A Study to Investigate the Efficacy and Safety of NT 201 (Botulinum Toxin) Compared With Placebo for the Treatment of Adult Participants With Essential Tremor in the Arm

The purpose of this study is to determine whether a single treatment with NT 201 (botulinum toxin) is superior to placebo (no medicine) for one-sided treatment of essential tremor in the motor-dominant arm (Unilateral Period). Participants will be assigned to the treatment groups by chance and neither the participants nor the research staff who interact with them will know the allocation. The following treatment cycle will investigate the safety and tolerability of two-sided treatment with NT 201 (botulinum toxin) (Open Label Bilateral Period). All participants will receive NT 201 treatment.

Inclusion Criteria: \- Score of ≥ 2 (at least 1 cm tremor amplitude) in at least two out of three maneuvers of test item 4 (upper limb tremor) of the TETRAS performances scale confirmed by an independent TETRAS expert by means of video assessment. Exclusion Criteria: * History or presence of day-to-day fluctuations in ET which would jeopardize meaningful tremor assessment over time, e.g. severe tremor on one day and minimal or no tremor on another day. * Other neurological signs, such as dystonia, ataxia, or parkinsonism, which in the judgment of the investigator could interfere with the ET diagnosis and/or assessment of ET in ULs. * Tremor types other than ET