Canada-based psychedelic therapy company Cybin is edging closer to demonstrating results across all six cohorts from its highly anticipated Phase II trial investigating CYB003 in major depressive disorder (MDD) after the company initiated dosing in the sixth and final group.

Dosing in the first five cohorts – at 1mg, 3mg, 8mg, 10mg, and 12mg – demonstrated no serious adverse events or subject discontinuations.

The company expects dosing completion in Q3 2023, with topline efficacy data in Q3/Q4 2023.

The Phase I/IIa trial (NCT05385783) is a randomised, placebo-controlled, double-blind study investigating CYB003 – a deuterated analogue of psilocybin – in patients with moderate to severe MDD. The study was amended in February 2023 to include healthy volunteers for the sub-therapeutic dose cohorts.

Cybin also added a bioequivalence cohort. The study will evaluate the tolerability, safety, pharmacokinetics and pharmacodynamics, and psychedelic effects of ascending oral doses of CYB003.

MDD affects approximately 17.3 million adults in the US. Anti-depressants are the current treatment of choice but their use has steadily increased over the past decade.

By 2036, the revenue for CYB003 is expected to reach an annual total of $416m in the US, according to GlobalData.

Cybin CEO Doug Drysdale said: “As we begin the final dose escalation cohort in our Phase II study, we are moving closer than ever towards our goal of determining an optimal dose for CYB003 and assessing CYB003’s potential as a safe and effective therapeutic for people in need of improved treatment options for major depressive disorder.”

“We are very pleased with the excellent safety data for CYB003 in participants to date and look forward to reporting Phase II efficacy topline data later this year and preparing for data submission to the FDA for pivotal studies.”

The company also has another candidate, CYB004 (deuterated dimethyltryptamine), in a Phase I trial for the treatment of generalised anxiety disorder.