Arginine and Whole Brain Radiation Therapy for the Treatment of Patients With Brain Metastases

This early phase I trial evaluates different administration techniques (oral or intravenous) for arginine and tests the safety of giving arginine with whole brain radiation therapy in patients who have cancer that has spread from where it first started (primary site) to the brain (brain metastases). Arginine is an essential amino acid. Amino acids are the molecules that join together to form proteins in the body. Arginine supplementation has been shown to improve how brain metastases respond to radiation therapy. The optimal dosing of arginine for this purpose has not been determined. This study measures the level of arginine in the blood with oral and intravenous dosing at specific time intervals before and after drug administration to determine the best dosing strategy.

Inclusion Criteria: * Diagnosis of brain metastases from any primary cancer * Planned to undergo whole-brain radiation therapy (Hippocampal avoidant is ok) * No systemic anti-neoplastic agent concurrent with WBRT (memantine is ok) * Not inpatient at the time of treatment start * Age 18 or older * Able to consent for self Exclusion Criteria: * Patient unwilling/unable to receive daily arginine treatment (IV or oral) for the 10 days of WBRT * Systemic therapy continuing during WBRT * Creatinine \> 1.5 x the upper limit of normal * Alanine aminotransferase (ALT) \> 6x the upper limit of normal * Patient planned to be treated as an inpatient * Age \< 18 years * Adult not able to consent for self * Pregnant * Prisoners * Cognitively impaired/impaired decision-making capacity