Abstract
BACKGROUND
Tumor Treating Fields (TTFields) are electric fields that disrupt processes critical for cancer cell viability and tumor progression by a multi-modal mechanism of action. TTFields therapy is FDA-approved for newly diagnosed glioblastoma (ndGBM) based on results from the randomized, phase 3 EF-14 study (NCT00916409). We assessed the overall survival (OS) benefit of adding TTFields therapy to standard of care (SOC) for patients with ndGBM treated in clinical practice, as well as the relationship between OS and device usage rate.
MATERIAL AND METHODS
A systematic literature review (PubMed, Embase, and Cochrane Library) identified single-cohort and comparative clinical studies that assessed survival in patients with ndGBM who received TTFields therapy. Inter-study heterogeneity was quantified using the Higgins I2 statistic and Cochran Q test. A distribution-free random-effects method was used to pool survival curves.
RESULTS
Nine studies were identified that evaluated survival with TTFields therapy in ndGBM. Of these, the 7 studies (1430 patients) that compared TTFields therapy with SOC to SOC alone were included in a pooled analysis for OS. The pooled data showed significantly longer OS with TTFields therapy/SOC vs SOC alone (hazard ratio [HR]: 0.63; 95% CI, 0.53-0.75; P<0.001). A sensitivity analysis indicated that the effect was robust and independent of any individual study. In post-approval studies, pooled median OS was 22.2 months (95% CI, 17.3-42.6) for TTFields therapy/SOC and 17.3 months (95% CI, 13.6-22.0) for SOC alone. Gross total resection was generally more prevalent in the real-world setting, irrespective of TTFields use. Among studies evaluating device usage, an average usage rate of ≥75% was associated with prolonged OS vs <75% usage (pooled HR: 0.60; 95% CI, 0.48-0.73; P<0.001).
CONCLUSION
Pooled analysis of comparative TTFields therapy studies suggests a significant survival benefit with TTFields added to SOC for patients with ndGBM, and that a recommended 75% usage rate may be clinically meaningful in the real-world setting.