FDA Clears Incannex To Proceed With Phase 2 Psilocybin-Assisted Therapy Trial For Anxiety

As reported in a recent press release, Incannex Healthcare Inc. IXHL has received approval from the U.S. Food and Drug Administration to proceed with a phase 2 clinical trial investigating its psilocybin formulation, PSX-001, combined with psychotherapy for treating generalized anxiety disorder (GAD). This follows the successful review of the company's Investigational New Drug (IND) application, which detailed the clinical trial protocol and the safety and quality of the investigational drug product.

Previous Positive Results

The trial, named PsiGAD2, builds on the positive results of the initial PsiGAD1 proof-of-concept study conducted at Monash University in Melbourne. PsiGAD1 demonstrated a significant 12.8-point reduction in the Hamilton Anxiety Rating Scale (HAM-A) scores from baseline in the psilocybin treatment group, highlighting the potential of psilocybin-assisted psychotherapy in reducing anxiety symptoms.

Phase 2 Trials

PsiGAD2 aims to replicate and expand on the encouraging outcomes of PsiGAD1. In the previous test, 44% of the psilocybin group experienced over a 50% reduction in HAM-A scores, and 27% achieved remission, significantly outperforming the placebo group.

Incannex submitted the IND application on June 26, 2024 and the FDA completed its review within the allotted 30-day time frame. Approval was granted after a thorough evaluation of the trial protocol, principal investigator and a risk-benefit analysis of the proposed drug. The new trial plans to enroll approximately 94 patients with GAD, including those currently treated with selective serotonin reuptake inhibitors, who meet the study criteria.

Patients will be administered one of two doses of PSX-001 under double-blind conditions. Each patient will undergo two dosing sessions, along with preparatory and integrative psychotherapy sessions. The primary endpoint is the change in HAM-A score two weeks after the second dosing session. Secondary endpoints include quality of life measures, healthcare utilization, electroencephalography (EEG) assessments, and safety and tolerability assessments by monitoring for adverse events.

Company Expansion

In addition to the U.S. approval, PsiGAD2 is under review by the Medicines and Healthcare Products Regulatory Agency (MHRA) in the United Kingdom. Incannex plans to initiate trial activities in the UK concurrently with those in the U.S. The company holds 20 granted patents and over 30 pending applications, and is pursuing U.S. FDA approval and registration for each drug and therapy under development, which represent major global economic opportunities.

Generalized Anxiety Disorder

GAD is characterized by excessive, uncontrollable worry persisting for at least six months. Symptoms include persistent worry, nervousness, restlessness, and difficulty concentrating, leading to significant impairment in daily functioning. GAD affects about 6-9% of the population over a lifetime and approximately 3% annually in countries like Australia and the United States. Effective treatment options remain limited, with many patients experiencing high relapse rates and significant side effects from current therapies.

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