Incannex Healthcare submits proposals for phase two psychedelics study to treat generalised anxiety disorder

Clinical-stage pharmaceutical development company Incannex Healthcare (ASX: IHL) has completed a Human Research Ethics Committee submission for a phase 2a Psi-GAD study, which combines the administration of psilocybin (or magic mushroom-based tablets or capsules) with specialised therapy to patients with generalised anxiety disorder (GAD).

Incannex has also worked with regulatory specialist Camargo Pharmaceuticals on the submission of a comprehensive information package to the United States Food and Drug Administration (FDA) for the purpose of requesting a pre-investigational new drug (IND) meeting.

The submission includes questions to the US FDA to seek regulatory clarity on Incannex’s planned phase 2b Psi-GAD pivotal clinical trial.

Two US based organisations, Compass Pathways and Usona Institute, have made IND submissions for psilocybin therapy with the FDA in the past, but for depression indications. Both programs have received breakthrough designation from the FDA due to the large effect size on patients.

Research team

The two submissions made by Incannex follow an extensive and collaborative trial design process with a research team from Incannex partner Monash University, led by principal investigator Dr Paul Liknaitzky and co-investigators Professor Suresh Sundram and Professor Murat Yucel.

The wider team includes national and international experts in psychedelic-assisted therapies, psychometric evaluation, qualitative research and therapist training.

Human Research Ethics Committees review all research proposals involving human participants to ensure they meet ethical standards and guidelines.

Incannex’s phase 2a trial is due to commence later this year while a larger, multi-site and pivotal phase 2b trial is planned to commence in 2022.

Phase 2a design

The phase 2a study has been designed as a randomised triple-blind, active-placebo-controlled trial involving 72 participants who will be subject to two psilocybin or active-placebo dosing sessions and up to 11 non-drug, specialist psychotherapy sessions over a period of 10 weeks.

It will be conducted by Monash’s School of Psychological Sciences and the Department of Psychiatry at neuroscience research platform BrainPark (within the university’s Turner Institute for Brain and Mental Health).

Primary outcomes for the trial have been listed as safety, efficacy and tolerability, while secondary outcomes are quality of life, functional impairment and co-morbidities.

A preliminary analysis of patient data will be conducted by an independent data safety monitoring board after 30 patients have completed primary endpoint assessment.

The analysis results will be used in the planning of the larger phase 2b trial and opening of an IND application.

Debilitating condition

Generalised anxiety disorder is characterised by diffuse, excessive, debilitating anxiety which is not restricted to any specific environmental circumstances and occurs almost daily for at least six months.

In any 12-month period, around 3% of adults in the US and Australia are believed to suffer from the condition, equating to an estimated 9 million people in the US and approximately 1 million people in Australia.

First line treatment options include cognitive behavioural therapy and anti-depressants, while benzodiazepines are utilised as a second-line, short-term option.

Incannex said that manifestations of GAD are often debilitating for moderate to severe patients and existing treatments show limited efficacy with less than 50% of patients achieving remission alongside high relapse rates, highlighting a significant unmet need