Objective: To estimate the potential cost-effectiveness of treating newly diagnosed glioblastoma patients with tumor treating fields (TTFields) and temozolomide (TMZ) based on data from the final analysis of the EF-14 Trial.

Background: Glioblastoma (GBM) is the most aggressive form of primary brain cancer in adults. The EF-14 Trial in GBM patients reported a 5-year survival rate of 13% for newly diagnosed GBM patients treated with TTFields and maintenance temozolomide (TMZ) chemotherapy. The cost-effectiveness of adding TTFields to the maintainance phase of the first line treatment protocol for GBM patients has not been previously assessed from a U.S. health system perspective.

Methods: The primary economic endpoint was the projected incremental cost-effectiveness ratio (ICER) for treatment of newly diagnosed GBM with TTFields and TMZ versus TMZ monotherapy alone during the maintenance phase of treatment. Patient outcomes were simulated using a 3-state area under the curve model including alive without progression, progressed disease, and death. Survival was modelled over a lifetime horizon by integrating the 5-year survival results reported in the EF-14 trial with long-term GBM epidemiology data and U.S. background mortality rates. Data on patient utilities used to calculate quality-adjusted life years (QALYs) were based on a previous analysis of GBM-specific health-state preferences. Costs and frequency of adverse events associated with TTFields and TMZ were estimated from the EF-14 trial. Supportive care cost estimates were derived from published literature. Future survival benefits and costs were discounted to present value at a rate of 3%. One-way and probabilistic sensitivity analyses were performed to assess result uncertainty due to parameter variability.

Results: Use of TTFields plus TMZ were projected to increase in undiscounted mean survival of 1.8 life years versus TMZ alone. The resulting life years gained (LYG) and quality-adjusted life years (QALYs) were 1.3 and 1.0, respectively, after discounting. The incremental total cost was $188,870. The ICER was$150,638 per LYG and $198,032 per QALY gained. The probability of TTFields being cost-effective was 70.5% at a willingness-to-pay threshold of$200,000 per QALY.

Conclusions: Treating newly diagnosed GBM patients with TTFields and TMZ has the potential to increase mean lifetime survival and quality-adjusted survival substantially compared to treatment with TMZ alone. TTFields therapy, even when evaluated at its full list price, demonstrated a high probability of cost-effectiveness at a willingness to pay threshold of \$200,000.

Citation Format: Gregory F. Guzauskas, Erqi L. Pollom, Volker W. Stieber, Bruce C. Wang, Lou Garrison. Tumor treating fields treatment for patients with newly diagnosed glioblastoma: A cost-effectiveness analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-257.