Transfusion Outcomes Following Allogeneic Hematopoietic Stem Cell Transplantation in Patients With Transfusion-Dependent Beta-Thalassemia: A Systematic Literature Review

OBJECTIVES: To synthesize evidence from published literature on transfusion independence in patients with transfusion-dependent beta-thalassemia (TDT) following allogeneic hematopoietic stem cell transplant (HSCT).

METHODS: A systematic literature review was conducted in MEDLINE and Embase to identify English-language publications from interventional and non-interventional studies (up to May 2023) that assessed transfusion outcomes in patients with TDT who underwent allogeneic HSCT. Studies that only reported HSCT-related outcomes were excluded. Proportion of patients with transfusion outcomes were aggregated and descriptively reported; data on study-reported transfusion independence (TI) and transfusion dependence (TD) was harmonized as proportion of patients achieving TI after HSCT.

RESULTS: Forty-five studies including 1,749 patients met study inclusion criteria. Most studies included pediatric patients (88.9%), employed a myeloablative conditioning regimen (66.7%), and included patients treated with matched-sibling donor (55.6%). Follow-up period for outcome assessment after HSCT varied with a median of 2 years.

Studies defined TI as absence of regular transfusions after HSCT and TD as dependence on regular transfusions after HSCT. Overall, 1,537 (87.9%) patients achieved engraftment and were TI during follow-up after HSCT (within-study range: 50%-100%). Proportion of patients who achieved TI was similar in subsets of studies with at least 6-month or 1-year follow-up after HSCT to account for the period for planned post-HSCT transfusion support.

CONCLUSIONS: Based on this systematic literature review, a portion of patients with TDT continue to require regular transfusions after allogeneic HSCT. Given these limitations with allogeneic HSCT, additional curative treatment approaches are needed for patients with TDT.