Single‐centre experience with allogeneic bone marrow transplantation for acute lymphoblastic leukaemia in childhood: similar survival after matched‐related and matched‐unrelated donor transplants

Seventy percent of children with acute lymphoblastic leukaemia (ALL) who may benefit from bone marrow transplant (BMT) lack a human leucocyte antigen (HLA)‐matched related donor (MRD). For these children, BMT from a matched unrelated donor (MUD) represents a therapeutic option. We reviewed the course of 62 children with ALL who received fully matched marrow allografts at our institution between 1990 and 1998: 36 with MRDs and 26 with MUDs. Clinical characteristics were similar in the two groups. The interval from attainment of pre‐BMT complete remission to transplant was significantly longer in the MUD group. Conditioning (etoposide/total body irradiation) and graft‐versus‐host disease (GVHD) prophylaxis regimens were the same for all patients, and all received T cell‐replete bone marrow. There was no significant difference in probability of engraftment, or time to engraftment, in the two groups. MUD BMT recipients had a significantly greater incidence of grade II–IV acute GVHD (58% versus 24% in the MRD group; P= 0·02), and demonstrated a trend towards more chronic GVHD (39% versus 15%; P= 0·06). Three years post BMT, the probabilities of transplant‐related mortality were 33 ± 11% and 20 ± 8% in MUD and MRD groups respectively (P = 0·38); the probabilities of relapse were 28 ± 12% and 41 ± 9% respectively (P = 0·19). Lansky or Karnofsky performance scores in event‐free survivors were 90–100 in 87% of the MUD group and 83% of the MRD group. With a median follow up of 38 months (range, 3–97), 3‐year event‐free survival was 49 ± 11% and 47 ± 9% in the MUD and MRD BMT groups respectively (P = 0·71). These results suggest that MUD BMT is a valuable therapy for children with ALL in whom BMT is indicated, and underscore the importance of efforts aimed at expediting unrelated donor searches for patients lacking a MRD.