Diffuse pontine gliomas (DIPG) are one of the most lethal pediatric tumors. All treatment approaches for these tumors have failed, leaving a terrible prospect with median survival under one year, and survival at 5 years virtually of zero. Moreover, most of the long term survivors suffer from long-term side effects of the aggressive treatment. Thus, new therapeutic strategies are required that allow not only for more effective treatments of these tumors but also that defer the severe side effects derived from the current therapeutic choices. DNX-2401 is an oncolytic virus engineered to replicate specifically in tumor cells with an abnormal retinoblastoma (RB) pathway. Moreover, this virus infects cells through integrins, which are more abundant in glioma cells. Here we propose a phase I, unicentric, non-randomized clinical trial to study the safety and potential efficacy of intratumoral administration of DNX-2401 in DIPG. The virus administration will be done after stereotactic tumor biopsy, using the same trajectory, after verification of catheter position with intraoperative MRI. After 3-4 weeks patients will receive standard radiotherapy and/or chemotherapy. The primary objective is to confirm the safety of the target dose known from adults trials. Secondary endpoints are overall survival at 12 months (OS12), percentage of responses and induced immune response against tumor. The follow up includes close monitoring of neurological status, blood tests and brain MRI. If this trial shows evidence of safety and efficacy will propel a multicenter clinical trial.