Carbidopa Levodopa Enteral Suspension Leads to Greater Cost-Effectiveness Over Standard Care

Rajesh Pahwa, MD

A recently published real-world study using an adapted Markov model showed that use of carbidopa levodopa enteral suspension (CLES) was associated with incremental costs and quality-adjusted life year (QALY) gain compared with standard of care (SoC) approaches among patients with Parkinson disease (PD). With an incremental cost-effectiveness ratio (ICER) of $7711/QALY, investigators concluded that CLES is a cost-effective option.

Led by Rajesh Pahwa, MD, professor of neurology, and director, Parkinson’s Disease and Movement Disorder Center, University of Kansas Medical Center, a previously published Markov model was adapted to the US healthcare setting with patient level data from an open-label clinical trial (NCT00335153) and an observational study (GLORIA). The model, comprised of 25 health states and a death state, represented the first cost-effectiveness model assessing CLES compared with SoC from a US payer perspective.

Patient data comprised of those with advanced PD and severe motor fluctuations, defined by scores of at least 3 on the Hoehn and Yahr scale and at least 4 hours of documented OFF time. SoC, the comparator used in the study, included conventional oral PD medications such as levodopa, second-generation dopamine agonists, Catechol-O-methyltransferase inhibitors, monoamine oxidase Type B inhibitors, and amantadine.

Using Clinical and Economic Review guidelines, discount rate was applied annually for both costs and effects (3.0%).As compared with SoC, CLES use was associated with an incremental cost of $6611, an incremental QALY gain of 0.86, and a LY incremental gain of 1.25 over a lifetime time horizon. While CLES was estimated to have higher drug acquisition and administration costs than SoC, it outperformed SoC in saving health care resource utilization costs of emergency room visits ($145,351) and hospitalizations ($65,414), professional caregiver ($49,217) and respite care ($9828).

READ MORE: Motor Evoked Potentials of Parkinson Disease Increased Through Accelerated Transcranial Ultrasound Neuromodulation, Pilot Study Shows

In a sensitivity analysis, CLES had a 92% probability of being cost-effective when a willingness-to-pay threshold was set to $100,000. Most cost-effectiveness pairs generated in the probabilistic sensitivity analysis were in the northeast quadrant, where CLES is associated with higher costs and greater QALY gain.

In a deterministic sensitivity analysis, assuming equal effectiveness for CLES and SoC after 5 years was associated with an ICER of $17,071/QALY. This figure decreased to $9580/QALY when assuming a gradual waning in the effectiveness of CLES after that time. Implementing efficacy data from the DUOGLOBE study between 25 and 36 months led to a QALY gain of 0.84 and a cost-savings of $7940 favoring CLES.

The assumption that patients derived no additional benefit from continued SoC treatment was considered a limitation; however, because the model included patients with advanced PD who had derived maximal clinical benefit from SoC, this was considered a reasonable assumption. Additionally, there were uncertainties in the model as a result of limited data, especially for severe health states, which were partially accounted for in the sensitivity analyses. Although different study datasets were used, the impact on the significance of the estimated parameters was not changed.

"The assumption that OFF-time progression benefits associated with CLES treatment observed in a clinical trial setting are sustained long-term is a potential source of uncertainty,” the study authors also noted. "However, many long-term studies have demonstrated improvements in OFF-time up to 3 to 5 years after baseline. Hence, the current assumption of a slower progression after the trial period, instead of a sustained benefit, may be considered conservative in the CEM."

REFERENCE
1. Pahwa R, Merola A, Soileau M, et al. Cost-effectiveness of cardbiopa-levodopa enteral suspension for advanced Parkinson’s disease in the United States. Mov Disord. Published October 25, 2023. doi:10.1002/mds.29624