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S O'Reilly

Publications and source records attributed to S O'Reilly.

At least 55 records · Page 3Linked to original sources
PubMed1998

Clinical Guidelines for Managing Topotecan-Related Hematologic Toxicity.

PURPOSE: Topotecan, a semisynthetic water-soluble camptothecin analog, was recently approved as a second-line treatment for women with ovarian cancer. In clinical trials, hematologic toxicity has been the predominant toxicity associated with its use. The purpose of this article is to provide guidelines on the clinical management of these toxicities. METHODS: The guidelines on the management of hematologic toxicities associated with topotecan therapy for advanced ovarian cancer patients were established through a review and analysis of phase I, II, and III clinical trials. RESULTS: In phase I studies, noncumulative neutropenia was the predominant toxicity associated with topotecan therapy. In subsequently conducted phase II trials, thrombocytopenia related to prior carboplatin and alkylating agent therapies has become a prominent toxicity, and neutropenia has been more severe than anticipated from phase I studies. The risk for both toxicities relates to the extent of prior myelosuppressive chemotherapy and to renal impairment. These toxicities can be managed through the identification of high-risk patients and implementation of appropriate prophylactic measures. Such measures include dose reductions or the use of hematopoietic growth factors. For patients with persistently low blood cell parameters, transfusion therapy remains a viable option. CONCLUSION: Hematologic toxicities associated with topotecan therapy are noncumulative. Consequently, once a dosing regimen is established, toxicity patterns are predictable. Pretreatment assessment of the nature and toxicities of prior therapy and renal function should assist the clinician in preventing complications caused by the myelosuppressive effects of topotecan therapy.

Journal Article↗
PubMed1998

Dose-dependent transformation of cells of human fibroblast cell strain MSU-1.1 by cobalt-60 gamma radiation and characterization of the transformed cells.

Cells from an infinite-life-span near-diploid human fibroblast cell strain, MSU-1.1, were transformed after a single exposure to 60Co gamma radiation. The frequency of transformation as measured by the number of induced foci per 10(6) cells was a linear function of dose. Cells from 13 independent foci from gamma-irradiated cell populations and one from a nonirradiated cell population were isolated, clonally expanded and assayed for characteristics of malignantly transformed cells. Eight of the 13 focus-derived cell strains from the irradiated populations formed tumors in athymic mice with latent periods (time required for the tumors to reach 1 cm in diameter) of 4-27 weeks. Of these 8 cell strains, 3 were fully growth factor-independent, formed large colonies (> 120 microm in diameter) in 0.33% agarose at a high frequency (50%), and produced malignant tumors with a mean latency of 6 weeks or less at all sites injected. Four others formed colonies in agarose at a slightly lower frequency, were only partially growth factor-independent, and produced malignant tumors with a longer mean latency (7-18 weeks). The tumor-derived cell lines from these latter 4 cell strains, when tested for growth in agarose, showed markedly enhanced anchorage independence. The eighth tumorigenic focus-derived cell strain was growth factor-independent but could not produce large colonies in agarose. It produced benign tumors (fibromas) with a mean latency of 27 weeks. All 8 tumorigenic focus-derived cell strains had lost the transactivating function of the TP53 (formerly known as p53) gene. However, loss of TP53 activity was not sufficient to cause tumorigenicity since 3 of the 6 nontumorigenic focus-derived cell strains had also lost all TP53 transactivation function. The other 3, which included a cell strain from the unirradiated control, had wild-type TP53 alleles and did not form tumors. These latter results support the hypothesis that loss of TP53 transactivating function plays a role in focus formation, but does not directly cause tumorigenicity. This is in agreement with studies that demonstrate that the loss of TP53 transactivation facilitates the other changes required for tumorigenicity.

Animals↗
PubMed1997

4-Demethylpenclomedine, an antitumor-active, potentially nonneurotoxic metabolite of penclomedine.

Penclomedine [3,5-dichloro-4,6-dimethoxy-2-(trichloromethyl)pyridine], an antitumor agent, is currently in Phase I clinical trials and is believed to be a prodrug. In these studies, cerebellar effects have been dose limiting. Previous studies identified 4-demethylpenclomedine (4-DM-PEN) as the major plasma metabolite in rodents and humans. 4-DM-PEN was demonstrated to be an antitumor-active metabolite of penclomedine in vivo when evaluated against the penclomedine-sensitive MX-1 human breast tumor xenograft implanted either s.c. or intracerebrally and is believed to be on the metabolic activation pathway of penclomedine. Because earlier studies revealed an absence of neurotoxic cerebellar effects for 4-DM-PEN in contrast to penclomedine in a rat model, this metabolite may be a candidate for an alternative to penclomedine in the clinic for treatment of breast cancer or brain tumors, if the cerebellar effects of penclomedine preclude its further clinical development. Because neither penclomedine nor 4-DM-PEN were very active in vitro, the metabolism of penclomedine was also investigated using rat liver microsomes in an attempt to identify the ultimate active form of the drug. Metabolites and putative metabolites were prepared by chemical synthesis for antitumor evaluation in vitro and in vivo. A reductive metabolite, alpha,alpha-didechloro-PEN, was observed to be much more cytotoxic than penclomedine or 4-DM-PEN in vitro, but evaluation of this and the other metabolites and putative metabolites in vivo against the MX-1 tumor failed to identify any active metabolite among the structures evaluated other than 4-DM-PEN. The limited activity of 4-DM-PEN in vitro indicates that it, like penclomedine, is also a prodrug, demonstrating a need for additional studies on the metabolic activation of penclomedine to identify the ultimate active form of the drug.

Animals↗
PubMed1997

Radiation-induced carcinogenesis: studies using human epithelial cell lines.

It has proved difficult to develop suitable models to study radiation-induced carcinogenesis by using human epithelial cells. However, immortalised human epithelial cell lines have proved useful. Unirradiated cells from the human keratinocyte cell line (HPV-G) and the human embryonic lung cell line (L132) were found to be tumourigenic in T-cell-deficient mice; thus, they are not suitable for transformation studies. Human urothelial cell lines (SV-HUC-1, NT11, BC16) and the human thyroid epithelial cell line (HTori-3) were nontumourigenic. The urothelial cell lines were refractory to radiation-induced carcinogenesis, and only one small tumour was observed in 57 mice that received irradiated cells. Whereas tumours were not produced following irradiation of these urothelial cells, changes in anchorage-independent growth were observed after a single dose of 8 Gy gamma-irradiation but not after 2 or 4 Gy. Irradiation of the human thyroid epithelial cell line (HTori-3) in vitro resulted in tumour formation. Passaging of the cells in vitro before injection did not seem to be critical. Some of the cell lines derived from the primary thyroid tumours exhibited p53 mutations in exons 5, 6, 7, and 8, as detected by single-stranded conformational polymorphism (SSCP) analysis. Thus, the human thyroid epithelial cell line (HTori-3) looks promising as a model for investigating the molecular events in radiation-induced carcinogenesis.

Animals↗
PubMed1997

Experimental chemotherapeutic agents for the treatment of colorectal carcinoma.

Colorectal cancer is the third leading cause of cancer mortality for men and women in the United States. For the past 40 years fluorouracil has been the only agent with significant activity in this disease. More recently, advances in our understanding of the molecular biology of cancer have permitted the development of effective new agents for this disease. This article examines the current and future status of these new agents.

Animals↗
PubMed1997

Advanced diffuse large-cell lymphoma treated with 12-week combination chemotherapy: natural history of relapse after initial complete response and prognostic variables defining outcome after relapse.

PURPOSE: To define both the natural history of and prognostic factors affecting outcome post relapse from a complete response in advanced stage diffuse large-cell lymphoma. PATIENTS AND METHODS: A total of 468 patients aged 17-74 years received the 12-week duration chemotherapy regimens MACOP-B, VACOP-B and ACOP-12 between 1 April 1981 and 31 December 1995 for advanced stage diffuse large, mixed or immunoblastic lymphoma. Of these 402 entered a complete remission, 97 (24%) of whom subsequently relapsed. Initial staging data, follow-up, and relapse information were analyzed to define the natural history of relapse and also subjected to univariate and multivariate correlation with overall (OS) and failure free survival (FFS). RESULTS: Eleven percent of the relapses were low grade. All other relapses were of intermediate grade with 75% occurring within the first two years, the remainder up until the eleventh year. Median and five-year OS from the time of relapse for intermediate grade relapse were 12 months and 20%; for FFS they were eight months and 18% respectively. Adverse independent factors, for both OS and FFS were: less than one year to relapse, decreasing performance status at relapse, and more than three nodal sites at relapse. CONCLUSIONS: Low-grade relapse is not uncommon in patients who initially presented with diffuse large cell lymphoma. As the management of low- and intermediate grade disease is so different biopsy proof of the nature of the relapse is of value. The prognostic factors identified need to be taken into consideration when analyzing results from trials of secondary treatment so as to avoid erroneous conclusions about comparative treatment efficacy.

Adolescent↗
PubMed1997

Central antitussive activity of the NK1 and NK2 tachykinin receptor antagonists, CP-99,994 and SR 48968, in the guinea-pig and cat.

1. The purpose of this study was to investigate the antitussive activity and sites of action of the NK1 and NK2 tachykinin receptor antagonists, CP-99,994, SR 48968, and the racemate of SR 48968, SR 48212A in the cat and guinea-pig. 2. Guinea-pigs were dosed subcutaneously (s.c.) with CP-99,994, SR 48212A or SR 48968 one hour before exposure to aerosols of capsaicin (0.3 mM) to elicit coughing. Coughs were detected with a microphone and counted. 3. Intracerebroventricular (i.c.v.) cannulae were placed in the lateral cerebral ventricles of anaesthetized guinea-pigs. Approximately one week later, the animals were dosed with CP-99,994 or SR 48212A (i.c.v.) and exposed to aerosols of capsaicin (0.3 mM) to elicit coughing. 4. Cough was produced in anaesthetized cats by mechanical stimulation of the intrathoracic trachea and was monitored from electromyograms of respiratory muscle activity. Cannulae were placed for intravenous (i.v.) or, in separate groups of animals, intravertebral arterial (i.a.) administration of CP-99,994, SR 48212A or SR 48968. Dose-response relationships for i.v. and i.a. administration of each drug were generated to determine a ratio of i.v. ED50 to i.a. ED50, known as the effective dose ratio (EDR). The EDR will be 20 or greater for a centrally active drug and less than 20 for a peripherally active drug. 5. In the guinea-pig, CP-99,994 (0.1-30 mg kg-1, s.c.), SR 48212A (1.0-30 mg kg-1, s.c.), and SR 48968 (0.3-3.0 mg kg-1, s.c.) inhibited capsaicin-induced cough in a dose-dependent manner. Capsaicin-induced cough was also inhibited by i.c.v. administration of CP-99,994 (10 and 100 micrograms) or SR 48212A (100 micrograms). 6. In the cat, both CP-99,994 (0.0001-0.3 mg kg-1, i.a., n = 5; 0.003-3.0 mg kg-1, i.v., n = 5) and SR 48212A (0.003-1.0 mg kg-1, i.a., n = 5; 0.01-3.0 mg kg-1, i.v., n = 5) inhibited mechanically induced cough by either the i.v. or i.a. routes in a dose-dependent manner. SR 48968 (0.001-0.3 mg kg-1, i.a., n = 5; 0.03-1.0 mg kg-1, i.v., n = 5) inhibited cough when administered by the i.a. route in a dose-dependent manner, but had no effect by the i.v. route up to a dose of 1.0 mg kg-1. Intravenous antitussive potencies (ED50, 95% confidence interval (CI) of these compounds were: CP-99,994 (0.082 mg kg-1, 95% CI 0.047-0.126), SR 48212A (2.3 mg kg-1, 95% CI 0.5-20), and SR 48968 (> 1.0 mg kg-1, 95% CI not determined). The intra-arterial potencies of these compounds were: CP-99,994 (1.0 microgram kg-1, 95% CI 0.4-1.8), SR 48212A (25 micrograms kg-1, 95% CI 13-52), and SR 48968 (8.0 micrograms kg-1, 95% CI 1-32). The derived EDRs for each compound were: CP-99,994, 82; SR 48212A, 92; and SR 48968, > 125. 7. We concluded that CP-99,994 and SR 48968 inhibit cough in the guinea-pig and cat by a central site of action. In the cat, the antitussive action of these compounds appears to be solely by a central site.

Animals↗
PubMed1997

Muscle weakness in osteoarthritis.

Muscle has an integral role in the structure and function of joints. Evidence for muscle weakness in osteoarthritis of the knee exists and is not fully explained by the effects of aging. Weakness is associated with pain and disability. The temporal relationship requires further study, but preliminary evidence for a causative role is emerging. Muscle weakness can be assessed in various ways. Voluntary measures of strength are affected by degree of effort. In osteoarthritic patients, as in other patient groups, effort may be influenced by pain and psychologic outlook. Techniques to estimate muscle activation are available but have yet to be fully explored in osteoarthritis. Quadriceps exercises increases strength and may have beneficial effects on pain and function. The long-term benefits of exercise for therapy and possible prevention of osteoarthritis are not yet known. This is an exciting area of research, and it is anticipated that more findings will emerge in the near future.

Aging↗
PubMed1997

Phase I trial and pharmacologic trial of sequences of paclitaxel and topotecan in previously treated ovarian epithelial malignancies: a Gynecologic Oncology Group study.

PURPOSE: A phase I and pharmacologic study to evaluate the feasibility of administering paclitaxel (PTX) in combination with topotecan (TPT) without and with granulocyte colony-stimulating factor (G-CSF) in women with recurrent or refractory ovarian cancer. PATIENTS AND METHODS: TPT was administered as a 30-minute infusion daily for 5 days and PTX was given as a 24-hour infusion (PTX-24) either before TPT on day 1 or after TPT on day 5. Each patient received both schedules on an alternating basis every 3 weeks. Sequential dose escalation of TPT or PTX-24 without and with G-CSF resulted in five dosage permutations of TPT/PTX (mg/ m2): 0.75/135 without G-CSF and 0.75/135, 1.25/135, 1.50/135, and 1.25/170 with G-CSF. RESULTS: Twenty-two patients received 109 courses of therapy. Dose-limiting myelosuppression consistently occurred at the first TPT/PTX-24 dose level (0.75/135 mg/m2) in the absence of G-CSF support. Although the addition of G-CSF resulted in reduced rates of complicated neutropenia, the incidences of dose-limiting neutropenia and thrombocytopenia were unacceptably high after the doses of either TPT or PTX-24 were increased. Paired analysis showed similar hematologic toxicities between the two sequences of drug administration. The pharmacologic behavior of both TPT and PTX-24 was not altered by drug sequencing. Major antitumor responses occurred in 40% of patients with measurable and assessable disease, including 45% and 9% of patients with potentially cisplatin-sensitive and -resistant tumors, respectively. CONCLUSION: The recommended doses of TPT on a daily times-five schedule combined with PTX-24 in these patients were 0.75 mg/m2/d and 135 mg/m2, respectively, with G-CSF support. Although this dose of PTX has significant single-agent activity in ovarian cancer, the dose of TPT is much lower than the TPT dose at which single-agent activity has been observed. Due to the inability to administer near relevant single-agent doses of both drugs in combination, as well as the requirement for G-CSF support, further evaluations of this regimen in women with refractory or recurrent ovarian cancer are necessary before it can be recommended for previously treated patients in this setting.

Adult↗
PubMed1997

Phase I and pharmacologic study of penclomedine, a novel alkylating agent, in patients with solid tumors.

PURPOSE: To determine the maximum-tolerated dose (MTD), principal toxicities, and pharmacologic behavior of penclomedine, a novel alkylating agent. PATIENTS AND METHODS: Penclomedine (45 to 550 mg/ m2/d every 3 weeks) was administered as a 1- or 3-hour intravenous (IV) infusion for 5 consecutive days to patients with solid tumors. RESULTS: On a 1-hour dosing schedule, ataxia, vertigo, nystagmus, and a motor aphasia were the principal toxicities of penclomedine. These neurologic effects were dose-related, and evolved from complaints of somnolence and dizziness, to more pronounced signs and symptoms of cerebellar dysfunction. Up to and including doses of 415 mg/m2, these effects were well tolerated and resolved within 2 hours posttreatment. In contrast, both patients treated at the 550-mg/m2 dose level experienced a dose-limiting constellation of perinfusional aphasia and vertigo, with either ataxia of over 2 weeks' duration or recurrent dizziness. Prolongation of the infusion duration to 3 hours at this dose level resulted in less neurotoxicity; however, delayed trilineage hematologic toxicity precluded timely administration on this schedule. A statistically significant relationship was demonstrated between the development of ataxia and maximum plasma concentrations of penclomedine. CONCLUSION: Neurotoxicity was the dose-limiting toxicity (DLT) of penclomedine administered as a 1-hour infusion daily for 5 days every 3 weeks, and the recommended dose for further evaluations was 415 mg/m2. The nature of the principal toxicities and the lack of any detectible antitumor activity indicate that phase II evaluations of penclomedine on this administration schedule should be focused on specific disease settings, such as breast cancer and intracerebral tumors, in which antitumor activity has been demonstrated.

Adult↗
PubMed1996

Phase I and pharmacologic studies of topotecan in patients with impaired hepatic function.

BACKGROUND: Topotecan, a topoisomerase I inhibitor that has demonstrated anticancer activity toward leukemias and solid tumors in clinical trials, is eliminated via hepatic and renal routes. However, dosing guidelines for the administration of topotecan to patients with impaired hepatic function have not yet been established. PURPOSE: We compared the maximum tolerated doses (MTDs), the toxic effects, and the pharmacokinetics and pharmacodynamics of topotecan in patients who had refractory, malignant, solid tumors and who either had or lacked hepatic injury. The potential role of three substrate markers of liver function (indocyanin green [ICG]-- a marker of hepatic blood flow; lorazepam--a substrate marker of hepatic glucuronidation; and antipyrine--a substrate marker for cytochrome P450 activity) in optimizing topotecan doses for patients with liver injury was also evaluated. METHODS: Twenty-one cancer patients, 14 of whom had hepatic injury due to metastatic disease, biliary obstruction, or cirrhosis, were treated with intravenously delivered courses of topotecan consisting of 0.5, 1.0, or 1.5 mg/m2 of drug per day for 5 days. Most patients received more than one course of treatment, with new courses initiated at 3-week intervals. Patient responses (evaluated by tumor measurements) and treatment-induced toxic effects were assessed. Prior to the initiation of topotecan treatment, patients were given intravenous injections of ICG, lorazepam, and antipyrine to determine the plasma pharmacokinetics of these compounds. The pharmacokinetics of topotecan (both the lactone and the carboxylate forms) were determined by analysis of plasma and urine samples collected on the first day of the first course of drug treatment. Scatter plots of area under the plasma concentration versus time curves in relation to percent decreases in either absolute neutrophil count or platelet count were used to explore the pharmacodynamics of topotecan. The Student's t test and the Mann-Whitney U test were used to compare pharmacokinetic parameters between patients with and without abnormal hepatic function. Correlations were assessed using the Spearman's rank correlation coefficient (rs). Reported P values are based on two-tailed tests of significance. RESULTS: Patients with hepatic injury tolerated topotecan doses up to 1.5 mg/m2, i.e., the MTD of this drug established in previous studies. The nature and severity of treatment-induced toxic effects and the pharmacokinetics of topotecan were similar in patients with and without liver injury. No differences were observed in the urinary excretion of topotecan between the two patient groups. Clearances of total topotecan and its lactone species correlated only with clearance of ICG (rs = .64, P = .004; and rs = .68, P = .0017, respectively). The pharmacodynamic effects of topotecan were not altered by liver dysfunction. CONCLUSIONS AND IMPLICATIONS: Cancer patients with hepatic injury can be treated with topotecan at a starting dose of 1.5 mg/m2, given daily for 5 days and administered every 3 weeks. Topotecan dose modifications do not appear to be required for patients with hepatic dysfunction and normal renal function.

Adult↗
PubMed1996

Persistent expression of morphological abnormalities in the distant progeny of irradiated cells.

The phenomenon of delayed heritable lethal damage (often referred to as "lethal mutations") in the progeny of cells which survive irradiation is now well established, but little is known of the mechanism by which this cell death occurs. Current theories suggest a generalised genomic instability affecting all cells which leads to the production of some mutations which are lethal, or alternatively that a lethal mutation gene is activated, mutated or induced by radiation and leads to persistent and random cell death at high levels in the progeny. The aim of this study was to look at the morphology of progeny of irradiated cells at various times after irradiation to establish how widespread morphological abnormalities were in the population and whether there was any evidence that such abnormalities were clonal. Using two different cell lines, the results showed that morphological evidence possibly suggestive of apoptosis occurred in the cultures after all doses of radiation and up to 45 cell doublings after exposure. There was no evidence of a decrease in the numbers of damaged or dead cells in colonies with number of divisions after irradiation, or with decreasing original radiation dose. There was a significant dose-dependent increase in the number of cells with microvilli for both cell lines. The dose-dependency of this effect did not change with number of divisions after irradiation. It is clear that morphological evidence of cellular damage persists for several generations after the initial exposure. The effects are widespread in the cell population, and their constancy over time argues strongly for a general instability and against a clonal mechanism, since clonal descendants should die out and leave undamaged survivors. The lack of evidence for necrosis or senescence together with many morphological changes in the cultures suggestive of apoptosis could indicate an active mechanism of cell death. It is concluded that survivor populations of irradiated cells from two widely different mammalian cell lines demonstrate an altered phenotype including gross morphological changes. These result in a higher probability that cell division will fail to yield two healthy progeny.

Animals↗
PubMed1996

A phase II trial of topotecan in patients with previously untreated pancreatic cancer.

Because currently available chemotherapeutic agents are largely ineffective in the treatment of pancreatic cancer, novel treatments are urgently needed to improve outcomes in this disease. The purpose of this phase II study was to evaluate the anti-tumor activity of topotecan, a hydrophilic camptothecin analog that has demonstrated a wide range of anti-tumor activity in preclinical and phase I studies. Topotecan was administered as a 30 min infusion at a dose of 1.5 mg/m2/day for five consecutive days every 3 weeks, to chemotherapy-naive patients with advanced pancreatic cancer. Neutropenia was the principal toxicity of topotecan on this dosing schedule. No significant anti-tumor responses were observed in 27 patients with measurable disease. The median time to disease progression was 7 weeks and the median survival duration was 17.5 weeks. Thus, topotecan, administered on this schedule, is ineffective for patients with pancreatic carcinoma.

Adult↗
PubMed1996

Phase I and pharmacologic study of topotecan in patients with impaired renal function.

PURPOSE: To determine the toxicities, pharmacokinetics, and recommended doses of the topoisomerase I inhibitor, topotecan, in patients with varying degrees of renal excretory dysfunction. PATIENTS AND METHODS: Fourteen patients with normal renal function [creatinine clearance (CrCl) > or = 60 mL/min] and 28 patients with varying degrees of renal dysfunction were treated with topotecan 0.4 to 2.0 mg/m2/d as a 30-minute infusion for 5 consecutive days every 3 weeks. Plasma and urine samples were obtained to determine the disposition of topotecan. RESULTS: In patients with mild renal dysfunction (CrCl = 40 to 59 mL/min), dose-limiting hematologic toxicity was observed in three of eight patients receiving topotecan 1.0 mg/m2/d and in two of five patients receiving topotecan 1.5 mg/m2/d. In patients with moderate renal dysfunction (CrCl = 20 to 39 mL/min), dose-limiting hematologic toxicity was observed in three of eight patients who received topotecan 0.5 mg/m2/d, and in two of four patients receiving topotecan 1.0 mg/m2/d; these events were more frequently observed in extensively pretreated patients. Pharmacokinetic analyses showed significant correlations between CrCl and the plasma clearance of both total topotecan [Spearman's correlation coefficient (r2) = 0.65, P = .00001] and topotecan lactone (r2 = 0.65, P = .00003). Mean systemic plasma clearance of total topotecan was significantly reduced in patients with mild (P = .04) and moderate (P = .00006) renal dysfunction. There was no evidence of changes in the pharmacodynamic relationship between topotecan exposure (AUC) and myelotoxicity. CONCLUSION: Dose adjustments are required in patients with moderate, but not mild, renal impairment. For patients with moderate renal dysfunction, the recommended starting dose of topotecan is 0.75 mg/m2/d for 5 days every 3 weeks. Moreover, extensively pretreated patients need further dose reductions.

Adult↗