Treatment of Wilson's disease with zinc: III. Prevention of reaccumulation of hepatic copper.

Twelve patients with Wilson's disease, most of whom had received intensive treatment with penicillamine, were given zinc therapy as their sole medication for copper control. Serial liver biopsies were performed during a 12- to 20-month follow-up period to determine whether hepatic copper reaccumulates during zinc therapy. Mean baseline liver copper concentration was 255 micrograms/gm dry weight, whereas the mean value after therapy was 239 micrograms. No patient demonstrated hepatic reaccumulation of copper during zinc therapy. Copper balance, 24-hour urinary copper excretion, and nonceruloplasmin plasma copper concentration all indicated good copper control during zinc therapy. Hepatic zinc concentration increased twofold to threefold over baseline values but no toxicity was seen. Hepatic zinc concentrations appeared to reach a plateau after 12 to 18 months of zinc therapy. We conclude that oral zinc as the sole maintenance therapy in patients with Wilson's disease prevents hepatic reaccumulation of copper.