Monopar Therapeutics Inc. (Nasdaq: MNPR) has initiated a rolling New Drug Application (NDA) submission to the U.S. Food and Drug Administration (FDA) for ALXN1840 (tiomolibdate choline, TMC), a treatment for Wilson disease, the company said in a press release.

The FDA has authorized Monopar to submit the NDA on a rolling basis, allowing completed sections to be reviewed while the company finalizes remaining sections. Monopar said it has already submitted the first completed sections.

ALXN1840 is described by the company as a first-in-class albumin tripartite complex (ATC) activator. If the NDA is accepted and approved, Monopar claims it would be the first therapy with a novel mechanism of action approved in the United States for Wilson disease in decades.

In a Phase 3 pivotal trial, ALXN1840 met its primary endpoint, demonstrating copper mobilization significantly greater than standard of care over 48 weeks in both previously treated and treatment-naïve patients. Clinical data were gathered across 645 patient-years of follow-up in 266 patients.

ALXN1840 holds Fast Track, Orphan Drug, and Rare Pediatric Disease (RPD) designations from the FDA. The RPD designation, granted in June 2026, makes the company potentially eligible to receive a Pediatric Priority Review Voucher upon NDA approval.

Wilson disease is a rare genetic disorder affecting approximately 1 in 30,000 people worldwide, caused by mutations in the ATP7B gene that impair the body's ability to excrete copper, leading to toxic copper accumulation in the liver, brain, and other organs.