A phase I pharmacokinetic (PK) and pharmacodynamic (PD) study of MN-029, a novel vascular disrupting agent (VDA), in patients (pts) with advanced solid tumors

Abstract

3096 Background: MN-029 is a novel VDA that binds reversibly to the colchicine-binding site on tubulin and inhibits microtubule assembly, resulting in disruption of the cytoskeleton of tumor endothelial cells (EC). Disruption of the tumor EC cytoskeleton ultimately leads to a temporary reduction in tumor blood flow. Methods: MN-029 is administered IV as a 10–20 min infusion, at 3-wk intervals in pts with advanced cancer. The study has followed an accelerated titration design, with intrapatient dose escalation. PD effects on tumor blood flow are evaluated using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Results: 28 pts were enrolled (13M/15F), median age 56 (range 35 - 76) and tumor types: colorectal (5), renal (5), hepatocellular (3), ovarian (2), melanoma (2), soft tissue sarcoma (2), carcinoid (2) and others (7). A total of 110 cycles of MN-029 were given, median 3/pt (range 1–20), over 9 dose levels (4, 8, 16, 24, 36, 54, 80, 120 and 180 mg/m2). Escalation proceeded until an initial dose-limiting toxicity (DLT) was observed in 1 pt in the 180 mg/m2 cohort, consisting of a reversible episode (3 hours post dose) of acute coronary ischemia (without sequelae and with preservation of myocardial function) probably due to coronary vasospasm. Therefore, this cohort was expanded to 6 pts, with no further DLTs observed. Common mild to moderate toxicities included nausea, vomiting (which appears dose-related), hypotension, fatigue and diarrhea. There was no significant myelotoxicity, stomatitis or alopecia. Seven pts had stable disease after 3 cycles, including 2 pts with carcinoid tumor (+21 cycles and +17 cycles). PK data generally indicated dose-related increases in Cmax and AUC values, although substantial inter-patient variability was observed. Tumor blood flow reduction assessed by DCE-MRI was recorded at 120 and 180 mg/m2, but not at 80 mg/m2. Conclusions: MN-029 produced reductions in tumor blood flow at doses that were well tolerated. Accrual continues at 225 mg/m2. [Supported in part by grants from MediciNova, Inc. and M01 RR-000080] [Table: see text]