CD34 Stem Cell Boost Following Allo-HCT May Improve Outcomes

A systemic review and meta-analysis aimed to assess the outcomes with stem cell boost (SCB) for poor graft function (PGF) in patients with hematologic malignancies undergoing allogeneic hematopoietic stem cell transplantation (allo-HCT). The results were presented during the 2021 ASCO Annual Meeting.

The researchers queried PubMed, Embase, Cochrane, and ClinicalTrials.gov using keywords including “hematological malignancies,” “hematopoietic stem cell transplantation,” “CD34 antigen(s),” and “treatment outcome(s)” from inception through January 2021. A total of 752 articles were screened. The final analysis included eight articles (one prospective, seven retrospective) that reported hematologic complete/overall response rate (CR/ORR), graft-versus-host disease (GVHD), and overall survival (OS) after SCB for PGF after allo-HCT.

The median age of the 217 patients who received SCB for PGF following allo-HCT was 48 years, and the median time since transplant was 133 days. tThe median SCB dose was 3.43 million CD34 cells/kg. CR was 71%, and ORR was 80%. Median follow-up was 41.5 months, at which time the actuarial survival rate was 54%. One-year OS was 80%, and nine-year OS was 40%. The incidences of acute and chronic GVHD were both 17%. One-quarter of deaths were attributed to relapse.

“CD34 SCB improves outcomes after PGF after allo-HCT with acceptable toxicity profile. However, current literature lacks high-quality randomized evidence and there remains an unmet need for prospective studies to address optimal dosing and manipulation of SCB,” the researchers summarized.