Phase I Trial of Oral Yeast-Derived β-Glucan to Enhance Anti-GD2 Immunotherapy of Resistant High-Risk Neuroblastoma

SIMPLE SUMMARY: Beta glucans, complex polysaccharides, can prime leukocyte dectin-1 and CR3-receptors and enhance anti-tumor cytotoxicity of monoclonal antibodies. In a phase I study (clinicaltrials.gov NCT00492167), we treated patients with intravenous 3F8 (fixed dose of 10 mg/m(2)/day × 10 days) and oral BG (dose-escalated from 10–200 mg/kg/day × 17 days in cohorts of 3–6 patients each). Forty-four patients completed 141 cycles of therapy with 3F8 + BG. One patient developed DLT: transient self-limiting hepatic transaminase elevation at a BG dose of 120 mg/kg/day. Overall, 1, 3, 12 and 24 evaluable patients had complete response, partial response, stable and progressive disease, respectively, at the end of treatment. Positive human anti-mouse antibody response and dectin-1 rs3901533 polymorphism were associated with better overall survival. BG dose level and serum BG levels did not correlate with response. BG lacked major toxicity and, in combination with 3F8, demonstrated anti-neuroblastoma activity against resistant disease. The recommended phase II dose was established at 40 mg/kg/day. ABSTRACT: Beta glucans, complex polysaccharides, prime leukocyte dectin-1 and CR3-receptors and enhance anti-tumor cytotoxicity of complement-activating monoclonal antibodies. We conducted a phase I study (clinicaltrials.gov NCT00492167) to determine the safety of the combination of yeast-derived beta glucan (BG) and anti-GD2 murine monoclonal antibody 3F8 in patients with relapsed or refractory high-risk neuroblastoma. Patients received intravenous 3F8 (fixed dose of 10 mg/m(2)/day × 10 days) and oral BG (dose-escalated from 10–200 mg/kg/day × 17 days in cohorts of 3–6 patients each). Forty-four patients completed 141 cycles. One patient developed DLT: transient self-limiting hepatic transaminase elevation 5 days after starting BG (120 mg/kg/day). Overall, 1, 3, 12 and 24 evaluable patients had complete response, partial response, stable and progressive disease, respectively, at the end of treatment. Positive human anti-mouse antibody response and dectin-1 rs3901533 polymorphism were associated with better overall survival. BG dose level and serum BG levels did not correlate with response. Progression-free and overall survival at 2 years were 28% and 61%, respectively. BG lacked major toxicity. Treatment with 3F8 plus BG was associated with anti-neuroblastoma responses in patients with resistant disease. Although the maximal tolerated dose for yeast BG was not reached, considering the large volume of oral BG, we recommended 40 mg/kg/day as the phase II dose.