Autologous stem cell transplant (ASCT) in appropriately selected patients with amyloid light-chain (AL) amyloidosis may result in improved long-term clinical outcomes, according to a study published in the American Journal of Hematology. Additionally, transplant-related mortality (TRM) may decline over time.
AL amyloidosis can affect the kidneys, heart, liver, nerves, and skin. Patients with AL amyloidosis have lower incidence of deleterious genetic abnormalities, lower clonal plasma cell burden, and low proliferative rates compared with patients with multiple myeloma, which can allow the possibility of lasting remission with ASCT if short-term mortality can be addressed.
In this 15-year follow-up of 159 patients with AL amyloidosis who underwent ASCT between 1996 and 2003 at the Mayo Clinic in Rochester, Minnesota, researchers assessed survival data and other outcomes. The median follow-up was 17.1 years.
Over two-thirds (69%) of patients had kidney involvement, while 49% had heart involvement and 19% had liver involvement. Involvement of more than 2 organs occurred in 29% of patients. TRM at day 100 was 13.2%.
Overall survival (OS) of 15 years or longer was achieved by 30% of patients. Patients who survived at least 15 years were less likely to have heart involvement (32% vs 56%; P =.005), were younger (53 years vs 56 years; P =.02), and were less likely to have lambda as the involved light chain (62% vs 78%; P =.03).
In patients with heart involvement, median OS was 4.0 years compared with 11.1 years in patients without heart involvement (P =.006). The actuarial 15-year OS was 23% in patients with heart involvement and 43% with no heart involvement.
A total of 81% of patients who received full-dose melphalan conditioning achieved OS of 15 years or longer, compared with 61% of patients who did not receive full-dose melphalan conditioning (P =.01). Similarly, 64% of patients who received melphalan conditioning achieved complete response (CR) at day 100 compared with 24% of patients who did not receive melphalan conditioning (P <.001).
In patients who achieved CR, median OS was 19.3 years; in patients who did not achieve CR, median OS was 5.4 years (P <.001). Over half (52%) of deaths were due to AL amyloidosis and related complications, with 81% of the deaths occurring in years 1 to 5 following ASCT due to the disease and its complications.
Independent factors predictive of OS were achieving CR, heart involvement, and receiving full-dose melphalan.
“Given the excellent long-term outcomes with ASCT in AL amyloidosis, and one-third of patients in our cohort surviving 15 years or longer, ASCT should be considered for early treatment of appropriately selected patients with AL amyloidosis,” the authors concluded. “In the future, we expect the proportion of patients with long-term survival to continue to increase further, given improved TRM and more therapeutic options for relapsed disease.”
1. Sidana S, Sidiqi MH, Dispenzieri A, et al. Fifteen year overall survival rates after autologous stem cell transplantation for AL amyloidosis [published online June 28, 2019]. Am J Hematol. doi:10.1002/ajh.25566