PTCH1 expression at diagnosis predicts imatinib failure in chronic myeloid leukaemia patients in chronic phase

The tyrosine kinase inhibitor (TKI) imatinib has revolutionized the management of chronic myeloid leukaemia (CML). However, around 25% of patients fail to sustain an adequate response. We sought to identify gene-expression biomarkers that could be used to predict imatinib response. The expression of 29 genes, previously implicated in CML pathogenesis, were measured by TaqMan Low Density Array in 73 CML patient samples. Patients were divided into low and high expression for each gene and imatinib failure (IF), probability of achieving CCyR, progression free survival and CML related OS were compared by Kaplan-Meier and log-rank. Results were validated in a second cohort of 56 patients, with a further technical validation using custom gene-expression assays in a conventional RT-qPCR in a sub-cohort of 37 patients. Patients with low PTCH1 expression showed a worse clinical response for all variables in all cohorts. PTCH1 was the most significant predictor in the multivariate analysis compared with Sokal, age and EUTOS. PTCH1 expression assay showed the adequate sensitivity, specificity and predictive values to predict for IF. Given the different treatments available for CML, measuring PTCH1 expression at diagnosis may help establish who will benefit best from imatinib and who is better selected for second generation TKI.

Early administration of donor lymphocyte infusions upon molecular relapse after allogeneic hematopoietic stem cell transplantation for chronic myeloid leukemia: a study by the Chronic Malignancies Working Party of the EBMT

Patients with chronic myeloid leukemia relapsing after allogeneic hematopoietic stem cell transplantation may be treated by tyrosine kinase inhibitors and/or by donor lymphocyte infusions. The best strategies and timing of administration of lymphocytes are unclear. We analyzed 155 patients who relapsed after allogeneic stem cell transplantation with disease detectable only by molecular methods and who subsequently received lymphocytes. Transplants were performed in first chronic phase (n=125) or in advanced disease (n=29) from identical siblings (n=84) or unrelated donors (n=71) between 1986 and 2003. They received lymphocytes either during molecular relapse (n=85) or upon progression to more advanced disease (1993 to 2004). The median interval from relapse to lymphocyte infusion was 210 (0-1673) days. The median follow up after it was 46 (3-135) months. Overall survival was 76±4% at five years after lymphocyte infusions (89±8% with sibling donors and 63±13% with unrelated donors (P=0.003)). Survival was 69±14% when lymphocytes were given within six months of the detection of molecular relapse and 81±10% (P=0.061) when given later; 81±11% if given at molecular relapse versus 71±12% (P=0.26) with more advanced disease. In multivariate analysis survival was worse if the donor was unrelated (HR 2.54 (95% CI: 1.15-5.53), P=0.021) and better with lymphocyte infusions beyond six months from molecular relapse (HR 0.4 (95%CI: 0.19-0.84), P=0.018). These data confirm the remarkable efficacy of lymphocyte infusions for this disease. There appears to be no advantage from administering it early upon detection of molecular relapse in patients who received allogeneic stem cell transplantation for chronic myeloid leukemia.

Autologous haematopoietic stem cell mobilisation in multiple myeloma and lymphoma patients: a position statement from the European Group for Blood and Marrow Transplantation

Autologous haematopoietic SCT with PBSCs is regularly used to restore BM function in patients with multiple myeloma or lymphoma after myeloablative chemotherapy. Twenty-eight experts from the European Group for Blood and Marrow Transplantation developed a position statement on the best approaches to mobilising PBSCs and on possibilities of optimising graft yields in patients who mobilise poorly. Choosing the appropriate mobilisation regimen, based on patients' disease stage and condition, and optimising the apheresis protocol can improve mobilisation outcomes. Several factors may influence mobilisation outcomes, including older age, a more advanced disease stage, the type of prior chemotherapy (e.g., fludarabine or melphalan), prior irradiation or a higher number of prior treatment lines. The most robust predictive factor for poor PBSC collection is the CD34(+) cell count in PB before apheresis. Determination of the CD34(+) cell count in PB before apheresis helps to identify patients at risk of poor PBSC collection and allows pre-emptive intervention to rescue mobilisation in these patients. Such a proactive approach might help to overcome deficiencies in stem cell mobilisation and offers a rationale for the use of novel mobilisation agents.

Use of the quality management system "JACIE" and outcome after hematopoietic stem cell transplantation

Competent authorities, healthcare payers and hospitals devote increasing resources to quality management systems but scientific analyses searching for an impact of these systems on clinical outcome remain scarce. Earlier data indicated a stepwise improvement in outcome after allogeneic hematopoietic stem cell transplantation with each phase of the accreditation process for the quality management system "JACIE". We therefore tested the hypothesis that working towards and achieving "JACIE" accreditation would accelerate improvement in outcome over calendar time. Overall mortality of the entire cohort of 107,904 patients who had a transplant (41,623 allogeneic, 39%; 66,281 autologous, 61%) between 1999 and 2006 decreased over the 14-year observation period by a factor of 0.63 per 10 years (hazard ratio: 0.63; 0.58-0.69). Considering "JACIE"-accredited centers as those with programs having achieved accreditation by November 2012, at the latest, this improvement was significantly faster in "JACIE"-accredited centers than in non-accredited centers (approximately 5.3% per year for 49,459 patients versus approximately 3.5% per year for 58,445 patients, respectively; hazard ratio: 0.83; 0.71-0.97). As a result, relapse-free survival (hazard ratio 0.85; 0.75-0.95) and overall survival (hazard ratio 0.86; 0.76-0.98) were significantly higher at 72 months for those patients transplanted in the 162 "JACIE"-accredited centers. No significant effects were observed after autologous transplants (hazard ratio 1.06; 0.99-1.13). Hence, working towards implementation of a quality management system triggers a dynamic process associated with a steeper reduction in mortality over the years and a significantly improved survival after allogeneic stem cell transplantation. Our data support the use of a quality management system for complex medical procedures.

Preclinical and clinical efficacy of XPO1/CRM1 inhibition by the karyopherin inhibitor KPT-330 in Ph+ leukemias

As tyrosine kinase inhibitors (TKIs) fail to induce long-term response in blast crisis chronic myelogenous leukemia (CML-BC) and Philadelphia chromosome-positive (Ph(+)) acute lymphoblastic leukemia (ALL), novel therapies targeting leukemia-dysregulated pathways are necessary. Exportin-1 (XPO1), also known as chromosome maintenance protein 1, regulates cell growth and differentiation by controlling the nucleocytoplasmic trafficking of proteins and RNAs, some of which are aberrantly modulated in BCR-ABL1(+) leukemias. Using CD34(+) progenitors from CML, B-ALL, and healthy individuals, we found that XPO1 expression was markedly increased, mostly in a TKI-sensitive manner, in CML-BC and Ph(+) B-ALL. Notably, XPO1 was also elevated in Ph(-) B-ALL. Moreover, the clinically relevant XPO1 inhibitor KPT-330 strongly triggered apoptosis and impaired the clonogenic potential of leukemic, but not normal, CD34(+) progenitors, and increased survival of BCR-ABL1(+) mice, 50% of which remained alive and, mostly, became BCR-ABL1 negative. Moreover, KPT-330 compassionate use in a patient with TKI-resistant CML undergoing disease progression significantly reduced white blood cell count, blast cells, splenomegaly, lactate dehydrogenase levels, and bone pain. Mechanistically, KPT-330 altered the subcellular localization of leukemia-regulated factors including RNA-binding heterogeneous nuclear ribonucleoprotein A1 and the oncogene SET, thereby inducing reactivation of protein phosphatase 2A tumor suppressor and inhibition of BCR-ABL1 in CML-BC cells. Because XPO1 is important for leukemic cell survival, KPT-330 may represent an alternative therapy for TKI-refractory Ph(+) leukemias.

PP2A-activating drugs selectively eradicate TKI-resistant chronic myeloid leukemic stem cells

The success of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML) depends on the requirement for BCR-ABL1 kinase activity in CML progenitors. However, CML quiescent HSCs are TKI resistant and represent a BCR-ABL1 kinase-independent disease reservoir. Here we have shown that persistence of leukemic HSCs in BM requires inhibition of the tumor suppressor protein phosphatase 2A (PP2A) and expression--but not activity--of the BCR-ABL1 oncogene. Examination of HSCs from CML patients and healthy individuals revealed that PP2A activity was suppressed in CML compared with normal HSCs. TKI-resistant CML quiescent HSCs showed increased levels of BCR-ABL1, but very low kinase activity. BCR-ABL1 expression, but not kinase function, was required for recruitment of JAK2, activation of a JAK2/β-catenin survival/self-renewal pathway, and inhibition of PP2A. PP2A-activating drugs (PADs) markedly reduced survival and self-renewal of CML quiescent HSCs, but not normal quiescent HSCs, through BCR-ABL1 kinase-independent and PP2A-mediated inhibition of JAK2 and β-catenin. This led to suppression of human leukemic, but not normal, HSC/progenitor survival in BM xenografts and interference with long-term maintenance of BCR-ABL1-positive HSCs in serial transplantation assays. Targeting the JAK2/PP2A/β-catenin network in quiescent HSCs with PADs (e.g., FTY720) has the potential to treat TKI-refractory CML and relieve lifelong patient dependence on TKIs.

Syngeneic transplantation in aplastic anemia: pre-transplant conditioning and peripheral blood are associated with improved engraftment: an observational study on behalf of the Severe Aplastic Anemia and Pediatric Diseases Working Parties of the European Group for Blood and Marrow Transplantation

Aplastic anemia is usually treated with immunosuppression or allogeneic transplant, depending on patient and disease characteristics. Syngeneic transplant offers a rare treatment opportunity with minimal transplant-related mortality, and offers an insight into disease mechanisms. We present here a retrospective analysis of all syngeneic transplants for aplastic anemia reported to the European Group for Blood and Marrow Transplantation. Between 1976 and 2009, 88 patients received 113 transplants. Most transplants (n=85) were preceded by a conditioning regimen, 22 of these including anti-thymocyte globulin. About half of transplants with data available (39 of 86) were followed by posttransplant immunosuppression. Graft source was bone marrow in the majority of cases (n=77). Transplant practice changed over time with more transplants with conditioning and anti-thymocyte globulin as well as peripheral blood stem cells performed in later years. Ten year overall survival was 93% with 5 transplant-related deaths. Graft failure occurred in 32% of transplants. Risk of graft failure was significantly increased in transplants without conditioning, and with bone marrow as graft source. Lack of posttransplant immunosuppression also showed a trend towards increased risk of graft failure, while anti-thymocyte globulin did not have an influence. In summary, syngeneic transplant is associated with a significant risk of graft failure when no conditioning is given, but has an excellent long-term outcome. Furthermore, our comparatively large series enables us to recommend the use of pre-transplant conditioning rather than not and possibly to prefer peripheral blood as a stem cell source.

Analysis of the cardiovascular risk profile of Ph+ leukemia patients treated with ponatinib

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Background: Coronary artery disease (CAD), peripheral arterial occlusive disease and cerebrovascular disease have been observed in pts treated with BCR-ABL tyrosine kinase inhibitors (TKIs). While uncommon, these events can be serious complications of BCR-ABL TKI therapy. Methods: The cardiovascular (CV) profile of ponatinib (45 mg/day) was evaluated in 449 pts with chronic myeloid leukemia (CML) or Ph+ acute lymphoblastic leukemia (Ph+ ALL) resistant or intolerant to prior TKIs in the phase 2 PACE trial. At analysis (23 July 2012), median follow-up was 12 (0.1-21) mos. Myocardial ischemic events including myocardial infarction (MI), CAD, and angina were analyzed. Results: Myocardial ischemic serious adverse events (SAEs) (14 MI, 5 CAD, 2 angina) were reported in 21/449 pts (5%). 10 of these 21 pts had active cardiac disease at entry characterized by prior MI (4 pts), coronary revascularization (4 pts), or documented CAD; 5 had MI reported on study. 5/21 pts had other cardiac disease at entry (eg, valvular or pericardial disease); 5 had MI on study. Thus, 10/14 MIs occurred in 15 pts with known cardiac disease. 6/21 pts had no history of cardiac disease, but 5/6 had ≥1 CAD risk factor; 4 MIs occurred in these pts, all had risk factors. Of 21 pts with myocardial ischemic SAEs (13 CP-CML, 6 AP-CML, 2 BP-CML/Ph+ALL), mean age was 67 (42-87), and median duration since diagnosis was 12 (1-20) yrs. They were heavily pretreated (67% TKI use ≥5 yrs) with multiple CAD risk factors at entry (71% ischemia, 57% hypertension, 38% hypercholesterolemia, 33% diabetes [62% BMI >25]); 81% had ≥2 risk factors, 95% had ≥1. Median time to onset and duration of SAE was 160 (9E402) and 7 (1E98) days, respectively. At analysis, 18/21 pts had the SAE reported as resolved (managed by dose interruption [50%] or no dose change [33%]), and 13/21 pts remained on study. Response rates for the subset of 21 pts with cardiac SAEs were major cytogenetic response 77% in CP-CML; major hematologic response 67% in AP-CML. Conclusions: In this uncontrolled study in heavily pretreated pts, these CV SAEs occurred mostly in pts with preexisting cardiac disease, and were primarily managed with satisfactory outcomes. Pts with preexisting CV co-morbidities should be monitored. Clinical trial information: NCT01207440.

Fast-mode duplex qPCR for BCR-ABL1 molecular monitoring: innovation, automation, and harmonization

Reverse transcription quantitative polymerase chain reaction (RTqPCR)is currently the most sensitive tool available for the routine monitoring of disease level in patients undergoing treatment for BCRABL1 associated malignancies. Considerable effort has been invested at both the local and international levels to standardise the methodology and reporting criteria used to assess this critical metric. In an effort to accommodate the demands of increasing sample throughput and greater standardization, we adapted the current best-practice guidelines to encompass automation platforms and improved multiplex RT-qPCR technology.

PACE: A pivotal phase II trial of ponatinib in patients with CML and Ph+ALL resistant or intolerant to dasatinib or nilotinib, or with the T315I mutation

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Background: Ponatinib is a potent, oral, pan-BCR-ABL inhibitor active against the native enzyme and all tested resistant mutants, including the uniformly resistant T315I mutation. Methods: The PACE (Ponatinib Ph+ALL and CML Evaluation) trial started Sept 2010. Pts with refractory CML (CP, AP or BP) or Ph+ALL resistant or intolerant (R/I) to dasatinib or nilotinib or with T315I received 45 mg ponatinib once daily. The trial is ongoing; enrollment completed Sept 2011. Data as of 17 Jan 2012 are reported. Results: 449 pts were enrolled, 5 of whom were ineligible (post-imatinib, non-T315I) but treated. Median age was 59 (18-94) yrs; 53% male. Diagnoses were: 271 CP-CML (R/I=207; T315I=64); 79 AP-CML (R/I=60; T315I=19); 94 BP/ALL (R/I=48; T315I=46). Median time from diagnosis to ponatinib was 6 yrs. Prior TKIs included imatinib (96%), dasatinib (85%), nilotinib (66%), bosutinib (7%); 94% failed ≥2 prior TKIs, 59% failed ≥3 prior TKIs. 83% had a history of resistance to dasatinib or nilotinib; 12% were purely intolerant. In CP, best response to most recent dasatinib or nilotinib was MCyR 25%. Frequent mutations confirmed at entry: 29% T315I, 8% F317L, 4% E255K, 4 % F359V, 3% G250E. Median follow-up was 6.6 months. Response rates are presented in the table. Overall, 64% remained on therapy (77% CP). Most frequent reasons for discontinuation were progression (12%) and AE (10%). Most common drug‑related AEs were thrombocytopenia (33%), rash (33%), dry skin (26%). Conclusions: Ponatinib has substantial activity in heavily pretreated pts and those with refractory T315I. Response rates continue to improve with longer follow-up. Multivariate analyses of predictors of outcome will be presented. [Table: see text]

BCR-ABL1 kinase domain mutations: methodology and clinical evaluation

The introduction of tyrosine kinase inhibitors (TKIs), starting with imatinib and followed by second and third generation TKIs, has significantly changed the clinical management of patients with chronic myeloid leukemia (CML). Despite their unprecedented clinical success, a proportion of patients fail to achieve complete cytogenetic remission by 12 months of treatment (primary resistance) while others experience progressive resistance after an initial response (secondary resistance). BCR-ABL1 kinase domain (KD) mutations have been detected in a proportion of patients at the time of treatment failure, and therefore their identification and monitoring plays an important role in therapeutic decisions particularly when switching TKIs. When monitoring KD mutations in a clinical laboratory, the choice of method should take into account turnaround time, cost, sensitivity, specificity, and ability to accurately quantify the size of the mutant clone. In this article, we describe in a "manual" style the methods most widely used in our laboratory to monitor KD mutations in patients with CML including direct sequencing, D-HPLC, and pyrosequencing. Advantages, disadvantages, interpretation of results, and their clinical applications are reviewed for each method.