FDA Requests More Data, Delays Key Analysis in Dimerix’s Kidney Disease Study

FDA Feedback Validates Trial Endpoint

Dimerix Limited, an Australian biopharmaceutical company, has received a significant regulatory nod from the U.S. Food and Drug Administration (FDA) regarding its Phase 3 clinical trial for DMX-200, a drug candidate targeting focal segmental glomerulosclerosis (FSGS), a rare and serious kidney disease. The FDA has confirmed that the percent reduction of proteinuria; excess protein in urine; after two years is an appropriate primary endpoint to support full approval of DMX-200, should the trial results be positive.

This endorsement is a critical milestone for Dimerix, as proteinuria reduction is widely regarded as a meaningful surrogate marker for kidney disease progression. The FDA also agreed that changes in estimated glomerular filtration rate (eGFR), a measure of kidney function, can serve as a secondary endpoint in the ACTION3 trial.

Next Steps and Timing

While the FDA’s feedback is encouraging, the agency has requested additional information and documentation from Dimerix to ensure the integrity of the trial before allowing the planned blinded statistical powering analysis to proceed. This analysis, which helps determine the trial’s statistical strength without unblinding treatment assignments, is now expected to take place in early 2026.

Dimerix has committed to providing the requested materials shortly, signaling its intent to maintain regulatory compliance and transparency. The timing of this analysis is pivotal, as it will influence subsequent protocol updates and the overall trajectory toward potential marketing approval.

About the ACTION3 Trial and DMX-200

The ACTION3 Phase 3 trial is a randomized, double-blind, placebo-controlled study evaluating DMX-200’s efficacy and safety in patients with FSGS who are already on stable doses of angiotensin II receptor blockers (ARBs), the current standard of care for hypertension and kidney disease. Patients receive either DMX-200 or placebo over a two-year period, with the trial designed to capture robust data on proteinuria reduction and kidney function decline.

DMX-200 is a chemokine receptor antagonist with orphan drug designation in the U.S., offering potential market exclusivity and patent protection through 2032, with possible extensions to 2042. The drug’s mechanism targets inflammatory pathways implicated in FSGS, a disease with limited treatment options and a high unmet medical need.

Implications for Patients and Investors

FSGS affects over 40,000 people in the U.S. alone and often leads to end-stage kidney disease within five years of diagnosis. Current treatments are largely non-specific and immunosuppressive, underscoring the urgent need for targeted therapies like DMX-200. The FDA’s confirmation of the trial’s primary endpoint enhances confidence in the regulatory pathway and could accelerate access to a novel treatment if the trial meets its goals.

For investors, this development reduces a key regulatory risk and provides a clearer timeline for upcoming trial milestones. However, the delay in the blinded statistical analysis introduces some uncertainty around the timing of data readouts and potential approval.