AstraZeneca’s anselamimab has failed to show any benefit in patients with light chain (AL) amyloidosis in two Phase III trials.
A light chain depleter antibody, anselamimab was being investigated in the Cardiac Amyloid Reaching for Extended Survival (CARES) programme in patients with Mayo stages IIIa (NCT04512235) and Mayo stages IIIb (NCT04504825) AL amyloidosis.
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AstraZeneca’s AL amyloidosis drug did not achieve statistical significance for the primary endpoint – defined as a combination of time to all-cause mortality (ACM) and frequency of cardiovascular hospitalisations (CVH), in either study.
AstraZeneca’s rare disease unit, Alexion, which has been developing the drug, said the therapy demonstrated a clinically meaningful improvement in the primary endpoint in a prespecified subgroup of patients, compared to placebo. Alexion did not provide any additional details about this group.
AstraZeneca acquired Alexion in a deal worth up to £39bn in 2020, which included anselamimab among other rare disease drugs. The company is now operated as a subsidiary of AstraZeneca.
Alexion CEO Marc Dunoyer said: “Alexion is pioneering a novel mechanism of action to address organ damage from existing amyloid deposits in patients with AL amyloidosis, a devastating disease often diagnosed in advanced stages with poor prognosis.
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By GlobalData“Anselamimab is the first and only investigational fibril depleter to show clinical benefit in AL amyloidosis, and these results underscore its potential to address a critical treatment gap in a prespecified subgroup of patients.”
The drug remained well tolerated in the study, with adverse events (AEs) balanced between the treatment and placebo arms.
Alexion is continuing to evaluate the data and plans to speak with global health authorities and present data at a forthcoming medical meeting.
The Phase III programme recruited a total of 406 patients, 281 with Mayo stage IIIa AL amyloidosis and 125 with Mayo stage IIIb AL amyloidosis.
AL amyloidosis is a rare, systemic and progressive disorder caused by defective plasma cells in the bone marrow. In AL amyloidosis, abnormal light chain proteins produced by these plasma cells misfold, aggregate and form amyloid fibrils that deposit in tissues and organs. Left untreated, the accumulation of these toxic amyloid deposits, particularly in the heart and kidneys, can cause progressive organ damage and dysfunction and may lead to premature death, most commonly due to cardiac failure.
This is a second hit to the monoclonal antibody (mAb) approach in AL amyloidosis after Prothena’s mAb, birtamimab, failed to meet the primary endpoint in a Phase III trial, with the company announcing it was discontinuing development of the drug in May 2025.
The only drug approved by the US Food and Drug Administration (FDA) for AL amyloidosis is Darzalex Faspro (daratumumab and hyaluronidase-fihj) in combination with cyclophosphamide, bortezomib, and dexamethasone.
There are some therapies in the pipeline, including Immix Biopharma’s NXC-201, which showed promise in relapsed/refractory AL amyloidosis in a Phase Ib/IIa study. The therapy has also received orphan drug designation by the agency.
GlobalData predicts that, if approved, anselamimab will make $570m in global sales in 2031.
In the same year, daratumumab hyaluronidase is forecast to make $15bn in sales; however, the drug is already approved and being investigated in several indications beyond AL amyloidosis, including some oncology indications.
GlobalData is the parent company of Clinical Trials Arena.
