CTIM-13. D2C7-IT IN COMBINATION WITH AN FC-ENGINEERED ANTI-HUMANCD40 MONOCLONAL ANTIBODY (2141-V11) ADMINISTERED INTRATUMORALLY VIA CONVECTION-ENHANCED DELIVERY (CED) FOLLOWED BY CERVICAL PERILYMPHATIC INJECTIONS (CPLIS) OF 2141-V11 IN PATIENTS WITH RECURRENT GLIOBLASTOMA (RGBM)

Abstract BACKGROUND The combination of D2C7-IT, an antibody toxin conjugate, and anti-mouseCD40 via CED generates robust antitumor immunity by killing tumor cells, activating microglia, reversing glioma-associated microglia and macrophage (GAMM)-mediated immune suppression, and empowering polyfunctional tumor antigen-specific CD8 T cells in glioma models. In addition to reprogramming GAMMs, anti-CD40 also activated dendritic cells and induced glioma-specific T cell responses in tumor draining lymph nodes. After establishing the phase 2 dose of the combination of D2C7-IT+2141-V11 when infused via CED, we initiated an assessment of the safety and efficacy of the combination of D2C7-IT+2141-V11 CED followed by repeated subcutaneous CPLIs of 2141-V11 ipsilateral to the tumor in patients with rGBM, IDH wild-type (NCT04547777). METHODS Eligible are adult patients with solitary supratentorial rGBM; ≥4weeks after chemotherapy, bevacizumab, or investigational agent; adequate organ function; and KPS ≥70%. Patients are treated with D2C7-IT (166μg) and 2141-V11 (3mg), both infused via CED, followed by CPLI of 2141-V11 at 2mg at weeks 2 and 4 post D2C7-IT+2141-V11 CED, followed by every 3 weeks for 1 year and then every 4-6 weeks. RESULTS As of May 22, 2024, 18 patients with rGBM (median age of 54) were treated with D2C7-IT+2141-V11 CED followed by CPLIs of 2141-V11. 83% patients remain alive (range 3.3-14.8 months from start of D2C7-IT CED infusion) with a median of 8 CPLIs of 2141-V11 received (range 3-19). No study related grade 4 or 5 adverse events (AEs) were observed. Grade 3 AEs related to D2C7-IT and/or 2141-V11 include one each of hydrocephalus, headache, seizure, and cerebral edema. AEs related exclusively to CPLIs of 2141-V11 consist of grade 1 injection site reaction (n=16). CONCLUSIONS The addition of CPLIs of 2141-V11 post CED of D2C7-IT+2141-V11 is feasible and has shown an acceptable toxicity profile. The safety and efficacy results will be updated.