The following is a summary of “Birtamimab plus standard of care in light chain amyloidosis: the phase 3 randomized placebo-controlled VITAL trial,” published in the June 2023 issue of Hematology by Gertz et al.
Amyloid light chain (AL) amyloidosis is a rare, deadly disease caused by misfolded immunoglobulin light chains (LCs) buildup.
Researchers performed a retrospective study to utilize Birtamimab, a humanized monoclonal antibody, to neutralize toxic LC aggregates and remove insoluble organ-deposited amyloid. Phase 3 VITAL trial examined the effectiveness and safety of Birtamimab plus standard of care (SOC) in 260 recently diagnosed, treatment-naïve AL amyloidosis patients in a randomized, double-blind, placebo-controlled setting. Patients were given Birtamimab (24 mg/kg) or a placebo every 28 days, along with the standard of care (SOC). The primary endpoint was all-cause mortality (ACM) or cardiac hospitalization (≥91 days after the first infusion). The trial was terminated early as there was no significant difference in the primary endpoint (hazard ratio [HR] = 0.826; 95% CI 0.574-1.189; log-rank P= .303).
A post hoc analysis of patients with Mayo Stage IV AL amyloidosis, who were at the highest risk of early mortality, showed that Birtamimab was associated with a significant improvement in time to death at 9 months (HR = 0.413; 95% CI: 0.191-0.895; log-rank P = .021), 74% of patients with Mayo Stage IV AL amyloidosis who were treated with Birtamimab were still alive at 9 months, compared to 49% of patients who received placebo.
The study found that the rates of side effects between Birtamimab and placebo were similar. A confirmatory trial is currently enrolling patients with Mayo Stage IV AL amyloidosis.