#Japan #Tokyo #Sparsentan #Renalys Pharma #FSGS

Renalys Pharma Makes Significant Progress with PMDA for Sparsentan Trials

On October 17, 2025, Renalys Pharma, Inc., headquartered in Chuo-ku, Tokyo, announced the finalization of an agreement with Japan's Pharmaceuticals and Medical Devices Agency (PMDA). This agreement paves the way for the initiation of two Phase III clinical trials focusing on Sparsentan, a promising treatment under development for two critical kidney diseases: Focal Segmental Glomerulosclerosis (FSGS) and Alport Syndrome (AS).

Sparsentan: The New Hope for Kidney Disease Patients

Sparsentan (development code RE-021) functions as an oral dual endothelin and angiotensin II receptor antagonist, and it holds significant potential in transforming the treatment landscape for patients suffering from kidney-related ailments. Renalys holds an exclusive license for its development and commercialization across Japan and other regions in Asia.

The clinical trials are designed as multicenter, open-label, non-controlled studies, aiming to evaluate the efficacy of Sparsentan in treating the aforementioned conditions. The company is actively preparing to submit Clinical Trial Notifications to the PMDA, signaling a crucial step toward patient treatment eminence.

Unmet Needs in Kidney Disease

With chronic kidney disease (CKD) and end-stage renal disease (ESRD) representing profound challenges in Japan’s healthcare system, particularly in FSGS and AS, the need for innovative therapies has never been greater.

FSGS is acknowledged as a leading cause of kidney failure. Patients suffering from this condition often transition to ESRD, necessitating regular dialysis. The characterizing features of FSGS include focal and segmental sclerosis of the glomeruli, which severely hampers renal filtration. Moreover, Japan designates FSGS as one of the intractable nephrotic syndromes, which complicates treatment options due to limited available therapies.

Conversely, Alport Syndrome presents a hereditary challenge characterized by symptoms such as hematuria and proteinuria typically starting in childhood, which progressively leads to renal impairment. Due to gene mutations affecting collagen type IV, individuals with Alport Syndrome face a significant risk of progression to end-stage renal disease, especially males during late adolescence. Furthermore, many patients may encounter associated complications such as hearing loss and ocular symptoms.

As a rare disease, Alport Syndrome, similar to FSGS, is currently devoid of established curative treatments, emphasizing the critical need for effective therapeutic advancements.

Previous Milestones and Future Prospects

Renalys recently completed data collection on the primary endpoint for Phase III trials concerning IgA nephropathy in Japan, with anticipated topline results expected in the last quarter of 2025. In 2024, Travere Therapeutics, the entity responsible for developing Sparsentan, received full FDA approval for the treatment of primary IgA nephropathy - a significant endorsement that bodes well for Sparsentan's potential in other indications, including FSGS and AS.

The PROTECT Study, pivotal in showcasing Sparsentan’s efficacy, evidenced substantial reductions in proteinuria and preservation of kidney function, thus reinforcing the promising safety profile of FILSPARI®, the commercial name for Sparsentan in the United States.

Renalys Pharma aims to expedite the delivery of Sparsentan to patients across Japan and Asia, underlining their commitment to improving the lives of those battling kidney diseases. With ongoing studies and further product development, Renalys positions itself as a leader in addressing the unmet medical needs prevalent in renal disease management.

About Renalys Pharma

Renalys Pharma, founded in April 2023 and backed by Catalys Pacific and SR One, stands as a dedicated biopharmaceutical company with a vision of pushing boundaries to deliver revolutionary therapeutics for kidney diseases. Their mission closely aligns with ongoing efforts to reduce “drug loss” in the region, ensuring timely access to critical treatments and improving overall patient outcomes.

For further insights, you can explore their official website Renalys Pharma.