Safety, tolerability, and tumor response of IL4-Pseudomonas exotoxin (NBI-3001) in patients with recurrent malignant glioma

Purpose: This was an open-label, dose-escalation trial of intratumoral administration of IL-4Pseudomonas exotoxin (NBI-3001) in patients with recurrent malignant glioma. Patients and methods: A total of 31 patients with histologically verified supratentorial grades 3 and 4 astrocytoma were studied. Of these, 25 patients were diagnosed with glioblastoma multiforme (GBM) while six were diagnosed with anaplastic astrocytoma. Patients were over 18 years of age and had Karnofsky performance scores ≥60. Patients were assigned to one of four dose groups in a dose-escalation fashion: 6 µg/ml × 40 ml, 9 µg/ml × 40 ml, 15 µg/ml × 40 ml, or 9 µg/ml × 100 ml of NBI-3001 administered via convection-enhanced delivery intratumorally using stereotactically placed catheters. Patients were followed with serial MRI scans and clinical assessments every four weeks for the first 16 weeks and then every eight weeks until week 26. Results: No drug-related systemic toxicity, as evident by lack of hematological or serum chemical changes, was apparent in any patients; treatment-related adverse effects were limited to the central nervous system. No deaths were attributable to treatment. Drug-related grade 3 or 4 toxicity was seen in 39% of patients in all dose groups and 22% of patients at the maximum tolerated dose of 6 µg/ml × 40 ml. The overall median survival was 8.2 months with a median survival of 5.8 months for the GBM patients. Six-month survival was 52% and 48%, respectively. Gadolinium-enhanced magnetic resonance imaging of the brain showed areas of decreased signal intensity within the tumor consistent with tumor necrosis following treatment in many patients. Conclusions: NBI-3001 appears to have an acceptable safety and toxicity profile when administered intratumorally in patients with recurrent malignant glioma.