Adult T-cell leukemia/lymphoma (
ATLL) is a distinct peripheral T-cell
neoplasm that is highly resistant to
chemotherapy. Several groups, including ours, have reported encouraging results of allogeneic
hematopoietic stem cell transplantation (allo-HSCT) for patients with
ATLL. To confirm our previous report and to establish the basis for a phase II clinical study, we analyzed 40 allo-HSCT for acute and
lymphoma types of
ATLL in seven institutions in Japan between 1997 and 2002. All evaluable cases entered complete remission (CR) after allo-HSCT and the median survival time was 9.6 months for all patients. The estimated 3-year overall and relapse-free survival, and disease relapse were 45.3, 33.8 and 39.3%, respectively. Among 10 cases with
ATLL relapse, five cases achieved CR again: three by the reduction or cessation of
immunosuppressive agents, which suggested a graft-versus-
ATLL (GvATLL) effect. However, univariate or multivariate analysis did not show any benefit of
graft-versus-host disease (GVHD) on the prevention of relapse. These results suggested that allo-HSCT was effective for some patients with aggressive
ATLL, and that the GvATLL effect could be achieved even without GVHD. A new phase II trial to test the efficacy of allo-HSCT for
ATLL is warranted.