Xylo Bio Achieves Clinical-Stage Milestone with XYL-1001, a Highly Selective Neuroplastogen Targeting Major Depressive Disorder

BOSTON, Sept. 15, 2026 /PRNewswire/ -- Xylo Bio, a clinical-stage biotechnology company developing novel neurotherapeutics for psychiatric and neurological disorders, today announced the first participants dosed in its Phase 1 clinical study of XYL-1001, a novel, selective 5-HT2A agonist being developed for major depressive disorder (MDD).

The randomized, double-blind, placebo-controlled Phase 1 study is being conducted in Australia and is designed to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamic activity of XYL-1001 across single ascending dose (SAD) and multiple ascending dose (MAD) cohorts in healthy volunteers. The study incorporates several translational biomarkers developed to characterize pharmacodynamic engagement and support future clinical development decisions.

"Major depressive disorder remains one of the most difficult conditions to treat, and too many patients have exhausted existing options without relief," said Dr. Gabriel Vargas, MD, PhD, Chief Clinical Advisor at Xylo Bio. "This Phase 1 study is designed to rigorously characterize XYL-1001's safety and pharmacology from the outset, giving us the foundation we need to move quickly and responsibly toward patients who need alternatives."

XYL-1001 is designed to be non-hallucinogenic and is, to the Company's knowledge, the most selective 5-HT2A receptor agonist in that category. The milestone marks the Company's transition to a clinical-stage organization. Xylo Bio is highlighting the program this week at the 9th Neuropsychiatric Drug Development Summit in Boston (Sept 15–17), where Dr. Samuel Banister, CSO and co-founder, is speaking.

"Dosing our first participants is a meaningful inflection point for Xylo Bio," said Dr. Banister. "Our mission is to unlock the therapeutic potential of the 5-HT2A receptor without the hallucinogenic burden and supervised dosing that limits who can access these treatments. This trial brings us one step closer to delivering on that mission."

About XYL-1001
XYL-1001 is, to the Company's knowledge, the most advanced selective 5-HT2A receptor agonist in clinical development today. The candidate is designed to activate the 5-HT2A receptor without producing hallucinogenic or other unwanted effects, an approach intended to retain therapeutic potential while avoiding the medical supervision and site-of-care requirements associated with psychedelic-based treatments. XYL-1001 has demonstrated 5-HT2A-dependent neuroplastic effects and efficacy in preclinical models of anxiety and depressive-like behaviors, without producing signs of hallucinogenic-related behavior. XYL-1001 is an investigational product and has not been approved by any regulatory authority for use.

About Major Depressive Disorder
Depressive disorders affect an estimated 332 million people worldwide, according to the World Health Organization, and remain among the leading causes of disability globally. Despite the availability of numerous approved antidepressants, up to one-third of patients fail to achieve adequate response after two or more treatment attempts, and existing therapies have delayed onset and undesirable side effects. This persistent treatment gap has driven a wave of drug development activity aimed at novel mechanisms of action, including rapid-acting and disease-modifying approaches, that can deliver faster, more durable relief with improved safety profiles for patients with inadequately treated depression.

About Xylo Bio
Xylo Bio (Psylo, Inc., doing business as Xylo Bio) is a clinical-stage biotechnology company advancing the next generation of neurotherapeutics to address significant unmet medical needs worldwide. Their mission is to transform lives with targeted neurotherapeutics. The company is building a pipeline of novel, non-hallucinogenic neuroplastogens engineered for oral delivery and scalable clinical utility. The company's compounds, developed with cutting-edge computational drug discovery, have demonstrated receptor selectivity, and promote neuroplasticity relevant to neuropsychiatric conditions while avoiding mechanisms linked to effects of psychedelics that restrict patient access.

For more information, visit www.xylo.bio

Contact:
Alaina Jaster
Head of Communications, Xylo Bio
alaina@xylo.bio
+1 (303) 219 1963