Phase I and pharmacokinetic study of Triapine, a potent ribonucleotide reductase inhibitor, in adults with advanced hematologic malignancies.

Triapine, a potent inhibitor of ribonucleotide reductase, has demonstrated anti-leukemia activity in pre-clinical models. We conducted a Phase I study of Triapine administered as a 2 h infusion for 5 days in 25 adults with advanced leukemias. We established that Triapine at 96 mg/m2 once a day can be given safely on days 1-5 and 15-19 or 1-5 and 8-12 of a 4-week cycle. When administered twice a day on days 1-5 and 8-12, the maximum tolerated dose of Triapine appears to be 64 mg/m2, although the true criteria for DLT were not met by protocol definition. No CR or PR were observed, but 76% of patients had a >50% reduction in white blood cell counts. At all dose levels, the peak plasma concentration of Triapine (2.2-5.5 microM) was above levels required to achieve in vitro/in vivo leukemia growth inhibition. Based on these data, we conclude that Triapine warrants further investigation in hematologic malignancies.

Phase I and pharmacokinetic study of flavopiridol followed by 1-beta-D-arabinofuranosylcytosine and mitoxantrone in relapsed and refractory adult acute leukemias.

PURPOSE: The serine/threonine kinase inhibitor flavopiridol targets multiple cyclin-dependent kinases, induces checkpoint arrest, and interrupts transcriptional elongation. We designed a phase I clinical trial using a timed sequential therapy approach where flavopiridol was given for the dual purpose of initial cytoreduction and enhancing cell cycle progression of the remaining leukemia cell cohort followed by cycle-dependent drugs 1-beta-D-arabinofuranosylcytosine (ara-C) and mitoxantrone. EXPERIMENTAL DESIGN: Flavopiridol was given by 1-hour infusion daily for 3 days beginning day 1 followed by 2 g/m2/72 h ara-C beginning day 6 and 40 mg/m2 mitoxantrone beginning day 9. In vivo correlates included pharmacokinetics, modulation of blast cycle regulators, and serum and marrow supernatant vascular endothelial growth factor levels. RESULTS: Of 34 adults receiving induction therapy, 16 (47%) evinced direct leukemia cytotoxicity with > or =50% drop in peripheral blast counts and tumor lysis in 9 (26%). Four (12%) died during therapy (two fungal infections and two sudden death). Dose-limiting toxicity occurred at 60 mg/m2/d with profound neutropenia >40 days duration, and maximal tolerated dose was 50 mg/m2/d. Overall response rate was 31% in 26 acute myelogenous leukemia and 12.5% in acute lymphoblastic leukemia. Pharmacokinetics showed that a linear two-compartment model with first-order elimination provided the best fit of the observed concentration versus time data. Flavopiridol down-regulated one or more target proteins in marrow blasts in vivo. Vascular endothelial growth factor was detected in sera and marrow supernatant pretreatment, and sera obtained on day 3 inhibited bovine aortic endothelial cell proliferation by a mean of 32% (range, 10-80%). CONCLUSIONS: Our data suggest that flavopiridol is cytotoxic to leukemic cells and, when followed by ara-C and mitoxantrone, exerts biological and clinical effects in patients with relapsed and refractory acute leukemias. These findings warrant continuing development of flavopiridol at 50 mg/m2/d x 3 days in combination with cytotoxic and biological agents for acute leukemias.

Timed sequential therapy of acute leukemia with flavopiridol: in vitro model for a phase I clinical trial.

PURPOSE: The survival of adults with acute leukemias remains unsatisfactory and requires new treatment approaches. Flavopiridol modulates cell cycle progression, inhibits transcription, and induces apoptosis. We designed an in vitro model of timed sequential therapy for acute leukemia to determine whether flavopiridol can: (a). trigger apoptosis in fresh acute leukemia; and (b). recruit surviving leukemic cells to a proliferative state, thereby priming such cells for the S-phase-related cytotoxicity of 1-beta-D-arabinofuranosylcytosine (ara-C). EXPERIMENTAL DESIGN: Bone marrow cells from 20 adults with relapsed and refractory acute leukemias were enriched for blasts by Ficoll Hypaque sedimentation. Blasts were cultured on day 0 in flavopiridol 250 nM for 24 h, removed from flavopiridol for 24 h, and then cultured in ara-C 1 microM for an additional 72 h (F(250)A(1)). Apoptosis and cell cycle phase distribution were estimated from cells stained with propidium iodide. Cell survival was determined after the 72 h ara-C exposure by double cytofluorescence assay with fluorescein diacetate and propidium iodide. RESULTS: Flavopiridol induced a 4.3-fold increase in apoptosis in human leukemia samples within the first 24 h of culture. Subsequent removal of flavopiridol led to a 1.7-fold increase in the proportion of cells in S phase by day 2. Mean survival in F(250)A(1) cultures after 72 h exposure to ara-C was 35.6% compared with flavopiridol alone (F(250)A(0), 56.1%; P = 0.0003) and ara-C alone (F(0)A(1), 65.2%; P < 0.00001). CONCLUSIONS: Flavopiridol induces apoptosis in marrow blasts from patients with refractory acute leukemias. Furthermore, flavopiridol pretreatment increases the proapoptotic and cytotoxic effects of ara-C. The advantage of sequential FP(250)A(1) over either agent alone is seen for both acute myelogenous leukemia and acute lymphoblastic leukemia. These findings support a clinical trial of timed sequential therapy where flavopiridol is given for cytoreduction and subsequent priming of remaining leukemic cells for enhanced cycle-dependent drug cytotoxicity.

Treatment of catheter-related deep vein thrombosis in patients with acute leukemia with anticoagulation.

Patients with acute leukemia develop venous thrombosis (VT) related to central venous catheters (CVCs). Anticoagulation (AC) in these patients who are thrombocytopenic and often coagulopathic is challenging. To evaluate the safety and efficacy of AC in treating CVC-related VT, we retrospectively compared outcomes of patients with acute leukemia who were treated or not with AC during induction chemotherapy and post-discharge. Twenty-one patients with CVC-related VT received AC, 14 did not. VT resolved in 80% of patients in the AC group (similarly with low-dose and high-dose enoxaparin) and 45% in the non-AC group (p = 0.11). Fourteen (67%) patients in the AC group are alive (median survival not reached), compared to four patients (29%) in the non-AC group (median survival 9 months) (p = 0.015) with a hazard ratio (HR) of 0.32 (95% confidence interval: 0.12-0.85) in favor of AC. HR remained < 1 after adjustments for leukemia type and cytogenetics. Bleeding (< grade 4) occurred in five and one patients in the AC vs. non-AC groups, respectively (p = 0.37).

Lack of objective response of myelodysplastic syndromes and acute myeloid leukemia to decitabine after failure of azacitidine.

The hypomethylating agents azacitidine and decitabine are standard therapy for myelodysplastic syndromes (MDS), and are often used to treat patients with acute myeloid leukemia (AML) unlikely to benefit from cytotoxic chemotherapy. Switching hypomethylating agents after treatment failure is common, but this approach is not well studied. We retrospectively reviewed data on 25 patients with MDS, MDS/myeloproliferative neoplasm (MDS/MPN) or AML who were treated with decitabine after primary or secondary azacitidine failure at the University of Maryland Greenebaum Cancer Center. Five patients with MDS or MDS/MPN achieved stable disease with decitabine, but no patient achieved complete or partial remission or hematologic improvement. Most patients discontinued therapy due to disease progression or death after a median of 2 cycles and median survival was 5.9 months after decitabine initiation. Based on our data, decitabine therapy after azacitidine failure is of little benefit beyond disease stabilization in some patients.

Timed sequential therapy of acute myelogenous leukemia in adults: a phase II study of retinoids in combination with the sequential administration of cytosine arabinoside, idarubicin and etoposide.

Clinical outcome in acute myeloid leukemia (AML) is unsatisfactory. One strategy to augment cytotoxicity is TST. All-trans retinoic acid (ATRA) down-regulates bcl-2 expression and heightens AML sensitivity to cytosine arabinoside (ara-C)-induced apoptosis in vitro. We designed a trial of ATRA plus ara-C-based TST in an attempt to enhance drug-induced apoptosis and clinical outcome. Between January 1998 and February 2000, 63 patients received induction TST (oral ATRA days 1-6, ara-C and idarubicin days 2-4, VP-16 days 9-11) followed by consolidation TST (ATRA, ara-C and idarubicin followed by a second ara-C infusion days 11-13). Complete remission (CR) was 60%, with higher rates for patients of <60 years (79%), de novo AML (70%), and non-adverse cytogenetics (81%). Median disease-free survival (DFS) for CR patients was 11.2 months (32% at 3+ years). For patients <60 years with de novo AML and non-adverse cytogenetics who underwent two-cycle TST, DFS was 67% at 3+ years. However, patients of age equal to 60 years and those with poor-risk disease features still have poor CR and DFS, despite the addition of ATRA.

Ten-day decitabine as initial therapy for newly diagnosed patients with acute myeloid leukemia unfit for intensive chemotherapy.

We retrospectively reviewed outcomes in 45 previously untreated patients with acute myeloid leukemia (AML) considered unfit for chemotherapy who were treated with 10-day courses of decitabine 20 mg/m(2) daily outside of a clinical trial, with no cut-offs for organ function or performance status (PS). Nineteen had Eastern Cooperative Group performance status (ECOG PS) ≥ 2, and 39 had ≥ 2 comorbidities. Fourteen patients (31%) achieved complete remission (CR) and five (11%) CR with incomplete count recovery, for an overall response rate of 42%, after a median of 2 (range, 1-4) courses. The only pretreatment characteristic that differed significantly between responders and non-responders was percent marrow blasts (median 42% vs. 65%; p = 0.01). Median overall survival was 9.0 months; it was 19.4 and 2.3 months for responders and non-responders, respectively (p < 0.001). Thus 10-day decitabine therapy has efficacy in patients with AML considered unfit for chemotherapy, and may serve as a backbone for the addition of other novel agents.

High frequency of rare structural chromosome abnormalities at relapse of cytogenetically normal acute myeloid leukemia with FLT3 internal tandem duplication.

FLT3 internal tandem duplication (ITD) mutations are present in acute myeloid leukemia (AML) in 30% of patients with acute myeloid leukemia (AML), most commonly in those with a normal karyotype, and are associated with short relapse-free survival. Both in vitro and in vivo studies of FLT3-ITD cell lines have demonstrated reactive oxygen species-mediated DNA double-strand breaks and associated error-prone DNA repair as a mechanism of genomic instability, and we hypothesized that genomic instability might be manifested by cytogenetic changes at relapse of FLT3-ITD AML. We retrospectively reviewed charts of patients with cytogenetically normal (CN) FLT3-ITD AML treated at the University of Maryland Greenebaum Cancer Center, with attention to metaphase analysis results at relapse. Cytogenetic data were available from first and, when applicable, subsequent relapses for 15 patients diagnosed with CN FLT3-ITD AML. Among 12 patients with documented FLT3-ITD at first and, when applicable, subsequent relapse, 10 had cytogenetic changes, including nine with rare structural abnormalities. The high frequency of rare structural chromosome abnormalities at relapse in our case series supports a role of genomic instability in the genesis of relapse, and suggests that reactive oxygen species-generating and DNA repair pathways might be therapeutic targets in FLT3-ITD AML.

Tertiary center referral patterns for patients with myelodysplastic syndrome are indicative of age and race disparities: a single-institution experience.

Little is known about disparities in myelodysplastic syndromes (MDS). We performed a retrospective chart review of patients with MDS (n = 252) evaluated at the University of Maryland Greenebaum Cancer Center between 2000 and 2010. The median age at diagnosis was 65 years, which was lower than the median age of 76 years for patients with MDS in the Surveillance, Epidemiology and End Results database. Black males were younger than white males (62 vs. 68 years; p = 0.03) and had longer time to referral (9 vs. 1.5 months; p = 0.03), but black and white females did not differ in age or in time to referral. A difference in World Health Organization subtype classification was noted in black and white patients at diagnosis, but not at referral. There was no difference between all other pretreatment characteristics, treatment and survival by race. Our data suggest barriers to tertiary care referral for older patients and for black males.

Racial differences in presentation, referral and treatment patterns and survival in adult patients with acute myeloid leukemia: a single-institution experience.

BACKGROUND: Disease presentation and outcomes differ by race in a number of malignancies, but data in adult acute myeloid leukemia (AML) are limited. MATERIALS AND METHODS: We conducted a retrospective analysis of pretreatment characteristics, referral and treatment patterns, and outcomes in 548 AML patients evaluated at the University of Maryland Greenebaum Cancer Center, a tertiary care referral center in Baltimore, MD, from 2000 through 2009. Cases were analyzed for time from diagnosis to referral, age, race, gender, socioeconomic status, antecedent hematologic disorder, cytotoxic or radiation therapy for prior malignancy, karyotype, fms-like tyrosine kinase receptor-3 (FLT3) mutations, intensive chemotherapy, clinical trial participation, hematopoietic stem cell transplantation (HSCT) and overall survival (OS). RESULTS: Black patients (n=105) were younger than white patients (n=396) (54 vs. 61 years, p<0.001), were more commonly female (55% vs. 45%, p<0.001), and had a lower estimated median household income ($42,677 vs. $53,534 per year, p<0.001). Black patients more frequently had complex karyotypes (26% vs. 12%, p=0.002) and less frequently normal karyotypes (27% vs. 42%, p=0.02). FLT3 mutation frequency was similar. Time to referral and proportion of patients receiving intensive chemotherapy did not differ, but both clinical trial participation (43% vs. 54%, p=0.04) and HSCT (17% vs. 35% for patients ≤70 years old, p=0.001) were less frequent in blacks than whites. Nevertheless, OS was similar in all black and white patients (median 15 vs. 14 months, p=0.23), and when stratified by age, gender and karyotype risk classification. CONCLUSION: AML presentation and treatment differed in black and white patients, but OS was similar. Black patients appear to have barriers to clinical trial participation and HSCT, and there may be barriers to tertiary care referral for black males.

Subdural hematomas in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia receiving imatinib mesylate in conjunction with systemic and intrathecal chemotherapy.

Imatinib mesylate and other tyrosine kinase inhibitors (TKIs) that inhibit BCR-ABL have had a favorable impact on the treatment of Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). TKIs are generally well tolerated, but they can induce platelet dysfunction, which is of particular concern in the setting of thrombocytopenia in patients with acute leukemia. We present three patients with Ph+ ALL receiving imatinib mesylate in conjunction with systemic and intrathecal chemotherapy who developed subdural hematomas (SDHs). All three were thrombocytopenic and had undergone repeated lumbar punctures for prophylactic intrathecal chemotherapy, but they were not coagulopathic and did not have meningeal leukemia. SDHs occurred in three of a total of 10 adult patients with Ph+ ALL receiving imatinib mesylate in conjunction with systemic and intrathecal chemotherapy at our institution from 2007 to 2010, but in none of 22 adult patients with Ph- ALL receiving the same therapy without imatinib mesylate (p < 0.05). Patients with Ph+ ALL receiving imatinib mesylate, and likely also dasatinib, in conjunction with systemic and intrathecal chemotherapy may be at increased risk of SDH, and should be closely monitored for subtle manifestations of this complication.

Phase 1 and pharmacologic study of MS-275, a histone deacetylase inhibitor, in adults with refractory and relapsed acute leukemias.

MS-275 is a benzamide derivative with potent histone deacetylase (HDAC) inhibitory and antitumor activity in preclinical models. We conducted a phase 1 trial of orally administered MS-275 in 38 adults with advanced acute leukemias. Cohorts of patients were treated with MS-275 initially once weekly x 2, repeated every 4 weeks from 4 to 8 mg/m2, and after 13 patients were treated, once weekly x 4, repeated every 6 weeks from 8 to 10 mg/m2. The maximum-tolerated dose was 8 mg/m2 weekly for 4 weeks every 6 weeks. Dose-limiting toxicities (DLTs) included infections and neurologic toxicity manifesting as unsteady gait and somnolence. Other frequent non-DLTs were fatigue, anorexia, nausea, vomiting, hypoalbuminemia, and hypocalcemia. Treatment with MS-275 induced increase in protein and histone H3/H4 acetylation, p21 expression, and caspase-3 activation in bone marrow mononuclear cells. No responses by classical criteria were seen. Our results show that MS-275 effectively inhibits HDAC in vivo in patients with advanced myeloid leukemias and should be further tested, preferably in patients with less-advanced disease.