18F-Fluciclovine PET-MRI in High-grade Glioma

Following radiation and immunotherapy, many pediatric participants with high-grade gliomas (HGG), including diffuse midline glioma (DMG), demonstrate radiographic findings suspicious of disease progression. Differentiating post-treatment changes from true tumor progression is paramount to clinical decision-making, as true tumor progression may warrant a change in treatment, while post-treatment changes are typically not an indication to change treatment. Unfortunately, conventional MRI cannot reliably distinguish between true progression and post-treatment changes. Therefore, finding a physiological correlate to delineate true progression from pseudo-progression is critical.

The overall objective of this current application is to evaluate 18F-fluciclovine PET imaging as a diagnostic biomarker for tumor progression compared to post-treatment changes in pediatric HGG. The long-term goal of this research is to accurately differentiate tumor progression from post-treatment changes in pediatric HGG using 18F-fluciclovine PET imaging.

Inclusion criteria

• 1. Histopathology-proven HGG (WHO grade III-IV) or DMG (WHO grade IV) or, in the case of DMG of the pons, imaging that is characteristic of Diffuse intrinsic pontine gliomas (DIPG) (diffusely infiltrating >=2/3 of the pons).
• 2. Measurable disease, measuring at least 1x1 cm.
• 3. Life expectancy of greater than 8 weeks.
• 4. Age > 1 years but < 21 years of age at enrollment.

For those without planned surgery:

• 1. Participants with clinical and/or radiographic suspicion of True progression (TP) or Pseudoprogression (PsP) during radiation but yet to have the initial post-radiation MRI scan.

or

• 2. Participants with suspicion for TP or PsP on first post-radiation MRI

For those with planned surgery:

• 1. Clinical or radiographic suspicion of tumor progression with plan to undergo surgery or biopsy.

Exclusion criteria

• 1. Inability to tolerate imaging procedures in the opinion of an investigator or treating physician.
• 2. Pregnant or breastfeeding participants.
• 3. Participant who would require sedation or anesthesia for imaging beyond standard of care (SOC).
• 4. Participants who weigh less than 8 kg.
• 5. Participants who cannot avoid contact with a pregnant woman or infant for at least 12 hours following injection.
• 6. Participants with a history of abnormal kidney function or creatinine >= CTCAE v5.0 grade 2 at time of study registration.

• Participants with primary tumors of the spinal cord.