Dimerix phase III kidney disease trial strengthened by PARASOL data

• Final data analysis by the PARASOL collaboration with Dimerix generally consistent with broader analysis of FSGS patient data in 2024
• Potential relationship was observed between proteinuria at 12 months and subsequent risk of kidney failure.
• The relationship will now be discussed with US FDA to explore possible approval pathways for DMX-200

Special Report: Final data analysis from the Dimerix collaboration with PARASOL reinforces the company’s proteinuria-based endpoints in its phase III ACTION3 trial of lead drug DMX-200 in rare kidney disease Focal Segmental Glomerulosclerosis (FSGS).  

The PARASOL group’s analysis of observational data from major renal registries was conducted to provide Dimerix (ASX:DXB) with additional rationale supporting the choice of proteinuria endpoints at 104 weeks for the ACTION3 study for potential US marketing approval.

Additionally, the analysis explored the relationship between proteinuria endpoints at 12 months and the subsequent risk of kidney failure, alongside estimated Glomerular Filtration Rate eGFR endpoints, to support a potential application for accelerated approval.

eGFR is a key measure of kidney function and the rate at which kidneys filter blood, removing waste and excess fluid.

The PARASOL analysis employed a patient population that emulated the ACTION3 clinical study population, using the major ACTION3 inclusion and exclusion criteria.

Dimerix said pleasingly, results of the latest analysis were generally consistent with the broader PARASOL analysis conducted in 2024, which supported the use of proteinuria as an endpoint for FSGS clinical trials.

The company said results could not be disclosed at this time, as they were based on the analysis of PARASOL observational data (not ACTION3 data) and remained subject to commercial-in-confidence restrictions.

104-week data support proteinuria endpoints

The latest PARASOL analysis reinforces proteinuria as a meaningful measure of kidney health in adults with FSGS over 104 weeks of two years.

The analysis supports two primary endpoint approaches for the proposed US approval pathway including:

• Percentage change in proteinuria from baseline; and
• Responder-based analysis, which tracks the proportion of patients achieving a meaningful reduction in proteinuria

In April 2025 Dimerix reported that the US Food and Drug Administration (FDA) confirmed these measures as acceptable primary endpoints, either as the percentage of patients achieving a defined reduction compared to placebo or the overall percentage change from baseline after two years.

52-Week PARASOL analysis

A potential relationship between proteinuria at 52 weeks or one year and subsequent risk of kidney failure was also observed.

Dimerix said it would discuss with the FDA this potential link between proteinuria-based endpoints at 12 months, to support marketing approval, and subsequent use of eGFR-based endpoints over 24 months as confirmatory data.

If the FDA agrees and the blinded ACTION3 analysis confirms the statistical assumptions for eGFR endpoints, Dimerix will consider formal evaluation of these earlier measures for potential submission.

Dimerix and its US partner Nasdaq-listed Amicus Therapeutics intend to seek feedback from the FDA on the new PARASOL findings in the coming months before completing the planned blinded analysis of the ACTION3 data, to align on 104-week endpoints, as well as any potential accelerated approval submission.

Dimerix said it continued to work with its commercial partners across key territories to determine the potential for alternative approval pathways outside of the US.

Source: Dimerix

About the FSGS and ACTION3

FSGS is a kidney disease characterised by scarring in the glomeruli, the tiny filters in the kidneys.

The scarring disrupts the kidney’s ability to filter waste from the blood, reducing their overall function and increasing the presence of proteins in urine.

The disease, which affects adults and children, is rare with about seven people per million in the US.

There are few effective treatments and managing the disease typically involves blood pressure control, efforts to reduce protein in urine and immunosuppressive drugs to help modulate the immune system.

Dimerix’s Angiotensin II Type 1 Receptor (AT1R) & Chemokine Receptor 2 (CCR2) Targets for Inflammatory Nephrosis (ACTION3) trial is a phase III, multi-centre, randomised, double-blind, placebo-controlled study.

It is evaluating the efficacy and safety of DMX200 in patients with FSGS who are receiving a stable dose of an angiotensin II receptor blocker (ARB).

‘In line with our expectations’

Dimerix chief medical officer Dr David Fuller has welcomed the findings, which he said were in line with expectations.

“Pleasingly, the PARASOL collaboration analysis outcome is in line with our expectations and, consistent with the initial PARASOL analysis, demonstrates a relationship between proteinuria at both the 12-month and 24-month time points and subsequent risk of kidney failure, when assessed using both responder analysis and percent change from baseline,” he said.

“We look forward to discussing these findings with the FDA in due course.

“These outcomes are a testament to the collaborative nature of the PARASOL group, and their statistical lead – Dr Abigail Smith (Associate Professor of Biostatistics and Informatics at Northwestern University).”

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