Trigeminal neuralgia (TN), also called "tic douloureux", is the most common form of craniofacial neuropathic pain and is considered the cause of one of the most painful afflictions known in medical practice.

This study is designed to evaluate the efficacy and safety of 1.5mg - 3.5mg basimglurant in adults with TN.

This study is designed to evaluate the efficacy and safety of basimglurant (NOE-101) in patients with TN. Basimglurant is a potent inhibitor of metabotropic glutamate receptor 5 (mGluR5) which controls a wide range of processes in both central and peripheral nervous system. Inhibition of the mGluR5 receptor has shown therapeutic potential for pain associated with conditions such as TN. The drug has been shown to have a favorable safety profile in adults, children and adolescents. The aim of the study is to determine whether Basimglurant decreases both duration and intensity of facial pain associated with TN by use of a patient pain diary and the Patient-reported Global Impression of Change (PGI-C) compared to baseline.

Inclusion Criteria (Summary):

1. Ability and willingness to provide written informed consent and to comply with the study procedures.
2. Fluency in the language of the investigator, study staff and the informed consent.
3. Age 18-75 years.
4. Diagnosis of primary trigeminal neuralgia (TN) as per the ICHD-3 criteria confirmed by the study neurologist.
5. Experience pain due to TN and at baseline, experience at least 3 paroxysms per day of at least intensity of 4 or more on a pain intensity numerical rating scale (PI-NRS) during the last 7 days.
6. Female patients who are either sterile or menopausal. For female patients with childbearing potential, must be neither pregnant nor lactating (with appropriate contraceptive precautions and prior negative pregnancy tests).

Exclusion Criteria (Summary):

Patients who meet any of the following criteria will be excluded from participation in this study:

1. Current or prior history of any major psychiatric diagnoses unrelated to TN. Patients with TN-related depressive symptoms are permitted.

2. Current or prior history of mania, or psychotic episodes.

3. History of DSM-5-defined substance dependence and/or substance abuse in the last six months [180 days], except for nicotine.

4. Patient not willing to discontinue their current TN analgesic medication.

5. Use of opioids, except for pain control on a prn basis as long as it does not exceed 2 days per week.

6. Known allergic reaction to the investigational drug or one of its components.

7. Patients with secondary TN as per the ICHD-3 criteria.

   Medication history:

8. Previous treatment with basimglurant, except with the prior agreement of the medical monitor.

9. Treatment with antipsychotics within six months (180 days) of screening.

10. Any investigational drug within 90 days prior to initiation of study drug.

    Medical status:

11. Evidence of clinically significant, uncontrolled, unstable medical conditions or recently diagnosed cardiovascular disease, such as ischemic heart disease, coronary artery vasospasm, and cerebral ischemia. Subjects with myocardial infarction, acute coronary syndrome, percutaneous coronary intervention, cardiac surgery, stroke or transient ischemic attack during the 6 months prior to screening.

12. Subject has a history of gastric, or small intestinal surgery (including gastric bypass, gastric banding, gastric sleeve, gastric balloon, etc.) that may, in the opinion of the investigator, may cause malabsorption, or has a disease of the GI tract that causes malabsorption.

13. Body mass index > 39kg/m²

14. Patients with moderate or severely impaired hepatic function, ie, Pugh-Child score C.

15. Patients with severe renal impairment, ie, eGFR or creatinine clearance lower than 30mL/min.