Treatment of Wilson's disease with tetrathiomolybdate: V. Control of free copper by tetrathiomolybdate and a comparison with trientine.

It has become clear that serum "free" copper (the copper not bound to ceruloplasmin in the blood) is the copper causing copper toxicity in Wilson's disease. But up until now, free copper has not been closely followed during initiation of anticopper therapy in neurologically presenting patients. During this period of initial therapy, the future fate of these patients hangs in the balance-if they worsen neurologically as often happens with penicillamine or trientine therapy, many never recover. We hypothesize that free copper levels are a biological marker of clinical outcome in these patients. In this article, we evaluate the control of free copper in 3 studies of initial anticopper treatment in neurologically presenting Wilson's disease patients. The first (study 1) is a 55-patient open-label trial of tetrathiomolybdate, the second (study 2) is a 48-patient double-blind trial comparing tetrathiomolybdate and trientine, and the third (study 3) is a 40-patient double-blind comparison of 2 disease regimens of tetrathiomolybdate. Free copper levels were determined by subtracting ceruloplasmin and tetrathiomolybdate bound copper from total serum copper. Tetrathiomolybdate showed very strong control of free copper levels over the 8 weeks of treatment in the 55-patient open-label study (study 1), reducing it to a mean value of about one fourth, or less, of baseline. In the tetrathiomolybdate/trientine double blind (study 2), tetrathiomolybdate again showed good control of free copper levels over 8 weeks of treatment, which is significantly better than trientine. In the trientine arm of study 2, mean free copper levels actually went up during trientine therapy. The 5 patients who neurologically worsened on trientine therapy over 8 weeks of treatment showed significant spikes in serum free copper levels associated in time with their neurologic worsening. Patients who did not worsen neurologically generally did not show significant spikes in free copper. Tetrathiomolybdate controlled copper less well in the dose regimen study (study 3) than in the previous 2 studies of tetrathiomolybdate treatment, probably because of a change in the way "away from food" tetrathiomolybdate was given.

Treatment of Wilson disease with ammonium tetrathiomolybdate: IV. Comparison of tetrathiomolybdate and trientine in a double-blind study of treatment of the neurologic presentation of Wilson disease.

OBJECTIVE: To compare tetrathiomolybdate and trientine in treating patients with the neurologic presentation of Wilson disease for the frequency of neurologic worsening, adverse effects, and degree of neurologic recovery. DESIGN: A randomized, double-blind, controlled, 2-arm study of 48 patients with the neurologic presentation of Wilson disease. Patients either received 500 mg of trientine hydrochloride 2 times per day or 20 mg of tetrathiomolybdate 3 times per day with meals and 20 mg 3 times per day between meals for 8 weeks. All patients received 50 mg of zinc 2 times per day. Patients were hospitalized for 8 weeks, with neurologic and speech function assessed weekly; discharged taking 50 mg of zinc 3 times per day, and returned annually for follow-up. SETTING: A university hospital referral setting. PATIENTS: Primarily newly diagnosed patients with Wilson disease presenting with neurologic symptoms who had not been treated longer than 4 weeks with an anticopper drug. INTERVENTION: Treatment with either trientine plus zinc or tetrathiomolybdate plus zinc. MAIN OUTCOME MEASURES: Neurologic function was assessed by semiquantitative neurologic and speech examinations. Drug adverse events were evaluated by blood cell counts and biochemical measures. RESULTS: Six of 23 patients in the trientine arm and 1 of 25 patients in the tetrathiomolybdate arm underwent neurologic deterioration (P<.05). Three patients receiving tetrathiomolybdate had adverse effects of anemia and/or leukopenia, and 4 had further transaminase elevations. One patient receiving trientine had an adverse effect of anemia. Four patients receiving trientine died during follow-up, 3 having shown initial neurologic deterioration. Neurologic and speech recovery during a 3-year follow-up period were quite good. CONCLUSION: Tetrathiomolybdate is a better choice than trientine for preserving neurologic function in patients who present with neurologic disease.

Treatment of Wilson disease with ammonium tetrathiomolybdate: III. Initial therapy in a total of 55 neurologically affected patients and follow-up with zinc therapy.

BACKGROUND: It is unclear what anticopper drug to use for patients with Wilson disease who present with neurologic manifestations because penicillamine often makes them neurologically worse and zinc is slow acting. OBJECTIVE: To evaluate the frequency of neurologic worsening and drug adverse effects with ammonium tetrathiomolybdate. DESIGN: Open-label study of 55 untreated patients (22 of them new) presenting with neurologic Wilson disease treated with tetrathiomolybdate varying from 120 to 410 mg/d for 8 weeks and then followed up for 3 years. Neurologic function was assessed with scored neurologic and speech tests. SETTING: A university hospital referral setting. PATIENTS: All untreated, newly diagnosed patients with neurologic Wilson disease. INTERVENTION: Treatment with tetrathiomolybdate. MAIN OUTCOME MEASURES: Neurologic function was evaluated by neurologic and speech examinations. Drug adverse effects were evaluated by complete blood cell counts and biochemical measures. RESULTS: Only 2 (4%) of 55 patients treated with tetrathiomolybdate showed neurologic deterioration, compared with an estimated 50% of penicillamine-treated patients. Five of the 22 new patients exhibited bone marrow suppression and 3 had aminotransferase elevations. These numbers are higher than in the original 33 patients and appear to be due primarily to a more rapid dose escalation. CONCLUSIONS: Tetrathiomolybdate shows excellent efficacy in patients with Wilson disease who present with neurologic manifestations. With rapid escalation of dose, adverse effects from bone marrow suppression or aminotransferase elevations can occur.