Axial Therapeutics Announces Completion of Enrollment in Global Phase 2b Clinical Trial for AB-2004 for Irritability Associated with Autism

Topline clinical data anticipated in 1Q 2024

First-in-class small molecule therapeutic targets the microbiome gut-brain axis and its role in autism, offering a potential alternative to antipsychotic treatments

WOBURN, Mass.— September 26, 2023 — Axial Therapeutics, a clinical-stage biotechnology company dedicated to the development of gut-targeted, small molecule therapeutics for neurological conditions and oncology, today announced completion of enrollment in the TAPESTRY Autism Study, the Phase 2b clinical trial of its lead product candidate, AB-2004, a first-in-class oral gut-targeted small molecule therapeutic designed to treat irritability associated with autism. The global, randomized clinical trial enrolled 156 children and adolescents with autism. Data from the Phase 2b clinical trial is anticipated in the first quarter of 2024.

“Irritability is one of the most common reasons why caretakers seek my assistance for their children diagnosed with autism. Antipsychotic medications are commonly used as treatment but come with myriad side effects that can limit their use,” said Roger J. Jou, MD, MPH, PhD, Child Psychiatrist, Yale School of Medicine, and Principal Investigator of the Tapestry Autism Study.  “AB-2004 leverages the gut-brain connection; it works in the gut by trapping bacterial byproducts and removing them in the stool, which reduces their absorption into the body and ultimately their negative effect on the brain. I eagerly anticipate the results of the phase 2 clinical trial of AB-2004 to assess the possibility this novel approach reduces irritability associated with autism.”

“We are pleased to announce the successful completion of enrollment in our Phase 2b clinical trial – a critical milestone that brings us closer to our goal of addressing the significant unmet need for a safe and effective therapy to treat irritability in autism that works differently from existing medications,” said Stewart Campbell, CEO of Axial Therapeutics. “On behalf of the team at Axial, I would like to extend our sincere gratitude to the children and adolescents who enrolled in the trial, their families, and caregivers. We also want to thank the clinicians and their staff at over 25 clinical sites who have played an essential role in ensuring that the potential of AB-2004 could be fully explored. We look forward to sharing data in the first quarter of 2024 and bringing forward this innovative therapy to improve the lives of people with autism and their families.”

About the AB-2004 Phase 2b Trial

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 5 to 17 who have been diagnosed with autism and suffer with increased irritability. 156 participants were randomized to receive either AB-2004 or placebo. The primary efficacy endpoint of the study is the mean change in the Aberrant Behavior Checklist Irritability subscale (ABC-I) from baseline to week 8. Key secondary outcome measures include the mean change in the Clinical Global Impression-Severity (CGI-S) from baseline to week 8; and the number of participants who report treatment emergent adverse events from baseline to week 8. The AB-2004 Phase 2b study is being conducted at multiple clinical trial centers in the United States, Australia and New Zealand. More information about the U.S. trial is available at (NCT04895215). To learn more, visit Axial’s clinical trial website.

About AB-2004

AB-2004 is a first-in-class, small molecule 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 “neuroactive microbial metabolites” (NMM®) 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 conducted in an adolescent ASD patient population, AB-2004 was safe and well-tolerated, exhibiting no drug-related serious adverse events. AB-2004 was also shown to reduce several NMM® implicated in autism and showed evidence of improving key co-occurring conditions including irritability and anxiety (Nature Medicine, 2022). 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 biotechnology company dedicated to improving the lives of people with neurological disorders and conditions. The company is a scientific leader in elucidating the biological role of the microbiome-gut-brain axis and its influence on the central nervous system. Harnessing the power of its Microbial Inspired Therapeutics® platform, 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 disease pathology, progression, and symptoms. The company is advancing a pipeline of small molecule drug candidates for conditions with significant unmet patient need, including autism and Parkinson’s disease, and is also pursuing preclinical discovery of gut-targeted therapies in oncology and NASH/fibrosis. Axial’s lead product candidate is AB-2004, a small molecule therapeutic in Phase 2b clinical trials for the treatment of irritability in children with autism. For more information, visit

Contacts for Axial Therapeutics

Maura Gavaghan
Red House Communications

Jeffrey Young, CFO