Decentralized study to assess patient reported treatment satisfaction comparing their current standard-of-care Wilson's Disease (WD) treatment with a new once-daily Trientine (TETA) 4HCl formulation.

This is a single arm study where patients on Standard of Care maintenance therapy with a prescribed approved Wilson's Disease therapy administered at least twice daily will be screened for eligibility by the clinical research site either following referral from a participant identification centre (PIC) or following advertisements. An initial screening Patient Reported Outcome (PRO) assessment including the Treatment Satisfaction Questionnaire for Medication-9 (TSQM-9) and Morisky Medication Adherence Scale-8 (MMAS-8) will also be collected.

Patients who meet all the study entry criteria will be switched to a new TETA 4HCl formulation for 28 days and will be monitored using Patient Reported Outcomes and specific posology questions held within a patient questionnaire pack and blood investigations. During this treatment phase (between Day 14 and Day 28 of dosing), each participant will be interviewed to collect qualitative data on disease and therapy. Patients will then be returned to their Standard of Care treatment and followed for a further 28 days continuing to be assessed using Patient Reported Outcomes and repeat blood investigations. The safety period will be finalised with an End of Study Assessment.

Inclusion Criteria:

1. Willing and able to give informed consent for participation in the study.
2. Proficient and fluent in English language speaker, writer and reader.
3. Patients of any gender, aged 18 years or older as of signing the Informed Consent Form (ICF).
4. Patients on current SOC WD maintenance treatment prescribed twice daily (or more frequently) and dose has been unchanged for at least 3-months.
5. Women of childbearing potential and sexually active males must agree to adhere to a contraceptive method.

Exclusion Criteria:

1. Major systemic disease or other illness that would, in the opinion of the investigator, compromise patient safety or interfere with the collection or interpretation of the study results.
2. Patients with severe anaemia (e.g., Haemoglobin <10 g/dL).
3. Female participants who are pregnant (including a positive pregnancy test at Screening and on Day-1) or breastfeeding.
4. Any contraindications as described in the current Investigator Brochure for TETA 4HCl.
5. Subject receiving total daily dose of chelator as SOC greater or equal to 1200mg (trientine base or d-penicillamine).
6. In the opinion of the investigator, the patient is likely to be a non-attender or uncooperative for routine clinical visits during the study.