First patient completes four years in DMX-200 clinical program
Dimerix Limited (ASX: DXB) has reached a meaningful clinical development milestone, with the first patient completing both the two-year ACTION3 Phase 3 trial and the subsequent two-year Open Label Extension (OLE) study, representing four continuous years of participation in the DMX-200 program. The milestone was announced on 5 October 2026 and relates to the company’s lead treatment candidate for focal segmental glomerulosclerosis (FSGS), a rare and serious kidney disease with significant unmet medical need.
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What is FSGS and why does it matter to investors?
Focal segmental glomerulosclerosis is a rare, progressive kidney disease characterised by scarring of the glomeruli, the kidney’s filtering units. This scarring leads to proteinuria (protein leaking into urine), declining kidney function, and frequently end-stage renal disease requiring dialysis or transplantation.
The disease represents a substantial unmet medical need, with no therapies specifically approved for FSGS in the United States. Key facts investors should understand:
- More than 40,000 people in the US are estimated to be living with FSGS, including adults and children
- In patients with progressive or treatment-resistant FSGS, the average time from diagnosis to end-stage kidney disease can be as short as five years
- Disease recurrence after kidney transplantation occurs in up to 60% of cases
- DMX-200 targets the CCR2 receptor (an inflammatory pathway) in combination with standard-of-care angiotensin II receptor blocker (ARB) therapy
The absence of approved treatment options means a successful Phase 3 outcome for DMX-200 could represent a high-value regulatory event in a rare disease market with no specifically approved therapies.
93% patient retention signals strong real-world confidence in DMX-200
Of the 96 patients who have completed the ACTION3 Phase 3 trial to date, 89 have elected to join the OLE study, representing a continuation rate of 93%. The OLE study is entirely optional for patients following their completion of the blinded Phase 3 trial, making this level of uptake a meaningful signal of confidence from patients, investigators, and study sites.
All participants in the OLE receive DMX-200 for up to two years, regardless of whether they received the drug or placebo during the blinded phase. Data collected from the OLE study may support future regulatory and commercial activities for DMX-200.
Dr Nina Webster, CEO and Managing Director, Dimerix
“The completion of four years of study participation by the first patient in our DMX-200 clinical program represents an important milestone for both Dimerix and the broader FSGS community. Long-term participation of this nature reflects the commitment of patients, their families and clinical investigators, and provides an opportunity to gather valuable longer-term information on DMX-200. We are particularly encouraged that over 90% of eligible patients completing the ACTION3 study have elected to continue into the Open Label Extension study…”
| Program Phase | Duration | Status | Patients |
|---|---|---|---|
| ACTION3 Phase 3 (blinded) | 2 years | Ongoing (adult cohort fully recruited) | 333 randomised |
| Open Label Extension (OLE) | Up to 2 years | Ongoing | 89 enrolled (93% of eligible) |
| Post-Trial Access (PTA) | Not specified | Ethics approval in progress | Follows OLE completion |
Voluntary continuation at this rate is a relevant data point for future regulatory submissions and commercial narratives, reflecting sustained real-world commitment to the program.
ACTION3 program: where things stand and what comes next
The global ACTION3 Phase 3 trial remains ongoing, with the adult cohort fully recruited at 333 patients randomised and dosed across 219 sites in 21 countries, including the United States, Europe, Japan, China, Australia, and New Zealand. The final adult patient commenced treatment in March 2026, with dosing expected to complete in March 2028. The paediatric cohort, enrolling patients aged 12 to 17 years, continues recruiting as an independent cohort within the program.
Following completion of the OLE study, patients will be offered continued access to DMX-200 through the Post-Trial Access (PTA) program, pending ethics approval in each relevant territory. Dimerix and its commercial partners are currently in the process of seeking that approval across territories that recruited ACTION3 patients.
Key upcoming milestones and catalysts for the program include:
- Ongoing ACTION3 adult cohort treatment and follow-up through to March 2028
- Continued OLE enrolment as additional ACTION3 patients complete the blinded phase
- Ethics approval for the PTA program across recruiting territories
- Advancement of DMX-652 into Phase 2 development in acute kidney injury as a secondary pipeline catalyst
The structured progression from Phase 3 through to OLE and then PTA builds a long-term safety database that may serve as a regulatory asset in future approval submissions.
DMX-200’s patent and regulatory foundation
DMX-200 is protected by granted patents in various territories until 2032, with patent applications submitted globally that may extend protection to 2042. The compound holds Orphan Drug Designation in the United States, Europe, the UK, and Japan, providing additional regulatory incentives and market exclusivity pathways in key commercial territories.
Investment thesis: why the four-year milestone matters
The first patient completing four continuous years in the DMX-200 program carries several implications for investors in Dimerix.
Long-term safety data accumulation is among the most consequential outcomes. Four years of continuous patient participation builds the real-world safety dataset that regulators typically require as part of an approval submission for a chronic disease treatment.
Pipeline depth adds a second dimension to the investment thesis. The acquisition of DMX-652 brings a renal asset targeting acute kidney injury, with FDA clearance to proceed with a Phase 2 clinical trial protocol and sufficient pharmaceutical grade (GMP) drug supply in place. This diversifies Dimerix’s development profile beyond ACTION3.
The DMX-652 acquisition, structured at US$5 million upfront against up to US$287 million in potential milestones, added an asset targeting a US$3.5 billion global acute kidney injury market where no approved therapies currently exist and no known clinical-stage competitors have been identified.
Commercial partner network provides global reach. Dimerix has a network of five commercial partners supporting global development and anticipated future market access.
Dimerix’s five commercial partners collectively represent a network spanning the US, Europe, Japan, and Greater China, with the fifth and most recent agreement bringing in a US$10 million upfront payment and up to approximately AU$481 million in total potential deal value from Everest Medicines across the Asia region.
Looking ahead, March 2028 represents the next major program milestone, when the final adult ACTION3 patient is expected to complete dosing. As the announcement notes, this is anticipated to be a major value-creating event if successful, though outcomes remain subject to the inherent uncertainties of clinical development.
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