Atacicept (Trutakna): The First Dual BAFF/APRIL Inhibitor Approved for IgA Nephropathy (September 29, 2026)
Table of Contents
- What atacicept is, in one line
- The problem it targets: BAFF, APRIL and Gd-IgA1
- What ORIGIN 3 showed
- The FDA approval - and the accelerated-approval asterisk
- How it compares: atacicept vs sibeprenlimab vs povetacicept vs the rest
- A long, winding road: lupus, the MS surprise, and kidney disease
- What we still don't know - and the bottom line
What atacicept is, in one line
Atacicept (now branded Trutakna) is a lab-made 'decoy' protein for IgA nephropathy, a chronic kidney disease. It is a TACI-Fc fusion protein - the ligand-binding part of the TACI receptor stitched to an antibody Fc tail - and its job is to soak up two immune-signaling molecules, BAFF and APRIL, that keep antibody-producing B cells alive. By capturing both at once it is the first and only 'dual BAFF/APRIL inhibitor' the FDA has approved for the disease. Patients give it to themselves as a 150 mg shot under the skin once a week.
The problem it targets: BAFF, APRIL and Gd-IgA1
IgA nephropathy is usually explained with a 'four-hit' model. First, certain B cells and plasma cells overproduce a faulty antibody called galactose-deficient IgA1 (Gd-IgA1). Second, the immune system makes autoantibodies against that faulty IgA1. Third, the two stick together into immune complexes. Fourth, those complexes lodge in the kidney's filtering units (the mesangium), where they spark inflammation, leak protein into the urine (proteinuria) and slowly scar the kidney - a path that leads a large share of patients toward kidney failure over their lifetime. BAFF (B-cell activating factor) and APRIL (a proliferation-inducing ligand) are the survival signals that keep the Gd-IgA1 'factory' running. Atacicept blocks both, aiming to turn the disease down at its source rather than managing damage after the fact.
What ORIGIN 3 showed
The approval rests on ORIGIN 3 (NCT04716231), a global Phase 3 trial that randomized 431 adults with IgA nephropathy to atacicept or placebo on top of standard care. At the week-36 primary analysis, atacicept reduced urine protein (measured as the urine protein-to-creatinine ratio, UPCR) by 46% from baseline and by 42% compared with placebo, a highly statistically significant result (p<0.0001). It also cut the pathogenic Gd-IgA1 antibody by about 68% and resolved hematuria - microscopic blood in the urine, a marker of active kidney inflammation - in roughly 81% of participants who had it at the start. Safety was reassuring in the trial: serious adverse events occurred in just 0.5% of atacicept patients versus 5% on placebo, with no deaths in either group. The findings were presented as a late-breaker at ASN Kidney Week 2025 and published in the New England Journal of Medicine.
The FDA approval - and the accelerated-approval asterisk
On July 7, 2026 the FDA granted atacicept accelerated approval under the brand name Trutakna, to reduce proteinuria in adults with primary IgA nephropathy who are at risk of disease progression. It reached that point with Breakthrough Therapy Designation and Priority Review behind it. The word 'accelerated' matters. The approval is based on proteinuria - a surrogate marker that is reasonably likely to predict benefit - rather than on years of hard data showing preserved kidney function. To convert this into full approval and confirm real long-term benefit, ORIGIN 3 continues, with a two-year kidney-function (eGFR) readout as the confirmatory endpoint. Vera Therapeutics aligned with the FDA on an earlier eGFR analysis expected in Q3 2026 and has signaled a supplemental filing in Q4 2026, with a potential full-approval decision in 2027. Until that confirmatory data lands, the honest framing is: atacicept clearly and durably lowers protein in the urine; whether that keeps kidneys working longer is the question still being answered.
How it compares: atacicept vs sibeprenlimab vs povetacicept vs the rest
IgA nephropathy went from having almost no targeted therapies to a genuinely crowded field, and the new agents differ in what they hit and how often you dose them. Atacicept blocks BOTH BAFF and APRIL as a wild-type TACI-Fc decoy, dosed weekly. Sibeprenlimab (VOYXACT, from Otsuka) is a monoclonal antibody that blocks APRIL only, dosed monthly. Povetacicept is another dual BAFF/APRIL blocker, but built from an ENGINEERED TACI variant designed for tighter binding, dosed roughly monthly. Felzartamab takes a different route entirely - it depletes the antibody-producing plasma cells themselves via CD38. And outside the B-cell axis, iptacopan (Fabhalta) blocks complement factor B, while targeted-release budesonide (Tarpeyo) acts on gut-associated immune tissue. The open scientific question the field is running in real time: does hitting both BAFF and APRIL (atacicept, povetacicept) beat hitting APRIL alone (sibeprenlimab), and is more suppression always better, or does it cost more in infection risk?
A long, winding road: lupus, the MS surprise, and kidney disease
Atacicept is not a new molecule - it is a new indication for an old one. It originated at ZymoGenetics, was developed by Merck KGaA (Merck Serono), and was out-licensed to Vera Therapeutics in 2020. Its earlier life is a cautionary tale. In systemic lupus (the APRIL-SLE and ADDRESS II programs) a high-dose arm was halted after serious and fatal infections, even as hints of fewer severe flares appeared. More striking still, in the Phase 2 ATAMS trial in multiple sclerosis, atacicept UNEXPECTEDLY INCREASED relapses compared with placebo and the study was stopped early. That same BAFF/APRIL biology that calms IgA nephropathy appears to have inflamed MS - a reminder that immune pathways are not simply 'good' or 'bad' but depend entirely on the disease. Atacicept's success in the kidney is, in part, the story of a drug finally matched to the right problem.
What we still don't know - and the bottom line
The biggest unknown is the one accelerated approval was designed around: whether atacicept's large drop in proteinuria translates into slower loss of kidney function and fewer people reaching dialysis or transplant over years. The confirmatory eGFR data from ORIGIN 3 is meant to answer that. Beyond efficacy, the mechanism carries a built-in trade-off - blocking BAFF and APRIL lowers protective antibodies (IgG, IgA, IgM) and can raise infection risk, so vaccination status and infection monitoring matter, and live vaccines are generally avoided. None of this is a do-it-yourself therapy: atacicept is a prescription biologic managed by a nephrologist, and any 'atacicept' or 'Trutakna' offered by an online vendor is unverified and unsafe. The bottom line: atacicept is a genuine milestone - the first dual BAFF/APRIL inhibitor approved for IgA nephropathy, with strong, durable proteinuria and Gd-IgA1 data - now waiting on the kidney-survival evidence that will tell us how big a milestone it really is.
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Citations
- [1] Atacicept in Patients with IgA Nephropathy (ORIGIN 3) - New England Journal of Medicine (2025) Source
- [2] Vera Therapeutics Announces Positive ORIGIN Phase 3 Data for Atacicept in IgA Nephropathy (ASN Kidney Week 2025 / NEJM) Source
- [3] FDA Approves Atacicept (Trutakna) for IgA Nephropathy - HCPLive (2026) Source
- [4] The FDA Grants Accelerated Approval to Atacicept for Adults with IgAN - NephCure (2026) Source
- [5] Vera Therapeutics Announces Alignment with U.S. FDA on Earlier ORIGIN Phase 3 Analysis to Support Potential Full Approval Source
- [6] A Study of Atacicept in Subjects With IgA Nephropathy (ORIGIN) - ClinicalTrials.gov NCT04716231 Source
- [7] Atacicept in multiple sclerosis (ATAMS): a randomised, placebo-controlled, double-blind, phase 2 trial - The Lancet Neurology (2014) Source
- [8] Merck (KGaA) Announces Out-Licensing Agreement for Investigational Atacicept with Vera Therapeutics (2020) Source
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Povetacicept (ALPN-303) is an investigational once-monthly fusion protein that blocks both BAFF and APRIL, the cytokines that keep antibody-producing B cells alive. Built from an engineered TACI decoy fused to an antibody Fc, it targets the B-cell driver of IgA nephropathy. A positive Phase 3 RAINIER interim analysis and an FDA accelerated-approval filing (PDUFA November 30, 2026) have made it one of the most closely watched biologics in nephrology.
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