Monopar Announces Publication of Phase 2 Study Demonstrating ALXN1840 Significantly Improves Copper Balance in Patients with Wilson Disease (Form 8-K)

Monopar Announces Publication of Phase 2 Study Demonstrating ALXN1840 Significantly Improves Copper Balance in Patients with Wilson Disease

WILMETTE, Ill., May 19, 2026 (GLOBE NEWSWIRE) -- Monopar Therapeutics Inc. ("Monopar" or the "Company") (Nasdaq: MNPR), a clinical-stage biopharmaceutical company developing innovative treatments for patients with unmet medical needs, today announced that Hepatology Communications has published a peer-reviewed manuscript entitled "Effect of Tiomolibdate Choline on Copper Balance in Patients with Wilson Disease: an Open-label Phase 2 Trial."

The publication, which can be found online at https://journals.lww.com/hepcomm/fulltext/2026/06010/effect_of_tiomolibdate_choline_on_copper_balance.7.aspx, reports results from the Phase 2 ALXN1840-WD-204 study (NCT04573309) and demonstrates that ALXN1840 (tiomolibdate choline) produces a rapid, statistically significant, and sustained improvement in daily copper balance in patients with Wilson disease, driven by increased fecal copper excretion.

Wilson disease is a rare and progressive genetic condition in which the body's pathway for removing excess copper is compromised, leading to damage from toxic copper build-up in organs such as the liver and brain.

The open-label, single-arm Phase 2 trial evaluated daily dosing of ALXN1840 in nine patients with Wilson disease across two centers in the United Kingdom and New Zealand. Patients were admitted to a clinical research unit and initiated on a copper-controlled diet, with all copper intake and output collected during a pre-treatment baseline period and after initiation of daily ALXN1840 over multiple weeks.

The publication builds on a recently published peer-reviewed Journal of Hepatology Letter to the Editor (https://www.journal-of-hepatology.eu/article/S0168-8278(25)02483-3/fulltext), which highlighted the importance of comparing outcomes to a pre-treatment baseline to accurately assess the effect of a potential Wilson disease treatment on copper balance.

Key findings reported in the publication:

Notably, the observed improvements in copper balance and copper mobilization occurred in a Wilson disease patient population with a mean prior current standard of care treatment duration of 16 years, suggesting that despite years of treatment with currently available therapies, patients present with a considerable amount of residual copper in the body that ALXN1840 is able to mobilize and eliminate. This finding is consistent with data from the completed 48-week Phase 3 trial, in which ALXN1840 demonstrated superior copper mobilization compared to standard of care even in patients with a mean prior standard of care treatment duration of 11 years.

"These findings highlight ALXN1840's ability to rapidly improve copper balance in Wilson disease, reinforcing its promise as a meaningful new treatment option," said Professor Aftab Ala, MBBS, MD, FRCP, PhD, Consultant Hepatologist at The Roger Williams Institute of Liver Studies, King's College London, and King's College Hospital, London, and lead author of the publication.

About Monopar Therapeutics Inc.

Monopar Therapeutics is a clinical-stage biopharmaceutical company with late-stage ALXN1840 for Wilson disease, and radiopharmaceutical programs including MNPR-101-Zr (Phase 1) for imaging advanced cancers along with MNPR-101-Lu (Phase 1a) and MNPR-101-Ac (late preclinical) for the treatment of advanced cancers. For more information, visit: www.monopartx.com.

About ALXN1840

ALXN1840 (tiomolibdate choline, TMC) is a novel first-in-class Albumin Tripartite Complex (ATC) activator under investigation for the treatment of Wilson disease. ALXN1840 rapidly mobilizes and tightly sequesters excess copper in ATCs, suppressing its redox reactivity, limiting oxidative damage, and blocking transport across the blood-brain barrier. In the Phase 3 pivotal trial, ALXN1840 demonstrated rapid and sustained copper mobilization (primary endpoint) that was significantly greater than standard of care over 48 weeks in both previously treated and untreated patients. Durable clinical improvement and a favorable safety and tolerability profile were observed across 645 patient-years of follow-up in 266 patients.