Tumor-treating Fields Useful to Improve Glioblastoma Outcomes
Adverse event rates were similar in both trial groups, though patients treated with TTFields were much more likely to have mild to moderate skin toxicity.
Using tumor-treating fields (TTFields) with maintenance temozolomide improves progression-free survival (PFS) and overall survival (OS) among patients with glioblastoma, according to the final analysis of a phase 3 study published in JAMA.1
Although resection and maintenance temozolomide have improved outcomes among patients with glioblastoma, survival rates remain poor, with as few as 1 in 20 patients surviving for longer than 5 years. TTFields, which are applied directly to the scalp, induce mitotic arrest in glioblastoma cells, and showed synergistic activity with temozolomide in tumor models.
For this open-label phase 3 study (ClinicalTrials.gov Identifier: NCT00916409), researchers randomly assigned 695 participants 2:1 to receive maintenance temozolomide with TTFields (466 patients) or temozolomide alone (229 patients). The median patient age was 56 years; all patients had undergone tumor resection or biopsy and completed concomitant radiochemotherapy.
The median PFS was 6.7 months in the TTFields group vs 4 months in the temozolomide only group (P < .001); the median OS was 20.9 months in the TTFields group vs 16 months in the temozolomide only group (P < .001). Improvement was seen in all subgroups.
Patients in the TTFields group who underwent biopsy rather than gross total resection, however, had better a hazard ratio for OS (.50 vs .70, respectively).
Adverse event rates were similar in both groups, though patients treated with TTFields were much more likely to have mild to moderate skin toxicity (52% vs no patients in the temozolomide group).
The authors concluded that “the addition of TTFields to maintenance temozolomide chemotherapy vs maintenance temozolomide alone […] resulted in statistically significant improvement in progression-free survival and overall survival.”
1. Stupp R, Taillibert S, Kanner A, et al. Effect of tumor-treating fields plus maintenance temozolomide vs maintenance temozolomide alone on survival in patients with glioblastoma: a randomized clinical trial. JAMA. 2017 Dec 19. doi: 10.1001/jama.2017.18718 [Epub ahead of print]