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Biomedical subjects

I Hudson

Publications and source records attributed to I Hudson.

At least 19 recordsLinked to original sources
PubMed1999

A comparison of clinical pharmacodynamics of different administration schedules of oral topotecan (Hycamtin)

Prolonged exposure to topotecan in in vitro and in vivo experiments has yielded the highest antitumor efficacy. An oral formulation of topotecan with a bioavailability of 32-44% in humans enables convenient prolonged administration. Pharmacokinetic/pharmacodynamic relationships from four Phase I studies with different schedules of administration of oral topotecan in 99 adult patients with malignant solid tumors refractory to standard forms of chemotherapy were compared. Topotecan was administered as follows: (a) once daily (o.d.) for 5 days every 21 days (29 patients); (b) o.d. for 10 days every 21 days (19 patients); (c) twice daily (b.i.d.) for 10 days every 21 days (20 patients); and (d) b.i.d. for 21 days every 28 days (31 patients). Pharmacokinetic analysis was performed in 55 patients using a validated high-performance liquid chromatographic assay and noncompartmental pharmacokinetic methods. Totals of 109, 48, 64, and 59 courses were given, respectively. Dose-limiting toxicity consisted of granulocytopenia for the o.d. x 5-day dosage, a combination of myelosuppression and diarrhea in both of the 10-day schedules, and only diarrhea in the 21-day schedule. Pharmacokinetics revealed a substantial variation of the area under curve (AUC) of topotecan lactone in all of the dose schedules with a mean intrapatient variation of 25.4 +/- 31.0% (o.d. x 5), 34.5 +/- 25.0% (o.d. x 10), 96.5 +/- 70.1% (b.i.d. x 10), and 59.5 +/- 51.0% (b.i.d. x 21). Significant correlations were observed between myelotoxicity parameters and AUC(t) day 1 and AUC(t) per course of topotecan lactone. In all of the studies, similar sigmoidal relationships could be established between AUC(t) per course and the percentage decrease of WBCs. At maximum-tolerated dose level, no significant difference in AUC(t) per course was found [AUC(t) per course was 107.4 +/- 33.7 ng x h/ml (o.d. x 5), 145.3 +/- 23.8 ng x h/ml (o.d. x 10), 100.0 +/- 41.5 ng x h/ml (b.i.d. x 10), and 164.9 +/- 92.2 ng x h/ml (b.i.d. x 21), respectively.] For oral topotecan, the schedule rather than the AUC(t)-per-course seemed to be related to the type of toxicity. Prolonged oral administration resulted in intestinal side effects as a dose-limiting toxicity, and short-term administration resulted in granulocytopenia. On the basis of this pharmacokinetic study, no schedule preference could be expressed, but based on patient convenience, administration once daily for 5 days could be favored.

Administration, Oral↗
PubMed1998

Five days of oral topotecan (Hycamtin), a phase I and pharmacological study in adult patients with solid tumours.

Topotecan is a specific inhibitor to topoisomerase I. An oral formulation of topotecan is available with a bioavailability of 32-44% in humans. A phase I and pharmacological study of the oral formulation of topotecan administered daily for 5 days every 21 days was performed in adult patients with solid tumours to determine the maximum tolerated dose (MTD). Adult patients with a WHO performance status < or = 2 adequate haematological, hepatic and renal functions, with malignant solid tumours refractory to standard forms were entered into the study. Pharmacokinetics were performed on days 1 and 4 of the first course using a validated high performance liquid chromatographic assay. 29 patients entered the study, all patients were evaluable for toxicity and response. The doses studied in the 29 patients were 1.2, 1.8, 2.3, 2.7 mg/m2/day and a fixed dose of 4 mg/day without surface area adjustment. A total of 109 courses were given. Dose limiting toxicity (DLT) was reached at a dose of 2.7 mg/m2/day and consisted of CTC (NCI-Common Toxicity Criteria) grade IV granulocytopenia. The regimen was well tolerated. Non-haematological toxicities were mild, including fatigue, anorexia, nausea, vomiting and diarrhoea. A significant correlation was observed between the percentage decrease in white blood cells versus the area under the curve (AUC(t)) of topotecan lactone (R = 0.76 P < 0.01) which was modelled by a sigmoidal Emax function. The correlation coefficient between the absolute topotecan dose administered and the AUC(t) was R = 0.52 (P = 0.04). Pharmacokinetics of the fixed dose of 4 mg/day were comparable to the 2.3 mg/m2/day dose. DLT in this phase I study of five daily doses of oral topotecan every 21 days was granulocytopenia. The recommended dose for phase II studies is 2.3 mg/m2/day or alternatively, a fixed dose of 4 mg/day.

Administration, Oral↗
PubMed1998

Continuous infusion of low-dose topotecan: pharmacokinetics and pharmacodynamics during a phase II study in patients with small cell lung cancer.

Preclinical schedule dependency suggests that prolonged maintenance of low plasma levels of topotecan, a specific inhibitor of the nuclear enzyme topoisomerase I, results in optimal antitumor activity. The pharmacokinetics and pharmacodynamics of topotecan, administered as single agent in second-line therapy as a continuous low-dose infusion for 21 days, were evaluated in nine patients with small cell lung cancer (SCLC). Topotecan was administered i.v. as a 21 day continuous infusion every 28 days via an ambulatory pump. Dosages ranged from 0.4 to 0.6 mg/m2/day. Plasma levels of topotecan, the sum of topotecan, and its hydroxy acid congener and the N-desmethyl metabolite were determined at 1, 7, 14 and 21 days during infusion, using a validated high-performance liquid chromatography method with fluorescence detection. Myelosuppression was the most important toxicity. All patients experienced anemia, being severe (grade 3/4) in 55% of all courses. Other adverse effects were relatively mild and reversible, and included nausea, vomiting, diarrhea and fatigue. Three patients achieved a partial response. Mean steady-state concentrations of topotecan (C(ss)) in the first course were 0.46+/-0.17 and 0.47+/-0.19 ng/ml after doses of 0.4 and 0.5 mg/m2/day, respectively. Steady-state levels of the total of topotecan and hydroxy acid (C(ss,tot)) were 1.28+/-0.25 (range 0.93-1.58) and 1.57+/-0.19 (range 1.43-1.70) ng/ml at doses of 0.4 and 0.5 mg/m2/day, respectively. The percentage of the administered topotecan dose excreted in the urine within 24 h was 40+/-14 and 1.2+/-1.0% for total topotecan and N-desmethyltopotecan, respectively. During the second course, C(ss,tot) was significantly higher (p=0.032, paired t-test), which suggests altered topotecan disposition. A sigmoidal relationship was found between C(ss,tot) and the percent decrease in platelets (r=0.76, p=0.018). We conclude that topotecan administered as a 21 day continuous low-dose infusion has activity as single-agent, second-line therapy in patients with SCLC. There was considerable interpatient and intrapatient variability in systemic exposure to topotecan. Differences in organ function might contribute to this variation. Serum aspartate aminotransferase and albumin levels were predictive of topotecan pharmacokinetics.

Adult↗
PubMed1998

Oral topotecan given once or twice daily for ten days: a phase I pharmacology study in adult patients with solid tumors.

Prolonged exposure to topotecan (TPT) in in vitro experiments and in vivo studies in animals yielded the highest antitumor efficacy. An oral bioavailability of TPT of 32-44% enables convenient prolonged administration. Because of unpredictable diarrhea in the third week of the twice daily (b.i.d.) 21-day schedule of p.o. administered TPT and the finding of optimal down-regulation of topoisomerase I level after 10-14 days in mononuclear peripheral blood cells, a shorter period of administration (10 days) was chosen for Phase I and pharmacological studies of oral administration of TPT. Adult patients with malignant solid tumors that were refractory to standard forms of chemotherapy were entered. Two dose schedules were studied: once daily (o.d.) and b.i.d. administration for 10 days every 3 weeks. TPT o.d. for 10 days was studied at dose levels 1.0, 1.4, and 1.6 mg/m2/day, and dose levels were 0.5, 0.6, 0.7, and 0.8 mg/m2 with the 10-day b.i.d. schedule. Pharmacokinetics were performed on days 1 and 8 of the first course using a validated high-performance liquid chromatographic assay and noncompartmental pharmacokinetic methods. Nineteen patients were entered in the 10-day o.d. schedule, with a total of 48 courses given. Dose-limiting toxicity (DLT) was reached at 1.6 mg/m2/day and consisted of common toxicity criteria (CTC) grade IV thrombocytopenia and CTC grade III diarrhea. The maximum tolerated dose was 1.4 mg/m2/day. In the 10-day b.i.d. administration of TPT, a total of 64 courses were studied in 20 patients. DLT was reached at a dose of 0.8 mg/m2 b.i.d. and consisted of CTC grade IV myelosuppression and CTC grade IV diarrhea. The maximum tolerated dose was 0.7 mg/m2 b.i.d. Nonhematological toxicities with both schedules included mild nausea and vomiting, fatigue, and anorexia. Pharmacokinetics revealed a substantial variation of the area under the plasma concentration-time curve of TPT lactone in both schedules. Significant correlations were observed between the myelotoxicity parameters and the area under the plasma concentration-time curve at day 1 of TPT lactone o.d. and b.i.d. The DLT of 10 daily administrations of oral topotecan every 3 weeks consisted of a combination of myelosuppression and diarrhea for both schedules studied. The recommended doses for Phase II studies are 1.4 mg/m2/day for 10 days for the o.d. administration and 0.7 mg/m2 for the b.i.d. schedule.

Administration, Oral↗
PubMed1998

A new surgical timetable.

A consultant timetable which fulfils the requirements of the Calman Report on medical education and the New Deal on junior doctors' hours is presented.

Consultants↗
PubMed1997

Phase I and pharmacologic study of oral topotecan administered twice daily for 21 days to adult patients with solid tumors.

PURPOSE: Topotecan is a specific inhibitor of topoisomerase I. Recently bioavailability of an oral formulation of approximately 30% with limited variability was reported. We conducted a phase I and pharmacokinetic study of the oral formulation of topotecan to characterize the maximum-tolerated dose (MTD), toxicities, pharmacokinetics, and antitumor effects in patients with refractory malignancies. PATIENTS AND METHODS: Patients were treated with oral topotecan given twice daily for 21 days, with cycles repeated every 28 days. In subsequent cohorts, the dose was escalated from 0.15 to 0.6 mg/m2 twice daily. Pharmacokinetics were performed on day 1 and 8 of the first course using a validated high-performance liquid chromatographic assay and noncompartmental pharmacokinetic methods. RESULTS: Thirty-one patients entered the study; one patient was not assessable for toxicity and response as therapy was prematurely interrupted on request of the patient who had not experienced toxicity. Thirty patients received a total of 59 courses. The dose-limiting toxicity (DLT) was reached at a dose of 0.6 mg/m2 twice daily and consisted of diarrhea, which started subacutely at a median onset on day 15 (range, 12 to 20) and resolved after a median of 8 days (range, 7 to 16). Other toxicities were mild, including leukocytopenia, thrombocytopenia, nausea, and vomiting. The MTD was 0.5 mg/m2 twice daily. No responses were observed. Pharmacokinetics showed a substantial variation of the area under the plasma concentration-time curve at time point "t" [AUC(t)] of topotecan and ring-opened product hydroxyacid. A significant correlation was observed between the percentage of decrease in WBC count versus the AUC(t) of topotecan (r = .75), which was modeled by a sigmoidal maximal effect concentration (Emax) function. CONCLUSION: The DLT in this phase I study for chronic oral topotecan for 21 days was diarrhea. The recommended dose for phase II studies is 0.5 mg/m2 twice daily.

Administration, Oral↗
PubMed1997

Topotecan versus paclitaxel for the treatment of recurrent epithelial ovarian cancer.

PURPOSE: Topotecan and paclitaxel were evaluated in a randomized, multicenter study of patients with advanced epithelial ovarian carcinoma who had progressed during or after one platinum-based regimen. PATIENTS AND METHODS: Patients received either topotecan (1.5 mg/m2) as a 30-minute infusion daily for 5 days every 21 days (n = 112) or paclitaxel (175 mg/m2) infused over 3 hours every 21 days (n = 114). Patients had bidimensionally measurable disease and were assessed for efficacy and toxicity. RESULTS: Response rate was 23 of 112 (20.5%) in topotecan-treated patients and 15 of 114 (13.2%) in paclitaxel-treated patients (P = .138). Disease stabilization for at least 8 weeks was noted in 30% of patients with topotecan and 33% of patients with paclitaxel. Median durations of response to topotecan and paclitaxel were 32 and 20 weeks, respectively (P = .222) and median times to progression were 23 and 14 weeks, respectively (P = .002). Median survival was 61 weeks for topotecan and 43 weeks for paclitaxel (P = .515). Response rates for topotecan and paclitaxel were 13.3% versus 6.7% (P = .303) in resistant patients (not responded to prior platinum-based therapy or progressed within 6 months of an initial response) and 28.8% versus 20.0% (P = .213) in sensitive patients (progressed > 6 months after response). Neutropenia was significantly more frequent on the topotecan arm 79% versus paclitaxel arm 23% (P < .01). It was short-lasting and noncumulative in both arms. Nonhematologic toxicities were generally mild (grades 1 to 2) for both agents. CONCLUSION: Topotecan has efficacy at least equivalent to paclitaxel manifested by the higher response rate and significantly longer time to progression.

Adult↗
PubMed1996

Topotecan, an active drug in the second-line treatment of epithelial ovarian cancer: results of a large European phase II study.

PURPOSE: Topotecan is a topoisomerase I inhibitor with preclinical activity against various tumor types. We conducted a large multicenter phase II study with topotecan in ovarian cancer in patients who had failed to respond to one prior cisplatin-based chemotherapeutic regimen. PATIENTS AND METHODS: Topotecan 1.5 mg/m2/d was administered intravenously by 30-minute infusion for 5 days repeated every 3 weeks. As the cisplatin-free interval relates to response in subsequent treatment, patients were stratified in subgroups, ie, cisplatin-refractory, cisplatin-resistant, and cisplatin-sensitive. RESULTS: One-hundred eleven patients entered the study. Nineteen patients were considered to be ineligible; 92 patients were assessable for response. A total of 552 courses were given (median, four per patient; range, one to 17). The major toxicities were leukocytopenia and neutropenia, which were grade 3 to 4 in 54.2% and 69.1% of courses, respectively, but with only 4.3% of these being grade 4 neutropenia plus fever or infectious complications. Prophylactic granulocyte colony-stimulating factor (G-CSF) was given in 20.5% of courses to maintain dose-intensity. Other relatively frequent side effects were alopecia (82%), nausea (36.4%), and vomiting (17.5%). The overall response rate was 16.3%, with one complete response (CR) and 14 partial responses (PRs). In the cisplatin-refractory, cisplatin-resistant, and cisplatin-sensitive strata, the response rates were 5.9%, 17.8%, and 26.7%, respectively. The median duration of time of documented response was 21.7 weeks (range, 4.6 to 41.9). CONCLUSION: Topotecan in a daily-times-five schedule is an effective regimen as second-line treatment in ovarian cancer. Further investigations of topotecan in ovarian cancer, including first-line use and combination with other active agents, are indicated.

Adult↗
PubMed1996

Phase II and pharmacologic study of topotecan administered as a 21-day continuous infusion to patients with colorectal cancer.

PURPOSE: Topotecan is a specific inhibitor of topoisomerase I. Preclinical data have indicated that topoisomerase I inhibitors demonstrate more efficacy and have a greater therapeutic index with prolonged continuous exposure. The feasibility of this concept in humans using a 21-day continuous infusion of topotecan has been reported. We conducted a phase II study of this 21-day continuous topotecan administration schedule in patients with locally advanced, unresectable or metastatic colorectal cancer. PATIENTS AND METHODS: Topotecan, initially applied at a dose of 0.6 mg/m2/d, was administered as a continuous infusion via an ambulatory pump for 21 days repeated every 4 weeks. The starting dose was reduced to 0.5 mg/m2/d, because in five of the first 11 patients, the second course had to be delayed due to prolonged myelosuppression. Forty-two patients entered the study; one patient was ineligible and was excluded from further analyses. RESULTS: The overall response rate was 10%, with one complete and three partial responses. The median response duration was 7 months (range, 4 to 11). With this schedule, the major toxicity was prolonged cumulative myelosuppression, including a marked inhibition of erythropoiesis. A total transfusion of 250 U of erythrocytes was needed to maintain a hemoglobin level greater than 6.0 mmol/L. Other side effects were mild, and included alopecia (47%), periodic nausea (40%)/vomiting (22%), and fatigue (16%). Pharmacokinetic evaluation showed a mean steady-state plasma concentration (Css) of topotecan of 0.62 ng/mL (range, 0.33 to 1.1), with a significant relationship between the Css of topotecan and common cytotoxicity criteria (CTC) grade of leukocytopenia. CONCLUSION: Topotecan administered as a 21-day continuous infusion exerts minor activity as single-agent therapy in patients with metastatic colorectal cancer.

Adult↗
PubMed1995

Topotecan in colorectal cancer: a phase II study of the EORTC early clinical trials group.

PURPOSE: This phase II study with the topoisomerase I inhibitor topotecan was performed to determine its clinical activity and toxicity in patients with metastatic or locally unresectable colorectal cancer. PATIENTS AND METHODS: Topotecan 1.5 mg/m2 was administered intravenously by 30-minute infusion for 5 days. Fifty-nine patients entered the study, 2 were considered ineligible and 57 were evaluable for response and toxicity. RESULTS: Partial response was obtained in 4 of 57 evaluable patients (7%). The median duration of the response was 11 months (range 9.3 to 12.2). This topotecan regimen was very well tolerated. A total of 290 courses were given, with a median of 4 courses per patient (range, 1 to 18). The major toxic effects were leuko- and neutropenia (91%), grade 3-4 in 48% and 79% of courses, respectively, but with only 2 infectious complications. Other side effects were grade 1 alopecia (77%) in 46%, nausea (35%), vomiting (10%), and maculo-papular rash (6%). CONCLUSIONS: Topotecan administered as a daily-times-five regimen has only minor activity as a single-agent therapy in colorectal cancer.

Adult↗
PubMed1994

Posterolateral release for resistant club foot.

We treated 37 infants with 53 idiopathic club feet by posterolateral release alone at a mean age of 2.4 months. They were reviewed after a mean follow-up of 10 years 7 months. Both function and appearance were studied. Seventeen feet had required further surgery, at an average of four years after posterolateral release. In all cases hindfoot equinus had been well corrected; the mean ankle dorsiflexion at review was 15 degrees. Most feet showed subtalar joint movement of between 50% and 75% of normal. Four feet showed poor results: one had a stiff subtalar joint, two feet in one child showed fixed forefoot varus, and one foot had required a Dillwyn-Evans operation at 5.5 years. The overall reoperation rate of 32% at ten years suggests that a radical release operation is not necessary in all patients. Of 59 patients who had only a simple posterolateral release 27 (46%) have satisfactory results.

Child, Preschool↗
PubMed1993

Do diagnosis related groups separate the case-mix of a specialist children's hospital and a paediatric unit in a general hospital?

The ability of diagnosis related groups (DRG) and refinement diagnosis related groups (RDRG) to measure differences in case-mix was investigated using discharge data for patients < 18 years of age from three specialist children's hospitals and four district hospitals. While the three children's hospitals each had a greater percentage of RDRG for more complex patients, only one children's hospital had more complex patients based on DRG and RDRG cost weights and on the percentage of diagnoses per discharge. Cost weights based on USA practices may be inappropriate in Australia, and Australian weights will be necessary for firm conclusions. Refinement diagnosis related groups with appropriate cost weights may be acceptable measures of case-mix in specialist children's hospitals, but they have inherent limitations for paediatric patients in that many complex paediatric patients are ill very seriously with one disorder, whereas complex adult patients usually have secondary diagnoses and secondary procedures. Moreover, no DRG version developed in the US will be suitable for use in Australia unless it takes account of medical costs and transfer practice.

Adolescent↗
PubMed1992

KY nailing of impending and pathological fractures of the proximal femur.

Eight two patients underwent 86 Küntscher Y nailing for impending and pathological fractures of the proximal femur. All but five mobilised post-operatively, thus improving their quality of life. Eighteen patients died in hospital. Prophylactic nailing improved survival. Fifteen out of 86 nailings were followed by complications.

Aged↗
PubMed1992

Charting infant distress: an aid to defining colic.

The value of a 24-hour distress diary, previously validated against a voice-activated audiotape record, was investigated in 30 infants with colic and 30 control infants. The infants with colic had significantly more distress behavior (300.0 minutes vs 102.5 minutes; p < 0.001), although overlap of duration of distress was noted. On the basis of a clinical definition of colic--total distress lasting 180 minutes in a 24-hour period--the diary had a sensitivity of 77% and a specificity of 87%. The sensitivity of the chart was confirmed in a separate study of another 90 infants with colic.

Child Behavior↗
PubMed1992

A review of therapeutic monitoring of chloramphenicol in patients with Haemophilus influenzae meningitis.

Two hundred and seventy-seven serum chloramphenicol concentrations in 90 patients with Haemophilus influenzae type b meningitis were analysed retrospectively. Most patients were given chloramphenicol 25 mg/kg 6 hourly initially. Chloramphenicol concentrations were categorized as pre-dose ('trough') or post-dose ('peak'). Twenty-six per cent of the results were in the potentially toxic range (above 30 mg/L), and 18% were below 10 mg/L. Analysis of 46 pre- and post-dose measurements showed that for the intravenous (i.v.) route of administration, 23% of the pre-dose concentrations were higher than the corresponding post-dose levels and, for the oral route, 42% of the pre-dose levels were higher. Multivariate analysis of covariance demonstrated that chloramphenicol concentrations decreased significantly with increasing number of days of treatment and that the decline was steeper with i.v. administration. The results of this study emphasize the need for therapeutic monitoring of chloramphenicol concentrations, and suggest that chloramphenicol should be given as a loading dose of 40 mg/kg, followed by 25 mg/kg per dose 8 hourly for 3-4 days and then 6 hourly.

Administration, Oral↗