Estimating Life-Years and QALYs Gained From Tumor Treating Fields in Newly Diagnosed Glioblastoma: A US-Based Real-World Survival-Based Model
Author(s)
Jorge F. Nino de Rivera Guzman, MSc1, Gordon Vincent Chavez, BA2, Patrick Conlon, MD3, Bruce Wang, PhD4, Jennifer M. Connelly, MD5.
1Health Economy specialist, Novocure, Glendale, CO, USA, 2Novocure, New York, NY, USA, 3Novocure, Portsmouth, NH, USA, 4Elysia Group, LLC, New York, NY, USA, 5Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA.
1Health Economy specialist, Novocure, Glendale, CO, USA, 2Novocure, New York, NY, USA, 3Novocure, Portsmouth, NH, USA, 4Elysia Group, LLC, New York, NY, USA, 5Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA.
OBJECTIVES: Estimate the life-years (LYs) and quality-adjusted life-years (QALYs) gained with Tumor Treating Fields (TTFields) plus temozolomide (TMZ) versus standard of care (SoC) alone in newly diagnosed glioblastoma (ndGBM), leveraging 8-year U.S. real-world survival data.
METHODS: Overall survival (OS) and progression-free survival (PFS) were sourced from an independent real-world study conducted at the Medical College of Wisconsin, which followed ndGBM patients treated with TTFields + TMZ or SoC for up to 8 years. Kaplan-Meier curves were used directly through year 8, extending the 5-year extrapolation used in previously published models. Conditional probabilities informed survival projections for years 8-15, followed by U.S. life tables beyond year 15. LYs were calculated as the area under the OS curve. QALYs were estimated by applying utility weights derived from prior published literature.
RESULTS: The study included 208 patients (109 in the TTFields + TMZ arm and 99 in the SoC arm), with comparable baseline characteristics between groups. Treatment with TTFields + TMZ resulted in a gain of 1.39 life-years versus SoC (5.05 vs. 3.65 LYs). The corresponding QALY gain was 1.05 (3.86 vs. 2.81 QALYs). These real-world survival and QALY gains are consistent with the results of using the data from the EF-14 trial, which demonstrated a 1.25 life-years and 0.96 QALYs gain for TTFields + TMZ versus TMZ alone.
CONCLUSIONS: Using 8-year real-world survival data improves the accuracy of long-term outcome estimates while reducing reliance on extrapolation assumptions. The observed life-year and QALY gains with TTFields + TMZ in routine clinical practice reinforce its clinical value and support continued use in ndGBM. These findings serve as a foundation for future health economic evaluations, including cost-effectiveness analyses based on real-world data.
METHODS: Overall survival (OS) and progression-free survival (PFS) were sourced from an independent real-world study conducted at the Medical College of Wisconsin, which followed ndGBM patients treated with TTFields + TMZ or SoC for up to 8 years. Kaplan-Meier curves were used directly through year 8, extending the 5-year extrapolation used in previously published models. Conditional probabilities informed survival projections for years 8-15, followed by U.S. life tables beyond year 15. LYs were calculated as the area under the OS curve. QALYs were estimated by applying utility weights derived from prior published literature.
RESULTS: The study included 208 patients (109 in the TTFields + TMZ arm and 99 in the SoC arm), with comparable baseline characteristics between groups. Treatment with TTFields + TMZ resulted in a gain of 1.39 life-years versus SoC (5.05 vs. 3.65 LYs). The corresponding QALY gain was 1.05 (3.86 vs. 2.81 QALYs). These real-world survival and QALY gains are consistent with the results of using the data from the EF-14 trial, which demonstrated a 1.25 life-years and 0.96 QALYs gain for TTFields + TMZ versus TMZ alone.
CONCLUSIONS: Using 8-year real-world survival data improves the accuracy of long-term outcome estimates while reducing reliance on extrapolation assumptions. The observed life-year and QALY gains with TTFields + TMZ in routine clinical practice reinforce its clinical value and support continued use in ndGBM. These findings serve as a foundation for future health economic evaluations, including cost-effectiveness analyses based on real-world data.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
EE421
Topic
Economic Evaluation, Real World Data & Information Systems
Disease
Oncology