Treovir Announces Opening of G207 Phase 2 Clinical Trial in Children with Recurrent Brain Tumors

Treovir, Inc. announced today the opening of a Phase 2 trial testing G207, an oncolytic HSV immunotherapy, in pediatric brain tumor patients.

G207 is being evaluated for efficacy in a single-arm Phase 2 study of 30 pediatric patients with high grade gliomas at first recurrence, a uniformly fatal form of pediatric brain tumors with no currently approved therapies.  The Phase 2 trial will evaluate efficacy (overall survival) and confirm safety of G207, an oncolytic HSV virus.  The trial is being conducted in collaboration with the Pediatric Brain Tumor Consortium, a National Cancer Institute (NCI)-supported consortium comprising 15 pediatric cancer centers, and is currently enrolling patients at Memorial Sloan Kettering Cancer Center and The University of Texas MD Anderson Cancer Center. NCI is part of the National Institutes of Health. Treovir anticipates that additional US and Canadian sites will open for enrollment in late 2024 and 2025.  ClinicalTrials.gov ID NCT04482933; PBTC 061 www.pbtc.org

“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” stated Michael Christini, CEO of Treovir. “There are no approved therapies for pediatric glioma and we anticipate that Phase 2 data will ultimately be used in support of a BLA filing for market approval of G207 offering a treatment option for patients in this critically underserved therapeutic area.”

About Treovir, Inc.

Treovir is a clinical-stage biopharmaceutical company focused on development and commercialization of oncolytic Herpes Simplex Viruses (oHSV) for treatment of malignant brain tumors in children. oHSV are genetically engineered viruses that are able to infect and kill malignant brain tumor cells, releasing tumor cell debris that elicits a potent immune-related cellular immunotherapy response. Treovir has been granted Fast-Track status for development of G207 by the FDA.  G207 also has orphan drug designations for gliomas and ependymomas, medulloblastomas and primitive neuroectodermal tumors in the US and for gliomas in the EMA.

Brain tumors are the most common solid tumors in children, and aggressive types like glioblastoma have an extremely low survival rate, as low as 10 percent five years after diagnosis. Malignant high-grade glioma accounts for 8 to 10 percent of pediatric brain tumors and survival rates have not improved in 30 years.  The median life expectancy of recurrent high-grade glioma is only 5.6 months.

In the Phase 1 dose-escalation study published in the New England Journal of Medicine in 2021, 12 pediatric patients 7 to 18 years of age with progressive high-grade glioma received a single intratumoral infusion of G207 alone or G207 in combination with radiation.  No dose-limiting toxic effects or serious adverse events were attributed to G207 by the investigators.  Radiographic, neuropathological, or clinical responses were seen in 11 patients.  The median overall survival for patients in the trial was 12.2 months (95% confidence interval, 8.0 to 16.4) which was more than double the typical survival rate for children with recurrent high-grade glioma and 5 of the 12 patients survived longer than 18 months, surpassing the expected survival for newly diagnosed children with high-grade glioma.  Additionally, G207 markedly increased the number of tumor-infiltrating lymphocytes for at least nine months after infusion, effectively turning immunologically “cold” tumors “hot,” an indication that the patient’s immune system can be activated to further eliminate the tumors.  NEJM 384(17): 1613-1622; ClinicalTrials.gov ID NCT02457845 

In addition to the Phase 2 study, G207 is being evaluated for safety in a Phase 1 clinical trial in children with recurrent or progressive malignant cerebellar gliomas or medulloblastomas. Treovir is providing G207 for the trial that is being conducted at MD Anderson Cancer Center and supported in part by an FDA grant awarded to Gregory K. Friedman, MD.  Dr. Friedman is the principal clinical investigator for both trials. ClinicalTrials.gov ID NCT03911388

Treovir is also in the early stages of planning a Phase 1/2 clinical study in newly diagnosed brain tumor patients beginning in 2026.