The treatment landscape for focal segmental glomerulosclerosis (FSGS) is poised for transformation as multiple novel therapies advance through late-stage clinical development, offering hope for patients with this rare and progressive kidney disease that currently lacks FDA-approved, disease-targeted treatments.
A comprehensive pipeline analysis by DelveInsight reveals a robust development space with 12+ active companies working to develop 15+ pipeline FSGS drugs, representing a significant expansion in therapeutic options for this orphan disease. The FSGS market is driven by rising prevalence, limited treatment options, increased recognition as an orphan disease, and ongoing development of novel targeted therapies such as endothelin receptor antagonists and anti-TGF-β agents.
Sparsentan Leads Regulatory Advancement
Travere Therapeutics has achieved a significant regulatory milestone with its dual endothelin angiotensin receptor antagonist sparsentan (Filspari). In May 2025, the U.S. Food and Drug Administration accepted the company's supplemental New Drug Application for traditional approval of sparsentan for FSGS treatment, following positive results from the DUPLEX trial.
The DUPLEX trial (NCT03493685), completed in June 2025, demonstrated that sparsentan resulted in sustained proteinuria reduction among patients with FSGS. This represents a critical advancement for a disease where current treatment relies heavily on supportive care and systemic corticosteroids.
Strong Physician Interest in Emerging Therapies
New data from Spherix Global Insights' seventh annual Market Dynamix FSGS study, surveying 102 U.S. nephrologists in late June 2025, reveals significant unmet medical need and growing enthusiasm for pipeline agents. Only about half of FSGS patients were considered 'optimally managed,' underscoring continued physician reliance on supportive care in the absence of targeted treatments.
Within a competitive field of ten emerging therapies, several candidates are differentiating themselves through targeted mechanisms and potential for genetic subtyping. Many nephrologists indicate they would prescribe leading candidates quickly upon approval, with some considering off-label use in advance of regulatory clearance. Physicians estimate that over 40% of their FSGS patients could be candidates for Filspari, reflecting the drug's potential to impact a broad segment of the population.
Expanding Pipeline Diversity
The current pipeline showcases diverse therapeutic approaches across multiple mechanisms of action. Key pipeline therapies include:
- DMX-200 (Dimerix Bioscience): A Phase III dual angiotensin type 1 receptor and CCR2 receptor antagonist administered orally
- WAL0921 (Walden Biosciences): A Phase II urokinase plasminogen activator receptor antagonist given intravenously
- VAR 200-01 (ZyVersa Therapeutics): A Phase II ATP binding cassette transporter 1 stimulant administered intravenously or subcutaneously
- Brivekimig (Sanofi): Currently in clinical development
Strategic Partnerships Drive Development
The FSGS development landscape has seen significant partnership activity in 2025. In April, Dimerix Limited and Amicus Therapeutics entered into an exclusive license agreement for commercialization of DMX-200 in the United States, while Dimerix retains rights in other territories. Additionally, in January 2025, Dimerix signed an exclusive development and license agreement with Fuso Pharmaceutical Industries for DMX-200 development and commercialization in Japan.
APOL1 Testing Enables Precision Medicine
Growing adoption of genetic testing, particularly for APOL1, is enabling more tailored treatment strategies. Nephrologists view APOL1-positive patients as prime candidates for investigational therapies specifically designed for this population, such as Vertex's inaxaplin. Physicians report a need for more aggressive, targeted, and non-immunosuppressive options in managing APOL1-positive patients.
Steroid-Sparing Approaches Gain Priority
While supportive care with renin-angiotensin-aldosterone system inhibitors (RAASi) and sodium-glucose co-transporter-2 (SGLT2) inhibitors remain foundational, minimizing steroid exposure has become an increasingly important treatment goal. Safety and tolerability concerns continue to drive interest in non-immunosuppressive approaches, particularly for patients facing long-term disease progression and relapse risk.
Critical Period Ahead
As multiple agents advance toward regulatory milestones, including a potential FDA decision for Travere Therapeutics' Filspari in early 2026, the nephrology community is preparing for what could be a much-needed shift in FSGS care. While enthusiasm runs high, nephrologists emphasize that robust clinical evidence—particularly for proteinuria reduction and preservation of estimated glomerular filtration rate (eGFR)—remains the deciding factor for adoption.
As one nephrologist noted, "FSGS needs an FDA-approved targeted therapy that has been clinically shown and proven to actually make a big difference… beyond background therapy." With several promising therapies on the horizon, the next 12 to 18 months could mark the beginning of a new era in FSGS management—one that finally offers patients and physicians a path beyond symptomatic control toward meaningful, disease-modifying outcomes.
