Monopar Presents Phase 2 ALXN1840 Data Demonstrating Liver Disease Stabilization and Neurologic Improvement in Treatment-Experienced Wilson Disease Patients at EASL 2026

Monopar's ALXN1840 Shows Liver Stabilization, Neurologic Improvement in Wilson Disease

Monopar Therapeutics announced Phase 2 ALXN1840-WD-205 data presented at EASL 2026, showing ALXN1840 (tiomolibdate choline) stabilized liver disease and improved neurological symptoms and quality of life in 29 heavily pre-treated Wilson disease patients over 48 weeks. The open-label, multicenter trial demonstrated a high rate of liver pathology stabilization or improvement across various histologic measures. Significant improvements were observed in neurologic symptoms, global clinical status, and patient-reported quality of life, all with statistical significance (p < 0.05). ALXN1840 was generally well tolerated, with most adverse events being nonserious and mild. These positive results, in a challenging patient population, underscore ALXN1840's potential to address critical unmet medical needs in Wilson disease, building upon prior Phase 3 findings.

• Significant Liver Pathology Stabilization and Improvement: The Phase 2 trial demonstrated robust liver pathology benefits, with a high preponderance of patients showing stabilization or improvement across multiple histologic measures by Week 48. Specifically, 96% of patients experienced stabilization or improvement in hepatocyte necrosis, 88% in steatosis grade, 79% in lobular inflammation, and 67% in fibrosis stage, indicating a broad positive impact on hepatic health in this heavily pre-treated population.
• Clinically Meaningful Neurologic and Quality of Life Enhancements: ALXN1840 treatment led to significant improvements in neurological symptoms, as evidenced by a statistically significant reduction in the Unified Wilson Disease Rating Scale (UWDRS) Part III score (p < 0.05) at Week 48. Additionally, patients reported significant enhancements in their overall quality of life, measured by the EuroQoL 5-Dimensions (EQ-5D) UK Health Index (p < 0.05), alongside improvements in global clinical status (CGI, p < 0.05).
• Favorable Safety Profile in Treatment-Experienced Patients: ALXN1840 exhibited a generally well-tolerated safety profile throughout the 48-week study and its extension period. The majority of treatment-emergent adverse events were nonserious and mild to moderate in severity (Grade 1 or 2). This consistent safety profile in a population with extensive prior treatment underscores the drug's potential as a viable therapeutic option for Wilson disease patients who often face significant safety risks with current standard of care therapies.

Why New Options are Needed for Wilson Disease Patients

Current Wilson disease treatments face significant efficacy and safety challenges that underscore the need for improved therapeutic options. Evidence shows substantial gaps in treatment response rates and concerning adverse effects with existing therapies. These limitations create barriers to optimal patient outcomes and highlight opportunities for therapeutic advancement.

• Suboptimal treatment response rates: Only 64% of patients treated with penicillamine achieve normalized serum ALT levels, and switching to zinc therapy shows even lower success rates with only 23% of patients normalizing ALT levels

• Persistent liver dysfunction despite appropriate treatment: 36% of pediatric patients with Wilson disease-related liver disease maintain elevated liver enzymes despite receiving standard penicillamine or zinc therapy

• Penicillamine-associated neurological worsening: Penicillamine therapy carries significant risk of exacerbating neurological symptoms, particularly in patients presenting with neurological manifestations, potentially causing permanent neurological damage

• Zinc monotherapy limitations for acute presentations: Zinc's slow onset of action makes it suboptimal for initial treatment of patients with neurological disease, with only 50% of patients achieving normalized ALT levels

• Diagnostic delays leading to irreversible damage: Up to two-thirds of cases may be initially misdiagnosed with diagnostic delays averaging 2 years, increasing the risk of permanent liver and brain damage

• Lack of standardized treatment approaches: Significant variability exists in initial therapy selection among providers, with no identified predictive factors for treatment response

• Higher mortality risk with hepatic presentations: Patients presenting with liver disease face five-fold higher mortality risk compared to those with neurological presentations, indicating inadequate management of severe hepatic manifestations

• Insufficient evidence for combination therapies: Despite widespread use of combination chelator and zinc therapy, this approach requires further clinical exploration to establish optimal protocols

ALXN1840 Phase 2 Data Shows Liver Stabilization, Neurologic Improvement

Recent clinical evidence for Wilson disease has emerged primarily from the Chelate study, a randomized controlled trial examining optimal chelation monitoring strategies. This post-hoc analysis provided important insights into biomarker response patterns and the comparative effectiveness of established chelation therapies in clinically stable patients.

• Chelate Study (NCT03539952): Randomized 53 clinically stable Wilson disease patients to continued penicillamine (DPA) versus same-dose trientine-tetrahydrochloride (TETA4) for 48 weeks, demonstrating significant reductions in non-ceruloplasmin copper levels with NCC-Sp decreasing from 57.9±21.1μg/L to 39.6±16.25μg/L (P=0.0002) and NCC-Ex from 56.4±20.3μg/L to 46.2±11.5μg/L (P=0.01)

• Biomarker optimization findings: Patients maintaining steady-state NCC-Ex and NCC-Sp below 50 μg/L (lower than the commonly recommended 50-150 μg/L range) demonstrated stable hepatic function markers including ALT, AST, S-albumin, and S-protein, while values above 50 μg/L correlated with hepatic function deterioration

• Extended monitoring requirements: Biomarker values required up to 60 weeks to reach steady state, with dose change responses taking 6-12 months to achieve, indicating substantially longer monitoring periods than previously recognized for treatment optimization

• Urinary copper excretion variability: UCE demonstrated high visit-to-visit coefficient of variance (52%) compared to NCC-Sp (30%) and NCC-Ex (20%), with UCE dropping approximately 50% after TETA4 switch, questioning the reliability of UCE for therapeutic monitoring in stable disease

• Safety profile: No neurological deterioration occurred despite copper biomarker variations between treatment arms, and copper deficiency was not observed with either chelation regimen during the 48-week treatment period

ALXN1840's Promise: A New Horizon for Wilson Disease?

The recent presentation of Phase 2 ALXN1840-WD-205 data for ALXN1840 in Wilson disease patients represents a significant step forward in addressing a challenging rare genetic disorder. For patients grappling with the debilitating effects of copper accumulation in the liver and brain, the prospect of a therapy that not only stabilizes liver pathology but also significantly improves neurological symptoms and quality of life is profoundly impactful. This is particularly true for the heavily pre-treated population studied, where existing therapies often fall short due to efficacy limitations, safety concerns, or complex dosing regimens.

ALXN1840's mechanism, involving the formation of a tripartite complex with copper and albumin, offers a differentiated approach. Research indicates it effectively reduces non-ceruloplasmin-bound copper (NCC) and, importantly, may prevent copper-induced blood-brain barrier damage, a critical factor given the risk of neurological worsening with some conventional treatments. The reported once-daily dosing and generally well-tolerated profile could enhance patient adherence, a perennial challenge in chronic conditions requiring lifelong therapy.

However, as with any emerging therapy, careful consideration of the full data landscape is essential. While the latest Phase 2 results are encouraging regarding safety, earlier studies of ALXN1840 (then WTX101) did report serious adverse events, including psychiatric disorders and elevated liver enzymes, which will require continued monitoring in larger trials. Furthermore, preclinical data highlighted potential mitochondrial damage at high doses, underscoring the importance of precise dose optimization. The evolving understanding of its mechanism, particularly the finding that it primarily reduces intestinal copper uptake rather than increasing biliary excretion in humans, suggests a nuanced therapeutic profile that will inform its optimal clinical application. These insights will be crucial as ALXN1840 progresses, potentially offering a new, impactful option for Wilson disease management.