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Biomedical subjects

M Soukop

Publications and source records attributed to M Soukop.

At least 73 records · Page 4Linked to original sources

Flavone acetic acid: a nonlinear pharmacokinetic model.

Flavone acetic acid pharmacokinetics were studied in 31 patients in a phase I clinical trial. The drug was given by i.v. infusions over 1, 1.5, 3, and 6 h at doses ranging from 0.5 to 6.4 g/m2. The pharmacokinetic parameters were determined according to a nonlinear model including Michaelis-Menten-type kinetics. The mean elimination half-life is 4.8 h and the mean volume of distribution of the central compartment, 7.61. Our model predicted a maximal tolerated dose (MTD) of 11.1 g/m2 on the basis of the "therapeutic window" concept, very close to the clinically observed MTD of 10 g/m2. This model is also operational when different protocols of inoculation are considered, such as a divided-dose schedule vs a unique infusion, and indicates that, at the MTD, injections should be made every 72 h to avoid drug accumulation.

Algorithms↗

The pharmacokinetics of high dose cyclophosphamide and high dose etoposide.

We have studied the pharmacokinetics of single agent high dose cyclophosphamide (HDC) (160-240 mg kg-1) given as repeated intravenous (i.v.) infusions to six patients with small cell lung cancer (SCLC), and HDC (180 mg kg-1) combined with etoposide (750-1000 mg m-2) as repeated i.v. infusions to five patients with SCLC and two patients with teratoma. HDC has a similar pharmacokinetic profile to low dose cyclophosphamide, with a half-life of 4.83 +/- 1.3 h. Repeated administration of HDC produced a small but significant shortening of the half life (P = 0.02). The terminal half-life of high dose etoposide was 7.7 +/- 2 h which is similar to our previous results with low dose etoposide (50-300 mg m-2), but the volume of distribution which was 35.5 +/- 11.6 1. was significantly increased (P less than 0.001). Plasma steady state concentrations of 26.2 +/- 11.7 micrograms ml-1 were achieved. The possible mechanism for the alteration of volume of distribution of etoposide will be discussed.

Carcinoma, Small Cell↗

A phase II study of sequential methotrexate and 5-fluorouracil in colorectal carcinoma.

Nineteen patients with locally recurrent or metastatic colorectal carcinomas were treated with 3-weekly cycles of methotrexate (MTX) given as a loading dose of 100 mg m-2 and a subsequent 12 h infusion of 400 mg m-2, followed by 5-fluorouracil (5-FU) 900 mg m-2 as a bolus injection on completion of infusion. No objective responses were seen in 14 evaluable patients. One early death was treatment related, and four patients were withdrawn from the study after a single course as toxicity was considered unacceptable. The results suggest that in this regimen of sequential MTX and 5-FU, any synergism may be restricted to drug toxicity as no therapeutic benefit was evident.

Adult↗

Improving prognosis of Hodgkin's disease in Scotland.

Time trends in mortality from Hodgkin's disease have been studied in Great Britain for the 70-year period, 1911-1980, and incidence in Scotland since 1959. In both Scotland and England and Wales, in each sex, mortality from Hodgkin's disease rose steadily from 1911 until 1970 and thereafter dropped substantially; the greatest fall was apparent in Scottish males. While mortality rates continue to decline in Scotland the incidence has remained fairly constant over the last 25 years suggesting a major change in prognosis for this disease. The introduction of effective chemotherapy and improved techniques of radiotherapy appear to have improved prognosis sufficiently, and to have been made adequately widely available, as to influence overall mortality rates at a national level as well as at the level of the clinical trial. No such improvement in prognosis, however, explains the declines observed in mortality rates among children of each sex in both areas which have taken place since the 1930s. In view of the current knowledge of the aetiology of Hodgkin's disease this fall may have been brought about by changes in socioeconomic factors.

Age Factors↗

A randomized trial of oral nabilone and prochlorperazine compared to intravenous metoclopramide and dexamethasone in the treatment of nausea and vomiting induced by chemotherapy regimens containing cisplatin or cisplatin analogues.

Eighty patients receiving their first course of chemotherapy with regimens containing cisplatin or cisplatin analogues entered this open crossover study comparing nabilone 2 mg and prochlorperazine 5 mg given orally every 12 h for four doses against metoclopramide 2 mg/kg loading dose intravenously (i.v.), then 3 mg/kg as an (i.v.) infusion over 8 h and dexamethasone 20 mg (i.v.) over 3-5 min at the time of chemotherapy. There was complete control of nausea and vomiting in 24 patients (32%) given metoclopramide and dexamethasone compared to 14 patients (19%) given nabilone and prochlorperazine. For the 70 patients who completed the crossover assessment of emesis on a linear analogue scale significantly favoured metoclopramide and dexamethasone (P = 0.02). However, there was no overall patient preference for the metoclopramide and dexamethasone combination (nabilone and prochlorperazine 31 vs. metoclopramide and dexamethasone 26; 13 no preference), because a significant proportion of the patients receiving the cisplatin analogue carboplatin preferred nabilone and prochlorperazine (16 vs. 5; 1 no preference; P = 0.013). For patients receiving cisplatin chemotherapy metoclopramide and dexamethasone remains the antiemetic of choice but for regimens containing carboplatin, nabilone and prochlorperazine is better tolerated and preferred by the patients.

Adolescent↗

A pilot study of carboplatin (JM8, CBDCA) and chlorambucil in combination for advanced ovarian cancer.

Forty-six patients with previously untreated, advanced ovarian cancer received carboplatin (JM8, CBDCA) and chlorambucil (CLB) to assess the efficacy and toxicity of this combination. Carboplatin 300 mg m-2 was given on day 1 with CLB 10 mg daily for 7, 10 or 14 days; 6 treatment courses were given at 4-6 weekly intervals in the absence of disease progression. Tumour response was assessed, where possible, by restaging laparotomy after 6 treatment cycles. Five complete and 16 partial remission were seen in 37 evaluable patients giving an overall response rate of 57%. The median survival of all patients was 15 months. The major toxicity was myelosuppression. Nausea and vomiting were generally minor (WHO, grades I or II) and most courses were given on an outpatient basis. Leucopenia was the major factor causing treatment delays, particularly with the 10 and 14 day CLB regimens. Thrombocytopenia was minimal in the early chemotherapy cycles but the data suggest that cumulative toxicity may occur. This combination may provide a satisfactory degree of efficacy with less toxicity than cisplatin-based regimens.

Adult↗

Pharmacokinetics and anti-emetic efficacy of BRL43694, a new selective 5HT-3 antagonist.

Twenty patients receiving a variety of emetogenic cytotoxics (including cisplatin in 5) were given a single i.v. infusion of 40 micrograms kg-1 of BRL43694 (as the hydrochloride salt) in successive groups of 3-4 patients between 0-6 hours after chemotherapy. Eleven patients were completely protected from vomiting; 9 had mild to moderate nausea and vomiting, but none severe enough to require alternative anti-emetic 'rescue'. In 4 of the patients in whom BRL43694 was delayed until 4-6 h after chemotherapy, vomiting had already begun; in each case immediate termination of vomiting occurred when BRL43694 was infused. No adverse effects attributable to the anti-emetic were observed. Mean pharmacokinetic parameters in 14 patients in whom plasma assay data are available were: Maximum observed concentration = 30.7 ng ml-1; terminal phase half-life = 8.96 h; total body clearance = 0.376 (1 h-1) kg-1; apparent volume of distribution = 2.85 l kg-1. This study shows BRL43694 to be an effective and well tolerated anti-emetic. Further studies aimed at defining an optimal dose and schedule for use against the most emetogenic cytotoxics are in progress.

Adolescent↗

Phase I and pharmacokinetic study of flavone acetic acid.

Flavone acetic acid is the second in a series of compounds based on the flavonoid aglycone ring structure to be clinically evaluated in malignant disease. Preclinical studies have indicated that a minimum plasma level of 150 micrograms/ml is required before therapeutic efficacy (in a wide range of experimental tumors) is seen in mice; both in vitro and in vivo studies also suggest that the duration of drug exposure is crucial in determining activity. Thus a Phase I trial has been performed in a total of 54 patients using 3 schedules, i.e., a 1-, 3-, and 6-h infusion. In each case, treatment was given once weekly for a minimum of 3 weeks. The maximum tolerated doses were 6.4, 6.4, and 10.0 g/m2, respectively. Dose limiting toxicity was denoted by an intense feeling of warmth and flushing with a 1-h infusion, hypotension with a 3-h infusion, and hypotension and diarrhea with a 6-h infusion. No objective responses were seen in this Phase I trial. The recommended doses for Phase II trials of flavone acetic acid in Europe are 4.8 g/m2 over 1 h or 8.6 g/m2 over 6 h. At these doses the peak plasma concentrations obtained are 650 and 388 micrograms/ml, respectively. Total drug exposure (assessed by an area under the curve greater than 100 micrograms/ml) was approximately 50% greater for the 6-h schedule. This Phase I trial indicates that peak plasma concentrations associated with experimental activity are achievable in humans, although optimal drug exposure times have not yet been defined.

Adult↗

Evaluation of the prognostic factors in gastric cancer: the effect of chemotherapy on survival.

This is a retrospective review of 328 consecutive patients with histologically confirmed gastric adenocarcinoma diagnosed in one centre between 1974 and 1984. Of these patients, 128 (39 per cent) had a curative resection, 32 (9.8 per cent) had a palliative resection, 33 (10.0 per cent) had a gastro-enterostomy, 26 (7.9 per cent) had a Celestin tube inserted, 58 (17.7 per cent) had a laparotomy alone, and 51 (15.5 per cent) had no surgical procedure. The 5 year survival was 11 per cent but all long term survivors were patients who had a curative resection. Using multivariate analysis the best predictor of survival after curative resection was the presence or absence of serosal involvement (P = 0.0004). Patients with a long history of presenting symptoms (greater than 6 months) survived longer than those with a short history (P = 0.001). The impact of chemotherapy on the survival of 202 patients with advanced gastric cancer was analysed by multivariate analysis. The median survival of the 50 patients receiving combination chemotherapy was better than that of the 152 who did not (median survivals 160 versus 71 days; P less than 0.001). When deaths occurring within 14 days of diagnosis were excluded, the significance value dropped to P = 0.02. Comparison of the groups treated between 1974 and 1979, when 8 per cent of 92 patients received chemotherapy, with 1980-1984, when 45 per cent of 110 patients received chemotherapy, showed no significant difference in survival.

Adenocarcinoma↗

Failure of conventional chemotherapy in aggressive lymphomas.

Between 1975 and 1982 in 2 centres in Glasgow, 53 previously untreated patients with aggressive non-Hodgkin's lymphomas received chemotherapy consisting of one of the following regimens-CVP, MOPP, CHOP or BACOP. Twenty nine patients (55%) entered complete remission (CR), 20 (38%) had partial remission (PR) and 4 (7%) had progressive disease (PD). Of the 29 patients in CR, 9 have relapsed and died, 5 died of infection, 4 died of non-malignant causes, and 11 (21%) remain alive and disease free. The median survival for the CR group is 40 months. All of the patients in the PR and PD group are dead, median survival 11 months. These chemotherapy regimens will cure only the minority of patients with aggressive lymphomas and the use of more intensive regimens is indicated.

Adult↗

'Apathetic' thyrotoxicosis presenting with hypercalcaemia and spurious normalization of serum thyroid hormone levels.

A patient with thyrotoxicosis presented with weight loss and hypercalcaemia, leading to an erroneous diagnosis of occult malignant disease. Intercurrent illness and drug treatment of hypercalcaemia in this patient caused a depression of circulating thyroid hormone levels, leading to a delay in diagnosis. Radionuclide studies of thyroid function, in contrast, consistently suggested a thyrotoxic state. It is suggested that in this situation, radionuclide studies may give a more accurate assessment of thyroid status than biochemical tests, which may be difficult to interpret in the presence of non-thyroidal illness.

Antithyroid Agents↗

Mitoxantrone versus doxorubicin in combination chemotherapy for advanced carcinoma of the breast.

One hundred fifteen patients with metastatic carcinoma of the breast were treated in a randomized trial of mitoxantrone (Novantrone, Lederle Laboratories, Pearl River, NY) combined with vincristine and prednisolone (VMP) or doxorubicin (Adriamycin, Adria Laboratories, Columbus, OH) combined with vincristine and prednisolone (VAP). In 100 evaluable patients, the objective response rates were 35% for VMP and 61% for VAP, the complete response rates being 6% and 13%, respectively. In responding patients, median time to progression was 6.2 months for VMP and 7.9 months for VAP. The median survival whether measured from primary diagnosis, first metastasis, or from the start of chemotherapy was similar for both regimens. Toxicity, particularly alopecia, was appreciably lower in the VMP treated patients, but subclinical cardiotoxicity was seen within the scheduled dosage for both combinations. We conclude that VAP is clearly more active, but clinically more toxic than VMP. There is no survival advantage conferred by the more toxic combination. Cardiac toxicity is a potential hazard with either drug combination.

Antineoplastic Combined Chemotherapy Protocols↗

Influence of polysorbate 80 (Tween 80) and etoposide (VP-16-213) on the pharmacokinetics and urinary excretion of adriamycin and its metabolites in cancer patients.

Polysorbate 80 (Tween 80) is present in the IV pharmaceutical preparation of VP-16-213 marketed as VePesid (Bristol-Myers) (etoposide 100 mg, benzylalcohol 150 mg, polyethylene glycol 300 3250 mg, citric acid 10 mg, Tween 80 400 mg and absolute alcohol to 5 ml per 100 mg ampule of VP16), to increase its miscibility with blood. We have examined the effects of 400 mg/m2 Tween 80 IV and 100 mg/m2 VP16 on the pharmacokinetics of Adriamycin (ADR, 30 or 40 mg/m2). ADR and metabolite concentrations were measured by HPLC. ADR plasma profiles were best fitted to a bi-exponential decay and a two-compartment open model. Tween 80 did not alter the values of the two ADR half-lives, nor did it affect metabolite kinetics of their urinary excretion. However, in a similar manner and consistently in all patients, both Tween 80 and VP16 increased the volume of distribution of the central compartment for ADR up to 3-fold, decreased the AUC of ADR up to 2-fold and increased its clearance by exactly the same amount. These effects were due to reduced plasma ADR concentrations during the early phase of its kinetics. Urinary excretion of ADR was also increased. In conclusion, VP16 is likely to affect the kinetics of drugs administered with it: early plasma concentrations will fall due to a general physiological effect of Tween 80 on the apparent volume of circulation.

Adult↗

Small cell lung cancer: results of a phase II study of 1,2,4 triglycidylurazol.

Fourteen patients with small cell lung cancer (SCLC) received treatment with 1,2,4 triglycidylurazol (TGU) 600 mg/m2 or 800 mg/m2 as an IV bolus every 4 weeks. Twelve patients had received previous chemotherapy consisting of a five-drug regimen given for the short duration of only 9 weeks. All had measurable disease. Following TGU 11 patients had progressive disease and 3 patients had stable disease. The most frequent toxicity was nausea and vomiting, which occurred in all patients but was generally mild. Myelosuppression was common with a median white blood count nadir of 2.5 X 10(9)/l (range 0.9-7.4 X 10(9)/l) and median platelet count nadir of 76 X 10(9)/l (range 5-173 X 10(9)/l. Alopecia, thrombophlebitis, and hepatic or renal toxicity were not observed. In this study, TGU had no activity in SCLC, and the dose-limiting toxicity was myelosuppression.

Antineoplastic Agents↗

Etoposide: a pharmacokinetic profile including an assessment of bioavailability.

The pharmacokinetics of intravenous etoposide (50-150 mg m-2) have been studied in 17 patients. Bioavailability studies on either the capsule or intravenous (i.v.) formulation were performed in 13 patients, 7 of whom received both oral formulations given in the dose range 50-250 mg m-2. After i.v. administration the mean +/- SD half-lives were t1/2 alpha 0.62 +/- 1.01 h and t1/2 beta 6.04 +/- 2.5 h. The bioavailability of etoposide was extremely variable: for the capsule it was 38 +/- 14% (range 10-55) and for the i.v. formulation it was 53 +/- 25% (range 31-88). The i.v. formulation was not significantly better than the capsule. The results confirm the low and variable bioavailability of oral etoposide.

Administration, Oral↗

TNO-6 has no effect in gastrointestinal cancer: N-acetyl-glucosaminidase shows renal damage.

Twenty-five patients, 16 with gastric cancer and nine with colonic cancer, received TNO-6 30 mg m-2 every four weeks. No objective tumour response was recorded. Nausea and vomiting occurred in 21 patients and was severe in 17. Severe marrow suppression developed in five patients. Renal function was unaffected in all but one patient who developed renal failure, probably as a result of septicaemia. However, the renal tubular enzyme N-acetyl-beta-D-glucosaminidase was measured in six patients and showed a rise in all. In this study TNO-6 had no anti-tumour activity in gastrointestinal malignancy, but produced significant renal tubular damage.

Acetylglucosaminidase↗

A clinical and pharmacokinetic phase I study of 1,2,4-triglycidylurazol (TGU, NSC 332488).

Twenty-six patients with advanced malignancies received TGU given as an intravenous (i.v.) bolus in physiological saline at 3 weekly intervals. The starting dose was 30 mg/m2 with standard graded escalations to 900 mg/m2. Myelosuppression occurred at 800 mg/m2, with a mean nadir of 2.0 +/- 0.8 X 10(9)/l and a mean nadir platelet count of 41 +/- 31 X 10(9)/l. At 800 or 900 mg/m2 nausea and vomiting was WHO grade 0 in 5, grade I in 6, grade II in 11 and grade III in 10 courses of therapy. Alopecia did not occur. TGU was given by i.v. infusion at 800 mg/m2 in 2 patients, both of whom developed severe thrombophlebitis. Five patients given TGU by i.v. bolus developed mild phlebitis. No renal, hepatic or cardiac toxicity was noted. Two patients had partial responses; both had adenocarcinoma of unknown primary origin, one of whom had been resistant to prior therapy with FAM. An HPLC analytical method was developed with a sensitivity of 250 ng/ml. The data from 7 patients studied best fit a one compartment pharmacokinetic model with an exponential decay and a t1/2 of only 2.1 min. In conclusion, the dose limiting toxicity of TGU appears to be myelosuppression and we would recommend a dose of 800 mg/m2 given as an intravenous bolus every 4 weeks for future phase II trials.

Adult↗