3080 Background: O is a vascular-disrupting agent derived from combretastatin A4-phosphate that induces rapid but transient tumor vascular shutdown. In experimental models, the combination of O with VEGF-blockade induced more regressions than O alone. This phase I study was performed to determine the maximum tolerated dose (MTD), and assess the overall safety, pharmacokinetics (PK), pharmacodynamics (PD) and preliminary antitumor activity of O plus B. Trial is funded by sanofi. Methods: Patients (pt) with advanced solid tumors, ECOG PS ≤1, and adequate organ function were eligible. Increasing doses of O (mg/m²) was administered intravenously (IV) on day (d) 1; B (5 or 10mg/kg) was administered IV on d2, in 21d cycles (C). A Bayesian design was applied to determine dose escalation steps and MTD. PK sampling was performed in C1 and C2. PD sampling for circulating endothelial cells (CEC) and progenitors (CEP) were performed throughout. Dynamic contrast-enhanced ultrasound (DCE-US) to assess tumor perfusion was performed before and after C1 and C2 dosing. Results: 25 pts (M:F 6:19; median age 49 years [range 27-75]) have been treated at 8 dose levels of O/B: 8/5 (3), 11.5/5 (4), 11.5/10 (3), 15.5/10 (3), 20/10 (3), 25/10 (3); 35/10 (3) and 42/10 (3). Ovarian cancer was the most frequent tumor type (n=11). Median Cs received was 3 (1 to 14). No DLTs were observed during C1. Drug-related grade (g) 3-4 adverse events (AE) included hypertension in 2 pts (8/5; 11.5/5) and ileal perforation in 1 pt with peritoneal carcinomatosis at laparotomy (11.5/10). A case of duodenal perforation was unlikely related (25/10). Two pts with ovarian cancer (11.5/5; 20/10) had confirmed partial responses (4.4 months (mo) and 7+ mo). 13/23 (57%) pts with ≥ 1 tumor assessment had stable disease (n=8; median 4.3 mo [1.8-9.5]; 5 ongoing). Data from cohorts 1 and 2 demonstrated no evidence of a PK interaction.17/25 patients demonstrated a peak in CEC, and 7/9 patients a peak in CEP. 4/7 DCE-US evaluable pts had >50% drop in tumor perfusion (AUC) at Day 8 of C1. Conclusions: O combined with B is well tolerated with early evidence of clinical activity. The MTD has not been reached (current dose level 50/10); cohorts of O combined with B at 15 mg/kg will be tested.
Phase I Study of Ombrabulin, a Vascular Disrupting Agent (VDA), Administered Every 3 Weeks to Japanese Patients with Advanced Solid Tumors
