Dimerix (ASX: DXB) has announced the final adult patient has been dosed in its ACTION3 trial for DMX-200 in FSGS, enhancing statistical power and de-risking the path towards regulatory submission and licensing.
Dimerix has dosed 333 adult patients in the pivotal Phase 3 trial, surpassing the target of 286, with adult recruitment now closed.
Paediatric recruitment continues as a separate cohort, aligning with regulators' agreement.
The trial involves 219 sites across 21 countries, with patients receiving either DMX-200 or placebo, added to stable ARB therapy at a dosage of 120 mg capsule BID.
Trial Progress and Oversight
The Independent Data Monitoring Committee (IDMC) has conducted seven reviews for the ACTION3 trial.
Critically, these reviews have found no protocol changes or safety concerns.
The full 2-year study treatment period for adult patients is expected to conclude in March 2028.
The next key step involves a blinded powering analysis of the primary endpoint, a process aligned with US Food and Drug Administration (FDA) guidance.
Regulatory and Licensing Outlook
The over-recruitment significantly strengthens the statistical power for the primary endpoint analysis—a positive development for potential regulatory submission.
The company noted ongoing licensing opportunities for DMX-200, suggesting that successful trial progression and strong data could further bolster these discussions in unlicensed territories.
Previous FDA feedback had reconfirmed percent reduction in proteinuria as a suitable primary endpoint for traditional approval via the 505(b)(1) pathway, with eGFR as a secondary endpoint.
Past Developments
In late 2025, BioMarin announced its intention to acquire Dimerix's US partner, Amicus Therapeutics, for US$4.8 billion.
Dimerix retains eligibility to receive up to US$590 million in upfront, development, and sales milestones plus royalties from its US licensing deal, independent of Amicus's ownership.
Prior to this, in December 2025, Dimerix completed the target recruitment for the ACTION3 trial, noting high patient retention in the open-label extension.
The company also indicated a strong cash position at that time, though more recent filings highlight a funding runway of approximately 3.5 quarters.
Dimerix has previously secured licensing deals for DMX-200 in Europe, Canada, Australia, and other territories, including with Advanz Pharma Corp, Taiba, and Fuso.
These deals collectively represent potential upfront and milestone payments of up to AU$1.4 billion, with over AU$65 million received to date.
