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).

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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.”

Reference

  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]