Perhaps the most difficult challenge in treating diffuse midline gliomas is the inability to safely deliver drugs directly into the brain tumor. This is due to something called the blood-brain barrier (BBB), a wall of cells that are there to protect toxins from entering the blood in the brain. So, while chemotherapy can be very successful in treating other cancers, the BBB blocks most of the drug from getting into brain tumors, presenting a major limitation in treating the disease.
Dr. Mark Souweidane has dedicated more than two decades of his career to curing childhood brain cancer. In 2022, he received a ChadTough Game Changer grant to focus on the development of a comprehensive direct drug delivery platform using focused ultrasound (FUS) for the treatment of DMGs. By combining FUS with innovative drug delivery techniques, such as convection enhanced delivery (CED), intrathecal (IT) injection, and intravenous (IV) infusion, Dr. Souweidane and his team sought to optimize drug penetration into the tumor tissue and improve treatment efficacy. We’re excited to share some of his findings that could potentially help solve one of the biggest challenges to treat complicated brain tumors.
During the first year of funding, Dr. Souweidane and his team developed a comprehensive experimental design to assess the effectiveness of different drug delivery routes and the influence of FUS. The study involved a series of experiments conducted in mice to ensure findings are applicable in human patients. The team used Dextran, a fluorescent model drug with different molecular weights, to validate their hypothesis.
Results indicated that IV administration coupled with focused ultrasound induced blood-brain barrier opening (FUS-BBBO) will successfully enhance delivery of dye into specific areas of the brain targeted for sonication. However, the team also found that measurable dye in the same targeted areas was consistently less after IT administration.
FUS enhances the distribution volume of dye after CED. Furthermore, a shorter time of residence was observed when CED was coupled with FUS-BBBO application when compared to CED alone.
Dr. Souweidane and his team will continue to explore the efficacy of novel drug combinations, now specifically tailored for the treatment of diffuse intrinsic pontine glioma (DIPG). If positive results are observed in mice, the next step is to add radioactive labels to the identified drugs. This process creates theranostic agents, which are important because they combine both treatment and diagnostic abilities in one compound. So, not only do these drugs have potential healing properties, but they also contain elements that allow researchers to see where they’re going and how they’re working in real-time within the tumor. This approach allows scientists to target the tumor precisely and get important feedback on how well the treatment is working.