Are Branded and Generic Extended-Release Ropinirole Formulations Equally Efficacious? A Rater-Blinded, Switch-Over, Multicenter Study

The aim of this study was to compare the efficacy of the branded and a generic extended-release ropinirole formulation in the treatment of advanced Parkinson's disease (PD). Of 22 enrolled patients 21 completed the study. A rater blinded to treatment evaluated Unified Parkinson's Disease Rating Scale, Fahn-Tolosa-Marin Tremor Rating Scale, Nonmotor Symptoms Assessment Scale, and a structured questionnaire on ropinirole side effects. Besides, the patients self-administered EQ-5D, Parkinson's Disease Sleep Scale (PDSS-2), and Beck Depression Inventories. Branded and generic ropinirole treatment achieved similar scores on all tests measuring severity of motor symptoms (primary endpoint, UPDRS-III: 27.0 versus 28.0 points, P = 0.505). Based on patient diaries, the lengths of “good time periods” were comparable (10.5 and 10.0 hours for branded and generic ropinirole, resp., P = 0.670). However, generic ropinirole therapy achieved almost 3.0 hours shorter on time without dyskinesia (6.5 versus. 9.5 hours, P < 0.05) and 2.5 hours longer on time with slight dyskinesia (3.5 versus. 1.0 hours, P < 0.05) than the branded ropinirole did. Except for gastrointestinal problems, nonmotor symptoms were similarly controlled. Patients did not prefer either formulation. Although this study has to be interpreted with limitations, it demonstrated that both generic and branded ropinirole administration can achieve similar control on most symptoms of PD.