Diffuse midline glioma (DMG) refers to a rare and extremely aggressive brain tumor that is most common in children. Chemotherapy and radiation are the current standards-of-care. Unfortunately, even with these therapies, DMG still comes with a poor prognosis; the median overall survival rate is under one year following radiation. Finding new and effective therapeutic options is urgent to improve outcomes within this patient population. Immuno-oncology company Oncotelic Inc. is currently working to address this need through the development of OT-101. According to a November 2022 news release, the company recently submitted clinical trial protocol to initiate its G101 study to evaluate OT-101’s safety and tolerability.

Also known as trabedersen, OT-101 is an intraventricularly administered novel antisense oligodeoxynucleotide and anti-TGF-β2 ribonucleic acid therapeutic that is being developed for a variety of indications. According to Oncotelic, these indications include:

• Pancreatic carcinoma
• Colorectal carcinoma
• Prostate carcinoma
• Renal cell carcinoma
• Malignant melanoma
• SARS
• COVID-19

OT-101 has proved to be safe and efficacious in Phase 2 studies on glioblastoma, pancreatic cancer, and melanoma. In relation to diffuse midline glioma, OT-101 has received both Orphan Drug and Rare Pediatric Disease designations.

An Overview of Diffuse Midline Glioma (DMG)

Until relatively recently, diffuse midline gliomas were referred to as diffuse intrinsic pontine gliomas (DIPG). These brain tumors begin in the brain stem, which normally controls heart rate and breathing, among other bodily functions. Diffuse midline glioma is the second most common form of primary brain tumor in children. They can be considered low-grade (grades I or II) or high-grade (grades III and IV). Overall, the cause is unknown. However, many hypothesize that DMG formation could be related in some way to brain development. These tumors are most common in those between ages 5-10. Symptoms can (but do not always) include:

• Speech difficulties
• Nausea and vomiting
• Fatigue
• Headaches (that are often worse in the morning)
• Difficulty chewing and swallowing
• Blurred or double vision
• Drooping eyelids
• Uncontrolled eye movements
• Issues with balance and coordination
• Difficulty walking
• Hydrocephalus