Dasatinib combined with interferon-alfa induces a complete cytogenetic response and major molecular response in a patient with chronic myelogenous leukemia harboring the T315I BCR-ABL1 mutation

Ponatinib in chronic myeloid leukemia (CML): Consensus on patient treatment and management from a European expert panel

Five tyrosine kinase inhibitors (TKIs) are currently approved in the European Union for treatment of chronic myeloid leukemia (CML) and all have considerable overlap in their indications. While disease-specific factors such as CML phase, mutational status, and line of treatment are key to TKI selection, other important features must be considered, such as patient-specific comorbidities and TKI safety profiles. Ponatinib, the TKI most recently approved, has demonstrated efficacy in patients with refractory CML, but is associated with an increased risk of arterial hypertension, sometimes severe, and serious arterial occlusive and venous thromboembolic events. A panel of European experts convened to discuss their clinical experience in managing patients with CML. Based on the panel discussions, scenarios in which a CML patient may be an appropriate candidate for ponatinib therapy are described, including presence of the T315I mutation, resistance to other TKIs without the T315I mutation, and intolerance to other TKIs.

Deep molecular response by IFN-α and dasatinib combination in a patient with T315I-mutated chronic myeloid leukemia

The T315I mutation is especially challenging as it confers resistance to all first- and second-generation tyrosine kinase inhibitors. We present here a chronic myeloid leukemia patient harboring the T315I and E255V BCR-ABL1 mutation successfully achieved deep molecular response with a combined treatment of dasatinib and IFN-α. To our knowledge, this is the second case of a T315I-bearing chronic myeloid leukemia patient displaying satisfactory response to the combination therapy of dasatinib and IFN-α.

Mechanisms of resistance to BCR-ABL TKIs and the therapeutic strategies: A review

BCR-ABL caused by the translocation of t(9,22) with elevated tyrosine-kinase activity could induce leukemia in mice, which established BCR-ABL as the molecular pathogenic event in CML (Chronic myeloid leukemia). In recent years, a variety of tyrosine kinase inhibitors (TKIs) targeting at BCR-ABL specifically and effectively have been developed, which has fundamentally promoted the treatment of CML. However, the efficacy of TKIs was limited by its resistance induced by the development of kinase domain mutations and other mechanisms illustrated. In this review, we summarized BCR-ABL inhibitors approved by Food and Drug Administration (FAD), with the same concerns focus on the resistant mechanisms of BCR-ABL inhibitors and therapeutic resistant strategies.

Immunology and immunotherapy of chronic myeloid leukemia

Chronic myeloid leukemia (CML) is a clonal bone marrow stem cell neoplasia known to be responsive to immunotherapy. Despite the success of tyrosine kinase inhibitors (TKIs) targeting the BCR-ABL1 oncokinase, patients are not considered to be cured with the current therapy modalities. However, there have been recent advancements in understanding the immunobiology of the disease (such as tumor specific antigens and immunostimulatory agents), and this may lead to the development of novel, curative treatment strategies. Already there are promising results showing that a small proportion of CML patients are able to discontinue the therapy although they have a minimal amount of residual leukemia cells left. This implies that the immune system is able to restrain the tumor cell expansion. In this review, we aim to give a brief update of the novel aspects of the immune system in CML patients and of the developing strategies for controlling CML by the means of immunotherapy.

Resistance to tyrosine kinase inhibition therapy for chronic myelogenous leukemia: a clinical perspective and emerging treatment options

The development of tyrosine kinase inhibitors (TKIs) has led to extended lifespans for many patients with chronic myelogenous leukemia (CML). However, 20% to 30% of patients fail to respond, respond suboptimally, or experience disease relapse after treatment with imatinib. A key factor is drug resistance. The molecular mechanisms implicated in this resistance include those that involve upregulation or mutation of BCR-ABL kinase and those that are BCR-ABL independent. The clinical consequences of these molecular mechanisms of resistance for disease pathogenesis remain open for debate. This review summarizes the molecular mechanisms and clinical consequences of TKI resistance and addresses the current and future treatment approaches for patients with TKI-resistant CML.

Re-emergence of interferon-α in the treatment of chronic myeloid leukemia

Treatment for chronic myeloid leukemia (CML) has evolved from chemotherapy (busulfan, hydroxyurea) to interferon-α (IFNα), and finally to tyrosine kinase inhibitors such as imatinib. Although imatinib has profoundly improved outcomes for patients with CML, it has limitations. Most significantly, imatinib cannot eradicate CML primitive progenitors, which likely accounts for the high relapse rate when imatinib is discontinued. IFNα, unlike imatinib, preferentially targets CML stem cells. Early studies with IFNα in CML demonstrated its ability to induce cytogenetic remission. Moreover, a small percentage of patients treated with IFNα were able to sustain durable remissions after discontinuing therapy and were probably cured. The mechanisms by which IFNα exerts its antitumor activity in CML are not well understood; however, activation of leukemia-specific immunity may have a role. Some clinical studies have demonstrated that the combination of imatinib and IFNα is superior to either therapy alone, perhaps because of their different mechanisms of action. Nonetheless, the side effects of IFNα often impede its administration, especially in combination therapy. Here, we review the role of IFNα in CML treatment and the recent developments that have renewed interest in this once standard therapy for patients with CML.