This study is testing a new drug called IPN10200 to see if it helps adults with Cervical Dystonia (CD). CD is a condition that causes neck pain, stiffness, and headaches. The usual treatment uses BoNT injections, but they only last about 3 months. IPN10200 is designed to last longer.

The study has two parts:

1. A Screening Period of up to 4 weeks to check if you can join.
2. A Treatment Period lasting 36 weeks.

On the first day, you'll get either the study drug or a placebo (a fake treatment) in your neck, head, and shoulders. You can still take some other medicines, but keep track of them.

You'll visit the clinic 10 times, plus one phone call. If you're in a special group, you'll visit 12 times. During visits, there will be tests like blood samples, urine tests, physical checks, and you’ll fill out questionnaires. The whole study lasts about 9 months.

• Duration: Up to 40 weeks.
• Visits: 10-12 visits to the clinic, plus one phone visit.
• Tests: Includes blood, urine, and physical exams.