Cost-effectiveness of extended-release carbidopa-levodopa for advanced Parkinson’s disease

Objectives: Prolonged treatment of Parkinson’s disease (PD) with immediate-release (IR) carbidopa-levodopa (CD-LD) often leads to motor fluctuations, including dyskinesia and reemergence of PD symptoms (“off” time). Adding entacapone (E) to IR CD-LD (to create CL+E) improved efficacy; however, recent clinical studies demonstrated improved efficacy with extended-release carbidopa-levodopa (IPX066) compared with CL+E. This study evaluated the long-term cost-effectiveness of IPX066 versus branded and generic CL+E from the US payer perspective. Study Design: State-transition Markov analysis. Methods: A Markov model (6-month cycle, 3% annual discount rate) was developed to simulate PD progression over 5 years through 3 health states: ≤25% “off” time, >25% “off” time, and death. Dosing and efficacy data were from a phase 3 study comparing IPX066 with CL+E (administered either as IR CD-LD [Sinemet 25/100 mg] + entacapone [Comtan 200 mg] or CL+E combination tablet [branded]) and an open-label extension study. Health state utilities were from published literature. Total direct costs and quality-adjusted life-years (QALYs) were evaluated. One-way sensitivity analyses evaluated input uncertainty ranges and identified inputs that most affected the results. Results: Total 5-year costs with IPX066, branded CL+E, and generic CL+E therapy were $68,703, $91,949, and $79,332, respectively. Intervention-related costs for IPX066 treatment were less than those for branded CL+E and slightly more than those for generic CL+E. The analysis showed cost savings with IPX066 of $166,044 per QALY gained, compared against branded CL+E, and $75,920 per QALY gained against generic CL+E. One-way sensitivity analyses demonstrated dominance with IPX066 in the majority of scenarios. Conclusions: IPX066 was cost-effective compared with both branded and generic CL+E and was expected to lower total 5-year costs and increase QALYs for patients with PD.