Dimerix Limited (ASX:DXB) announced a significant regulatory advancement for its lead drug candidate DMX-200, following a Type C meeting with the U.S. Food and Drug Administration (FDA) in March. The FDA has confirmed that proteinuria is an acceptable primary endpoint for full marketing approval in the United States for DMX-200 in treating Focal Segmental Glomerular Sclerosis (FSGS), a rare and progressive kidney disease.
This regulatory decision aligns with Dimerix's previous clinical findings and could potentially accelerate the drug's path to market, providing new hope for patients suffering from this debilitating condition.
FDA Guidance on Trial Endpoints
The FDA specified that suitable proteinuria endpoints could include either a statistically significant increase in the proportion of patients achieving a defined proteinuria reduction compared to placebo after two years of treatment (as proposed by the PARASOL working group), or a statistically significant decrease in proteinuria from baseline compared to placebo after the same treatment period.
For the latter approach, the agency indicated that Dimerix would need to provide data-driven justification for what constitutes a meaningful difference between treatment arms well before the trial's completion.
Additionally, the FDA recommended that if proteinuria is used as the primary endpoint, the existing estimated glomerular filtration rate (eGFR) slope change should be pre-specified as a secondary endpoint. This guidance is particularly favorable for Dimerix, as proteinuria is known to demonstrate less variability than eGFR in clinical trials, potentially reducing risk for downstream marketing approval.
Dr. Nina Webster, CEO and Managing Director of Dimerix, emphasized the significance of this development: "The agreement with the FDA on proteinuria as an appropriate primary endpoint for full marketing approval for DMX-200 in our phase 3 trial is an exceptional outcome, particularly given that DMX-200 has previously demonstrated positive effects on this endpoint in both pre-clinical and clinical studies."
Potential for Accelerated Approval
Importantly, the FDA confirmed they remain open to discussing endpoints that could support a potential Accelerated Approval application and verify clinical benefit. This creates an opportunity for earlier market entry by working with both the PARASOL working group and FDA on an accelerated approval proteinuria endpoint specifically for use in FSGS.
"As part of our study design, both eGFR and proteinuria data are being collected for a total of 2 years; however, the FDA response on proteinuria potentially gives us an opportunity for earlier market entry," Dr. Webster noted.
The ACTION3 Clinical Trial
The ongoing ACTION3 Phase 3 clinical trial is evaluating DMX-200 in patients with FSGS. The trial design includes collection of both eGFR and proteinuria data over a two-year period, positioning Dimerix to potentially leverage this FDA guidance for expedited approval pathways.
FSGS is characterized by scarring in the kidney's filtering units (glomeruli), leading to protein leakage into the urine (proteinuria), kidney damage, and eventually kidney failure. Currently, there are limited treatment options for patients with this condition, highlighting the significant unmet medical need that DMX-200 aims to address.
About Dimerix and DMX-200
Dimerix Limited is an Australian biopharmaceutical company focused on developing innovative therapies for areas with unmet medical needs. Headquartered in Fitzroy, Victoria, the company has a current market capitalization of approximately A$254.5 million and has seen a year-to-date price performance increase of 33.82%.
DMX-200 represents the company's lead clinical asset targeting rare kidney diseases. The drug has previously shown promising results in both pre-clinical models and earlier clinical studies, particularly in reducing proteinuria, which is a key marker of kidney damage in FSGS.
Market Implications
This regulatory development could significantly impact Dimerix's commercial prospects. By potentially shortening the path to market approval through the use of proteinuria as a primary endpoint, DMX-200 could reach patients sooner than initially anticipated.
For patients with FSGS, who currently have few effective treatment options, the advancement of DMX-200 through the regulatory process represents a critical development in addressing this progressive disease.
"There remains a high unmet need for new treatments for this progressive disease, and studies such as ACTION3 provide hope for those patients desperately in need of treatment options," Dr. Webster concluded.
