The main objective of this study is to evaluate the efficacy, safety, and tolerability of NBI-827104 in adults with essential tremor.

Inclusion Criteria:

1. Male or female subjects, 18 to 75 years of age, inclusive at screening.
2. Body mass index (BMI) between 18 and 35 kg/m², inclusive, at screening.
3. Diagnosis of Essential Tremor (inclusive of Essential Tremor plus) as defined by the Movement Disorders Society Consensus Criteria for Tremor.
4. Confirmation of bilateral upper limb action tremor in the absence of overt dystonia, ataxia, or parkinsonism.
5. History of onset of tremor before 65 years of age.
6. Tremor Performance score of ≥ 2 on at least 2 of the 6 upper limb manoeuvres (Item 4) on the TETRAS Performance Subscale and a total TETRAS Performance score ≥15 at screening.
7. All women of childbearing potential and all males must practice effective contraception during the study and be willing and able to continue contraception for at least 90 days after their last dose of study drug.

Exclusion Criteria:

1. Evidence of any acute (at screening or prior to first dose) or chronic disease or condition that could interfere with, or for which the treatment might interfere with, the conduct of the study, or that would pose an unacceptable risk to the subject in the opinion of the investigator.
2. Have direct or indirect trauma to the nervous system within 3 months preceding the onset of tremor.
3. Have known history of other medical or neurological conditions that may cause or explain subject's tremor.
4. Have had prior magnetic resonance guided focused ultrasound or surgical intervention (e.g., deep brain stimulation, ablative thalamotomy or gamma knife thalamotomy).
5. Have a history or evidence of clinically significant cardiac conduction abnormality, uncontrolled bradyarrhythmia, heart failure, or long QT syndrome.