Attralus' Zamubafusp Alfa Receives FDA Orphan Drug Designation for AL Amyloidosis
Key Insights
The U.S. FDA granted orphan drug designation to Attralus' zamubafusp alfa (search) (AT-02) for the treatment of light chain (AL) amyloidosis, a rare and often fatal condition.
Zamubafusp alfa (search) is a first-in-class pan-amyloid removal therapeutic designed to directly bind to and clear existing toxic amyloid deposits from organs, addressing a critical unmet need.
Current approved AL amyloidosis (search) therapies only target light-chain production to reduce new amyloid formation, leaving no approved options for removing pre-existing amyloid fibrils.
NAPLES, Fla., June 4, 2026 — Attralus, Inc., a clinical-stage biopharmaceutical company, announced that the U.S. Food and Drug Administration (FDA) has granted orphan drug designation to zamubafusp alfa (search) (AT-02) for the treatment of light chain (AL) amyloidosis, a rare, progressive, debilitating, and often fatal condition. The designation marks a significant regulatory milestone for the company's lead pan-amyloid removal (PAR) therapeutic candidate.
Zamubafusp alfa (search) has been evaluated in a completed Phase 1 study and is currently being studied in an ongoing Phase 2 open-label trial, both of which enrolled patients with AL amyloidosis (search).
"We are pleased to have received orphan drug designation from the U.S. FDA for zamubafusp alfa (search) in AL amyloidosis (search)," said Gregory Bell, M.D., Chief Medical Officer at Attralus. "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."
Orphan Drug Designation Benefits
The FDA's Orphan Drug Designation applies to drugs and biologics intended for the safe and effective treatment, diagnosis, or prevention of rare diseases or conditions affecting fewer than 200,000 people in the United States. The designation provides Attralus with several development incentives, including tax credits for clinical costs, exemptions from certain FDA fees, and the potential for seven years of marketing exclusivity upon approval.
Mechanism of Action and Clinical Development
Zamubafusp alfa (search) is a humanized IgG1 monoclonal antibody genetically fused with the company's proprietary pan-amyloid binding peptide, enabling binding to multiple types of amyloid deposits. The Fc region of the antibody stimulates the immune system to remove amyloid deposits bound by zamubafusp alfa. Preclinical data has demonstrated the ability of zamubafusp alfa to bind to multiple amyloid types in major organs, induce macrophage-mediated phagocytosis, and remove amyloid.
The PAR therapeutic approach represents a departure from existing treatment paradigms. While the current standard of care — the combination of daratumumab, cyclophosphamide, bortezomib, and dexamethasone (dara-CyBorD) — targets light-chain production to reduce new amyloid formation, zamubafusp alfa (search) is designed to directly bind to and remove toxic amyloid already deposited in organs and tissues.
Disease Burden and Unmet Need
AL amyloidosis (search) is a progressive, systemic, multiorgan orphan disease with significant morbidity, most commonly affecting the heart and kidneys. Worldwide, an estimated 74,000 patients are living with AL amyloidosis. In the United States, prevalence is approximately 25,000, with about 4,500 new patients diagnosed annually. The disease is caused by small B-cell clones that produce a toxic light chain forming amyloid deposits in tissues.
Achieving a profound hematologic response is the early goal of treatment with dara-CyBorD, yet there are no approved therapies that directly target amyloid removal. Amyloid-depleting therapies are needed to improve organ function, and there is a significant unmet need for patients in hematologic remission who have persistent organ dysfunction, whether cardiac or renal.
Global Regulatory Progress
Beyond the newly granted FDA orphan drug designation for AL amyloidosis (search), zamubafusp alfa (search) has also received FDA orphan drug designation for the treatment of transthyretin-associated amyloidosis (search) (ATTR). Additionally, the European Medicines Agency's Committee for Orphan Medicinal Products (COMP) adopted positive opinions for orphan medicinal product designations for zamubafusp alfa for both ATTR and AL amyloidosis, underscoring the global recognition of the therapeutic's potential across multiple forms of systemic amyloidosis.
Attralus, founded by scientific experts in the field of amyloidosis and headquartered in Naples, Florida, is focused on creating transformative medicines to improve the lives of patients with systemic amyloidosis. The company's PAR therapeutics are designed to treat and potentially reverse disease in patients with all types and stages of systemic amyloidosis by targeting the disease-causing pathology directly.