CSL Vifor and Travere Therapeutics Recognize Updated KDIGO Clinical Practice Guidelines for IgA Nephropathy

FILSPARI® (sparsentan) suggested for IgA Nephropathy patients who are at risk of progressive kidney function loss

ST. GALLEN, Switzerland, and SAN DIEGO, Sept. 26, 2025 /PRNewswire/ -- CSL Vifor and Travere Therapeutics, Inc., (NASDAQ: TVTX) support the recent publication of the updated clinical practice guidelines for the treatment of IgA Nephropathy (IgAN), Kidney Disease: Improving Global Outcomes (KDIGO) 2025 clinical practice guideline for the management of IgA Nephropathy and Immunoglobulin A vasculitis. The updated guidelines define diagnostic criteria, treatment goals and treatment approaches, aiming for progress for people living with IgAN and the clinicians who treat them.

The 2025 update defines remission of proteinuria (<0.5 g/day, or ideally at <0.3 g/day) and slowing eGFR decline as key treatment goals. To achieve these goals, the guidelines recommend a treatment approach with therapies simultaneously targeting IgAN-induced nephron loss and IgA-formation.

Within the guidelines it is mentioned that treatment with FILSPARI® (sparsentan), the only Dual Endothelin Angiotensin Receptor Antagonist (DEARA), may be an appropriate first-line approach to manage the responses of IgAN-induced nephron loss in contrast to the RASi-first approach. The guidelines also highlight FILSPARI as the only therapy with proven efficacy compared to optimized RASi in clinical trials — with more patients enrolled in PROTECT than in all prior RASi trials combined.

"The updated KDIGO guidance represents an important step forward for the IgA Nephropathy community," said Prof. Dr. med. Jürgen Floege, Senior Professor, Div. Nephrology and Clinical Immunology at the University Hospital, RWTH Aachen, Germany. "For patients and clinicians, this provides greater clarity and confidence in navigating treatment decisions, with the ultimate goal of improving long-term kidney outcomes."

"The new IgA Nephropathy management recommendations provide important guidance for clinicians treating this rare disease. The inclusion of FILSPARI in the KDIGO guidelines is a reflection of its benefit-risk profile and reinforces its role in helping eligible patients reduce proteinuria and slow kidney function loss, while being generally well-tolerated", said Dr. Achim Obergfell, Global Medical Head Nephrology Portfolio CSL Vifor.  "The updated KDIGO guidelines mark an important milestone for the IgA nephropathy community, reflecting advances in disease understanding, more sophisticated risk assessment and therapies," said Jula Inrig, M.D., chief medical officer of Travere Therapeutics. "The placement of FILSPARI underscores the strong clinical evidence supporting its role as a foundational treatment and offers clinicians with clear, evidence-based guidance to improve patient care."

The now published KDIGO clinical practice guidelines represent a focused update of Chapter 2: IgA Nephropathy/IgA Vasculitis from the KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases. It sets out to provide a comprehensive and evidence-based framework for healthcare professionals to diagnose, treat, and manage these two types of glomerular diseases. The full guidance was presented at the International Symposium of IgA Nephropathy in September 2025 and will be published as a supplement to the Official Journal of the International Society for Nephrology.

FILSPARI is a non-immunosuppressive therapy for the treatment of IgA Nephropathy approved in the United States (U.S.) and Europe, and in addition to the U.S. has been launched in Germany, Austria, Switzerland, Luxembourg and UK.

About the PROTECT Study

The PROTECT Study is one of the largest interventional studies to date in IgA nephropathy (IgAN) and the only Phase 3 head-to-head trial in this rare kidney disease. It is a global, randomized, multicenter, double-blind, parallel-arm, active-controlled clinical trial evaluating the safety and efficacy of 400 mg of FILSPARI (sparsentan), compared to 300 mg of irbesartan, in 404 patients ages 18 years and up with IgAN and persistent proteinuria despite receiving at least 50% of max label dose and maximally tolerated ACE or ARB therapy.

The trial met the pre-specified primary endpoint which showed that after 36 weeks patients receiving FILSPARI (n=202) achieved a mean reduction in proteinuria from baseline of 49.8%, compared to a mean reduction in proteinuria from baseline of 15.1% for irbesartan-treated patients (n=202, p<0.0001). In the final analysis conducted after two years, FILSPARI reduced the rate of decline in kidney function from baseline to Week 110 compared to irbesartan. Treatment emergent adverse events were well-balanced between FILSPARI and irbesartan, except for dizziness and hypotension. 

About CSL Vifor

CSL Vifor is a global partner of choice for pharmaceuticals and innovative, leading therapies in iron deficiency and nephrology. We specialize in strategic global partnering, in-licensing and developing, manufacturing and marketing pharmaceutical products for precision healthcare, aiming to help patients around the world lead better, healthier lives. Headquartered in St. Gallen, Switzerland, CSL Vifor also includes the joint company Vifor Fresenius Medical Care Renal Pharma (with Fresenius Medical Care). The parent company, CSL ((ASX:CSL, OTC:CSLLY), headquartered in Melbourne, Australia, employs 29,000+ people and delivers its lifesaving therapies to people in more than 100 countries.

For more information about CSL Vifor, visit CSL.com.

About Travere Therapeutics

At Travere Therapeutics, we are in rare for life. We are a biopharmaceutical company that comes together every day to help patients, families and caregivers of all backgrounds as they navigate life with a rare disease. On this path, we know the need for treatment options is urgent – that is why our global team works with the rare disease community to identify, develop and deliver life-changing therapies. In pursuit of this mission, we continuously seek to understand the diverse perspectives of rare patients and to courageously forge new paths to make a difference in their lives and provide hope – today and tomorrow. For more information, visit travere.com.

About IgA Nephropathy

IgA Nephropathy, also called Berger's disease, is a rare progressive kidney disease characterized by the abnormal buildup of immunoglobulin A (IgA), an antibody that helps the body fight infections, in the kidneys. The deposits of IgA cause a breakdown of the normal filtering mechanisms in the kidney, leading to blood in the urine (hematuria), protein in the urine (proteinuria) and a progressive loss of kidney function. Other symptoms of IgA Nephropathy may include swelling (edema) and high blood pressure.

While rare, IgA Nephropathy is the most common type of primary glomerular disease worldwide and a leading cause of kidney failure. IgA Nephropathy is estimated to affect more than 250,000 people in the licensed territories.

About FILSPARI (sparsentan)

FILSPARI is an innovative, non-immunosuppressive, single-molecule, dual endothelin angiotensin receptor antagonist (DEARA) with high selectivity for the endothelin A receptor (ETAR) and the angiotensin II subtype 1 receptor (AT1R).

FILSPARI was developed by Travere Therapeutics and has been granted Orphan Drug Designation for the treatment of IgA Nephropathy in the UK, Europe and the U.S. FILSPARI is currently available in the U.S. and first markets in Europe. CSL Vifor has been granted exclusive commercialization rights for FILSPARI in Europe, Australia, New Zealand and certain other countries.  For more information, please refer to the Summary of Product Characteristics (SmPC).

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SOURCE Vifor International AG (CSL Vifor)