Gemtuzumab ozogamicin in acute myeloid leukemia: past, present and future.

After being in the therapeutic wilderness for several decades, acute myeloid leukemia has been recently thrust into the limelight with a series of drug approvals. Technical refinements in production, genetic manipulation and chemical modification of monoclonal antibodies led to growing interest in antibodies-based treatment strategies. Much of the focus of these efforts in acute myeloid leukemia has been on CD33 as a target. On September 2, 2017, the U.S. Food and Drug Administration approved gemtuzumab ozogamicin for treatment of relapsed or refractory CD33+ acute myeloid leukemia. This signals a new chapter in the long and unusual story of gemtuzumab ozogamicin, which was the first antibody-drug conjugate approved for human use by the Food and Drug Administration. In this review we have analyzed the history of this drug which, among several mishaps, is experiencing a second youth and still represents a field to be further explored.

Identification of genomic biomarkers for anthracycline-induced cardiotoxicity in human iPSC-derived cardiomyocytes: an in vitro repeated exposure toxicity approach for safety assessment.

The currently available techniques for the safety evaluation of candidate drugs are usually cost-intensive and time-consuming and are often insufficient to predict human relevant cardiotoxicity. The purpose of this study was to develop an in vitro repeated exposure toxicity methodology allowing the identification of predictive genomics biomarkers of functional relevance for drug-induced cardiotoxicity in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). The hiPSC-CMs were incubated with 156 nM doxorubicin, which is a well-characterized cardiotoxicant, for 2 or 6 days followed by washout of the test compound and further incubation in compound-free culture medium until day 14 after the onset of exposure. An xCELLigence Real-Time Cell Analyser was used to monitor doxorubicin-induced cytotoxicity while also monitoring functional alterations of cardiomyocytes by counting of the beating frequency of cardiomyocytes. Unlike single exposure, repeated doxorubicin exposure resulted in long-term arrhythmic beating in hiPSC-CMs accompanied by significant cytotoxicity. Global gene expression changes were studied using microarrays and bioinformatics tools. Analysis of the transcriptomic data revealed early expression signatures of genes involved in formation of sarcomeric structures, regulation of ion homeostasis and induction of apoptosis. Eighty-four significantly deregulated genes related to cardiac functions, stress and apoptosis were validated using real-time PCR. The expression of the 84 genes was further studied by real-time PCR in hiPSC-CMs incubated with daunorubicin and mitoxantrone, further anthracycline family members that are also known to induce cardiotoxicity. A panel of 35 genes was deregulated by all three anthracycline family members and can therefore be expected to predict the cardiotoxicity of compounds acting by similar mechanisms as doxorubicin, daunorubicin or mitoxantrone. The identified gene panel can be applied in the safety assessment of novel drug candidates as well as available therapeutics to identify compounds that may cause cardiotoxicity.

Immunomodulatory effects of Hedysarum polybotrys extract in mice macrophages, splenocytes and leucopenia.

Astragali Radix (Huang-Qi) is a popular herbal medicine commonly used as a constituent in tonic herbal preparations. Hedysarum polybotrys Handel-Mazzetti is one species used of Astragali Radix. In this study, the immunomodulatory properties of H. polybotrys were explored by LPS-activated and SNP-treated RAW 264.7 cells and splenocytes and, daunoblastina-induced leucopenia BALB/c mice. Formononetin was used as the bioactive marker to monitor the quality of the H. polybotrys extracts. H. polybotrys was extracted with hot-water and methanol, and MeOH extract partitioned with H2O (M-H) and ethyl acetate (M-EA) to yield four different fractions. M-EA had the highest formononetin and total proanthocyanidin content and showed stronger inhibitory effects on the production and expression of NO, PGE2, iNOS and COX-2 in LPS-activated RAW 264.7 cells and splenocytes than the other fractions. In addition, M-EA significantly stimulated the proliferation of LPS-activated RAW 264.7 cells and splenocytes, enhanced NO radicals scavenging and attenuated NO-induced cytotoxicity.  Furthermore, M-EA also significantly increased the rate of recovery of white blood cells level in daunoblastina-induced leucopenia mice. These evidences suggest that this traditional Qi-tonifying herb has potential effects in clinical conditions when immune-enhancing and anti-inflammatory effect is desired.

Administration of chromium(III) and manganese(II) as a potential protective approach against daunorubicin-induced cardiotoxicity: in vitro and in vivo experimental evidence.

Daunorubicin (DNR) is a widely used antitumor drug, but its application is limited because of its cardiotoxic side effects. The present study was designed to investigate the interaction between DNR and cardiac myosin (CM) in the presence of chromium(III) (Cr(3+)) and manganese(II) (Mn(2+)) using fluorescence spectrometry under simulative physiological conditions with the aim of exploring the influence of metal ion on DNR-CM complex and finding out an aggressive approach to abrogate of DNR-induced cardiotoxicity. In detail, the quenching and binding constant of ternary system, including metal ion, DNR, and CM, were measured and compared with the DNR-CM. The data from in vitro experiments indicate that the presence of Cr(3+) or Mn(2+) distinctly decreased the binding force between DNR and CM, and alleviated the cardiac toxicity caused by DNR. In addition, the variations in mice body weight and myocardial enzyme level were examined by in vivo experiments. Animals receiving Cr(3+) or Mn(2+) supplementation of DNR showed preservation of the normal pattern of the heart, especially 2.0 mg Cr(3+)/kg body wt or 50.0 mg Mn(2+)/kg body wt exhibited an obviously protective effect accompanied with body weight raise when compared with the mice treated with DNR alone, decreased the ratio of heart to body weight (BW) and the ratio of left ventricular mass to BW to the normal levels, and inhibited the leak of myocardial enzyme caused by DNR. As a result, this study suggests that pretreatment of lower dose of Cr(3+) (2 mg/kg wt) and moderate dose of Mn(2+) (50 mg/kg wt) might be useful and play an important role in ameliorating the cardiotoxicity of DNR treatment in cancer patients.

Dietary red palm oil protects the heart against the cytotoxic effects of anthracycline.

Strong anti-neoplastic anthracyclines like daunorubicin (DNR) and doxorubicin (DOX) have high efficacy against systemic neoplasm and solid tumours. However, clinically, they cause chronic cardiomyopathy and congestive heart failure. Red palm oil (RPO) supplementation can protect the heart against ischemic injury. We therefore hypothesize that supplementation with RPO during chemotherapy may protect the heart. Control rats received a standard diet, and the experimental group received RPO in addition for 4 weeks. Each group was subsequently injected with either saline or DNR over a 12-day period towards the end of 4 weeks. Hearts were excised and perfused on a working heart system. Functional parameters were measured. Tissue samples were collected for analysis of mRNA and protein levels. DNR + RPO increased aortic output by 25% (p < 0.05) compared with DNR only. Furthermore, DNR treatment significantly reduced tissue mRNA levels of superoxide dismutase 1 (SOD1) and nitric oxide synthase 1 (NOS1) compared with untreated controls. Protein expression of SOD1 followed the same pattern as mRNA levels. NOS1 protein levels were significantly increased in DNR treated rats when compared with untreated controls. In addition, DNR increased phosphorylation of p38 and Jun N-terminal kinase compared with untreated controls, whereas DNR + RPO completely counteracted this activation. DNR + RPO significantly up regulated the protein extracellular signal-regulated kinase 1 level compared with DNR only. In this model of DNR treatment, RPO is associated with stabilization of important antioxidant enzymes such NOS and SOD, and inhibition of the 'stress' induced mitogen-activated protein kinase pathways. Dietary RPO also maintained function, similar to control, in DNR treated hearts.

Effect of naringin on the DNA damage induced by daunorubicin in mouse hepatocytes and cardiocytes.

Naringin (Nar) is a flavonoid that has shown antigenotoxic effect against the chromosome damage induced by various compounds. The aims of the present investigation on Nar were threefold: a) to determine its DNA breaking potential in mouse hepatocytes and cardiocytes, b) to evaluate its capacity to inhibit the DNA damage induced by daunorubicin (Dau) in the same tissues, and c) to determine its capacity to trap free radicals in vitro using the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) method. For the two first purposes we applied the comet assay to three groups of animals administered with Nar by the oral route (50, 250, 500 mg/kg), and made the observations before the chemical administration and at 3, 12, and 21 h postadministration. Other three groups of mice were given equal doses of Nar, and 1 h later they were intraperitoneally injected with 1 mg/kg of Dau. The results showed that Nar did not induce DNA breakage in both types of studied cells, in contrast with the significant damage induced by Dau in hepatocytes and cardiocytes. Moreover, the administration of Nar protected the DNA damage produced by Dau, showing a maximum reduction of 71.3% and 51.1% in hepatocytes and cardiocytes, respectively. With respect to the antioxidant potential, 20 mM of Nar produced a free radical scavenging activity as high as 95%. Our study established a high DNA breaking potential of Dau, and a protective effect by Nar, probably related with its capacity to trap free radicals.

[High risk of cardiac dysfunction after treatment of secondary acute myeloid leukemia following chemotherapy and radiotherapy for breast cancer]. / Risque élevé de dysfonction cardiaque des leucémies aiguës myéloïdes secondaires à un cancer du sein.

Secondary acute myeloid leukaemia (AML) occurring after breast cancer is a rare long-term complication of the chemo- and/or radiation therapy required to treat breast cancer. The usually recognized curative option of these secondary AML includes courses of anthracycline-based chemotherapy followed by haematopoietic stem cell transplantation (HSCT). Cardiac dysfunction during AML treatment of these patients previously treated with anthracyclines for breast cancer has not been reported to date. We evaluated the evolution of cardiac function in seven patients treated with anthracyclines and/or autologous or allogeneic bone marrow transplantation for secondary AML occurring after breast cancer. All of the patients who received a cumulative anthracycline dose above the cardiac toxicity threshold developed cardiac symptoms during AML chemotherapy courses. Moreover, four of the five transplanted patients developed severe heart failure among which two were fatal. Thus, the risk of severe cardiac dysfunction after treatment of secondary AML following breast cancer must be taken in account as part of the therapeutic strategy of those patients. As discussed here, an accurate evaluation of risk factors, the use of sensitive detection tests and of cardioprotective drugs as well as that of non-cardiotoxic chemotherapy might decrease the occurrence and severity of this life-threatening complication.

Anthracycline dose intensification in acute myeloid leukemia.

BACKGROUND: In young adults with acute myeloid leukemia (AML), intensification of the anthracycline dose during induction therapy has improved the rate of complete remission but not of overall survival. We evaluated the use of cytarabine plus either standard-dose or high-dose daunorubicin as induction therapy, followed by intensive consolidation therapy, in inducing complete remission to improve overall survival. METHODS: In this phase 3 randomized trial, we assigned 657 patients between the ages of 17 and 60 years who had untreated AML to receive three once-daily doses of daunorubicin at either the standard dose (45 mg per square meter of body-surface area) or a high dose (90 mg per square meter), combined with seven daily doses of cytarabine (100 mg per square meter) by continuous intravenous infusion. Patients who had a complete remission were offered either allogeneic hematopoietic stem-cell transplantation or high-dose cytarabine, with or without a single dose of the monoclonal antibody gemtuzumab ozogamicin, followed by autologous stem-cell transplantation. The primary end point was overall survival. RESULTS: In the intention-to-treat analysis, high-dose daunorubicin, as compared with a standard dose of the drug, resulted in a higher rate of complete remission (70.6% vs. 57.3%, P<0.001) and improved overall survival (median, 23.7 vs. 15.7 months; P=0.003). The rates of serious adverse events were similar in the two groups. Median follow-up was 25.2 months. CONCLUSIONS: In young adults with AML, intensifying induction therapy with a high daily dose of daunorubicin improved the rate of complete remission and the duration of overall survival, as compared with the standard dose. (ClinicalTrials.gov number, NCT00049517.)

Astragalus membranaceus prevents daunorubicin-induced apoptosis of cultured neonatal cardiomyocytes: role of free radical effect of Astragalus membranaceus on daunorubicin cardiotoxicity.

Anthracyclines are antitumor antibiotics with significant activity against solid and hematologic malignancies. One problem preventing more widespread use has been the development of cardiotoxicity. To determine whether antioxidant agents can reduce the cardiotoxicity of anthracyclines, a herb Astragalus membranaceus was introduced, which has been widely used for the treatment of cardiovascular diseases in China and was confirmed to be an effective antioxidant agent recently. Pre-treatment with Astragalus membranaceus significantly attenuated the daunorubicin-induced increases of reactive oxygen species (p < 0.001), apoptosis (p < 0.05) and the secretions of LDH (p < 0.01) in cultured neonatal cardiomyocytes. Astragalus membranaceus also raised the EC(50) of daunorubicin 1.24-fold. Compared with Astragalus membranaceus, N-acetyl-L-cysteine had similar effects on daunorubicin-induced cell injury, however, superoxide dismutase reduced reactive oxygen species without attenuating apoptosis. The subcellular distribution of DNR was similar to the distribution of MitoTracker Red 580 in mitochondria, which was mainly in the cytoplasm around the nuclear membrane in cultured neonatal cardiomyocytes. In conclusion, the results suggested that Astragalus membranaceus is potentially protective against daunorubicin cardiotoxicity by decreasing free radical release and apoptosis in cultured neonatal cardiomyocytes. The main subcellular distribution of daunorubicin may be in the mitochondria.

Effect of flavonoids on daunorubicin-induced toxicity in H9c2 Cardiomyoblasts.

Daunorubicin (DNR) is one of the most important antitumor agents belonging to the anthracycline group. However, its use is seriously limited by the development of cardiac toxicity. The present study was designed to investigate the effects of quercetin, pycnogenol and naringenin on daunorubicin-induced cytoxicity in H9c2 cells. Protection of H9c2 cardiomyocyte cells was concentration/dose dependent for quercetin > naringenin > pycnogenol = trolox. Quercetin (10(-4)-10(-5) mol/L) after 24 h of co-incubation with DNR significantly increased the cardiomyocyte survival (p < 0.001 and p < 0.05, respectively). A protective effect of other compounds was observed only in the highest concentration/dose used (p < 0.01). After 48 h of incubation quercetin and naringenin significantly decreased daunorubicin-induced cell death at concentrations of 10(-4)-10(-5) mol/L (p < 0.001 and p < 0.01, respectively). The protective effect of pycnogenol and trolox was weaker but significant in the two highest concentrations/doses (p < 0.001 and p < 0.05, respectively). This study also investigated DNR-induced apoptosis and it was shown that both quercetin and naringenin inhibit apoptosis of H9c2 cardiomyocytes cells in vitro. The findings provide evidence that quercetin and naringenin may act as survival factors. The protective effect of flavonoids was compared with that of trolox, a known cardioprotective antioxidant. These results are consistent with the notion that the use of flavonoids may be beneficial in modulating or preventing the cardiotoxicity associated with DNR therapy.

Protective effect of selected flavonoids on in vitro daunorubicin-induced cardiotoxicity.

Flavonoids are an ubiquitous group of polyphenolic substances with varied chemical structures present in foods of plant origin and act as free radical scavenging and chelating agents with a variety of biological activities. Using a model of spontaneously beating, cultured adult rat cardiomyocytes, this study examined the cardioprotective role of quercetin, naringenin, pycnogenol and a model antioxidant, trolox, against daunorubicin-induced toxicity. Cardiomyocyte protection was assessed by MTT test and extracellular lactate dehydrogenase detection. Protection of cardiomyocytes was concentration/dose dependent for quercetin > naringenin > pycnogenol > trolox. Quercetin (10(-4)-10(-6) mol/L) after 24 h of co-incubation with daunorubicin significantly increased the cardiomyocyte survival in all tested concentrations (p < 0.001). The cytoprotective effect of naringenin (10(-4)-10(-6) mol/L) was similar to those of quercetin (p < 0.001 and p < 0.01, respectively). Pycnogenol was the least effective of the flavonoids studied. On the other hand, all tested flavonoids had significantly better protective effects than trolox. The leakage of lactate dehydrogenase induced by daunorubicin was also prevented by the studied compounds and was in accordance with their cytoprotective activity.

[Liposomal daunorubicine combined with cytarabine in the treatment of relapsed/refractory acute myeloid leukemia in children]. / Effektive Rezidivtherapie der akuten myeloischen Leukämie im Kindesalter mit liposomalem Daunorubicin und Cytarabin.

BACKGROUND: First-line treatment in AML commonly included high cumulative doses of anthracyclines with an increasing risk of cardiotoxicity. Liposomal daunorubicin (L-DNR) is thought to be less cardiotoxic without impairment of efficacy. METHODS: The AML-BFM REZ 97 study included two reinduction blocks with L-DNR (2 x 60 mg/m (2) n = 38, since 2/1999 3 x 60 mg/m (2) n = 31) combined with cytarabine (500 mg/m (2) 4 d). Children who achieved a second blast clearance were allocated to allogeneic stem cell transplantation either from a matched related (MRD) or a matched unrelated donor (MUD). Lack of a donor justified haploidentical SCT in early relapse (1st remission < 1 year) and autologous SCT in late relapse. PATIENTS: Between 1/1997 and 9/2001, 69 children were enrolled in the AML-BFM 97 relapse study. The median duration of first remission was 0.9 years. Forty-one patients had a remission of less than one year, 28 of more than a year. RESULTS: 46 children (67 %) achieved a second remission, defined as clearance of blasts in bone marrow and at least a partial hematological reconstitution. Seventeen of these children are alive (12 of 25 children receiving allogeneic SCT (MFD/MUD); 1 of 8 children after haploidentical SCT; 1 of 4 patients after autologous SCT and 3 of 9 patients treated with chemotherapy only). Further three children without 2nd remission survived after MFD-SCT (n = 2) or chemotherapy (n = 1; follow-up 0.3 to 0.7 years). Duration of first remission remains a significant prognostic factor. The pharmacokinetic investigation showed a high overall AUC of 234.6 mg/l h at a dose of 60 mg/m (2), and a volume of distribution of 1.98 l/m (2), which is much lower in comparison to conventional Daunorubicin. Regarding toxicity, the combination of L-DNR and cytarabine followed by SCT was feasible in experienced centers, however, acute complications like infection or septicemia in aplasia, mucositis and GvHD were common. By contrast, no clinical relevant cardiotoxicity was seen so far, but definitive results in long-term cardiotoxicity await a longer follow-up. In conclusion, L-DNR/cytarabine treatment induced a 2nd remission in most of the children with relapsed or refractory AML. It has to be followed by allogeneic SCT which enables long-term survival.

Effects of dietary lipids on daunomycin-induced nephropathy in mice: comparison between cod liver oil and soybean oil.

Although it is well known that dietary lipids affect the course of glomerulonephritis in rats and humans, the precise mechanisms involved have not been fully elucidated. The aim of this study was to investigate the effects of different types of dietary lipids (fish oil and vegetable oil) on daunomycin (DM)-induced nephropathy in mice fed on soybean oil (SO) or cod liver oil (CLO). Urinary protein excretion, serum albumin, creatinine, total cholesterol, and TG were measured, and glomerular histological changes were evaluated. Antioxidant enzymes were also measured, along with the levels of lipid peroxide, GSH, thromboxane (Tx) B2, and 6-keto prostaglandin F1alpha in renal cortical tissue. Dietary CLO significantly reduced urinary albumin excretion and ameliorated the histological changes induced by DM. The increase of tissue lipid peroxide levels seen in SO-fed mice was suppressed in CLO-fed mice, whereas CLO-fed mice showed higher GSH levels than SO-fed mice throughout the experiment. In addition, renal tissue GSH peroxidase activity was significantly higher at 72 h after DM injection in CLO-DM mice than in SO-DM mice. Both renal cortical TxB2 and 6-keto PGF1alpha levels were significantly lower in CLO-DM mice than in SO-DM mice. These results suggest that inhibition of oxidative damage by dietary CLO played an important role in the prevention of DM nephropathy in this mouse model. The effect of CLO was closely associated with the inhibition of Tx synthesis.

Novel SH3 protein encoded by the AF3p21 gene is fused to the mixed lineage leukemia protein in a therapy-related leukemia with t(3;11) (p21;q23).

The mixed lineage leukemia (MLL) gene located at chromosome band 11q23 is frequently rearranged in patients with therapy-related acute monocytic leukemia who received topoisomerase II inhibitors. We have identified a novel fusion partner of MLL (FAB M5b) in a patient who developed t-AML 9 years after treatment for acute lymphoblastic leukemia (ALL). The leukemic cells had a sole karyotypic abnormality of t(3;11) (p21;q23). Screening of a genomic DNA library, prepared from leukemic cell DNA, identified rearranged clones composed of MLL and a novel gene on chromosome 3p21 (AF3p21). The AF3p21 gene encodes a protein of 722 amino acids, which contains an Src homology 3 (SH3) domain, a proline-rich domain, and a bipartite nuclear localizing signal (NLS). RNA analysis demonstrated that exon 6 of the MLL gene fused to exon 2 of the AF3p21 gene. The resulting chimeric protein consists of AT-hooks, methyltransferase, and transcription repressor domains of MLL in addition to the AF3p21 proline-rich domain and NLS but not the AF3p21 SH3 domain.

Neurodevelopmental outcome of infants with acute lymphoblastic leukemia: a Children's Cancer Group report.

BACKGROUND: Infants diagnosed with acute lymphoblastic leukemia (ALL) are considered the patient subgroup at the highest risk for central nervous system (CNS) disease, both at presentation and as an isolated extramedullary relapse. In addition, they are highly vulnerable to adverse developmental sequelae from CNS-directed therapy. METHODS: Thirty patients younger than 12 months at diagnosis (12 males, 18 females) in first hematologic remission were evaluated after completion of ALL therapy (mean age = 62.1 months; standard deviation = 17.2 months; range = 38-102 months). CNS-directed treatment included very high dose infusions of methotrexate (MTX) and intrathecal cytarabine and MTX. Three patients had meningeal leukemia that required additional therapy. Children were administered the McCarthy Scales of Children's Abilities, and parents completed a sociodemographic questionnaire to obtain information about occupation and education. RESULTS: Mean scores on all 6 cognitive and motor indices of the McCarthy Scales were in the average range (Verbal = 52.0; Perceptual = 53.6; Quantitative = 49.6; General Cognitive Index [GCI] = 102.1; Memory = 49.2; Motor = 51.0). Score distributions for each neurodevelopmental index were comparable to age-based population standards. One patient obtained a GCI that exceeded 2 standard deviations above the mean; none scored more than 2 standard deviations below. There was no report of developmental disabilities or neurologic disorders for any of the patients. Risk factors, including age at diagnosis, gender, additional CNS-directed treatment, and family socioeconomic status, were not associated with developmental outcome. CONCLUSIONS: Test findings indicated a generally positive neurodevelopmental outcome for ALL patients diagnosed in infancy who were treated with very high dose MTX as CNS-directed therapy. Combined with the reduction in the isolated CNS relapse rate achieved by the Children's Cancer Group (CCG) clinical trial CCG-107, the results of this study represent a substantial improvement in neurodevelopmental outcome for very young patients compared with infants treated for ALL in the past.

All-trans-retinoic acid in acute promyelocytic leukemia.

BACKGROUND: All-trans-retinoic acid induces complete remission in acute promyelocytic leukemia. However, it is not clear whether induction therapy with all-trans-retinoic acid is superior to chemotherapy alone or whether maintenance treatment with all-trans-retinoic acid improves outcome. METHODS: Three hundred forty-six patients with previously untreated acute promyelocytic leukemia were randomly assigned to receive all-trans-retinoic acid or daunorubicin plus cytarabine as induction treatment. Patients who had a complete remission received consolidation therapy consisting of one cycle of treatment identical to the induction chemotherapy, then high-dose cytarabine plus daunorubicin. Patients still in complete remission after two cycles of consolidation therapy were then randomly assigned to maintenance treatment with all-trans-retinoic acid or to observation. RESULTS: Of the 174 patients treated with chemotherapy, 120 (69 percent) had a complete remission, as did 124 of the 172 (72 percent) given all-trans-retinoic acid (P=0.56). When both induction and maintenance treatments were taken into account, the estimated rates of disease-free survival at one, two, and three years were 77, 61, and 55 percent, respectively, for patients assigned to chemotherapy then all-trans-retinoic acid; 86, 75, and 75 percent for all-trans-retinoic acid then all-trans-retinoic acid; 75, 60, and 60 percent for all-trans-retinoic acid then observation; and 29, 18, and 18 percent for chemotherapy then observation. By intention-to-treat analysis, the rates of overall survival at one, two, and three years after entry into the study were 75, 57, and 50 percent, respectively, among patients assigned to chemotherapy, and 82, 72, and 67 percent among those assigned to all-trans-retinoic acid (P= 0.003). CONCLUSIONS: All-trans-retinoic acid as induction or maintenance treatment improves disease-free and overall survival as compared with chemotherapy alone and should be included in the treatment of acute promyelocytic leukemia.

A discrepancy between the instantaneous and the overall collection efficiency of the Fenwal CS3000 for peripheral blood stem cell apheresis.

The collection efficiency (CE) of the Fenwall CS3000 continuous flow blood cell separator in the apheresis of peripheral blood stem cells during haemopoietic recovery following myelosuppressive chemotherapy was analysed. Ninety-three apheresis were performed in 19 patients using procedure 3 on the Fenwal CS3000. The overall CE was calculated from the pre-apheresis cell counts and the stated blood volume processed. Instantaneous CE was calculated from cell counts in the inlet and return lines. The overall mononuclear cell and granulocyte-macrophage colony forming unit CE were 64.0% and 55.8%, respectively, significantly lower than the instantaneous CEs of 94.5% and 95.4%, respectively (P = 0.0001, t test, for both comparisons). Three factors unrelated to machine performance contributed to the lower overall CE despite a high instantaneous CE: (1) A fall in the patient's mononuclear cell counts during apheresis leading to an overestimation of the cells available for collection, (2) dilution of blood by anti-coagulant, and (3) the operational dead space of the Fenwal CS3000. The overall CE corrected for these 3 factors approximated the instantaneous CE closely. Thus there is little room for further enhancement of machine performance because the Fenwal CS3000 is already operating with a very high instantaneous CE. To achieve major improvement in the yield of peripheral blood stem cell harvests, more effective mobilization protocols and better timing of apheresis are required.

Osseous changes and abnormalities of mineral metabolism in daunomycin rats.

We examined whether daunomycin rats could be used as an experimental model of human chronic renal failure in terms of their osseous changes and mineral metabolism. The daunomycin rats revealed hyperphosphatemia and osteodystrophic bone changes. In this respect, they were similar to human chronic renal failure. A high calcium level was found in the daunomycin rats at first due to the effect of the daunomycin injection, but later there was a lower calcium level than in the control rats due to chronic renal failure. We conclude that daunomycin rats can be successfully used as an experimental model of chronic renal failure from the standpoint of their osseous changes and mineral metabolism.

Idarubicin (4-demethoxydaunorubicin). A preliminary overview of preclinical and clinical studies.

4-Demethoxydaunorubicin (4-DMDR, IMI 30, Idarubicin, NSC 256439) is a new analog of daunorubicin (DNR) with antileukemic activity in experimental systems that is superior to that of daunorubicin (DNR) or doxorubicin (DX). The drug is more potent than DNR and DX and is active by both the intravenous and the oral routes of administration. After i.v. and oral administration in humans, Idarubicin is rapidly metabolized to its 13-dihydroderivative (Idarubicinol) and the plasma levels of this metabolite are consistently higher than those of the unchanged drug. Idarubicinol has been shown to be an active metabolite in experimental models, being as potent and as active as the parent compound. Phase II clinical trials of Idarubicin have indicated that: By I.V. route Idarubicin is a potent antileukemic agent active in relapsed or refractory, ANLL, ALL (adult and pediatric) either as single agent or in combination with Ara-C at doses of 8-12 mg/m2 by i.v. day 1, 2 and 3 or 7-8 mg/m2 i.v. daily X 5 days (adults). There is evidence of lack of cross-resistance with parent drugs and other antileukemic agents. Phase III studies in previously untreated acute leukemias have been initiated. By oral route Idarubicin has antitumor activity in breast cancer at the doses of 35-45 mg/m2 q 3-4 weeks or 15 mg/m2 daily X 3 days q 3-4 weeks. Idarubicin has activity as a single agent in adult leukemias at the doses of 20-30 mg/m2/day X 3 days. The safety of administration (no risk of extravasation), the good tolerability and the reduced potential for cardiac toxicity, make oral Idarubicin particular attractive for further clinical development. Whether Idarubicin proves to be more effective and/or less cardiotoxic in clinical therapy than DNR or DX remains to be seen through prospective randomized studies which have been already initiated both in leukemias and solid tumors.

Anthracycline mechanisms in analogue selection.

Several simple test methods that revealed alterations in mechanisms of action proved to be useful in the selection of three new anthracycline analogues that are currently in preclinical development. 5-Iminodaunorubicin is a quinone-modified analogue, and the resultant suppression of quinone redox cycling appears to correlate with diminished cardiotoxicity rather than with any effect on antitumour activity. N,N-Dibenzyldaunorubicin is an inactive prodrug requiring metabolic activation, a process that appears to give some selectivity of action leading to improved activity. The cyanomorpholino derivative of doxorubicin shows an intense potency against tumours that is not encountered in other closely-related analogues, indicating a highly specific mode of action as yet unidentified. Results with these examples suggest that simple tests related to mechanisms of action may be more useful for analogue selection than extended tests to define antitumour activity.