Recent publications reveal encouraging outcomes from two initial trials in treating glioblastoma, an aggressive brain cancer known for claiming the lives of notable figures like John McCain and Beau Biden. This cancer, only identifiable at stage 4, has a mere 10% five-year survival rate, and no new effective drugs have been approved in the last 20 years, according to Dr. Michael Vogelbaum from Moffitt Cancer Center.
These small-scale trials, involving just nine patients, used a novel approach of an existing blood cancer treatment and demonstrated both safety and tumor size reduction. However, larger studies are required to ascertain long-term efficacy.
The trials explored the potential of chimeric antigen receptor T-cell therapy (CAR-T therapy), a personalized immunotherapy initially developed for blood cancers. This therapy involves modifying a patient’s own immune cells to target specific tumor proteins, and then reintroducing these cells into the body.
While effective against homogeneous blood cancers, applying CAR-T therapy to solid tumors like glioblastoma is more complex due to the heterogeneity of these tumor cells. Dr. Marcela Maus from Massachusetts General Cancer Center, who led one of the trials, notes the challenge posed by glioblastoma’s varied cell types.
Both trials experimented with CAR-T cells targeting two proteins instead of one, hoping to more effectively combat solid tumors. Dr. Vincent Lam from Johns Hopkins Cancer Center, not involved in the trials, highlights the advantage of targeting multiple proteins.
In Maus’ study, published in The New England Journal of Medicine, three patients were treated with T-cells engineered to target the EGFR protein and its variant, abundant in glioblastoma tumors. These cells were injected directly into the cerebrospinal fluid, a more targeted approach compared to the intravenous method used in blood cancer.
The second trial, published in Nature Medicine, involved six patients with recurrent glioblastoma. This study also adopted localized delivery of immunotherapy and included radiation before treatment. Both trials showed tumor size reduction and an increase in active CAR-T cells in the spinal fluid.
Despite promising results, the effects were not long-lasting. Both trials are continuing with adjustments in their approaches. Maus suggests combining CAR-T therapy with radiation and chemotherapy might enhance effectiveness, and other researchers are considering cancer-fighting vaccines in tandem.
The trials indicate a significant step in using CAR-T therapy for brain tumors, yet the long-term effectiveness remains to be seen. The ongoing research aims to refine the therapy to make it a viable treatment for glioblastoma.