verubulin and Glioblastoma

Treatment options are limited for recurrent glioblastoma (GBM). Verubulin is a microtubule destabilizer and vascular disrupting agent that achieve high brain concentration relative to plasma in animals. Adults with recurrent GBM who failed prior standard therapy were eligible. The primary endpoint was 1-month progression-free survival (PFS-1) for bevacizumab refractory (Group 2) and 6-month progression-free survival (PFS-6) for bevacizumab naïve patients (Group 1). Verubulin was administered at 3.3 mg/m(2) as a 2-h intravenous infusion once weekly for 3 consecutive weeks in a 4-week cycle. The planned sample size was 34 subjects per cohort. 56 patients (37 men, 19 women) were enrolled, 31 in Group 1 and 25 in Group 2. The PFS-6 for Group 1 was 14% and the PFS-1 for Group 2 was 20%. Median survival from onset of treatment was 9.5 months in Group 1 and 3.4 months in Group 2. Best overall response was partial response (n = 3; 10% in Group 1; n = 1; 4.2% in Group 2) and stable disease (n = 7; 23% in Group 1; n = 5; 21% in Group 2). In Group 1, 38.7% of patients experienced a serious adverse event; however only 3.2% were potentially attributable to study drug. In Group 2, 44% of patients experienced a serious adverse event although none were attributable to study drug. Accrual was terminated early for futility. Single agent verubulin, in this dose and schedule, is well tolerated, associated with moderate but tolerable toxicity but has limited activity in either bevacizumab naïve or refractory recurrent GBM.

Topics: Adult; Aged; Angiogenesis Inhibitors; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Bevacizumab; Brain Neoplasms; Disease-Free Survival; Female; Glioblastoma; Humans; Male; Middle Aged; Neoplasm Recurrence, Local; Prospective Studies; Quinazolines; Treatment Outcome; Young Adult

Verubulin (MPC-6827) is a microtubule-destabilizing agent that achieves high concentrations in the brain. Verubulin disrupts newly formed blood vessels in xenografts. We determined the safety and tolerability of verubulin administered in combination with carboplatin in patients with relapsed glioblastoma multiforme (GBM). Three pre-selected doses of verubulin were tested: 2.1, 2.7, and 3.3 mg/m(2) in a standard "3+3" design. Verubulin was given every second week of a 6-week cycle in the 2.1 mg/m(2) cohort or weekly for 3 weeks of a 4-week cycle in subsequent cohorts. Carboplatin was administered intravenously at an area under the curve (AUC) dosage 4 every 2 weeks for the 2.1 mg/m(2) cohort or on day 1 of each 4-week cycle in subsequent cohorts. Nineteen patients with GBM in first or second relapse were enrolled. Four patients (21 %) experienced a grade 3 or greater verubulin- or carboplatin-related adverse event, including hypesthesia, cerebral ischemia, anemia, and thrombocytopenia. The mean plasma half life of verubulin was 3.2 h (SD = 0.82). Two patients achieved at least a partial response by Macdonald criteria. One of these patients remains progression free and off treatment more than 24 months beyond his initiation of verubulin. Five patients had stable disease. Median progression-free survival (PFS) across all patients was 8 weeks, and the 6-month PFS rate was 21 %. The combination of verubulin at the previously determined single-agent maximum tolerated dose of 3.3 mg/m(2) with carboplatin in patients with recurrent/refractory GBM is safe and well tolerated. In this patient population with a highly vascularized tumor, no cerebral hemorrhage was observed.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Carboplatin; Cohort Studies; Female; Glioblastoma; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Recurrence, Local; Prognosis; Quinazolines; Survival Rate; Tissue Distribution