Progression-free and overall survival were prolonged with maintenance therapy involving tumor-treating fields (TTFields) and chemotherapy in patients with a brain tumor who had completed standard chemoradiation, according to early research findings published in JAMA (doi:10.1001/jama.2015.16669).
Glioblastoma is a primary malignancy of the central nervous system in adults. Most patients die within 1 to 2 years of diagnosis. Attempts to improve the outcome for patients with glioblastoma during the last decade have failed when evaluated in large randomized trials.
Tumor-treating fields (TTFields) are a treatment that selectively disrupts the division of cells by delivering low-intensity, intermediate-frequency alternating electric fields via transducer arrays applied to the shaved scalp. Preclinical data demonstrated a synergistic antitumor effect with chemotherapy and TTFields, according to background information in the article.
The study involved 695 patients with glioblastoma who had completed chemoradiotherapy. The patients were randomized to receive maintenance treatment with either TTFields plus temozolomide (n = 466) or temozolomide alone (n = 229). Treatment with TTFields was delivered continuously (more than 18 hours/day) via 4 transducer arrays placed on the shaved scalp and connected to a portable medical device. Temozolomide was given for 5 days of each 28-day cycle. The study was conducted at 83 centers in the United States, Canada, Europe, Israel, and South Korea.
The trial was terminated based on the results of a planned interim analysis that included 210 patients randomized to TTFields plus temozolomide and 105 randomized to temozolomide alone. After a median follow-up of 38 months, the median progression-free survival was 7.1 months for the TTFields plus temozolomide group compared with 4 months for the temozolomide alone group. Median overall survival in the per-protocol population was 20.5 months for those who received TTFields plus temozolomide (n = 196) and 15.6 months for those who received temozolomide alone (n = 84).
The over-all incidence and severity of adverse events were similar between groups.
“In this interim analysis of 315 patients with glioblastoma who had completed standard chemoradiation therapy, adding TTFields to maintenance temozolomide chemotherapy significantly prolonged progression-free and overall survival,” the authors wrote.