This study is designed to evaluate the efficacy and safety of gemlapodect (NOE-105) on reducing tics associated with Tourette Syndrome (TS) in adults with TS. Adolescents will be enrolled after a sentinel cohort of adults is complete.

Gemlapodect is an investigational selective PDE10A inhibitor with a potential therapeutic effect for the treatment of tics associated with Tourette Syndrome (TS). This is a multi-center, double-blind, parallel-arm, placebo-controlled study in patients with TS. Following screening to confirm eligibility and to wash-out previous TS medication during a 14-day placebo run-in, patients will be randomized 1:1 on Day 1 to receive gemlapodect or placebo once daily for 12 weeks. See https://allevia2study.com

Inclusion Criteria:

1. Initially, patients aged 18 years onwards, at the time of signing the ICF form. Adolescents aged 12 years and older at the time of signing the ICF/informed assent form will be eligible for inclusion after completion of a sentinel cohort of adults.
2. Moderate to severe Tourette Syndrome as defined by DSM-5 diagnostic criteria and TS-CGI-S ≥ 4.
3. Treatment naive or previously treated patients in need of treatment alternative as per investigators judgement.
4. Patients must discontinue all medications used to treat TS for at least 14 days prior to randomization. Other psychotropic drugs, including stimulants, will be allowed provided they have been stable for at least 30 days prior to randomization and are expected to remain stable for the duration of the study.
5. BMI within the range 18 to 35 kg/m2 (inclusive).
6. Women of childbearing potential should only be included after a confirmed menstrual period and a negative highly sensitive urine or serum pregnancy test. Contraceptive use should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies.
7. Capable of giving signed informed consent or consent from their legal representative.
8. Fluency in the language of the investigator, study staff, and the ICF/informed assent form when applicable.

Exclusion Criteria:

1. Any medical condition which, in the opinion of the investigator, could interfere with study procedures including but not limited to functional tic-like disorder, secondary tic symptoms accompanied by late-onset tics, Huntington's chorea, malignant TS, neuroacanthocytosis, autism, and history of known intellectual disability that would affect patient's ability to comply with study procedures.
2. Current active diagnosis of severe anxiety, bipolar disorder, schizophrenia, major depressive disorder (MDD,), or Parkinson's disease. Patients with a history of MDD on selective serotonin reuptake inhibitors treatment stable for at least a month may participate in the study.
3. A history of severe traumatic brain injury or stroke.
4. Any unstable medical conditions, severe symptoms, or clinically significant abnormalities on screening test/examinations, including uncontrolled seizure disorders, which, in the investigator's judgment, will put them at a risk of major AE during this trial, or will interfere with safety and efficacy assessments.
5. Are undergoing active CBT (including but not limited to comprehensive behavioral intervention for tics, exposure and response prevention, relaxation training) during the last 28 days before the planned date of randomization and until the end of the trial. Patients willing to discontinue their CBT over this period are eligible to enroll in the study.
6. Known DSM-5 diagnosis of substance abuse or dependence.
7. Active suicidal ideation or behavior.
8. Use of prescribed or recreational cannabinoids during the study are prohibited. Prescribed cannabinoids include Epidiolex® (cannabidiol), Marinol® /Syndros® (dronabinol), and Cesamet® (nabilone). These medications will be discontinued during the Screening period. Study participants prescribed cannabinoids for seizure disorders are not eligible for study participation. Recreational cannabinoids, regardless of their form of intake, which include tetrahydrocannabinol and/or cannabidiol, are prohibited.
9. Strong inhibitors and inducers of CYP3A4 are prohibited during the study.
10. Neurostimulation/deep brain stimulation for TS.
11. Participation in another clinical study with a study intervention administered in the last 30 days.
12. Patients with a known hypersensitivity to gemlapodect or any of the excipients of the product
13. Positive urine drug screen for cannabis, cocaine, or nonprescribed opiates.
14. The person is an employee or family member of an employee of the Sponsor, Investigator, or study site personnel.
15. Judgment by the investigator that the patient should not participate in the study if the patient is unlikely to comply with study procedures, restrictions, and requirements.
16. Previous randomization in the present study.
17. The person is currently committed to an institution by virtue of an order issued either by the judicial or the administrative authorities