DDEL-12. A CONFORMABLE IMPLANTABLE DEVICE - MICROMESH - FOR THE SUSTAINED DELIVERY OF CHEMOTHERAPEUTIC MOLECULES AND IMMUNE CHECK POINT INHIBITORS AGAINST HIGH-GRADE GLIOMAS

Abstract

Abstract High-grade gliomas, like glioblastoma (GBM), continue to have a poor prognosis with therapeutic options limited to maximal safe resection and adjuvant radiochemotherapy. Effective treatment is hampered by the blood-brain barrier, limiting the intratumor permeation of systemically administered agents; and biological heterogeneity of malignant cells, requiring complex therapeutic regimens. A conformable, compartmentalized polymeric implant – microMESH – has been engineered to overcome these obstacles by realizing a localized, sustained release of drugs, small inhibitors, antibodies, and nanomedicines. In the present configuration, microMESH comprises a water-soluble polyvinyl alcohol microlayer, loaded with the immune checkpoint aCD47, intercalated with a microfabricated network of poly lactic-co-glycolic acid, carrying docetaxel (DTXL). Upon deposition over the tumor margins, microMESH adheres and conforms to the local tissue releasing thereof its therapeutic cargo for several weeks, circumventing possible systemic toxicity. Gel permeation chromatography, nuclear magnetic resonance spectroscopy, weight and pH variations were measured to assess the microMESH biodegradation over time. microMESH biocompatibility and cytotoxicity were assessed on cancer cell monolayers and spheroids. The preclinical performance of microMESH was evaluated in two syngeneic mouse models of high-grade gliomas obtained via the intracranial inoculation of murine cancer cells – CT-2A, cold tumor; GL261, hot tumor. Flow cytometry was used to map the immune component in the tumor and assess the expression of immune checkpoints. Bioluminescence imaging was used to monitor tumor proliferation longitudinally. microMESH biodegraded in ~2 months with no documented toxicity. Preliminary experiments with an aCD47/DTXL–microMESH applied over the unresected margins of an orthotopic CT-2A model documented a median overall survival of 33.5 days against 18 days for untreated mice, 22 days for intravenously injected DTXL, 24 days for intraperitoneally administered aCD47 (statistically not significant difference among the control groups). microMESH allowed the sustained delivery of complex combination therapies directly at the tumor bed demonstrating superior efficacy over systemic therapies.