Abstract
BACKGROUND: Allogeneic haemopoietic stem cell transplantation (HSCT) is an effective therapy with curative potential for patients with high-risk or relapsed/refractory chronic lymphocytic leukaemia (CLL). There are limited data on the use and outcomes of HSCT in the modern era of CLL treatment. AIMS: The aim of this study was to examine the use of HSCT performed for CLL in Australia and New Zealand, including patients exposed to pathway inhibitors (PIs) prior to transplant. METHODS: Data were collected through the Australian and New Zealand Transplant and Cellular Therapy Registry for all patients who underwent HSCT for CLL between January 2009 and December 2018. Transplant outcomes were compared between two 5-year time periods: 2009-2013 and 2014-2018. RESULTS: Ninety-four patients underwent HSCT during 2009-2013 and 50 during 2014-2018. There was a significant reduction in non-relapse mortality (NRM) from 42% (95% confidence interval (CI): 31-52) to 23% (95% CI: 12-35, P = 0.02) between the periods; however, overall survival (OS), progression-free survival (PFS) and relapse were unchanged. Within the 2014-2018 cohort, 22 patients were PI exposed prior to transplant. At 3 years, these patients demonstrated a median OS of 54% (95% CI: 35-82), PFS of 44% (95% CI: 27-71), NRM of 25% (95% CI: 8-45) and cumulative incidence of relapse of 32% (95% CI: 14-52). In multivariate analysis, only disease in complete remission at the time of HSCT was associated with improved OS (hazard ratio: 2.54, 95% CI: 1.04-6.18). CONCLUSION: Allogeneic HSCT remains a viable treatment option for select patients with CLL.