Low non-relapse mortality and long-term preserved quality of life in older patients undergoing matched related donor allogeneic stem cell transplantation: a prospective multicenter phase II trial

Allogeneic transplantation is a challenge in patients of advanced age because of a high risk of non-relapse mortality and potential long-lasting impairment of health-related quality of life. The development of reduced-intensity conditioning regimens has allowed the use of allogeneic transplantation in this population, but the optimal regimen remains undefined. We conducted a multicenter phase II trial evaluating the safety and efficacy of a reduced-intensity conditioning regimen combining fludarabine, intravenous busulfan, and rabbit antithymocyte globulins in patients older than 55 years of age transplanted from matched-related donor. In addition, health-related quality of life was prospectively measured. Seventy-five patients with a median age of 60 years (range 55-70) were analyzed. Grade III-IV acute and extensive chronic graft-versus-host diseases were found in 3% and 27% of patients, respectively. The day 100 and 1-year non-relapse mortality incidences were 1% and 9%, respectively. The cumulative incidences of relapse, progression-free survival and overall survival at two years were 36%, 51% and 67%, respectively, with a median follow up of 49 months. Global health-related quality of life, physical functioning, emotional functioning, and social functioning were not impaired compared to baseline for more than 75% of the patients (75%, 81.4%, 82.3%, and 75%, respectively). Thirty-four of the 46 (74%) progression-free patients at one year were living without persistent extensive chronic graft-versus-host disease. We conclude that the reduced-intensity conditioning regimen combining fludarabine, intravenous busulfan, and rabbit antithymocyte globulins is well tolerated in patients older than 55 years with low non-relapse mortality and long-term preserved quality of life.