New antibody therapy shows promise Pediatric brain - Video

Effective and safe treatments are needed for medulloblastoma, the most common type of cancerous brain tumor in children, especially whose cancer has spread to the spinal cord. A recent phase I clinical trial led by researchers has generated promising results for a new blocking antibody therapy that targets a protein critical to medulloblastoma cells' ability to multiply and spread. The findings are published in Clinical Cancer Research, a journal of the American Association for Cancer Research.

The antibody, called TB-403, recognizes placental growth factor (PlGF), over-expressed in some types of malignant tumors. The MGH research team previously showed that placental growth factor and its receptor neuropilin 1 (NRP1) are often overexpressed in human medulloblastomas and are required for its growth and progression in experimental models in mice.

That work also demonstrated that blocking the PlGF/NRP1 pathway in medulloblastoma models caused tumor regression, decreased spread to the spinal cord, and prolonged survival.

The investigators' phase I, open-label, multicenter dose-escalation study enrolled 15 children with relapsed or refractory medulloblastoma that did not respond to standard treatments. Patients received increasing doses of the anti-human placental growth factor antibody TB-403 (20 mg/kg, 50 mg/kg, 100 mg/kg, and 175 mg/kg), and all patients received two doses of TB-403 in the first cycle of treatment.

The maximum tolerated dose defined in clinical trials as the highest dose of a drug that does not cause unacceptable toxicity-was not reached. Moreover, although there were no partial tumor responses (significant reductions in tumor size) in this treatment refractory population, seven of 11 patients experienced disease stabilization-stoppage of progression-and which persisted for more than 100 days in four of those patients.

The investigators concluded that TB403 treatment was well tolerated and induced stable disease in some medulloblastomas in a setting with no effective treatments available.

These findings indicate that treatment with TB-403 should be tested in larger studies of children with advanced medulloblastoma and perhaps at earlier stages, in combination with standard therapies, concluded the researchers.

Reference: "New antibody therapy shows promising phase I clinical trial results for advanced, treatment-refractory pediatric brain cancer; MASSACHUSETTS GENERAL HOSPITAL,Clinical Cancer Research.