Galzin® is an oral prescription medicine commercialized by Teva Pharmaceuticals that is indicated for the maintenance treatment of patients with Wilson Disease who have been previously treated with a chelating drug.1 

Wilson disease is a rare autosomal recessive disorder of copper metabolism that is characterized by the accumulation of copper in several tissues with consequent toxicity. Copper accumulates in the liver and then is released into the bloodstream when the hepatocytes are no longer able to contain the excess copper. This copper later accumulates in other tissues such as the brain and the corneas.1-4 Clinical manifestations of this disease include hepatitis, chronic cirrhosis, liver failure, movement disorders, tremor, and psychiatric disorders.2

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Zinc Acetate Mechanism of Action and Usage

The treatment of Wilson disease relies on the reduction of excess copper and the subsequent prevention of its accumulation. Patients must restrict dietary copper and take chelating agents that help reduce toxicity and promote copper depletion. Following the stabilization of their symptoms, patients start maintenance therapy.1 

Galzin consists of zinc acetate, which induces the production of intestinal metallothionein. This forms a complex with copper, preventing its transfer into the bloodstream. Through this mechanism, zinc acetate inhibits the intestinal absorption of copper from the diet and the reabsorption of copper secreted internally from the saliva, bile, and gastric fluids.1,2,4 Although it is used mainly in asymptomatic patients, zinc acetate can also be used with copper chelators.2,5 

Galzin (Zinc Acetate)
Galzin (Zinc Acetate) Credit: PubChem

The recommended dose of zinc acetate for adults is 50 mg three times per day, and it should be taken on an empty stomach at least 1 hour before or 2 to 3 hours after a meal to avoid interference with drug uptake. Pediatric patients and pregnant women may be advised to take zinc acetate at a reduced dose of 25 mg three times daily.1

The administration of zinc acetate is linked to few side effects.2,4 Gastric irritation may occur, however, which can be alleviated with simultaneous protein consumption or proton pump inhibitors.4 Liver and pancreatic enzymes may be also elevated for weeks to months, which may suggest pancreatitis.4 Overtreatment is not a frequent issue until treatment has been administered for several years, and this can present as mild anemia or leukopenia.2

Galzin is not recommended for the initial treatment of symptomatic patients due to the delay in the induction of metallothionein to block copper absorption. Monitoring of patients while on zinc acetate therapy is done through 24-hour urine copper excretion and the assessment of signs and symptoms.1

Read more about Wilson disease therapies

Zinc Acetate in Clinical Studies

The approval of zinc acetate by the US Food and Drug Administration (FDA) in 1997 for maintenance therapy in patients with Wilson disease followed several studies.2

A single-center study enrolling 60 patients with Wilson disease was performed to evaluate various dose regimens of the drug. All tested regimens appeared better than receiving no treatment, though there was little experience with dosages other than 50 mg three times a day. Once-daily dosing was found to be unsatisfactory.1

In a long-term study involving 141 patients, the efficacy and toxicity of zinc acetate were evaluated with a follow-up of 1 to 10 years. Results of this study revealed that long-term efficacy was achieved in patients complying with the maintenance treatment. Additionally, this study included 30 presymptomatic patients who were treated with zinc acetate. Data showed that the drug was effective in preventing the onset of symptoms and improving both 24-hour urine copper excretion and nonceruloplasmin plasma copper levels.6

Studies have shown that pregnant women should maintain anticopper treatment during their pregnancies.2 A study involving 19 symptomatic and presymptomatic women who were treated with zinc acetate showed that the drug was relatively safe for the fetus.7 These women delivered 26 live-birth babies. All women were taking zinc acetate at the time of delivery.1,7

Other studies focusing on maintenance therapy with zinc acetate were performed, including with pediatric patients. However, more information is needed for patients under the age of 6 years.2,8

References

1. Galzin. Prescribing information. Teva Pharmaceuticals USA, Inc; 2021. Accessed September 14, 2022.

2. Brewer GJ. Zinc acetate for the treatment of Wilson’s disease. Expert Opin Pharmacother. 2001;2(9):1473-1477. doi:10.1517/14656566.2.9.1473

3. Wilson disease. National Organization for Rare Disorders (NORD). Accessed September 14, 2022.

4. Camarata MA, Ala A, Schilsky ML. Zinc maintenance therapy for Wilson disease: a comparison between zinc acetate and alternative zinc preparations. Hepatol Commun. 2019;3(8):1151-1158. doi:10.1002/hep4.1384

5. Treatment. Wilson Disease Association. Accessed September 14, 2022.

6. Brewer GJ, Dick RD, Johnson VD, Brunberg JA, Kluin KJ, Fink JK. Treatment of Wilson’s disease with zinc: XV long-term follow-up studies. J Lab Clin Med. 1998;132(4):264-278. doi:10.1016/s0022-2143(98)90039-7

7. Brewer GJ, Johnson VD, Dick RD, Hedera P, Fink JK, Kluin KJ. Treatment of Wilson’s disease with zinc. XVII: treatment during pregnancy. Hepatology. 2000;31(2):364-370. doi:10.1002/hep.510310216

8. Brewer GJ, Dick RD, Johnson VD, Fink JK, Kluin KJ, Daniels S. Treatment of Wilson’s disease with zinc XVI: treatment during the pediatric years. J Lab Clin Med. 2001;137(3):191-198. doi:10.1067/mlc.2001.113037

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