for dosing and blinded to overall treatment assessed MADRS. Compared to placebo, SPL026 with supportive therapy showed a statistically significant and clinically meaningful reduction in depressive symptoms after 2 weeks, with a difference of -7.4 points in MADRS (p=0.02). Analysis of key secondary endpoints showed a rapid onset of antidepressant effect 1 week post-dose, with a statistically significant difference in MADRS score between the active and placebo groups of -10.8 (p=0.002).

“We are pleased that a significant number of patients benefited from the treatment in our study. SPL026 with supportive therapy was shown to have a significant antidepressant effect that was rapid and durable, with a remission rate of 57% at 3 months after a single dose of SPL026,” said Carol Routledge, Chief Medical and Scientific Officer of Small Pharma. “It was encouraging to see that SPL026 showed a favorable safety and tolerability profile in MDD patients in this trial, consistent with our Phase 1 trial. The results are clinically meaningful and allow us to progress to an international multi-site phase 2b study in which we aim to further investigate the efficacy and safety profile of SPL026 in a larger MDD patient population.”

George Tziras, Chief Executive Officer of Small Pharma said of the data: “MDD affects the lives of hundreds of millions of people worldwide. The magnitude of the unmet need indicates the importance of exploring alternative new treatments. Our goal is to develop patented, scalable, and reimbursable short-term psychedelics with supportive therapy to meet this need. I’m thrilled with our top-line results, which demonstrate proof-of-concept for SPL026 and provide encouraging support for our broader portfolio. I would like to thank every patient who participated in this study, as well as their families, the study investigators, study site staff, and everyone who contributed to the successful completion of this study.”


1. Small Pharma Reports Positive Phase IIa Trial Results of SPL026 in Major Depressive Disorder. Press release. Edmonton Journal. 25 January 2023. https://edmontonjournal.com/globe-newswire/small-pharma-reports-positive-top-line-results-from-phase-iia-trial-of-spl026-in-major-depressive-disorder

Positive results from phase 2a trial with psychedelics for major depressive disorder

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