TRADITiONAL Study: First-Line Trientine RCT Bets on Evidence Upgrade, But Once-Daily Formulation Remains Unproven

Orphalan Launches Phase III TRADITiONAL Trial for Wilson Disease

Orphalan has initiated the global Phase III TRADITiONAL Study, evaluating an investigational once-daily formulation of trientine tetrahydrochloride for Wilson disease, a rare genetic disorder of copper metabolism. This randomised, multi-centre, open-label trial will compare the efficacy and safety of the new regimen against D-penicillamine, a standard copper-chelating agent, as first-line therapy over 48 weeks. The study is recruiting symptomatic and asymptomatic patients aged eight and above, who are either new to Wilson disease therapies or have not previously received chelator treatment, with initial sites in the US and planned expansion to Saudi Arabia, China, and Pakistan. The goal is to simplify treatment burden and improve adherence for patients.

• The TRADITiONAL Study is a global, randomised, multi-centre, open-label, parallel-group Phase III clinical trial. It is designed to compare the efficacy and safety of Orphalan's investigational once-daily trientine tetrahydrochloride formulation against D-penicillamine, a currently used copper-chelating agent, as a first-line therapy for Wilson disease. The trial involves a 48-week treatment period following randomisation.
• The study is actively recruiting both symptomatic and asymptomatic patients aged eight years and above. Eligible participants include those who are new to all Wilson disease therapies or have not previously received any chelator treatment. Additionally, patients who have used zinc salts for a limited period of up to 28 days may also qualify for enrolment, broadening the potential participant pool.
• Orphalan's initiative aims to tackle the significant challenges associated with current Wilson disease management. Existing lifelong therapies are often complex and burdensome, leading to adherence issues. The development of a once-daily trientine formulation seeks to simplify the treatment regimen, potentially improving patient compliance and overall quality of life by reducing the daily treatment burden.

Unpacking the TRADITiONAL Study Design for Wilson Disease

Clinical trials in Wilson disease have historically varied in design, population, and endpoints, reflecting the rarity and phenotypic heterogeneity of the condition. The studies below span retrospective cohort analyses, systematic reviews, and a single randomized trial, collectively informing current understanding of chelator and zinc-based therapies.

Addressing Unmet Needs in Lifelong Wilson Disease Management

Despite the availability of multiple pharmacological options, Wilson disease (WD) management carries persistent challenges that span treatment tolerability, patient adherence, and monitoring reliability. These limitations have direct implications for long-term disease control and patient outcomes.

• Neurological worsening under therapy: Neurological worsening (NW) occurs in two distinct patterns — an early peak (within 3 months of treatment initiation) observed in 26.1% of patients with neurological or mixed presentation, and a late peak (after >12 months) seen in 20% of those with neurological or mixed presentation and in 4.4% of patients with a hepatic or asymptomatic presentation. Early NW was attributed to treatment initiation and pre-existing neurological damage; late NW is likely associated with non-adherence. NW was observed with D-penicillamine, trientine, and zinc therapy. Reversibility was partial: 50% of early NW cases and 81% of late NW cases resolved.

• Penicillamine-associated neurological risk: Penicillamine (PA) makes 10–50% of patients with neurologic symptoms neurologically worse at the early stage of administration. Studies in the toxic milk mouse model of WD indicated that PA elevated free copper concentrations in the serum and brain, with correspondingly increased oxidative stress markers (decreased GSH/GSSG and increased MDA concentrations in the cortex and basal ganglia), suggesting that elevated free copper in the brain may underlie this worsening.

• Adherence difficulties and cold storage requirements: Poor compliance is identified as a major problem in WD management, particularly in adolescents and patients with psychiatric disorders. Trientine dihydrochloride (TETA 2HCL) requires storage at 2–8 °C, and interruption of this treatment was frequent, with the primary reasons for stopping linked to cold storage issues and adherence difficulties. In a retrospective cohort, the mean treatment sequence duration was significantly shorter for TETA 2HCL (7.6 years) compared to TETA 4HCL (12.6 years) (p = 0.011).

• Adverse event profiles of first-line chelators: Analysis of the FDA Adverse Event Reporting System (FAERS) identified 1,452 AEs related to penicillamine and 760 related to trientine. The most commonly reported AEs were drug hypersensitivity for penicillamine and tremor for trientine. Potential safety signals requiring further validation included decreased bone density and brain atrophy for penicillamine, and memory impairment, oesophageal ulcer, and starvation for trientine.

• Limitations of copper monitoring biomarkers: The use of biomarkers to monitor chelation therapy — including non-ceruloplasmin-bound copper (NCC) measured by protein speciation (NCC-Sp) and exchangeable copper (NCC-Ex), as well as 24-hour urinary copper excretion (UCE) — is poorly supported by data. The visit-to-visit coefficient of variance was 30% for NCC-Sp, 20% for NCC-Ex, and 52% for UCE. Biomarker values did not reach steady state until week 60, and the response to a dose change may take as long as 6–12 months to achieve. The high variation in UCE and its lack of association with clinical outcome question its current use to guide dosing in patients with stable disease.

• Genetic factors predicting treatment response: Younger age of onset, the presence of dystonia, and a severe mutation genotype (carrying at least one frameshift, splicing, or nonsense mutation) were found to be predictive of neurological worsening in neurological WD patients receiving chelator therapy, with neurological worsening completely irreversible in 6 cases (20.7%) and partially irreversible in 16 cases (55.2%) among those who deteriorated.

• Dosing complexity and simplification challenges: Multiple daily dosing requirements contribute to adherence burden. A preliminary real-life feasibility study of single daily dose (SDD) maintenance therapy across 26 patients (D-penicillamine=13, trientine=8, zinc=5) reported treatment failure in 5 patients over a median follow-up of 41 months, with SDD effective in 21/26 patients (81%). The authors noted that SDD could be considered in some WD patients, though the study was characterized as a pilot study.

Current Standard of Care for Wilson Disease: D-Penicillamine and Beyond

The pharmacological management of Wilson disease (WD) centers on two principal therapeutic strategies: chelating agents and zinc salts. The EASL-ERN Clinical Practice Guidelines recommend pharmacological therapy comprising chelating agents — penicillamine and trientine — and zinc salts, with the important qualification that only chelators are recommended for significant liver disease. The treatment paradigm described in the literature follows an initial active and prolonged chelating phase with D-penicillamine or trientine, followed by maintenance with trientine or zinc salt. Over recent years, less toxic alternatives have gradually displaced D-penicillamine as the preferred first-line agent: trientine or tetrathiomolybdate has been increasingly recommended as the first-line treatment for neurological WD, given the frequent side effects and initial neurological deterioration associated with penicillamine therapy. For asymptomatic or presymptomatic patients, initial zinc therapy has been shown to be safe and effective, as has maintenance zinc therapy in patients following long-term chelation.

Neurological worsening (NW) represents a recognized and clinically significant complication of treatment initiation. Early NW, occurring within the first 3 months of therapy, was observed in 30 out of 115 (26.1%) patients with neurological or mixed presentation, and was not observed in patients with a purely hepatic or asymptomatic presentation (0%). Late NW, occurring after more than 12 months, was seen in a further 23 (20%) patients with neurological or mixed presentation and in 13 out of 294 (4.4%) patients with a hepatic or asymptomatic presentation. NW was observed with D-penicillamine, trientine, and zinc therapy, and was reversible in 15/30 (50%) with early NW and in 29/36 (81%) with late NW. In pediatric and adolescent patients who experienced NW on D-penicillamine, management with trientine or zinc monotherapy with a copper-restricted diet has been described, with gradual clinical and functional improvement observed in 24 out of 27 such cases.

Monitoring of therapy is integral to long-term management. The EASL-ERN guidelines specify that monitoring is based on clinical symptoms, liver tests, and copper metabolism — including urinary copper excretion and exchangeable copper — to detect poor compliance and over- or under-treatment. The 24-hour urinary copper excretion (UCE) is a recommended tool for both diagnosis and treatment follow-up; in children, UCE decreases to ≤8 μmol/day after 1 year of treatment and to <6 μmol/day after 5 years. Butyrylcholinesterase (CHE) serum levels have been identified as a sensitive biomarker for detecting compliance problems in long-term treated WD patients, demonstrating greater sensitivity than serum copper, non-ceruloplasmin-bound free copper, or ceruloplasmin levels for this purpose. Over-treatment carries its own risks: copper deficiency peripheral neuropathy caused by excessive chelation has been reported, underscoring the importance of monitoring copper metabolism during the stable phase of treatment. Liver transplantation is the recommended therapeutic option in WD with acute liver failure or end-stage liver cirrhosis, and its indication should be considered when neurological status deteriorates rapidly despite effective chelation; however, liver transplantation is not recommended as primary treatment for neurological WD.

Trientine Tetrahydrochloride's Place in the Wilson Disease Landscape

Standard-of-care treatments for Wilson disease (WD) — D-penicillamine, trientine, and zinc — have established clinical utility but carry meaningful limitations. A systematic review of 13 studies (one randomized trial and 12 observational studies) found that D-penicillamine is probably most effective for patients with hepatic presentation, while zinc is preferred over D-penicillamine for presymptomatic and neurological patients, given a more favorable tolerance profile with no obvious differences in clinical efficacy between the two in those subgroups. However, the review characterized the available evidence as generally of low validity and heterogeneous, underscoring the absence of high-quality comparative data. Neurological worsening (NW) remains a persistent challenge across all three standard agents: early NW (within the first 3 months of therapy) was observed in 30 out of 115 (26.1%) patients with neurological or mixed presentation, and late NW (after more than 12 months) occurred in a further 23 (20%) of the same group and in 13 out of 294 (4.4%) of patients with hepatic or asymptomatic presentation.

Tetrathiomolybdate (TTM) and its derivative bis-choline tetrathiomolybdate (WTX101) represent the most clinically advanced investigational alternatives. In a phase III clinical trial, TTM stabilized neurological function in patients with WD, causing significant recovery in 81% of patients at 3 years post initiation of therapy. WTX101, a once-daily oral copper-protein-binding agent, demonstrated in a proof-of-concept phase II trial that it rapidly lowered non-ceruloplasmin-bound copper (NCC) levels over 24 weeks, accompanied by improved neurological status "without apparent initial drug-induced paradoxical worsening," reduced disability, and stable liver function with a favorable safety profile. This absence of paradoxical worsening is a clinically meaningful distinction from standard chelators, with which early NW was reversible in only 15/30 (50%) of affected patients. The most common clinical side effects observed for TTM across indications have been anemia, neutropenia, leukopenia, and transaminase elevations, generally resolved with dose adjustment or temporary suspension.

For patients with neurological WD unresponsive to medical therapy, liver transplantation (LT) has been evaluated as a rescue strategy. Among survivors beyond 1 year, 86.3% of patients who underwent LT for neurological deterioration showed improvement or complete recovery from neurological WD, compared with 79.7% in those transplanted for end-stage liver disease. Gene therapy with VTX-801, an adeno-associated vector-based agent designed to restore the mutated ATP7B copper transporter, is at an earlier stage; mechanistic modeling has identified the 48/2-hour plasma radioactivity ratio as a potential decision criterion to differentiate responders from non-responders, and simulations suggest that relative exchangeable copper (REC) may serve as a suitable non-radioactive biomarker for assessing ATP7B gene therapy response.

Orphalan's Trientine Trial: A New Era for Wilson Disease Adherence

Wilson disease is a lifelong battle, and current treatments, while effective, come with significant hurdles. D-penicillamine, a long-standing option, is often associated with adverse events leading to discontinuation, impacting up to 30% of patients. Trientine, an alternative, has shown comparable overall efficacy but some studies indicate a higher incidence of neurological deterioration when used as initial therapy. Beyond side effects, the complexity of regimens—often requiring multiple daily doses before meals—contributes to a substantial non-adherence rate, with some studies reporting over 75% of patients not fully compliant. This directly affects long-term outcomes and patients' health-related quality of life, particularly their emotional well-being.

Orphalan's TRADITiONAL study, evaluating a once-daily trientine tetrahydrochloride formulation as first-line therapy, directly addresses these critical unmet needs. By simplifying the dosing schedule, the company aims to significantly improve patient adherence and satisfaction, which existing evidence strongly links to better progression-free survival. This strategic move could solidify trientine's position as a preferred initial treatment, especially given its established non-inferiority to penicillamine in maintenance settings and a generally more favorable adverse event profile.

However, the path forward is not without considerations. The trial must rigorously demonstrate that the once-daily formulation maintains the efficacy and safety profile of existing trientine, particularly regarding the nuanced risk of neurological deterioration observed in some trientine-treated cohorts. Furthermore, while a simplified regimen can boost adherence, factors like drug cost, especially in the diverse global markets targeted by the trial, will remain crucial determinants of real-world uptake and patient access. Success here could redefine the standard of care, offering a more patient-centric approach to managing this challenging rare disease.