Imatinib-intolerant Chronic Myeloid Leukemia Research Articles

Second-line Dasatinib Therapy Improved Compliance and Deep Molecular Responses in Imatinib-intolerant Chronic Myeloid Leukemia Patients.

Imatinib (IM) is the standard-of-care treatment for most chronic myeloid leukemia (CML) patients in chronic phase (CP). However, some patients suffer from low-grade side-effects that, in the long run, severely affect the quality of life and require treatment discontinuation due to toxicities. Fortunately, there are several therapeutic alternatives for these patients. Among them, the second-generation tyrosine kinase inhibitor dasatinib (DAS), used as second-line treatment, has shown to be a valid option in patients with CP-CML after intolerance to prior IM. Herein, we report on seven CP-CML patients who achieved a stable major molecular response (MMR) with IM-therapy, but were shifted to DAS treatment due to recurrent low-grade IM-intolerances (grades 1-2). All patients received conventional DAS treatment with a median daily dose of 83.3 mg. Treatment was well tolerated and side-effects were mild. In addition, after a median follow-up of 25 months (range=24-43 months) a deep molecular response (DMR) (either MR4 or MR4.5) was achieved in all patients after 24 months of treatment. This finding, although limited to a small cohort of CP-CML patients, supports the view that a therapy switch from IM to DAS induces a reduction of symptom burden, improves patient compliance and shows clinical efficacy in achieving and sustaining deep molecular responses.

Sustained molecular response with nilotinib in imatinib-intolerant chronic myeloid leukaemia with an e19a2 BCR-ABL1 fusion

Sustained molecular response with nilotinib in imatinib-intolerant chronic myeloid leukaemia with an e19a2 BCR-ABL1 fusion

Nilotinib therapy in an imatinib intolerant chronic myeloid leukemia patient with pulmonary severe hypertension

Imatinib mesylate is a tyrosine kinase inhibitor that has significant efficacy in the treatment of chronic myelogenous leukemia. In general, hematologic and extrahematologic side effects of imatinib therapy are mild to moderate, with the large majority of patients tolerating prolonged periods of therapy. However, a minority of patients are completely intolerant of therapy, while others are able to remain on therapy despite significant side effects. Here, we describe a chronic phase CML patient with pulmonary arterial hypertension, mechanical hearth valve, who experienced extrahematologic adverse event (persistent grade III cutaneous rash, despite two discontinuations of imatinib and using of steroid). Necessitating switch to one of new tyrosine kinase inhibitors, nilotinib, has resulted in complete cytogenetic response and major molecular response, after 3 and 6 months, respectively. No cross-intolerance with imatinib was observed during nilotinib therapy. Besides, this clinical case suggests that warfarin and nilotinib can be used concurrently without the risk of increased anticoagulant effect.

Multicenter Phase II Clinical Trial of Nilotinib for Patients with Imatinib-Resistant or Intolerant CML From the East Japan CML Study Group (EJCML) Trial: Evaluation of Molecular Responses by the BCR-ABL1 Mutational Status and Plasma Trough Concentration of Nilotinib

AbstractAbstract 1360 Introduction:The tyrosine kinase inhibitor (TKI) imatinib is used as the first-line therapy for newly diagnosed chronic myeloid leukemia (CML). However, some patients fail to respond or become intolerant to imatinib. Nilotinib is a second-generation TKI with higher selectivity and more potent inhibitory effects on BCR-ABL than imatinib. Several studies have shown hematologic and cytogenetic responses to nilotinib in patients with imatinib-resistant or intolerant CML. Purpose:To investigate the safety and efficacy of nilotinib for patients with imatinib-resistant or intolerant, chronic (CP)- or accelerated (AP)-phase CML from the East Japan CML Study Group (EJCML) trial by evaluating molecular responses in terms of the BCR-ABL1 mutational status and plasma trough concentration of nilotinib. Methods:In this multicenter phase II clinical trial, nilotinib (400 mg bid) was administered orally for one year and the molecular responses were monitored by means of the international scale of quantitative PCR (IS-PCR). BCR-ABL1 mutations were analyzed by direct sequencing at the baseline and 12 months or at the time of the event for discontinuation of the treatment (i.e., progressive disease, insufficient effects, or severe adverse events). The plasma trough concentration of nilotinib was measured by high-performance liquid chromatography 3 months after nilotinib administration. Results:From March 2009 through February 2011, 51 patients were registered in this study, and data of 49 patients whose molecular responses were evaluated by the IS-PCR were analyzed (imatinib-resistant CML = 33, imatinib-intolerant CML = 16; CP CML = 46, AP CML = 3). The median follow-up period was 12.0 months (range = 0.1–13.3 months). At 6 and 12 months, the major molecular response (MMR; ≤0.1% IS) rates were 52.5% and 67.6%, respectively, and the complete cytogenetic response (CCyR)-equivalent (≤1.0% IS) rates were 75.0% and 85.3%, respectively. Five types of BCR-ABL1 mutations (M244V, F317L, N358D, F359V, and E459K) were detected in 6 patients (12.2%) at the baseline, but the M244V, N358D, and E459K mutations disappeared after the nilotinib treatment. Acquired BCR-ABL1 mutations (Y253H, I418V, and exon 8/9 35bp insertion) were detected in 3 patients (8.6%) at 12 months or at the time of the event; these patients did not achieve a CCyR or an MMR. No patients showed an acquired mutation of T315I. Most patients except 11 subjects (22.4%) still received the treatment. The reasons for discontinuation were progressive disease in one patient with an F317L mutation, insufficient effects in one patient without any mutation, and adverse events in 9 patients (thrombocytopenia in 5 patients, hyperbilirubinemia in 2 patients, headache in one patient, and heart disease in one patient). Among 30 patients without BCR-ABL1 mutations, the plasma trough concentration of nilotinib was significantly higher in 21 patients with an MMR than in those without an MMR by 12 months (median = 1255.1 ng/mL vs. 372.8 ng/mL, P = 0.0012 by Mann–Whitney U-test; see the figure). The concentration of 761 ng/mL was significantly associated with an MMR by 12 months in a receiver-operating characteristic (ROC) curve analysis of the best sensitivity (76.2%) and specificity (77.8%). Conclusion:The patients with imatinib-resistant or intolerant, CP or AP CML, even those having BCR-ABL1 mutations M244V, N358D, and E459K, achieved an MMR by 12 months of nilotinib treatment. The plasma trough concentration of the drug was related to the MMR by 12 months, and the plasma threshold of nilotinib should be set above 761 ng/mL. These findings suggest that nilotinib shows good efficacy and tolerability in Japanese patients with imatinib-resistant or intolerant, CP or AP CML. (ClicalTrials.gov, UMIN ID 000002201) [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Managing side effects of tyrosine kinase inhibitor therapy to optimize adherence in patients with chronic myeloid leukemia: the role of the midlevel practitioner.

In the last decade, the development of imatinib, a tyrosine kinase inhibitor, has brought about unprecedented change in the way newly diagnosed, chronic-phase chronic myeloid leukemia patients are treated. Two next-generation tyrosine kinase inhibitors, nilotinib and dasatinib, were initially indicated for imatinib-resistant or imatinib-intolerant chronic myeloid leukemia patients and recently received approval from the Food and Drug Administration for treatment of newly diagnosed, chronic-phase chronic myeloid leukemia patients. In comparison with the previous standards of care, benefits with these three tyrosine kinase inhibitors have included more rapid response rates, increased survival, and fewer side effects. The improved long-term outcomes have altered the approach to management of chronic myeloid leukemia from a progressive fatal disease with a poor prognosis to a chronic condition similar to diabetes or hypertension. Prolonged survival increases the need for patient education, support, monitoring, and assistance with adverse event management. Even low-grade side effects can adversely affect patients' quality of life and, therefore, require prompt attention to prevent long-term complications or suboptimal outcomes. New evidence has indicated that patient adherence to tyrosine kinase inhibitor therapy is essential to successful treatment. Midlevel practitioners can help to optimize outcomes by educating patients regarding the importance of adherence, performing regular monitoring, helping patients to understand their test results, and aggressively managing treatment-related side effects.

Safety and efficacy of bosutinib (SKI-606) in chronic phase Philadelphia chromosome–positive chronic myeloid leukemia patients with resistance or intolerance to imatinib

AbstractBosutinib, a dual Src/Abl kinase inhibitor, has shown potent activity against chronic myeloid leukemia (CML). In this phase 1/2 study we evaluated bosutinib in patients with chronic phase imatinib-resistant or imatinib-intolerant CML. Part 1 was a dose-escalation study to determine the recommended starting dose for part 2; part 2 evaluated the efficacy and safety of bosutinib 500 mg once-daily dosing. The study enrolled 288 patients with imatinib-resistant (n = 200) or imatinibintolerant (n = 88) CML and no other previous kinase inhibitor exposure. At 24 weeks, 31% of patients achieved major cytogenetic response (primary end point). After a median follow-up of 24.2 months, 86% of patients achieved complete hematologic remission, 53% had a major cytogenetic response (41% had a complete cytogenetic response), and 64% of those achieving complete cytogenetic response had a major molecular response. At 2 years, progression-free survival was 79%; overall survival at 2 years was 92%. Responses were seen across Bcr-Abl mutants, except T315I. Bosutinib exhibited an acceptable safety profile; the most common treatment-emergent adverse event was mild/moderate, typically self-limiting diarrhea. Grade 3/4 nonhematologic adverse events (> 2% of patients) included diarrhea (9%), rash (9%), and vomiting (3%). These data suggest bosutinib is effective and tolerable in patients with chronic phase imatinib-resistant or imatinib-intolerant CML. This trial was registered at http://www.clinicaltrials.gov as NCT00261846.

Lack of non-hematological cross intolerance of dasatinib to imatinib in imatinib-intolerant patients with Philadelphia chromosome positive chronic myeloid leukemia or acute lymphatic leukemia: a retrospective safety analysis

The aim of this retrospective study was to evaluate the toxicity profiles of dasatinib in patients with Philadelphia chromosome positive chronic myeloid leukemia (CML) or acute lymphatic leukemia (ALL) who were intolerant to imatinib, and who had been enrolled in our previous clinical trials to evaluate efficacy of dasatinib in patients resistant or tolerant to imatinib therapy. Twenty-four patients with CML and four with ALL were enrolled in the clinical studies to evaluate the efficacy according to the eligibility criteria related to intolerance to imatinib therapy. The toxicities reported during imatinib therapy were non-hematological toxicities in 23 patients and hematological toxicities in six patients. Patients were administered dasatinib 50-70 mg BID or 100 mg QD. Cross intolerance was observed in four patients who showed hematological toxicity after dasatinib treatment. However, it was possible to successfully continue therapy with only temporary interruption. No cross intolerance in non-hematological toxicity was found with the exception of one patient who showed cross intolerance, which did not result in treatment interruption. Dasatinib can be safely administered to imatinib-intolerant CML or Ph-positive ALL patients.

New Bcr-Abl inhibitors in chronic myeloid leukemia: keeping resistance in check

Targeted therapy with the Abl kinase inhibitor imatinib has markedly improved the outlook for patients with chronic myeloid leukemia (CML). Breakpoint cluster region (Bcr)-Abl signaling is reactivated at the time of resistance, predominantly due to mutations in the kinase domain of Bcr-Abl that interfere with drug binding. This discovery prompted the development of new Abl kinase inhibitors, among which nilotinib and dasatinib have gained regulatory approval. Despite excellent results in patients with imatinib-resistant or imatinib-intolerant CML treated with nilotinib or dasatinib, early indications suggest that: the cross-resistant Bcr-AblT315I mutant is disproportionately represented among patients who relapse on these therapies; each Abl inhibitor exhibits vulnerabilities to certain kinase domain mutations. We review new inhibitors of Bcr-Abl, including preliminary information on inhibitors of Bcr-AblT315I and discuss the potential of combined Abl kinase inhibitor therapy to pre-empt resistance. Improved Abl inhibitor therapies will be useful in achieving maximum disease control but a clinical T315I inhibitor remains a high priority.

Current Perspectives on the Treatment of Patients with Chronic Myeloid Leukemia: An Individualized Approach to Treatment

The BCR-ABL tyrosine kinase inhibitor imatinib has dramatically improved the prognosis for most patients with chronic myeloid leukemia (CML). Efforts to optimize therapy in CML have resulted in new and revised treatment guidelines or algorithms, which are reviewed here. Data were identified by searches of MEDLINE, PubMed, and references from relevant articles using the terms "chronic myeloid leukemia," "imatinib," and "tyrosine kinase inhibitors." Articles published in English between 1996 and 2006 were included. In this article we review consensus criteria for a therapeutic response and current expectations for CML therapy with imatinib, as well as the evidence supporting these recommendations. In addition, novel approaches to CML treatment are considered in light of the availability of second-generation tyrosine kinase inhibitors. With the advent of novel agents capable of treating imatinib-resistant or imatinib-intolerant CML, it should be possible in the future to further refine treatment algorithms.

Durable responses in chronic myeloid leukemia patients maintained with lower doses of imatinib mesylate after achieving molecular remission

In the present report, we address the question if the reduction of standard dosage of imatinib mesylate (IM) in imatinib-intolerant chronic myeloid leukemia (CML) patients with undetectable residual disease may impair their outcome. Four patients are described. The median follow up from the beginning of IM therapy was 35 months (33-59). The median duration of real-time quantitative polymerase chain reaction (RQ-PCR) negativity on IM 200 mg daily was 17 months (4-37). We hypothesize that in IM intolerant CML patients with complete molecular remission, the compound dosage might be safely reduced to a lower than standard dose without to lose the response. A tight molecular monitoring of such patients should be required.

Clonal Chromosomal Abnormalities in Philadelphia Negative Cells during Dasatinib Treatment in Five Patients with Chronic Myeloid Leukemia.

The emergence of clonal chromosomal abnormalities in Philadelphia negative cells was reported during Imatinib treatment in several patients with chronic myeloid leukemia (CML) in different phases (chronic phase, accelerated phase and blastic crisis). Recently, new tyrosine kinase inhibitors were used in treatment of Imatinib-resistant or Imatinib-intolerant chronic myeloid leukemia. We describe 5 patients with chromosomal abnormalities in Philadelphia negative cells during treatment with Dasatinib. At the beginning of treatment, 4 patients were in chronic phase, 1 patient was in accelerated phase. All patients were in cytogenetic relapse. Additional cytogenetic abnormalities were described in Philadelphia positive cells only in one case (accelerated phase). Clonal cytogenetic abnormalities (4 trisomy 8, 1 monosomy 7) appeared in Philadelphia negative cells during Dasatinib treatment (after 6 months in 1 patient, 9 months in 4 patients).At this time, 4 patients (Imatinib- resistant) received Dasatinib at the dose of 40 mg twice daily (dose reduction due to hematological toxicity); 1 patient (Imatinib cutaneous intolerance in chronic phase) received 140 mg daily. Two patients were in complete cytogenetic response, 2 patients were in partial cytogenetic response (10% and 8.5% Philadelphia positive cells) and obtained a complete cytogenetic response 3 months later, and 1 patient was in minor cytogenetic response. For 2 patients, the presence of trisomy 8 was transient, for 3 patients chromosomal abnormalities were persistent; none showed myelodysplastic changes. At present, all patients are still treated by Dasatinib with the same dosage. Cytogenetic abnormalities occur in Philadelphia negative cells in a fraction of patients with CML treated with Dasatinib. Philadelphia negative abnormal clone can persist despite complete cytogenetic response achievement. Their incidence, etiology and prognosis remain to be clarified and with a short follow-up, no clear clinical consequences can be identified.

A phase I study of BMS-354825 in patients with imatinib-resistant and intolerant chronic phase chronic myeloid leukemia (CML): Results from CA180002

6519 Background: Resistance to imatinib in CML patients is often associated with Bcr-Abl point mutations which interfere with imatinib binding. BMS-354825 is a novel, orally available, dual SRC/ABL kinase inhibitor with more than 300-fold greater potency than imatinib and has preclinical activity against 14 of 15 imatinib resistant Bcr-Abl mutants (Shah et al, Science, 305:399, 2004). Methods: CA180002 is a phase I, dose-escalation study of BMS-354825 in CML patients with hematologic resistance or intolerance to imatinib. Intrapatient dose escalation is permitted. Patient samples are analyzed for pharmacokinetics (PK), Bcr-Abl kinase domain mutations, and CRKL, HCK, and LYN phosphorylation. Results: 36 chronic phase CML patients have been treated (31 resistant, 5 intolerant) with total daily doses ranging from 15 - 180 mg (given as single or divided doses). Mutations associated with imatinib resistance were identified in 27 patients. Thirty-one patients (86%) have had complete hematologic response (CHR). Only 2 patients have had progression of their disease. Thirteen of 29 patients had cytogenetic improvement including 5 complete and 4 partial cytogenetic responses (i.e. major cytogenetic responses (MCyR) in 9 of 29 patients. MCyR rate = 31%). Hematologic and cytogenetic responses have occurred regardless of mutation status, or whether the mutation was in the P-loop, catalytic or activation region, with the exception of one patient who progressed with T315I. Responses are durable, and 33 of 36 patients remain on study for 1+ to 13+ months. BMS-354825 has been well tolerated. Three patients had grade 4 thrombocytopenia and 2 patients had grade 4 neutropenia, all of which were reversible and easily managed with dose modification. One patient developed a duodenal ulcer possibly related to BMS-354825. Mild QTc prolongation has been noted. Conclusions: BMS-345825 appears to be safe and effective therapy for patients with imatinib-resistant and imatinib-intolerant CML producing hematologic and cytogenetic responses. The phase I study continues to accrue patients to determine the maximally tolerated dose. No significant financial relationships to disclose.