Effects of preemptive interferon-α monotherapy in acute leukemia patients with relapse tendency after allogeneic hematopoietic stem cell transplantation: a case-control study

Interferon- (IFN-) inhibits tumor growth and mimics graft-versus-leukemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In the current case-control study, we compared treatment responses in acute leukemia patients with relapse tendency post-allo-HSCT receiving preemptive IFN- after withdrawal of immunosuppressants (n=31) vs. receiving no IFN- (n=67). In the IFN- group, 25 patients responded to the treatment without progressing to hematological relapse. In the non-IFN- group, only 22 patients responded to the treatment. The response rate differed significantly (80.6 vs. 32.8%, P<0.001). The 2-year cumulative incidence of relapse was 31.6 and 61.2% in the IFN- and the non-IFN groups, respectively (P=0.006). The 2-year leukemia-free survival and overall survival rate was 57.4 vs. 28.4% (P<0.001) and 67.6 vs. 32.9% (P=0.001), respectively. Among the 31 patients in the IFN- group, 18 patients (58.1%) developed graft-versus-host disease (GVHD): 6 acute and 12 limited chronic GVHD. Patients who developed GVHD had higher treatment response rate than patients without GVHD (88.9 vs. 53.8%, P=0.022). In conclusion, preemptive IFN- therapy is a safe and effective treatment to prevent disease progression in high-risk patients with relapse tendency post-allo-HSCT.