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In chronic myeloid leukemia (CML), combination therapies with tyrosine kinase inhibitors (TKIs) aim to improve the achievement of deep molecular remission that would allow therapy discontinuation. IFN-alpha is one promising candidate, as it has long-lasting effects on both malignant and immune cells. In connection with a multicenter clinical trial combining dasatinib with IFN-alpha in 40 patients with chronic-phase CML (NordCML007, NCT01725204), we performed immune monitoring with single-cell RNA and T cell receptor (TCR) sequencing (n = 4, 12 samples), bulk TCR beta sequencing (n = 13, 26 samples), flow cytometry (n = 40, 106 samples), cytokine analyses (n = 17, 80 samples), and ex vivo functional studies (n = 39, 80 samples). Dasatinib drove the immune repertoire toward terminally differentiated NK and CD8+ T cells with dampened functional capabilities. Patients with dasatinib-associated pleural effusions had increased numbers of CD8(+) recently activated effector memory T (Temra) cells. In vitro, dasatinib prevented CD3-induced cell death by blocking TCR signaling. The addition of IFN-alpha reversed the terminally differentiated phenotypes and increased the number of costimulatory intercellular interactions and the number of unique putative epitope-specific TCR clusters. In vitro IFN-alpha had costimulatory effects on TCR signaling. Our work supports the combination of IFN-alpha with TKI therapy, as IFN-alpha broadens the immune repertoire and restores immunological function., De två första författarna delar förstaförfattarskapet.

Clinical trials show that tyrosine kinase inhibitor (TKI) treatment can be discontinued in selected patients with chronic myeloid leukaemia (CML). Although updated CML guidelines support such procedure in clinical routine, data on TKI stopping outside clinical trials are limited. In this retrospective study utilising the Swedish CML registry, we examined TKI discontinuation in a population-based setting. Out of 584 patients diagnosed with chronic-phase CML (CML-CP) in 2007-2012, 548 had evaluable information on TKI discontinuation. With a median follow-up of nine years from diagnosis, 128 (23%) discontinued TKI therapy (>= 1 month) due to achieving a DMR (deep molecular response) and 107 (20%) due to other causes (adverse events, allogeneic stem cell transplant, pregnancy, etc). Among those stopping in DMR, 49% re-initiated TKI treatment (median time to restart 4 center dot 8 months). In all, 38 patients stopped TKI within a clinical study and 90 outside a study. After 24 months 41 center dot 1% of patients discontinuing outside a study had re-initiated TKI treatment. TKI treatment duration pre-stop was longer and proportion treated with second-generation TKI slightly higher outside studies, conceivably affecting the clinical outcome. In summary we show that TKI discontinuation in CML in clinical practice is common and feasible and may be just as successful as when performed within a clinical trial.

We recently reported an increased incidence of second malignancies in chronic myeloid leukemia (CML) patients treated with tyrosine kinase inhibitors (TKI). To elucidate whether this increase may be linked, not to TKI but rather to a hereditary or acquired susceptibility to develop cancer, we estimated the prevalence of malignancies, autoimmune disease (AD) and chronic inflammatory disease (CID) in CML patients prior to their CML diagnosis. Nationwide population-based registers were used to identify patients diagnosed with CML in Sweden 2002-2012 and to estimate the prevalence of other malignancies, AD and CID prior to their CML diagnosis. For each patient with CML, five matched controls were selected from the general population. Conditional logistic regression was used to calculate odds ratios (OR). Nine hundred and eighty-four CML patients were assessed, representing more than 45 000 person-years of follow-up. Compared with matched controls, the prevalence of prior malignancies and AD was elevated in CML patients: OR 1.47 (95% confidence interval (CI) 1.20-1.82) and 1.55 (95% CI 1.21-1.98), respectively. No associations were detected between CML and previous CID. An increased prevalence of other malignancies and AD prior to the diagnosis of CML suggest that a hereditary or acquired predisposition to cancer and/or autoimmunity is involved in the pathogenesis of CML.

Immune escape mechanisms promote tumor progression and are hurdles of cancer immunotherapy. Removing immunosuppressive cells before treatment can enhance efficacy. Tyrosine kinase inhibitors (TKI) may be of interest to combine with immunotherapy, as it has been shown that the inhibitor sunitinib reduces myeloid suppressor cells in patients with renal cell carcinoma and dasatinib promotes expansion of natural killer-like lymphocytes in chronic myeloid leukemia (CML). In this study, the capacity of dasatinib and imatinib to reduce myeloid suppressor cells and to induce immunomodulation in vivo was investigated ex vivo. Samples from CML patients treated with imatinib (n = 18) or dasatinib (n = 14) within a Nordic clinical trial (clinicalTrials.gov identifier: NCT00852566) were investigated for the presence of CD11b(+)CD14(-)CD33(+) myeloid cells and inhibitorymolecules (arginase I, myeloperoxidase, IL10) as well as the presence of natural killer cells, T cells (naive/memory), and stimulatory cytokines (IL12, IFN gamma, MIG, IP10). Both imatinib and dasatinib decreased the presence of CD11b(+)CD14(-)CD33(+) myeloid cells as well as the inhibitory molecules and the remaining myeloid suppressor cells had an increased CD40 expression. Monocytes also increased CD40 after therapy. Moreover, increased levels of CD40, IL12, natural killer cells, and experienced T cells were noted after TKI initiation. The presence of experienced T cells was correlated to a higher IFNg and MIG plasma concentration. Taken together, the results demonstrate that both imatinib and dasatinib tilted the immunosuppressive CML tumor milieu towards promoting immune stimulation. Hence, imatinib and dasatinib may be of interest to combine with cancer immunotherapy. (C) 2015 AACR.

OBJECTIVES: During long term follow-up of a cohort of patients with essential thrombocythemia (ET) and polycythemia vera (PV) a higher than expected incidence of myelofibrosis (MF) was noted. In order to test if the explanation could be found in the diagnostic criteria a re-evaluation of diagnosis using the 2008 WHO diagnostic criteria for ET and MF was performed. METHODS: This prospective study of 60 patients with ET and PV was set up in 1998 to evaluate the long-term efficacy and tolerability of anagrelide treatment. Bone marrow trephine biopsies were requested from study start, after 2 and 7 years of follow-up. A blinded re-evaluation of the bone marrow trephines was performed. The 2008 WHO bone marrow criteria were used for diagnosis and fibrosis grading. RESULTS: Of 40 patients with an initial diagnosis of ET, 21 were confirmed as 'true ET' whereas 17 were reclassified as primary myelofibrosis (PMF) (12 PMF-0, 3 PMF-1, 2 PMF-2) and 2 as myeloproliferative neoplasms of uncertain origin. After 7 years of follow-up, 19 of 21 patients with 'true ET' were alive, none had transformed to MF, leukemia, or myelodysplastic syndrome. In contrast, 4/17 patients reclassified as PMF had died, two patients transformed to myelodysplastic syndrome and 7 patients progressed to overt MF. DISCUSSION: We conclude that a blinded re-evaluation of bone marrow trephines from study start and after 7 years of follow-up using 2008 World Health Organization criteria was able to differentiate between true ET and PMF with a marked difference in follow-up outcome.

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 2007-2009. 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.

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.

Biologic and clinical observations suggest that combining imatinib with IFN-a 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-a2b (Peg-IFN-a2b) 50 µg 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-a2b, most because of toxicity. The MMR rate at 12 months was significantly higher in the imatinib plus Peg-IFN-a2b arm (82%) compared with the imatinib monotherapy arm (54%; intention-to-treat, P = .002). The MMR rate increased with the duration of Peg-IFN-a2b treatment (<12-week MMR rate 67%, > 12-week MMR rate 91%). Thus, the addition of even relatively short periods of Peg-IFN-a2b to imatinib markedly increased the MMR rate at 12 months of therapy. Lower doses of Peg-IFN-a2b may enhance tolerability while retaining efficacy and could be considered in future protocols with curative intent.

PURPOSE: Patients with myeloproliferative neoplasms (MPNs), including polycythemia vera, essential thrombocythemia, and primary myelofibrosis, have a propensity to develop acute myeloid leukemia (AML) and myelodysplastic syndromes (MDSs). Using population-based data from Sweden, we assessed the role of MPN treatment and subsequent AML/MDS risk with special focus on the leukemogenic potential of hydroxyurea (HU). METHODS: On the basis of a nationwide MPN cohort (N = 11,039), we conducted a nested case-control study, including 162 patients (153 and nine with subsequent AML and MDS diagnosis, respectively) and 242 matched controls. We obtained clinical and MPN treatment data for all patients. Using logistic regression, we calculated odds ratios (ORs) as measures of AML/MDS risk. RESULTS: Forty-one (25%) of 162 patients with MPNs with AML/MDS development were never exposed to alkylating agents, radioactive phosphorous (P(32)), or HU. Compared with patients with who were not exposed to HU, the ORs for 1 to 499 g, 500 to 999 g, more than 1,000 g of HU were 1.5 (95% CI, 0.6 to 2.4), 1.4 (95% CI, 0.6 to 3.4), and 1.3 (95% CI, 0.5 to 3.3), respectively, for AML/MDS development (not significant). Patients with MPNs who received P(32) greater than 1,000 MBq and alkylators greater than 1 g had a 4.6-fold (95% CI, 2.1 to 9.8; P = .002) and 3.4-fold (95% CI, 1.1 to 10.6; P = .015) increased risk of AML/MDS, respectively. Patients receiving two or more cytoreductive treatments had a 2.9-fold (95% CI, 1.4 to 5.9) increased risk of transformation. CONCLUSION: 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.

Biologic and clinical observations suggest that combining imatinib with IFN-alpha 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-alpha 2b (Peg-IFN-alpha 2b) 50 mu 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-alpha 2b, most because of toxicity. The MMR rate at 12 months was significantly higher in the imatinib plus Peg-IFN-alpha 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-alpha 2b treatment (< 12-week MMR rate 67%, > 12-week MMR rate 91%). Thus, the addition of even relatively short periods of Peg-IFN-alpha 2b to imatinib markedly increased the MMR rate at 12 months of therapy. Lower doses of Peg-IFN-alpha 2b may enhance tolerability while retaining efficacy and could be considered in future protocols with curative intent.

Anagrelide is often used in the treatment of thrombocythemia in myeloproliferative disease (MPD), but information concerning effects of treatment on cytokines involved in regulation of blood platelet levels is limited. Here, we investigated serum levels of thrombopoietin (TPO) and soluble IL-6 receptor (sIL-6R) in relation to response to treatment with and plasma concentrations of anagrelide. Samples from 45 patients with thrombocythemia due to MPD (ET=31, PV=14), being treated with anagrelide for 6 months, were analyzed for TPO, sIL-6R and anagrelide levels. The mean baseline platelet count was 983x10(9)/L. A reduction of platelets to <600 in asymptomatic or <400 x 10(9)/L in symptomatic patients was defined as a complete remission (CR), a reduction with >50% of baseline as partial remission, and <50% reduction as failure. At 6 months, 35 patients were in CR, 1 had a partial remission and 9 were treatment failures. For all patients, there was an increase in TPO of 44% from baseline; this change was more pronounced for patients with partial remission and failure. sIL-6R levels did not change significantly. There was no correlation between levels of anagrelide and cytokine levels at 6 months, and changes of cytokine levels did not relate to changes of platelet counts. Thus, a pronounced increase of TPO levels after 6 months of anagrelide treatment indicated that this treatment affected a major regulatory mechanism for megakaryocyte and platelet formation in MPD.

Using a quantitative single nucleotide polymorphism (SNP) assay we have investigated the changes in the expression of the BCR-ABL1 oncogene relative to the wild-type ABL1 and BCR alleles in cells from chronic myeloid leukemia (CML) patients not responding to therapy. The results show a progressive increase in the BCR-ABL1 oncogene expression at the expense of decreased expression of the ABL1 allele, not involved in the fusion. No relative changes in the expression of the two BCR alleles were found. These results demonstrate that allele-specific changes in gene expression, with selective, progressive silencing of the wild-type ABL1 allele in favor of the oncogenic BCR-ABL1 allele occur in CML patients with therapy-resistant disease.