GammaTile Cuts Treatment Delay in Glioblastoma

Standard of care for newly diagnosed glioblastoma calls for maximal safe resection followed by external beam radiation therapy (EBRT) and concurrent temozolomide, typically beginning 4 to 6 weeks after surgery. In that interval, rapid early progression has historically occurred in about half of patients, an outcome tied to worse survival, particularly in those with unmethylated MGMT.

GammaTile, a tile-based radiation therapy using cesium-131 sources, is designed to close that gap by initiating radiation at the time of resection rather than weeks later. In an interview, Clark C. Chen, MD, of Brown University, discussed results from a prospective, single-arm feasibility and safety trial (NCT05342883) conducted across 15 US centers evaluating resection plus tile-based radiation therapy combined with an abbreviated course of EBRT and temozolomide in patients with newly diagnosed, molecularly confirmed glioblastoma.

Among 67 patients with confirmed glioblastoma, 93% started EBRT plus temozolomide, with a median of 29 days from surgery to the start of chemoradiation. Just 6.0% of patients experienced rapid early progression, a marked reduction compared with historical rates of 50% to 80%. Treatment-related adverse events of grade 3 or higher occurred in 39% of patients, consistent with standard-of-care safety data. Median overall survival was 16.5 months for patients with unmethylated MGMT vs 28.0 months for those with methylated MGMT.

In this discussion, Chen walks through why the surgery-to-radiation delay exists, how tile-based radiation therapy is designed to eliminate it without increasing wound complications, and what the feasibility and safety data suggest about incorporating this approach into frontline treatment. He also outlines how these findings informed the design of the phase 3 trial now underway.

REFERENCE

Chen C et al. Outcomes of a feasibility and safety trial of tile-based radiation therapy with cesium-131 followed by external beam radiation therapy with concurrent and adjuvant temozolomide in patients with newly diagnosed glioblastoma (NCT05342883). J Clin Oncol. 44, 2011-2011(2026). doi:10.1200/JCO.2026.44.16_suppl.2011