In December 2023, TARPEYO became the first FDA-approved treatment proven to significantly reduce the loss of kidney function in adults with primary IgA nephropathy, marking a turning point for a disease that had gone decades without a single targeted therapy. Developed by Calliditas Therapeutics, the drug had received accelerated approval two years earlier based on its ability to reduce proteinuria, but the full approval confirmed what nephrologists and patients had been waiting for: actual preservation of kidney function over time, demonstrated in the NefIgArd Phase 3 trial of 364 patients. What makes this moment remarkable is not just one drug, but a rapid succession of approvals.
Within roughly three years, four disease-modifying therapies have reached the market for IgA nephropathy, each targeting a different piece of the disease’s complex biology. FILSPARI, FABHALTA, and the newest entry, VOYXACT, have all received accelerated FDA approval, giving patients and clinicians a set of options that simply did not exist before 2021. For the estimated 200,000 Americans living with IgA nephropathy, the most common primary glomerular disease worldwide, this represents a genuine shift from managing symptoms to altering the course of the disease itself. This article covers what each of these therapies does, how they differ in mechanism and evidence, who they may be best suited for, and what limitations patients and caregivers should understand before assuming the problem is solved.
Table of Contents
- What Was the First Disease-Modifying Drug Approved for IgA Nephropathy Treatment?
- How FILSPARI Offers a Non-Immunosuppressive Alternative
- The Complement Pathway — FABHALTA Targets a Different Mechanism Entirely
- VOYXACT and the APRIL Pathway — Comparing the Newest Treatment Options
- What Patients Should Know Before Starting Any IgA Nephropathy Therapy
- Why IgA Nephropathy Matters for Brain Health and Aging
- What Comes Next for IgA Nephropathy Treatment
- Conclusion
- Frequently Asked Questions
What Was the First Disease-Modifying Drug Approved for IgA Nephropathy Treatment?
TARPEYO, a targeted-release formulation of budesonide, holds the distinction of being the first disease-modifying therapy to earn full FDA approval for IgA nephropathy. The drug works by delivering budesonide specifically to the distal ileum, where it acts on the gut-associated lymphoid tissue responsible for producing the abnormal galactose-deficient IgA1 antibodies that drive the disease. This is not the same as taking a standard oral corticosteroid. The targeted delivery is designed to reduce systemic immunosuppressive side effects while addressing the disease at one of its key sources. The path to approval was not instantaneous. TARPEYO first received accelerated approval in December 2021 based on a surrogate endpoint, proteinuria reduction, which the FDA accepted as reasonably likely to predict clinical benefit.
Full approval came on December 20, 2023, after the NefIgArd Phase 3 trial demonstrated that TARPEYO significantly slowed the decline in estimated glomerular filtration rate over two years compared to placebo. For context, prior to this, the standard of care for IgA nephropathy consisted mainly of blood pressure management with renin-angiotensin system blockers, general immunosuppression with uncertain benefit-risk profiles, and watchful waiting. None of those approaches had been shown in a rigorous trial to change the disease trajectory in the way TARPEYO’s data demonstrated. The drug is also approved in Europe under the name KINPEYGO, and its approval set the stage for a broader rethinking of how IgA nephropathy should be treated. However, it is worth noting that TARPEYO is an immunosuppressive therapy, which means it carries the risks associated with immune modulation, including increased susceptibility to infections. Not every patient with IgA nephropathy will be a candidate, and the decision to start treatment requires weighing disease severity against those risks.
How FILSPARI Offers a Non-Immunosuppressive Alternative
FILSPARI, developed by Travere Therapeutics, took a fundamentally different approach. Granted accelerated approval in February 2023 and full approval in September 2024, it became the first and only non-immunosuppressive therapy approved for IgA nephropathy. This distinction matters because many patients and physicians are understandably cautious about long-term immune suppression, particularly in a disease that often affects younger adults who may need decades of treatment. FILSPARI works as a dual endothelin and angiotensin receptor antagonist, blocking two pathways that contribute to kidney damage: endothelin-1 and angiotensin II. It is taken once daily by mouth. The PROTECT Phase 3 study, the largest head-to-head interventional trial ever conducted in IgA nephropathy, demonstrated that sparsentan significantly slowed kidney function decline over two years compared to irbesartan, which was already considered an active comparator rather than a placebo.
That trial design is important because it means FILSPARI did not just beat doing nothing; it outperformed a drug already in wide clinical use for kidney protection. However, FILSPARI is not without limitations. Because it affects the endothelin pathway, there are concerns about fluid retention and potential liver effects that require monitoring. The FDA approved updated REMS labeling in August 2025 to reflect evolving safety data. Patients considering FILSPARI should understand that non-immunosuppressive does not mean risk-free, and that regular lab work and clinical follow-up remain essential. For patients who cannot tolerate immunosuppression or who prefer to avoid it, though, FILSPARI represents a genuinely meaningful option that did not exist a few years ago.
The Complement Pathway — FABHALTA Targets a Different Mechanism Entirely
Novartis entered the IgA nephropathy space with FABHALTA, which received accelerated FDA approval on August 8, 2024. It is the first and only oral complement inhibitor approved for this disease, targeting factor B of the alternative complement pathway. This mechanism is distinct from both TARPEYO’s gut-targeted immunosuppression and FILSPARI’s receptor blockade, reflecting growing scientific understanding that IgA nephropathy involves multiple overlapping biological processes. The complement system is part of the innate immune response, and in IgA nephropathy, inappropriate complement activation on the kidney’s glomerular surface contributes to inflammation and scarring. By inhibiting factor B, iptacopan reduces this complement-driven damage. The APPLAUSE-IgAN Phase 3 study demonstrated that FABHALTA met its primary endpoint of reducing proteinuria in adults with primary IgA nephropathy who are at risk of disease progression.
Confirmatory eGFR data to support full approval was expected in 2025. One practical consideration is that complement inhibition, like any immune-modulating therapy, raises questions about infection risk. Patients on complement inhibitors in other disease settings have sometimes required vaccination against encapsulated bacteria such as meningococcus. Whether similar precautions apply broadly to FABHALTA in the IgA nephropathy population is something clinicians need to evaluate case by case. The drug’s oral formulation is a practical advantage over injectable complement inhibitors used in other kidney diseases, but patients should not assume that an oral drug is inherently gentler. The mechanism carries its own specific risk profile.
VOYXACT and the APRIL Pathway — Comparing the Newest Treatment Options
The most recent addition to the IgA nephropathy treatment landscape is VOYXACT, a humanized monoclonal antibody developed by Otsuka Pharmaceutical that received accelerated FDA approval on November 25, 2025. VOYXACT targets APRIL, a cytokine that drives the production of the pathogenic galactose-deficient IgA1 at the heart of the disease. By binding and blocking APRIL, sibeprenlimab addresses what researchers call the “4-hit” pathogenesis model of IgA nephropathy at one of its earliest steps. The VISIONARY Phase 3 trial enrolled 510 patients and produced striking proteinuria data: a 51 percent placebo-adjusted reduction in proteinuria at nine months, with VOYXACT patients seeing a 50 percent decrease while placebo patients saw a 2 percent increase. Unlike the oral medications, VOYXACT is a self-administered subcutaneous injection given every four weeks at a dose of 400 mg. For some patients, the monthly injection schedule may be preferable to daily pills; for others, it may be a drawback.
Confirmatory eGFR data is expected in early 2026 to support traditional full approval. When comparing across all four approved therapies, the tradeoffs are real. TARPEYO offers proven kidney function preservation but involves immunosuppression. FILSPARI avoids immunosuppression but requires monitoring for endothelin-related effects. FABHALTA targets complement with an oral formulation but still awaits full approval data. VOYXACT shows powerful proteinuria reduction and targets a novel pathway but requires injections and also awaits confirmatory kidney function data. No single drug is the obvious best choice for every patient, and nephrologists are increasingly thinking about these treatments not as interchangeable options but as tools that may eventually be used in combination or sequence depending on a patient’s disease biology.
What Patients Should Know Before Starting Any IgA Nephropathy Therapy
Despite the excitement around four approved therapies, patients need to understand several important caveats. First, two of these drugs, FABHALTA and VOYXACT, still hold accelerated approval status, meaning the FDA granted approval based on proteinuria reduction as a surrogate endpoint. Proteinuria is a reasonable predictor of kidney outcomes, but it is not the same as directly demonstrating preserved kidney function over years. If confirmatory trials fail to show eGFR benefit, the FDA could theoretically withdraw approval. This is not a likely scenario given the data so far, but patients should be aware of the distinction between accelerated and full approval. Second, none of these drugs is a cure.
IgA nephropathy is a chronic condition, and current treatments aim to slow progression rather than reverse existing damage. A patient who has already lost significant kidney function may benefit less than someone treated earlier in the disease course. This raises questions about diagnosis and screening that the nephrology community is still working through, since IgA nephropathy is definitively diagnosed only by kidney biopsy, and many cases go undetected until significant proteinuria or declining function triggers investigation. Third, cost and access remain real barriers. Specialty biologics and novel small molecules carry substantial price tags, and insurance coverage can vary. Patients should work with their nephrology team and, where available, patient assistance programs to understand out-of-pocket costs before committing to a treatment plan. A drug that works brilliantly in a clinical trial does no good if a patient cannot afford to stay on it consistently.
Why IgA Nephropathy Matters for Brain Health and Aging
Readers of a brain health and dementia-focused site may wonder why kidney disease deserves attention here. The connection is more direct than it might seem. Chronic kidney disease is an established independent risk factor for cognitive decline and dementia, including both vascular dementia and Alzheimer’s disease.
The mechanisms include shared vascular damage, chronic inflammation, accumulation of uremic toxins that cross the blood-brain barrier, and dysregulated blood pressure that affects cerebral perfusion. IgA nephropathy, as the most common form of primary glomerular disease, contributes meaningfully to the population burden of chronic kidney disease, particularly among younger adults who face decades of cumulative risk. Preserving kidney function through disease-modifying therapy may therefore have downstream cognitive benefits, though this has not been directly studied in IgA nephropathy trials. For caregivers and families already managing cognitive health concerns, understanding that kidney health and brain health are physiologically linked reinforces the importance of comprehensive medical care that does not treat organ systems in isolation.
What Comes Next for IgA Nephropathy Treatment
The pace of progress in IgA nephropathy therapeutics over the past four years has been extraordinary by any measure. Moving from zero approved disease-modifying therapies to four in roughly three years reflects both improved understanding of the disease and a regulatory willingness to use accelerated approval pathways for conditions with high unmet need. The next frontier is likely combination therapy, using drugs that target different steps in the pathogenesis cascade simultaneously, though clinical data supporting specific combinations is still in early stages.
Researchers are also investigating whether earlier intervention, before significant proteinuria or eGFR decline, could prevent kidney damage rather than merely slow it. Biomarker development, particularly around galactose-deficient IgA1 levels and complement activation markers, may eventually allow for more precise patient selection and monitoring. For the 2.5 to 10 per 100,000 people diagnosed with IgA nephropathy each year worldwide, the landscape today looks fundamentally different than it did even five years ago, and the trajectory suggests further refinement is coming.
Conclusion
The approval of TARPEYO as the first fully FDA-approved disease-modifying treatment for IgA nephropathy in December 2023 marked the end of a long era in which patients had no targeted therapy for the most common primary glomerular disease worldwide. The subsequent approvals of FILSPARI, FABHALTA, and VOYXACT have expanded the options to include non-immunosuppressive, complement-targeting, and APRIL-blocking approaches, each with distinct mechanisms, benefits, and limitations. For the estimated 200,000 Americans living with IgA nephropathy, these therapies represent the difference between passive management and active disease modification. Patients and caregivers should approach these developments with informed optimism.
The drugs are real, the clinical data is substantial, and the options are growing. But no therapy is a cure, costs can be significant, and two of the four approved drugs still await confirmatory kidney function data for full approval. Working closely with a nephrologist to understand individual disease severity, treatment goals, and the tradeoffs of each available therapy remains essential. The era of treating IgA nephropathy as an untreatable condition is over, but the era of truly personalized kidney care is still taking shape.
Frequently Asked Questions
What is IgA nephropathy and how common is it?
IgA nephropathy, also called Berger’s disease, is the most common primary glomerular disease worldwide, with an estimated 200,000 affected individuals in the United States alone. It occurs when abnormal IgA antibodies deposit in the kidneys, causing inflammation and progressive damage. Worldwide incidence ranges from 2.5 to 10 cases per 100,000 people, with higher rates in Asian populations and in males compared to females.
What was the first drug approved specifically to slow kidney function loss in IgA nephropathy?
TARPEYO (budesonide delayed-release), developed by Calliditas Therapeutics, received full FDA approval in December 2023 as the first treatment shown to significantly reduce loss of kidney function in adults with primary IgA nephropathy. It works by delivering budesonide to the gut-associated lymphoid tissue where pathogenic IgA1 is produced.
Is there a non-immunosuppressive treatment option for IgA nephropathy?
Yes. FILSPARI (sparsentan), approved by Travere Therapeutics, is the first and only non-immunosuppressive therapy approved for IgA nephropathy. It received full FDA approval in September 2024 and works by blocking both endothelin and angiotensin pathways rather than suppressing the immune system.
Can IgA nephropathy be cured with these new drugs?
No. Current approved therapies slow disease progression and reduce proteinuria, but they do not cure IgA nephropathy or reverse existing kidney damage. They are disease-modifying, meaning they change the trajectory of the disease rather than eliminate it. Ongoing treatment and monitoring are necessary.
How does kidney disease relate to brain health and dementia risk?
Chronic kidney disease is an established independent risk factor for cognitive decline and dementia. Shared mechanisms include vascular damage, chronic inflammation, buildup of uremic toxins that can cross the blood-brain barrier, and blood pressure dysregulation affecting brain blood flow. Preserving kidney function may therefore support long-term cognitive health.
What is the newest FDA-approved treatment for IgA nephropathy?
VOYXACT (sibeprenlimab), developed by Otsuka Pharmaceutical, received accelerated FDA approval on November 25, 2025. It is a monoclonal antibody that blocks APRIL, a key driver of pathogenic IgA1 production. It is self-administered as a subcutaneous injection every four weeks and showed a 51 percent placebo-adjusted reduction in proteinuria in the VISIONARY Phase 3 trial.
