Dimerix Successfully Completes Recruitment for Phase 3 ACTION3 Trial of DMX-200

Dimerix Completes Recruitment for the ACTION3 Trial

Dimerix Limited, a biopharmaceutical company focused on kidney disease, has announced the completion of recruitment in its pivotal Phase 3 clinical trial for DMX-200, targeting patients with focal segmental glomerulosclerosis (FSGS). The trial has successfully enrolled and dosed its landmark 286th adult patient, a crucial step in understanding the drug's efficacy and safety profile.

Overview of the ACTION3 Trial

The ACTION3 trial is designed as a multi-center, randomized, double-blind, placebo-controlled study. Its primary objective is to assess the efficacy and safety of DMX-200 when used in conjunction with a standard blood pressure therapy known as an angiotensin II receptor blocker (ARB). The study duration spans two years, during which patients will receive either DMX-200—administered as a 120 mg capsule twice a day—or a placebo. The study aims to generate substantial clinical evidence that could bolster the case for marketing approval, particularly through measurable outcomes related to proteinuria reduction and kidney function.

As part of the recruitment process, patients underwent a stabilization phase on an ARB before being randomized into treatment groups. Currently, 69 out of 286 adult patients have completed the full 2-year treatment, and an impressive 94% of those have opted to participate in the Open Label Extension (OLE) study, indicating strong preliminary interest in continuing their treatment.

Research and Regulatory Pathway

Dimerix's ACTION3 trial has successfully cleared multiple Independent Data Monitoring Committee (IDMC) reviews without necessitating protocol modifications or raising any safety concerns. Following analysis and favorable results from a recent collaboration with Amicus Therapeutics, Dimerix aims to engage with the FDA regarding clinical trial endpoints before moving forward with data analysis.

Significantly, the trial also includes an independent cohort of pediatric patients, with ongoing recruitment that may expand the drug's application for younger demographics pending successful outcomes.

Future Prospects

Dimerix's sound funding position ensures that the trial, along with potential new R&D opportunities, can continue without interruption. This financial stability complements the promising preliminary results seen thus far. In March 2024, an interim analysis of the first 72 randomized patients indicated that DMX-200 might significantly outperform placebo in reducing proteinuria, a well-established marker for kidney disease progression.

Dr. Nina Webster, CEO of Dimerix, expressed pride in reaching this recruitment milestone, highlighting the dedication and operational competence of the team in such complex and rare disease contexts. The trial has involved 219 sites across 21 countries, fostering a robust international collaboration.

Conclusion

The completion of patient recruitment for the ACTION3 trial is a critical leap toward potential commercialization of DMX-200. As patient data continues to be gathered over the next two years, Dimerix is anticipating key milestones that could pivotally influence the future of treatments for patients suffering from FSGS. With regulatory approvals on the horizon, the company is optimistic about the impact DMX-200 could have in the realm of kidney disease management.

For additional information about the ACTION3 study, refer to ClinicalTrials.gov or the Australian New Zealand Clinical Trials Registry.

This article is based on the announcement made by Dimerix on December 15, 2025, and covers initial findings and anticipated pathways for DMX-200.