Erythropoietin use.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to M Keating.
Explore the source record for details and available documents.
Chemotherapy produces extended remissions, and potential cures, in a small minority of patients with acute myeloid leukemia (AML). We explored whether potentially cured patients were at increased risk of subsequent invasive cancer and were able to return to work. Potentially cured patients were defined as those in first or second complete remission (CR) for at least 3 years based on hazard rates for recurrence or death in CR, which declined sharply after this time. Patients who received allogeneic marrow transplant were excluded. We used questionnaires, phone contact, and chart review to obtain information about subsequent cancer and work status. The number of patients who developed invasive cancer was compared with the number expected based on age, gender, and years of follow-up using the Connecticut Tumor Registry. A total of 215 patients met our criteria for potential cure: 203 in first CR and 12 in second CR (of 1,663 treated between 1965 and December, 1992). At a median of 9.2 years from first or second CR, 163 (76%) remain alive in CR. Fifteen patients developed 18 invasive cancers (expected number of patients, 8.8; observed/expected, 1.70; 95% CI, 0.96 to 2.84; P = . 06). Patients initially treated between 1973 to 1979, patients above the potentially cured cohort's median age of 40 years, and those who presented with abnormalities of chromosomes 5 and/or 7 were more likely to develop subsequent cancer, whereas the observed/expected ratio for younger patients was 1.05 (95% CI, 0.13 to 3.80; P = .56). Seventy-four percent of the patients who were working full-time and who were under age 50 at time of treatment for AML have been working full-time in the last 6 months. Only 17 of 56 patients who are currently not working cited physical limitation as the reason. Patients with potentially cured AML are likely to be able to return to work, and at least if younger do not, on average, have an increased risk of invasive cancer.
Recent work has demonstrated that glucocorticoids, nucleoside analogues, and other cancer chemotherapeutics induce apoptosis in chronic lymphocytic leukemia (CLL) cells. In this study, we investigated the involvement of protease activation in these responses using selective peptide inhibitors of the interleukin-1beta converting enzyme (ICE)/caspase family and a Ca2+-activated protease we recently implicated in thymocyte apoptosis. Apoptosis was associated with proteolytic cleavage of poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) and increased caspase protease activity, and cell-permeant caspase antagonists [zVAD(OMe)fmk and Boc-D(OBzl)cmk] blocked apoptosis in response to the glucocorticoid methylprednisolone or the nucleoside analogue fludarabine, indicating that caspase activation was required for these responses. However, a peptide-based inhibitor of the Ca2+-dependent lamin protease (zAPFcmk) also completely suppressed DNA fragmentation and the cleavage of lamin B1 . Strikingly, treatment of cells with zAPFcmk alone led to characteristic PARP cleavage, depletion of the precursor forms of two ICE family proteases (CPP32 and ICH-1), and phosphatidylserine exposure, suggesting that blockade of the lamin protease led to activation of the ICE family. Our results implicate the lamin protease as a target for Ca2+ during chemotherapy-induced apoptosis in CLL lymphocytes, and they identify a novel functional interaction between the protease and members of the ICE family.
In current medical practice, patients with refractory anemia with excess blasts in transformation (RAEB-t), and especially patients with RAEB, receive chemotherapy regimens (AML Rx) administered to patients with acute myeloid leukemia (AML) less often than do patients with AML. These entities are distinguished primarily by marrow blast percentage (5% to 19% RAEB, 20% to 29% RAEB-t, and > or = 30% AML). The poor prognosis of many RAEB or RAEB-t patients, if untreated, led us to give them AML Rx using the same plan as for AML. The purpose of this analysis was to see if diagnosis (RAEB, RAEB-t, or AML) affected outcome. We treated 372 patients with AML (acute promyelocytic leukemia [APL] excluded), 106 with RAEB-t, and 52 with RAEB. AML Rx produced a 62% complete remission (CR) rate in RAEB, essentially identical to the rates in RAEB-t and AML, but event-free survival (EFS) from CR and from start of treatment (start of Rx), as well as overall survival, were poorer in RAEB than in AML or RAEB-t, with AML and RAEB-t being identical. However, patients with RAEB or RAEB-t were more likely to have poor prognostic characteristics, in particular complex abnormalities involving chromosomes 5 and/or 7. Multivariate analyses indicated that, when considered together with cytogenetics and other patient characteristics, a diagnosis of RAEB rather than AML or RAEB-t had no effect on EFS from start of Rx, EFS from CR, survival, or achievement of CR. These analyses suggested a trend for patients with RAEB-t to have better EFS from start of Rx than patients with AML or RAEB (P = .08; relative risk, 0.80; 95% confidence interval, 0.62 to 1.03), but there were no differences with respect to the other outcomes. Our data suggest that the propriety of administering AML Rx to patients with RAEB or RAEB-t who have poor prognosis without treatment is identical to the propriety of treating AML in this fashion. Deterrents to standard AML Rx in these patients could justifiably include cytogenetics, age, etc, but not a diagnosis of RAEB or RAEB-t per se.
Explore the source record for details and available documents.
The immune-mediated graft-versus-leukemia effect is important to prevent relapse after allogeneic progenitor cell transplantation. This process requires engraftment of donor immuno-competent cells. The objective of this study was to assess the feasibility of achieving engraftment of allogeneic peripheral blood or bone marrow progenitor cell after purine analog containing nonmyeloablative chemotherapy. Patients with advanced leukemia or myelodysplastic syndromes (MDS) who were not candidates for a conventional myeloablative therapy because of older age or organ dysfunction were eligible. All patients had an HLA-identical or one-antigen-mismatched related donor. Fifteen patients were treated (13 with acute myeloid leukemia and 2 with MDS). The median age was 59 years (range, 27 to 71 years). Twelve patients were either refractory to therapy or beyond first relapse. Eight patients received fludarabine at 30 mg/m2/d for 4 days with idarubicin at 12 mg/m2/d for 3 days and ara-c at 2 g/m2/d for 4 days (n = 7) or melphalan at 140 mg/m2/d (n = 1). Seven patients received 2-chloro-deoxyadenosine at 12 mg/m2/d for 5 days and ara-C 1 at g/m2/d for 5 days. Thirteen patients received allogeneic peripheral blood stem cells and 1 received bone marrow after chemotherapy. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and methyl-prednisolone. Treatment was generally well tolerated, with only 1 death from multiorgan failure before receiving stem cells. Thirteen patients achieved a neutrophil count of greater than 0.5 x 10(9)/L a median of 10 days postinfusion (range, 8 to 17 days). Ten patients achieved platelet counts of 20 x 10(9)/L a median of 13 days after progenitor cell infusion (range, 7 to 78 days). Eight patients achieved complete remissions (bone marrow blasts were < 5% with neutrophil recovery and platelet transfusion independence) that lasted a median of 60 days posttransplantation (range, 34 to 170+ days). Acute GVHD grade > or = 2 occurred in 3 patients. Chimerism analysis of bone marrow cells in 6 of 8 patients achieving remission showed > or = 90% donor cells between 14 and 30 days postinfusion, and 3 of 4 patients remaining in remission between 60 and 90 days continued to have > or = 80% donor cells. We conclude that purine analog-containing nonmyeloablative regimens allow engraftment of HLA-compatible hematopoietic progenitor cells. This approach permits us to explore the graft-versus-leukemia effect without the toxicity of myeloablative therapy and warrants further study in patients with leukemia who are ineligible for conventional transplantation with myeloablative regimens either because of age or concurrent medical conditions.
OBJECTIVES: We sought to analyze age-gender differences in the rate-corrected QT (QTc) interval in the presence of a QT-prolonging gene. BACKGROUND: Compared with men, women exhibit a longer QTc interval and an increased propensity toward torsade de pointes. In normal subjects, the QTc gender difference reflects QTc interval shortening in men during adolescence. METHODS: QTc intervals were analyzed according to age (< 16 or > or = 16 years) and gender in 460 genotyped blood relatives from families with long QT syndrome linked to chromosome 11p (KVLQT1; n = 199), 7q (HERG; n = 208) or 3p (SCN5A; n = 53). RESULTS: The mean QTc interval in genotype-negative blood relatives (n = 240) was shortest in men, but similar among women, boys and girls. For genotype-positive blood relatives, men exhibited the shortest mean QTc interval in chromosome 7q- and 11p-linked blood relatives (n = 194), but not in the smaller 3p-linked group (n = 26). Among pooled 7q- and 11p-linked blood relatives, multiple regression analysis identified both genotype (p < 0.001) and age-gender group (men vs. women/children; p < 0.001) as significant predictors of the QTc interval; and heart rate (p < 0.001), genotype (p < 0.001) and age-gender group (p = 0.01) as significant predictors of the absolute QT interval. A shorter mean QT interval in men was most evident for heart rates < 60 beats/min. CONCLUSIONS: In familial long QT syndrome linked to either chromosome 7q or 11p, men exhibit shorter mean QTc values than both women and children, for both genotype-positive and -negative blood relatives. Thus, adult gender differences in propensity toward torsade de pointes may reflect the relatively greater presence in men of a factor that blunts QT prolongation responses, especially at slow heart rates.
New treatments which may change the course of a disease, or which have potential carcinogenicity, may result in the development of new cytogenetic or clinical disorders. Three patients with Philadelphia chromosome-positive (Ph-positive) chronic myeloid leukemia (CML) who developed new cytogenetic abnormalities after achieving a cytogenetic complete remission (CR) of their Ph-positive disease with interferon alpha (IFN-alpha) based therapy are described. Patient 1 developed chromosomal abnormalities involving chromosomes 5 (5q13-34) and later 7 (monosomy 7) 60 months after the start of therapy and 20 months after IFN-alpha was discontinued. A myelodysplastic syndrome was noted 83 months from the start of therapy. Patient 2 developed a myeloproliferative syndrome with 18p11 chromosomal abnormalities 90 months after the start of the therapy and 60 months after IFN-alpha was discontinued. Patient 3 developed a chromosome 11 abnormality (11q21-23) 23 months after the start of therapy, without hematological manifestations. All three patients remain in cytogenetic CR of Ph-positive disease with the hypermetaphase fluorescent in situ hybridization and polymerase chain reaction studies for BCR/ABL showing minimal residual disease. The emergence of new cytogenetic or clinical disorders in patients with CML on IFN-alpha therapy needs to be monitored. These findings may be related to changing the natural course of CML, to therapy, or to the emergence of suppressed clones in a stem cell disorder.
In vitro studies suggest that nucleoside analogs have an antileukemic effect against chronic myelogenous leukemia (CML). We investigated the antileukemia effect of deoxycoformycin (DCF) and fludarabine in patients with CML. Four patients with Philadelphia chromosome (Ph)-positive CML were treated with DCF at 4 mg/m2 every week for 4 weeks, then every other week for four doses, and then every month as maintenance. Two patients were in late chronic phase and two in accelerated phase. All had previously failed therapy with interferon-alpha (IFN-A). Nine patients were treated with fludarabine 30 mg/m2/day for 5 days every 28 days. Three had Ph-positive CML, and six Ph-negative disease. Five patients were in accelerated phase and four in late chronic phase. Three patients treated with DCF had normalization of WBC counts while on the weekly schedule but progressed when changed to every other week. The fourth patient had no objective response. There were no cytogenetic responses. DCF was well tolerated with only mild nausea and vomiting in all patients. Patients treated with fludarabine received a median of two courses (range 1-4). In two patients (both Ph-positive), disease progressed to blastic phase upon recovery. Two other patients died of hemorrhagic complications secondary to thrombocytopenia. In all other cases fludarabine produced a transient reduction of WBC counts, but counts recovered to levels equal to or greater than the pre-treatment values. There were no cytogenetic responses. These results, together with previous experience with 2-CDA producing only hematologic responses, suggest that nucleoside analogs may not have a significant role in the management of CML.
Retinoids have significant antiproliferative effect against chronic myelogenous leukemia (CML) cells in vitro. We conducted a pilot study to investigate the clinical effect of all-trans retinoic acid (ATRA) in patients with CML. Thirteen patients with Philadelphia chromosome (Ph)-positive CML in late chronic phase (n=7), accelerated phase (n=5), or blastic phase (n=1) were treated. All had been previously treated and 12 (92%) had disease refractory to interferon-alpha therapy. They received ATRA 175 mg/m2 orally in two divided doses daily until disease progression. The median duration of therapy was 56 days (range 11 to 190). Only one patient in late chronic phase had a transient decrease in WBC counts; all other patients in late chronic phase showed no response to therapy. Four of the five patients in accelerated phase showed evidence of antileukemia effect manifested by a decrease in bone marrow and/or peripheral blood blasts, promyelocyte and/or basophil percentages. In all cases the response was transient. The patient in blastic phase had no evidence of antileukemic effect. The treatment was well tolerated with the major side-effects being headache, nausea, dry skin, and dry mucosal membranes. One patient required dose reductions due to toxicity. We conclude that in this population of patients with extensively treated, advanced stage, Ph-positive CML, ATRA alone is ineffective for long-term therapy. The antileukemia effect seen in some patients warrants further investigation of retinoids in other schedules and in combinations in patients with CML.
Philadelphia chromosome (Ph)-positive acute lymphocytic leukemia (ALL) constitutes 15-35% of all ALL in adults. Its detection is prognostically significant. The Ph abnormality is usually detected through standard cytogenetic analysis but 20-30% of patients have insufficient metaphases (IM) with such analysis. To detect the BCR-ABL oncoprotein in peripheral blood specimen of patients with ALL at the time of diagnosis and at follow-up, a new sensitive technique of enhanced chemiluminescence Western blot (ECL-WB) analysis was investigated. Among 41 patients with newly diagnosed ALL, nine were Ph positive by cytogenetic studies; they were also BCR-ABL positive according to ECL-WB. Eight had p190 disease, and one had p210 disease. Among the 16 patients with IM, none demonstrated the oncoprotein through ECL-WB or through simultaneous Southern blot (SB) for p210 rearrangement. Follow-up studies were available for seven patients: four had detectable protein and three of them relapsed 4-20 weeks later; three had undetectable protein and one of them (who had low level protein at the time of diagnosis) relapsed 11 weeks later. Although none of the patients with IM at diagnosis had detectable protein according to ECL-WB, this was probably due to the small number of patients studied. One patient with IM studied at follow-up demonstrated the protein by ECL-WB. In summary, we describe a technique that is useful in the detection of p190/p210 ALL at diagnosis. It is less time consuming, and more cost effective than standard chromosome banding techniques. It may also detect the oncoprotein in cases with IM. Although a larger number of patients should be studied to prove its clinical usefulness, this technique may also be of value for monitoring residual disease at follow-up.
We had observed that several patients with acute promyelocytic leukemia (APL) were markedly obese. Therefore we determined the relationship between obesity and a diagnosis of APL among patients with acute myelocytic leukemia (AML). Between 1980 and 1995 we saw 1245 patients with newly-diagnosed AML of whom 120 had APL. Increasing body mass index (BMI) was strongly associated with a diagnosis of APL (P=0.0003). Like Douer et al (Blood 1996; 8: 303-313) we found APL to be more frequent in Latinos and younger patients (P < 10[-4] for both). Logistic regression indicated that increasing BMI, decreasing age, and Latino origin were each independently associated with a diagnosis of APL (multivariate P values <10[-4], <10[-4], 0.0035, respectively). Since the mean BMI in the non-APL patients (25.1) resembled that of the general US population, it appears that APL patients are 'heavy' and not that non-APL patients are 'thin'. Five of the APL patients (4.2%) had a BMI >50 (vs none of the other 1125 AML patients). Given the distribution of BMI in the general US population ages 17-74, the probability that five of 120 normal adults would have a BMI >50 is virtually nil. Excluding the five very heavy APL patients does not alter the conclusion that increasing BMI predicted for APL in patients with AML. Although the mechanism is unclear there appears to be an association between increasing BMI and a diagnosis of APL among patients with AML. There may also be an association between APL and obesity.
The aim of the study was to evaluate the activity of decitabine, a hypomethylating agent, in the treatment of patients with chronic myelogenous leukemia (CML) in transformation. Thirty-seven patients with CML in blastic (20 patients) or accelerated phases (17 patients) were treated. Their median age was 52 years; 36 had Philadelphia chromosome-positive disease. Decitabine was given at 100 mg/m2 over 6 h every 12 h x 10 doses (1000 mg/m2) to 13 patients, and at 75 mg/m2 over 6 h every 12 h x 10 doses (750 mg/m2) to 24 patients. In blastic phase, two patients (10%) achieved a complete hematologic response (one with Ph suppression), and three (15%) had a hematologic improvement (marrow CR, platelets <100 x 10[3]/microl), for an overall response rate of 25%. In accelerated phase, six patients (35%) returned to a second chronic phase (two with Ph suppression), one (6%) had a hematologic improvement, and two (12%) had a partial hematologic response, for an overall response rate of 53%. Prolonged myelosuppression was the most significant side-effect. The median time to recovery of granulocytes above 500/microl was 48 days, and to recovery of platelets above 30 x 10(3)/microl, 31 days. Febrile episodes occurred in 25 patients (68%) including documented infections in 17 patients (46%). Decitabine has promising activity in CML. The most significant side-effect is prolonged myelosuppression. Decitabine may show activity in other myeloid disorders such as acute myeloid leukemia and myelodysplastic syndrome, as well as in other hematologic malignancies, alone or with other drug combinations. Its value in the context of stem cell support should also be investigated.
Sixty-six adults with refractory acute lymphocytic leukemia received salvage therapy with the 'hyper-CVAD' regimen, consisting of eight courses of alternating intensive chemotherapy with growth factor support, followed by oral maintenance chemotherapy. Their outcome was compared with 63 prognostically similar historical control patients treated with high-dose Ara-C plus mitoxantrone with or without GM-CSF. Overall, the complete response rates were similar in the treatment and control groups (29 of 66 (44%) vs 24 of 63 (38%)). There were more patients in the current study with primary resistant disease (10 of 66 (15%) vs one of 63 (2%), P = 0.006), and conversely fewer patients with secondary resistance (19 of 66 (29%) vs 28 of 63 (44%), P = 0.06). Recovery of granulocyte counts above 500/microl was significantly faster in the current study when compared to high-dose Ara-C-treated patients who were given GM-CSF (20 vs 25 days, P = 0.04). Survival was prolonged in the hyper-CVAD-treated patients, with most of the benefit seen in first salvage patients (42 vs 20 weeks, P = 0.016). When only first salvage patients were considered, there was a significant difference in disease-free survival in favor of hyper-CVAD (52 vs 20 weeks, P = 0.008). The hyper-CVAD regimen is a more effective and less toxic salvage regimen for relapsed acute lymphocytic leukemia than high-dose Ara-C-based regimens.
We searched for novel imprinted genes in a region of human chromosome 11p15.5, which contains several known imprinted genes. Here we describe the cloning and characterization of the IPL ( I mprinted in P lacenta and L iver) gene, which shows tissue-specific expression and functional imprinting, with the maternal allele active and the paternal allele relatively inactive, in many human and mouse tissues. Human IPL is highly expressed in placenta and shows low but detectable expression in fetal and adult liver and lung. Mouse Ipl maps to the region of chromosome 7 which is syntenic with human 11p15.5 and this gene is expressed in placenta and at higher levels in extraembryonic membranes (yolk sac), fetal liver and adult kidney. Mouse and human IPL show sequence similarity to TDAG51 , a gene which was shown to be essential for Fas expression and susceptibility to apoptosis in a T lymphocyte cell line. Like several other imprinted genes, mouse and human IPL genes are small and contain small introns. These data expand the repertoire of known imprinted genes and will be helpful in testing the mechanism of genomic imprinting and the role of imprinted genes in growth regulation.
OBJECTIVES: To determine if the rate of change in forced expiratory volume in one second (FEV1) in subjects with high exposure to Latrobe Valley brown coal dust was significantly greater than the rate of change among subjects with low exposure. METHODS: A retrospective dynamic cohort design with variable time windows. This study was conducted over a period of 14 years from 1980 to 1994 and used data collected by the State Electricity Commission (SEC) Lung Function Unit for an asbestos surveillance programme. The subjects were exposed to low, medium, or high levels of coal dust. Basic spirometry with wedge bellows spirometers was used to assess lung function. A general linear model (GLM) was used to assess the effects of smoking and exposure to coal dust upon the change in forced expiratory volume in one second (FEV1) while adjusting for age and height. RESULTS: The mean (95% confidence interval (95% CI) rate of decline in FEV1 was 40 (36 to 44) ml/year. Age was a significant predictor of change. A significant effect was found for smoking (P = 0.02) and for exposure to coal dust (P = 0.008). The only significant difference with exposure to coal dust was between the high and mixed exposure categories. CONCLUSION: There is no convincing evidence of excessive decline in FEV1 with exposure to coal dust > 0.75 mg/m3. The absence of a dose response relation provides some evidence against a causal relation. On the basis of this study, reduction of the exposure standards currently applied to brown coal dust in the Victorian electricity industry is not warranted to prevent respiratory disease.
PURPOSE: To determine the effect of omission of cytarabine (ara-C) from treatment of newly diagnosed acute promyelocytic leukemia (APL), which allows administration of more anthracycline. PATIENTS AND METHODS: Induction consisted of all-trans retinoic acid (ATRA) 45 mg/m2 daily until complete remission (CR) and idarubicin 12 mg/m2 daily for 4 days beginning on day 5 of ATRA. Patients in CR received two courses of idarubicin 12 mg/m2 daily for 3 days and then, until 2 years post-CR date, alternated three cycles of mercaptopurine, vincristine, methotrexate, and prednisone (POMP) with one cycle of idarubicin 12 mg/m2 daily for 2 days. Results in the 43 patients treated (41 with t(15;17) on standard or Southern analysis) were compared with those in 57 historic newly diagnosed APL patients given ara-C with either doxorubicin, amsacrine (AMSA), or daunorubicin without ATRA, using logistic and Cox regression to assess effects of non-treatment-related covariates on patient outcomes. RESULTS: The CR rate in the current group was 77% (95% confidence interval [CI], 62% to 88%) and was not significantly different from the historic rate. In contrast, disease-free survival (DFS) in CR is superior in the current group (probability at 1 year 0.87; 95% CI, 0.73 to 1.0). This has translated into superior overall DFS for the current group (P = .03 adjusting for the predictive covariates initial WBC and platelet count; 1-year DFS probability 0.67; 95% CI, 0.52 to 0.82; median follow-up 102 weeks). The current treatment appears better both in patients with and without t(15; 17) on standard cytogenetic analysis. CONCLUSION: Given the difficulties inherent in comparing sequential studies and recognizing the multiple differences in treatment between current and historic groups, our results suggest that a large randomized trial incorporating use of ATRA should assess the utility of omitting ara-C from treatment of newly diagnosed APL, thus allowing delivery of more anthracycline.
PURPOSE: Expression of the multidrug resistance gene (MDR1) p170 protein is frequent in leukemic blasts from patients with relapsed acute myelogenous leukemia (AML). A phase I study using the nonimmunosuppressive MDR1 blocker SDZ PSC-833 (PSC) in combination with mitoxantrone (MITO) and etoposide (VP) was performed. PATIENTS AND METHODS: Starting doses (LVL0) of MITO (3.25 mg/m2/d on days 1 and 3 to 6) and VP (210 mg/m2/d on days 1 and 3 to 5) were 40% of the maximal-tolerated dose (MTD) from a prior study. A 1.5-mg/kg loading dose of PSC was followed by a 120-hour continuous infusion of 10 mg/kg/d on days 2 to 6. Blood samples for PSC, MITO, and VP pharmacokinetics (PK) were taken on days 1 and 3, and samples for MDR1 expression were taken on day 0. RESULTS: Severe mucositis developed in all patients at LVL0; therefore, MITO and VP doses were reduced to 2.5 and 170 mg/m2 (LVL-1) for the next seven patients, and this dose proved to be MTD. All LVL0 and three LVL-1 patients had transient elevations in the serum bilirubin level to > or = 4 mg/dL. Serum creatinine level increased to greater than 2 mg/dL in one case. There were no other grade 3 or 4 nonhematologic toxicities observed. The peripheral blood was cleared of leukemia in three LVL0 and four LVL-1 patients. The marrow was cleared of leukemic cells in one LVL0 and five LVL-1 patients, and a significant reduction in marrow leukemic infiltrate was observed in eight of 10. No patient achieved complete remission (CR), and all died of progressive disease (n = 8) or infection (n = 2). MDR1 expression was detected by fluorescent-activated cell sorter (FACS) analysis in five of seven cases. An elevated MDR1 mRNA level was detected by quantitative polymerase chain reaction (Q-PCR) in six of eight cases studied. Clearing of leukemia cells from the marrow occurred in four of six MDR1-positive and one of three MDR1-negative patients. Despite the fact that LVL0 doses had to be reduced due to toxicity, coadministration of PSC did not produce a consistent effect on MITO PK; however, it did repeatedly lead to increased levels of VP in the serum. CONCLUSION: We conclude that PSC-MITO-VP is a tolerable regimen with antileukemic activity. Addition of PSC necessitated a 66% reduction in MITO and VP doses from a prior study without PSC.