Getting drugs into the brain to treat tumors and other ailments has for years proven a difficult hurdle to overcome, but neurosurgeons have begun using an MRI-based technique to guide the delivery of gene therapies to target brain cancers in real time.
Surgeons at the University of California, San Diego School of Medicine and Moores Cancer Center used MRI navigational technology from MRI Interventions to inject the investigational gene therapy Toca 511, or vocimagene amiretrorepvec, into a brain tumor to make it more susceptible to chemotherapy. Tocagen's Toca 511 is a retrovirus that replicates in cancer cells such as glioblastoma, according to a UCSD release. And MRI Interventions' ClearPoint technology helps target it directly into those tumors.
Tocagen is currently enrolling a Phase I trial of its Toca 511 and Toca FC, the oral formulation to be used in combination with the MRI-guided therapy. The controlled-release Toca FC crosses the blood-brain barrier to selectively target the areas where Toca 511 has accumulated in a tumor.
"With chemotherapy, just about every human cell is exposed to the drug's potential side-effects," Clark Chen, chief of stereotactic and radiosurgery at UCSD, said in a statement. "By using the direct injection approach, we believe we can limit the presence of the active drug to just the brain tumor and nowhere else in the body. With MRI, we can see the tumor light up in real time during drug infusion. The rest of the brain remains unaffected, so the risk of the procedure is minimized."
"Inevitably, almost all glioblastoma patients fail currently available therapy," said principal investigator Santosh Kesari of Moores Cancer Center. "The challenge, in part, is knowing if current drugs are actually penetrating the tumor. This MRI-guided approach will help us deliver this drug into the tumor directly to see if the drug is working. This approach may lead to new treatment options battling several other types of brain cancers."
- here's the UCSD release
Editor's Corner: ClearPoint MRI-guided device sheds light on drug delivery to the brain