Background: The primary objective of this study was to assess safety and tolerability of single agent monoclonal anti-GD2 antibody ch14.18/CHO continuous long-term-infusion (LTI) in Japanese neuroblastoma patients. Secondary objectives were to evaluate pharmacokinetic (PK) and pharmacodynamics (PD) parameters and anti-tumor activity in patients with evaluable diseases.
Methods: Continuous infusion of 100 mg/m2/cycle (3.3mg/kg/cycle if body weight ≤12 kg) ch14.18/CHO was administered over 10 consecutive days every 5 weeks. Patients could receive up to five cycles. Blood samples were collected for assessment of PK, HACA response, immunophenotype, ADCC, CDC, biochemistry, Fc gamma receptor polymorphism, and MRD assessment.
Results: Ten patients with recurrent/refractory neuroblastoma were enrolled between September 2014 and July 2015. Nine patients (5 boys and 4 girls) were eligible and evaluable for toxicity and response assessments in this study. The median age was 4 (range 2-9) years old. Grade 3 or higher toxicities included anemia, leukopenia, neutropenia, elevation of hepatic transaminases, hyponatremia, and urticalia, but all these toxicities were reversible until the next scheduled cycle. The supportive care guidelines allowed all patients to continue the treatment at the same dose level. No unexpected Grade 4 toxicities were observed. PK parameters of ch14.18/CHO in Japanese patients were not different from Caucasian patients. All evaluable patients revealed an increased ADCC response over base line against neuroblastoma cells. Three of nine patients had partial responses evaluated by MIBG scans or tumor marker analysis. One patient discontinued after 2 cycles because of progressive disease in central nervous system. Eight patients are alive with stable disease without further chemotherapy (median follow-up 10 months from enrollment; range 7-17).
Conclusion: Japanese patients receiving ch14.18/CHO for high risk neuroblastoma had similar PK, tolerability and objective response rate compared to Caucasian patients. These results bridge data of ch14.18/CHO between Asian and Caucasian patients.