Levodopa-carbidopa enteral suspension in advanced Parkinson's disease: clinical evidence and experience

The duration of action of oral levodopa becomes shorter as Parkinson's disease (PD) progresses. Patients with advanced PD may develop potentially disabling motor fluctuations and abnormal involuntary movement (dyskinesia), which cannot be managed with optimized oral or transdermal PD medications. The progressively worsening symptoms can have a substantial impact on the patient quality of life (QoL). Levodopa-carbidopa intestinal gel (LCIG) is delivered continuously via a percutaneous endoscopic gastrostomy with a jejunal extension (PEG-J). LCIG is licensed for the treatment of levodopa-responsive advanced PD in individuals experiencing severe motor fluctuations and dyskinesia when available combinations of antiparkinsonian medications have not given satisfactory results. Initial evidence for the efficacy and tolerability of LCIG came from a number of small-scale studies, but recently, three prospective studies have provided higher quality evidence. A 12-week double-blind comparison of LCIG with standard levodopa therapy, a 52-week open-label study extension of the double-blind study, and a 54-week open-label safety study, demonstrated significant improvements in 'off' time and 'on' time without troublesome dyskinesia, and QoL measures that were maintained in the longer term. There are also observations that LCIG may be effective treatment for nonmotor symptoms (NMS) although the evidence is limited. There is a need for further research on the efficacy of LCIG in reducing NMS, dyskinesia and improving QoL. This review surveys the clinical evidence for the effectiveness and tolerability of LCIG in the management of advanced PD and highlights some practical considerations to help optimize treatment.