Inclusion Criteria:  Qualified for and had their initial dose of study drug in the ABP-19000 or ABP-19001 studies and for whom 8 weeks have elapsed between last treatment in the double-blind study (ie, EOS visit) and first treatment in the ABP-19002 OLE study. Provided written informed consent to being treated for cervical dystonia with ABP-450. Were a male or female patient between 18 and 75 years of age (inclusive) when they entered the ABP-19000 or ABP-19001 studies. Have clinical diagnosis of cervical dystonia and need for injection, as determined by the investigator, with TWSTRS total score ≥20. Entered the ABP-19000 or ABP-19001 study on a stable dose of medications (if any) used for focal dystonia treatment (eg, anticholinergics and benzodiazepines) for ≥3months prior to and expected throughout the duration of the study. Stated willingness to comply with all study procedures, including attendance at the study center for all study visits as scheduled and have technological capabilities to have tele visits.  Exclusion Criteria:  Have traumatic torticollis or tardive torticollis. Have predominant retrocollis or anterocollis. Have hypersensitivity to human serum albumin, sucrose, or botulinum toxin type A. Have diagnosis of myasthenia gravis, Lambert-Eaton syndrome, amyotrophic lateral sclerosis, or any other significant neuromuscular disease that might interfere with the study. Have marked limitation on passive range of motion that suggests contractures or other structural abnormality (eg, cervical contractures or cervical spine syndrome). Have medical or psychiatric conditions that may increase the risk associated with study participation or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the patient inappropriate for entry into this study. Current swallowing disorder of any origin (dysphagia scale ≥3, ie, severe, with swallowing difficulties and requiring a change in diet). Participated in another interventional study during participation in this study. Were a pregnant or lactating female, or female of child-bearing potential not willing to use an acceptable method of contraception (ie, intrauterine device, barrier methods with spermicide, or abstinence). Would not benefit from treatment with ABP-450 for their cervical dystonia, in the investigator's opinion. Viral or other active infection or any medical condition that, in the opinion of the investigator, classifies the patient as unsuitable for participation in the study or patients who do not seem to be in good general health at the time of Day 0 "rollover", and prior to any investigational study drug administration.