Interferon alpha for chronic myeloid leukemia relapsing after allogeneic bone marrow transplantation

Interferon alpha (IFN alpha) induces cytogenetic responses in patients with chronic myeloid leukemia (CML) who relapse after allogeneic bone marrow tr ansplantation (BMT). The purpose of this study was to analyze the therapeut ic role of IFN alpha in this setting. The experience of a single institutio n and the published results on this topic were evaluated, We have included patients who received IFN alpha as a single agent, excluding those patients who received previous or simultaneous donor leukocyte infusions, The outco mes of 11 patients treated in our center and those of 108 previously report ed patients have been analyzed. Five out of 11 patients treated in our inst itution obtained a complete cytogenetic response (CGR). Two patients contin ue in complete cytogenetic response 3.5 and 8.2 years later, and the qualit ative RT-PCR is negative for bcr-abl RNA. The CGR has been transient in one patient, and follow-up is short in the other two. Secondary effects have b een acceptable, with myelosuppression as the main toxic effect, Graft-versu s-host disease did not occur. The literature review identified 108 patients treated with IFN alpha as sole therapy for relapsed CML, Cytogenetic respo nse and CGR seem to be better in patients with cytogenetic relapse, as comp ared to patients with hematologic relapse (61% vs 45% and 45% vs 28%, respe ctively). Several patients remained in CGR for more than 5 years. This over view also suggests that CGR is more frequent when IFN alpha is used in pati ents relapsing after non T-depleted BMT, IFN alpha induces complete cytogen etic response in nearly half of the patients with CML who relapse after all ogeneic BMT, with acceptable toxicity, We believe that these results using IFN alpha as a front-line therapy for CML relapsing after BMT warrant a ran domized comparison with donor lymphocyte infusions.