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PubMed1993

Activity of topoisomerase inhibitors against Pneumocystis carinii in vitro and in an inoculated mouse model.

Five topoisomerase II inhibitors (amsacrine [m-AMSA], two epipodophyllotoxins, and two quinolones) and the alkaloid camptothecin (a topoisomerase I inhibitor) were evaluated to assess their activities against Pneumocystis carinii. In vitro, both etoposide (VP-16) and teniposide (VM-26) at 1 microgram/ml suppressed P. carinii growth. Amsacrine was toxic to P. carinii and to the feeder cells in vitro. Camptothecin suppressed the growth of P. carinii in vitro only at 100 micrograms/ml. Studies in immunosuppressed mice demonstrated the efficacy of teniposide against P. carinii pneumonia, but successful administration of teniposide was schedule dependent with significant toxicity at therapeutic dosages.

Animals↗
PubMed1992

Clinical pharmacology and schedule dependency of the podophyllotoxin derivatives.

Etoposide and teniposide are closely related derivatives of podophyllotoxin, and both have a phase-specific action in the late S and early G2 phases of the cell cycle. Etoposide has attracted more widespread use and study, although no evidence suggests a differing mode of action or spectrum of anticancer activity. The drugs have significant differences in their clinical pharmacology, however. Teniposide exhibits greater protein-binding affinity, has a longer plasma terminal elimination half-life, and has reduced plasma and renal clearances. Little is accurately known about the metabolism of either drug, but the fact that 40% to 60% of administered etoposide is accounted for by excretion or metabolism, whereas the range is only 10% to 25% for teniposide, reflects a further difference between the drugs. Renal dysfunction impairs etoposide excretion, but the effect of hepatic impairment on drug clearance is unclear. A specific oral formulation exists only for etoposide, although the unpalatable intravenous preparations of both drugs can be taken orally. The bioavailability of oral etoposide is about 50% at doses of 200 mg or less and decreases as drug doses increase. There is considerable intrapatient and interpatient variation in etoposide absorption, but the reasons for this are unknown. In vitro, the efficacy of etoposide is highly dependent on the schedule of administration. The superior efficacy without increased toxicity of more prolonged schedules of etoposide administration has been demonstrated recently in patients with small cell lung cancer (SCLC). Although the optimal schedule in any specific tumor is not known, current pharmacodynamic evidence suggests that the efficacy of etoposide, at least in SCLC, is related to the maintenance of prolonged low blood concentrations of drug.

Chemical Phenomena↗
PubMed2005

[Treatment of refractory and relapsed acute lymphocytic leukemia in adults].

OBJECTIVE: To analyze on the efficacy and toxicity of fludarabine and teniposide + mitoxantrone (MIT) regimens on treating refractory and relapsed acute lymphocytic leukemia in adult patients. METHODS: Teniposide 100 mg/d, 5-7 d, MIT 10 mg/d, 2 d and fludarabine regimens [Flu 30 mg/(m(2) . d), 3- 5 d, Cytarabine (Ara-c )1-2 g/(m(2) . d), 5 d; Flu 50 mg/d, 5 d, Ara-c 200 mg/d, 5 d, MIT 4 mg/d, 4 d] were used to treat 42 cases of adults with refractory and relapsed acute lymphocytic leukemia(ALL). G-CSF 5 microg/(kg . d) were used when WBC<1.0 x 10(9)/L. RESULTS: In both the regimens fludarabine and VM (teniposide + MIT), the complete remission (CR) rate was 45% versus 31.8% (P>0.05); the median neutropenia began 6 days after the regimens arresting and lasting 10 versus 7.5 days, P>0.05; thrombocytopenia begin at time of 10 versus 6.5 days (P<0.05) after the regimens arresting and lasting 6 versus 10 days (P>0.05). Fludarabine regimen had less non-haematological toxic effect than that of VM. CONCLUSION: Compared with VM, Fludarabine regimen was a very effective alternative treatment for CR induction in adult patients with refractory and relapsed ALL and low toxicity.

Adolescent↗
PubMed1990

Quantitative adaptation of the bacteriophage P4 DNA unknotting assay for use in the biochemical and pharmacological characterization of topoisomerase II.

The ATP-dependent unknotting of phage P4 DNA is a highly specific assay for type II topoisomerases. Despite the unique specificity of the assay, however, its semiquantitative design has limited its use in studying the biochemical properties of these enzymes. To overcome this problem, we have modified the P4 DNA unknotting assay to provide a sensitive and reproducible method for quantifying topoisomerase II activity. Methods are described for accurate measurement of 10-100 ng of unknotted P4 DNA. Under the assay conditions employed, the initial rate of topoisomerase II activity was linear through 30 min. The quantitative assay has been used to determine biochemical and pharmacological parameters of purified topoisomerase II (p170). No topoisomerase II activity was observed in the absence of ATP; enzymatic activity was optimal between 0.5 and 1.0 mM ATP, but substrate inhibition occurred at concentrations above 1 mM. Eadie-Hofstee analysis with varying ATP concentrations gave an apparent Km for ATP of 0.24 mM and a maximal velocity under these conditions of 7.4 ng P4 DNA unknotted/min/ng topoisomerase II. IC50 values were determined for several topoisomerase inhibitors, including amsacrine, teniposide, and novobiocin. Inhibition by teniposide was found to be uncompetitive versus ATP, with a Ki of 3.7 microM. In contrast, inhibition by novobiocin was competitive versus ATP, indicating that teniposide and novobiocin inhibit topoisomerase II by different mechanisms.

Amsacrine↗
PubMedDate not supplied

Effects of VM-26 and lonidamine on a B16 melanoma cell line.

The treatment of exponentially-growing B16 melanoma cells with teniposide causes a dose- and time-dependent decrease of cell survival. By means of the nucleoid technique, the formation of double strand breaks was demonstrated in the nuclei of the treated cells, indicating a possible involvement of topoisomerase II. DNA double strand breaks were rapidly but ineffectively repaired. Morphometric and densitometric analyses showed that teniposide treatment causes a considerable increase of nuclear area, nuclear DNA and cell size, associated with a lowering of the mitotic index to less than one hundredth of that of the controls. The cytocidal effect of VM-26 can be potentiated by the addition of a non-lethal dose of lonidamine, whose synergism is particularly evident at low teniposide concentrations.

Animals↗
PubMed1985

Serum protein reduction of the enhancement of methotrexate accumulation by vincristine and 4'-demethylepipodophyllotoxin in the Ehrlich ascites tumor cell in vitro.

The Vinca alkaloid vincristine and the epipodophyllotoxin derivative teniposide significantly elevate steady state levels of methotrexate in the Ehrlich ascites tumor cell in vitro. However, the presence of circulating serum proteins compromises this drug-cell interaction. In the presence of bovine serum albumin, elevation of cellular methotrexate levels by vincristine and teniposide in vitro is reduced by 60-70%. In the presence of physiological concentrations of human serum albumin and human serum glycoproteins, the enhancement of cellular methotrexate accumulation by vincristine is reduced by approximately 50% while enhancement of cellular methotrexate accumulation by teniposide is essentially eliminated. These findings may in part explain the observations that vincristine does not alter the cellular pharmacokinetics of methotrexate in vivo and may provide a rationale for the lack of therapeutic synergism between vincristine and methotrexate when the Vinca alkaloid is administered concurrent with or prior to the antifolate compound in the tumor bearing animal. Furthermore these studies indicate the difficulties inherent in attempting to extrapolate from in vitro studies of drug-cell interaction to the intact animal.

Animals↗
PubMed2001

Paclitaxel: a pharmacoeconomic review of its use in non-small cell lung cancer.

UNLABELLED: A number of first-line chemotherapy options for patients with advanced non-small cell lung cancer (NSCLC) are advocated in treatment guidelines and/or by various clinical investigators. Platinum-based chemotherapy has clearly demonstrated efficacy in patients with advanced NSCLC and is generally recommended as first-line therapy, although there is increasing interest in the use of non-platinum chemotherapy regimens. Among the platinum-based combinations currently used in clinical practice are regimens such as cisplatin or carboplatin combined with paclitaxel, vinorelbine, gemcitabine, docetaxel or irinotecan. The particular combinations employed may vary between institutions and geographical regions. Several pharmacoeconomic analyses have been conducted on paclitaxel in NSCLC and most have focused on its use in combination with cisplatin. In terms of clinical efficacy, paclitaxel-cisplatin combinations achieved significantly higher response rates than teniposide plus cisplatin or etoposide plus cisplatin (previously thought to be among the more effective regimens available) in two large randomised trials. One of these studies showed a survival advantage for paclitaxel plus cisplatin [with or without a granulocyte colony-stimulating factor (G-CSF)] compared with etoposide plus cisplatin. A Canadian cost-effectiveness analysis incorporated data from one of the large randomised comparative trials and showed that the incremental cost per life-year saved for outpatient administration of paclitaxel plus cisplatin versus etoposide plus cisplatin was $US 22181 (30619 Canadian dollars; $Can) [1997 costs]. A European analysis incorporated data from the other large randomised study and showed slightly higher costs per responder for paclitaxel plus cisplatin than for teniposide plus cisplatin in The Netherlands ($US 30769 vs $US 29592) and Spain ($US 19 923 vs $US 19724) but lower costs per responder in Belgium ($US 22852 vs $US 25000) and France ($US28 080 vs $US 34747) [1995/96 costs]. In other cost-effectiveness analyses, paclitaxel plus cisplatin was associated with a cost per life-year saved relative to best supportive care of approximately $US 10000 in a US study (year of costing not reported) or $US 11200 in a Canadian analysis ($Can 15400; 1995 costs). Results were less favourable when combining paclitaxel with carboplatin instead of cisplatin and particularly when G-CSF was added to paclitaxel plus cisplatin. The Canadian study incorporated the concept of extended dominance in a threshold analysis and ranked paclitaxel plus cisplatin first among several comparator regimens (including vinorelbine plus cisplatin) when the threshold level was $Can 75000 ($US 54526) per life-year saved or per quality-adjusted life-year gained (1995 values). CONCLUSION: Current treatment guidelines for advanced NSCLC recognise paclitaxel-platinum combinations as one of the first-line chemotherapy treatment options. In two large head-to-head comparative clinical trials, paclitaxel plus cisplatin was associated with significantly greater response rates than cisplatin in combination with either teniposide or etoposide, and a survival advantage was shown for paclitaxel plus cisplatin (with or without G-CSF) over etoposide plus cisplatin. There are limitations to the currently available pharmacoeconomic data and further economic analyses of paclitaxel-carboplatin regimens are warranted, as this combination is widely used in NSCLC and appears to have some clinical advantages over paclitaxel plus cisplatin in terms of ease of administration and tolerability profile. Nevertheless, results of various cost-effectiveness studies support the use of paclitaxel-platinum combinations, particularly paclitaxel plus cisplatin, as a first-line chemotherapy treatment option in patients with advanced NSCLC.

Antineoplastic Agents, Phytogenic↗
PubMed1987

Relationship between the intracellular effects of camptothecin and the inhibition of DNA topoisomerase I in cultured L1210 cells.

Results of filter elution assays of lesions produced in the DNA of cultured L1210 cells by the antineoplastic alkaloid camptothecin support the notion that topoisomerase I is an intracellular target of this drug. One to 10 microM camptothecin induced DNA single-strand, but not double-strand, breaks when incubated with intact cells or with their isolated nuclei. Approximately one half of the strand breakage was protein concealed, as judged by filter elution. Camptothecin-induced, protein-concealed DNA strand breaks disappeared rapidly after drug removal. DNA-protein cross-links were generated by camptothecin with frequencies approximately equal to those of protein-concealed DNA strand breaks. It is likely that camptothecin can inhibit topoisomerase I in intact cells in a manner similar to that in which other antineoplastic agents such as amsacrine or teniposide inhibit topoisomerase II. DNA-breaking lesions other than those resulting from trapped topoisomerase I-DNA complexes may also be generated by camptothecin. The yields of DNA strand breaks induced by camptothecin, amsacrine, or teniposide were approximately doubled when cells were incubated for 16 h with 3-aminobenzamide, an inhibitor of poly(ADP ribosylation) of proteins, prior to 1-h exposure to the antineoplastic compounds. 3-Aminobenzamide also enhanced the cytotoxic action of camptothecin, amsacrine, and teniposide. These results suggest that protein-concealed strand breaks can be lethal lesions and that intracellular topoisomerase I and II activity may be regulated coordinately through poly(ADP ribosylation).

Animals↗
PubMed1993

Single-strand conformational polymorphism analysis of the M(r) 170,000 isozyme of DNA topoisomerase II in human tumor cells.

Five cell lines selected for resistance to the cytotoxicity of inhibitors of DNA topoisomerase II have point mutations in the gene that codes for the M(r) 170,000 form of this enzyme. In each case, the mutation results in an amino acid change in or near an ATP binding sequence of the M(r) 170,000 isozyme of topoisomerase II. We used single-strand conformational polymorphism analysis to screen for similar mutations in other drug-resistant cell lines or in leukemic cells from patients previously treated with etoposide or teniposide. We also analyzed the region of the gene that codes for amino acids adjacent to the tyrosine at position 804 of topoisomerase II which binds covalently to DNA. CEM/VM-1, CEM/VM-1-5, and HL-60/AMSA human leukemic cell lines were used as controls; 3 of 3 known mutations were detected by migration differences of polymerase chain reaction products from the RNA extracted from these three lines. A previously unknown mutation was found in the tyrosine 804 region of the M(r) 170,000 topoisomerase II expressed by CEM/VM-1 and CEM/VM-1-5 cells. Sequence analysis showed that substitution of a T for a C at nucleotide 2404 resulted in an amino acid change of a serine for a proline at amino acid 802. No mutations in any of the ATP binding sequences or in the tyrosine 804 region were detected in polymerase chain reaction products from RNA extracted from human leukemia HL-60/MX2 or CEM/MX1 cells (both cell lines selected for resistance to mitoxantrone) or in human myeloma 8226/Dox1V cells (selected for resistance by simultaneous exposure to doxorubicin and verapamil). No mutations were detected in polymerase chain reaction products from RNA extracted from blasts of 15 patients with relapsed acute lymphocytic leukemia, previously treated with etoposide or teniposide. We conclude that: (a) single-strand conformational polymorphism analysis is useful for screening for mutations in topoisomerase II; (b) resistance to the cytotoxicity of inhibitors of DNA topoisomerase II is not always associated with mutations in ATP binding sequences or the active site tyrosine region of M(r) 170,000 topoisomerase II; and (c) mutations similar to those detected in drug resistant cells selected in culture have not been identified in blast cells from patients with relapsed acute lymphocytic leukemia, previously treated with etoposide or teniposide.

Adenosine Triphosphate↗
PubMed2000

Alternating drug pairs with or without periodic reinduction in children with acute lymphoblastic leukemia in second bone marrow remission: a Pediatric Oncology Group Study.

BACKGROUND: Children with acute lymphoblastic leukemia (ALL) who experience hematologic recurrence while receiving chemotherapy or within 6 months after its cessation have a low cure rate. In this study (Pediatric Oncology Group Protocol 8303) two methods were examined for improving the outcome in these children. METHODS: After remission induction with prednisone, vincristine, daunorubicin, and asparaginase (PVDA) and consolidation chemotherapy with teniposide and cytarabine, patients received weekly continuation chemotherapy with rotating pairs of drugs, comprised of teniposide and cytarabine and vincristine and cyclophosphamide. In addition, they were randomized to receive or not receive repeated reinduction with PVDA. Patients with matched sibling donors were allowed to receive allogeneic bone marrow transplantation (BMT) instead of continued chemotherapy. RESULTS: Of 297 evaluable patients 258 (87%) achieved second complete hematologic remission. However, only 23 of these patients remained continuously free of leukemia > or =7 years after chemotherapy or BMT. Neither PVDA pulses nor BMT appeared to influence outcome at a statistically significant level. CONCLUSIONS: The results of the current study confirm prior reports of the low cure rate of children with ALL who experience hematologic recurrence during initial therapy or shortly after its cessation. New approaches are needed to prevent and retreat hematologic recurrence in pediatric ALL patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Treatment of alpha chain disease. Results of a prospective study in 21 Tunisian patients by the Tunisian-French intestinal Lymphoma Study Group.

Between 1981 and 1985, the authors studied 21 Tunisian patients with alpha chain disease. Twenty of 21 underwent laparotomy. According to Galian et al. six patients were classified Stage A, two Stage B, and 13 Stage C. The therapeutic regimen included the following: (1) Antibiotics: In the case of intestinal bacterial overgrowth (IBO), antibiotics selected by their antibiograms were delivered; in absence of IBO, metronidazole plus ampicillin were first given. The antibiotic treatment was changed in case of therapeutic failure. (2) Chemotherapy: From 1981 to 1983 a cyclophosphamide, Adriamycin (doxorubicin), teniposide (VM-26), prednisone (CHVP) protocol (Adriamycin 35 mg/m2, teniposide 50 mg/m2 day 2, cyclophosphamide 300 mg/m2 days 2 through 4, prednisone 40 mg/m2 days 1 through 10) was used. After 1983 bleomycin 15 mg, Adriamycin 30 mg, vinblastine 10 mg were given on day 15. Serum immunoelectrophoresis and immunohistochemical study of duodenojejunal specimens were made on a 3-month and 6-month basis, respectively. Survival curve analysis was made according to Kaplan and Meier. Results were as follows: (1) Stage A: Six patients were first treated by antibiotics alone; two complete responses (CR) persisting 42 and 55 months later were observed, respectively. The four antibiotic failures were submitted to further chemotherapy with four subsequent failures and two deaths. (2) Stage B-C: Chemotherapy led to nine CR with one precocious relapse, a salvage chemotherapy allowing to one more CR. (3) All stages mixed, percentage of survival reached 90 +/- 12% at 2 years and 67 +/- 25% at 3 years, all patients alive beyond 3.5 years being disease-free.

Actuarial Analysis↗
PubMed1991

New chemotherapies for ovarian cancer. Systemic and intraperitoneal podophyllotoxins.

The epipodophyllotoxin derivatives etoposide and teniposide have been evaluated intermittently for possible use in the treatment of ovarian cancer. Conflicting studies suggest that variables such as dose and prior treatment have a major influence on outcome. Response rates ranged from 0% to 40% in five series with teniposide, and from less than a 10% overall response rate to greater than a 10% complete response rate in nine studies with etoposide. One study documented activity with oral etoposide. However, because all patients had received various prior chemotherapies, firm conclusions regarding the activity of etoposide could not be drawn. These results, and the expectation of synergy with etoposide and cisplatin, led to several studies that combined etoposide with platin compounds by the systemic and intraperitoneal (IP) routes. Various studies have used intravenous drug combinations of these agents in both previously treated and untreated patients. One study, which used carboplatin instead of cisplatin, reported only seven failures among 26 previously untreated patients. Conversely, the prominent toxicities reported by another study were discouraging, and responses did not exceed what might be expected from cisplatin alone. Studies of analogous combinations administered IP are ongoing. A favorable experience, which was initially reported by the University of California (San Diego group), is being confirmed by other investigators. This has prompted the incorporation of etoposide into first-line strategies. The pharmacologic advantage of etoposide by the IP route (related to its high protein binding) may provide appropriate dose intensity against IP disease while sparing systemic toxicities. Finally, systemic dose intensity with autologous bone marrow support indicates some promise for etoposide in combination with high-dose alkylating drugs.

Combined Modality Therapy↗
PubMedDate not supplied

Intensive retreatment of adults and children with acute lymphoblastic leukemia.

Twenty-three patients (16 adults) failing their first or subsequent (n = 8) intensive treatment for de novo acute lymphoblastic leukemia (ALL) and chronic myeloid leukemia lymphoid blast phase (n = 2) were managed with protocol POG 8201, originally introduced in relapsed ALL of childhood. In this programme, a four-drug induction phase is followed by early consolidation with teniposide-cytarabine, intrathecal chemotherapy, continuation weekly chemotherapy alternating teniposide-cytarabine with vincristine-cyclophosphamide, and periodic reinduction courses. Fourteen adults and five children with ALL achieved a complete response (CR) (86 per cent). The highest response rate (100 per cent) was obtained in 12 patients treated at first relapse after an initial CR of greater than 18 months (p = 0.07). Median duration of CR was 8 months in adults and 11 months in children. A longer than previous one CR (inversion) was obtained in four cases. Four ALL patients were successfully transplanted from a matched sibling after 3-11 months from achievement of CR. Median overall survival in adults with ALL was 11 months, significantly longer than for 40 comparable cases treated intensively but without rotational continuation therapy in previous years (p less than 0.001). This regimen is applicable to adults with relapsed ALL, where prolongation of survival may allow time for effective salvage with bone marrow transplantation.

Adolescent↗
PubMed1994

Damage induced in episomal EBV DNA in Raji cells by antitumor drugs as measured by pulsed field gel electrophoresis.

The studies described below were carried out to analyze the damage induced by DNA active drugs to episomal (Epstein-Barr virus, EBV) DNA in the Raji Burkitt's lymphoma cell line. This work: (i) applies pulsed-field gel electrophoresis (PFGE) techniques to quantify DNA damage on a large (approximately 180 kbp), circular target, (ii) investigates the DNA strand-scission behavior of different classes of drugs on the EBV episome, and (iii) compares EBV episomal damage to that generated in genomic DNA in the Raji cell line. Cells were treated with ionizing radiation to induce random strand scission, and the migration of topological forms of EBV was measured using PFGE. DNA damage induced in the episome by DNA active drugs was then assayed. Three drugs, acting by different types of DNA interactive mechanisms, were used: bleomycin, an intercalative DNA strand-scission agent; and amsacrine (mAMSA) and teniposide (VM26), intercalative and nonintercalative topoisomerase II active drugs, respectively. Rad equivalency of damage was determined by comparing the drug-induced change in percentage of Forms I and III to that generated by ionizing radiation. Additionally, single- and double-strand scission induced in genomic (total cellular) DNA by X-rays, bleomycin, amsacrine, and teniposide were assayed by high-sensitivity alkaline and neutral filter elution techniques. We demonstrate that pulsed-field gel electrophoresis is a useful technique for measuring form conversion in large episomal DNA. While all three drugs effect both episomal and genomic DNA strand scission, bleomycin appears to preferentially damage the EBV episome. The topoisomerase II active drugs mAMSA and VM26 show no evidence of episome-directed damage in this system and, in fact, damage genomic DNA at somewhat higher rates.

Amsacrine↗
PubMed1995

An adherent cell model to study different stages of apoptosis.

Apoptosis in the classical thymocyte model occurs very rapidly making it difficult to study the intermediate steps in the process. An alternative adherent cell model is characterized and proposed in this paper. HT29 cells treated with a teniposide were collected at various times for morphological and biochemical assessments. Large DNA breaks (450-500, 350-400, 100-200 kb) were observed in these cells between 6 and 24 h. The larger DNA breaks appeared initially and in progression such that the smaller DNA break of 100-200 kb became apparent by 24 h. These changes in DNA corresponded with an increase in cell diameter and a gradual rounding and detaching of cells from each other but not from the tissue culture plates. The smallest DNA break of 23-50 kb appeared at 48 h and persisted throughout the 96 h of incubation. DNA ladders of 180- to 200-bp oligomers were also observed between 48 and 96 h and these coincided with the presence of small floating cells. Changes in cell adherence after teniposide treatment have permitted the consistent isolation of cells in four distinct morphological and biochemical stages of apoptosis: (1) "preapoptotic," (2) "swelling," (3) "rounding," and (4) "floating." The main advantages of this adherent cell model are: (1) apoptosis occurs very slowly (minimum of 48 h) permitting the observation of progressive changes; (2) cells from four stages of apoptosis can be used to study the sequence of events of other biochemical and genetic factors involved in the process; and (3) extracellular matrix proteins are present in this model so their participation in apoptosis, if any, can be determined.

Adenocarcinoma↗
PubMed1996

Early chemotherapy and concurrent radio-chemotherapy in high grade glioma.

PURPOSE: The poor results from treatment of high grade glioma prompted us to explore new protocols involving concurrent radio-chemotherapy. Our primary objective was to evaluate the feasibility of very early postoperative chemotherapy with BCNU, concurrent radio-chemotherapy with carboplatin and teniposide, and post-radiotherapy BCNU. Our secondary objectives were to evaluate time to progression, and overall survival. PATIENTS AND METHODS: We treated 24 newly diagnosed patients (pts) with BCNU 150 mg/m2 seven days after surgery. Thirty days later, we started radiotherapy, 1.8 to 2 Gy/day for 5 days a week on limited fields up to 60 Gy, and concurrent chemotherapy with carboplatin 250 mg/m2 on days 1, 22, and 43, and teniposide 50 mg/m2 on days 1, 2, 3, 22, 23, 24, 43, 44 and 45. Two cycles of 150 mg/m2 BCNU were then given at 30 and 70 days, respectively, after the end of the radio-chemotherapy course. Therapy was then suspended, but if disease progression was evident, treatment was resumed with drugs that had not been previously employed. Surgical reintervention was not routinely considered. RESULTS: Following radio-chemotherapy treatment in the 24 pts evaluable for response, we observed partial remissions in 8 cases (33%) and stable disease in 12 (50%). Actuarial estimates of progression free survival (PFS) were 33 weeks, with 56 wks for anaplastic astrocytoma and 31 weeks for glioblastoma. Median survival time (MST) of all pts was 58 weeks; 51 weeks for glioblastoma and was not reached for anaplastic astrocytoma. This regimen was feasible. Of 144 planned cycles, 139 were delivered, and among these only in 13 and 9 cycles the doses were reduced by 75 and 50%, respectively. We did not observe any gastrointestinal toxicity. Grade 2 hematological toxicity occurred in 25% of pts. grade 3 in 4% and neurological toxicity in 3% of the pts during BCNU delivery, probably due to a sharp increase in intracranial pressure. CONCLUSION: Early chemotherapy, concurrent chemo-radiotherapy and brief post-radio-therapy chemotherapy are feasible and well tolerated. The objective response and disease stabilization rates appear similar to previous experiences.

Adult↗
PubMed1989

Association of sorcin with drug resistance in L1210 cells.

L1210 sublines independently selected for resistance to teniposide (VM-26), etoposide (VP-16), doxorubicin (DOX), dactinomycin (DACT), or vincristine (VCR) express an anionic, 22-kDa protein that is not observed in extracts of parental L1210 cells. Antibody raised against sorcin, an acidic calcium-binding protein overproduced in many other cells resistant to these agents, cross-reacts with the 22-kDa polypeptide. The levels of the 22-kDa protein (sorcin) increase with the relative levels of drug resistance of the L1210 sublines. The appearance of sorcin in these various sublines further supports the notion that the overproduction of this protein is related to the general phenomenon of multidrug resistance rather than to specific drug resistance and that selection for resistance to teniposide produces L1210 sublines with multidrug resistance.

Animals↗
PubMed1994

Epipodophyllotoxins in the treatment of childhood cancer.

We reported marked biologic activity with the epipodophyllotoxins in phase I/II studies of childhood cancer conducted in the 1970s. We have since extensively used the combination of teniposide and ara-C in the treatment of acute lymphoblastic leukemia (ALL). Initially we treated patients with refractory disease and found that the combination lacked clinical cross-resistance with standard antileukemic drugs. This formed a rationale to move teniposide and/or etoposide to front-line therapy of childhood ALL. The superior results projected for our last trial, an overall cure rate of about 75%, are attributable in part to early use of epipodophyllotoxins. This class of agents is also used extensively in the treatment of newly diagnosed childhood solid tumors, including neuroblastoma, medulloblastoma, rhabdomyosarcoma, and germ-cell tumors. Secondary leukemias following treatment with epipodophyllotoxins have been reported in a small subset of patients. Current data show that the most important risk factor is the schedule of drug delivery, which has led to appropriate protocol modifications.

Antineoplastic Combined Chemotherapy Protocols↗