Predictive factors for successful imatinib cessation in chronic myeloid leukemia patients treated with imatinib.

Although recent studies have suggested that cessation of imatinib (IM) in chronic myeloid leukemia patients can be associated with sustained response, further validation is needed to explore predictive factors. In a prospective, multicenter study, chronic phase patients were eligible for cessation of IM therapy after more than 3 years if they had no detectable BCR-ABL1 transcript for at least 2 years. A total of 48 patients with a median age of 47 years (19-74 years) were enrolled. Twenty patients received IM for post-transplant relapse. After a median follow-up of 15.8 months (1.4-28.2 months) after IM discontinuation, nine of the non-transplant group lost undetectable molecular residual disease (UMRD) and major molecular response (MMR), whereas none of the 20 patients in the transplant group experienced UMRD loss. Probabilities for sustained MMR and UMRD were 64.4% and 66.3% in the non-transplant group, respectively. Of nine patients re-treated with IM, eight patients re-achieved MMR at a median of 1.7 months (0.9-2.8 months). Seven of these patients re-achieved UMRD at a median of 5.6 months (2.8-12.1 months). Previous transplantation, IM duration, and UMRD duration were significantly associated with sustained molecular responses. Our data strongly suggest that immunological control contributes to sustained suppression of residual leukemia cell expansion and that IM can be safely discontinued in patients with post-transplant relapse.

Prognostic factors for outcomes of allogeneic stem cell transplantation in chronic phase chronic myeloid leukemia in the era of tyrosine kinase inhibitors.

The aim of this study was to estimate the prognostic factors for the outcomes of chronic myeloid leukemia (CML) patients receiving allogeneic stem cell transplantation (SCT) in chronic phase (CP) in the era of tyrosine kinase inhibitors (TKIs). Ninety-seven patients who underwent allogeneic SCT in CP were analyzed. Forty-seven were TKI-naïve at the time of transplant, and 50 received TKI(s) treatment before transplantation. After a median follow-up of 115.8 months, the 4-year overall survival and event-free survival were 80.4 and 58.8%, respectively. Multivariate analysis showed that there were no differences in survival outcomes based on prior TKI therapy. Older age was a prognostic factor for higher treatment-related mortality (TRM), and the type of graft source and younger age were associated with relapse, but prior TKI therapy and disease status at the time of transplant were not associated with either TRM or relapse. Additionally, a major molecular response at 1 month and an MR(4.5) at 3 months were important predictors of favorable long-term outcomes. This study demonstrates the prognostic factors for the outcomes of allogeneic SCT in CP CML and shows that survival outcomes were not affected by the administration of long-term multi-TKI treatment prior to transplantation.

The long-term clinical implications of clonal chromosomal abnormalities in newly diagnosed chronic phase chronic myeloid leukemia patients treated with imatinib mesylate.

The aim of this study was to evaluate the long-term clinical significance of an additional chromosomal abnormality (ACA), variant Philadelphia chromosome (vPh) at diagnosis, and newly developed other chromosomal abnormalities (OCA) in patients with chronic myeloid leukemia (CML) on imatinib (IM) therapy. Sequential cytogenetic data from 281 consecutive new chronic phase CML patients were analyzed. With a median follow-up of 78.6 months, the 22 patients with vPh (P = 0.034) or ACA (P = 0.034) at diagnosis had more events of IM failure than did the patients with a standard Ph. The 5-year overall survival (OS), event-free survival (EFS), and failure-free survival (FFS) rates for patients with vPh at diagnosis were 77.8%, 75.0%, and 53.3%, respectively; for patients with ACA at diagnosis, 100%, 66.3%, and 52.1%, respectively; and for patients with a standard Ph, 96.0%, 91.3%, and 83.7%, respectively. During IM therapy, eight patients developed an OCA, which had no impact on outcomes as a time-dependent covariate in our Cox proportional hazards regression models. This study showed that vPh was associated with poor OS and FFS and that ACA had adverse effects on EFS and FFS. In addition, no OCA, except monosomy 7, had any prognostic impact, suggesting that the development of OCA may not require a change in treatment strategy.

The IFNG (IFN-gamma) genotype predicts cytogenetic and molecular response to imatinib therapy in chronic myeloid leukemia.

PURPOSE: The present study analyzed treatment outcomes of imatinib therapy by interindividual genetic variants in candidate biological pathways of chronic myeloid leukemia (CML) such as apoptosis, angiogenesis, IFN-γ signaling pathways, or drug transport/metabolism of imatinib. EXPERIMENTAL DESIGN: Peripheral blood DNAs were genotyped for 79 single nucleotide polymorphism markers involved in the pathways of apoptosis, angiogenesis, myeloid cell growth, xenobiotic metabolism, WT1 signaling, IFN signaling, and others in CML patients who were included in discovery (n = 229, Canada) and validation cohorts (n = 187, Korea). RESULTS: We found several genotypes associated with complete cytogenetic response: IFNG (rs1861494, rs2069705), FASL (rs763110), FAS (rs2234767, rs2234978), VEGFR2 (rs1531289), and WT1 (rs2234590); with major molecular response: IFNG (rs1861494, rs2069705), BIRC5 (rs9904341), FAS (rs2234978), and ABCG2 (rs2231142); with loss of response: IFNG (rs2069705), IFNGR2 (rs9808753), BIRC5 (rs9904341), and ORM (rs3182041); and with treatment failure: IFNG (rs2069705), JAK3 (rs3212713), and ORM (rs3182041). External validation for the above significant genotypes confirmed that the IFNG genotype (rs2069705) was predictive of complete cytogenetic response (hazard ratio, 2.17; P < 0.001) and major molecular response (hazard ratio, 1.96; P = 0.0001) in validation cohorts of Korean ethnicity. CONCLUSIONS: The IFNG genotype was predictive for response to imatinib therapy, suggesting potential involvement of the IFN-γ signaling pathway in the mechanism of action of imatinib in CML.