June 3, 2013 | by Nicole White
Brain tumors can be especially tricky to treat, and even when a main tumor mass is removed, individual cells may already have spread into normal brain tissue. Furthermore, the blood-brain barrier blocks most chemotherapy drugs. Now, results from a first-in-human safety trial suggest a way to overcome those obstacles.
The study was designed to test the safety and feasibility of a novel strategy for delivering cancer drugs directly to tumor sites without interfering with healthy tissue.
These neural stem cells, engineered to express a specific enzyme, were administered to the brain during tumor surgeries or biopsies in 15 patients with recurrent gliomas – an especially dangerous and hard-to-treat cancer. The patients were then given a prodrug – a benign form of a drug – designed to turn into a powerful cancer-killing agent when in contact with the enzyme from the stem cells. The patients were given one dose of stem cells and one week of the prodrug.
As hoped, the stem cells migrated to the tumors, and the prodrug was successfully converted into a cancer-fighting drug at the tumor site.
“We’re very pleased with the results,” said Jana Portnow, M.D., assistant professor of medical oncology and therapeutics research at City of Hope and principal investigator on the study. “We’ve already designed and applied for funding for a full phase I study.”
This study served as a solid proof-of-concept and safety. A new trial would begin to explore the treatment’s effectiveness. Patients in the new study would receive repeat doses of stem cells every two weeks followed by seven days of taking the prodrug. The stem cells would be administered using a catheter that would deliver them to the brain – meaning no surgery – and treatment would be given on an outpatient basis.
Results of the study are being presented at the annual meeting of the American Society of Clinical Oncology, May 31 through June 4.