This Open-label Extension trial will evaluate the safety and efficacy of ABP-450 for the treatment of cervical dystonia in adults. The study will enroll 60 patients across approximately 42 sites in the United States from Phase 2 (ABP-19000) trial. Study subjects who had their initial dose of study drug in the Phase 2 trial, irrespective of treatment allocation, will be eligible to enroll in this OLE study. Study subjects will receive a predetermined dose of ABP-450 between the Low Dose and High Dose, based on the investigator's discretion and clinical judgment.
