Allogeneic Stem Cell Transplantation Beneficial for Patients With High-Risk or R/R Chronic Lymphocytic Leukemia

Allogeneic hematopoietic stem cell transplantation (alloHSCT) demonstrated improved outcomes for patients with high-risk or relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL), including those previously treated with pathway inhibitors (PIs), according to study results published in Internal Medicine Journal.

The effect of alloHSCT among patients with CLL, particularly the risk of graft versus host disease (GvHD) and non-relapse mortality (NRM) remain unknown. Researchers conducted retrospective analysis with data from the Australian and New Zealand Transplant and Cellular Therapy Registry for all patients who underwent alloHSCT for CLL between January 2009 and December 2018.

Overall, 140 patients were included, and cancer outcomes were compared between 2 time periods including 2009 to 2013 (n = 94) and 2014 to 2018 (n = 50). Patients in both cohorts were majority male (78% and 70%, respectively) and the median age was 56 (range, 23 to 69) and 54 (range, 25 to 68), respectively.

The 2014 to 2018 cohort demonstrated a shorter median follow up compared with patients in the 2009 to 2013 cohort (5.0 years; interquartile range [IQR], 4.0 to 5.7 vs 7.6 years; IQR, 6.3 to 8.4). While overall survival (OS), progression-free survival (PFS), and relapse rates remained similar between the 2 cohorts, non-relapse mortality (NRM) was significantly higher (42%; 95% CI, 31 to 52) among patients in the 2009 2013 cohort compared to patients in the 2014 to 2018 cohort (23%; 95% CI, 12 to 35; P = 0.02).

Patients in the 2014 to 2018 cohort (33%; 95% confidence interval [CI], 19 to 48) had a lower cumulative incidence of grade II to IV acute GvHD at 100 days than patients in the 2009 to 2013 cohort (52%; 95% CI, 25 to 67, P = .039). However, incidence of cytomegalovirus reactivation was higher in the 2014 to 2018 cohort (48.6%; 95% CI, 31.6 to 63.7) compared with patients in the 2009 to 2013 cohort (40%; 95% CI, 25.6 to 54).

Subgroup analysis among the 2014 to 2018 cohort revealted 22 patients had received prior pathway inhibitor (PI) therapy. The median number of prior lines of therapy for these patients was 3 (range, 2 to 9). Among this subgroup, the 3-year OS was 54% (95% CI, 35 to 82) and PFS were 44% (95% CI, 27 to 71). Additionally, NRM was 25% (95% CI, 8 to 45), and the cumulative incidence of relapse was 32% (95% CI, 14 to 52).

Multivariate analysis demonstrated an associated between transplantation between 2014 to 2018 and improved cancer outcomes including NRM (hazard ratio [HR], 2.01; 95% CI, 1.00 to 4.04; P = .03).

“Allogeneic HSCT remains a viable treatment option for select patients with CLL,” the researchers concluded.

"Transplant registries remain an important source of transplant outcome data. Overall, we have seen an improvement in NRM during the past decade in Australia and New Zealand among patients with CLL undergoing HSCT,” they explained.

“Further studies on outcomes of PI-exposed patients from larger transplant registries or prospective cohort studies may provide further insights into a population that may expand in the coming years as patients experience progressive disease or relapse following novel agents,” they added.

Source:

Barge L, Tran S, Kennedy G, et al. Outcomes of allogeneic haemopoietic transplant for chronic lymphocytic leukaemia in the modern era. Internal Medicine Journal. Published online May 3, 2025. doi:10.1111/imj.70050