One early therapy study was a 12-week multicenter study in which 63 patients (41 on ropinirole hydrochloride) with idiopathic Parkinson’s disease receiving concomitant anti-Parkinson medication (but not L-dopa) were randomized to either ropinirole hydrochloride or placebo. Patients had a mean disease duration of approximately 2 years. Patients were eligible for enrollment if they presented with bradykinesia and at least tremor, rigidity, or postural instability. In addition, they must have been classified as Hoehn & Yahr Stage I-IV. This scale, ranging from I = unilateral involvement with minimal impairment to V = confined to wheelchair or bed, is a standard instrument used for staging patients with Parkinson’s disease. The primary outcome measure in this trial was the proportion of patients experiencing a decrease (compared to baseline) of at least 30% in the UPDRS motor score.

Patients were titrated for up to 10 weeks, starting at 0.5 mg twice daily, with weekly increments of 0.5 mg twice daily to a maximum of 5 mg twice daily. Once patients reached their maximally tolerated dose (or 5 mg twice daily), they were maintained on that dose through 12 weeks. The mean dose achieved by patients at study endpoint was 7.4 mg/day. At the end of 12 weeks, 71% of patients treated with ropinirole hydrochloride were responders, compared with 41% of patients in the placebo group (p = 0.021).

Statistically significant differences between the percentage of responders on ropinirole hydrochloride compared to placebo were seen after 8 weeks of treatment. 

In addition, the mean percentage improvement from baseline in the Total Motor Score was 43% in patients treated with ropinirole hydrochloride compared with 21% in patients treated with placebo (p = 0.018).

Statistically significant differences in UPDRS motor score between ropinirole hydrochloride and placebo were seen after 2 weeks of treatment. 

The median daily dose at which a 30% reduction in UPDRS motor score was sustained was 4 mg.

The second trial in early Parkinson’s disease (without L-dopa) patients was a double-blind, randomized, placebo-controlled, 6-month study. Patients were essentially similar to those in the study described above; concomitant use of selegiline was allowed, but patients were not permitted to use anticholinergics or amantadine during the study. Patients had a mean disease duration of 2 years and limited (not more than a 6-week period) or no prior exposure to L-dopa. The starting dose of ropinirole hydrochloride in this trial was 0.25 mg 3 times daily. The dose was titrated at weekly intervals by increments of 0.25 mg 3 times daily to a dose of 1 mg 3 times daily. Further titrations at weekly intervals were at increments of 0.5 mg 3 times daily up to a dose of 3 mg 3 times daily, and then weekly at increments of 1 mg 3 times daily. Patients were to be titrated to a dose of at least 1.5 mg 3 times daily and then to their maximally tolerated dose, up to a maximum of 8 mg 3 times daily. The mean dose attained in patients at study endpoint was 15.7 mg/day.

The primary measure of effectiveness was the mean percent reduction (improvement) from baseline in the UPDRS Motor Score. In this study 241 patients were enrolled. At the end of the 6-month study, patients treated with ropinirole hydrochloride had 22% improvement in motor score, compared with a 4% worsening in the placebo group (p<0.001).

Statistically significant differences in UPDRS motor score improvement between ropinirole hydrochloride and placebo were seen after 12 weeks of treatment.