Final clinical and pharmacokinetic (PK) results from a phase 1 study of the novel N-cadherin (N-cad) antagonist, Exherin (ADH-1), in patients with refractory solid tumors stratified according to N-cad expression

Abstract

3016 Background: Malignant transformation and invasiveness correlate with upregulation of N-cad, a cell adhesion molecule expressed on tumor cells and vascular endothelium. N-cad antagonism by ADH-1, a cyclic pentapeptide (CHAVC), causes rapid tumor vascular disruption and apoptosis in preclinical models. We report the final clinical and PK results from the first human study (AHX-01–001). Methods: 46 subjects with incurable solid tumors stratified according to tumor N-cad expression were enrolled. 99 doses of ADH-1 were given by IV bolus or short infusion (31 in a Special Access Program). Doses ranged from 50–1000 mg/m2, with 3–6 subjects/cohort. Blood and urine were collected for PK on Day 1, assayed by LC/MS/MS, and a 2 compartment analysis was performed. Results: ADH-1 was generally well tolerated and the maximum tolerated dose was not defined. The most commonly reported adverse events were grade 1–2 fatigue (59%), nausea (32%), dysgeusia (25%), and flushing (20%). 4 subjects in the N-cad positive group (n=28, including 3 N-cad unknown) demonstrated anti-tumor activity; a PR of 6 month duration in refractory esophageal carcinoma; a minor response in lung metastases from an unknown primary following a single dose; and >7 months SD in refractory adrenocortical and colorectal carcinoma. No anti-tumor activity was noted in the N-cad negative group (n=18). The mean initial ADH-1 half-life (t½) was 20 min and the mean terminal phase t½ was 2.2 hr. Mean systemic clearance (CL) was 6.5 L/hr/m2. Both t½ and CL were independent of dose. Cmax increased dose proportionally, ranging from 7 to148 μg/mL, and AUC0-∞ tended to increase dose proportionally. The volume of distribution at steady-state (Vss) averaged 14.3 L/m2, indicating modest tissue distribution. Approximately 30% of the dose was excreted unchanged in the urine. Conclusions: ADH-1 was generally well tolerated and demonstrated evidence of anti-tumor activity in subjects with N-cad positive tumors. The PK profile was biphasic and the t½ averaged 2.2 hr. Cmax and AUC0-∞ increased dose proportionally, and CL was independent of dose. No significant financial relationships to disclose.