Tocagen Inc. announced its randomized, controlled Phase 2/3 clinical trial, called Toca 5, is now enrolling patients in South Korea. The trial is ongoing in the United States, Canada and Israel. The study compares a cancer-selective virus, Toca 511 (vocimagene amiretrorepvec), in combination with Toca FC (extended-release 5-fluorocytosine), to standard of care in patients with first or second recurrence of glioblastoma or anaplastic astrocytoma who are undergoing resection. The primary endpoint for the Toca 5 clinical trial is overall survival with secondary endpoints including objective response rate. Investigators may choose chemotherapy (lomustine or temozolomide) or antiangiogenic therapy (bevacizumab) for the control arm. High grade gliomas are among the most common and aggressive primary brain cancers. The two most common forms of high grade glioma are glioblastoma and anaplastic astrocytoma. Standard treatment for newly diagnosed high grade glioma includes safe surgical removal of as much of the tumor as possible followed by radiation therapy and chemotherapy. Despite these treatments, the tumor typically recurs. Median survival after recurrence is approximately seven to nine months. A total of 126 patients have been treated in Tocagen’s Phase 1, ascending-dose studies. Clinical data were recently published in Science Translational Medicine. In the subset of patients in the higher dose cohorts that mirror the patient population under evaluation in the ongoing Toca 5 trial, a clinical benefit rate of 41.7% was reported at the 21st Annual Scientific Meeting and Education Day of the Society for Neuro-Oncology. This included 3 complete responses, 2 partial responses and 5 patients with stable disease (N=24). All patients with an objective response remain alive and in response.