Biodegradable Brain Implant Prevents Glioblastoma Recurrence

Preventing glioblastoma from returning after surgery remains one of the greatest challenges in neuro-oncology. Even after tumor removal and radiochemotherapy, this aggressive brain cancer almost always recurs, largely due to the tumor’s ability to suppress the immune system. Now, a biodegradable wafer implanted directly into the brain cavity to slowly release immune-modulating drugs can stop the cancer from coming back.

The wafer named CANDI was developed by researchers at Massachusetts General Hospital (Boston, MA, USA) and Harvard Medical School (Boston, MA, USA) and is designed to reprogram myeloid cells — immune cells that are abundant in glioblastoma and typically promote tumor growth — into active defenders against residual cancer. CANDI is made from a crosslinked sugar-based polymer (cyclodextrin) and engineered to deliver a controlled combination of immune-modulating drugs directly to the surgical cavity.

By targeting tumor-associated macrophages, the implant aims to change the tumor microenvironment from immunosuppressive to immune-activating. After testing the material in vitro, the team implanted the wafers into mice following glioblastoma surgery and assessed outcomes through imaging, immune profiling, and survival studies. They also tested the wafer on freshly resected human glioblastoma samples in the laboratory.

Once absorbed by tumor-associated macrophages, the wafer reprogrammed these cells to produce interleukin-12, a potent immune-stimulating signaling molecule. This, in turn, drew cancer-killing T cells to the former tumor site. More than half of the treated mice remained tumor-free long term — a significant improvement over the typical rapid recurrence seen in this cancer. Human tumor samples showed similar immune activation, suggesting strong translational potential.

The study, published in Nature Biomedical Engineering, offers early proof-of-concept for a new type of immunotherapy administered during surgery. As there is currently no FDA-approved immunotherapy for glioblastoma, an approach like CANDI could complement existing treatments such as radiation, chemotherapy, and other experimental immunotherapies, potentially improving long-term outcomes.

Researchers are now optimizing the wafer design for human use, focusing on extended and controlled drug delivery, and are preparing for future clinical testing. The long-term goal is to incorporate this immune-activating implant directly into standard neurosurgical procedures for glioblastoma patients.

Related Links:
Massachusetts General Hospital
Harvard Medical School