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2065 Background: Copper chelation reduces the secretion of many angiogenic factors and reduces tumour growth and microvascular density in animal models. ATN-224 is a second generation analogue of ammonium tetrathiomolybdate, which reportedly can stabilise disease but was limited by the slow onset of copper depletion (50-60 days). Preclinical studies suggest ATN-224 may act primarily by superoxide dismutase 1 (SOD-1) inhibition. The aim of our phase I study was to reduce serum copper levels, as measured by ceruloplasmin (Cp), to 5-15 mg/dl (normal 16-60) in 14-21 days, to determine the pharmacokinetic profile, and to evaluate dose-limiting toxicities. METHODS: Cohorts of pts were treated with escalating doses of ATN-224, twice daily, until copper depletion, followed by a titrated maintenance dose. Serum Cp was used as a surrogate marker of copper levels and was titrated to a target range of 5-15mg/dL (normal 16-60). RESULTS: 18 pts have received 54 cycles of ATN-224. Tumours were breast (4), renal (2), melanoma (2), colon (2), and a variety of other types (1 each). Pts received ATN 224 loading doses in cohorts of 1 to 6 pts: 150 (1), 210 (2), 240 (1), 270 (6), 300 (5), and 330 mg/day (3). Mean age was 56 yrs (range 37-78) and PS 0-2. Mean baseline Cp was 39.6 (range 22-63 mg/dL). The maximum administered dose was 330 mg/day where grade 3 lethargy was observed in 3 pts. Of the 4 pts at the maximum tolerated dose of 300 mg/day who have currently completed the loading schedule, all 4 have achieved a reduction of Cp to within 10% of the target range within 21 days. Other toxicities at this dose level included sulphur burps (Gr 1), vomiting (Gr 2), neutropenia (Gr 2), and anaemia (Gr 3). Toxicities reduced in the second and subsequent cycles when doses were titrated downward to maintain Cp levels in target range. PK data indicate greater absorption of ATN 224 and more rapid reduction in Cp with concurrent administration of a proton pump inhibitor. Stable disease of >6 months was observed in 4 pts. CONCLUSIONS: Oral ATN-224 is a well-tolerated therapy and at a loading dose of 300 mg/day leads to a reduction of serum Cp levels to 20% normal within 21 days. This will be the recommended starting dose level for phase II study. (Sponsored by Cancer Research UK; funded by Attenuon, LLC). [Table: see text].

Type

Journal article

Journal

J Clin Oncol

Publication Date

20/06/2006

Volume

24