Phase I study of copper-binding agent ATN-224 in patients with advanced solid tumors

SA Lowndes, A Adams, A Timms, N Fisher… - Clinical Cancer …, 2008 - AACR
SA Lowndes, A Adams, A Timms, N Fisher, J Smythe, SM Watt, S Joel, F Donate, C Hayward…
Clinical Cancer Research, 2008AACR
Purpose: Copper chelation reduces the secretion of many angiogenic factors and reduces
tumor growth and microvascular density in animal models. ATN-224 is a second-generation
analogue of ammonium tetrathiomolybdate. The aim of our phase I study was to reduce
serum copper levels, as measured by ceruloplasmin, to 5 to 15 mg/dL (normal 16-60) in 14
to 21 days, to determine the pharmacokinetic profile of ATN-224 and to evaluate dose-
limiting toxicities. Patients and Methods: Cohorts of patients were treated with escalating oral …
Abstract
Purpose: Copper chelation reduces the secretion of many angiogenic factors and reduces tumor growth and microvascular density in animal models. ATN-224 is a second-generation analogue of ammonium tetrathiomolybdate. The aim of our phase I study was to reduce serum copper levels, as measured by ceruloplasmin, to 5 to 15 mg/dL (normal 16-60) in 14 to 21 days, to determine the pharmacokinetic profile of ATN-224 and to evaluate dose-limiting toxicities.
Patients and Methods: Cohorts of patients were treated with escalating oral doses of ATN-224 until copper depletion followed by a titrated maintenance dose.
Results: Eighteen patients received 78 cycles of ATN-224. Mean baseline ceruloplasmin was 39.6 mg/dL. The maximum administered dose was 330 mg/d where grade 3 fatigue was dose-limiting. At the maximum tolerated dose of 300 mg/d, the median time to achieve target ceruloplasmin was 21 days, and toxicities included grade 3 anemia, grade 3 neutropenia, fatigue, and sulfur eructation. ATN-224 treatment caused a significant reduction (>90%) in RBC superoxide dismutase 1 activity and circulating endothelial cells. Pharmacokinetic data indicate greater absorption of ATN-224 and more rapid ceruloplasmin reduction when administered with a proton pump inhibitor. Stable disease of >6 months was observed in 2 patients.
Conclusions: Oral ATN-224 is a well-tolerated therapy and at a loading dose of 300 mg/d leads to a reduction of serum ceruloplasmin levels in 80% patients within 21 days. A loading dose of 300 mg/d for 2 weeks followed by a titrated maintenance dose will be the recommended starting dose for phase II study.
AACR