Glioblastoma has a poor prognosis with limited therapeutic options. To date, almost all therapeutic agents that showed promise in in vitro assays, preclinical trials, or even in early clinical trials have failed to make a substantial impact on the survival of patients with high-grade glioma. One major obstacle for small molecules, therapeutic proteins or immune cells, remains the blood brain barrier, which often prevents the efficient delivery of agents to the tumor. To address this delivery issue, we developed a cellular vector, where implanted modified post-mitotic Migratory Cortical Inhibitory Interneuron Precursors (MCIPs) migrate to high-grade glioma by chemoattraction to locally secrete a therapeutic protein. The inhibitory interneurons of the cerebral cortex originate predominantly in the ventral/subcortical portion of the telencephalic neural tube. During fetal brain development, MCIP migration is guided over long distances by chemorepulsant and chemoattractant factors. Remarkably, several of the MCIP chemoattractant factors are also secreted by high-grade gliomas. Indeed, our in vitro and in vivo data show that MCIPs robustly migrate to the majority of glioblastoma evaluated. As a proof of principle, we modified the MCIPs to secrete bispecific T-cell engagers (BiTEs), in essence two linked antibodies that connect 2 antigens of choice. We chose to link the EGFR tumor antigen to CD3 (T-cell receptor) on T-cells to create an adaptor molecule that induces an anti-tumor response of resident and supplied T-cells by bridging a tumor antigen and the T-cell receptor. We find that implanted BITE-secreting MCIPs significantly extended survival of mice injected with high-grade glioma. Therefore, we conclude that the use of MCIPs as a delivery vector for therapeutic agents could revolutionize the way we treat glioblastoma, as they allow for the local delivery of therapeutic agents in high concentrations, bypassing the need for these agents to cross the blood brain barrier while reducing the risk for systemic toxicities outside of the brain.