Patient description: A 22-year-old Caucasian man came to the Clinic with a history of tremors since a year ago. The tremor was first in his right hand while holding something. Later the tremor became continuous and extended to both hands and legs and even at rest. The Kayser-Fleischer' ring was detected in the ophthalmologic exam. The physical exam revealed jaundice, hepatosplenomegaly and hypotonia of the upper limbs. He had a constant smile on his face, however, he has aggressive behavior according to his parents' explanation. His laboratory study was significant for a low serum caeruloplasmin (0.05 g/l), and a raised 24 hour urine copper excretion (120 μg/24 h). Wilson disease was confirmed by high liver copper concentration (305 μg/g dry weight of liver).

Clinical trial eligibility criteria: eligible ages (years): 18.0-75.0,  Wilson Disease Patient is able to provide, and has provided, written informed consent 2. Written documentation has been obtained in accordance with the relevant country and local privacy requirements, where applicable, including: For US sites: Authorization for Use and Release of Health Research Study Information and for EU sites: Data Protection Consent 3. Male or female, aged ≥ 18 and ≤ 75 years of age at time of consent 4. Patient has a diagnosis of Wilson's disease, as defined by a prior or current Leipzig score of ≥ 4 5. Patient's Wilson's disease is clinically stable, in the opinion of the investigator, and being treated with penicillamine for at least 1 year (52 weeks) prior to the screening/enrolment visit 6. Patient is on a stable dose and regimen of penicillamine for at least 4 months (16 weeks) prior to the screening/enrolment visit (other prescribed treatments for Wilson's disease not permitted during this study) 7. No anticipated need that patient will require additional pharmacological therapies other than study medication, including prescribed zinc therapy, for the management of copper levels during the study 8. Patient must be willing to maintain stable diet throughout the study, and avoid foods with high copper content, including the Penicillamine Baseline Period 9. Patient considered suitable to receive therapy with both TETA 4HCl and penicillamine administered twice a day 10. Negative central laboratory tests for HIV and viral hepatitis (results will be available after start of run-in period) 11. For female patients of childbearing potential, negative urine pregnancy test (at screening/enrolment visit and prior to randomization) 12. For females of childbearing potential, use of a reliable form of contraceptive 13. Patient is considered as able to complete study requirements and attend the study visits, in the opinion of the investigator Additional following receipt of Screening laboratory results 14. Patient is adequately controlled and tolerating penicillamine therapy as defined by fulfilment of all of the following: a. Serum non-ceruloplasmin bound copper (NCC) level between ≥ 25 and ≤ 150 μg/L* b. 24-hour urinary copper excretion of between ≥ 100 and ≤ 900 μg/24 hours* c. Alanine transaminase (ALT) < 2 times upper limit of normal* d. No other laboratory or clinical findings that would prevent continuation of maintenance therapy, in the opinion of the investigator * Based on results from screening/enrolment visit samples for which can be taken within ± 7 days of visit. Result should be within the assay limits of quantification for the sample. The ranges in μmol of copper are 0.40 to 2.38 μmol/L for NCC and 1.59 to 14.29 for 24-hour urinary copper excretion (using division by 63 of value in μg per Walshe, 2011). In the event that one or more of the above lab values fall outside the specified range, it can be repeated, including at the Week 4 and Week 8 visits. Additional at Week 12 visit (end of Penicillamine Baseline Period) and prior to randomization 15. Patient is adequately controlled and tolerating penicillamine therapy as defined by fulfilment of all of the following 1. Serum non-ceruloplasmin bound copper (NCC) level between ≥ 25 and ≤ 150 μg/L* 2. 24-hour urinary copper excretion of between ≥ 100 and ≤ 900 μg/24 hours** 3. Alanine transaminase (ALT) < 2 times upper limit of normal* 4. No other laboratory or clinical findings that would prevent continuation of maintenance therapy, in the opinion of the investigator Based on lab values from Week 8 visit; ** Based on lab value from Week 4 visit as routinely not performed at Week 8 visit, however can also be based on value at Week 8 visit if a repeat (unscheduled) urinary copper excretion was performed at this visit. Result should be within the assay limits of quantification for the sample. The ranges in μmol of copper are 0.40 to 2.38 μmol/L for NCC and 1.59 to 14.29 for 24-hour urinary copper excretion (using division by 63 of value in μg per Walshe, 2011). In the event that one or more of the above lab values fall outside the specified range, it can be repeated. The repeat value(s) must be available prior to randomization at Week 12 and, if within specified range, the patient can continue to randomization. If a patient fails this additional criterion at the end of the Penicillamine Baseline Period, the patient can return to the start of the run-in period i.e. Day 1 (but only once). A negative urinary pregnancy test is also required prior to randomization for females of childbearing potential  Patient is in 'de-coppering' phase of treatment for Wilson's disease, in the opinion of the investigator 2. Patient evidence of uncontrolled liver disease, including but not limited to: 1. Modified Nazer score of > 4 (result may not be available until after start of run in period since based on lab results*) 2. decompensated cirrhosis 3. acute hemolytic anemia 4. acute hepatitis 5. hepatic malignancy 6. evidence of acute liver failure 3. Cause of patient's liver disease is due to another condition, in the investigator's opinion 4. Patient has severe anemia defined as hemoglobin of ≤ 9 g/dL (result will be available after start of run-in period*) 5. Patient has experienced a gastrointestinal bleed within 6 months (24 weeks) prior to screening/enrolment visit 6. Patient has renal impairment defined as creatinine clearance of ≤ 30 mL/min (result may not be available until after start of run-in period*), or patient has nephritis or nephrotic syndrome, in the opinion of the investigator 7. Patient has neurological disease that prevents swallowing of study medication (e.g., requires a nasogastric feeding tube) or requires intensive in-patient medical care 8. Patient is currently taking medication containing trientine for management of Wilson's disease or has taken it within 4 months (16 weeks) of screening/enrolment visit 9. Patient is currently receiving prescribed zinc therapy for management of Wilson's disease or has taken it within 4 months (16 weeks) of screening/enrolment visit 10. Patient is taking any of the following concomitant therapies: gold therapy, antimalarial therapy, cytotoxic drugs, oxyphenbutazone, phenyl butazone 11. Patient has a known intolerance, allergy or sensitivity to penicillamine (that is uncontrolled) or to TETA 4HCl, including any component of the study medication 12. For female patients of childbearing potential, planning a pregnancy during study period or currently nursing 13. For female patients of childbearing potential, unable or unwilling to use a reliable form of contraceptive throughout the study 14. Patient is currently participating in another therapeutic study, or has previously participated in a therapeutic study within 30 days of screening/enrolment visit (or longer, if local requirements specify this) 15. Patient has any condition or in any situation which, in the investigator's opinion, puts the patient at significant risk, could confound study results, or may interfere significantly with the patient's participation in the study