Donor-specific transplant outcomes from BMT CTN 1702: a multicenter prospective biologic assignment trial

Area of Science:

• Hematology
• Transplantation immunology
• Clinical research

Background:

• Alloreactivity control is crucial for successful hematopoietic stem cell transplantation (HCT).
• Prospective comparisons between HLA-matched unrelated donors (MUD) and alternative donor sources are limited.
• Donor selection significantly impacts transplant outcomes.

Purpose of the Study:

• To compare HCT outcomes using MUD versus haploidentical (HAPLO), mismatched unrelated (MMUD), and umbilical cord blood (UCB) donors.
• To evaluate the impact of donor type on survival, relapse, treatment-related mortality (TRM), and graft-versus-host disease (GVHD).
• To inform donor selection strategies for patients lacking matched sibling donors.

Main Methods:

• BMT CTN 1702 trial prospectively assigned patients without matched sibling donors to MUD or center's preferred alternative donor (HAPLO, MMUD, UCB).
• Outcomes were compared between donor groups using multivariate analysis, adjusting for covariates.
• Post-transplant cyclophosphamide (PTCy) use was recorded and analyzed.

Main Results:

• Survival was significantly lower for UCB recipients compared to MUD, but not different for HAPLO or MMUD recipients.
• UCB recipients had inferior TRM and disease-free survival (DFS) compared to MUD.
• In PTCy patients, HAPLO and MMUD were associated with increased acute and chronic GVHD compared to MUD.

Conclusions:

• Haploidentical and mismatched unrelated donors may be effective alternatives to MUD, expediting transplantation when MUD are unlikely.
• Umbilical cord blood transplantation is associated with poorer outcomes compared to MUD, HAPLO, and MMUD.
• Donor selection strategies should consider donor type, patient factors, and GVHD prophylaxis.