A Study to Assess the Safety, Tolerability and Pharmacokinetics of XEP527 in Patients With Stable Schizophrenia

Key Inclusion Criteria:

* Signed informed consent must be obtained prior to participation in the study
* Participants 18 to 65 years of age, inclusive at screening
* Participant agrees to be hospitalized starting at Day -1 and for at least 28 days after randomization
* Participant has a primary diagnosis of schizophrenia established by a comprehensive psychiatric evaluation based on the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) criteria and confirmed by Mini International Neuropsychiatric Interview for Schizophrenia and Psychotic Disorder Studies (MINI), version 7.0.2. at screening
* Participant meets the following requirements per PANSS at screening and baseline: Total PANSS score ≤ 110, Score ≤ 4 (moderate) for item P1-P7, Score ≤ 4 (moderate) for G9
* Participant is treated with a single antipsychotic (typical and/or atypical) with a stable dose for at least 12 weeks prior to randomization. Participant must agree to maintain the treatment with standard of care antipsychotic for the duration of the study
* Participants who are treated with psychotropic medications other than antipsychotics need to be taking these medications as a stable dose for at least 12 weeks before randomization

Key Exclusion Criteria:

* Participant experienced worsening of schizophrenia within 3 months prior to randomization documented by symptom exacerbation and/or hospitalizations (hospitalization for social management and/or day hospital programs within this time are acceptable)
* Participant was treated with Clozapine, electroconvulsive therapy (ECT) or transcranial magnetic stimulation (TMS) in the last 6 months prior to randomization
* Participant meets the DSM-5 criteria for another psychotic disorder
* Participant has a history of substance or alcohol use disorder, except nicotine or caffeine, within 1 year before screening, or current abuse as determined by urine drug screen or alcohol test
* Score "yes" on item 4 or item 5 of the Suicidal Ideation section of the C-SSRS, if this ideation occurred in the past 6 months, or "yes" on any item of the Suicidal Behavior section, except for the "Non-Suicidal Self-Injurious Behavior" (item also included in the Suicidal Behavior section), if this behavior occurred in the past 2 years.

Other protocol-defined inclusion/exclusion criteria may apply.