ABBV-951 is a new soluble formulation of carbidopa and levodopa prodrugs, delivered as a CSCI via an external pump, being developed for the treatment of PD. Previous Ph1 studies demonstrated that ABBV-951 was well-tolerated in healthy volunteers. Here we assessed the safety of individually titrated therapeutic doses of ABBV-951 administered to PD patients via 24-hour CSCI for 28 days in an outpatient setting.

Twenty-one patients were included in the safety analysis(62% male, mean age 61.6, 43% with ≥10 years PD duration). AEs occurred in 19 patients(90.5%); 2 serious AEs (cellulitis and abdominal abscess) were reported in 1 patient who prematurely discontinued the study. Another patient prematurely discontinued due to an AE of infusion site infection. Five patients(24%) had Numeric Score ≥3 or Letter Grade ≥C on the Infusion Site Evaluation Scale; all other patients were classified as 0, 1, or 2 score or A or B grade, consistent with findings reported for other CSCI therapies. There were no clinically significant changes in laboratory, ECG, or vital sign parameters. ABBV-951 doses ranged 400mg-3400mg levodopa equivalents. Exploratory efficacy results showed decreased “Off” time compared to baseline.