Engineered HSV-1 M032 for the Treatment of Children and Adults With Newly Diagnosed Diffuse Midline Glioma After Standard of Care Radiation

Inclusion Criteria: * Age ≥ 36 months * Newly diagnosed pathologically proven diffuse midline glioma (DMG) (H3 K27M mutant) or radiographic and/or pathologically proven pontine DMG (tumors with an epicenter in the pontine and diffuse involvement in at least 50% of the axial diameter of the pons) * Patient must have received standard of care radiation ≥ 4 but ≤ 8 weeks prior to study enrollment Note: The eligibility determination, enrollment, pre-surgical planning, and M032 administration must be completed within 8 weeks of radiation therapy completion. * The tumor characteristics for enrollment are as follows: * The lesion must be ≥ 1.0 cm and ≤ 4.0 cm in diameter and surgically accessible as determined by MRI * For patients diagnosed with supratentorial DMG, tumors larger than 4.0 cm may be eligible if they can be surgically debulked to ≤ 4.0 cm * Patients must have fully recovered from acute treatment-related toxicities prior to entering this study. The study entry timepoint is defined as the time of consent * Previous treatment guidelines (if applicable): * Monoclonal antibody (i.e., bevacizumab): patient must have received last dose ≥ 21 days prior * Radiation: Patients must have received their last fraction of radiation ≥ 4 weeks and ≤ 8 weeks prior to study entry * Temozolomide: Patients must have received their last dose of chemotherapy ≥ 4 weeks prior Normal hematological, renal, and liver function as defined below: * Hemoglobin \> 9g/dL * White blood cell ≥ 3,000/…