AN ECONOMIC ANALYSIS OF THE ADDITION OF BEVACIZUMAB TO STANDARD CHEMOTHERAPY IN PATIENTS WITH MALIGNANT PLEURAL MESOTHELIOMA

Thesis (Master's)--University of Washington, 2016-08

Objectives A recent Phase III trial, MAPS (Mesothelioma Avastin Cisplatin Pemetrexed Study), investigated the addition of bevacizumab to cisplatin plus pemetrexed (PCB) as compared to pemetrexed plus cisplatin (PC) alone in malignant pleural mesothelioma (MPM) patients. The trial results indicate that patients taking bevacizumab had improved progression free survival (PFS) and overall survival (OS) compared with the control group. Our objective was to evaluate the cost-effectiveness of adding bevacizumab to cisplatin and pemetrexed from a Medicare perspective. Methods A partition-survival model with 3 health states: Pre-progressive, Progressive and Death, was developed to perform the cost-utility analysis. Survival data were derived from the MAPS study. We used the method described by Hoyle & Henley to derive appropriate parametric survival functions for the PFS and OS curves, using Kaplan-Meier curves extrapolated to lifetime as the base case. The treatment of adverse events (grade 3+ and with frequencies of at least 5% in one of the arms) were included in the evaluation. Utility data were derived from the literature on patient quality of life in non-small cell lung cancer. Costs included treatment, administration, adverse events, and supportive care and were calculated based on average sales price, diagnosis-related group payments, current procedural terminology codes and publications in the literature. The model used monthly cycles, a 3% discount rate and costs were reported in 2015 US$. One-way, scenarios and probabilistic sensitivity analyses (PSA) to evaluate the impact of parameter uncertainty were undertaken. A value of information analysis was performed to determine the value of perfect information and value of perfect parameter information. Results Compared to standard chemotherapy, patients receiving bevacizumab plus pemetrexed and cisplatin had 0.285 more life years (LYs), 0.20 more quality adjusted life years (QALYs), and an additional cost of $146,851 per individual. The incremental cost effectiveness ratios (ICER) were estimated to be $515,850 per life year gained and $726,110 per QALY gained. A one-way sensitivity analysis showed that the parameters with the most impact on the results were the survival distributions, pre-progressive utility scores and bevacizumab drug cost. The PSA indicated that PCB has a 0% probability of being cost effective at a Willingness-To-Pay threshold of $ 150,000 per QALY gained. Conclusion The addition of bevacizumab to the current standard of care may not be considered cost-effective from a Medicare perspective according to commonly used willingness-to-pay thresholds.