Mahon FX, Rea D, Guilhot J, Guilhot F, Huguet F, Nicolini F, Legros L, Charbonnier A, Guerci A, Varet B, Etienne G, Reiffers J, Rousselot P. Discontinuation of imatinib in patients with chronic myeloid leukaemia who have maintained complete molecular remission for at least 2 years: the prospective, multicentre Stop Imatinib (STIM) trial. Lancet Oncol. 11: 1029-1035

Laboratoire d'Hématologie et Service des Maladies du Sang, Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France.
The Lancet Oncology (Impact Factor: 24.69). 10/2010; 11(11):1029-35. DOI: 10.1016/S1470-2045(10)70233-3
Source: PubMed


Imatinib treatment significantly improves survival in patients with chronic myeloid leukaemia (CML), but little is known about whether treatment can safely be discontinued in the long term. We aimed to assess whether imatinib can be discontinued without occurrence of molecular relapse in patients in complete molecular remission (CMR) while on imatinib.
In our prospective, multicentre, non-randomised Stop Imatinib (STIM) study, imatinib treatment (of >2 years duration) was discontinued in patients with CML who were aged 18 years and older and in CMR (>5-log reduction in BCR-ABL and ABL levels and undetectable transcripts on quantitative RT-PCR). Patients who had undergone immunomodulatory treatment (apart from interferon α), treatment for other malignancies, or allogeneic haemopoietic stem-cell transplantation were not included. Patients were enrolled at 19 participating institutions in France. In this interim analysis, rate of relapse was assessed by use of RT-PCR for patients with at least 12 months of follow-up. Imatinib was reintroduced in patients who had molecular relapse. This study is registered with, number NCT00478985.
100 patients were enrolled between July 9, 2007, and Dec 17, 2009. Median follow-up was 17 months (range 1-30), and 69 patients had at least 12 months follow-up (median 24 months, range 13-30). 42 (61%) of these 69 patients relapsed (40 before 6 months, one patient at month 7, and one at month 19). At 12 months, the probability of persistent CMR for these 69 patients was 41% (95% CI 29-52). All patients who relapsed responded to reintroduction of imatinib: 16 of the 42 patients who relapsed showed decreases in their BCR-ABL levels, and 26 achieved CMR that was sustained after imatinib rechallenge.
Imatinib can be safely discontinued in patients with a CMR of at least 2 years duration. Imatinib discontinuation in this setting yields promising results for molecular relapse-free survival, raising the possibility that, at least in some patients, CML might be cured with tyrosine kinase inhibitors.

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    • "Overall, these studies show a probability of stable undetectable molecular response (MR) of approximately 40% at 24 months. Factors associated with sustained response are lower Sokal risk score, duration of imatinib treatment, previous interferon therapy, early major MR and duration of undetectable MR [2-4]. "
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    ABSTRACT: Introduction Although there is a considerable amount of data in the literature on safe discontinuation of first-generation tyrosine kinase inhibitor therapy in patients with chronic myeloid leukemia, little is known about discontinuation of second-generation tyrosine kinase inhibitor therapy. Most previous studies have been focused on dasatinib, and the few cases of nilotinib withdrawal that have been reported had a median follow-up of 12 months. To the best of our knowledge, the present report is the first to describe nilotinib withdrawal with 30 months of follow-up. Case presentation We report the case of a 64-year-old Caucasian man diagnosed with chronic-phase chronic myeloid leukemia in April 2005. After 4 years of treatment with imatinib, he became intolerant to the drug and was switched to nilotinib. Two years later, he decided to stop nilotinib. Undetectable molecular response persisted for 30 months after discontinuation of the drug. Conclusion Our present case suggests that nilotinib withdrawal is safe for patients with chronic myeloid leukemia who achieve a stable undetectable molecular response. Our patient was homozygous for killer immunoglobulin-like receptor haplotype A, previously reported to be a promising immunogenetic marker for undetectable molecular response. We recommend additional studies to investigate patient immunogenetic profiles and their potential role in complete response to therapy.
    Journal of Medical Case Reports 09/2014; 8(1):295. DOI:10.1186/1752-1947-8-295
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    • "The tyrosine kinase inhibitors (TKIs), imatinib (IM), nilotinib and dasatinib have changed the course of the chronic myeloid leukemia (CML) [1] but these drugs are not able to eradicate CML clone [2]. However, a study with patients discontinuing IM has shown that 41 percent of the patients stopping treatment while in complete molecular response (CMR), remained in CMR at 12 months of follow-up [3]. In these patients, it is possible that the immune system plays a role in maintaining complete remission. "
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    ABSTRACT: Tumor immune tolerance can derive from the recruitment of suppressor cell population, including myeloid derived suppressor cells (MDSCs), able to inhibit T cells activity. We identified a significantly expanded MDSCs population in chronic myeloid leukemia (CML) patients at diagnosis that decreased to normal levels after imatinib therapy. In addition, expression of arginase 1 (Arg1) that depletes microenvironment of arginine, an essential aminoacid for T cell function, resulted in an increase in patients at diagnosis. Purified CML CD11b+CD33+CD14-HLADR- cells markedly suppressed normal donor T cell proliferation in vitro. Comparing CML Gr-MDSCs to autologous polymorphonuclear leukocytes (PMNs) we observed a higher Arg1 expression and activity in PMNs, together with an inhibitory effect on T cells in vitro. Our data indicate that CML cells create an immuno-tolerant environment associated to MDSCs expansion with immunosuppressive capacity mediated by Arg1. In addition, we demonstrated for the first time also an immunosuppressive activity of CML PMNs, suggesting a strong potential immune escape mechanism created by CML cells, which control the anti-tumor reactive T cells. MDSCs should be monitored in imatinib discontinuation trials to understand their importance in relapsing patients.
    PLoS ONE 07/2014; 9(7):e101848. DOI:10.1371/journal.pone.0101848 · 3.23 Impact Factor
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    • "The effect of imatinib cessation on disease course is still under study, but most studies report disease relapse after imatinib discontinuation, with only a fraction of patients achieving complete remission after readministration of imatinib (Ault et al, 2006). However , for those patients with durable CMR (at least 2 years) a more favourable situation exists, with studies demonstrating disease control following reintroduction of TKI (Mahon et al, 2010). At present the data on 2G TKIs is too limited to make specific recommendations, but they also seem teratogenic (Cortes et al, 2008). "
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    ABSTRACT: Chronic myeloid leukaemia in children and young people is a relatively rare form of leukaemia that shows increased incidence with age and some evidence suggests that the molecular basis differs from that in adults. Significant advances in targeted therapy with the development and use in children of tyrosine kinase inhibitors and the ability to monitor and understand the prognostic significance of minimal residual disease by standardized molecular techniques has shifted the management of this condition from bone marrow transplantation as the main therapeutic modality to individualized treatment for each patient based on achieving specific milestones. The physiological changes occurring during childhood, particularly those affecting growth and development and the long-term use of treatment, pose specific challenges in this age group, which we are only beginning to understand.
    British Journal of Haematology 06/2014; 167(1). DOI:10.1111/bjh.12977 · 4.71 Impact Factor
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