Morie Gertz, MD, Hematologist, Chair Emeritus Internal Medicine, Mayo Clinic, discusses post hoc analysis data on the survival benefit of birtamimab in high-risk amyloid light chain (AL) amyloidosis in the phase 3 VITAL study. These data were recently presented at the American Society of Hematology Meeting & Exposition (ASH 2022).
AL amyloidosis is a rare blood disorder associated with the overproduction of amyloid, which leads to the deterioration of vital organs, most notably the heart, kidneys, and liver. The heterogeneity of this disease makes it difficult to diagnose and treat. There is no genetic predisposition for AL amyloidosis nor are there specific environmental factors associated with the disease.
As Dr. Gertz explains, the VITAL study was a phase 3 clinical trial that evaluated the efficacy and safety of birtamimab plus standard of care versus placebo plus standard of care in newly diagnosed, treatment-naïve patients with AL amyloidosis. The study was terminated early based on a futility analysis of the primary endpoint, composite of time to all-cause mortality or cardiac hospitalization. The primary endpoint in the VITAL study population favored birtamimab over placebo, but the difference was not statistically significant at the time of early study termination.
In the post-hoc analysis presented at ASH 2022, the survival benefit of birtamimab was evaluated in patients in the VITAL study deemed high risk (classified as Mayo 2012 Stage IV). Of the 260 patients enrolled in the VITAL study, 77 (29.6%) were characterized as Mayo 2012 Stage IV at baseline (38 had been randomized to birtamimab + standard of care and 39 to placebo + standard of care). Baseline demographic and clinical characteristics were generally balanced between the two treatment groups. After adjustment for key baseline variables, the survival benefit in patients treated with birtamimab was 74% compared to a survival benefit of 49% in patients on placebo at 9 months (p=0.021).
Based on this and other data from the VITAL study, Prothena announced they have advanced birtamimab into the confirmatory phase 3 AFFIRM-AL study. Results are expected in 2024.
To learn more about AL amyloidosis and other rare blood disorders, visit checkrare.com/diseases/hematologic-disorders/.