Voyxact (sibeprenlimab)
An approved treatment for IgA Nephropathy.
The same compound appears under different names depending on the context. Here is how to identify Sibeprenlimab wherever you encounter it, plus the key facts at a glance.
- Generic name
- Sibeprenlimab
- Brand name
- Voyxact
- Drug class
- APRIL antagonist
- Manufacturer
- Otsuka Pharmaceutical
- How it's taken
- Voyxact is given as a 400 mg injection under the skin once every 4 weeks from a single-dose prefilled syringe, by the patient or a caregiver at home after training.
The first APRIL-blocking antibody approved for IgA nephropathy. It has accelerated approval to lower urine protein in adults with primary IgA nephropathy who are at risk of their disease getting worse; it is not yet known whether it slows the loss of kidney function over time. Sibeprenlimab reduces kidney-damaging IgA antibody production by blocking a key immune signal called APRIL.
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Where Sibeprenlimab fits
First APRIL-targeting therapy for IgA nephropathy, addressing the upstream immune signal that drives production of pathogenic IgA1 antibodies. A mechanistically distinct option from complement inhibitors and endothelin antagonists.
How Sibeprenlimab works
Sibeprenlimab blocks a protein called APRIL that tells your immune cells to produce antibodies. In IgA nephropathy, APRIL drives overproduction of defective IgA antibodies that damage kidneys. By blocking this signal at the source, sibeprenlimab reduces the amount of harmful antibodies reaching your kidneys.
Mechanism: First-in-class APRIL (A-Proliferation-Inducing Ligand) antagonist that blocks APRIL signaling through BCMA and TACI receptors
Side effects and safety
The most common side effects in the main trial were infections (49% vs 45% on placebo), most often upper respiratory infections such as colds (15% vs 14%), and injection site reactions (24% vs 23%), most often redness. Most were mild or moderate. Because it lowers antibody production, it can raise the risk of infections, so your doctor will check for infections before you start and watch for signs of infection during treatment. Live vaccines are not recommended within 30 days before starting or during treatment.
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Sibeprenlimab
Voyxact is given as a 400 mg injection under the skin once every 4 weeks from a single-dose prefilled syringe, by the patient or a caregiver at home after training. Injections go in the front of the thigh or the belly, and a caregiver can also use the back of the upper arm. If a dose is missed, give it as soon as possible and then go back to every 4 weeks[1].
Availability and cost
Only available as the brand-name product.
First-in-class APRIL antagonist for IgA nephropathy. Novel biologic targeting a newly validated pathway in a rare kidney disease with limited treatment options.
Help paying for Voyxact
Pick your insurance to see which help fits. Drugmaker copay cards can't be used with Medicare, Medicaid or TRICARE; charity funds are the usual route there.
- Copay help
VOYXACT Copay Program: eligible commercially insured patients may pay as little as $0; annual maximum benefit applies. No copay card needed.
For: private insurance · source - Bridge or quick-start supply
VOYXACT Bridge Program: commercially insured patients facing a coverage delay may get up to three 28-day supplies at no cost.
For: private insurance · source - Insurance and case manager help
An Otsuka Care Navigator provides education and help getting started, including using the prefilled syringe.
The official page does not say who qualifies. Ask the program. · source - Free medicine program
Otsuka Patient Assistance Foundation lists VOYXACT among medications it provides free to eligible uninsured or underinsured patients.
For: no insurance, underinsured · source
Good to know: Copay and bridge programs exclude Medicare, Medicaid, VA, DoD, TRICARE and other government programs. Free drug is through the separate Otsuka Patient Assistance Foundation (1-855-727-6274).
- From a charity · NORD RareCareIgA Nephropathy Medical Assistance fundOpen
Pays for: Medical and medication costs.
The foundation says: “Accepting new applications and re-enrollments for current year” - From a charity · NORD RareCareIgA Nephropathy Premium Copay Assistance fundOpen
Pays for: Insurance premiums and copays.
The foundation says: “Accepting new applications and re-enrollments for current year” - From a charity · The Assistance FundImmunoglobulin A Nephropathy (IgAN) fundOpen
Pays for: Copays, coinsurance, deductibles and other health-related expenses.
The foundation says: “OPEN — Accepting New Patients. TAF is currently accepting new patient enrollments for this program.” - From a charity · IgA Nephropathy FoundationIgA Nephropathy Foundation Patient Aid Grant fundApply directly
Pays for: Out-of-pocket medical costs and non-medical costs of treatment such as childcare or transportation (Foundation membership required).
The foundation says: “Status not shown on page”
How IgA nephropathy treatments compare
As of 2026, five FDA-approved medicines are available for IgA nephropathy, plus active investigational programs. The right choice depends on your proteinuria level, kidney function (eGFR), prior treatments, biopsy findings, and personal preferences around oral pills versus injections. Your nephrologist will help match a treatment to your specific situation. This chart compares the practical differences between options.
5 FDA-approved iga nephropathy treatments are available: Tarpeyo (budesonide (delayed release), approved 2021); Filspari (sparsentan, approved 2023); Fabhalta (iptacopan, approved 2024); Vanrafia (atrasentan, approved 2025); Voyxact (sibeprenlimab, approved 2025); BHV-1400 (BHV-1400, Phase 1). Tarpeyo is typically used as standard corticosteroid considerations apply (immunosuppression, infection risk, glucose changes); first disease-modifying therapy approved specifically for igan.
| Drug | What makes it different | How it works | How it’s given | How often | Where you get it | Safety highlights | FDA approved |
|---|---|---|---|---|---|---|---|
Tarpeyo budesonide (delayed release) | Targets the disease at its source in the gut | Targeted-release corticosteroid that suppresses Gd-IgA1 antibody production in gut-associated lymphoid tissue (Peyer’s patches) | Oral capsule (taken on an empty stomach) | Once daily | Home (specialty pharmacy delivery) | Standard corticosteroid considerations apply (immunosuppression, infection risk, glucose changes); first disease-modifying therapy approved specifically for IgAN | 2021 |
Filspari sparsentan | Dual ETA + AT1 receptor block in one pill (non-immunosuppressive) | Dual endothelin-A and angiotensin-II AT1 receptor antagonist that reduces glomerular pressure and proteinuria | Oral tablet (REMS program) | Once daily | Home (REMS-certified specialty pharmacy) | Boxed warnings for hepatotoxicity and major birth defects; monthly liver enzyme monitoring; confirmed contraception required (pregnancy contraindicated) | 2023 |
Fabhalta iptacopan | First oral complement inhibitor for IgAN | Selective oral inhibitor of complement factor B that blocks alternative-pathway activation driving kidney inflammation | Oral capsule (REMS program) | Twice daily | Home (REMS-certified specialty pharmacy) | Boxed warning for serious encapsulated-bacteria infections; meningococcal, pneumococcal, and Hib vaccinations required at least 2 weeks before starting | 2024 |
Vanrafia atrasentan | Selective ETA blocker, no REMS or routine liver monitoring required | Selective endothelin-A receptor antagonist that reduces glomerular hypertension and fibrosis | Oral tablet (no REMS required) | Once daily | Home (specialty pharmacy delivery) | Boxed warning for major birth defects (pregnancy contraindicated); contraception required during and for 2 weeks after treatment; warnings include hepatotoxicity, fluid retention, and decreased sperm counts | 2025 |
Voyxact sibeprenlimab You are here | First APRIL antagonist; self-injected at home once a month | Monoclonal antibody that blocks APRIL signaling, reducing B-cell production of pathogenic Gd-IgA1 antibodies | Subcutaneous injection (self-administered, no REMS required) | Every 4 weeks | Home (after training from care team) | Routine vaccinations should be up-to-date before starting; live vaccines avoided during treatment; immunoglobulin levels are monitored periodically | 2025 |
BHV-1400 BHV-1400 | Selectively removes only the disease-driving antibody; spares normal immunity | TRAP degrader that selectively binds Gd-IgA1 and routes it to the liver for clearance, sparing normal antibodies | Subcutaneous injection | Phase 1 expansion cohort enrolling IgAN patients; pivotal regimen TBD | Clinical trial site only (not commercially available) | Investigational — Phase 1 healthy-volunteer single-dose data showed up to 81% Gd-IgA1 reduction; spares normal IgA, IgG, IgE, and IgM; pivotal trial planned for 2026 | Phase 1 |
This chart compares FDA-approved IgA nephropathy treatments and one advanced investigational program (BHV-1400). It is not medical advice. All approved IgAN therapies require background renin-angiotensin system (RAS) blockade with an ACE inhibitor or ARB, and many patients also take an SGLT2 inhibitor. Treatment selection should be made with your nephrologist based on your kidney function, biopsy results, proteinuria level, comorbidities, and prior therapies.
Clinical trial results
The Phase 3 VISIONARY trial enrolled 510 adults with IgA nephropathy. In an interim analysis of the first 320 patients, sibeprenlimab achieved a 51% placebo-adjusted reduction in proteinuria at 9 months, with the treatment group showing a 50% reduction vs. a 2% increase in the placebo group[1]. The FDA granted accelerated approval on November 25, 2025. In August 2026, Otsuka reported 2-year results: kidney function (eGFR) held steady with sibeprenlimab, a slope of +0.3 points a year versus -4.2 on placebo (p<0.0001). Otsuka has started a rolling application to the FDA for traditional (full) approval. Until the FDA acts, Voyxact stays on accelerated approval[2].
Development history
Developed by Otsuka Pharmaceutical, sibeprenlimab received FDA accelerated approval on November 25, 2025, based on proteinuria reduction as a surrogate endpoint. Otsuka has since begun a rolling submission for traditional approval using 2-year kidney function data[2]. It is the first APRIL-targeting therapy approved for any kidney disease.
Explore IgA Nephropathy trials
Other IgA Nephropathy treatments
Sibeprenlimab in Trial Friend News and Guides
- Atacicept vs Povetacicept for IgA Nephropathy Before the FDA Decision on November 30thSeptember 29, 2026
- A Quiet Crisis in Rare Disease Research: Trial Enrollment Is Slowing Just as Treatments Start WorkingApril 13, 2026
- From Zero Treatments to 5 in 3 Years: The IgA Nephropathy Breakthrough Nobody Saw ComingMarch 31, 2026
Common questions about Sibeprenlimab
▸What is Sibeprenlimab (Voyxact)?
The first APRIL-blocking antibody approved for IgA nephropathy. It has accelerated approval to lower urine protein in adults with primary IgA nephropathy who are at risk of their disease getting worse; it is not yet known whether it slows the loss of kidney function over time. Sibeprenlimab reduces kidney-damaging IgA antibody production by blocking a key immune signal called APRIL.
▸How does Sibeprenlimab work?
Sibeprenlimab blocks a protein called APRIL that tells your immune cells to produce antibodies. In IgA nephropathy, APRIL drives overproduction of defective IgA antibodies that damage kidneys. By blocking this signal at the source, sibeprenlimab reduces the amount of harmful antibodies reaching your kidneys.
▸What are the side effects of Sibeprenlimab?
The most common side effects in the main trial were infections (49% vs 45% on placebo), most often upper respiratory infections such as colds (15% vs 14%), and injection site reactions (24% vs 23%), most often redness. Most were mild or moderate. Because it lowers antibody production, it can raise the risk of infections, so your doctor will check for infections before you start and watch for signs of infection during treatment. Live vaccines are not recommended within 30 days before starting or during treatment.
▸How is Sibeprenlimab taken?
Voyxact is given as a 400 mg injection under the skin once every 4 weeks from a single-dose prefilled syringe, by the patient or a caregiver at home after training. Injections go in the front of the thigh or the belly, and a caregiver can also use the back of the upper arm. If a dose is missed, give it as soon as possible and then go back to every 4 weeks[1].
▸Is Sibeprenlimab FDA approved?
Yes, Sibeprenlimab (Voyxact) is FDA approved (2025) for the treatment of IgA Nephropathy.
▸What is APRIL and why does sibeprenlimab target it?
APRIL (A Proliferation-Inducing Ligand) is a cytokine that signals B cells to produce galactose-deficient IgA1, the harmful antibody that deposits in kidneys and causes damage in IgA nephropathy. Sibeprenlimab neutralizes APRIL to reduce production of these pathogenic antibodies.
▸What clinical trial results have been reported?
In the Phase 3 VISIONARY trial of 510 adults, sibeprenlimab lowered urine protein 51% more than placebo at 9 months, the result behind its November 2025 accelerated approval. Two-year results reported by Otsuka in August 2026 showed kidney function held steady on sibeprenlimab (+0.3 points a year) while it fell 4.2 points a year on placebo. Serious infections occurred in 1.9% on sibeprenlimab and 4.0% on placebo[2].
▸How is sibeprenlimab administered?
Sibeprenlimab (Voyxact) is given as a self-administered subcutaneous injection every 4 weeks. Patients can be trained to inject at home after initial guidance from their care team.
▸How does sibeprenlimab compare to atacicept?
Both target the APRIL pathway, but sibeprenlimab specifically neutralizes APRIL while atacicept blocks both BAFF and APRIL. No trial has compared the 2 directly. Both are FDA-approved for IgA nephropathy on accelerated approval; Voyxact is injected every 4 weeks and Trutakna, approved in July 2026, once a week.
▸How does sibeprenlimab compare to other IgAN treatments?
Sibeprenlimab targets APRIL (upstream immune signal), while iptacopan targets complement factor B, atrasentan targets endothelin, and felzartamab depletes antibody-producing plasma cells. Each addresses a different disease mechanism.
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- U.S. Food and Drug Administration (DailyMed) · March 2026. VOYXACT (sibeprenlimab-szsi) injection, Prescribing Information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c8a93b32-0676-4704-86dc-cb65f425c6e5
- Otsuka Pharmaceutical · 2026-08-04. Otsuka Unveils Unprecedented Phase 3 VISIONARY Two-Year eGFR Results Demonstrating VOYXACT (sibeprenlimab-szsi) Stabilizes Kidney Function Decline to Baseline Physiologic Rate. https://www.otsuka.co.jp/en/company/newsreleases/2026/20260804_2.html