DLI after haploidentical BMT with post-transplant CY.

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• Relapse after unmanipulated haploidentical stem cell transplantation with post-transplant cyclophosphamide (PT-CY) remains a clinical challenge.
• Donor lymphocyte infusions (DLI) are a potential strategy to overcome relapse by leveraging graft-versus-leukemia effects.
• Optimizing DLI dosing and administration in the haploidentical setting requires further investigation.

Purpose of the Study:

• To evaluate the safety and efficacy of escalating doses of DLI in patients relapsing after haploidentical BM transplant and PT-CY.
• To assess the impact of DLI on response rates and survival across different hematologic malignancies.
• To determine the incidence of graft-versus-host disease (GVHD) associated with DLI administration.

Main Methods:

• Forty-two patients with relapsed leukemias or Hodgkin's disease post-haploidentical BM transplant and PT-CY received 108 DLI.
• DLI were administered at escalating doses (1 x 10^3 to 1 x 10^7 CD3+ cells/kg) without GVHD prophylaxis.
• Patients received DLI alone or in combination with chemotherapy or azacytidine based on disease status and relapse type.

Main Results:

• Escalating DLI doses were safely administered, with a low incidence of acute GVHD (10-15%) across treatment groups.
• Overall response rates varied: 45% for molecular relapse leukemias, 33% for hematologic relapse leukemias, and 70% for Hodgkin's disease.
• Two-year actuarial survival rates were 43% (molecular relapse), 19% (hematologic relapse), and 80% (Hodgkin's disease).

Conclusions:

• Escalating doses of DLI can be safely administered in the haploidentical setting with PT-CY, demonstrating a manageable GVHD risk.
• Treatment response and survival outcomes following DLI are significantly influenced by the underlying hematologic malignancy and relapse status.
• DLI represents a viable therapeutic option for relapsed hematologic malignancies post-haploidentical transplantation, with tailored approaches needed for optimal results.