Anselamimab (formerly CAEL-101) is an investigational anti-fibril monoclonal antibody for light-chain (AL) amyloidosis that was acquired by AstraZeneca through its Alexion rare disease division (Alexion Pharmaceuticals) following the acquisition of Caelum Biosciences in 2021. Designed to directly target and clear amyloid fibrils, anselamimab represents a differentiated therapeutic approach that complements existing plasma cell–directed therapies by addressing the underlying organ-damaging amyloid deposits.

In the Phase III CARES trial, anselamimab in combination with standard-of-care therapy did not meet its primary endpoint in the overall AL amyloidosis population. However, the study identified a clinically meaningful benefit in the prespecified κ light-chain amyloidosis subgroup, where the therapy reduced ACM by 62% and CVH by 71% versus placebo. These findings position anselamimab as a potential first-in-class anti-fibril therapy for κ AL amyloidosis and support a more biomarker-driven approach to treatment in this rare disease.

Key Efficacy Highlights:

• In patients with λ iFLC, anselamimab reduced CVH risk by 10%, with no improvement in all-cause mortality

Key Safety Highlights

• Safety outcomes were comparable between the anselamimab and placebo arms

• The safety profile of anselamimab in the κ subgroup was consistent with that observed in the overall study population.

KOL insights

“The CARES findings reinforce the importance of subtype-specific treatment approaches in AL amyloidosis, with anselamimab demonstrating meaningful survival and cardiovascular benefits in κ AL patients and the potential to become the first disease-modifying anti-fibril therapy for this underserved population." – Expert Opinion

“Anselamimab has the potential to provide a novel, clinically meaningful therapeutic option for patients with κ AL amyloidosis, a subgroup that can be readily identified using simple, routinely available diagnostic tools.”– Expert Opinion

Conclusion-

Light-chain (AL) amyloidosis is a rare, life-threatening plasma cell disorder, with ~43–47% of patients in the US and Germany presenting at advanced Stage IIIa/IIIb, reflecting delayed diagnosis and a high burden of severe cardiac involvement. While daratumumab (DARZALEX)-based regimens have reshaped frontline care by significantly improving hematologic responses and survival, outcomes remain limited by persistent cardiac and renal dysfunction, as current therapies primarily target clonal plasma cells without effectively reversing established organ damage. This has driven a clear shift in the treatment paradigm toward targeted monoclonal antibodies, bispecifics, and cellular immunotherapies designed to achieve both hematologic control and organ recovery. Within this evolving landscape, anselamimab, an anti-amyloid fibril antibody, represents a novel disease-modifying approach aimed at directly clearing amyloid deposits. In the Phase III study, anselamimab demonstrated an improvement in all-cause mortality, highlighting its potential to translate amyloid removal into meaningful survival benefit and positioning it to potentially reshape the future treatment paradigm in AL amyloidosis.