Attralus Receives FDA Fast Track Designation for Zamubafusp Alfa in AL Amyloidosis

Attralus has received FDA fast track designation for zamubafusp alfa (AT-02), the company's lead pan-amyloid removal candidate, for the treatment of light chain (AL)-associated amyloidosis, the company announced August 12, 2026.¹ The designation was based on interim phase 2 data from the AT02-003 study, presented at the 67th American Society of Hematology (ASH) Annual Meeting in Orlando, Florida, in December 2025.¹

"We are pleased to have received fast track designation from [FDA] for zamubafusp alfa in AL amyloidosis," said Glen Firestone, president of Attralus, in a company press release.¹ "Current approved therapies for AL target light-chain production, reducing the formation of new amyloid, but there is a significant unmet need for new therapies that can remove existing toxic amyloid fibrils that cause organ damage and mortality."

Why is a new treatment approach needed for AL amyloidosis?

AL amyloidosis is a progressive, multiorgan disease caused by small B-cell clones that produce toxic light chains, which form amyloid deposits most commonly in the heart and kidneys.¹ An estimated 74,000 people are living with AL amyloidosis worldwide, including about 25,000 in the United States, with roughly 4500 new diagnoses annually.¹ The current standard of care, a 4-drug regimen of daratumumab, cyclophosphamide, bortezomib, and dexamethasone, targets light-chain production but does not directly remove existing amyloid deposits, and no approved therapies currently target amyloid removal directly.¹

What clinical data support the designation?

Zamubafusp alfa has been evaluated in a completed phase 1 study and an ongoing phase 2 open-label trial (AT02-003; NCT05951049), both enrolling patients with AL amyloidosis.¹^,² Interim data presented at ASH 2025 showed renal responses in AL amyloidosis patients with kidney involvement who had achieved a hematologic response, supporting zamubafusp alfa's potential to improve organ function beyond hematologic treatment alone.³ All study participants have completed their study visits, with final data anticipated in the second half of 2026.¹

How does zamubafusp alfa work?

Zamubafusp alfa is a humanized immunoglobulin G1 (IgG1) monoclonal antibody genetically fused with Attralus's proprietary pan-amyloid binding peptide, allowing it to bind both lambda and kappa forms of amyloid. Its antibody Fc region is designed to recruit the immune system to clear amyloid deposits bound by the drug, a mechanism the company calls pan-amyloid removal.¹

Fast track designation is intended to facilitate and expedite the development and review of drugs and biologics for serious or life-threatening conditions. Regulatory benefits include more frequent interactions with FDA's review division and eligibility for both rolling review and priority review of a future biologics license application.¹

What's next for zamubafusp alfa?

Zamubafusp alfa has also received orphan drug designations from FDA for AL amyloidosis and transthyretin-associated (ATTR) amyloidosis as well as positive opinions for orphan designation from the European Medicines Agency’s Committee for Orphan Medicinal Products (COMP) for both indications.¹ Attralus said the fast track designation will let the company work closely with FDA on the most efficient clinical development pathway for AT-02.¹

What are the limitations?

Fast track designation facilitates FDA interactions but does not guarantee eventual approval. The data supporting this designation are interim results, and full phase 2 results have not yet been reported or peer-reviewed beyond the ASH conference abstract.

References

1. Attralus. Attralus has been granted US FDA Fast Track designation for zamubafusp alfa (AT-02) for the treatment of AL amyloidosis. Press release. Published August 12, 2026. Accessed August 12, 2026. https://attralus.com/press-releases/attralus-has-been-granted-u-s-fda-fast-track-designation-for-zamubafusp-alfa-at-02-for-the-treatment-of-al-amyloidosis
2. ClinicalTrials.gov. A study of AT-02 in subjects with systemic amyloidosis (AT02-003). NCT05951049. Updated May 6, 2026. Accessed August 12, 2026. https://clinicaltrials.gov/study/NCT05951049
3. Bell G, Sherman C, Meldorf M, et al. Renal responses in a phase 1/2 study of AT-02, a novel pan-amyloid depleter Ig fusion protein for the treatment of patients with AL amyloidosis. Blood 2025;146 (Supplement 1):693. doi:10.1182/blood-2025-693