Phase 1 study of concomitant tumor treating fields and temozolomide chemoradiation for newly diagnosed glioblastoma

Background Glioblastoma (GBM) is the most common and aggressive primary brain tumor and has limited effective therapies. Tumor treating fields (TTF; Optune Gio (R)) is an FDA-approved device with data supporting a significant survival benefit and minimal toxicity when added to maintenance chemotherapy. Uptake in clinical practice is not universal and might improve if a shorter duration of treatment is feasible. This phase 1 trial was designed to determine the safety and preliminary efficacy of TTF concomitant to chemoradiation.Methods Patients with newly diagnosed, histologically confirmed GBM were eligible. Following surgery, patients were treated with TTF concomitant to standard chemoradiation. The device continued through 2 monthly cycles of maintenance temozolomide with imaging and clinical assessments at regular intervals to assess toxicity and response. The primary endpoint was the safety and tolerability of combined modality treatment based upon the incidence and severity of adverse events. Secondary endpoints were overall survival (OS) and progression-free survival (PFS).Results Thirteen patients were enrolled. Dermatologic adverse events were frequent but limited to grade 1/2. There was only 1 serious adverse event possibly related to TTF and no patients were unable to complete the prescribed course of multimodality treatment due to TTF-associated toxicity. Twelve patients were evaluable for median and 6-month progression-free survival which were 8.5 months (mo) and 66.7%, respectively. Median and 12 mo overall survival were 16.0 mo and 83.3%, respectively.Conclusions TTF can be safely delivered in conjunction with chemoradiation. The potential for a finite TTF course merits further evaluation. Glioblastoma is an aggressive brain cancer. Optune Gio (R) is a device worn on the scalp that uses alternating electrical fields to stop cancer cells from dividing. Previous studies have shown that patients with glioblastoma live longer when they use Optune Gio (R) with maintenance chemotherapy after completing combined chemotherapy and radiation. The authors of this study wanted to see if it would be safe to use Optune Gio (R) earlier in treatment. To do this they treated 13 patients with newly diagnosed glioblastoma with Optune Gio (R) at the same time as chemotherapy and radiation therapy. Their results show that none of the patients had to stop treatment because of side effects from Optune Gio (R). The most common side effects related to treatment were skin changes. Approximately 83% of patients remained alive 12 months after starting the treatment.