Pharmacokinetics of CPX-351; a nano-scale liposomal fixed molar ratio formulation of cytarabine:daunorubicin, in patients with advanced leukemia.

Forty-eight patients received CPX-351 (liposome-encapsulated cytarabine:daunorubicin at a 5:1 molar ratio) every other day for 3 doses at 10 dose levels. Pharmacokinetic parameters were dose-independent and exhibited low inter-patient variability. CPX-351 showed a negligible distribution phase and prolonged mono-exponential first-order plasma elimination (t(1/2)∼24 h). The plasma ratio of 5:1 was maintained at all dose levels. Nearly all of the detectable cytarabine and daunorubicin in circulation following CPX-351 administration was in the form of liposome encapsulated drug. Dose-dependent hematopoietic effects had early onset with cytopenias at 12 units/m(2), and a gradual increase in frequency and severity, until single induction complete response was achieved at 43 units/m(2). Non-hematologic effects had onset by 24 units/m(2) with shallow dose-response until maximum frequency and severity were observed at the 101-134 units/m(2) dose levels. Single induction response occurred over a 2.3-fold range of doses indicating that CPX-351 may be useful at high doses for patients suitable for intensive chemotherapy and at reduced doses for patients at increased risk of treatment-related mortality. The unique pharmacologic features of CPX-351 contribute to its promising antileukemic efficacy.

Management of refractory acute myeloid leukemia: re-induction therapy or straight to transplantation?

Patients with primary resistant and relapsed acute myeloid leukemia (AML) are rarely cured without undergoing allogeneic stem cell transplantation. What is currently debated is whether a trial of re-induction chemotherapy prior to transplantation is beneficial. Data from multiple retrospective analyses have shown that pretreatment variables are useful in predicting response to salvage chemotherapy. For patients unlikely to respond, re-induction attempts may be detrimental, leading to added organ toxicity and possible increased tumor resistance. Allogeneic transplantation in the setting of active disease is the alternative strategy. Multiple studies have demonstrated the feasibility of this approach, but cure rates have been low with the use of traditional transplant approaches. Newer strategies employing allogeneic transplantation earlier in patients with relapsed or refractory AML, as well as the incorporation of novel and effective antileukemic agents into the transplant conditioning regimen, may lead to better outcomes.

Differences in platelet function in patients with acute myeloid leukemia and myelodysplasia compared to equally thrombocytopenic patients with immune thrombocytopenia.

BACKGROUND: Severe thrombocytopenia is a major risk factor for hemorrhage, but platelet function and bleeding risk at low platelet counts are poorly understood, because of the limitations of platelet function testing at very low platelet counts. OBJECTIVES: To examine and compare platelet function in severely thrombocytopenic patients with acute myeloid leukemia (AML) or myelodysplasia (MDS) with that in patients with immune thrombocytopenia (ITP). METHODS: Whole blood flow cytometric measurement of platelet activation and platelet reactivity to agonists was correlated with the immature platelet fraction (IPF) and bleeding symptoms. RESULTS: Patients with AML/MDS had smaller platelets, lower IPF and substantially lower platelet surface expression of activated glycoprotein (GP)IIb-IIIa and GPIb, both with and without addition of ex vivo ADP or thrombin receptor-activating peptide, than patients with ITP. In both ITP and AML/MDS patients, increased platelet surface GPIb on circulating platelets and expression of activated GPIIb-IIIa and GPIb on ex vivo activated platelets correlated with a higher IPF. Whereas platelet reactivity was higher for AML/MDS patients with bleeding than for those with no bleeding, platelet reactivity was lower for ITP patients with bleeding than for those with no bleeding. CONCLUSIONS: AML/MDS patients have lower in vivo platelet activation and ex vivo platelet reactivity than patients with ITP. The proportion of newly produced platelets correlates with the expression of platelet surface markers of activation. These differences might contribute to differences in bleeding tendency between AML/MDS and ITP patients. This study is the first to define differences in platelet function between AML/MDS patients and ITP patients with equivalent degrees of thrombocytopenia.

On the use of lonafarnib in myelodysplastic syndrome and chronic myelomonocytic leukemia.

Lonafarnib is an orally bio-available farnesyltransferase inhibitor that prevents farnesylation of specific target proteins including Ras. In a multicenter study, 67 patients with advanced myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) were treated with a continuous oral dose of 200-300 mg of lonafarnib and were evaluated for hematologic, pathologic and pharmacodynamic response. The median age of patients was 70 years (range 44-86). There were 32 patients with MDS (RAEB-20 and RAEB-t-12) and 35 with CMML. Overall 16 (24%) of the patients responded with two patients achieving a complete remission and one a partial response. Responses were seen in 6/32 and 10/35 patients with MDS and CMML, respectively. Of the 19 patients who were platelet transfusion-dependent prior to treatment, 5 (26%) became transfusion-free for a median duration of 185 days. A decrease in the farnesylation of the HDJ-2 protein measured in patient-derived cells was observed in the majority of patients during treatment with lonafarnib, but no clear correlation between changes in farnesylation and clinical effect could be made. Gastrointestinal toxicity was significant with 19% of patients discontinuing therapy due to diarrhea, nausea and/or anorexia. Lonafarnib has demonstrable activity in patients with advanced MDS and CMML.

Intensive treatment strategies may not provide superior outcomes in mantle cell lymphoma: overall survival exceeding 7 years with standard therapies.

BACKGROUND: Reported median overall survival (OS) in patients with mantle cell lymphoma (MCL) has been reported to be just 3-4 years. As a consequence, first-line treatment has become more aggressive. Single-center studies with R-Hyper-CVAD and/or autologous stem-cell transplant (ASCT) have produced 3-year OS rates >80%, prompting many to adopt their use. We evaluated outcomes from a single-center cohort managed in a more traditional fashion. METHODS: We identified patients with MCL evaluated at Weill Cornell Medical Center since 1997, and included those with known date of diagnosis. An online social security database was used to verify survival. RESULTS: We identified 181 patients with MCL, and date of diagnosis could be determined in 111. Three-year OS from diagnosis was 86% [95% confidence interval (CI) 78% to 92%]. Median OS was 7.1 years (95% CI 63-98 months). Adequate information on therapy was available for 75 patients. Only five were treated upfront with (R)-Hyper-CVAD or ASCT while an additional four patients received one of these regimens subsequently. Treatment type had no significant effect on OS. CONCLUSION: Outcomes with standard approaches can yield similar survival to that achieved with more intensive approaches. Biases may account for the perceived superiority of aggressive strategies.

Activation of FGFR1beta signaling pathway promotes survival, migration and resistance to chemotherapy in acute myeloid leukemia cells.

Fibroblast growth factors (FGFs) are important regulators of hematopoiesis and have been implicated in the tumorigenesis of solid tumors. Recent evidence suggests that FGF signaling through FGF receptors (FGFRs) may play a role in the proliferation of subsets of acute myeloid leukemias (AMLs). However, the precise mechanism and specific FGF receptors that support leukemic cell growth are not known. We show that FGF-2, through activation of FGFR1beta signaling, promotes survival, proliferation and migration of AML cells. Stimulation of FGFR1beta results in phosphoinositide 3-kinase (PI3-K)/Akt activation and inhibits chemotherapy-induced apoptosis of leukemic cells. Neutralizing FGFR1-specific antibody abrogates the physiologic and chemoprotective effects of FGF-2/FGFR1beta signaling and inhibits tumor growth in mice xenotransplanted with human AML. These data suggest that activation of FGF-2/FGFR1beta supports progression and chemoresistance in subsets of AML. Therefore, FGFR1 targeting may be of therapeutic benefit in subsets of AML.

Phase 1 study of PTK787/ZK 222584, a small molecule tyrosine kinase receptor inhibitor, for the treatment of acute myeloid leukemia and myelodysplastic syndrome.

PTK787/ZK 222584 (PTK/ZK) is an oral angiogenesis inhibitor targeting vascular endothelial growth factor (VEGF) receptor tyrosine kinases, including VEGFR-1/Flt-1, VEGFR-2/KDR, VEGFR-3/Flt-4, the platelet-derived growth factor receptor tyrosine kinase and the c-kit protein tyrosine kinase. The objective of this Phase I study was to evaluate the safety, tolerability, biologic activity and pharmacologic profile of PTK/ZK administered orally, twice daily, on a continuous dosing schedule in patients with primary refractory or relapsed acute myeloid leukemia (AML), secondary AML, poor-prognosis de novo AML or advanced myelodysplastic syndrome (MDS). Acute myeloid leukemia patients for whom PTK/ZK monotherapy was ineffective could receive PTK/ZK combined with standard induction chemotherapy. Sixty-three patients received PTK/ZK at doses of 500-1000 mg orally b.i.d. Safety and pharmacokinetic data were collected. Responses were evaluated according to standard bone marrow and peripheral blood criteria. At 1000 mg b.i.d., dose-limiting toxicities of lethargy, hypertension, nausea, emesis and anorexia were observed. Other adverse events related to PTK/ZK were dizziness, weakness, fatigue, diarrhea and pruritus; these were generally mild and reversible. Pharmacokinetic data showed that steady state was reached by day 14, there was no accumulation with repeat dosing and there was no significant increase in exposure at steady state beyond the maximum tolerated dose (MTD). Complete remission was observed in five of 17 AML patients treated with PTK/ZK combined with chemotherapy. In conclusion, the MTD of PTK/ZK is 750 mg orally b.i.d. The drug is generally well tolerated and can be given in combination with chemotherapy for patients with MDS and AML.

Farnesyltransferase inhibitors in myelodysplastic syndrome.

The farnesyltransferase inhibitors (FTIs) are in active clinical development in a variety of human malignancies. The most promising activity to date has been demonstrated in patients with hematologic malignancies, in particular acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). In patients with MDS, two nonpeptidomimetic agents, tipifarnib (Zarnestra, Johnson & Johnson, New Brunswick, NJ) and lonafarnib (Sarasar, Schering-Plough, Kenilworth, NJ) have been the most extensively studied. In both phase I and phase II trials, tipifarnib has demonstrated significant efficacy, with overall response rates of 30% and complete remissions in about 15%. Dose-limiting adverse effects have been primarily myelosuppression, although fatigue, neurotoxicity, and occasional renal dysfunction have required dose reductions. Lonafarnib in patients with MDS has also resulted in clinical responses in approximately 30%, including significant improvements in platelet counts. Lonafarnib has been associated primarily with diarrhea and other gastrointestinal toxicity, anorexia, and nausea, which has limited its efficacy. Clinical response correlation with documentation of inhibition of farnesyltransferase and/or evidence of decreased farnesylation of downstream protein targets has not been demonstrated with either agent. In addition, the presence of an activating Ras mutation has not predicted response to therapy with FTIs in MDS and AML. Despite this lack of evidence, significant clinical efficacy of the FTIs has been observed in MDS, on a par with the efficacy of currently available chemotherapeutic agents, leading to further development of this new class of drugs in MDS and AML.

Farnesyltransferase inhibitors in myelodysplastic syndrome.

The farnesyltransferase inhibitors (FTIs) are in active clinical development in a variety of human malignancies. The most promising activity to date has been demonstrated in patients with hematological malignancies, in particular acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). In patients with MDS, two non-peptidomimetic agents, tipifarnib (Zarnestra, Johnson & Johnson, New Brunswick, NJ) and lonafarnib (Sarasar, Schering-Plough, Kenilworth, NJ) have been the most extensively studied. In both phase I and phase II trials, tipifarnib has demonstrated significant efficacy with overall response rates of 30%, with complete remissions in about 15%. Dose-limiting side effects have been primarily myelosuppression, although fatigue, neurotoxicity, and occasional renal dysfunction have required dose reductions. Lonafarnib in patients with MDS has also resulted in clinical responses in approximately 30%, including significant improvements in platelet counts. Lonafarnib has been associated with primarily diarrhea and other gastrointestinal toxicity, anorexia, and nausea, which has limited its efficacy. Clinical response correlation with documentation of inhibition of farnesyltransferase and/or evidence of decreased farnesylation of downstream protein targets has not been demonstrated with either agent. In addition, the presence of an activating Ras mutation has not predicted response to therapy with FTIs in MDS and AML. Despite this, significant clinical efficacy of the FTIs in MDS, on par with that of currently available chemotherapeutic agents, has been observed, leading to further development of this new class of drugs in MDS and AML.

Efficacy and safety of gemtuzumab ozogamicin in patients with poor-prognosis acute myeloid leukemia.

The objective of this work was to determine the safety and efficacy of gemtuzumab ozogamicin in patients with poor prognosis acute myeloid leukemia (AML). Patients with the following diagnoses/characteristics were treated with 1-3 infusions of gemtuzumab ozogamicin at a dose of 9 mg/m2: (1) relapse of AML < or = 6 months of first complete remission (CR); (2) AML refractory to chemotherapy at initial induction or at first relapse; (3) AML in second or greater relapse; (4) myeloid blast crisis of chronic myeloid leukemia (CML); (5) untreated patients > or = 70 years or > or = 55 years with abnormal cytogenetics (excluding inv 16, t(15;17) and t(8;21)) and/or an antecedent hematologic disorder; (6) refractory anemia with excess blasts in transformation (RAEBT). Forty-three patients, ages 19-84 (mean 62), were treated, including 7 patients with untreated AML age > 70 years, 2 with untreated RAEBT, 14 with AML first salvage (first remission 0-6 months), 15 with AML > or = second salvage and 14 with myeloid blast phase of CML. The overall response rate was 14%, with 4/43 (9%) patients achieving CR and 2/43 (5%) achieving CR without platelet recovery. The most significant toxicity was neutropenic fever, which occurred in 84% of patients. In conclusion, in patients with relapsed/refractory AML, gemtuzumab ozogamicin has a comparable response rate to single-agent chemotherapy and may offer a more favorable toxicity profile.

Intravenous bolus topotecan in patients with myelodysplastic syndrome.

We treated 16 patients with myelodysplastic syndromes with 24 courses of bolus topotecan. Patients received topotecan as a daily 15 minute infusion for 5 days at 3 dose levels (4.0 mg/m2/d, 2.0 mg/m2/d or 2.5 mg/m2/d). There was one complete response and one partial response (overall response rate 12%). Toxicity included myelosuppression, diarrhea, ileus and mucositis. There were 3 treatment-related deaths. The results of this schedule of topotecan appeared to be inferior to that reported with infusional topotecan in patients with MDS.

Secondary acute myelogenous leukemia and myelodysplasia without abnormalities of chromosome 11q23 following treatment of acute leukemia with topoisomerase II-based chemotherapy.

Therapy-related MDS and AML are complications of intensive chemotherapy regimens. Traditionally, patients exposed to topoisomerase II inhibitors are reported to develop secondary AML with abnormalities of chromosome 11q23. We evaluated the long-term hematologic toxicity of topoisomerase II-intensive high-dose mitoxantrone-based chemotherapy in 163 newly diagnosed acute leukemia patients treated over an 8 year period. Nine (5.5%) patients developed new cytogenetic abnormalities. Four patients developed MDS with progression to AML, three patients developed new abnormalities at the time of relapse, and three patients (including one of the former patients) had changes that were not associated with hematologic disease. The abnormalities most frequently involved chromosomes 7q, 20q, 1q, and 13q. Despite the use of topoisomerase II-intensive treatment, no patient developed an abnormality involving chromosome 11q23. Spontaneous resolution of some changes and prolonged persistence of others in the absence of hematologic disease indicates that some cytogenetic changes are not sufficient to promote leukemogenesis.

Phase II evaluation of a high-dose mitoxantrone based induction regimen in untreated adults with acute myeloid leukemia.

To evaluate a regimen including high-dose mitoxantrone in previously untreated adults with AML, 45 patients aged 21-59 (median 41) were given cytarabine, 3 g/m2 days 1-5, mitoxantrone, 80 mg/m2 day 2 and etoposide, 150 mg/m2 days 1,3,5. Post-remission therapy consisted of 5 cycles combining the same agents at reduced doses. Complete remission was seen in 36 patients. The observed 3-year survival is 28%. Cytogenetic pattern and CD34 expression correlated with response and survival. Significant toxicity included myelosuppression, mucositis, diarrhea and hyperbilirubinemia. Ventricular ejection fraction was generally reduced, with clinical cardiac dysfunction in only 2 patients. This high-dose mitoxantrone combination can be administered to young adults with AML with tolerable toxicity and results comparable to those of other dose-intensive regimens.

Clinical and laboratory evaluation of all-trans retinoic acid modulation of chemotherapy in patients with acute myelogenous leukaemia.

All-trans retinoic acid (ATRA) is synergistic with chemotherapy in leukaemia cell lines. We treated 53 patients with newly diagnosed acute myelogenous leukaemia (AML) with high-dose cytarabine-based chemotherapy followed by ATRA. Peripheral blood and bone marrow samples were obtained to study the effect of in vitro exposure to ATRA and to measure apoptosis and bcl-2. The response rate was 72% for patients under age 60 years and 46% for patients aged 60 years or above. There was no difference in the percentage of responding patients, time to recurrence or overall survival for patients receiving chemotherapy with ATRA vs. historical controls receiving chemotherapy without ATRA. After in vitro exposure of day 3 bone marrow samples to ATRA, there was an increase in apoptotic cells in 25% of patient samples compared with samples not exposed to ATRA. Later date of peak apoptosis in peripheral blood and higher percentage of apoptotic cells in bone marrow on day 3 of treatment were associated with lack of clinical response to treatment. Increased bcl-2 in patient samples was associated with shorter time to recurrence and poor cytogenetic risk. The addition of ATRA to chemotherapy did not improve patient outcome. However, evidence of in vitro response to ATRA in 25% of patients suggests that retinoid pathways should be studied further in patients with AML.

A phase I-II trial of escalating doses of mitoxantrone with fixed doses of cytarabine plus fludarabine as salvage therapy for patients with acute leukemia and the blastic phase of chronic myelogenous leukemia.

BACKGROUND: Cytarabine is an essential drug for inducing remission of acute myelogenous leukemia, and it is also one the most effective drugs used as salvage therapy for patients with all types of relapsed acute leukemia. Nevertheless, there is considerable room for improvement in the treatment of patients with relapsed leukemia in terms of both the reinduction rate and the duration of response. Fludarabine has been shown to augment responses to cytarabine, possibly by increasing the intracellular concentrations of the active metabolite cytarabine triphosphate. Higher-than-standard doses of mitoxantrone have been shown to augment responses to cytarabine, possibly by increasing the DNA strand breaks induced by topoisomerase II; these strand breaks cannot be effectively repaired in the presence of cytarabine triphosphate. This preliminary study was designed to determine whether moderately high doses of mitoxantrone could be added to the combination of fludarabine and cytarabine in an attempt to improve the combination's antileukemic efficacy. METHODS: Fifty-five adults with relapsed or refractory acute leukemia or the blastic phase of chronic myelogenous leukemia (CML) received salvage therapy with the FLAM regimen, which consisted of fludarabine, cytarabine, and increasing doses of mitoxantrone. RESULTS: Even with doses of mitoxantrone escalated to as much as 60 mg/m(2) over 4 days, dose-limiting toxicity was not observed. Overall, the complete response rate was 27.3% (15 of 55 patients, including 4 of 17 with acute myelogenous leukemia [AML], 4 of 12 with acute lymphocytic leukemia [ALL], and 7 of 26 with the blastic phase of CML). The median time to complete response was 42 days. Toxicity other than myelosuppression was manifested primarily as hyperbilirubinemia, which was reversible in all cases. Poor performance status and undifferentiated blastic phase of CML were poor prognostic factors for response to FLAM. CONCLUSIONS: The FLAM regimen is an active salvage regimen and should be formally evaluated in Phase II studies of patients with AML, ALL, and the myeloid and lymphoid blastic phases of CML.

Therapy-related myelodysplastic syndrome in adults with neurofibromatosis.

Although an increased risk of hematologic malignancies in children with Neurofibromatosis-1 (NF-1) is well established, whether adults with NF-1 have an increased risk of such malignancies is unclear. We currently describe two adult patients with NF-1 who rapidly developed secondary myelodysplastic syndromes with abnormalities of chromosome 7 following chemotherapy for AML. We propose that adults with NF-1 also have abnormalities of hematologic progenitor cells.

Malignancy: A New Approach to the Analysis of Apoptosis in the Leukemic Subpopulation by Flow Cytometry Using a CD45 Gating Strategy.

Bone marrow and peripheral blood are heterogeneous tissues containing cells of different hematopoietic lineages. It is possible to detect leukemic cells by flow cytometry using a gating strategy, which combines CD45 expression on the cell surface with right angle light scatter (SS). This approach was applied to 15 cases of AML. Myeloblasts had the lowest CD45 fluorescence intensity of any of the cells in the myeloid series and also had the lowest SS, approximately equivalent to monocytes, but greater than lymphoblasts and lymphocytes. Using this gating strategy in each sample we could identify up to 5 separate cell compartments. Our results showed good correlation between the flow differential and the manual differential cell count. However in some cases, especially when a sample became hypocellular, the flow differential was more sensitive in identifying leukemic blasts. Total apoptosis (i.e. apoptosis in all cell populations combined) varied during the treatment between 0-34%. In the blood, the highest percentage of total apoptotic cells usually occurred between day 3-5 of treatment. The percentage of apoptotic cells varied depending on the cell type on a percentage basis. The leukemic population was lesslikely to undergo apoptosis compared to the lymphocytes, monocytes and more mature myeloid cells. In normal cells, apoptosis occurred mostly in G(1) and S phases of the cell cycle. Apoptosis among CD45-blasts usually varied between 0-5%. Myeloblasts also had a tendency to undergo apoptosis in G(1) and S phases of the cell cycle. The CD45-blast apoptotic peak in the blood occurred between day 5-7 of treatment. Analysis of drug-induced apoptosis in bone marrow seems to provide more information than such measurements in peripheral blood.