Axial Therapeutics Doses First Subjects in Global Phase 2b Clinical Trial for Irritability Associated with Autism Spectrum Disorder (ASD)

Advancement of first program from Axial platform into a randomized Phase 2b clinical trial signifies key milestone for company

Trial is enrolling approximately 195 autistic adolescents at clinical trial sites in the United States, Australia and New Zealand

Phase 2 trial is based on positive results from open-label Phase 1b/2a trial that demonstrated a favorable safety profile for AB-2004 as well as improvement in irritability scores

Woburn, Mass., November 30, 2021 – Axial Therapeutics, a clinical-stage biopharmaceutical company dedicated to improving the lives of people with neurological conditions, today announced that the first subjects have successfully received their first dose in the company’s global Phase 2b clinical trial for lead candidate, AB-2004, a gut-targeted, molecular therapeutic that is being studied for alleviating the irritability associated with Autism Spectrum Disorder (ASD). The subjects received their first dose of either AB-2004 or placebo at CNS Healthcare in Orlando, FL and Optimal Clinical Trials in Auckland, New Zealand, respectively.

“In keeping with Axial’s mission to fundamentally improve the management of neurological conditions through our focus on the microbiome gut-brain axis, we are truly excited to progress the clinical development of AB-2004 with the dosing of our first subjects in this double-blinded Phase 2b study,” said A. Stewart Campbell, Ph.D., chief executive officer of Axial Therapeutics. “We are proud of our team for their continued commitment to improving the lives of children with autism, and thank the investigators at our global study sites for their collaboration in successfully advancing our first-in-class, molecular therapeutic into Phase 2 development.”

Approximately 1 in 54 children in the U.S. and 1 in 160 children worldwide have been identified with ASD according to the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO), respectively. Core traits of autism include altered social interaction, communication, and the presence of stereotyped repetitive behaviors. Co-occurring conditions that impact quality of life are extensive and diverse, and include irritability, anxiety, Attention Deficit Hyperactivity Disorder (ADHD), allergies, autoimmune disorder, neuroinflammation, and epilepsy. Physicians have reported that irritability impacts a majority of the autistic pediatric population. The presentation of irritability associated with autism can vary with severity and age and can be caused by a broad array of different factors, including lack of sleep, the inability to communicate pain and discomfort, and mental health conditions.

“In studying autism for many years, I have seen many children and their families struggling to manage irritability, anxiety, and other challenges co-occurring with autism,” said Eugene Arnold, M.D., MEd, professor emeritus, Department of Psychiatry and Behavioral Health, The Ohio State University College of Medicine. “AB-2004 offers potential hope of a new therapeutic option for autism-related irritability that might improve patients’ daily lives by avoiding the side effects and risks of the currently available medications for irritability of autism. I am excited to see this program advance further into the clinic.”

“The ASD community is in need of safe and effective options for managing anxiety and irritability or distress,” said Honey Heussler, Associate Professor, Child Health Research Centre, University of Queensland (Australia). “AB-2004, with its gut-targeted mechanism of action has the potential to fill this unmet need. I look forward to continued study of AB-2004 and the outcomes of the Phase 2b trial.”

AB-2004 Phase 2b Trial designed to assess efficacy, safety, and tolerability

The Phase 2b trial is a global, randomized, double-blind, placebo-controlled study evaluating the efficacy, safety, and tolerability of AB-2004 in children aged 13 to 17 who have been diagnosed with autism and gastro-intestinal symptoms. The study will enroll an estimated 195 patients who will receive low or high doses of AB-2004 or placebo.

The primary efficacy endpoint of the study is the mean change in irritability using the Aberrant Behavior Checklist (ABC) from baseline to week 8 for AB-2004 high dose. Key secondary outcome measures include the mean change in the ABC-I score (Irritability) from baseline to week 8 for AB-2004 low dose; the mean change in the Clinical Global Impression-Severity (CGI-S) from baseline to week 8 for AB-2004 high and low dose; and the number of participants who report treatment emergent adverse events from baseline to week 8.

AB-2004 clinical trial sites continue to open

The AB-2004 Phase 2b study will be conducted at approximately 20 clinical trial centers in the United States and approximately seven sites in Australia and New Zealand. To date, Axial has activated 13 sites in the U.S., and two sites in Australia/New Zealand combined. The Phase 2b study is expected to generate topline data in 2023. More information about the U.S. trial is available at, identifier NCT04895215.

About AB-2004

AB-2004 is a first-in-class, molecular therapeutic that targets the microbiome gut-brain axis and its role in autism. AB-2004 has a unique mechanism of action that selectivity sequesters certain bacterially derived metabolites in the gut before they enter the bloodstream and reach the brain. Axial’s gut-targeted approach minimizes the potential for side effects due to a lack of systemic exposure to the drug.

Axial is evaluating AB-2004 in a Phase 2b clinical trial based upon a large body of existing human safety data. In a Phase 1b/2a clinical trial, AB-2004 was safe and well-tolerated, exhibiting no drug-related serious adverse events. AB-2004 was also shown to reduce several key microbial metabolites implicated in autism and showed evidence of improving key co-occurring conditions including irritability and anxiety. Formulated as a powder that can be mixed with food, AB-2004 offers convenient oral dosing for the ASD community.

About Axial Therapeutics

Axial Therapeutics is a clinical-stage biopharmaceutical company dedicated to improving the lives of people with neurological conditions. The company is the scientific leader in the biological role of the microbiome gut-brain axis and its influence on the central nervous system. Harnessing its unique expertise in the microbiome, Axial is developing small molecule drugs with defined mechanisms of action that act on new targets to mitigate the impact of metabolites and bacteria in the gut linked to neurological disorders and disease pathology, progression, and symptoms. The company is advancing a pipeline of microbiome-inspired therapeutics for conditions with significant unmet patient need, including autism and Parkinson’s disease, and is also pursuing pre-clinical discovery of gut-targeted therapies in oncology. Axial’s lead product candidate is AB-2004, a molecular therapeutic in Phase 2 clinical trials for the treatment of irritability in children with autism. For more information, visit

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