Background: Recent studies have shown dismal outcomes when chronic lymphocytic leukemia progresses to Richter syndrome after patients receive ibrutinib, with a median overall survival ranging from 2.6 to 3.5 months. Published data on efficacy of allogeneic hematopoietic cell transplantation in Richter syndrome are limited to single-center case series and registry data.
Patients and methods: We evaluated the efficacy of allogeneic transplantation in 10 patients, median age of 63 (range, 50-74) years, allografted at a median of 5 (range, 4-25) months from diagnosis of Richter syndrome. All showed an objective response to therapy before transplantation (first complete remission = 7 [70%], first partial response = 2 [20%], second partial response = 1 [10%]). Most received a myeloablative conditioning regimen (n = 7, 70%). Filgrastim-mobilized peripheral blood stem cells was the preferred cell source (n = 10, 100%).
Results: Median follow-up of surviving patients was 46 (range, 15-82) months. The 4-year overall survival was 50% (95% confidence interval [CI], 19%-81%). Nonrelapse mortality at 1 year and 4 years post-transplantation were 40% (95% CI, 19%-85%) for both time points. The 4-year incidence of relapse/progression was 10% (95% CI, 2%-64%).
Conclusion: Allogeneic hematopoietic cell transplantation is an effective treatment for patients with Richter syndrome who show an objective response before allografting. Patients must be referred to transplant centers as soon as the diagnosis is confirmed to evaluate candidacy for the procedure and identify a suitable donor in a timely manner.
Keywords: Chronic lymphocytic leukemia transformation; Nonrelapse mortality; Objective response; Overall survival; Relapse/progression.
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