The open-label, single-arm Phase 2 trial enrolled nine Wilson disease patients across two centers in the UK and New Zealand. Patients were placed on a controlled copper diet with all intake and output measured during a baseline period, followed by daily dosing of ALXN1840 over multiple weeks to assess changes in copper balance.

ALXN1840 produced a cumulative mean decrease in copper balance of 6.08 mg over 21 days (95% CI -10.18 to -1.98 mg) with a mean daily reduction of 0.37 mg (p=0.005). The therapy also increased the fecal copper output-to-intake ratio by approximately 50% (p=0.041) and triggered immediate increases in plasma total copper and non-ceruloplasmin-bound copper, indicating effective copper mobilization via albumin tripartite complexes.

Treatment with ALXN1840 was generally well tolerated, with no serious adverse events reported. Notably, these improvements occurred in patients who had a mean of 16 years of prior standard-of-care treatment, demonstrating ALXN1840’s ability to mobilize and eliminate residual copper despite long-term therapy.