2616 - Cost-Effectiveness of Vorasidenib for Patients with Isocitrate Dehydrogenase (IDH) Mutated Low-Grade Glioma (LGG)
Presenter(s)
A. C. Kessel1, H. Kim2, P. D. Brown3, E. J. Lehrer1, N. N. Laack II1, A. Mahajan1, E. S. Yan1, S. Kizilbash4, B. J. Neth5, U. Sener5, M. R. Waddle1, W. Breen1, and R. O. Kowalchuk1; 1Department of Radiation Oncology, Mayo Clinic, Rochester, MN, 2Department of Radiation Oncology, UPMC Hillman Cancer Center, Pittsburgh, PA, 3Mayo Clinic Cancer Center, Rochester, MN, 4Department of Medical Oncology, Mayo Clinic, Rochester, MN, 5Department of Neurology, Mayo Clinic, Rochester, MN
Purpose/Objective(s): The INDIGO clinical trial demonstrated a benefit in progression-free survival with vorasidenib compared to a placebo for IDH-mutated LGG. However, it is unclear how this treatment’s impact on overall survival (OS), quality of life, and cost compares to standard treatment: observation or chemoradiation (CRT). We hypothesize that at vorasidenib’s current cost, it may not meet standard thresholds to be a cost-effective treatment for IDH mutated LGG.
Materials/Methods: We evaluated the cost-effectiveness of vorasidenib, CRT, and observation for patients with IDH mutated LGGs using a decision tree with an integrated Markov model. We used data from EORTC 22845 and RTOG 9802 to select model parameters and allowed for general tolerances in established data. Patients could exist in one of three states: stable disease, progressive disease, or death. Costs were measured from a healthcare system perspective, including drug cost, grade 3+ toxicity burden, and management of disease progression. Utility values were assigned based on health states. Outcomes were expressed as incremental cost-effectiveness ratios (ICERs) per quality-adjusted life-year (QALY) gained. Treatment is considered cost effective if it meets the commonly accepted willingness-to-pay threshold of $100,000 per QALY gained.
Results: Per the Veteran Affairs Federal Supply Schedule, vorasidenib costs $30,048 for a 30-day supply. Based on a 5-year model, vorasidenib demonstrated an ICER of $744,195 per QALY when compared to CRT. When compared to observation, vorasidenib demonstrated an improved ICER of $208,370 per QALY. On one way sensitivity analysis compared to observation, median cost of vorasidenib and median OS were most likely to affect ICER with only marginal changes on analysis of other model factors. For ICER to become < $100,000 compared to observation, the cost of vorasidenib would need to drop to below $11,465 monthly, or the median OS ratio benefit would need to improve to < 0.42.
Conclusion: Using the best available data, the current price of vorasidenib reduces its ability to meet commonly accepted cost-effectiveness thresholds in treatment of IDH-mutated LGGs. This model suggests that to make vorasidenib cost-effective by standard definitions, a cost reduction of vorasidenib is required, or further prospective research must show an OS benefit. Our model is limited by the inherent lack of a directly comparable treatment population representing real-world patients with IDH-mutated LGGs treated with vorasidenib; however, the model was robust to sensitivity analyses of most model parameters, suggesting a reproducible result. We await long term results along with consideration of therapy combinations which may make vorasidenib cost effective.