Recent studies suggest that a proportion of chronic myeloid leukemia (CML) patients in deep molecular remission can discontinue the tyrosine kinase inhibitor (TKI) treatment without disease relapse. In this multi-center, prospective clinical trial (EURO-SKI, NCT01596114) we analyzed the function and phenotype of T and NK cells and their relation to successful TKI cessation. Lymphocyte subclasses were measured from 100 imatinib-treated patients at baseline and 1 month after the discontinuation, and functional characterization of NK and T cells was done from 45 patients. The proportion of NK cells was associated with the molecular relapse-free survival as patients with higher than median NK-cell percentage at the time of drug discontinuation had better probability to stay in remission. Similar association was not found with T or B cells or their subsets. In non-relapsing patients the NK-cell phenotype was mature, whereas patients with more naïve CD56bright NK cells had decreased relapse-free survival. In addition, the TNF-α/IFN-γ cytokine secretion by NK cells correlated with the successful drug discontinuation. Our results highlight the role of NK cells in sustaining remission and strengthen the status of CML as an immunogenic tumor warranting novel clinical trials with immunomodulating agents.

The risk of AML/MDS development after MPN diagnosis was significantly associated with high exposures of P(32) and alkylators but not with HU treatment. Twenty-five percent of patients with MPNs who developed AML/MDS were not exposed to cytotoxic therapy, supporting a major role for nontreatment-related factors.

Key Points• Patients up to age 70 years with CML treated within a decentralized health care setting had a relative survival close to 1.0. • Sokal, but not EUTOS, score at diagnosis predicted overall and relative survival in a population-based cohort of patients with CML.Clinical management guidelines on malignant disorders are generally based on data from clinical trials with selected patient cohorts. In Sweden, more than 95% of all patients diagnosed with chronic myeloid leukemia (CML) are reported to the national CML registry, providing unique possibilities to compile population-based information. This report is based on registry data from 2002 to 2010, when a total of 779 patients (425 men, 354 women; median age, 60 years) were diagnosed with CML (93% chronic, 5% accelerated, and 2% blastic phase) corresponding to an annual incidence of 0.9/100 000. In 2002, approximately half of the patients received a tyrosine kinase inhibitor as initial therapy, a proportion that increased to 94% for younger (<70 years) and 79% for older (>80 years) patients during [2007][2008][2009]. With a median follow-up of 61 months, the relative survival at 5 years was close to 1.0 for patients younger than 60 years and 0.9 for those aged 60 to 80 years, but only 0.6 for those older than 80 years. At 12 months, 3% had progressed to accelerated or blastic phase. Sokal, but not European Treatment and Outcome Study, high-risk scores were significantly linked to inferior overall and relative survival. Patients living in university vs nonuniversity catchment areas more often received tyrosine kinase inhibitors up front but showed comparable survival. (Blood. 2013;122(7):1284-1292

Biologic and clinical observations suggest that combining imatinib with IFN-␣ may improve treatment outcome in chronic myeloid leukemia (CML). We randomized newly diagnosed chronic-phase CML patients with a low or intermediate Sokal risk score and in imatinib-induced complete hematologic remission either to receive a combination of pegylated IFN␣2b (Peg-IFN-␣2b) 50 g weekly and imatinib 400 mg daily (n ‫؍‬ 56) or to receive imatinib 400 mg daily monotherapy (n ‫؍‬ 56). The primary endpoint was the major molecular response (MMR) rate at 12 months after randomization. In both arms, 4 patients (7%) discontinued imatinib treatment (1 because of blastic transformation in imatinib arm). In addition, in the combination arm, 34 patients (61%) discontinued Peg-IFN-␣2b, most because of toxicity. The MMR rate at 12 months was significantly higher in the imatinib plus Peg-IFN-␣2b arm (82%) compared with the imatinib monotherapy arm (54%; intention-to-treat, P ‫؍‬ .002). The MMR rate increased with the duration of Peg-IFN␣2b treatment (< 12-week MMR rate 67%, > 12-week MMR rate 91%). Thus, the addition of even relatively short periods of Peg-IFN-␣2b to imatinib markedly increased the MMR rate at 12 months of therapy. Lower doses of Peg-IFN-␣2b may enhance tolerability while retaining efficacy and could be considered in future protocols with curative intent. (Blood. 2011;118(12):3228-3235)

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