Safety of IPX066, an extended release carbidopa–levodopa formulation, for the treatment of Parkinson’s disease

Introduction: Levodopa (LD) is the most effective treatment for Parkinson’s disease (PD). However, chronic use of LD commonly results in the development of motor complications, including wearing off and dyskinesia. The presumption that the short serum half-life of LD is associated with the development of motor complications has raised the need to develop treatments with increased durations of stable LD concentrations. Areas covered: We conducted a PubMed search for IPX066 articles and also reviewed abstracts from meetings that included this topic. IPX066 is a newly developed formulation of extended release carbidopa–LD (CD–LD) with a one to four ratio of CD to LD, that was approved by the FDA in January 2015 for the treatment of PD, post-encephalitic parkinsonism, and parkinsonism that may follow carbon monoxide or manganese intoxication. It will be marketed by the trade name Rytary®. A Phase III clinical trial showed that IPX066 is efficacious in improving motor symptoms in early PD patients. In advanced PD patients with motor fluctuations, IPX066 reduced off time and increased on time without troublesome dyskinesia compared to CD–LD immediate release and CD–LD with entacapone. IPX066 had an acceptable safety profile. Adverse events of IPX066 from the different trials are presented. Expert opinion: IPX066 will probably have a role in the treatment of advanced PD with motor fluctuations. IPX066 could also be used initially when LD therapy is prescribed, but the question of whether this usage could reduce or prevent the development of motor complications is yet to be answered.