Early use of electrical device doesn’t extend glioblastoma survival

Starting the electrical therapy Optune Gio during radiation therapy and chemotherapy, rather than after it as indicated, did not extend survival in people with newly diagnosed glioblastoma, an aggressive form of glioma, in a clinical trial.

Those are the top-line results from the Novocure-sponsored Phase 3 TRIDENT clinical trial (NCT04471844), which evaluated whether earlier introduction of Optune Gio improves clinical outcomes in adults with glioblastoma.

“The study did not meet its primary endpoint, but the results from TRIDENT demonstrated the feasibility and safety of initiating [Optune Gio] therapy during chemoradiation,” Uri Weinberg, MD, PhD, chief medical and innovation officer at Novocure, said in a company press release. “We look forward to sharing additional analyses from this trial, which may inform future treatment approaches for patients with specific characteristics.”

TRIDENT data have been accepted for presentation at the American Society for Radiation Oncology (ASTRO) 2026 Annual Meeting, to be held in Boston in September.

“TRIDENT represents the largest glioblastoma trial focused on optimizing the integration of [Optune Gio] therapy into standard chemoradiotherapy,” said Wenyin Shi, MD, PhD, a professor at Thomas Jefferson University in Pennsylvania. “Although the study did not meet its primary endpoint, it reaffirmed the clinical value of [Optune Gio] therapy and demonstrated promising signals that earlier initiation of [Optune Gio] treatment may improve outcomes for selected patients.”

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Standard treatment for glioblastoma typically involves surgery followed by chemoradiation (a combination of radiation and chemotherapy), and then a maintenance phase of continued chemotherapy.

Optune Gio uses Tumor Treating Fields (TTFields), low-intensity electric fields delivered via patches applied to a patient’s skin to disrupt the growth of cancer cells. These cells are more susceptible to the therapy than healthy cells because they divide much faster.

It’s used in combination with the standard-of-care chemotherapy Temodar (temozolomide) after completion of chemoradiation therapy.

Optune Gio is approved in the U.S. and Canada to treat recurrent and newly diagnosed glioblastoma. TTFields therapy was also recently approved in the U.S. as Optune Pax to treat locally advanced pancreatic cancer.

Novocure launched TRIDENT to determine whether starting Optune Gio therapy at the start of chemoradiation improves survival compared with starting it during the maintenance phase.

TRIDENT enrolled 981 adults, with a median age of 60, with newly diagnosed glioblastoma. Shortly after surgery, participants were randomly assigned to receive Optune Gio either at the start or after chemoradiation. All patients continued Optune Gio and maintenance Temodar after chemoradiation ended. The study’s main outcome measure was overall survival.

Pre-study patient characteristics were similar between the two groups. Overall, 38% of patients scored 70 or 80 on the Karnofsky Performance Status measure, indicating they could perform daily activities with some effort or assistance. The scale ranks patients’ physical independence on a scale from 0 to 100, with higher scores pointing to better functioning and a greater ability to tolerate treatments like chemotherapy.

Regarding tumor biology, 39% had a methylated MGMT promoter, a molecular marker associated with a better response to Temodar, and 5% had IDH-mutant tumors, which are generally associated with slower tumor growth, better responses to treatment, and a more favorable prognosis.

Fifty-one percent of the participants had undergone a gross total resection (full removal of visible tumor), 37% had a partial resection, and 12% had a biopsy alone. About 25% of patients across both groups did not reach the maintenance phase of treatment.

The trial did not meet its primary endpoint, meaning there was no significant difference in median overall survival between the early-start and maintenance groups (17.7 months vs. 17.5 months). The survival outcomes in both groups were similar after one year (70.9% vs. 72%), two years (33.9% vs. 31.6%), and three years (22.5% vs. 18.4%).

Optune Gio was well tolerated, including when initiated during chemoradiation. No new safety signals were observed, and device-related safety was consistent with results from prior clinical studies of Optune Gio therapy in glioblastoma.