Understanding IgA nephropathy (Berger's disease) — from kidney biopsy and risk assessment through supportive care, disease-modifying therapy (sparsentan, Tarpeyo, Voyxact, Vanrafia), clinical trials, transplant considerations, and living well — personalized information organized by where you are in your journey.
This guide is not medical advice. It is an educational research summary written in plain language, drawn from published medical literature, major clinical trials, and official guidelines. Every important decision must be made together with the patient’s medical team. Nothing here replaces those conversations. The purpose of this guide is to help patients and families walk into those conversations better prepared. This content does not create a doctor-patient relationship. Trouvera’s guides are produced using AI-assisted research synthesis with human editorial review; they are not written by treating physicians. Laws regarding medical information vary by jurisdiction; consult a local licensed professional for advice specific to your situation.
Standard care first. This guide describes standard and emerging evidence-based care for IgA nephropathy. Treatment is individualized based on proteinuria level, eGFR, biopsy findings, and overall clinical context — always confirm current recommendations with your nephrology team.
Safety warning.Diagnosis requires kidney biopsy. IgAN cannot be confirmed without histologic examination showing mesangial IgA deposits on immunofluorescence. Treatment decisions must be based on biopsy-confirmed diagnosis, proteinuria quantification, and eGFR assessment.
Content last reviewed: May 2026 · Based on KDIGO 2025 IgAN/IgAV Guideline · TESTING (systemic steroids) · NEFIGAN/NefIgArd (budesonide/Nefecon/Tarpeyo) · PROTECT (sparsentan/Filspari) · APPLAUSE-IgAN (iptacopan/Fabhalta) · International IgAN Prediction Tool · MEST-C Oxford Classification · FDA Labels · Always verify with your medical team.
⚡ Quick Start — If You Read Nothing Else
The 5 most important things to know right now.
A kidney biopsy is the only way to diagnose IgA nephropathy. No blood test, urine test, or imaging can confirm the diagnosis. Your biopsy report should include Oxford MEST-C scoring, which describes the specific injury patterns in your kidney and helps guide treatment decisions.
Proteinuria is the key target of treatment. Protein in the urine is the strongest predictor of long-term kidney function. Per KDIGO 2025 guidelines, the goal is to get your urine protein below 0.5 g/day — ideally below 0.3 g/day. Even mildly elevated proteinuria (1–2 g/day) significantly increases the risk of kidney failure over years.
Supportive care is the non-negotiable foundation. Before any disease-specific drug, your kidneys need: an ACE inhibitor or ARB at the highest dose you can tolerate, an SGLT2 inhibitor (dapagliflozin or empagliflozin), blood pressure kept below 120/80, and a low-sodium diet. These steps alone can dramatically slow progression.
IgAN treatment has been transformed — five FDA-approved therapies now exist. Targeted-release budesonide (Tarpeyo), sparsentan (Filspari), iptacopan (Fabhalta, approved for IgAN August 2024), atrasentan (Vanrafia, approved April 2025), and sibeprenlimab (Voyxact, approved November 2025) are all available. If your proteinuria remains above 1 g/day after optimizing supportive care, ask your nephrologist about these options.
See a nephrologist with glomerular disease expertise. IgAN is a complex specialist diagnosis. A general nephrologist may be appropriate for ongoing monitoring, but for risk stratification, biopsy interpretation, and disease-modifying therapy decisions, ask for referral to a nephrologist experienced in glomerular diseases. The sooner the better — early intervention protects the most kidney function.
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Understanding IgA Nephropathy (Berger’s Disease)
IgA nephropathy (IgAN), also called Berger’s disease, is the most common primary glomerulonephritis worldwide — a condition in which the immune system’s own antibodies deposit inside the filtering units of the kidneys (the glomeruli) and cause progressive inflammation and scarring. The antibody involved is immunoglobulin A (IgA), a protein that normally protects the lining of the gut and respiratory tract.
In IgAN, a specific form of IgA called galactose-deficient IgA1 (Gd-IgA1) — essentially a structurally abnormal IgA molecule — is recognized as foreign by the immune system. The body makes autoantibodies against it, forming immune complexes that deposit in the mesangium (the connective tissue between the kidney’s tiny blood vessels). This triggers inflammation, injures the filtering membrane, and over time can cause scarring and permanent kidney function loss.
Real reason for hope. For decades, there were no FDA-approved treatments for IgAN. That changed completely between 2023 and 2025. Five disease-modifying therapies are now approved, more are in late-stage trials, and the field’s understanding of the underlying biology has advanced dramatically. Patients diagnosed today have a fundamentally better outlook than those diagnosed ten years ago — provided they receive timely, expert care.
IgAN affects people on every continent, but prevalence varies significantly by ethnicity and geography:
Most common in East Asia — Japan, China, and South Korea have the highest biopsy-proven rates in the world, partly reflecting higher rates of biopsy for even mild abnormalities. It accounts for 30–40% of primary glomerulonephritides in these countries.
Common in Europe — Particularly Scandinavia and Southern Europe. Accounts for 20–25% of primary glomerulonephritides in most European biopsy series.
Less common in sub-Saharan Africa — Likely due to lower rates of kidney biopsy as well as genuine biological differences.
Age and sex: Most often diagnosed in the second through fourth decade of life. Men are diagnosed more often than women (approximately 2:1 ratio), though women appear to progress less quickly on average.
Familial cases: A small percentage (<5–10%) have a family history, suggesting genetic predisposition. Several susceptibility genes have been identified (TNFSF13/APRIL pathway, complement genes).
The current model of IgAN pathogenesis is called the “four-hit hypothesis”:
Hit 1: Overproduction of abnormal Gd-IgA1 (missing sugars on its hinge region), produced by lymphocytes in the tonsils, gut, and bone marrow.
Hit 2: The immune system generates autoantibodies (IgG or IgA) that recognize the abnormal Gd-IgA1 as foreign.
Hit 3: These autoantibodies combine with Gd-IgA1 to form immune complexes that circulate in the bloodstream.
Hit 4: The immune complexes deposit in the mesangium of the kidney’s glomeruli, activating complement and triggering inflammation, which injures the filtration barrier and causes protein to leak into the urine.
This multi-step process explains why newer therapies target different points in the pathway — some reduce IgA production (budesonide targeting gut lymphocytes, sibeprenlimab targeting the APRIL/BAFF signaling molecules that drive IgA production), while others block the downstream inflammation and scarring.
IgAN is highly variable. The spectrum ranges from a benign condition that never significantly affects kidney function to a rapidly progressive form leading to kidney failure within years:
Favorable course (~30–40%): Patients maintain near-normal kidney function for life, particularly those with microscopic hematuria but minimal proteinuria (<0.3–0.5 g/day).
Intermediate course: Gradual decline in eGFR over 10–30 years. Proteinuria between 0.5–3 g/day is the main driver. Regular monitoring and treatment can significantly slow or halt this trajectory.
Unfavorable course (~20–40%): Progress to end-stage kidney disease (ESKD) requiring dialysis or transplant over 20 years. This risk is highest with persistent proteinuria >1 g/day, reduced eGFR at diagnosis, hypertension, and unfavorable Oxford MEST-C scores.
The key insight: proteinuria is modifiable. Getting proteinuria below 0.5 g/day — regardless of how it is achieved — is strongly associated with preserved kidney function long-term. This is exactly why the new disease-modifying therapies matter.
Sometimes IgA deposits in the kidney arise secondary to another disease rather than as a primary kidney disorder. These “secondary” causes must be excluded:
IgA vasculitis (formerly Henoch-Schönlein purpura / HSP) — IgAN that is part of a systemic vasculitis affecting small vessels in the skin, gut, and joints as well as the kidneys. The kidney biopsy looks identical to primary IgAN. More common in children.
Liver disease / cirrhosis — The liver normally clears Gd-IgA1 from the circulation. Cirrhosis impairs this clearance, leading to IgA accumulation in the kidney.
Celiac disease — Gluten sensitivity can drive IgA production in the gut; a gluten-free diet can reduce IgA deposits and proteinuria.
HIV infection
Ankylosing spondylitis and other spondyloarthropathies
Your nephrologist will order appropriate tests to exclude these secondary causes, which can affect treatment decisions significantly.
IgAN is often silent for years. Common presentations include:
Gross hematuria — Episodes of visibly red or brown “cola-colored” urine, often triggered by an upper respiratory infection or vigorous exercise. These episodes are often frightening but rarely indicate an emergency in primary IgAN. They may last 1–3 days and then resolve.
Microscopic hematuria — Blood in urine detectable only on urine dipstick or microscopy. Often found incidentally during a health check-up.
Foamy or frothy urine — A sign of significant proteinuria. The foam is caused by protein in the urine acting like a detergent.
Hypertension — High blood pressure is both a consequence and an accelerator of IgAN-related kidney damage.
Edema (swelling) — Ankle and leg swelling, particularly if proteinuria is in the nephrotic range (>3.5 g/day).
Fatigue and reduced urine output — Symptoms of significantly reduced kidney function.
When to seek urgent attention. Contact your doctor or go to an urgent care if you notice blood in the urine accompanied by severe loin pain, fever, or if it does not resolve within 3–5 days. A sudden and marked reduction in urine output, severe swelling, or significantly elevated blood pressure readings should be evaluated promptly.
Has a kidney biopsy been performed to confirm IgAN? If not, why?
What does my Oxford MEST-C score mean for my prognosis?
Are secondary causes of IgAN (cirrhosis, celiac disease, HIV, IgA vasculitis) being considered?
What is my current proteinuria level, and what is the target?
What is my current eGFR, and what is my estimated eGFR trajectory?
Should I see a nephrologist who specializes in glomerular disease?
What “Most Common Primary Glomerulonephritis Worldwide” Really Means for You
IgAN’s status as the most common primary glomerulonephritis worldwide — affecting an estimated 2.5 million people globally — is both reassuring and practically important for your care. It is reassuring because it means there is a large and growing body of research dedicated specifically to this disease, an active clinical trial ecosystem, FDA-approved therapies for the first time in decades, and nephrologists around the world developing expertise in IgAN treatment. It is practically important because it means you live in a disease category where the treatment landscape is evolving rapidly, specialist expertise exists at major academic medical centers within reach of most US patients (including the University of Utah’s Kidney/Glomerular Disease program and the IgA Nephropathy Foundation’s provider network), and patient advocacy organizations can connect you with research, peer support, and expert clinical consultation. The IgA Nephropathy Foundation (igan.org), the National Kidney Foundation, and the American Kidney Fund all have dedicated IgAN resources — not all kidney disease foundations have disease-specific depth, and IgAN’s prevalence has earned it genuine advocacy infrastructure. The IgAN Society (igansociety.org) maintains the International IgAN Prediction Tool and publishes patient-facing research summaries; registering for their updates ensures you receive information about new approvals and trial openings as they occur rather than discovering them months later.
The most important implication of IgAN’s prevalence for your personal experience is that you are likely to find other patients who share your experience and understand the particular texture of this diagnosis: the alarm of seeing blood in the urine for the first time and not knowing what it meant; the uncertainty of a variable disease course that makes individual prognosis difficult; the transition from a young adult who had never had a health problem to a patient with a chronic condition that requires lifelong monitoring and medication. These experiences are shared by a large community, and connecting with that community — through the IgA Nephropathy Foundation peer navigator program, through condition-specific groups on patient platforms, or through regional kidney disease support groups — provides practical knowledge (how other patients manage REMS programs, how they navigate insurance prior authorization, what they wish they had known at diagnosis) as well as the emotional benefit of not navigating this diagnosis alone. Your nephrologist is your medical expert, but your peer community is often where the practical day-to-day management wisdom lives — and for a disease that will affect your life for decades, both kinds of knowledge matter.
Important disclaimer. This guide is educational and does not replace care from a qualified nephrologist. It cannot diagnose IgAN or recommend a specific treatment for you. Every treatment decision should be made with a clinician who knows your full medical history, biopsy results, and risk profile.
Diagnosis & Biopsy: Confirming IgAN and Assessing Risk
Critical: A kidney biopsy is required to diagnose IgA nephropathy. No combination of blood tests, urine tests, or imaging can confirm this diagnosis. The hallmark finding — mesangial IgA deposits on immunofluorescence staining — can only be seen by examining kidney tissue under a microscope. Oxford MEST-C scoring should be included in every IgAN biopsy report.
A percutaneous kidney biopsy is the standard procedure:
You lie face-down on a procedure table. The skin over the kidney is numbed with local anesthetic.
Using ultrasound guidance, a thin biopsy needle is passed through the skin into the lower pole of the kidney. This takes a small core of kidney tissue about 1–2 cm long.
Two or three passes are usually made. The procedure takes about 30–60 minutes total.
You will typically be observed for 4–6 hours afterward for bleeding. Most patients go home the same day; some stay overnight.
Mild soreness in the flank for a day or two is common. You may notice some blood in the urine immediately after — this usually clears.
Serious complications (significant bleeding requiring transfusion, arteriovenous fistula, organ injury) occur in approximately 1–3% of biopsies at experienced centers.
The kidney tissue is processed in three ways: light microscopy (to see structure), immunofluorescence (to detect IgA and other proteins), and electron microscopy (to see the deposits at nanometer scale). IgAN is diagnosed when IgA is the dominant or co-dominant deposit in the mesangium on immunofluorescence.
The Oxford Classification (MEST-C) assigns a score to five specific histological features, each of which predicts kidney function outcomes independently:
M (Mesangial hypercellularity) — M0 means <50% of glomeruli have mesangial hypercellularity; M1 means ≥50%. M1 is associated with faster progression.
E (Endocapillary hypercellularity) — E0 (absent) or E1 (present). E1 indicates active inflammation inside the glomerular capillaries and may suggest benefit from immunosuppression.
S (Segmental glomerulosclerosis) — S0 (absent) or S1 (present). Scarring within segments of the glomerulus; associated with poorer long-term prognosis.
T (Tubular atrophy / interstitial fibrosis) — T0 (<25%), T1 (25–50%), T2 (>50%). Represents chronic, irreversible injury to tubules. T2 is a strong predictor of poor prognosis regardless of other features.
C (Crescents) — C0 (none), C1 (in <25% of glomeruli), C2 (in ≥25% of glomeruli). Crescents represent active, rapidly destructive inflammation. C2 often triggers consideration of urgent immunosuppression.
How to read a MEST-C report. A score like “M1 E0 S1 T1 C0” means: mesangial hypercellularity present, no endocapillary inflammation, focal scarring present, moderate tubular atrophy/fibrosis, no crescents. Ask your nephrologist to explain your specific scores and what they mean for your treatment plan.
C3 co-deposition: Some IgAN biopsies also show C3 complement deposits alongside IgA. This suggests complement pathway activation and may predict benefit from complement-targeted therapies currently in trials.
After diagnosis, these tests are checked regularly to track your kidney health:
Urine protein-to-creatinine ratio (UPCR) — A spot urine test (first morning urine preferred) that estimates your 24-hour protein excretion. The main treatment target.
24-hour urine collection for protein — A more precise measure of protein excretion, used to confirm UPCR results at key decision points.
Urinalysis with microscopy — Checks for blood and protein in the urine. Dysmorphic red blood cells and red blood cell casts on microscopy confirm glomerular origin of hematuria.
Serum creatinine and eGFR — eGFR (estimated glomerular filtration rate) is the main measure of kidney function. Normal is >90 mL/min/1.73m². Consistent decline in eGFR over time (eGFR slope) is a strong predictor of future kidney failure.
Serum IgA level — Elevated in approximately 50% of IgAN patients, but not specific enough to diagnose or exclude IgAN. Useful as one data point.
Blood pressure at every visit — Hypertension is both a cause and consequence of kidney injury in IgAN. Target <120/80 mmHg per KDIGO 2025.
Complement levels (C3, C4) — Usually normal in primary IgAN. Low complement suggests lupus nephritis or MPGN, and triggers alternative diagnoses.
Electrolytes, serum potassium — Important when on ACE inhibitors, ARBs, or SGLT2 inhibitors.
ANA, ANCA, anti-GBM antibodies — Ordered when secondary causes or overlap syndromes are suspected.
Not all IgAN patients need the same intensity of treatment. Risk stratification helps guide treatment decisions:
The International IgAN Prediction Tool is the most validated risk calculator. It uses your age at biopsy, MEST-C scores, proteinuria, eGFR, blood pressure, and immunosuppression history to estimate your 5- and 10-year risk of a 50% decline in kidney function or ESKD. Ask your nephrologist to calculate this for you.
Key risk factors for faster progression:
Proteinuria >1 g/day (especially >3 g/day) despite supportive care
Reduced eGFR at diagnosis (especially <60 mL/min)
Declining eGFR slope over time
Hypertension
Oxford MEST-C T1/T2 (tubular atrophy/fibrosis) or C2 (crescents)
Male sex
Low-risk patients (proteinuria <0.5 g/day, normal eGFR, no hypertension, favorable histology) may be monitored on optimized supportive care alone without disease-modifying drugs.
What was my Oxford MEST-C score, and what does each component mean for my prognosis?
Was my biopsy processed with immunofluorescence, light microscopy, and electron microscopy?
Has the International IgAN Prediction Tool been used to estimate my risk?
Should I be tested for celiac disease or screened for hepatitis B/C or HIV?
How often should my urine protein and eGFR be checked?
At what proteinuria level or eGFR decline should I start a disease-modifying therapy?
Should I have a repeat biopsy if my condition changes significantly?
Treatment Options: Building the Best Foundation
Supportive care first — always. The KDIGO 2025 IgAN guidelines are explicit: maximize supportive care (RAS inhibition + SGLT2 inhibitor + blood pressure control + sodium restriction) for at least 3–6 months before adding disease-modifying therapy. Supportive care alone can reduce proteinuria by 30–50% and is the non-negotiable foundation for every IgAN patient regardless of risk level.
Understanding the Treatment Philosophy: Protect, Stabilize, and Escalate
The treatment of IgAN follows a three-stage philosophy that your nephrologist applies systematically, and understanding this philosophy helps you become an active, informed partner rather than a passive recipient of prescriptions. Stage one is Protect: regardless of your risk level, every IgAN patient begins with maximizing the protective effect of blood pressure control and the kidney-protecting medications (ACE inhibitor or ARB, SGLT2 inhibitor). These are not weak or temporary treatments — they target the downstream kidney injury directly, reduce protein leak from the glomerulus, and slow the rate at which kidney tissue is damaged. For many patients with mild to moderate IgAN, this protection is sufficient to maintain normal or near-normal kidney function for decades. Stage two is Stabilize: after 3–6 months of maximized supportive care, your nephrologist will formally reassess your proteinuria level. If it has fallen below 0.5–1 g/day, you may remain on supportive care alone with regular monitoring, which avoids the cost and side effects of a biologic medication. If proteinuria remains above 1 g/day despite maximal supportive care, you move to stage three. Stage three is Escalate: add a disease-modifying therapy from the five FDA-approved options, targeting the immune mechanism that is driving the IgA accumulation in your kidney. The escalation decision is based on objective data (your proteinuria level, eGFR trajectory, biopsy findings) rather than symptoms or subjective experience — because IgAN is usually silent while progressing. This is why regular lab monitoring is essential even when you feel well.
The most important single number in your treatment journey is your urine protein-to-creatinine ratio (UPCR), and understanding what it means gives you the ability to gauge your own treatment response. A UPCR of 1.0 g/g means your kidneys are losing approximately 1 gram of protein per day — above the KDIGO 2025 threshold for disease-modifying therapy consideration. A UPCR of 0.5 g/g means 0.5 g/day — the aspirational lower target. A UPCR of 0.3 g/g means 0.3 g/day — the level at which long-term kidney outcomes approach those of the general population in observational studies. The trajectory matters as much as the absolute number: a UPCR falling from 2.0 to 0.8 over 6 months is a positive treatment response even if it has not yet reached the target, while a UPCR stable at 0.8 for 2 years is a plateau that may or may not require further escalation depending on eGFR stability. When you attend your appointments, always ask: “What is my latest UPCR, and is it trending toward the target?” This single question anchors every treatment conversation and ensures you leave each appointment knowing whether your disease is under control.
Step 1: Supportive Care — The Foundation
Renin-angiotensin system (RAS) inhibition is the cornerstone of IgAN management and should be offered to every patient with proteinuria >0.5 g/day:
What they do: ACE inhibitors (e.g., lisinopril, ramipril, enalapril) and ARBs (e.g., irbesartan, losartan, olmesartan) lower blood pressure and independently reduce protein leakage from the kidneys by relaxing the pressure inside the glomerulus.
Target dose: The maximum tolerated dose, not just any dose. Proteinuria reduction is dose-dependent. This means titrating up over weeks until limited by blood pressure, potassium, or creatinine.
ACEi vs. ARB: Similar efficacy. Do not combine ACEi + ARB — dual RAS blockade increases the risk of hyperkalaemia and kidney injury without added benefit.
Important interaction: If you are prescribed sparsentan (Filspari), it acts as an ARB. You must stop your separate ACE inhibitor or ARB — do NOT take sparsentan on top of another RAS inhibitor.
Monitoring: Check potassium and creatinine 1–2 weeks after starting or dose-increasing, and periodically thereafter. A small rise in creatinine (<30%) when starting is expected and usually acceptable.
SGLT2 inhibitors — drugs originally developed for type 2 diabetes — have proven kidney-protective in IgAN and are now part of the KDIGO 2025 standard of care:
Dapagliflozin (Farxiga): The DAPA-CKD trial enrolled 270 IgAN patients. eGFR decline was significantly slower in the dapagliflozin group (–3.5 mL/min/year) compared to placebo (–4.7 mL/min/year) over 2.4 years, with a 71% relative risk reduction in the primary kidney composite endpoint in the IgAN subgroup.
Empagliflozin (Jardiance): The EMPA-KIDNEY trial enrolled 817 patients with IgAN. Results were consistent: slower eGFR decline and reduced risk of kidney disease progression or cardiovascular death.
How they work: Multiple mechanisms including reduced glomerular pressure, anti-inflammatory effects, metabolic benefits, and potentially direct reduction of IgA-driven injury.
Safety: Genital mycotic infections (yeast infections) are the main side effect, especially in women. Rare but serious: diabetic ketoacidosis (even in non-diabetic patients under physiologic stress — hold the medication before major surgery or prolonged fasting). Stay well hydrated.
eGFR threshold: Generally started when eGFR ≥20–25 mL/min/1.73m². Ask your nephrologist about the right time to start or continue as eGFR declines.
Blood pressure target: <120/80 mmHg per KDIGO 2025. Lower BP reduces glomerular pressure and slows progression. Measured at home in the morning before taking medications gives the most useful readings.
Additional antihypertensives: If ACEi/ARB and SGLT2 inhibitor do not achieve the BP target, additional agents (calcium channel blockers, beta-blockers, diuretics) may be added. Coordinate with your nephrologist about which combination is appropriate for you.
Dietary sodium restriction: Target <2 g of sodium per day (<5 g of table salt). High sodium intake blunts the proteinuria-lowering effect of ACEi/ARB therapy. The biggest sources of hidden sodium in the US diet are bread, processed meats, canned soups and vegetables, restaurant food, and condiments.
Practical tips: Cook from scratch when possible, use herbs and spices instead of salt, read nutrition labels (look for sodium <5% daily value per serving), and request low-sodium options at restaurants.
Step 2: Disease-Modifying Therapies — Five Approved Options
If proteinuria remains >1 g/day after 3–6 months of optimized supportive care, KDIGO 2025 supports adding a disease-modifying therapy. Five are FDA-approved as of June 2026 (budesonide-TRF/Tarpeyo, sparsentan/Filspari, iptacopan/Fabhalta, atrasentan/Vanrafia, sibeprenlimab/Voyxact). The best choice depends on your specific situation, risk level, other medications, and insurance coverage — discuss the options with your nephrologist.
Sparsentan is a first-in-class dual endothelin-A receptor / angiotensin II receptor (ETAR/AT1R) antagonist — meaning it blocks both the endothelin and angiotensin signaling pathways that drive kidney inflammation and scarring in IgAN.
Approval: Full FDA approval for IgAN. Also approved for primary focal segmental glomerulosclerosis (FSGS) without nephrotic syndrome (ages 8+) in April 2026.
Evidence: The PROTECT trial enrolled 404 IgAN patients. At 36 weeks, sparsentan 400 mg daily reduced proteinuria by 49.8% versus 15.1% with irbesartan (an ARB). Over 110 weeks, eGFR slope was –3.0 mL/min/year vs –4.2 mL/min/year, a statistically significant and clinically meaningful difference.
Dose: 400 mg once daily orally. No food restrictions.
Critical rule: Sparsentan IS an ARB. You must stop your current ACE inhibitor or ARB before starting sparsentan. Do NOT combine with another RAS inhibitor — this causes dangerous dual RAS blockade.
REMS program: Filspari is dispensed through a Risk Evaluation and Mitigation Strategy (REMS) program for liver-injury monitoring (liver function tests). In a September 2025 update the FDA reduced the required monitoring frequency and removed the previous embryo-fetal (pregnancy-testing) monitoring requirement from the REMS. Your prescribing nephrologist will enroll you. This is a precaution due to rare hepatotoxicity (liver injury) seen with the endothelin-blocking class.
Pregnancy: Sparsentan is teratogenic (causes birth defects). Reliable contraception remains mandatory while on this medication and it must not be used in pregnancy — even though routine pregnancy testing is no longer a REMS requirement, your nephrologist will counsel you on contraception.
Other side effects: Fluid retention, low blood pressure, nasal congestion (related to endothelin blockade). Report significant ankle swelling or weight gain to your doctor.
Tarpeyo is a specially formulated budesonide (a corticosteroid) designed to dissolve in the ileum (the lower small intestine), where the Peyer’s patches — immune clusters in the gut lining that are a major source of abnormal IgA production — are located. It delivers the anti-inflammatory effect locally to the gut before being extensively metabolized by the liver, greatly reducing systemic steroid exposure compared to conventional oral prednisone.
This is NOT the same as systemic prednisone or oral corticosteroids. The systemic side effect profile of Tarpeyo is much more favorable because very little reaches the bloodstream. It should not be confused with traditional steroid therapy.
Evidence: The NefIgArd Phase 3 trial demonstrated significant reduction in proteinuria and slower eGFR decline compared to placebo. Full 2-year NefIgArd data contributed to the full approval in December 2023.
KDIGO 2025 dosing: 16 mg per day for 9 months.
Who benefits most: Patients with persistent proteinuria >1 g/day despite maximal supportive care. KDIGO 2025 recommends considering it alongside (not instead of) supportive care for eligible patients.
Side effects: Because some systemic budesonide is absorbed, you may experience mild Cushingoid effects (weight gain, round face, acne, mood changes) — far less than with oral prednisone but not zero. Do not stop abruptly after a long course without guidance.
Practical note: Capsules must be swallowed whole — do not crush or chew, as this destroys the targeted-release mechanism. Take with or without food but consistently.
Cost and access: A specialty medication. Prior authorization from insurance is typically required. Calliditas Therapeutics has a patient assistance program for eligible uninsured or underinsured patients.
Sibeprenlimab is a monoclonal antibody that blocks APRIL (a proliferation-inducing ligand), a key cytokine that drives the production of Gd-IgA1 by B cells in the mucosa — targeting the disease at its root, upstream of all the downstream injury.
Approval: FDA accelerated approval November 2025 based on proteinuria reduction as a surrogate endpoint. Full approval contingent on confirmatory kidney function data expected 2026.
Evidence: The VISIONARY Phase 3 trial demonstrated a 51.2% reduction in proteinuria at 9 months. Sibeprenlimab-treated patients also had a significantly attenuated eGFR decline compared to placebo during the treatment period.
Dose: 400 mg subcutaneous injection once every 4 weeks. Administered at a clinic or self-injected (training provided).
Mechanism: By blocking APRIL, sibeprenlimab reduces the amount of Gd-IgA1 produced in the first place, reducing the number of pathogenic immune complexes available to deposit in the kidney.
Safety profile: Generally well tolerated in trials. Injection site reactions are the most common side effect. APRIL also plays a role in immune defense; discuss infection risks with your nephrologist, particularly regarding vaccination timing.
Important note: Confirmatory trial data are pending. The accelerated approval pathway means the FDA approved based on surrogate evidence (proteinuria reduction) — confirmation of hard kidney function endpoints is expected.
Atrasentan is a highly selective endothelin-A receptor antagonist. It blocks the ETA receptor, which promotes vasoconstriction and inflammation in the kidney. It has greater selectivity for ETA over ETB than sparsentan, which in theory reduces some of the fluid retention seen with less selective endothelin blockers.
Approval: FDA accelerated approval April 2025 for IgAN.
Evidence: The ALIGN Phase 3 trial: atrasentan 0.75 mg daily reduced proteinuria by 38.1% relative to placebo (–3.1%) at 36 weeks. Week 136 eGFR data are expected in 2026.
Dose: 0.75 mg once daily orally.
Differences from sparsentan: Atrasentan does not block the angiotensin receptor — it can be used with an ACE inhibitor or ARB (unlike sparsentan). However, endothelin A blockade alone means it does not replace RAS inhibition.
Side effects: Fluid retention (edema, weight gain) is the main concern with endothelin A antagonism. Monitoring weight and avoiding high-sodium diet is important. Some patients require a low-dose diuretic. Teratogenic — effective contraception required.
Access note: Accelerated approval — insurance coverage may lag. Discuss with your nephrologist and specialty pharmacy.
The role of systemic corticosteroids (prednisone, methylprednisolone) in IgAN has been substantially reassessed:
High-dose systemic steroids are generally no longer recommended for most IgAN patients. The STOP-IgAN trial and the original TESTING trial (high-dose methylprednisolone) found that while steroids reduced proteinuria, they were associated with significantly more serious adverse events (infections, diabetes, weight gain, bone loss) that offset kidney benefits.
Revised TESTING trial (low-dose protocol): A lower-dose IV methylprednisolone protocol (0.4 mg/kg/day maximum 32 mg/day, with trimethoprim-sulfamethoxazole prophylaxis) showed a more favorable benefit/risk ratio in patients with eGFR ≥30 and proteinuria >1 g/day. This modified protocol is still used in some high-risk patients by specialists.
KDIGO 2025 position: Systemic corticosteroids may be considered only in selected high-risk patients (high proteinuria, rapidly declining eGFR, crescentic disease on biopsy) after maximizing supportive care, using the revised low-dose protocol, and carefully weighing risks. This is a specialist decision.
Mycophenolate mofetil (MMF): Chinese randomized controlled trials have shown benefit in East Asian populations. Western trials (including STOP-IgAN) did not show clear benefit. MMF is sometimes used in East Asian patients or in complex cases, but is not part of standard Western guidelines.
Cyclophosphamide, azathioprine: Not supported by evidence for IgAN outside of crescentic disease. Rarely used.
Iptacopan is an oral small molecule that blocks complement factor B, a key protein in the alternative complement pathway. In IgAN, complement activation (especially the alternative and lectin pathways) amplifies the glomerular inflammation triggered by immune complex deposition. Blocking it earlier in the cascade than prior agents has shown dramatic results.
APPLAUSE-IgAN Phase 3 trial: Final 2-year results published in NEJM in March 2026 demonstrated a 49.3% reduction in the rate of kidney function decline (measured as eGFR slope) compared to placebo. Proteinuria reduction was also significant. This is one of the most compelling eGFR slope results reported in IgAN to date.
Regulatory status:FDA-approved for IgAN since August 2024 (accelerated approval, to reduce proteinuria in adults with primary IgAN at risk of rapid progression); a supplement seeking traditional approval based on the confirmatory eGFR-slope data is planned for 2026. Iptacopan was first approved as Fabhalta for paroxysmal nocturnal hemoglobinuria (PNH) in 2023.
Safety note: Iptacopan carries a Boxed Warning for serious infections caused by encapsulated bacteria (Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae type b). Vaccination against all three before starting (and revaccination as recommended) is required, and the drug is dispensed only through the Fabhalta REMS program. Discuss the vaccination schedule with your nephrologist.
Accessibility now: Available now — iptacopan (Fabhalta) is an FDA-approved IgAN therapy. Ask your nephrologist whether it is appropriate for you, particularly if complement activation is a prominent feature.
There are no head-to-head trials comparing the five approved therapies. Your choice should be individualized based on:
Your current medications: If you are already on an ARB and it is well-tolerated, switching to sparsentan may offer additional benefit by also blocking endothelin. Atrasentan can be added on top of your existing ACEi/ARB. Tarpeyo and Voyxact do not replace RAS inhibition.
Proteinuria level and risk profile: The most dramatic proteinuria reductions in trials were seen with sibeprenlimab (~51%) and sparsentan (~50%). Iptacopan (~38% vs placebo in APPLAUSE-IgAN), atrasentan (~36% placebo-adjusted), and Tarpeyo (variable, ~30–40% in pivotal trial) are also meaningful.
Tolerability and lifestyle: Tarpeyo is oral once daily. Voyxact is a monthly injection. Iptacopan is an oral twice-daily capsule but requires vaccination against encapsulated bacteria (it carries a Boxed Warning for serious infection) and REMS enrollment. Sparsentan is oral but requires REMS enrollment with liver-function monitoring, and is teratogenic so effective contraception is required. Atrasentan is oral but requires sodium restriction and weight monitoring.
Pregnancy plans: Sparsentan and atrasentan are teratogenic and cannot be used if you are pregnant or planning pregnancy. Voyxact data in pregnancy are limited.
Insurance coverage: These are specialty biologics and high-cost medications. Coverage varies. Ask your nephrologist’s office to help with prior authorization, and contact the manufacturers directly about patient assistance programs.
Combination therapy: Trials are underway examining combinations (e.g., Tarpeyo + Voyxact). This is not yet standard of care. Do not combine therapies without specialist guidance.
Am I on the maximum tolerated dose of my ACE inhibitor or ARB?
Should I start an SGLT2 inhibitor (dapagliflozin or empagliflozin)?
What is my current proteinuria, and has it been re-checked after optimizing supportive care?
Which of the five FDA-approved therapies do you recommend for me, and why?
If I start sparsentan, do I need to stop my current ARB?
What does the REMS program for Filspari involve in practice?
Are there patient assistance programs for these medications if my insurance does not cover them?
A remarkable pipeline. IgAN has become one of the most active therapeutic areas in nephrology. Multiple agents targeting different steps of the “four-hit” pathogenesis are in late-stage development, several with results expected in 2026–2027. This is the right time to be asking about clinical trials.
How to Think About Accelerated Approval, Clinical Trials, and Rapidly Evolving Treatment Options
The IgAN treatment landscape is evolving faster than almost any other kidney disease — and faster than your nephrologist can easily track without dedicated effort. Five FDA-approved agents in two years (2023–2025), several more in Phase 3 with approval decisions expected in 2026–2027, and a rich pipeline of mechanistically novel agents: this pace of change is unprecedented in nephrology and reflects the deep scientific understanding of IgAN pathogenesis that has accumulated over the past decade. Understanding how the approval process works helps you evaluate new options as they arrive without either dismissing them as “experimental” or embracing them uncritically as cures. Three of the five currently approved IgAN agents hold accelerated approval — a regulatory pathway that allows the FDA to approve drugs based on a surrogate endpoint (protein in the urine) that is reasonably likely to predict kidney function preservation. This is not a lower standard of evidence, but a different standard: the FDA accepted proteinuria reduction as valid evidence because decades of epidemiological data confirm that sustained proteinuria >1 g/day is a powerful predictor of kidney failure, and that reducing it substantially changes the trajectory. The manufacturers are required to complete follow-up studies confirming that the proteinuria reduction actually translates to preserved eGFR and reduced kidney failure rates (confirmatory trials); these studies are underway for all three agents. If a confirmatory trial fails to show kidney function benefit, the FDA can withdraw the approval — but this has not happened for these IgAN agents, and the early eGFR slope data (particularly iptacopan’s APPLAUSE-IgAN 2-year results showing 49% reduction in eGFR decline rate) are strongly supportive.
Deciding whether to participate in a clinical trial requires weighing several factors that are specific to your situation. Trials offer access to agents that may not be commercially available for 1–3 more years, closer medical monitoring (many trials include visits every 4–8 weeks with comprehensive labs), and the opportunity to contribute to knowledge that will help future patients. The key trade-off is that all trials involve a placebo group (you might receive placebo instead of the investigational drug), you may have to discontinue your current disease-modifying therapy during enrollment (since trials typically require wash-out periods to ensure a clean baseline), and the time commitment for trial visits may be substantial. For high-risk IgAN patients with rapidly declining eGFR or proteinuria >3 g/day who have not achieved an adequate response on currently approved agents, clinical trial enrollment is often the right clinical decision — it provides access to agents with promising mechanisms (like atacicept’s dual BAFF/APRIL blockade or felzartamab’s plasma cell depletion) that may produce deeper or more durable remissions than currently approved options. For stable patients with proteinuria at or near target on an approved agent, the risk of a wash-out period and potential placebo assignment may outweigh the expected benefit of trial participation; continued monitoring on the existing regimen is often the more appropriate choice. The conversation about clinical trial eligibility should be a standing agenda item at your nephrology visits — your eligibility may change as the disease progresses or as new trials with different inclusion criteria open.
Pipeline Agents in Late-Stage Development
Like sibeprenlimab (Voyxact), zigakibart targets APRIL (a proliferation-inducing ligand), blocking the upstream signal that drives Gd-IgA1 production by B cells in mucosal tissue. Two anti-APRIL agents in late development reflects the strong validation of this target.
Evidence: Phase 1/2 trial 100-week data showed sustained proteinuria remission and stable eGFR in treated patients. The durability of the response is particularly encouraging.
Phase 3 BEYOND study: Currently enrolling. Expected to provide definitive eGFR slope and clinical outcome data.
Dose: Subcutaneous 600 mg every 2 weeks (more frequent than sibeprenlimab’s monthly dosing).
Felzartamab targets CD38, a protein expressed on long-lived plasma cells — the cells that continuously produce Gd-IgA1 and autoreactive IgG. By depleting these plasma cells, felzartamab aims to reduce the source of pathogenic IgA at a deeper level than agents that block the signaling molecules that activate B cells.
IGNAZ Phase 2a trial: Demonstrated a 35% reduction in UPCR at month 6 with a favorable safety profile.
Phase 3 PREVAIL trial: Started June 2025, enrolling approximately 454 patients. Primary endpoint expected 2027–2028.
CD38 in context: Daratumumab (anti-CD38) is widely used in multiple myeloma. Experience from oncology has informed the safety understanding of this class.
Narsoplimab is a MASP-2 inhibitor targeting the lectin complement pathway. The ARTEMIS-IgAN Phase 3 trial was terminated in October 2023 for futility — meaning the therapy did not demonstrate the expected benefit in the primary endpoint. Development of narsoplimab for IgAN has been discontinued. This is included here so patients who read earlier information about this agent understand its current status.
ClinicalTrials.gov: Search for “IgA nephropathy” filtered by “recruiting” and your country. Each listing includes eligibility criteria, locations, contact information, and a plain-language description.
IgAN Foundation: The IgA Nephropathy Foundation (igan.org) maintains a trial finder and patient navigator service.
Questions to ask when considering a trial: Is this a placebo-controlled trial (meaning you might not receive the active drug)? What are the time commitments? Are visits covered? Will I need to pause my current medications? What happens to my care after the trial ends?
Expanded access (compassionate use): If you have high-risk IgAN and do not qualify for a trial, ask your nephrologist about expanded access programs for investigational agents (for example atacicept or povetacicept) that are not yet FDA-approved for IgAN.
Kidney transplantation is an excellent treatment for IgAN-related end-stage kidney disease. Important considerations:
When to be referred: Most transplant centers recommend referral when eGFR reaches 20 mL/min/1.73m² or below, or when eGFR trajectory clearly points toward ESKD within 1–2 years. Early referral — not waiting for dialysis — improves outcomes and allows preemptive transplant (transplant before dialysis starts), which has better long-term graft and patient survival.
IgAN recurrence after transplant: IgAN can recur in the transplanted kidney. Histologic (biopsy-proven) recurrence rates are approximately 30–40%; recurrence causing clinically significant graft dysfunction or graft loss is approximately 10%. Recurrence risk appears higher in living-donor vs. deceased-donor transplants (possibly due to longer graft survival).
The original immune defect persists: Because IgAN is driven by the recipient’s own abnormal IgA production, the underlying immune trigger remains after transplant. Discussing post-transplant monitoring and whether disease-modifying therapies might be used after transplant is worth discussing with your transplant team as the field evolves.
Living donor considerations: If you have family members who want to donate, the decision requires careful evaluation. First-degree relatives may have a modestly increased risk of IgAN or urinary abnormalities (genetics play a role, though overtly familial cases are uncommon, <5–10%), so living donor evaluation will screen for subclinical kidney disease (urine tests) before proceeding.
Utah transplant: The University of Utah Health Transplant Services is the regional kidney transplant center. Intermountain Health also performs kidney transplants in Utah.
Am I eligible for any current clinical trials?
Would an investigational agent through a clinical trial (for example atacicept or povetacicept) be appropriate for me?
What is my eGFR trajectory, and when should I start planning for transplant evaluation?
If I receive a kidney transplant, what is the risk of IgAN recurring?
Should I have my family members screened for IgAN if they want to be a living donor?
Are there new therapies being evaluated that might be particularly relevant given my biopsy findings?
Living Well & Caregiver Guide
Your daily choices matter. IgAN is a long-haul condition. Healthy habits, medication adherence, and proactive monitoring are not secondary to drug therapy — they are equal partners in protecting your kidney function over decades.
Lifestyle Interventions That Directly Slow IgAN Progression: The Evidence Behind the Advice
Most kidney disease “lifestyle advice” is generic and unvalidated. IgAN is different: several lifestyle interventions have been shown specifically to affect proteinuria and eGFR trajectory in clinical and observational studies, and your nephrologist’s dietary and lifestyle recommendations are not general health guidance — they are evidence-based components of your kidney protection strategy. The most rigorously evidenced of these is dietary sodium restriction. The mechanism is direct: ACE inhibitors and ARBs work by blocking angiotensin II’s effect on the renal efferent arteriole, reducing intraglomerular pressure and protein leak; high sodium intake activates the aldosterone pathway, increases intraglomerular pressure through a mechanism that partially bypasses the ACEi/ARB block, and directly increases urinary protein loss. In patients on maximum-dose ACEi, adding dietary sodium restriction (<2 g/day) reduces proteinuria by an additional 25–35% on top of the drug effect — a reduction equivalent to adding a second kidney-protective medication at zero cost. This is not an exaggeration: in a study of IgAN patients on stable ACEi therapy, moving from a high-sodium diet (>5 g/day) to a restricted diet (<2 g/day) over 3 months produced a 30% proteinuria reduction without any change in medication. The challenge is that the KDIGO 2025 target of <2 g/day sodium corresponds to the sodium content of approximately 5 g of table salt — a level that requires active engagement with food label reading, reduced restaurant dining, and home cooking rather than processed food. A 24-hour urine sodium measurement at your nephrology appointments is the most objective adherence check available: if your urine sodium is >100 mmol/day (>2.3 g/day), significant dietary modification is still achievable and worth pursuing before adding a new medication.
The cardiovascular-kidney connection in IgAN is more direct than in most kidney diseases, because the intraglomerular hemodynamic damage that drives IgAN progression is the same mechanism responsible for hypertension-induced kidney injury. This means that lifestyle modifications effective for cardiovascular health — sodium restriction, aerobic exercise, weight management, smoking cessation — have genuine, measurable kidney-protective effects in IgAN, not just general health benefits. A 5 mmHg reduction in systolic blood pressure in a hypertensive IgAN patient with a baseline of 140/90 produces an estimated 10–15% reduction in glomerular filtration pressure, with direct implications for protein leak and eGFR slope. Weight loss of 5% of body weight in an overweight IgAN patient with proteinuria is associated with a 20–30% proteinuria reduction independent of blood pressure change, likely through the adipokine and insulin resistance mechanisms that directly influence glomerular permeability. These are meaningful therapeutic effects achievable without a prescription, and they compound with rather than replace pharmacological therapy. The critical insight for patients is that the time they invest in dietary change, exercise, and weight management produces kidney-specific benefits that are additive to every medication they take — making each drug work better by addressing the hemodynamic conditions that amplify drug-resistant injury. This framing is more motivating than generic “healthy lifestyle” advice because it ties the effort directly to a specific kidney outcome the patient cares about.
Sodium restriction (<2 g/day): The single most important dietary change. High sodium directly increases proteinuria and blood pressure, countering the benefit of your medications. Reading food labels is essential — target <5% Daily Value of sodium per serving. Avoid soy sauce, canned goods, deli meats, fast food, and restaurant meals unless specifically low-sodium.
Protein intake: Do not severely restrict protein without specific guidance from your nephrologist or a kidney dietitian. Current evidence supports moderate protein intake around 0.8 g/kg/day in most IgAN patients with preserved eGFR. Very low protein diets are generally reserved for advanced CKD approaching dialysis (eGFR <20–25). Over-restricting protein leads to malnutrition, muscle wasting, and worse outcomes.
Potassium and phosphorus: Become important to restrict as eGFR declines below 30–45 mL/min. Ask your nephrologist if and when you need to address these. A kidney dietitian can provide personalized guidance.
Hydration: Maintain adequate hydration. There is no evidence that drinking large amounts of extra water beyond normal thirst is beneficial in IgAN. Dehydration, on the other hand, can acutely worsen kidney function, especially when taking ACEi/ARB.
Alcohol: Moderate to heavy alcohol consumption is associated with worse kidney outcomes and can raise blood pressure. If you drink, keep it to a minimum.
Ask for a kidney dietitian referral: A registered dietitian with nephrology expertise can create a personalized dietary plan based on your specific lab results, medications, and eGFR. Most nephrology practices can provide a referral.
Regular aerobic exercise is generally encouraged in IgAN and CKD. Benefits include improved blood pressure control, cardiovascular health, weight management, mental health, and possibly slower CKD progression:
Moderate aerobic activity (30 minutes, 5 days per week — walking, swimming, cycling) is appropriate for most IgAN patients with preserved kidney function.
Exercise-induced gross hematuria: Some IgAN patients notice blood in the urine after vigorous exercise. This is a known phenomenon and is generally benign and temporary. However, mention it to your nephrologist if it occurs frequently or does not resolve within 24–48 hours after rest.
Resistance training: Moderate weight training is generally safe and beneficial for muscle preservation and metabolic health. Avoid extreme or prolonged high-intensity activities if your eGFR is significantly reduced (<30), and check with your nephrologist.
As eGFR declines: Adjust exercise intensity based on symptoms (fatigue, fluid retention). A cardiac or nephrology-focused physical therapist can help design a safe program at any stage.
Understand why each medication matters: ACEi/ARB reduces pressure and protein leak. SGLT2 inhibitor adds independent kidney and cardiovascular protection. Blood pressure medications prevent accelerated damage. Disease-modifying therapies reduce the immune injury. Knowing the purpose of each medication improves adherence.
Use pill organizers and alarms: Set up a weekly pill organizer and phone alarms for medication times. Consistency matters more than perfection — if you miss a dose, do not double up; just take the next dose at the scheduled time.
Never stop ACEi/ARB or disease-modifying therapies without telling your nephrologist first. Stopping suddenly can cause a rebound in proteinuria and accelerate kidney injury. If you have side effects, call your doctor — there may be alternatives or dose adjustments.
Sick day rules: During illness causing significant vomiting, diarrhea, or dehydration, temporarily hold your ACEi/ARB and SGLT2 inhibitor (the “sick day rule”) and call your nephrologist. These drugs can reduce kidney blood flow further when you are dehydrated.
Specialty pharmacy relationships: Most disease-modifying therapies for IgAN are distributed through specialty pharmacies. Build a relationship with your pharmacy team — they can manage refills, insurance authorization, and copay assistance programs.
Avoid NSAIDs: Ibuprofen, naproxen, and other non-steroidal anti-inflammatory drugs reduce blood flow to the kidneys and acutely worsen kidney function, particularly when combined with ACEi/ARB. Use acetaminophen (paracetamol) for pain relief instead. Alert every doctor and dentist you see that you have kidney disease and cannot take NSAIDs.
These are the most important numbers to know and track at every visit:
Urine protein-to-creatinine ratio (UPCR): The treatment target. A UPCR of 1.0 g/g roughly corresponds to 1 g of protein per day. Goal: <0.5 g/g (ideally <0.3 g/g) per KDIGO 2025.
eGFR (estimated glomerular filtration rate): A measure of how well your kidneys filter waste. Keep a running record. Single readings matter less than the trend over time. A sustained decline of more than 3–5 mL/min/year is significant and should prompt treatment review.
Blood pressure: Target <120/80 mmHg. Know your numbers at every visit and at home.
Serum potassium: ACEi/ARB and SGLT2 inhibitors can affect potassium levels. Normal range is approximately 3.5–5.0 mEq/L. Very high potassium (>5.5–6.0 mEq/L) can cause dangerous heart rhythm problems.
Hemoglobin: Anemia becomes common as eGFR declines below 30–45 mL/min. Discuss iron studies and erythropoietin-stimulating agents with your nephrologist if hemoglobin is low.
Keep a personal health log or use a patient portal to track your own numbers over time. Being an engaged, informed patient is one of the most powerful things you can do for your own outcomes.
Call your nephrologist’s office (same day or next business day) if you notice:
New or increasing ankle or leg swelling
Foamy or frothy urine (new or worsening)
Blood pressure readings consistently above 150/95 at home
Significant new fatigue or reduced urine output
Blood in the urine not clearing within 3–5 days
Side effects from new medications (rash, unusual fatigue, dizziness)
Go to an emergency room or call 911 if:
You are making very little or no urine for more than 12 hours
Severe shortness of breath or chest pain
Severe hypertension (systolic >180 mmHg) especially with headache, vision changes, or confusion
Signs of infection with high fever while on immunosuppression
Pregnancy requires careful planning in IgAN. Pregnancy is possible in many women with IgAN, but risk varies substantially based on kidney function and proteinuria. This must be a proactive conversation with your nephrologist, not a last-minute adjustment.
Risk stratification before pregnancy: Women with eGFR >60, proteinuria <1 g/day, and well-controlled blood pressure generally tolerate pregnancy well with close monitoring. Women with eGFR <40, proteinuria >3 g/day, or uncontrolled hypertension face substantially higher risks of preeclampsia, premature delivery, and accelerated CKD progression.
Medications that MUST be stopped before conception: ACE inhibitors and ARBs are teratogenic (cause birth defects) and must be stopped before trying to conceive. Sparsentan and atrasentan (both ARB-related) must also be stopped. Tarpeyo (budesonide) data in pregnancy are limited; discuss with your nephrologist. Sibeprenlimab (Voyxact): limited data; discuss individually.
Blood pressure management during pregnancy: Safe antihypertensives in pregnancy include methyldopa, labetalol, and nifedipine. Hydralazine may be used in hypertensive urgency. Your nephrologist and obstetrician should co-manage your blood pressure throughout.
Increased monitoring: Expect more frequent urine protein and blood pressure checks during pregnancy (every 2–4 weeks). Coordinate between your nephrologist and a maternal-fetal medicine (MFM) specialist for high-risk obstetric care.
After delivery: Restart kidney-protective medications promptly postpartum, guided by whether you are breastfeeding (ACEi/ARB generally avoided while breastfeeding).
A diagnosis of IgAN, particularly in your twenties or thirties when you least expect a kidney disease diagnosis, can be emotionally devastating. Depression and anxiety are significantly more common in people with CKD than in the general population.
Acknowledge the emotional weight — Grief, fear about the future, anger, and uncertainty are all valid and expected responses. This is not weakness.
Ask for mental health support — Request a referral to a psychologist or social worker experienced in chronic illness. Many nephrology practices have integrated social workers.
Connect with others who understand — The IgA Nephropathy Foundation has peer support networks and online communities. Meeting others who live well with IgAN is powerfully reassuring.
Stay engaged in your own care — Patients who take an active role in tracking their labs, understanding their condition, and advocating for themselves consistently do better. This guide is a starting point.
Work and disability accommodations: Most people with IgAN can work normally, especially with preserved kidney function. As the disease progresses, accommodations under the ADA may be available (flexible scheduling for appointments, work-from-home options, reduced physical demands). Social work support can help navigate disability applications if needed.
You are an indispensable part of your loved one’s kidney health team. Here is how to make the most impact:
Support dietary changes together: The low-sodium diet is far easier to follow when the whole household adopts it. Learn to cook low-sodium meals, read labels together, and make restaurant choices that fit the diet. Dietary isolation (“you have to eat different food from the rest of us”) undermines adherence.
Help with medication management: Assist with setting up pill organizers, setting medication alarms, and keeping track of specialty pharmacy refills. Many IgAN patients take 5–8 medications daily; system support makes adherence sustainable.
Recognize warning signs early: Learn to notice increasing ankle swelling, new foamy urine, or blood pressure readings creeping up. You may notice these changes before your loved one does.
Attend nephrology appointments when possible: Four ears are better than two. Help write down questions beforehand, and take notes during the visit. Many clinics allow a support person to be present for telehealth appointments too.
Understand the emotional journey: Frustration, fear, and occasional denial are common in chronic illness. Listening without judgment, and gently encouraging engagement with care rather than demanding it, is most effective.
Navigate insurance together: Prior authorization for specialty medications, step therapy requirements, and copay assistance program applications can be daunting. Tackling these as a team reduces the burden. The nephrologist’s office staff are often experienced in these processes and can guide you.
Take care of yourself: Caregiver burnout is real. Maintain your own social connections, seek peer support (organizations like the National Kidney Foundation have caregiver resources), and ask for help when you need it.
Can you refer me to a kidney dietitian for personalized dietary guidance?
What level of exercise is safe at my current stage of kidney function?
Should I hold my ACEi/ARB and SGLT2 inhibitor if I become sick, vomit, or am dehydrated?
Are there NSAIDs or over-the-counter medications I should specifically avoid?
If I am planning a pregnancy, when should I discuss this with you and how far in advance do I need to adjust medications?
Can you refer me to a mental health professional or social worker experienced with chronic kidney disease?
Are there local or virtual support groups for IgAN patients?
Approaches that did not improve outcomes in IgA nephropathy
Understanding de-adopted therapies helps set realistic expectations:
Fish oil (omega-3 fatty acids): Long promoted for IgAN based on the TOMATO trial (Mayo Clinic protocol) showing modest eGFR benefit. The STOP-IgAN trial (2015, Germany) and TESTING trial (2017, China) could not confirm sustained benefit from fish oil alone. Fish oil is no longer recommended as a primary treatment; dietary omega-3 may have modest anti-proteinuric effects but should not replace RAAS blockade or sparsentan.
Tonsillectomy: Widely used in Japan (with apparent reduction in hematuria and proteinuria), but a systematic Cochrane review found insufficient evidence from randomized controlled trials to recommend tonsillectomy for IgAN outside Japan. Not standard of care in North America or Europe.
Systemic corticosteroids alone (high-dose oral prednisone): While the TESTING trial showed benefit for targeted-release budesonide (Nefecon/Tarpeyo), systemic prednisone alone in prior trials (including STOP-IgAN) did not improve renal outcomes and caused significant toxicity (infections, weight gain, diabetes). Indiscriminate use of systemic steroids for IgAN has been de-emphasized.
Azathioprine, mycophenolate mofetil, cyclophosphamide: Multiple small trials and retrospective series suggested benefit, but STOP-IgAN and subsequent meta-analyses showed no robust benefit over optimized supportive care alone and unacceptable infection risk. These immunosuppressants are not first-line for IgAN.
Support & Resources
Utah-specific resources
University of Utah Health — Division of Nephrology, Glomerular Disease Program
The University of Utah has nephrologists with specific expertise in glomerular diseases including IgAN. Comprehensive care including biopsy, all FDA-approved therapies, clinical trial access, transplant services, and transitional care. Phone: 801-581-7742 (Nephrology Clinic). Recommended for: All newly diagnosed or high-risk IgAN patients, patients not meeting proteinuria targets, transplant evaluation, trial interest.
Intermountain Health — Nephrology Services
Nephrology clinics at multiple Intermountain locations across the Wasatch Front. Comprehensive CKD and glomerular disease care. Glomerular disease expertise available — request referral to a nephrologist experienced with IgAN when scheduling.
VA Salt Lake City Health Care System — Nephrology
Nephrology care for veterans. Coordination with University of Utah for advanced therapies, transplant evaluation, and clinical trials when indicated.
IgA Nephropathy Foundation — igan.org
The primary US patient advocacy organization dedicated solely to IgAN. Offers: peer support network, patient navigator service, clinical trial finder, educational webinars, and advocacy for drug access. The best starting point for newly diagnosed patients.
National Kidney Foundation (NKF) — kidney.org
Broad CKD patient resources, community, financial assistance programs (including the NKF HELP program), peer mentoring (NKF Peers), local kidney walks, and advocacy. Helpline: 855-653-2273.
American Kidney Fund (AKF) — kidneyfund.org
Provides direct financial assistance for insurance premiums, copays, and transportation for kidney patients. Kidney health care management and peer coaching programs. Helpline: 800-638-8299.
KDIGO (Kidney Disease: Improving Global Outcomes) — kdigo.org
Publishes the international evidence-based clinical practice guidelines that nephrologists follow. The KDIGO 2025 IgAN guideline is the current standard. Patient summaries of guidelines are also available on the KDIGO website.
The FDA-approved disease-modifying therapies are specialty medications that can cost $50,000–$150,000 annually before insurance. Financial assistance is available — do not let cost be a barrier without exploring all options first:
Filspari (sparsentan) — Travere Therapeutics: Travere SourceConnect patient support program offers prior authorization support, specialty pharmacy coordination, and copay assistance. Contact: 1-833-TRAVERE (1-833-872-8373) or filspari.com.
Tarpeyo (budesonide) — Calliditas Therapeutics: Calliditas patient support program for coverage assistance and copay cards. Contact through your specialty pharmacy or nephrologist’s office.
Voyxact (sibeprenlimab) — Visterra/Otsuka: Patient support services including insurance navigation and copay assistance. Ask your nephrologist’s office or specialty pharmacy for current program details.
Vanrafia (atrasentan) — Novartis: Novartis patient assistance programs. Ask your nephrologist’s office or specialty pharmacy.
Patient Advocate Foundation, HealthWell Foundation, PAN Foundation: Third-party copay assistance funds. Funding availability varies by quarter and diagnosis. Search at patientadvocate.org and healthwellfoundation.org.
Social work services: Nephrology social workers specialize in insurance appeals, prior authorization, disability applications, and financial aid navigation. If your nephrology clinic does not have one, ask for a referral.
ClinicalTrials.gov — clinicaltrials.gov
The official US registry. Search “IgA nephropathy” and filter by “Recruiting.” Each listing shows locations, eligibility criteria, and contact information.
NIH NIDDK — Kidney Disease Research — niddk.nih.gov
The National Institute of Diabetes and Digestive and Kidney Diseases funds IgAN research and maintains patient-friendly kidney disease information.
VALIGA Registry (European) — The largest prospective European IgAN cohort. Research from this registry shapes European and global treatment guidelines.
Japanese IgAN Registry — Japan has the largest national biopsy registry for IgAN and produces important long-term outcome data from the world’s highest-incidence population.
IgAN Foundation trial finder — igan.org — patient-friendly trial search tool with active support for trial matching.
A note on social media and herbal remedies. Online forums and social media contain a great deal of unverified information about IgAN — including claims about herbal treatments, dietary cures, and supplement protocols. No herbal remedy has been proven to modify the course of IgAN in a rigorous clinical trial. Some supplements (high-dose vitamin C, aristolochic acid found in some traditional herbal formulas, and St. John’s Wort) can actually harm kidney function. Always discuss any supplements or non-prescription remedies with your nephrologist before starting them.
Last reviewed May 2026. This guide reflects FDA approvals, clinical trial data, and KDIGO 2025 guidelines current as of May 2026. The IgAN treatment landscape is rapidly evolving. New approvals, updated guidelines, and emerging clinical evidence may change recommendations. Always discuss your specific situation with a qualified nephrologist.
International Approaches
IgAN management varies internationally. Some approaches used routinely in other countries are not standard in the US or KDIGO guidelines. Understanding these differences can be valuable, particularly if you are reviewing international literature or have access to care in multiple countries.
In Japan, tonsillectomy combined with corticosteroid pulse therapy is a distinctive treatment approach for IgA nephropathy, endorsed by the Japanese Society of Nephrology (JSN). The rationale is that the palatine tonsils are a major source of the abnormal Gd-IgA1 that drives the disease. By removing the tonsils and following with intravenous methylprednisolone pulse courses, the aim is to eliminate a key site of pathogenic IgA production while suppressing active glomerular inflammation.
Important context. This approach is not standard in US or KDIGO practice, and the international evidence remains debated. Western nephrologists generally do not recommend tonsillectomy for IgAN outside of Japan. However, some Japanese studies report high clinical remission rates (reduction of proteinuria and hematuria to near-normal levels) when performed early in the disease course, particularly in patients with preserved eGFR and moderate proteinuria. The lack of large, blinded, placebo-controlled trials comparing this approach to modern disease-modifying therapies limits its acceptance outside Japan. Discuss with your nephrologist if you are interested.
Japan operates routine school-based and workplace urinary screening programs that test for hematuria and proteinuria across the entire population. These programs enable uniquely early detection of IgA nephropathy — many Japanese patients are diagnosed at much earlier disease stages than patients in countries without universal screening, where IgAN is often found incidentally or only after significant kidney damage has occurred.
This difference in detection timing has important implications: Japanese clinical outcome data may reflect a milder disease spectrum than Western cohorts, and treatment strategies developed in Japan (including tonsillectomy protocols) are often applied to patients with earlier-stage disease than would typically present for treatment in the US or Europe.
Tarpeyo (budesonide delayed-release capsules, also known as Nefecon) was developed by Calliditas Therapeutics, a specialty pharmaceutical company based in Stockholm, Sweden. The drug’s innovative targeted-release formulation — designed to deliver budesonide specifically to the Peyer’s patches in the ileum, where abnormal IgA is produced — originated from Swedish pharmaceutical science. It became the first FDA-approved disease-modifying therapy specifically for IgA nephropathy (full approval December 2023) and represents a significant contribution from Scandinavian nephrology research to global IgAN care.
Glossary
Plain-language definitions of key terms used throughout this guide.
Gd-IgA1 (galactose-deficient IgA1) — a structurally abnormal form of immunoglobulin A that is missing sugar molecules (galactose) on its hinge region. The immune system recognizes Gd-IgA1 as foreign and forms immune complexes against it, which deposit in the kidney and drive IgAN.
Mesangium — the connective tissue and cells located between the tiny blood vessels (capillaries) inside each glomerulus. In IgAN, immune complexes containing Gd-IgA1 deposit in the mesangium, triggering inflammation and injury.
MEST-C (Oxford Classification scoring) — a standardized pathology scoring system for IgAN kidney biopsies that grades five features: Mesangial hypercellularity (M), Endocapillary hypercellularity (E), Segmental sclerosis (S), Tubular atrophy/interstitial fibrosis (T), and Crescents (C). Each component independently predicts long-term kidney outcomes.
Proteinuria — the presence of excess protein in the urine. In IgAN, proteinuria reflects damage to the kidney’s filtering barrier and is the strongest modifiable predictor of disease progression. The treatment goal is to reduce proteinuria below 0.5 g/day.
UPCR (urine protein-to-creatinine ratio) — a spot urine test that estimates 24-hour protein excretion without requiring a full 24-hour urine collection. A UPCR of 1.0 g/g approximates 1 g of protein per day. First morning urine is preferred for accuracy.
eGFR (estimated glomerular filtration rate) — a calculated measure of how well the kidneys filter waste from the blood, expressed in mL/min/1.73m². Normal is >90. The trend (eGFR slope) over time is more informative than any single reading.
ACEi/ARB — ACE inhibitors (e.g., lisinopril, ramipril) and angiotensin receptor blockers (e.g., irbesartan, losartan). These drugs block the renin-angiotensin system to lower blood pressure and independently reduce proteinuria by relaxing pressure inside the glomerulus. The cornerstone of IgAN supportive care.
SGLT2i (SGLT2 inhibitor) — sodium-glucose cotransporter 2 inhibitors (e.g., dapagliflozin/Farxiga, empagliflozin/Jardiance). Originally developed for diabetes, these drugs provide independent kidney protection in IgAN through multiple mechanisms including reduced glomerular pressure and anti-inflammatory effects.
Complement (C3/C5) — the complement system is a cascade of immune proteins that amplifies inflammation. In IgAN, complement activation (particularly the alternative and lectin pathways, involving proteins like C3 and C5) worsens glomerular injury after immune complex deposition. Several pipeline therapies target complement factors.
APRIL/BAFF — APRIL (a proliferation-inducing ligand) and BAFF (B-cell activating factor) are cytokines (signaling molecules) that stimulate B cells to produce IgA. APRIL is a key target of newer therapies (sibeprenlimab/Voyxact, zigakibart) because blocking it reduces the upstream production of pathogenic Gd-IgA1.
Endothelin receptor — endothelin-1 is a potent vasoconstrictor and pro-inflammatory mediator in the kidney. Endothelin receptor antagonists (sparsentan/Filspari targets ETA+AT1R; atrasentan/Vanrafia targets ETA selectively) block this pathway to reduce inflammation, fibrosis, and proteinuria in IgAN.
Tonsillectomy — surgical removal of the palatine tonsils. In the context of IgAN, this is performed in Japan as part of a combined therapy (tonsillectomy + corticosteroid pulses) based on the rationale that the tonsils are a major source of Gd-IgA1 production. Not standard practice in the US or under KDIGO guidelines.
How to Navigate Specialist Care for IgA Nephropathy
IgA nephropathy is a specialized kidney disease. While your primary care physician or general internist may follow your blood pressure and basic labs, the best outcomes come from care coordinated with a nephrologist experienced in glomerular diseases. Here is a practical guide to getting the right care at the right time.
When to ask for a nephrology referral: If your urine shows persistent blood (hematuria) and/or protein, or if your kidney function (GFR) is declining, your primary care doctor should refer you to a nephrologist. You should not need to wait for your kidney function to fall significantly before getting this referral.
What to bring to your nephrologist: All urine protein measurements (spot urine protein-to-creatinine ratios and 24-hour urine collections), your GFR trend over time, your blood pressure log, your kidney biopsy report if you have one, and a list of all supplements you take (some supplements are nephrotoxic).
Telehealth nephrology: Glomerular disease specialists are concentrated in academic medical centers. Telehealth nephrology consultations with specialists at major centers are increasingly available and allow you to get expert guidance without traveling long distances, especially for treatment decisions or second opinions.
IgA nephropathy patient registry: The University of North Carolina IgA Nephropathy Registry and similar registries allow your data to contribute to ongoing research while connecting you to research teams studying this condition. Ask your nephrologist if enrollment is appropriate for you.
Specialty Centers & Referrals
University of Utah Health — Division of Nephrology, Glomerular Disease Program: Comprehensive nephrology center with expertise in glomerular diseases including IgAN. Services include kidney biopsy, all FDA-approved disease-modifying therapies, clinical trial access, transplant evaluation, and multidisciplinary CKD care. Salt Lake City, UT. · 801-581-7742 (Nephrology Clinic) · healthcare.utah.edu
Intermountain Kidney Services: Nephrology clinics across the Wasatch Front providing CKD and glomerular disease management. When scheduling, request referral to a nephrologist experienced with IgAN and glomerular diseases. Multiple locations throughout Utah and the Intermountain region. · intermountainhealth.org
Mayo Clinic — Division of Nephrology and Hypertension: One of the largest nephrology programs in the US with deep expertise in glomerular diseases. Active IgAN clinical trials, advanced biopsy interpretation, and transplant services. Rochester, MN (also Scottsdale, AZ and Jacksonville, FL). · mayoclinic.org
Columbia University — Center for Glomerular Diseases: A leading academic center specializing in glomerulonephritis including IgAN. Offers expert biopsy review, access to clinical trials, and multidisciplinary glomerular disease clinics. New York, NY. · columbiamedicine.org
Ohio State University — Division of Nephrology: Active glomerular disease program with IgAN expertise, clinical trial participation, and comprehensive CKD management. Columbus, OH. · wexnermedical.osu.edu
University of Toronto — Division of Nephrology: Major Canadian nephrology program with glomerular disease expertise spanning University Health Network and affiliated hospitals. Active in IgAN research and clinical trials. Toronto, ON. · deptmedicine.utoronto.ca/nephrology
Unity Health Toronto — Glomerulonephritis Clinic (St. Michael’s Hospital): A dedicated glomerulonephritis clinic with specific expertise in IgAN and other immune-mediated kidney diseases. Offers comprehensive diagnostic workup, biopsy interpretation, and access to novel therapies. Toronto, ON. · unityhealth.to
KDIGO (Kidney Disease: Improving Global Outcomes): The international body that publishes evidence-based clinical practice guidelines for kidney diseases. The KDIGO 2025 IgAN/IgAV Guideline is the current global standard of care. Patient summaries available at kdigo.org.
ERA (European Renal Association): The leading European professional organization for nephrology. Publishes clinical practice guidelines, supports research, and hosts the annual ERA Congress. Provides educational resources and guideline updates relevant to IgAN care in Europe. era-online.org.
JSN (Japanese Society of Nephrology): Japan’s national nephrology society, which publishes clinical practice guidelines for IgAN that include tonsillectomy + pulse steroid protocols and reflect Japan’s uniquely early-detection population. An important reference for understanding Japan-specific approaches and long-term outcome data from the world’s highest-incidence IgAN population. jsn.or.jp.
Boxed Warning — hepatotoxicity: sparsentan can cause serious liver injury; LFT monitoring is mandatory (monthly for the first 6 months, then every 3 months thereafter); report fatigue, nausea, right upper abdominal discomfort, jaundice, or dark urine immediately
Boxed Warning — embryo-fetal toxicity (REMS program): sparsentan can cause fetal harm; two reliable forms of contraception required for women of childbearing potential; pregnancy testing before starting and monthly during treatment; do not use in pregnancy; male patients with female partners of childbearing potential must also use contraception
Dual ACEi + ARB combination is contraindicated: this combination (e.g., lisinopril + losartan) does not provide additional kidney protection but substantially increases risk of acute kidney injury, hypotension, and hyperkalemia — use one agent only; sparsentan contains both an endothelin receptor blocker and ARB activity so does not combine with standard ARBs
SGLT2 inhibitors (dapagliflozin): genital mycotic infections (yeast infections — common; report and treat promptly; hygiene measures); euglycemic diabetic ketoacidosis (rare but serious — report nausea/vomiting/abdominal pain/confusion even if blood glucose not markedly elevated); hold 48-72 hours before major surgery; volume depletion and orthostatic hypotension; UTI risk
Immunosuppression (corticosteroids for high-risk IgAN): serious infection risk (PCP prophylaxis at higher doses; viral infections can be severe); glucose monitoring for steroid-induced hyperglycemia; osteoporosis protection (calcium + vitamin D); never stop steroids abruptly after prolonged use — adrenal suppression risk
Nephrotoxins to avoid in CKD from IgAN: NSAIDs (reduce kidney blood flow; worsen proteinuria and CKD progression; avoid regular use; use acetaminophen instead); IV contrast (pre-hydration required; inform radiology of CKD); aminoglycoside antibiotics (avoid unless no alternative; dose-adjust to eGFR)
All medications require eGFR-appropriate dose adjustment as kidney function declines — inform all prescribers of current CKD stage