Matched Pair Analysis of Cryopreserved Versus Fresh Allogeneic Peripheral Blood Stem Cell Transplantation

Abstract 4529

Published data about outcome after cryopreserved allogeneic peripheral blood stem cell transplantation are scarce and, so far, have only been compared to historic cohorts of fresh graft recipients. We have performed a matched pair analysis of 66 patients receiving either cryopreserved or fresh grafts from matched related donors at our institution between January 2005 and June 2011 with a median follow-up time of 576 days (range: 18–2080 days).

For matching patients we calculated a propensity score including patient age, sex, diagnosis, performance status, remission status before transplantation (first remission vs. other), conditioning therapy (standard vs. reduced intensity), GvHD prophylaxis (with or without methotrexate) and CD34 cell count in the graft. Consequently, there were no significant differences between both groups for these parameters: median patient and donor age were 53 years (range: 18–68 and 23–76 years, respectively) for 34 male and 32 female patients with a performance status of ECOG 0 (n=60) or ECOG 1 (n=6). Diagnoses were AML (n=47), ALL (8), lymphoma (10) and CMPN (1). 31 patients were in first remission before transplantation. Reduced intensity conditioning therapy (n=52) and GvHD prophylaxis without methotrexate (n=41) were more frequent than standard conditioning (n=14) and prophylaxis with methotrexate (n=25), respectively.

Median cell counts were also almost equal in fresh and cryopreserved grafts for CD34 cells (5.7×10⁶/kg (range: 3.1–11.4×10⁶/kg) vs. 5.1×10⁶/kg (2.6–12.3×10⁶/kg), respectively), total nuclear cells (10.0×10⁸/kg (4.9–21.4×10⁸/kg) vs. 9.6×10⁸/kg (5.0–19.1×10⁸/kg) and CD3 lymphocytes (3.8×10⁸/kg (2.1–6.8×10⁸/kg vs. 3.4×10⁸/kg (0.6–4.5×10⁸/kg)).

All patients engrafted. Median neutrophil engraftment with an ANC >0.5×10⁹/l was reached after 16 days (range: 10–21) vs. 15 days (10–31) (p=.15 by paired t-test) and platelet engraftment >20×10⁹/l (for 3 consecutive days without requiring transfusion) occurred after 13 days (8–33) vs. 14 days (9–45) (p=.27).

Median follow-up time was similar between both groups (566 vs. 586 days, p=.894) and mean overall survival time, as calculated by Kaplan-Meyer analysis, was 1113 days for patients receiving fresh compared to 1258 days for patients receiving cryopreserved grafts (p=.582 by log rank test). Relapse or progression occurred in 13 vs. 14 patients, giving a mean disease/progression-free survival time of 922 vs. 1114 days (p=.467).

In summary, we did not observe any relevant outcome differences between patients receiving fresh or cryopreserved peripheral stem cell grafts of matched related donors. Therefore, the use of cryopreserved grafts can be considered safe and may even allow a more flexible transplant scheduling compared to fresh allografts.