Study Shows No Further Improvement in Prognosis of Patients with Recurrent High-Grade Glioma

Researchers found no significant difference in outcome for patients after tumor resection in study comparing drug combination of vocimagene amiretrorepvec (TOCA 511) with flucytosine (TOCA FC) to standard of care (SOC), in study found in JAMA Oncology.

This study tried to find a new treatment to improve prognosis in patients with high grad gliomas (HGGs), including grade III anaplastic astrocytoma (AA), after tumor resection.

The trial, labeled TOCA 511, took place from Nov. 30,2015 to Dec. 20,2019, following a total of 403 randomized patients. The patients were from 67 different centers in the United States, Canada, Israel, and South Korea. 201 patients were randomized into the Toca 511/FC group, and 202 were randomized into the SOC control group in which it was the investigators choice of single therapy: lomustine, temozolomide, or bevacizumab.

197 patients in the Toca 511/FC group received injection of 4mL of Toca 511 into the resection cavity wall at time of resection. Six weeks after resection patients began the first cycle with a seven-day course or oral Toca FC at 22mg/kg/d, repeating this every six weeks. 141 patients in the SOC group received either bevacizumab at 10mg/kg or lomustine at 110 mg/m2 every six weeks and temozolomide at 50mg/m2 daily.

The primary end points of the study were overall survival (OS) and secondary end points were safety, durable response rate (DRR), duration of durable response rate, and durable clinical benefit.

In Toca 511/FC the original 201 patients were included in the primary analysis, and the original 202 patients were included in analysis. At the final analysis 141 patients in the Toca 511/FC group and 130 patients in the SOC group had died.The median OS for Toca 511/FC was 11.10 months, and 12.22 months for SOC group. The secondary end points also did not show any statistically significant differences.

TOCA 5 did not meet its original objective to improve OS or secondary end points. Researchers found no significant differences between the two groups. Although the objective was not proven, the results may help future study’s designs.

Authors note that, “study limitation includes the small number of cycles of patients receiving treatment, the very small number of patients included in the subgroup analysis, insufficient number of blood and tissue samples collected for biomarker analysis, and variations of Toca 511 distribution in the resection cavity wall.”

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