Background: Diffuse intrinsic pontine gliomas (DIPG) are inoperable and highly resistant tumors to chemotherapy and irradiation. DIPG has the worst prognosis among all pediatric brain tumors and the overwhelming majority of patients die within 6–18 months after diagnosis. Methods: We retrospectively reviewed the charts of six DIPG patients treated with chemoradiotherapy (daily carboplatin and oral etoposide in five patients and temozolomide in one patient) followed by maintenance chemotherapy consisting of irinotecan, temozolomide, and bevacizumab at our institution between January 2007 until December 2007. Results: Event-free survival (EFS) and overall survival (OS) were 10.4 ± 3.08 and 14.6 ± 3.55 months, respectively. Side effects in the patients included hypertension in two, abdominal cramping and diarrhea in four, and neutropenia in five patients. Conclusions: This augmented regimen was associated with increased but tolerable toxicity and a modest increase in EFS and OS when compared with published literature in patients with DIPG (median EFS and OS of 6.1 and 9.6 months, respectively). More effective therapies are desperately needed.

Pediatric high-grade glioma (pHGG) and brainstem gliomas are some of the most challenging cancers to treat in children, with no effective therapies and 5-year survival at ~2% for diffuse intrinsic pontine glioma (DIPG) patients. The standard of care for pHGG as a whole remains surgery and radiation combined with chemotherapy, while radiation alone is standard treatment for DIPG. Unfortunately, these therapies lack specificity for malignant glioma cells and have few to no reliable biomarkers of efficacy. Recent discoveries have revealed that epigenetic disruption by highly conserved mutations in DNA-packaging histone proteins in pHGG, especially DIPG, contribute to the aggressive nature of these cancers. In this review we pose unanswered questions and address unexplored mechanisms in pre-clinical models and clinical trial data from pHGG patients. Particular focus will be paid towards therapeutics targeting chromatin modifiers and other epigenetic vulnerabilities that can be exploited for pHGG therapy. Further delineation of rational therapeutic combinations has strong potential to drive development of safe and efficacious treatments for pHGG patients.