Does the frequency of molecular monitoring after tyrosine kinase inhibitor discontinuation affect outcomes of patients with chronic myeloid leukemia?

BACKGROUND: To the authors' knowledge, the optimal frequency of monitoring after tyrosine kinase inhibitor (TKI) discontinuation in patients with chronic myeloid leukemia (CML) has not been established. Data regarding the discontinuation of second-generation TKIs used in first-line treatment or after the failure of first-line treatment with TKIs are limited. Herein, the authors report real-world experience with "reduced frequency" molecular monitoring in patients with CML in all phases who discontinued treatment with imatinib, dasatinib, or bosutinib. METHODS: The records of patients who discontinued TKIs were reviewed. Patients who discontinued TKIs were monitored prospectively on an intended schedule of monthly blood quantitative reverse transcriptase-polymerase chain reaction for BCR-ABL1 for 3 months, quarterly for 12 months, and every 6 months thereafter until loss of major molecular response (MMR). After loss of MMR, the TKI that previously was discontinued was reinitiated. RESULTS: Between January 2010 and September 2015, a total of 24 patients in chronic (21 patients), accelerated (2 patients), and lymphoid blast (1 patient) phase discontinued imatinib (16 patients), dasatinib (5 patients), or bosutinib (3 patients) used in the front-line treatment or beyond. Blood quantitative reverse transcriptase-polymerase chain reaction for BCR-ABL1 was performed 1.3 ± 0.7 times within the first 3 months (24 patients) and 2.7 ± 1.4 times in the following 12 months (18 patients). With a median follow-up of 36.5 months (range, 3.2-67.4 months), the probabilities of treatment-free remission at 1 year and 2 years were 65.7% (95% confidence interval, 55.8%-75.6%) and 59.7% (95% confidence interval, 49.1%-70.3%), respectively. Loss of MMR was observed in 9 patients at a median of 2.8 months (range, 1.8-14.2 months) after discontinuation of TKIs. CONCLUSIONS: With the limitations of a small sample size, the results of the current study demonstrate that less frequent monitoring of BCR-ABL1 does not appear to affect outcomes, and that discontinuation of TKIs used as first-line treatment or beyond after resistance or intolerance to first-line treatment appears feasible. Cancer 2017;123:2482-88. © 2017 American Cancer Society.

Does FLT3 mutation impact survival after hematopoietic stem cell transplantation for acute myeloid leukemia? A Center for International Blood and Marrow Transplant Research (CIBMTR) analysis.

BACKGROUND: Patients with FMS like tyrosine kinase 3 (FLT3)-mutated acute myeloid leukemia (AML) have a poor prognosis and are referred for early allogeneic hematopoietic stem cell transplantation (HCT). METHODS: Data from the Center for International Blood and Marrow Transplant Research (CIBMTR) were used to evaluate 511 adult patients with de novo AML who underwent HCT during 2008 through 2011 to determine whether FLT3 mutations had an impact on HCT outcomes. RESULTS: In total, 158 patients (31%) had FLT3 mutations. Univariate and multivariate analyses revealed an increased risk of relapse at 3 years in the FLT3 mutated group compared with the wild-type (WT) group (38% [95% confidence interval (CI), 30%-45%] vs 28% [95% CI, 24%-33%]; P = .04; relative risk, 1.60 [95% CI, 1.15-2.22]; P = .0048). However, FLT3 mutation status was not significantly associated with nonrelapse mortality, leukemia-free survival, or overall survival. Although more patients in the FLT3 mutated group died from relapsed primary disease compared with those in the WT group (60% vs 46%), the 3-year overall survival rate was comparable for the 2 groups (mutated group: 49%; 95% CI, 40%-57%; WT group: 55%, 95% CI, 50%-60%; P = .20). CONCLUSIONS: The current data indicate that FLT3 mutation status did not adversely impact overall survival after HCT, and about 50% of patients with this mutation who underwent HCT were long-term survivors. Cancer 2016;122:3005-3014. © 2016 American Cancer Society.

Predicting early blast transformation in chronic-phase chronic myeloid leukemia: is immunophenotyping the missing link?

BACKGROUND: Flow cytometry (FC) is a commonly requested test in the workup of leukocytosis in community practices. The role of FC in chronic-phase chronic myeloid leukemia (CP-CML) is unknown. We hypothesized that finding aberrant cells with FC in CP-CML may predict early blast-phase (BP) transformation. METHODS: Results for FC performed at the time of diagnosis for adult and pediatric patients with CP-CML who were referred to our institution were reviewed, and they were correlated with outcomes. RESULTS: FC was performed at the time of diagnosis for 110 of 233 patients (47%) with CP-CML. Aberrant populations, representing a median of 2% (range, 0.3%-15%), were detected with FC in 30% of patients (33 of 110): 2 of these 33 patients expressed lymphoid markers, and 31 expressed aberrant myeloid markers. Patients received imatinib (85%), dasatinib (12%), or nilotinib (3%) as their first-line treatment. With a median follow-up of 43 months (range, 2-113 months), chronic myeloid leukemia transformed to BP in 5 of the 33 patients. The 2 patients with lymphoid markers and the 3 of 31 patients with aberrant myeloid markers experienced a transformation to lymphoid BP at a median of 11 months (range, 4-72 months) after the initiation of tyrosine kinase inhibitor therapy. Although both cases with detectable lymphoid markers rapidly progressed to lymphoid BP, the positive predictive value of BP transformation by the detection of myeloid aberrant cells with FC was only 10% (3 of 31). CONCLUSIONS: In contrast to aberrant myeloid markers, the detection of lymphoid markers by FC at the time of the diagnosis of CP-CML appears to be associated with early progression to lymphoid BP.

Phase 1 dose escalation trial of ilorasertib, a dual Aurora/VEGF receptor kinase inhibitor, in patients with hematologic malignancies.

BACKGROUND: Ilorasertib (ABT-348) is a novel inhibitor of Aurora kinase, vascular endothelial growth factor (VEGF) and platelet-derived growth factor receptors, and the Src families of tyrosine kinases. Ilorasertib alone or in combination with azacitidine demonstrated activity in preclinical models in various hematological malignancies, indicating that pan-Aurora kinase and multiple kinase inhibition may have preferential antileukemic activity. This phase 1 trial determined the safety, pharmacokinetics, and preliminary antitumor activity of ilorasertib alone or combined with azacitidine in advanced hematologic malignancies. PATIENTS AND METHODS: Fifty-two patients (median age, 67 years; 35 % with >4 prior regimens) with acute myelogenous leukaemia (AML; n = 38), myelodysplastic syndrome (n = 12), or chronic myelomonocytic leukaemia (n = 2) received 3 or 6 doses of ilorasertib per 28-day cycle and were assigned to arm A (once-weekly oral), B (twice-weekly oral), C (once-weekly oral plus azacitidine), or D (once-weekly intravenous) treatment. RESULTS: Maximum tolerated doses were not determined; the recommended phase 2 oral monotherapy doses were 540 mg once weekly and 480 mg twice weekly. The most common grade 3/4 adverse events were hypertension (28.8 %), hypokalemia (15.4 %), anemia (13.5 %), and hypophosphatemia (11.5 %). Oral ilorasertib pharmacokinetics appeared dose proportional, with a 15-hour half-life and no interaction with azacitidine. Ilorasertib inhibited biomarkers for Aurora kinase and VEGF receptors, and demonstrated clinical responses in 3 AML patients. CONCLUSIONS: Ilorasertib exhibited acceptable safety and pharmacokinetics at or below the recommended phase 2 dose, displayed evidence of dual Aurora kinase and VEGF receptor kinase inhibition, and activity in AML.

FGFR3 activates RSK2 to mediate hematopoietic transformation through tyrosine phosphorylation of RSK2 and activation of the MEK/ERK pathway.

To better understand the signaling properties of oncogenic FGFR3, we performed phospho-proteomics studies to identify potential downstream signaling effectors that are tyrosine phosphorylated in hematopoietic cells expressing constitutively activated leukemogenic FGFR3 mutants. We found that FGFR3 directly tyrosine phosphorylates the serine/threonine kinase p90RSK2 at Y529, which consequently regulates RSK2 activation by facilitating inactive ERK binding to RSK2 that is required for ERK-dependent phosphorylation and activation of RSK2. Moreover, inhibition of RSK2 by siRNA or a specific RSK inhibitor fmk effectively induced apoptosis in FGFR3-expressing human t(4;14)-positive myeloma cells. Our findings suggest that FGFR3 mediates hematopoietic transformation by activating RSK2 in a two-step fashion, promoting both the ERK-RSK2 interaction and subsequent phosphorylation of RSK2 by ERK.

Bosutinib treatment for Philadelphia chromosome-positive leukemias.

The SRC-ABL inhibitor bosutinib is one of the five tyrosine kinase inhibitors currently approved for the treatment of Philadelphia chromosome-positive leukemias. Bosutinib has shown activity against all phases of resistant chronic myeloid leukemia that do not harbor the T315I or V299L ABL kinase domain mutations. Bosutinib is overall well tolerated; transient diarrhea is the most common side effect. This article summarizes the pharmacokinetics, pharmacodynamics, safety and efficacy of bosutinib for the treatment of Philadelphia chromosome-positive leukemias.

Incidence and geographic distribution of adult acute leukemia in the state of Georgia.

OBJECTIVE: We investigated an apparent increase in acute lymphoblastic leukemia (ALL) referrals from northern Georgia to a tertiary care center located in Atlanta. METHODS: Cases reported to the Georgia Comprehensive Cancer Registry and the national Surveillance Epidemiology and End Results cancer registry between 1999 and 2008 were analyzed. Age-adjusted incidence rates were calculated for all of the counties and public health regions and were compared with national rates calculated using Surveillance Epidemiology and End Results 17 data. Cases of adult acute myeloid leukemia served as controls. RESULTS: Age-adjusted incidence rates of adult ALL (0.8/100,000) and acute myeloid leukemia (4.6/100,000) were comparable to the national rates (0.9 and 5.2, respectively). The age-adjusted incidence rate of ALL in northern Georgia was 1.1 (95% confidence interval 0.8-1.5) and was not affected by race. CONCLUSIONS: The observed increase in cases of ALL at our tertiary center results from a referral pattern rather than heterogeneous distribution of adult ALL across Georgia.

Targeting levels or oligomerization of nucleophosmin 1 induces differentiation and loss of survival of human AML cells with mutant NPM1.

Nucleophosmin 1 (NPM1) is an oligomeric, nucleolar phosphoprotein that functions as a molecular chaperone for both proteins and nucleic acids. NPM1 is mutated in approximately one-third of patients with AML. The mutant NPM1c+ contains a 4-base insert that results in extra C-terminal residues encoding a nuclear export signal, which causes NPM1c+ to be localized in the cytoplasm. Here, we determined the effects of targeting NPM1 in cultured and primary AML cells. Treatment with siRNA to NPM1 induced p53 and p21, decreased the percentage of cells in S-phase of the cell cycle, as well as induced differentiation of the AML OCI-AML3 cells that express both NPMc+ and unmutated NPM1. Notably, knockdown of NPM1 by shRNA abolished lethal AML phenotype induced by OCI-AML3 cells in NOD/SCID mice. Knockdown of NPM1 also sensitized OCI-AML3 to all-trans retinoic acid (ATRA) and cytarabine. Inhibition of NPM1 oligomerization by NSC348884 induced apoptosis and sensitized OCI-AML3 and primary AML cells expressing NPM1c+ to ATRA. This effect was significantly less in AML cells coexpressing FLT3-ITD, or in AML or normal CD34+ progenitor cells expressing wild-type NPM1. Thus, attenuating levels or oligomerization of NPM1 selectively induces apoptosis and sensitizes NPM1c+ expressing AML cells to treatment with ATRA and cytarabine.

A phase 1 dose-escalation study of ARRY-520, a kinesin spindle protein inhibitor, in patients with advanced myeloid leukemias.

BACKGROUND: ARRY-520 selectively inhibits the mitotic kinesin spindle protein (KSP), which leads to abnormal monopolar spindle formation and apoptosis. METHODS: A phase 1 trial was conducted to establish the safety and the maximum tolerated dose (MTD) of ARRY-520 given as a 1-hour infusion in either a single dose or on a day 1, 3, and 5 divided-dose schedule per cycle in patients with advanced or refractory myeloid leukemias. Additional objectives were to characterize pharmacokinetics, assess preliminary clinical activity, and explore biomarkers of KSP inhibition with ARRY-520. A total of 36 patients with acute myelogenous leukemia (n = 34) or myelodysplastic syndromes (n = 2) with a median age of 66 years (range, 21-88 years) were enrolled: 15 in the single-dose schedule (dose levels: 2.5, 3.75, 4.5, and 5.6 mg/m(2)) and 21 in the divided-dose schedule (dose levels: 0.8, 1.2, 1.5, and 1.8 mg/m(2)/day). RESULTS: The MTD was 4.5 mg/m(2) total dose per cycle for both dose schedules. Dose-limiting toxicities included mucositis, exfoliative rash, hand-foot syndrome, and hyperbilirubinemia. Grades 3 or 4 reversible drug-related myelosuppression were observed in 33 of 36 patients. Plasma pharmacokinetic analyses revealed low clearance of ARRY-520 (~3 L/hour), a volume of distribution of ~450 L, and a median terminal half-life of >90 hours. Monopolar spindles were observed in blood mononuclear cells, through use of 4',6-diamidino-2-phenylindole nucleic acid stain and antitubulin antibodies. CONCLUSIONS: On the basis of the relative lack of clinical activity, further development of ARRY-520 as an antileukemic agent was halted. (Clinicaltrials.gov identifier NCT00637052).

A phase 1 dose escalation study of bortezomib combined with rituximab, cyclophosphamide, doxorubicin, modified vincristine, and prednisone for untreated follicular lymphoma and other low-grade B-cell lymphomas.

BACKGROUND: Bortezomib has demonstrated efficacy in patients with relapsed B-cell non-Hodgkin lymphoma (NHL) both alone and in combination with other agents; however, limited data exist regarding its toxicity in combination with common frontline therapies for indolent NHL. A phase 1 study of bortezomib combined with rituximab, cyclophosphamide, doxorubicin, modified vincristine, and prednisone (R-CHOP) was conducted in patients with untreated follicular lymphoma (FL) and other indolent NHLs. METHODS: Nineteen patients, including 10 patients with FL, were enrolled. The median patient age was 59 years (range, 29-71 years). Seven patients had a FL International Prognostic Index score ≥3. R-CHOP with the vincristine dose capped at 1.5 mg was administered on a 21-day cycle for 6 to 8 cycles, and 1 of 3 dose levels of bortezomib (1.0 mg/m(2) [n = 1], 1.3 mg/m(2) [n = 6], or 1.6 mg/m(2) [n = 12]) was administered on days 1 and 8 of each cycle using a Bayesian algorithm for dose escalation. RESULTS: The maximum tolerated dose (MTD) of bortezomib with modified R-CHOP was reached at 1.6 mg/m(2). Dose-limiting toxicity was observed in 5 patients (1 patient at a bortezomib dose of 1.0 mg/m(2), 1 patient at a bortezomib dose of 1.3 mg/m(2), and 3 patients at a bortezomib dose of 1.6 mg/m(2)). Neuropathy occurred in 16 patients (84%), including 2 patients (11%) who experienced grade 3 sensory neuropathy. Grade 4 hematologic toxicity occurred in 4 patients. Of 19 evaluable patients, 100% responded, and the complete response rate was 68%. At a median follow-up of 32 months, the 3-year progression-free survival rate was 89.5%. CONCLUSIONS: Bortezomib combined with modified R-CHOP produced high response rates without substantial increases in toxicity. A phase 2 study of R-CHOP and bortezomib given at this established MTD is currently ongoing.

Potent, transient inhibition of BCR-ABL with dasatinib 100 mg daily achieves rapid and durable cytogenetic responses and high transformation-free survival rates in chronic phase chronic myeloid leukemia patients with resistance, suboptimal response or intolerance to imatinib.

BACKGROUND: Dasatinib 100 mg once daily achieves intermittent BCR-ABL kinase inhibition and is approved for chronic-phase chronic myeloid leukemia patients resistant or intolerant to imatinib. To better assess durability of response to and tolerability of dasatinib, data from a 2-year minimum follow-up for a dose-optimization study in chronic-phase chronic myeloid leukemia are reported here. DESIGN AND METHODS: In a phase 3 study, 670 chronic-phase chronic myeloid leukemia patients with resistance, intolerance, or suboptimal response to imatinib were randomized to dasatinib 100 mg once-daily, 50 mg twice-daily, 140 mg once-daily, or 70 mg twice-daily. RESULTS: Data from a 2-year minimum follow-up demonstrate that dasatinib 100 mg once daily achieves major cytogenetic response and complete cytogenetic response rates comparable to those in the other treatment arms, and reduces the frequency of key side effects. Comparable 2-year progression-free survival and overall survival rates were observed (80% and 91%, respectively, for 100 mg once daily, and 75%-76% and 88%-94%, respectively, in other arms). Complete cytogenetic responses were achieved rapidly, typically by 6 months. In patients treated with dasatinib 100 mg once daily for 6 months without complete cytogenetic response, the likelihood of achieving such a response by 2 years was 50% for patients who had achieved a partial cytogenetic response, and only 8% or less for patients with minor, minimal, or no cytogenetic response. Less than 3% of patients suffered disease transformation to accelerated or blast phase. CONCLUSIONS: Intermittent kinase inhibition can achieve rapid and durable responses, indistinguishable from those achieved with more continuous inhibition.

Ruxolitinib: a steroid sparing agent in chronic graft-versus-host disease.

Inhibition of the Janus-associated kinases (JAK) with ruxolitinib (RUX) reduces graft-versus-host disease (GVHD) in preclinical and clinical models. In total 19 allograft recipients with moderate/severe steroid-dependent chronic GVHD received RUX as ≥2nd line salvage. RUX was well tolerated, and led to complete/partial resolution of oral (92/7%), cutaneous (82/0%), hepatic (71/28%), gastro-intestinal (75/17%), musculoskeletal (33/67%), pulmonary (0/80%), scleroderma (0/75%), vaginal (0/75%), and ocular (0/100%) chronic GVHD. Overall 18 achieved partial response and 1 complete response according to NIH Consensus Criteria. Responses occurred early and were sustained which enabled discontinuation (68%) or reduction of steroids to physiologic doses (21%). We conclude that RUX is an effective steroid-sparing agent in chronic GVHD.

Chronic Myeloid Leukemia: What Every Practitioner Needs to Know in 2017.

The prognosis of chronic phase chronic myeloid leukemia (CML) has improved so that life expectancy for patients responding to tyrosine kinase inhibitors (TKIs) is now equivalent to age-matched controls. Attention should be paid to comorbidities that impact survival. The success of TKI therapy can be easily and reliably assessed at well-accepted time points using quantitative polymerase chain reaction (PCR) standardized to the international scale. Patient-reported outcome (PRO) tools are readily available for use in the clinic and provide complementary information on the tolerance of TKIs. Effectively managing adverse events of TKIs can improve compliance and quality of life. Discontinuation of TKIs is the next frontier in CML. In select patients with sustained deep molecular remission, a discontinuation of TKI is associated with a durable treatment-free remission in approximately 50%. Patient engagement in their discontinuation can be achieved through a provider multi-team coaching, is complementary to the available guidelines, and may provide an additional safety net so that these discontinuations remain safe when applied in general practices.

Omacetaxine Mepesuccinate for Chronic Myeloid Leukemia.

Omacetaxine mepesuccinate is approved by the Food and Drug Administration in the United States for the treatment of chronic myeloid leukemia in chronic or accelerated phase resistant to two or more tyrosine kinase inhibitors. This review summarizes the mode of action, pharmacokinetics, efficacy and safety of omacetaxine mepesuccinate. Omacetaxine mepesuccinate has activity in chronic myeloid leukemia, especially in the chronic phase, regardless of the presence of ABL1 kinase domain mutations. Omacetaxine mepesuccinate has distinct but manageable adverse events profile. Omacetaxine mepesuccinate is a treatment option for a subset of patients with refractory chronic myeloid leukemia.

Management of advanced-phase chronic myeloid leukemia.

The management of chronic myeloid leukemia (CML) in accelerated or blast phase (advanced phase) remains a significant challenge despite the introduction of very effective tyrosine kinase inhibitors (TKIs). The biology of advanced-phase CML is complex and engages several pathways that are not optimally targeted by TKIs. Allogeneic stem cell transplantation remains the only potentially curative therapy, but the effectiveness of this conventional approach is limited. New strategies are required to improve the outlook for these patients.

Bosutinib: a third generation tyrosine kinase inhibitor for the treatment of chronic myeloid leukemia.

Bosutinib is an oral tyrosine kinase inhibitor (TKI) with very potent dual inhibitory activity against SRC and abelson gene. Bosutinib was approved in 2012 for the treatment of resistant Philadelphia chromosome positive chronic myeloid leukemia (CML). Bosutinib is a very effective TKI against all phases of intolerant or resistant CML regardless of the presence or absence of an abelson gene domain mutation, except for cases with detectable T315I or V299L. Bosutinib is overall well tolerated and associated with a unique, but manageable toxicity profile. Factors that influence the prescribing pattern of this drug are complex and include physicians', and increasingly patients and families' preference, patients' comorbid conditions, schedule of administration, as well as financial factors. This paper provides an overview of CML, the TKI market, pharmacokinetics, pharmacodynamics, clinical efficacy, safety and tolerability of bosutinib.

Bosutinib in the treatment of patients with Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia: an overview.

Bosutinib is an orally bioavailable SRC/ABL tyrosine kinase inhibitor with activity against all phases of resistant chronic myeloid leukemia that do not express the T315I or V299L ABL kinase domain mutations. Bosutinib has a unique toxicity profile that is manageable. This paper provides an overview of bosutinib, covering pharmacodynamics and pharmacokinetic properties, results of treatment in newly diagnosed and previously treated chronic myeloid leukemia patients, as well as common side effects.

Venous access catheter-related thrombosis in patients with cancer.

Patients with cancer are at high risk for developing venous thromboembolism (VTE), and the presence of a central venous catheter (CVC) further increases this risk. CVC-related VTE has serious implications related to the loss of vascular access, development of pulmonary embolism, recurrent VTE, infections and post-thrombotic syndrome. The pathogenesis of CVC-related VTE is complex and multifactorial, with risk factors associated with the catheter, the vessel selected for insertion and the underlying cancer as well as the anti-cancer therapy. Clinical presentation of CVC-related VTEs is often non-specific, and ultrasonography is the most commonly used radiological diagnostic test. Management of CVC-related VTE in patients with cancer requires a balance between the need for venous access, the risk of VTE recurrence and the risk of bleeding from treatment-induced thrombocytopenia. Effective VTE prophylaxis methods have yet to be defined. Ongoing studies are evaluating the role of newer oral antithrombotic agents and alternative interventional strategies for the prevention and treatment of CVC-related VTE in patients with cancer.

Sensitivity and specificity of cerebrospinal fluid flow cytometry for the diagnosis of leukemic meningitis in acute lymphoblastic leukemia/lymphoma.

The presence of leukemic blasts detected by light microscopy in cerebrospinal fluid (CSF) establishes the diagnosis of leukemic meningitis in acute lymphoblastic leukemia/lymphoma (ALL). Flow cytometry immunophenotyping (FCI) is a very sensitive method that detects a minute number of aberrant cells, and is increasingly performed on CSF samples. We sought to determine the sensitivity and specificity of CSF FCI for the diagnosis of leukemic meningitis in ALL. Between November 2007 and August 2011, 800 CSF samples from 80 patients with ALL were available from diagnostic lumbar punctures (LPs; n = 80), follow-up LPs (n = 687) and at the time of relapse (n = 33). FCI was performed on 267 samples, and only identified aberrant cells in cytologically confirmed cases of leukemic meningitis. A blinded review of all cases with detectable CSF nucleated cells confirmed these findings. We conclude that CSF FCI has a 100% sensitivity and specificity for the detection of lymphoblasts. However, additional studies are needed to define the role this procedure plays in the diagnosis of leukemic meningitis.