Long-term follow-up study to evaluate the safety of clonidine micropellets up to 12 months post injection.

Inclusion Criteria:

• Subject who have successfully completed all STX-015-18-01 study related activities, are reconfirmed to be eligible and have signed informed consent to participate.

Exclusion Criteria:

• Subjects who, in the opinion of the investigator, have demonstrated significant non-compliance with STX-015-18-01 study procedures.
• Subjects who were unblinded to their treatment in STX-015-18-01 study.

Comprised of the first 100 subjects who completed all STX-015-18-01 study-related activities, age 18-70, male/female, reconfirmed eligible and signed informed consent.