CTNI-41. INITIAL RESULTS OF A PHASE I WINDOW OF OPPORTUNITY TRIAL EVALUATING A FIRST-IN-CLASS CD29 INHIBITOR, OS2966, IN RECURRENT HIGH-GRADE GLIOMA

BACKGROUND OS2966 is a first-in-class, humanized and deimmunized monoclonal antibody which antagonizes CD29/β1integrin, a mechanosignaling receptor prominently upregulated in glioblastoma. Preclinical studies in mice and non-human primates have demonstrated safety and encouraging efficacy. A two-part, ascending concentration, phase I clinical trial was therefore initiated to evaluate the safety and feasibility of delivering OS2966 directly to the site of disease via convection-enhanced delivery (CED) in recurrent high-grade glioma patients. METHODS This study has a 2-part design: In part 1, patients undergo stereotactic tumor biopsy followed by placement of a multiport CED catheter for delivery of OS2966 to the bulk contrast enhancing tumor. Subsequently, patients undergo a clinically-indicated tumor resection followed by placement of two CED catheters and delivery of OS2966 to the surrounding tumor-infiltrated brain. A unique concentration-based accelerated titration design is utilized for dose escalation. Given availability of pre and post infusion samples, pharmacodynamic data will be analyzed to explore mechanism of action of OS2966. RESULTS Two subjects have been treated at two corresponding dose levels (0.2mg/mL and 0.4 mg/mL). No dose-limiting toxicity or unexpected safety issues have been identified. To date, reported adverse events were mild (i.e., grade 1) and consistent with underlying disease and surgical procedures. No adverse events were attributed to OS2966 or CED catheter placement. Further, no clinically significant changes from baseline neurological exam have been noted for either patient through initial follow-up. Maximal tumor coverage and concomitant gross total resection were achieved for both patients. Tumor volume measured 1.63 cm3 and 16 cm3 for Patient 1 and 2 respectively with an intratumoral Vd/Vi ratio of 1.3. and 0.94. Pharmacodynamic analysis via tissue-level biomarkers is ongoing and will be presented. CONCLUSION Initial data demonstrates the safety and feasibility of direct intracranial delivery of OS2966.