Allschwil, Switzerland-based Idorsia Ltd. (SIX: IDIA), has announced it will pursue a new development program for its drug daridorexant in autism spectrum disorder (ASD), a decision driven by unexpected improvements in affect, behavior, cognition, and daily activities observed among children with ASD in the company's Phase 2 pediatric insomnia study.

Program details are expected in the first half of 2027 following discussions with global health authorities.

An Unexpected Signal from a Pediatric Insomnia Study

The decision rests on findings from Idorsia's randomized, placebo-controlled Phase 2 study of daridorexant in 165 children and adolescents with insomnia disorder, which was recently presented at Sleep Europe 2026.

The study evaluated objectively measured total sleep time after one dose of daridorexant at 10, 25, and 50 mg. Notably, more than half of the participants had a diagnosed or subthreshold neurodevelopmental disorder, including ASD or attention-deficit/hyperactivity disorder (ADHD).

According to the company, in addition to marked improvements in sleep measures, daridorexant 50 mg showed an unexpected pattern of improvement in affect and behavior, cognition, and daily activities in participants with ASD or subthreshold ASD characteristics.

Idorsia stated that its in-house research data and published scientific research, together with the unique profile of daridorexant, further support the rationale for investigating the drug as a treatment for ASD.

The company is working on a dedicated formulation in parallel to discussions with health authorities about the design of the ASD development program, including the doses to be investigated. Further details will be shared in the first half of 2027.

Leadership Perspective on the New Avenue

Roland Wandeler, Chief Executive Officer of Idorsia, said the company is intrigued by an observation from its clinical research that opened an entirely new scientific avenue for daridorexant and for Idorsia itself.

He noted that the opportunity to investigate a potential new treatment approach for a condition where treatment options remain extremely limited gives the program particular significance.

Wandeler added that, beyond the potential impact for people living with ASD and their families, the opportunity demonstrates the value of combining rigorous analysis of the company's data with deep scientific understanding to uncover important new opportunities for patients and create long-term value for the company.

Details of the Exploratory Analysis

At the Society for Developmental and Behavioral Pediatrics Annual Meeting, Idorsia presented an analysis of data from participants with ASD or subthreshold ASD who were randomized in its dose-relationship study of daridorexant in children with insomnia disorder.

A single dose of daridorexant 50 mg, the highest recommended dose in adults, consistently improved sleep parameters, including objective total sleep time, in participants with ASD, ADHD, or no neurodevelopmental disorder.

The PROMIS Pediatric Sleep-Related Impairment questionnaire was used to assess the impact of sleep-related problems on daytime functioning. After only two weeks of treatment with daridorexant 50 mg, participants with ASD showed a distinct, consistent, and differentiated exploratory pattern of improvement across multiple facets of functioning compared to the overall population.

The magnitude of impact was particularly noticeable on affect and behavior, cognition, and daily activities, facets that the company describes as highly relevant to ASD.

Idorsia highlighted that the consistent effect on sleep parameters across all participant subpopulations, contrasted with the distinct exploratory pattern seen in participants with ASD on functioning, may suggest that the observed effect is not solely mediated by an improvement in sleep but could extend to a treatment effect on autism spectrum disorder itself.

Clinical Experts Weigh In

Professor Carmen Schröder, MD, PhD, of the Department of Child and Adolescent Psychiatry at Strasbourg University Hospitals and a member of Idorsia's Autism Advisory Board, commented that every child with autism spectrum disorder is different, but for many, difficulties with communication, social interaction, and everyday functioning can shape almost every part of childhood and continue throughout life.

She observed that families often carry that burden alongside them, providing extraordinary levels of practical and emotional support while searching for therapeutic interventions that remain extremely limited.

With no approved pharmacological treatment addressing the core features of ASD, she said, investigating a new treatment approach offers much-needed hope for children, their caregivers and families, and the clinicians who care for them.

Professor Emerita Judith Owens, MD, MPH, of the Department of Neurology at Harvard Medical School, said the initial findings on improved sleep were already exciting for clinicians caring for children with insomnia, a highly underserved population. To then see a signal emerge early on in children with ASD, beyond insomnia, is even more powerful, she stated.

According to Owens, the findings suggest that daridorexant could open a new avenue for patients with ASD and that these findings now deserve prospective evaluation in a dedicated clinical program to determine whether the signal can be confirmed and translated into a meaningful benefit for children with ASD and their families.

A Biological Rationale for Orexin Receptor Antagonism in ASD

Following the unexpected clinical findings, further investigation revealed a biological rationale for orexin receptor antagonism in ASD, according to the company.

Idorsia cited its in-house research data and published scientific research, as well as the unique profile of daridorexant, as further supporting the rationale for the investigation of the drug in the treatment of ASD.

The company's announcement indicated that this line of investigation begins with the role of the orexin system in ASD, though the detailed scientific evidence was outlined in the company's release accompanying the announcement.

The Burden of ASD and the Treatment Gap

Autism spectrum disorder is a lifelong neurodevelopmental disorder characterized by persistent impairments in social communication and interaction and by restricted or repetitive behaviors, interests, or activities.

Support needs vary widely, with some people requiring lifelong care. ASD affects an estimated 61.8 million people worldwide. In the United States alone, it affects around 1 in 31 eight-year-old children, according to the figures cited by Idorsia.

The absence of an approved pharmacological treatment addressing the core features of the condition, as noted by both the company and its advisory board members, underscores the significance the company attaches to the program.

Idorsia's announcement, made pursuant to Article 53 of the Listing Rules of the SIX Swiss Exchange, positions the ASD program as a distinct development path for daridorexant, separate from its established use as a treatment for insomnia, with the company committing to share further details on the program design and doses under investigation in the first half of 2027.

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