Recent analysis of Phase II balovaptan data in paediatric ASD did not support the continuation of this study. No new safety concerns were identified.

This was a Phase Ib, multicenter, open-label study in children 2-4 years old with autism spectrum disorder (ASD) to investigate the pharmacokinetics, safety, and tolerability of an oral dose of balovaptan once a day (QD). The study was to consists of a 6-week treatment period to evaluate the pharmacokinetics of balovaptan in 2 to 4 year old children followed by an optional extension period of 48 weeks.

Inclusion Criteria:

• Diagnosis of ASD according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for ASD. Diagnostics will be performed by a team of autism experts and confirmed by Autism Diagnostic Observation ScheduleTM, Second Edition (ADOS-2) criteria. The DSM-5 criteria for diagnosis of autism must be met with the highest confidence in the opinion of the investigator. Children with ambiguous diagnostic results cannot be enrolled in the study. If the ADOS-2 assessment has been performed by a certified rater and documented within 12 months of the screening visit, it is not mandatory to repeat it unless the subject was assessed below an age of 2 years.
• Hearing and vision compatible with the study assessments, as judged by the investigator
• Ability for subject and the caregiver to comply with the study protocol, in the investigator's judgment
• Availability of a parent or other reliable caregiver who is fluent in language of the site and has frequent and sufficient contact with the subject.

Exclusion Criteria:

• Clinically significant psychiatric and/or neurologic comorbidity that may interfere with the safety or efficacy endpoints in the view of the investigator
• Clinically significant regression of any acquired language and motor function skills in the opinion of the investigator throughout the subject's development
• History of seizures with the exception of a single, non-complicated febrile seizure >= 6 months before screening
• Clinical diagnosis of peripheral neuropathy or signs and symptoms indicative of peripheral neuropathy
• Any clinically relevant cardiovascular disease
• Confirmed elevation in cardiac troponin I (cTn I), high-sensitive cardiac troponin T (hs cTn T), N-terminal pro-B-type natriuretic peptide (NT-proBNP) or, if conducted, clinically relevant abnormality in Doppler echocardiogram
• Confirmed clinically significant abnormality on ECG at screening, including, but not limited to, a QT interval corrected through use of Fridericia's formula (QTcF) of >= 450 ms, absence of dominating sinus rhythm, or second- or third-degree atrioventricular block
• Confirmed systolic or diastolic blood pressure above the 95th percentile or below the 5th percentile according to the Centers for Disease Control and Prevention (CDC) norm tables referring to stature (height)-for-age percentiles
• Confirmed heart rate: >150 bpm in 2-year old children, >135 bpm in 3-year old children, or >120 bpm in 4-year old children.
• Concomitant disease or condition that could interfere with, or treatment of which might interfere with, the conduct of the study; or discontinuation of prohibited medication that might pose unacceptable risks to the subject in the opinion of the investigator
• Evidence for current GI disease that would interfere with the conduct of the study or pose unacceptable risks in the opinion of the investigator
• History of coagulopathies, bleeding disorders, or blood dyscrasias
• Positive serology for HIV-1 or HIV-2
• Confirmed clinically significant abnormality in parameters of hematology, clinical chemistry, coagulation, or urinalysis, specifically a confirmed absolute neutrophil count (ANC) \

Qualified researchers may request access to individual patient level data through the clinical study data request platform (www.clinicalstudydatarequest.com). Further details on Roche's criteria for eligible studies are available here (https://clinicalstudydatarequest.com/Study-Sponsors/Study-Sponsors-Roche.aspx). For further details on Roche's Global Policy on Sharing of Clinical Study Information and how to request access to related clinical study documents, see here (https://www.roche.com/research\_and\_development/who\_we\_are\_how\_we\_work/clinical\_trials/our\_commitment\_to\_data\_sharing.htm).

The Study being conducted under this Agreement is part of the Overall Study. Investigator is free to publish in reputable journals or to present at professional conferences the results of the Study, but only after the first publication or presentation that involves the Overall Study. The Sponsor may request that Confidential Information be deleted and/or the publication be postponed in order to protect the Sponsor's intellectual property rights.