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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Prognostic factors were studied in a series of 211 acute myeloid leukaemia (AML) patients over 60 years of age, treated at a single centre. The patients were allocated into three risk groups based on cytogenetics, occurrence of antecedent haematological disorder and leucocyte count. Only 3% had low‐risk features, 39% had intermediate‐ and 58% had adverse‐risk features. Complete remission (CR) was achieved in 43% of all patients. In multivariate analyses, the number of cycles needed to achieve CR and the risk group were significantly associated with the duration of CR. Median survival time for the entire cohort of patients was only 107 d. Advanced age, low induction treatment intensity, treatment during earlier years and adverse‐risk group were associated with shorter overall survival times. Risk group classification may help selection of elderly patients with a good chance of benefiting from intensive treatment to actually receive such treatment, while sparing others with a low probability of survival benefit from toxic treatment. Low intensity induction treatment reduces the chance of obtaining complete remission, produces inferior survival times and should consequently be avoided when the aim is to obtain complete remission. In elderly AML patients, introducing age and re‐evaluation of intermediate and good prognosis patients regarding response to induction treatment may improve the risk group classification.

A number of genes are involved in iron metabolism, including the transferrin receptor (TFR) and haemochromatosis (HFE) genes. In previous investigations an increased risk for neoplastic disease has been observed in individuals homo- and heterozygous for hereditary haemochromatosis. The HFE wild-type gene product complexes with the transferrin receptor (TF) and two different HFE mutations (Cys282Tyr and His63Asp) have been found to increase the affinity of TFR for TF and increase cellular iron uptake. In a recent study we found no associations for HFE and TFR separately, but an interaction between HFE and TFR genotypes in multiple myeloma. Individuals carrying the HFE Tyr282 allele (homo- and heterozygotes) in combination with homozygosity for the TFR Ser142 allele had an increased risk. In the present study the same association was found in breast and colorectal cancer. The odds ratio for all three neoplasms combined was 2.0 (95% CI 1.0-3.8). The risk for neoplastic disease was further increased (OR 7.7, 95% CI = 1.0-59.9) when the analysis was restricted to HFE Tyr homozygotes and compound heterozygotes in combination with TFR Ser homozygosity. Thus, an interaction between HFE and TFR alleles may increase the risk for different neoplastic disorders.

Chronic myeloid leukemia (CML) stem cells appear resistant to tyrosine kinase inhibitors (TKIs) in vitro, but their impact and drug sensitivity in vivo has not been systematically assessed. We prospectively analyzed the proportion of Philadelphia chromosome-positive leukemic stem cells (LSCs, Ph+CD34+CD38-) and progenitor cells (LPCs, Ph+CD34+CD38+) from 46 newly diagnosed CML patients both at the diagnosis and during imatinib or dasatinib therapy (ClinicalTrials.gov NCT00852566). At diagnosis, the proportion of LSCs varied markedly (1-100%) between individual patients with a significantly lower median value as compared with LPCs (79% vs 96%, respectively, P=0.0001). The LSC burden correlated with leukocyte count, spleen size, hemoglobin and blast percentage. A low initial LSC percentage was associated with less therapy-related hematological toxicity and superior cytogenetic and molecular responses. After initiation of TKI therapy, the LPCs and LSCs rapidly decreased in both therapy groups, but at 3 months time point the median LPC level was significantly lower in dasatinib group compared with imatinib patients (0.05% vs 0.68%, P=0.032). These data detail for the first time the prognostic significance of the LSC burden at diagnosis and show that in contrast to in vitro data, TKI therapy rapidly eradicates the majority of LSCs in patients.