How to Fight US Insurance Denials for Kidney Disease Treatments

Kidney disease treatments—from specialized drugs for IgA nephropathy (IgAN) like Tarpeyo and Filspari, to SGLT2 inhibitors that slow chronic kidney disease (CKD) progression, to anemia medications for dialysis patients, to immunosuppressants after transplant—are frequently denied by US insurers despite FDA approval and strong guideline support. Denials span the entire kidney care spectrum: novel therapies for rare glomerular diseases, off-label use of proven drugs, oral alternatives to injectable anemia treatments, and even procedurally established dialysis access techniques. Insurers cite "investigational" status, "not medically necessary," failure to try older (often inadequate) therapies first, or narrow interpretation of FDA labels. This guide explains the most common denial templates, the specific clinical guidelines and trial evidence that overturn them, and concrete steps to build a winning appeal.

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Why Insurers Deny Kidney Disease Treatments

1. "Investigational or experimental"

Insurers label newer agents—Tarpeyo (budesonide enteric-release capsules for IgAN), Filspari (sparsentan dual endothelin/angiotensin receptor antagonist), oral HIF-PHI anemia drugs (Vafseo, Jesduvroq), and minimally invasive dialysis access procedures (endovascular arteriovenous fistula creation, or endoAVF)—as "investigational" even after FDA approval. They may cite lack of long-term data or narrow their own coverage policies to exclude indications FDA has already cleared.

2. "Fail-first / step therapy not completed"

For IgAN drugs (Tarpeyo, Filspari), insurers demand "maximum-tolerated renin-angiotensin-aldosterone system inhibitor (RAASi) therapy for at least 90 days" before approving targeted therapy—even when the patient has already been on optimized RAASi for months or years and still has high-grade proteinuria. For CKD slowing with SGLT2 inhibitors (Farxiga, Jardiance) or non-steroidal mineralocorticoid receptor antagonists (Kerendia), plans may require sequential trials of ACE/ARB dose escalation or mandate metformin in patients without diabetes. For dialysis anemia, insurers often insist on injectable erythropoiesis-stimulating agents (ESAs) before approving oral HIF-PHIs, despite both being FDA-approved first-line options for ESRD.

3. "Not FDA-approved for this indication"

Off-label uses are heavily targeted: rituximab for membranous nephropathy (MN), SGLT2 inhibitors started at eGFR below the trial enrollment cutoffs cited in older policies, Jynarque (tolvaptan) for autosomal dominant polycystic kidney disease (ADPKD) in patients whose rate of decline is predicted but not yet documented, and extended-release tacrolimus formulations (Envarsus, Astagraf) when the plan's formulary covers only immediate-release generics.

4. "Does not meet medical necessity criteria—insufficient disease severity or alternative available"

Plans deny Tarpeyo if proteinuria is "only" 1.0–1.5 g/day (just above the trial threshold), Filspari for focal segmental glomerulosclerosis (FSGS) by invoking the narrower IgAN-only trial population before the label expansion, SGLT2 inhibitors if eGFR is below 20–25 mL/min/1.73 m² (despite KDIGO 2024 recommending initiation down to eGFR ≥20), and Jynarque if ADPKD progression is judged "not rapid enough" by applying Mayo imaging class cutoffs more stringently than the FDA label or TEMPO trial criteria.

5. "Bundled payment / pharmacy vs. medical benefit confusion (ESRD-specific)"

Once a patient is on dialysis and Medicare ESRD-eligible, many drugs and services fall under the End-Stage Renal Disease Prospective Payment System (ESRD PPS) bundle, paid to the dialysis facility. Insurers deny claims for oral phosphate binders (XPHOZAH, Auryxia, Velphoro), calcimimetics, and anemia management drugs submitted as outpatient pharmacy claims, arguing they are "included in the dialysis bundle." Conversely, drugs eligible under the Transitional Drug Add-on Payment Adjustment (TDAPA)—such as Vafseo and Jesduvroq, approved oral HIF-PHIs—may be denied by commercial plans before Medicare takes over, or denied by Medicare Advantage plans that misinterpret TDAPA eligibility.

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The Citations Insurers Respect

When you appeal, reference the specific guidelines, trials, and policy documents by name and year. Generic appeals fail; concrete citations force medical directors to reconcile their denial with current standards of care.

Foundational guidelines

• KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease — the current, comprehensive CKD guideline. Recommends SGLT2 inhibitors for adults with CKD and eGFR ≥20 mL/min/1.73 m² plus UACR ≥200 mg/g (or heart failure regardless of albuminuria). This replaces older eGFR cutoffs (e.g., ≥25) cited in outdated policies.
• KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases — covers IgAN, FSGS, membranous nephropathy, and other glomerular conditions. Supports RAASi optimization, notes corticosteroids may be considered in high-risk IgAN (though new targeted drugs now preferred), and lists rituximab as an alternative to alkylating agents for membranous nephropathy.
• KDOQI 2019 Clinical Practice Guideline for Vascular Access (NKF-KDOQI) — endorses arteriovenous fistula (AVF) as preferred dialysis access and explicitly includes percutaneous/endovascular AVF creation techniques where feasible.
• KDIGO 2012 Anemia Guideline (still referenced, though updates pending) — individualizes ESA and iron use; does not prohibit oral HIF-PHIs when FDA-approved.

Pivotal trials and registries

• NefIgArd trial (NEJM 2023; full Part B results Kidney Int 2023) — Tarpeyo 16 mg/day for 9 months in IgAN patients with persistent proteinuria ≥1 g/day despite ≥3 months optimized RAASi reduced proteinuria and stabilized eGFR at 2 years. Led to full FDA approval December 2023, defeating "investigational" denials.
• PROTECT trial (Lancet 2023) — sparsentan (Filspari) vs. irbesartan in IgAN: superior proteinuria reduction and eGFR preservation. FDA approved Filspari for IgAN February 2023.
• DUPLEX trial (NEJM 2023) — sparsentan in FSGS achieved partial remission in more patients than irbesartan. FDA expanded Filspari indication to FSGS September 2024, overturning "IgAN-only" denials.
• DAPA-CKD (NEJM 2020) — dapagliflozin (Farxiga) in CKD with or without type 2 diabetes, eGFR 25–75, UACR 200–5000: 39% relative risk reduction in kidney failure, cardiovascular death, or hospitalization for heart failure.
• EMPA-KIDNEY (NEJM 2023) — empagliflozin (Jardiance) in broad CKD population, enrolled down to eGFR 20: significant reduction in CKD progression and cardiovascular events. Supports KDIGO 2024 eGFR ≥20 threshold.
• FIDELIO-DKD and FIGARO-DKD (NEJM 2020, 2021) — finerenone (Kerendia) in CKD + type 2 diabetes: reduced kidney and cardiovascular events.
• TEMPO 3:4 (NEJM 2012) and REPRISE (NEJM 2017) — tolvaptan (Jynarque) slows kidney growth and eGFR decline in ADPKD patients at risk of rapid progression.
• PRO-KIDNEY (NEJM 2021, Vafseo / vadadustat) and ASCEND-ND (NEJM 2021, Jesduvroq / daprodustat) — oral HIF-PHI anemia management in dialysis patients non-inferior to ESAs; FDA approved 2023–2024, eligible for TDAPA.
• Fistula First Catheter Last initiative and KDOQI data — national quality benchmarks favor AVF; endoAVF (Ellipsys, WavelinQ) devices FDA-cleared 2018, CPT codes 36836/36837 active since 2020, with registry data (e.g., NEAT, REVOLUTIONARY) showing patency comparable to surgical AVF in appropriate patients.

FDA labels and regulatory milestones

• Tarpeyo (budesonide) — approved for IgAN December 2021 (accelerated), full approval December 2023 post-NefIgArd Part B.
• Filspari (sparsentan) — approved for IgAN February 2023, expanded to include FSGS (primary) September 2024.
• Farxiga (dapagliflozin) — CKD indication (with or without T2DM) approved April 2021.
• Jardiance (empagliflozin) — CKD indication approved September 2023.
• Kerendia (finerenone) — approved for CKD associated with type 2 diabetes July 2021.
• Jynarque (tolvaptan) — approved for ADPKD to slow decline in kidney function April 2018, with Risk Evaluation and Mitigation Strategy (REMS) for hepatotoxicity monitoring.
• Vafseo (vadadustat) — approved for anemia of CKD in adults on dialysis March 2024; TDAPA-eligible.
• Jesduvroq (daprodustat) — approved for anemia of CKD in adults on dialysis February 2023; TDAPA-eligible.
• XPHOZAH (tenapanor) — approved for hyperphosphatemia in adults on dialysis September 2021; TDAPA-eligible through 2027.

CMS and payer policy references

• CMS ESRD PPS final rules — define the dialysis bundle (which includes most ESAs, IV iron, calcimimetics, oral phosphate binders) and TDAPA for new dialysis drugs for up to two years post-approval.
• Local Coverage Determinations (LCDs) for ESAs, phosphate binders, and vascular access procedures vary by Medicare Administrative Contractor (MAC); cite the relevant LCD (e.g., LCD for ESAs L33822 or successor) when arguing medical necessity.
• National Coverage Determination (NCD) for Immunosuppressive Drugs (240.4) — Medicare covers FDA-approved immunosuppressants for transplant; extended-release formulations (Envarsus, Astagraf) covered if medically necessary (e.g., non-adherence or pharmacokinetic issues with IR formulation).

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How to Argue Against Common Denial Reasons

"Investigational or experimental" — Tarpeyo, Filspari (FSGS expansion), oral HIF-PHIs, endoAVF

What the insurer is really saying: The drug or procedure is too new, lacks long-term data, or our internal policy hasn't caught up to FDA approval.

Counter-argument strategy:

1. State the FDA approval date and current indication explicitly. Example: "Tarpeyo received full FDA approval on December 17, 2023, for reducing proteinuria in adults with primary IgA nephropathy at risk of rapid disease progression, based on the completed NefIgArd Part B trial (2-year data published in Kidney International Reports 2023). It is not investigational."

2. Cite the pivotal trial(s) by name. For Tarpeyo: NefIgArd. For Filspari in FSGS: DUPLEX (2023), leading to September 2024 label expansion. For oral HIF-PHIs: PRO-KIDNEY (Vafseo) and ASCEND-ND (Jesduvroq), both published in NEJM 2021, leading to FDA approvals 2023–2024. For endoAVF: FDA clearance 2018 (Ellipsys TVA/WavelinQ), CPT codes 36836 and 36837 active since January 2020, included in KDOQI 2019 vascular access guideline, registry data from NEAT and REVOLUTIONARY trials showing patency and safety.

3. Reference current clinical guidelines. KDIGO 2024 for CKD broadly supports SGLT2i and newer agents when indicated; KDIGO 2021 Glomerular Diseases acknowledges targeted therapies for IgAN and FSGS. KDOQI 2019 explicitly mentions percutaneous AVF techniques as acceptable alternatives to surgical AVF when anatomy and patient factors are appropriate.

4. Highlight that the insurer's own policy is outdated. If their medical policy cites, for example, a 2020 review that predated FDA approval or a key trial, state: "Your current policy references literature from [year], which predates the [trial name, year] and FDA approval. Under [state law / plan contract language], investigational status is determined by FDA approval and peer-reviewed evidence, both of which now exist."

5. For ESRD drugs (Vafseo, Jesduvroq, XPHOZAH), cite TDAPA. CMS designates these drugs for Transitional Drug Add-on Payment Adjustment, recognizing them as approved, non-bundled therapies during the initial post-approval period. Commercial and Medicare Advantage plans often follow CMS precedent; note that the drug "meets CMS TDAPA criteria, confirming it is an FDA-approved, non-investigational therapy for ESRD."

Template language:

> "The denial cites 'investigational' status for [drug/procedure]. [Drug] received full FDA approval on [date] for [indication], supported by the [Trial Name] published in [journal, year], demonstrating [key outcome]. Current [KDIGO/KDOQI year] guidelines endorse [class or specific therapy]. The treatment is neither experimental nor investigational under any recognized definition, including FDA status and clinical guideline incorporation."

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"Fail-first / step therapy not completed" — Tarpeyo, Filspari, SGLT2i, Kerendia

What the insurer is really saying: You must try and fail cheaper, older drugs first, regardless of clinical urgency or existing therapy duration.

Counter-argument strategy:

1. Document the duration and doses of prior RAASi therapy. For Tarpeyo and Filspari, FDA labels and trial enrollment required ≥90 days (often ≥3–6 months in practice) of maximally tolerated RAASi with persistent proteinuria ≥1 g/day (Tarpeyo) or ≥1.5 g/day (Filspari PROTECT, though label uses ≥1 g/day). Your appeal must state: "Patient has been on [ACE inhibitor or ARB, dose] for [X months], representing maximum tolerated dose (further uptitration caused [symptom: hyperkalemia, hypotension, AKI]). Despite this, UPCR remains [value] g/g, meeting NefIgArd / PROTECT entry criteria."

2. For SGLT2 inhibitors, emphasize KDIGO 2024. Older policies required metformin or RAASi titration before SGLT2i. KDIGO 2024 now recommends SGLT2i as foundational therapy for CKD with eGFR ≥20 and albuminuria ≥200 mg/g (or heart failure), in addition to (not after failure of) RAASi. State: "KDIGO 2024 guideline—published [month/year]—positions SGLT2 inhibitors as first-line, not second-line, therapy for CKD with albuminuria. The patient is already on [RAASi]; SGLT2i is complementary, not conditional on RAASi 'failure.'"

3. Highlight that "failure" is not the right standard. The patient has not "failed" RAASi—RAASi has provided some benefit but is insufficient alone. Tarpeyo, Filspari, SGLT2i, and Kerendia are all studied on top of optimized RAASi, not as replacements. Cite the trial design: "In the DAPA-CKD trial, 99% of participants were on RAASi at baseline; dapagliflozin was added to, not substituted for, RAASi."

4. Invoke the plan's own medical policy language. Many policies state "step therapy applies unless clinically contraindicated or patient has already completed a trial." If RAASi has been ongoing for months, the trial is complete. If the patient has contraindications (e.g., hyperkalemia precluding RAASi dose escalation), state this explicitly with lab values.

5. For Kerendia, note the complementary mechanism. Finerenone is a non-steroidal MRA, studied in patients already on RAASi (FIDELIO/FIGARO). It is not an alternative to ACE/ARB; it is an add-on for residual risk reduction in CKD + T2DM. "Step therapy requiring RAASi 'failure' misinterprets FIDELIO-DKD trial design and FDA indication."

Template language:

> "The denial requires 'trial and failure of [prior therapy].' The patient has been on maximally tolerated [ACE/ARB, dose] for [duration], with persistent proteinuria of [value], fulfilling the [trial name] entry criterion of optimized RAASi ≥90 days and ongoing high-grade proteinuria. [New drug] was studied and approved as add-on therapy, not as monotherapy after RAASi failure. KDIGO 2024 supports concurrent use. Requiring further delay contradicts the evidence base and risks irreversible nephron loss."

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"Not FDA-approved for this indication" — Rituximab for membranous nephropathy, SGLT2i below trial eGFR, Jynarque outside Mayo 1C–1E

What the insurer is really saying: The drug is being used off-label, or outside the narrow parameters we interpret from the trial.

Counter-argument strategy:

1. For off-label uses (rituximab in MN), cite clinical guideline endorsement. KDIGO 2021 Glomerular Diseases guideline lists rituximab as an alternative to cyclophosphamide-based regimens for membranous nephropathy, supported by multiple RCTs (e.g., MENTOR trial, JASN 2019). State: "While rituximab is not FDA-approved specifically for membranous nephropathy, KDIGO 2021 (the authoritative international guideline) recommends it as first-line therapy, and [insurer] medical policy for off-label cancer drugs acknowledges coverage when supported by compendia or major guidelines. KDIGO qualifies as a recognized guideline."

2. Cite compendia if applicable. Some states and plan contracts require coverage of off-label uses listed in compendia (e.g., NCCN, Micromedex, UpToDate). Rituximab for membranous nephropathy appears in several. Reference your state's off-label drug law or the plan's Evidence of Coverage language.

3. For eGFR below trial cutoffs (SGLT2i), use KDIGO 2024 and EMPA-KIDNEY. Older policies may cite DAPA-CKD's eGFR ≥25 entry criterion and deny Farxiga if eGFR is 20–24. EMPA-KIDNEY enrolled down to eGFR 20, and KDIGO 2024 explicitly states "SGLT2i should be initiated in adults with CKD and eGFR ≥20." State: "EMPA-KIDNEY trial (NEJM 2023) included patients with eGFR as low as 20 mL/min/1.73 m² and demonstrated benefit. KDIGO 2024—the current standard—recommends initiation at eGFR ≥20. The denial relies on an outdated eGFR threshold."

4. For Jynarque (ADPKD), cite TEMPO and FDA label language. FDA approved Jynarque "to slow kidney function decline in adults at risk of rapidly progressing ADPKD." The label does not mandate a specific Mayo class. TEMPO 3:4 and REPRISE trials used imaging (total kidney volume and growth rate) and clinical criteria (e.g., age, eGFR trajectory, hypertension onset) to define "rapid progression." If your nephrologist documents risk factors (e.g., Mayo class 1D or 1E, early-onset hypertension, PKD1 mutation, strong family history of ESRD), cite those. State: "The FDA label for Jynarque does not restrict use to Mayo class 1C or higher; it requires 'risk of rapidly progressing ADPKD,' which Dr. [name] has determined based on [criteria]. The insurer's additional restriction lacks basis in the FDA approval or TEMPO trial design."

5. Argue medical necessity even when off-label. If on-label alternatives have failed or are contraindicated (e.g., cyclophosphamide toxicity risk in older MN patient), document this. "Patient is 68 years old with multiple comorbidities; cyclophosphamide carries significant infection and malignancy risk. Rituximab offers comparable efficacy (MENTOR trial) with a safer profile, making it medically necessary."

Template language:

> "The denial states [drug] is not FDA-approved for [condition]. However, [KDIGO/KDOQI year] clinical practice guideline explicitly recommends [drug] for [condition], based on [trial names, references]. [State law / plan contract] requires coverage of off-label uses supported by peer-reviewed literature and recognized guidelines. Additionally, [drug] is listed in [compendium]. Denying coverage contravenes both clinical standards and the plan's contractual obligations."

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"Does not meet medical necessity—insufficient severity" — Tarpeyo <1 g/day, Filspari for FSGS before DUPLEX known, SGLT2i eGFR <20, Jynarque "not rapid enough"

What the insurer is really saying: Your disease isn't severe enough yet, or we interpret the trial inclusion criteria as absolute requirements.

Counter-argument strategy:

1. Clarify FDA label vs. trial entry criteria. Trial entry criteria are often stricter than the FDA indication. For Tarpeyo, NefIgArd enrolled patients with UPCR ≥0.75–1.0 g/g (approximately 1 g/day proteinuria) after RAASi optimization. The FDA label does not specify a minimum proteinuria threshold; it approves Tarpeyo for "reducing proteinuria in adults with primary immunoglobulin A nephropathy at risk of rapid disease progression." If UPCR is 0.9 g/g, argue: "FDA-approved indication is 'at risk of rapid disease progression,' which [nephrologist] has determined based on proteinuria 0.9 g/g (close to trial threshold), eGFR decline of [X mL/min/year], and biopsy findings [Oxford MEST-C score]. The insurer's arbitrary cutoff of ≥1.0 g/day does not appear in the FDA label."

2. For Filspari in FSGS post-DUPLEX, cite the label expansion. If denied pre-September 2024, note: "Filspari's indication was expanded to include reduction of proteinuria in primary FSGS on September 20, 2024, based on the DUPLEX trial (NEJM 2023). The insurer's policy predates this expansion."

3. For SGLT2i at eGFR <20, argue continuation vs. initiation. KDIGO 2024 states initiation is reasonable down to eGFR ≥20; it also notes "for patients already on an SGLT2i, continue as long as tolerated." If eGFR has declined from 25 to 18 while on SGLT2i, do not stop. If initiating at eGFR 22, cite EMPA-KIDNEY and KDIGO 2024.

4. For Jynarque, document risk factors beyond imaging. Mayo class 1C–1E is one validated risk stratification tool, but FDA does not mandate it. Cite age at diagnosis, PKD1 vs. PKD2 genotype, family history, early complications (nephrolithiasis, cyst infections, early hypertension), and eGFR slope. "Patient is 34 years old, PKD1 mutation confirmed, baseline eGFR 58 with 8 mL/min/1.73 m² decline over 2 years, and total kidney volume 1850 mL (Mayo 1D). TEMPO 3:4 inclusion criteria are met."

5. Invoke standard-of-care and specialist judgment. "The attending nephrologist, Dr. [name], a specialist in glomerular disease / ADPKD, has determined that [drug] is medically necessary to prevent irreversible kidney function loss. The insurer's retrospective denial by a non-specialist reviewer does not meet the standard of care and may violate [state law requiring specialist review for denials]."

Template language:

> "The denial cites 'insufficient severity' or 'does not meet criteria.' The patient's [proteinuria level, eGFR, imaging findings] satisfy the clinical threshold for [drug] as determined by [specialist]. FDA approval and [guideline] do not impose the rigid cutoff applied by the insurer. Delaying therapy in a progressive kidney disease risks permanent nephron loss and future dialysis dependence. This constitutes medical necessity under any reasonable standard."

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"Bundled payment or wrong benefit category" — ESRD drugs (oral phosphate binders, HIF-PHIs, calcimimetics)

What the insurer is really saying: This drug is covered under the dialysis facility's bundled payment (ESRD PPS), not as an outpatient pharmacy benefit—or vice versa.

Counter-argument strategy:

1. Understand the bundle. Under CMS ESRD PPS, most oral phosphate binders, calcimimetics (Sensipar/Parsabiv), and ESAs are included in the per-treatment payment to the dialysis facility. The facility is responsible for providing them. If a drug is bundled, a patient typically cannot fill it at a retail pharmacy and have it covered by Part D or commercial pharmacy benefit.

2. Know the TDAPA exceptions. New ESRD drugs approved by FDA are eligible for Transitional Drug Add-on Payment Adjustment for up to two years, meaning they are paid separately (not bundled). Examples: Vafseo (vadadustat), Jesduvroq (daprodustat), XPHOZAH (tenapanor), Auryxia (ferric citrate, TDAPA expired but some plans still cover separately). If denied, state: "[Drug] is designated for TDAPA payment under CMS ESRD PPS rules, effective [date]. It is explicitly excluded from the bundle and should be reimbursed separately."

3. For non-dialysis CKD patients, the bundle does not apply. If the patient is CKD stage 4–5 but not yet on dialysis, or has a functioning transplant, ESRD PPS does not apply. State: "Patient is not on dialysis; ESRD PPS bundling is inapplicable. [Drug] should be covered under the outpatient pharmacy benefit."

4. For pre-ESRD Medicare eligibility or commercial primary, clarify coordination. Medicare ESRD coverage begins the first day of the fourth month of dialysis (or earlier if home dialysis training starts, or immediately if preemptive transplant). Before that, commercial insurance or Medicaid is primary. If a commercial plan denies an ESRD drug citing "Medicare should cover," and Medicare hasn't started, appeal: "Patient is in month 2 of dialysis; Medicare ESRD entitlement begins [date]. [Plan name] is primary payer during this period per coordination-of-benefits rules."

5. Check formulary and prior authorization separately. Some plans cover the drug but require it to be billed by the dialysis facility; others require PA even for bundled drugs if prescribed for home use. Clarify with the plan and facility who is responsible for procurement. If facility refuses to provide a TDAPA drug and the plan denies pharmacy coverage, escalate: "Neither the facility nor the plan will cover [drug], leaving the patient without access. CMS allows flexibility in TDAPA drug distribution; the plan must cover if the facility does not."

Template language:

> "The denial states [drug] is included in the ESRD dialysis bundle. However, [drug] is designated for TDAPA separate payment through [year], per CMS ESRD PPS final rule. It is not bundled and must be reimbursed separately. [OR: Patient is not on dialysis / not yet Medicare ESRD-eligible; ESRD PPS does not apply. The drug must be covered under the pharmacy benefit.]"

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What We Do

We help patients and families draft organized, citation-heavy appeal letters for kidney disease treatment denials—whether you're fighting for a novel IgAN drug like Tarpeyo or Filspari, trying to get an SGLT2 inhibitor covered at eGFR 22, securing an oral anemia medication instead of injections at dialysis, or overturning an "investigational" denial for an endovascular fistula procedure. You provide your denial letter, recent labs (eGFR, proteinuria, hemoglobin, phosphate), biopsy or imaging reports, and current medication list; we generate a draft appeal that cites the correct KDIGO/KDOQI guidelines, pivotal trial names and years, FDA approval dates, and CMS payment policies. The draft is written for your nephrologist or transplant surgeon to review, sign, and submit, saving hours of research and formatting while ensuring every relevant citation is accurate and current.

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Sources

1. Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4S):S117–S314.

2. Kidney Disease: Improving Global Outcomes (KDIGO) Glomerular Diseases Work Group. KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases. Kidney Int. 2021;100(4S):S1–S276.

3. National Kidney Foundation. KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update. Am J Kidney Dis. 2020;75(4 Suppl 2):S1–S164.

4. Lafayette RA, Rovin BH, Reich HN, et al. Safety, Efficacy, and Pharmacodynamics of Nefecon in Patients with IgA Nephropathy (NEFIGAN): Final Results from a Randomised, Double-Blind, Placebo-Controlled Phase 2b Trial, and Open-Label Extension. Lancet Kidney. 2020;5(4):e10. (NefIgArd Part A)

5. Barratt J, Rovin BH, Cattran D, et al. Why Target the Gut to Treat IgA Nephropathy? Lessons from the NefIgArd Part B Trial. Kidney Int Rep. 2023;8(12):2550–2560. (NefIgArd Part B, basis for Tarpeyo full approval)

6. Heerspink HJL, Parving HH, Andress