Idorsia Advances Daridorexant Into Autism Research After Phase 2 Trial Reveals Unexpected Functional Benefits in Switzerland

Allschwil-based Idorsia Ltd. (SIX: IDIA) will develop a dedicated program studying daridorexant in autism spectrum disorder, a move triggered by exploratory findings in children with ASD who took part in the company's pediatric insomnia trial.

The Swiss biopharmaceutical company said further details on the program, including doses to be studied, will follow in the first half of 2027 once discussions with global health authorities are complete.

What the Pediatric Trial Revealed

The company's randomized, placebo-controlled Phase 2 study enrolled 165 children and adolescents with insomnia disorder and measured objectively assessed total sleep time after single doses of daridorexant at 10, 25, and 50 mg. Results were presented at Sleep Europe 2026. More than half of the participants had a diagnosed or subthreshold neurodevelopmental disorder, including autism spectrum disorder or ADHD.

While sleep measures improved markedly, the 50 mg dose produced an unexpected pattern of improvement in affect and behavior, cognition, and daily activities among participants with ASD or subthreshold ASD characteristics, according to Idorsia.

A separate analysis presented at the Society for Developmental and Behavioral Pediatrics Annual Meeting focused on participants with ASD or subthreshold ASD from the dose-relationship study. A single 50 mg dose, the highest recommended dose in adults, consistently improved sleep parameters, including objective total sleep time, across participants with ASD, ADHD, or no neurodevelopmental disorder.

Using the PROMIS Pediatric Sleep-Related Impairment questionnaire, which assesses the impact of sleep problems on daytime functioning, researchers observed that after just two weeks of treatment at 50 mg, participants with ASD showed a distinct, consistent, and differentiated exploratory pattern of improvement across multiple facets of functioning compared with the overall population.

The effect was most noticeable on affect and behavior, cognition, and daily activities, facets Idorsia describes as highly relevant in ASD. The company noted that the uniform effect on sleep across all subpopulations, contrasted with the distinct pattern on functioning in the ASD group, may suggest the observed effect is not solely mediated by improved sleep but could extend to a treatment effect on autism spectrum disorder itself.

Executive and Expert Commentary

Chief Executive Officer Roland Wandeler said the company is intrigued by the observation from its clinical research, which he described as opening an entirely new scientific avenue for daridorexant and for Idorsia.

He emphasized the significance of investigating a potential new treatment approach for a condition where options remain extremely limited and said the opportunity shows the value of combining rigorous data analysis with deep scientific understanding to uncover new opportunities for patients and create long-term value.

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, said that for many children with ASD, difficulties with communication, social interaction, and everyday functioning can shape nearly every part of childhood and continue throughout life.

Families often carry that burden, she observed, while searching for therapeutic interventions that remain extremely limited. With no approved pharmacological treatment addressing the core features of ASD, she said a new treatment approach offers much-needed hope for children, caregivers, families, and clinicians.

Professor Emerita Judith Owens, MD, MPH, of the Department of Neurology at Harvard Medical School, called the initial sleep findings already exciting for clinicians treating children with insomnia, a highly underserved population.

Seeing a signal emerge early in children with ASD, beyond insomnia, is even more powerful, she said, adding that the findings deserve prospective evaluation in a dedicated clinical program to determine whether the signal can be confirmed and translated into meaningful benefit.

Biological Basis and Regulatory Path

Following the clinical observations, Idorsia said further investigation uncovered a biological rationale for orexin receptor antagonism in ASD. The company cited its in-house research data and published scientific research, together with the unique profile of daridorexant, as supporting the rationale for studying the drug in the condition.

The company's announcement indicated the line of investigation begins with the role of the orexin system in ASD, with detailed scientific evidence outlined in its accompanying release. In parallel with regulator discussions on program design, Idorsia is developing a dedicated formulation of the drug for the new indication.

Scale of the Unmet Need

Autism spectrum disorder is a lifelong neurodevelopmental disorder marked by persistent impairments in social communication and interaction and by restricted or repetitive behaviors, interests, or activities. Support needs vary widely, with some individuals requiring lifelong care.

Idorsia cited an estimated 61.8 million people affected worldwide and around 1 in 31 eight-year-old children in the United States. Both the company and its advisory board members highlighted the absence of any approved pharmacological treatment addressing the core features of the condition.

The announcement was made pursuant to Article 53 of the Listing Rules of the SIX Swiss Exchange and positions the ASD program as a development path distinct from daridorexant's established use in insomnia, with program details and doses to be disclosed in the first half of 2027.