1080 Background: Aminophospholipid are normally expressed on damaged or apoptotic cells, as well as on the intravascular surface of EC of vessels feeding the tumor as a result of the tumor microenvironment (e.g., hypoxia, reactive oxygen species). Bavituximab (B), a novel monoclonal antibody against PS, has demonstrated preclinical anti-tumor activity by eliciting both innate and adaptive immune responses specific to tumor vasculature. Here we report preliminary results of the phase I study in patients (pts) with advanced solid tumors. Methods: This is a phase I, dose escalation, safety, tolerability and pharmacokinetic (PK) study, as well as to define DLT, MTD and/or maximum effective dose (MED) in pts with advanced refractory cancers. Planned cohorts of 6 pts, each were to receive 0.1, 0.3, 1 or 3 mg/kg. Escalation was permitted if mean cohort Cmax ≤ 65 mcg/mL and dose limiting toxicities (DLT) was observed in ≤ 1 of 6 pts. No premedication was planned or needed. DLT was defined as ≥ grade 3 drug-related adverse events (AE), ≥ grade 2 PT, or ≥ grade 3 aPTT. B was given as a 90 minute IV infusion (on days 0, 28, 35, 42 for the first two dose cohorts and 0, 7, 14, 21 for the third- and fourth-dose cohorts. Although not a study endpoint, tumor response was collected at day 56. Results: Data are available for the first 20 pts enrolled (10 breast, 3 colorectal, 2 pancreatic, 1 each of hepatocellular carcinoma, head and neck, melanoma, mesothelioma, and prostate cancer). Cohorts by dose: 0.1 mg/kg (8 pts), 0.3 mg/kg (6pts), and 1 mg/kg (6pts). Median age was 59 years and 70% of pts were females. (Q: see attached Excel file). No DLTs or drug-related severe AEs were reported. Common drug-related AEs were fatigue (7pts), nausea (6 pts), dry skin (3 pts), constipation (2 pts) and dyspnea (2 pts). All AEs were grade 1 or 2 and no dose relationship was observed. PK was dose proportional with mean serum Cmax of 2.3, 5.2 and 16.6 mcg/mL for the 0.1, 0.3 and 1 mg/kg groups, respectively. No accumulation of B was seen after multiple weekly dosing. Conclusions: Single agent bavituximab is well tolerated to date, with a predictable PK profile. Accrual of the last planned cohort is underway. MTD has not been reached. Final results will be available for presentation at the time of the Meeting. [Table: see text]
Allogeneic clonal mesenchymal stem cell therapy for refractory graft-versus-host disease to standard treatment: a phase I study
