Phase 2 study of G207 for children with recurrent brain cancer opens
Trial to test how well virus-based G207 improves overall survival over 2 years
Treovir has launched a Phase 2 clinical trial to assess the safety and efficacy of G207, an experimental virus-based therapy, for pediatric recurrent high-grade glioma, a type of aggressive tumor that forms in the brain or spinal cord.
The study (NCT04482933) is recruiting up to 30 children and young adults, ages 3 to 21, who have a high-grade glioma that has recurred once after surgery and radiotherapy. Its focus is on how well G207 improves overall survival over 24 months when infused slowly into the tumor one day before a single dose of radiation.
It’s being sponsored by the Pediatric Brain Tumor Consortium, which is supported by the National Cancer Institute. Patients are being recruited at Memorial Sloan Kettering Cancer Center in New York and The University of Texas MD Anderson Cancer Center with plans to expand to other sites in the U.S. and Canada in 2024 and 2025.
“With the opening of the Phase 2 study Treovir expects to expand on the positive data obtained from the Phase 1 study in pediatric patients completed in 2021,” Michael Christini, CEO of Treovir, said in a company press release.
11 patients in Phase 1 study of G207 showed signs of tumor response
In that previous Phase 1 study (NCT02457845), 12 children and adolescents with high-grade glioma were treated with G207, either alone or with radiation. Eleven patients showed signs of tumor response, and no serious side effects were reported with G207.
The average survival time was 12.2 months — more than double the expected for recurrent high-grade glioma — and five patients survived more than 18 months. G207 also activated the immune system, increasing the number of tumor-fighting immune cells that invaded the glioma.
A glioma forms in glial cells, which usually support and protect the nerve cells in the brain and spinal cord. This type of tumor can be low grade or high grade, depending on how abnormal the tumor cells look under a microscope and how quickly the tumor grows, spreads, and recurs after therapy.
Currently, “there are no approved therapies for pediatric glioma,” Christini said, “and we anticipate that Phase 2 data will ultimately be used in support of a [biologics license application] filing for market approval of G207 offering a treatment option for patients in this critically underserved therapeutic area.”
G207 contains a virus that has been genetically modified to attack tumor cells while sparing healthy ones. It works by infecting and killing tumor cells. As tumor cells die, G207 spreads further, coaxing immune cells to turn against the glioma. The patient’s own immune response is thought to play a role in how well G207 works.
In the Phase 2 study, each patient will receive 100 million plaque-forming units of G207, infused into MRI-defined tumor regions over six hours via up to four catheters. Within 24 hours, a single 5 Gy radiation dose will be delivered to the tumor.
Phase 2 trial to gauge changes in overall survival, monitor safety
In addition to the main goal of watching for changes in overall survival compared with historical controls, the study will monitor patients for side effects for up to five years. It will also check for virus shedding into the saliva, eyes, and blood over 24 months.
A Phase 1 study (NCT03911388) running at MD Anderson Cancer Center is also testing the safety of G207 in patients with recurrent or progressive malignant cerebellar glioma or medulloblastoma, a fast-growing tumor that forms in the cerebellum, located in the lower, back part of the brain. Another study, in newly diagnosed patients, is planned for 2026.
G207 has received fast track designation in the U.S., which means it could get priority review, helping to make it available to patients sooner if it is approved. It also received orphan drug designation for glioma in the European Union, which may help speed its clinical development and regulatory review.
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