Despite being considered as good prognostic acute myelogenous leukemia (AML), the long-term survival rate in core binding factor AML leaves room for substantial improvement. We discuss treatments that have improved outcome in this group of patients with AML and ongoing/future strategies that might contribute toward incremental gains.
Despite being considered as good prognostic acute myelogenous leukemia (AML), the long-term survival rate in core binding factor (CBF) AML leaves room for substantial improvement.
Materials and Methods
We reviewed relevant English language literature related to treatment of CBF AML available in PubMed. Review also included meeting abstracts.
Multicycle high dose cytarabine in consolidation improves remission duration but larger groups report overall survival in the range of 40% to 50% at 5 years or longer.
Concerted effort is needed toward improving outcomes in CBF AML through clinical trials and risk-adapted approach.
Chemotherapy; High-dose cytarabine; Inversion (16); Response; Translocation (8:21)
The outcome of patients with myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) post clofarabine is unknown.
We reviewed 109 patients with MDS or CMML with a median age of 67 years, treated with a clofarabine-based chemotherapy as frontline (n = 38) or salvage (n = 71) therapy. A total of 58 (53%) patients received salvage therapy after clofarabine failure: 13 allogeneic stem cell transplant (ASCT), 18 high-dose cytarabine-containing regimen, 10 hypomethylating agents and 17 investigational treatments.
Eight patients achieved complete remission (CR) and three had stable disease for an overall response rate of 19%. With a median follow-up of 3 months from clofarabine failure, 12 patients (11%) remained alive, 5 remain in CR, 4 of them after ASCT. The median overall survival post clofarabine failure was 4 months with a 1-year survival rate of 23%.
This outcome is predictable, with patients with high-risk disease at the time of clofarabine failure having the worse survival. To date, patients with MDS continue to have a short survival after failure of all available therapies. Ultimately, patients who are candidates for additional treatments should be offered novel approaches. In conclusion, the outcome of patients with MDS and CMML post clofarabine failure is poor. The pattern is similar to patients with MDS post hypomethylating agent failure and predictable using University of Texas M. D. Anderson Cancer Center global scoring system.
chronic myelomonocytic leukemia; clofarabine; myelodysplastic syndrome
Imatinib and other BCR-ABL1 inhibitors are effective therapies for chronic myeloid leukemia (CML), but these inhibitors target additional kinases including KIT, raising the question of whether off-target effects contribute to clinical efficacy. Based on its involvement in CML pathogenesis, we hypothesized that KIT may govern responses of CML cells to imatinib. To test this, we assessed the growth of primary CML progenitor cells under conditions of sole BCR-ABL1, sole KIT and dual BCR-ABL1/KIT inhibition. Sole BCR-ABL1 inhibition suppressed mature CML progenitor cells, but these effects were largely abolished by stem cell factor (SCF) and maximal suppression required dual BCR-ABL1/KIT inhibition. In contrast, KIT inhibition did not add to the effects of BCR-ABL1 inhibition in primitive progenitors, represented by CD34+38− cells. Long term culture-initiating cell (LTC-IC) assays on murine stroma revealed profound depletion of primitive CML cells by sole BCR-ABL1 inhibition despite the presence of SCF, suggesting primitive CML cells are unable to use SCF as a survival factor upon BCR-ABL1 inhibition. In CD34+38+ cells, SCF strongly induced pAKTS473 in a phosphatidylinositol 3′ kinase (PI3K)-dependent manner, which was further enhanced by inhibition of BCR-ABL1 and associated with increased colony survival. In contrast, pAKTS473 levels remained low in CD34+38− cells cultured under the same conditions. Consistent with reduced response to SCF, KIT surface expression was significantly lower on CD34+38− compared to CD34+38+ CML cells, suggesting a possible mechanism for the differential effects of SCF on mature and primitive CML progenitor cells.
Anemia is an expected consequence of intensive chemotherapy regimens administered to acute leukemia patients. This study was designed to determine if epoetin alfa would decrease the number of transfusion events and units of packed red blood cells (PRBCs) transfused, and secondarily, to study its effects on quality of life (QOL) and complete remission (CR) rates.
Patients and Methods
Patients with acute lymphoblastic leukemia (ALL), lymphoblastic lymphoma (LL), or Burkitt’s lymphoma (BL) receiving frontline myelosuppressive chemotherapy were randomized to receive epoetin alfa or no epoetin during the first 6 cycles of their planned chemotherapy. QOL was assessed by Edmonton Symptom Assessment Scale (ESAS) and FACT-Anemia questionnaires.
Fifty five patients were randomized to epoetin alfa and 54 to no epoetin. Transfusion data was available in 79 of the 81 (98%) evaluable patients who completed the treatment/observation period. The trial was stopped early due to poor accrual before the target of 123 evaluable patients was met. A mean of 10.6 units of PRBCs over 5 months were administered to those receiving epoetin alfa compared to 13 units for those who did not (p=0.04). There was no significant difference in QOL as assessed by FACT-Anemia or ESAS. The CR rate and 3-year CR duration were not adversely affected by use of epoetin alfa.
Epoetin alfa decreases the number of PRBC transfusions and does not appear to negatively impact remission duration. No difference in QOL was observed.
Anemia; epoetin; leukemia
A cross-sectional survey of board certified hematologists/oncologists was conducted to describe current chronic myeloid leukemia (CML) practice patterns and compare these self-reported practices with the clinical guidelines. Overall, the reported practice patterns regarding CML treatment were in accordance with guidelines; however, decisions also appear to be based on the attitudes, beliefs, and personal experience of the responding physicians.
A previous survey of physician self-reported practice patterns in the management of CML was conducted in 2005. The National Comprehensive Cancer Network and European LeukemiaNet guidelines now include nilotinib and dasatinib in their treatment algorithms for CML. To assess these new guidelines, a cross-sectional survey of US hematologists and/or oncologists was conducted in December 2010 through an online survey.
Materials and Methods
The survey had 43 questions consisting of items updated from the 2005 survey to reflect changes in clinical practice, tyrosine kinase inhibitor therapy, and current guidelines.
Analysis of the responses from 507 board certified medical oncologists/hematologists suggests that the use of imatinib 400 mg as an initial treatment option had decreased from 62% in 2005 to 52% in the 2010 survey. Currently, nearly 40% of physicians would choose either nilotinib or dasatinib as first-line treatment. From the surveyed physicians, achievement of at least a major molecular response (MMR) is the predominant treatment goal in chronic phase CML.
This survey emphasizes the need for continued updates and education regarding optimal therapy, monitoring practices, and therapeutic end points in CML.
CML; Guidelines; Practice patterns; Survey; Tyrosine kinase inhibitors
Allogeneic hematopoietic stem cell transplantation (HSCT) is curative treatment, albeit in a minority of patients with accelerated (AP) or blast phase (BP) chronic myeloid leukemia (CML). Imatinib (IM) has transient but significant activity in advanced phases of CML, which may permit early allografting for responding patients. To identify prognostic factors in allograft recipients previously treated with IM, we analyzed 449 allogeneic HSCT performed between 1999–2004 in advanced phase CML using data reported to the Center for International Blood and Marrow Transplant Research. CML patients in second chronic phase (CP2, n=184), AP (n=185), and BP (n=80) received HLA-identical sibling (27%), related (3%), or matched or mismatched unrelated donor (70%), peripheral blood (47%) or bone marrow (53%) HSCT after myeloablative (78%) or non-myeloablative (22%) conditioning. 52% in CP2, 49% in AP, and 46% in BP received IM pre-HSCT. Disease-free survival was 35–40% for CP2, 26–27% for AP and 8–11% for BP. Cumulative incidence of acute and chronic GVHD and TRM were not affected by stages of CML or pre-HSCT IM exposure. Multivariate analyses showed that conventional prognostic indicators remain the strongest determinants of transplant outcomes. In conclusion, there are no new prognostic indicators of outcomes of allogeneic HSCT for advanced phase CML in the IM era.
Imatinib; allogeneic transplantation; chronic myeloid leukemia; accelerated phase; blast phase; outcomes
Splenectomy may be an effective therapeutic option for treating massive splenomegaly in patients with myeloproliferative neoplasms (MPNs). There is still limited data on its short- and long-term benefits and risks.
Efficacy and short-term complications were analyzed in 94 patients with different MPNs who underwent splenectomy at MD Anderson. The long-term impact of splenectomy on overall survival (OS) and transformation free survival (TFS) was evaluated in 461 patients with myelofibrosis (MF) seen at MD Anderson including 50 who underwent splenectomy during disease evolution.
Splenectomy improved anemia and thrombocytopenia in 47% and 66% of patients, respectively. Most common complications were leukocytosis (76%), thrombocytosis (43%), and venous thromboembolism (16%). Post-operative mortality was 5%. Among patients with MF, splenectomy during disease evolution was associated with decreased OS (Hazard Ratio [HR] =2.17, p<0.0001) and TFS (HR=2.17, p<0.0001). This effect was independent of the Dynamic International Prognostic Scoring System.
Splenectomy is a possible therapeutic option for patients with MF and other MPNs, and its greatest benefits are related to improvement in spleen pain and discomfort, anemia and thrombocytopenia. However, in patients with MF it appears to be associated with increased mortality.
Myelofibrosis; Myeloproliferative Neoplasms; Splenectomy; Survival; Acute Myeloid Leukemia
We evaluated the efficacy and safety of the combination of twice-daily fludarabine and cytarabine (BIDFA) in patients with refractory/relapsed acute myeloid leukemia (AML), high-risk myelodysplastic syndromes (MDS), and chronic myeloid leukemia in myeloid blast phase (CML-BP). One hundred seven patients were enrolled. Overall, 27 (26%) patients responded with a complete remission (CR) rate of 21% and CR without platelet recovery (CRp) of 5%. The overall 4-week mortality rate was 9%. In conclusion, BIDFA is active and safe in heavily pretreated patients with myeloid malignancies.
The purpose of this study was to evaluate the efficacy and safety of the combination of twice-daily fludarabine and cytarabine (BIDFA) in patients with refractory/relapsed acute myeloid leukemia (AML), high-risk myelodysplastic syndromes (MDS), and chronic myeloid leukemia in myeloid blast phase (CML-BP).
Patients and Methods
One hundred seven patients with refractory/relapsed AML, intermediate and high-risk MDS, and CML-BP, with a performance status of 3 or less and normal organ function were treated. Patients received fludarabine 15 mg/m2 intravenously (IV) every 12 hours on days 1 to 5 and cytarabine 0.5 g/m2 IV over 2 hours every 12 hours on days 1 to 5. Gemtuzumab ozogamicin (GO) was administered at 3 mg/m2 IV on day 1 in the first 59 patients. Patients with CML-BP were allowed to receive concomitant tyrosine kinase inhibitors.
Overall, 27 (26%) patients responded with a complete remission (CR) rate of 21% and CR without platelet recovery of 5%. The overall 4-week mortality rate was 9%. The CR rates for patients with relapsed AML with first CR duration greater than or equal to 12 months, relapsed AML with first CR duration less than 12 months, and refractory/relapsed AML beyond first salvage were 56%, 26%, and 11%, respectively. With a median follow-up of 7 months, the 6-month event-free survival, overall survival, and complete remission CR duration rates were 18%, 35%, and 70%, respectively.
BIDFA is active with an overall response rate of 26% in a heavily pretreated population. This combination is safe with a low 4-week mortality rate of 9%.
Acute myeloid leukemia; Efficacy; Refractory; Safety
Nontuberculous mycobacteria (NTM) are environmental opportunistic pathogens found in natural and human-engineered waters, including drinking water distribution systems and household plumbing. This pilot study examined the frequency of occurrence of NTM in household potable water samples in Mexico City. Potable water samples were collected from the “main house faucet” and kitchen faucet. The presence of aerobic-mesophilic bacteria (AMB), total coliforms (TC), fecal coliforms (FC) and NTM species were determined. Mycobacteria species were identified by PCR restriction enzyme pattern analysis (PRA) of the 65-kDa heat shock protein gene (hsp65) and sequencing of the hypervariable region 2 (V2) of the 16S rRNA gene and of the rpoB gene.
AMB (<100 CFU/ml) were present in 118 out of 120 samples; only two samples were outside guidelines ranges (>100 CFU/ml). TC and FC were detected in four and one samples, respectively. NTM species were recovered from 16% samples (19/120) and included M. mucogenicum (nine), M. porcinum (three), M. avium (three), M. gordonae (one), M. cosmeticum (one), M. fortuitum (one), and Mycobacterium sp (one). All household water samples that contained NTM complied with the standards required to grade the water as “good quality” potable water.
Household potable water may be a potential source of NTM infection in Mexico City.
Household water microbiological quality; Mycobacteria in potable water; Nontuberculous mycobacteria (NTM); Mycobacterium mucogenicum
Little information exists regarding the prevalence and natural history of pericardial disease in patients with leukemia. Recently, it has been reported that the use of histone deacytelase inhibitors (HDACi) is associated with an increased incidence of pericardial effusions (PEfs). To study the characteristics and treatment relationships of PEfs in patients with leukemia, we retrospectively analyzed a cohort of patients with leukemia evaluated at a single center.
We reviewed 2592 patients with acute myeloid leukemia (AML, N= 1282, 49%), acute lymphocytic leukemia (ALL, N= 336, 13%), or myelodysplastic syndrome (MDS, N=974, 38%), who were evaluated from 8/2003 to 7/2008. Electronic medical records were reviewed to select patients that had underwent at least one echocardiographic evaluation. Data regarding diagnosis, timing, effusion size, survival, and prior therapy was collected in the patients that had echocardiographic evidence of PEfs.
PEfs were detected in 325 (20%) of the patients who had echocardiograms: 21% in AML, 23% in ALL, and 18% in MDS patients. Only a small portion of PEfs were detected prior to the initiation of therapy: 26% in AML, 25% ALL, and 15% in MDS. Most PEfs were of minimal size (70%) overall. No significant differences in effusion characteristics, including severity, were observed among different types of therapies. The presence of PEfs had no impact on the survival of patients evaluated.
PEfs are relatively common in patients with leukemia and do not appear to be related to specific types of therapy or to survival.
leukemia; pericardial effusions; histone deacetylase inhibitors
Activating mutations in RAS are frequently present in patients with AML, but their overall prognostic impact is not clear.
A retrospective analysis was done to establish the clinical characteristics of patients with RASmut AML, to analyze their outcome by therapy, and to describe the proteomic profile of RASmut relative to RASWT AML.
Out of 609 patients with newly diagnosed AML, 11% had mutated RAS. Compared with RASWT, patients with RASmut AML were younger (median 54 vs. 63 yrs, p=0.001), had a higher WBC (16 vs. 4.2, p<0.001) and marrow blast percentage (56% vs. 42%, p=0.01) at diagnosis, and less likely to have an antecedent hematologic disorder (36% vs. 50%, p=0.03). The inv(16) karyotype was overrepresented in patients with RASmut and -5 and/or -7 karyotype was underrepresented. RAS mutation had no prognostic impact on OS or DFS overall or within cytogenetic subgroups. There was a suggestion that patients with RASmut benefited from AraC-based therapy. Proteomic analysis revealed simultaneous upregulation of the RAS-Raf-MAP kinase and PI3K signaling pathways in patients with RASmut.
RAS mutations in AML may delineate a subset of patients who benefit from AraC-based therapy and who may be amenable to treatment with inhibitors of RAS and PI3K signaling pathways.
AML; RAS; signal transduction
Chronic myeloid leukemia (CML) is a clonal stem cell malignancy whose pathogenesis is driven by constitutive activation of the breakpoint cluster region–v-abl Abelson murine leukemia viral oncogene homolog 1 (BCR-ABL1) kinase. Although BCR-ABL1 activation is present in all patients with CML, patients can present in 3 different phases characterized by an increasingly worse prognosis and diminished responsiveness to tyrosine kinase inhibitors: chronic phase, accelerated phase, or blastic phase. The biologic basis for progression from chronic phase to blastic phase and for regulating the homeostasis of tyrosine kinase inhibitor-resistant CML stem cells is not entirely understood.
To shed some light into these aspects of CML biology, the authors used reverse phase protein arrays probed with 112 individual monoclonal antibodies to compare protein expression patterns in 40 samples of leukemia-enriched fractions from patients with CML (25 in chronic phase, 5 in accelerated phase, and 10 in phase).
An analysis of variance (significance cutoff, P < .01) unveiled a set of proteins that were overexpressed in blastic phase, including heat-shock protein 90 (hsp90); retinoblastoma (Rb); apoptosis-inducing factor (AIF); serine/threonine-protein phosphatase 2A (PP2A); B-cell leukemia 2 (Bcl-2); X-linked inhibitor of apoptosis protein (Xiap); human homolog of Drosophila Mad (mothers against decapenta-plegic) and related Caenorhabditis elegans gene Sma, family member 1 (Smad1); single-stranded DNA binding protein 2 alpha (SSBP2α); poly(adenosine diphosphate-ribose) polymerase (PARP); GRB2-associated binding protein 2 (Gab2); and tripartite motif containing 24 (Trim24). It is noteworthy that several of these proteins also were overexpressed in the CD34-positive compartment, which putatively contains the CML stem cell population.
The results from this study indicated that reverse phase protein array analysis can unveil differentially expressed proteins in advanced phase CML that can be exploited therapeutically with targeted approaches.
chronic myeloid leukemia; protein expression; reverse phase protein array; signature; blastic phase; chronic phase; proteomics
Acute myeloid leukemia (AML) is believed to arise from leukemic stem-like cells (LSC) making understanding the biological differences between LSC and normal stem cells (HSC) or common myeloid progenitors (CMP) crucial to understanding AML biology. To determine if protein expression patterns were different in LSC compared to other AML and CD34+ populations, we measured the expression of 121 proteins by Reverse Phase Protein Arrays (RPPA) in 5 purified fractions from AML marrow and blood samples: Bulk (CD3/CD19 depleted), CD34-, CD34+(CMP), CD34+CD38+ and CD34+CD38-(LSC). LSC protein expression differed markedly from Bulk (n=31 cases, 93/121 proteins) and CD34+ cells (n= 30 cases, 88/121 proteins) with 54 proteins being significantly different (31 higher, 23 lower) in LSC than in either Bulk or CD34+ cells. Sixty-seven proteins differed significantly between CD34+ and Bulk blasts (n=69 cases). Protein expression patterns in LSC and CD34+ differed markedly from normal CD34+ cells. LSC were distinct from CD34+ and Bulk cells by principal component and by protein signaling network analysis which confirmed individual protein analysis. Potential targetable submodules in LSC included the proteins PU.1(SP1), P27, Mcl1, HIF1α, cMET, P53, Yap, and phospho-Stats 1, 5 and 6. Protein expression and activation in LSC differs markedly from other blast populations suggesting that studies of AML biology should be performed in LSC.
Resistance to tyrosine kinase inhibitors in patients with chronic myeloid leukemia (CML) and Philadelphia chromosome–positive acute lymphoblastic leukemia (Ph-positive ALL) is frequently caused by mutations in the BCR-ABL kinase domain. Ponatinib (AP24534) is a potent oral tyrosine kinase inhibitor that blocks native and mutated BCR-ABL, including the gatekeeper mutant T315I, which is uniformly resistant to tyrosine kinase inhibitors.
In this phase 1 dose-escalation study, we enrolled 81 patients with resistant hematologic cancers, including 60 with CML and 5 with Ph-positive ALL. Ponatinib was administered once daily at doses ranging from 2 to 60 mg. Median follow-up was 56 weeks (range, 2 to 140).
Dose-limiting toxic effects included elevated lipase or amylase levels and pancreatitis. Common adverse events were rash, myelosuppression, and constitutional symptoms. Among Ph-positive patients, 91% had received two or more approved tyrosine kinase inhibitors, and 51% had received all three approved tyrosine kinase inhibitors. Of 43 patients with chronic-phase CML, 98% had a complete hematologic response, 72% had a major cytogenetic response, and 44% had a major molecular response. Of 12 patients who had chronic-phase CML with the T315I mutation, 100% had a complete hematologic response and 92% had a major cytogenetic response. Of 13 patients with chronic-phase CML without detectable mutations, 100% had a complete hematologic response and 62% had a major cytogenetic response. Responses among patients with chronic-phase CML were durable. Of 22 patients with accelerated-phase or blast-phase CML or Ph-positive ALL, 36% had a major hematologic response and 32% had a major cytogenetic response.
Ponatinib was highly active in heavily pretreated patients with Ph-positive leukemias with resistance to tyrosine kinase inhibitors, including patients with the BCR-ABL T315I mutation, other mutations, or no mutations. (Funded by Ariad Pharmaceuticals and others; ClinicalTrials.gov number, NCT00660920.)
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.
Allogeneic hematopoietic cell transplantation (HCT) is curative for selected patients with advanced essential thrombocythemia (ET) or polycythemia vera (PV). From 1990 to 2007, 75 patients with ET (median age 49 years) and 42 patients with PV (median age 53 years) underwent transplantations at the Fred Hutchinson Cancer Research Center (FHCRC; n = 43) or at other Center for International Blood and Marrow Transplant Research (CIBMTR) centers (n = 74). Thirty-eight percent of the patients had splenomegaly and 28% had a prior splenectomy. Most patients (69%for ET and 67%for PV) received a myeloablative (MA) conditioning regimen. Cumulative incidence of neutrophil engraftment at 28 days was 88% for ET patients and 90% for PV patients. Acute graft-versus- host disease (aGVHD) grades II to IV occurred in 57% and 50% of ET and PV patients, respectively. The 1-year treatment-related mortality (TRM) was 27% for ET and 22% for PV. The 5-year cumulative incidence of relapse was 13% for ET and 30% for PV. Five-year survival/progression-free survival (PFS) was 55%/47%and 71%/48% for ET and PV, respectively. Patients without splenomegaly had faster neutrophil and platelet engraftment, but there were no differences in TRM, survival, or PFS. Presence of myelofibrosis (MF) did not affect engraftment or TRM. Over 45% of the patients who undergo transplantations for ET and PV experience long-term PFS.
Transplantation; PV; ET
The authors have recently shown that a majority of patients with myelodysplastic syndrome (MDS) classified by the International Prognostic Scoring System as lower risk die without transformation to acute myelogenous leukemia (AML). The cause of death (COD) of these patients is not well understood. Identifying the COD could help to guide early therapy decisions.
The authors retrospectively analyzed the COD in a cohort of 273 deceased patients with lower-risk MDS according to the International Prognostic Scoring System at presentation to The University of Texas M. D. Anderson Cancer Center from 1980 to 2004. MDS-related death was defined as infection, bleeding, transformation to AML, or disease progression. Remaining CODs were classified as non–MDS-related.
Median age at presentation was 66 years (range, 19-88 years). Overall median survival was 59 weeks (range, 1-831 weeks). All French-American-British leukemia classification subgroups were represented. The percentage of International Prognostic Scoring System low and intermediate-1 groups were 21% and 79%, respectively. The most common cytogenetic abnormality (9%) was del(5q). Patients received supportive care only. The COD was identified as MDS-related in 230 of 273 (84%) patients. The most common disease-related CODs were infection (38%), transformation to AML (15%), and hemorrhage (13%). The most frequent non–disease-related COD was cardiovascular events (19 of 43 patients).
The majority of patients with low- or intermediate-1 risk MDS will die because of causes related to their underlying disease. Although these results need to be validated in different populations, early therapeutic intervention could be considered in the management of these patients to improve survival.
myelodysplastic syndrome; mortality; International Prognostic Scoring System; cause of death
The annual incidence of chronic myeloid leukemia (CML) in the United States is about 4800 cases. With the success of tyrosine kinase inhibitor (TKI) therapy, the all-cause annual mortality rate was reduced to 2%. The prevalence of CML is therefore increasing over time. Estimating the CML prevalence and plateau prevalence is important in the implementation of healthcare strategies and future therapeutic trials.
Estimate the increasing prevalence and plateau prevalence of CML in future years.
The prevalence of CML was estimated based on several parameters: annual mortality rate on TKI therapy compared to age-matched normal population, incidence of CML, anticipated population growth in the United States, aging of the population.
Based on these calculations, the mortality ratio of patients with CML compared to an age-matched normal population is about 1.53. The prevalence of CML is estimated to be about 70,000 in 2010, 112,000 in 2020, 144,000 in 2030, 167,000 in 2040 and 181,000 in 2050 when it reaches a near plateau prevalence.
The prevalence of CML will continue to increase to reach a near plateau prevalence 35 times the annual incidence. These estimates should be considered in healthcare policies and in the design of future studies in CML.
The long-term outcome of patients with chronic phase chronic myeloid leukemia treated with imatinib after failure of interferon alpha therapy has not been detailed.
Patients and Methods
368 patients were analyzed. Univariate and multivariate analyses for survival were conducted using standard statistical methods.
Overall, 247 patients (67%) achieved complete cytogenetic response (CCyR). Of 327 patients studied, 207(63%) achieved major molecular response (MMR), and 99 (30%) had undetectable BCR-ABL levels at some time on therapy. The estimated 10-year survival rate was 68%, progression-free survival rate 67%, and event-free survival rate 51%. By multivariate analysis, age ≥ 60 years, hemoglobin < 10g/dl, marrow basophils ≥ 5%, any peripheral blasts, and clonal evolution were independent adverse factors for survival. The estimated 7-year survival by the presence of none (n=154), 1-2 (n=190), or ≥ 3 factors (n=24) were 93%, 70%, and 25% respectively (p <0.01). Achievement of MMR, CCyR, or partial cytogenetic response at 12 months were associated with significantly better 10-year survival rate by landmark analysis (10-year survival 80-90%) vs. achieving minor cytogenetic response or complete hematologic response (10-year survival 55-65%) vs. other response (10-year survival 10%). Using landmark analysis to include imatinib response at 12 months, achievement of major cytogenetic response or better (hazard ratio 0.12; p< 0.001) and complete hematologic response or minor cytogenetic response (hazard ratio 0.36; p=0.003) were significant favorable prognostic factors.
The estimated 10-year survival rate of 68% in patients with chronic myeloid leukemia receiving imatinib after interferon failure has improved.
Cardiac dysfunction, particularly QT interval prolongation, has been observed with tyrosine kinase inhibitors approved to treat chronic myeloid leukemia. This study examines the effects of ponatinib on cardiac repolarization in patients with refractory hematological malignancies enrolled in a phase 1 trial.
Electrocardiograms (ECGs) were collected at 3 dose levels (30, 45, and 60 mg) at 6 time points. Electrocardiographic parameters, including QTc interval, were measured, and 11 morphological analyses were conducted. Central tendency analyses of ECG parameters were performed using time-point and time-averaged approaches. All patients with at least 2 baseline ECGs and 1 on-treatment ECG were included in the analyses. Patients with paired ECGs and plasma samples were included in the pharmacokinetic/pharmacodynamic analysis to examine the relationship between ponatinib plasma concentration and change from baseline in QT intervals.
Thirty-nine patients at the 30-, 45-, and 60-mg dose levels were included in the central tendency and morphological analyses. There was no significant effect on cardiac repolarization, as evidenced by non-clinically significant mean QTcF changes from baseline of −10.9, −3.6, and −5.0 ms for the 30-, 45-, and 60-mg dose levels, respectively. The morphological analysis revealed 2 patients with atrial fibrillation and 2 with T wave inversion. Seventy-five patients were included in the pharmacokinetic/pharmacodynamic analysis across all dose levels. The slope of the relationship for QTcF versus plasma ponatinib concentration was not positive (−0.0171), indicating no exposure–effect relationship.
Ponatinib is associated with a low risk of QTc prolongation in patients with refractory hematological malignancies.
Ponatinib; BCR-ABL; Chronic myeloid leukemia; Philadelphia chromosome; Drug safety; Electrocardiography
Since its approval in 2001 for frontline management of chronic myelogenous leukemia (CML), imatinib has proven to be very effective in achieving high remission rates and improving prognosis. However, up to 33% of patients will not achieve optimal response. This has led researchers to develop new second- and third-generation tyrosine kinase inhibitors. In this article, we review the mechanisms of resistance, recommendations for monitoring, assessment of milestones, and management options for patients with CML who are resistant to imatinib therapy. We further explain the potential pitfalls that can lead to unnecessary discontinuation, the prognosis of patients whose condition fails to respond to treatment, and the upcoming therapies.
CML; imatinib resistance; treatment; tyrosine kinase inhibitor
The epidemiology of candidemia varies depending on the geographic region. Little is known about the epidemiology of candidemia in Latin America.
We conducted a 24-month laboratory-based survey of candidemia in 20 centers of seven Latin American countries. Incidence rates were calculated and the epidemiology of candidemia was characterized.
Among 672 episodes of candidemia, 297 (44.2%) occurred in children (23.7% younger than 1 year), 36.2% in adults between 19 and 60 years old and 19.6% in elderly patients. The overall incidence was 1.18 cases per 1,000 admissions, and varied across countries, with the highest incidence in Colombia and the lowest in Chile. Candida albicans (37.6%), C. parapsilosis (26.5%) and C. tropicalis (17.6%) were the leading agents, with great variability in species distribution in the different countries. Most isolates were highly susceptible to fluconazole, voriconazole, amphotericin B and anidulafungin. Fluconazole was the most frequent agent used as primary treatment (65.8%), and the overall 30-day survival was 59.3%.
This first large epidemiologic study of candidemia in Latin America showed a high incidence of candidemia, high percentage of children, typical species distribution, with C. albicans, C. parapsilosis and C. tropicalis accounting for the majority of episodes, and low resistance rates.
Despite being highly effective for newly diagnosed chronic myeloid leukemia (CML), imatinib not only is inactive against quiescent CML stem cells, but also has limited activity against blast crisis (BC) CML. The relative activity of Bcr-Abl and the expression levels of antiapoptotic proteins in proliferating and quiescent CD34+ BC CML progenitor cells and the effects of targeting antiapoptotic proteins in these cells are unknown. Here we report higher levels of p-CrkL in quiescent than in proliferating CD34+ progenitor cells and comparable expression levels of Bcl-2, Bcl-xL, Mcl-1, and XIAP in the two populations in BC CML. Inhibition of Bcl-2/Bcl-xL by ABT-737 in cells from patients with tyrosine kinase inhibitor (TKI)-resistant BC CML promoted apoptosis in quiescent CD34+ progenitor cells with an efficacy similar to that in proliferating cells. Combination of ABT-737 with imatinib (which decreases Mcl-1 levels) or triptolide (which decreases Mcl-1 and XIAP) synergistically induced death of both proliferating and quiescent CD34+ progenitor cells obtained from TKI-resistant BC CML patients. These results suggest that antiapoptotic proteins are critical targets in BC CML and that activation of apoptosis signaling can eliminate both proliferating and quiescent CD34+ progenitor cells in BC CML, independent of response to TKIs.
apoptosis; Bcl-2/Bcl-xL; Mcl-1; XIAP; quiescent; CML; progenitors