Conversion to carbidopa and levodopa extended-release (IPX066) followed by its extended use in patients previously taking controlled-release carbidopa-levodopa for advanced Parkinson's disease

Abstract Background IPX066 (Rytary®; carbidopa and levodopa [CD-LD] extended-release capsules) was designed to achieve therapeutic LD plasma concentrations within 1 h of dosing and maintain LD concentrations for a prolonged duration in early or advanced Parkinson's disease (PD). Methods In this open-label study, patients underwent 6 weeks of conversion to IPX066 from their prior controlled-release (CR) ± immediate-release (IR) CD-LD therapy and 6 months of maintenance (with an additional 6 months of IPX066 at some sites). Clinical utility was assessed at both the end of conversion and maintenance. Results Among 43 patients initiated on IPX066, 33 completed conversion. The mean LD conversion ratio was 1.8 among 30 patients previously on CR plus IR (and 1.5 among 3 previously taking CR alone). The mean IPX066 dosing frequency was 3.5 times/day compared with 2.6 times/day for CR plus 4.6 times/day for IR previously (and 4.7 times/day for CR alone). By patient and clinician global improvement ratings after 6-month maintenance, ≥ 43.8% of patients were much or very much improved from their previous treatment, and ≥ 68.8% were at least minimally improved. Adverse events were consistent with those reported in prior IPX066 studies. Conclusions These results suggest that advanced PD patients using CR CD-LD ± IR can be safely converted to IPX066, with high likelihood of achieving a stable regimen, less frequent LD dosing, and improved overall clinical benefit. Trial registration: Clinicaltrials.gov NCT01411137 .