Participants in this research study are people who are likely to have, or have been diagnosed with a brain tumor, for which surgical removal (or "resection") is the standard of care treatment. The purpose of this study is to see whether a drug called SBK2-ICG can be used to locate the true outline or "edges" of the tumor. If the tumor outline could be accurately identified at the time of surgery, the fullest extent of tumor could be removed while sparing the normal brain tissue.

Participants will receive SBK2-ICG about an hour before they receive surgery. The extent of surgery to be performed will not be changed in this study. Researchers will only use the information from the study to determine the best SBK2-ICG dose for accurate tumor margin (i.e., the border or edges of the tumor with the normal brain) detection so that no tumor is left behind.

The use of SBK2-ICG in brain tumors is experimental, which means that the U.S. Food and Drug Administration (FDA) has not approved it for use to locate brain tumors. However, the use of the drug SBK2-ICG for the purposes of this study is on file with the FDA.

Treating people with serious brain tumors is challenging, and the outlook for these people is poor. On average, people survive less than one year after their are diagnosed. How long someone lives after diagnosis and treatment may depend on how much of the tumor is able to be removed with surgery. However, it can be difficult for surgeons to tell the difference between where the tumor is and where healthy brain tissue is using standard white light surgical microscope illumination. Because of this, new methods to help surgeons see tumor borders more clearly during surgery could be valuable.

Fluorescence imaging may be one method that can help surgeons see tumor borders more clearly. Previous studies have used fluorescence imaging to better visualize tumors, but no previous studies have used SBK2-ICG. In fact, the use of SBK2-ICG is conceptually different than other studies.

Currently, the only FDA approved drug used in fluorescent imaging for visualizing brain tumors during surgery is called 5-aminolevulinic acid, or 5-ALA. 5-ALA is naturally metabolized in human cells to something called PpIX. When people are given 5-ALA before surgery, it gets turned into PpIX, which can then be excited by fluorescent light at wavelengths of 400-410 nm. Because tumor cells and healthy cells metabolize 5-ALA in different ways, PpIX tends to accumulate in epithelial and malignant cells, including brain tumor cells. In a review of previous studies, using 5-ALA was associated with better removal of tumor tissue, longer overall survival, and longer progression-free survival. However, 5-ALA only weakly detects tumor borders and does not identify infiltrative cells on the edges of tumors. Also, even thin barriers of normal cells can make it difficult for surgeons to see 5-ALA, which makes it difficult to tell the difference between tumor tissue and healthy tissue. Because of this, it would be helpful to use a drug that emits a light that more deeply penetrates brain tissue so that surgeons can see tumor tissue and healthy tissue better.

SBK2-ICG is different than 5-ALA because it is not metabolized by the human body. Instead, SBK2-ICG attaches to a unique piece of cells that accumulates in tumors. SBK2-ICG can also be excited at a wavelength of 789 nm, rather than the wavelength of 400-410 nm that 5-ALA is excited at. SBK2-ICG gives off a near infrared light when it is excited, making it easier to see the borders of tumors. It also helps with seeing deep inside of the tumor. Using SBK2-ICG and fluorescent light has been shown to identify more than 99% of tumor cells in rodent xenograft models of human brain tumors in the lab.

Researchers want to assess the safety of SBK2-ICG in people with brain tumors who are already planning to have surgery to remove their tumor and see how SBK2-ICG compares to standard practices in identifying tumor tissue versus healthy tissue.

Inclusion Criteria:

• Participants must have suspected or confirmed untreated malignant brain tumors
• Participants must have received no prior therapies for this disease.
• Participants are 18 years of age or older. Because no dosing or adverse event data are currently available on the use of SBK2-ICG in individuals under 18 years of age, children are excluded from this study.
• Karnofsky Performance status ≥ 60%
• Glioma is located in the supratentorial region of the brain.
• Tumor is suitable for resection on the basis of imaging studies and participant and surgeon must plan resection
• Able and willing to undergo MRI scan.
• Participants must have the ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

• Pregnant individuals or those who are breast feeding.
• Individuals with AST, ALT, ALP, or bilirubin >2.5x normal upper limit any time during the previous 2 months.
• Individuals with plasma creatinine > 2.5 mg/dL.
• Individuals without a probable or expected grade IV glioma.
• Individuals not planning surgery on glioma.
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to ICG or other agents used in this study.
• Note: A baseline blood sample will be drawn for creatinine, AST, ALT, ALP, and bilirubin to verify whether or not this exclusion criterion is met.