Outcomes and prognostic factors of adults with acute lymphoblastic leukemia who relapse after allogeneic hematopoietic cell transplantation. An analysis on behalf of the Acute Leukemia Working Party of EBMT.

To describe outcomes, treatment and prognostic factors that influence survival of adult patients with acute lymphoblastic leukemia (ALL), who relapsed after allogeneic hematopoietic cell transplantation (HCT), we retrospectively analyzed 465 ALL adult patients from European Group for Blood and Marrow Transplantation (EBMT) centers who relapsed after a first HCT performed in complete remission (CR1 65%, CR2/3 35%). Salvage treatments were: supportive care (13%), cytoreductive therapy (43%), donor lymphocyte infusion without or with prior chemotherapy (23%) and second HCT (20%). Median time from HCT to relapse was 6.9 months, median follow-up was 46 months and median survival after relapse was 5.5 months. Estimated 1-, 2- and 5-year post-relapse survival was 30 ± 2%, 16 ± 2% and 8 ± 1%, respectively. In a multivariate analysis, adverse factors for survival were: late CR (CR2/3) at transplant (P<0.012), early relapse after transplant (<6.9 months, P <0.0001) and peripheral blast percent at relapse (P <0.0001). On the basis of multivariate model for survival, three groups of patients were identified with estimated 2 year survival of 6 ± 2, 17 ± 3 and 30 ± 7%. Outcome of ALL patients relapsing after HCT is dismal and there is a need for new therapies. Our study provides the standard expectations in ALL relapse and may help in the decision of post-relapse therapy.