The isolation and identification of cis-diamminedichloroplatinum (ii)-DNA adducts by anion-exchange HPLC and inductively coupled plasma mass-spectrometry

The adducts produced by the reaction of cis-diamminedichloroplatinum(II) with DNA have previously been isolated and characterised. These adducts may be measured at the cellular level by immunochemical detection but the accuracy of this assay is dependent on the number of adducts per nucleotide. We have developed a novel assay for cisplatin-DNA adducts, utilising an established method in which platinated DNA is digested to form a mixture of nucleotides and adducts; these are then separated by anion exchange HPLC. The number of cisplatin-DNA adducts is determined by measurement of the platinum content of the HPLC fractions by inductively coupled plasma mass spectrometry. The assay has been validated by cochromatography of purified drug-DNA adducts whose identity has been confirmed by NMR. We describe an application of the assay, namely the measurement of in vitro removal of cisplatin-DNA adducts from calf thymus DNA by cell free extracts derived from tumour cell lines. Adduct removal is dependent on both the amount of extract protein and the duration of the reaction. Almost 70% of adducts are removed from 5mug of DNA (drug:nucleotide ratio 0.08) by 80mug of extract. Other potential applications of the assay are discussed.

First-into-man phase I and pharmacokinetic study of XR5944.14, a novel agent with a unique mechanism of action

The bis-phenazine XR5944.14 is a novel cytotoxic agent which intercalates into DNA and inhibits transcription. The objectives of this study were to determine the dose-limiting toxicity (DLT), the maximum tolerated dose (MTD) and to describe the pharmacokinetics (PKs) of XR5944.14 when given at doses ranging from 3.6 to 36 mg m⁻² every 3 weeks to patients with advanced tumours. Twenty-seven patients were treated with a total of 77 cycles. Dose-limiting toxicities occurred at doses ⩾24 mg m⁻². Oral mucositis was the most common DLT. Two patients developed acute renal failure possibly related to the study drug. Other less-severe toxicities were diarrhoea, nausea, vomiting and fatigue. Haematological toxicity was mild. One patient showed an objective partial response. Pharmacokinetic analysis was performed during the first cycle of treatment and plasma was assayed for XR5944.14 using a validated liquid chromatography tandem mass spectrometry. The systemic exposure of XR5944.14 increased more than proportionally with increasing dose, with inter-patient variability increasing from dose level 24 mg m⁻² onwards. The lack of correlation between toxicity and PK values makes it difficult to recommend a dose for further study in phase 2 trials. More work is needed to explain the inter- and intra-individual variation in PKs and pharmacodynamics.

Phase I and pharmacokinetic (PK) study of MAG-CPT (PNU 166148): a polymeric derivative of camptothecin (CPT)

Polymeric cytotoxic conjugates are being developed with the aim of preferential delivery of the anticancer agent to tumour. MAG-CPT comprises the topoisomerase I inhibitor camptothecin linked to a water-soluble polymeric backbone methacryloylglycynamide (average molecular weight 18 kDa, 10% CPT by weight). It was administered as a 30-min infusion once every 4 weeks to patients with advanced solid malignancies. The objectives of our study were to determine the maximum tolerated dose, dose-limiting toxicities, and the plasma and urine pharmacokinetics of MAG-CPT, and to document responses to this treatment. The starting dose was 30 mg m(-2) (dose expressed as mg equivalent camptothecin). In total, 23 patients received 47 courses at six dose levels, with a maximum dose of 240 mg m(-2). Dose-limiting toxicities were myelosuppression, neutropaenic sepsis, and diarrhoea. One patient died after cycle 1 MAG-CPT at the maximum dose. The maximum tolerated dose and dose recommended for further clinical study was 200 mg m(-2). The half-lives of both MAG-CPT and released CPT were prolonged (>6 days) and measurable levels of MAG-CPT were retrieved from plasma and urine 4 weeks after treatment. However, subsequent pharmacodynamic studies of this agent have led to its withdrawal from clinical development.

Phase I dose-escalation and pharmacokinetic study of a novel folate analogue AG2034

The novel folate analogue AG2034, which was designed as an inhibitor of GARFT (glycinamide ribonucleotide formyltransferase), was evaluated in this phase I study under the auspices of The Cancer Research Campaign, UK. AG2034 blocks de novo purine synthesis through inhibition of GARFT. A total of 28 patients with histologically proven intractable cancers were enrolled. AG2034 was administered as a short intravenous infusion once every 3 weeks. 8 dose levels ranging from 1-11 mg/m(2)were evaluated with patients receiving up to 6 cycles. Dose-limiting toxicities in the form of mucositis, diarrhoea and vomiting were observed at doses of 6 mg/m(2)and above. Significant levels of thrombocytopenia, neutropenia and anaemia were also recorded. Other sporadic toxicities included fatigue and myalgia. The MTD with this schedule of AG2034 was 5 mg/m(2). Most side effects occurred more frequently with cumulative dosing. In keeping with this, pharmacokinetic analysis revealed evidence of drug accumulation. The AG2034 AUC(0-24)increased by a median of 184% (range 20-389%) from cycle 1 to 3 in all 10 patients examined. No objective antitumour responses were observed in the study.

Pharmacokinetic and pharmacodynamic evaluation of the glycinamide ribonucleotide formyltransferase inhibitor AG2034

Glycinamide ribonucleotide formyltransferase (GARFT) is a component of the de novo purine synthesis pathway. AG2034 is a specific inhibitor of GARFT that was designed based on the GARFT crystal structure. In conjunction with Phase I studies at four clinical centers in the United States and United Kingdom, AG2034 pharmacology was evaluated in 54 patients receiving 1-11 mg/m2 AG2034 as a 2-5 min injection. Blood samples were obtained just prior to and 5, 15, 30, and 45 min, and 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72, and 96 h after bolus injection during course 1. Limited sampling was also performed on course 3. Plasma AG2034 was measured using a sensitive and reproducible ELISA assay. AG2034 demonstrated a trimodal elimination pattern over 24 h, with median half-life (t(1/2))alpha = 8.7 min, t(1/2)beta = 72.6 min, and t(1/2)gamma = 364.2 min. AG2034 systemic clearance ranged from 9.4-144.5 ml/min/m2, and volume of distribution was 1.2-7.6 liters/m2. Course 1 AG2034 area under the concentration versus time curve (AUC) had a linear relationship with dose (r(s) = 0.86). Accumulation of AG2034 was evident, because course 3 AUC was higher than course 1 in 23 of 23 evaluable patients, but was not associated with an increase in erythrocyte AG2034. AG2034 systemic exposure had an impact on toxicity, because course 1 and course 3 AG2034 AUCs were significantly higher for patients with grade III/IV toxicity than patients with less than grade II toxicity (P < 0.001 and P = 0.001 for course 1 and course 3, respectively). This study demonstrates rapid systemic clearance of AG2034 and suggests pharmacokinetic approaches that may minimize patient toxicity and aid the development of this interesting class of anticancer agents.

A pilot study of continuous infusional 5-fluorouracil, doxorubicin and cyclophosphamide in breast cancer

The purpose of this study was to evaluate the toxicity and activity of continuous infusional 5-fluorouracil (5-FU) given at three dose levels in combination with cyclophosphamide and doxorubicin (FAC) in women with breast cancer. Thirty-nine patients with either primary tumours >3 cm prior to surgery (n = 24) or metastatic disease (n = 15) received cyclophosphamide 600 mg/m2 and doxorubicin 50 mg/m2 as an intravenous bolus every 3 weeks for six courses. Continuous infusional 5-FU was delivered via a central venous line for a maximum of 18 weeks at dose levels of 100 mg/m2 per day (n = 6), 150 mg/m2 per day (n = 3) and 200 mg/m2 per day (n = 30). At the 200 mg/m2 per day dose level, 36% of patients required dose delays and 23% dose reductions; there was one death due to neutropenic sepsis. Hickman line complications occurred at all dose levels, particularly thrombosis (18%) and infection (33%). The response rate was 62% (95% confidence interval (CI) 32-84) for metastatic disease, including five complete responses (CRs). The response rate for primary tumours prior to surgery was 81% (95% CI 57-95) including six clinical CRs. Infusional FAC is an active regimen and has an acceptable toxicity profile. It does not, however, appear to offer any significant advantage over other chemotherapy regimens. This study does not support the further evaluation of infusional 5-FU at these doses in combination with doxorubicin and cyclophosphamide.

A Phase I study of capecitabine in combination with oral leucovorin in patients with intractable solid tumors

Capecitabine (Xeloda) is a novel rationally designed fluoropyrimidine carbamate. It passes through the intestinal mucosal membrane intact and is subsequently activated by a cascade of three enzymes resulting in preferential release of 5-fluorouracil (5-FU) at the tumor site. Preclinical studies indicated an enhancement of the therapeutic index when capecitabine was combined with leucovorin. This Phase I trial was designed to determine the safety profile, maximal tolerated dose, and pharmacokinetic profile of the combination of capecitabine plus a fixed dose of p.o. leucovorin (60 mg/day) during administration to patients with refractory advanced cancers. The intention was to administer both drugs continuously, but the starting dose of capecitabine was also the maximum tolerated dose (1004 mg/m2/day) in six patients treated with this regimen. A cycle of treatment was then redefined as leucovorin and capecitabine given p.o., twice daily for 2 consecutive weeks followed by a 1-week rest period. Capecitabine doses from 1004 mg/m2/day to 2510 mg/m2/day were evaluated with the intermittent schedule over approximately 80 courses in an additional 25 patients. The dose-limiting toxicities that defined the maximum tolerated dose at 2000 mg/m2/day were diarrhea, nausea, vomiting, and palmar plantar erythrodysesthesia. The recommended Phase II dose using this schedule was 1650 mg/m2/day of capecitabine plus leucovorin 60 mg/day. Plasma concentrations of capecitabine, intermediate metabolites, and 5-FU were measured in 26 patients on days 1 and 14 of therapy. The pharmacokinetics of capecitabine were characterized by rapid GI absorption, with Cmax at 1 h, followed by conversion to active drug. The coadministration of leucovorin had no effect on the pharmacokinetics of capecitabine. Two patients with colorectal cancer, both previously treated with 5-FU, had partial responses. Phase II studies have confirmed the promising antitumor activity of this drug, and capecitabine is currently in Phase III evaluation.

Angiosarcoma of the penis

Sarcoma of the penis is rare. We report an angiosarcoma that was essentially an incidental finding, despite the presence of metastatic lesions, in a 46-year-old man who presented with hematemesis and melena. The diagnosis of the primary lesion was confirmed by histology, and the presence of secondary lesions by fine needle aspiration cytology. The patient was given one dose of chemotherapy, but died of a myocardial infarction before being able to receive further treatment. The literature pertaining to this very unusual lesion is discussed.

Cystosarcoma phylloides: heterogeneity in a rare tumour type

Mammary cystosarcoma phylloides is a rare tumour, and clear guidelines for its clinical management are lacking. We present three cases from the Western Infirmary which illustrate the range of behaviour that these tumours can manifest, and discuss some of the clinical problems that they present.

Successful thrombolysis of SVC thrombosis associated with Hickman lines and continuous infusion chemotherapy

In a pilot study of continuous infusion 5-fluorouracil and intermittent bolus doxorubicin and cyclophosphamide in women with breast cancer, four of 24 patients developed symptomatic superior vena cava or innominate vein thrombosis associated with the Hickman line, despite prophylactic treatment with very low dose warfarin (1-3 mg/day). In all four patients, local thrombolysis with streptokinase was successful and chemotherapy was continued through the Hickman line under anticoagulant cover, maintaining an international normalized ratio of 2.0-3.0. No patient developed recurrent thrombosis. Prophylactic anticoagulation should be considered in patients receiving continuous infusion chemotherapy through Hickman lines, as they are at risk of proximal vein thrombosis. A randomized study is needed to address the question of the optimum anticoagulant regimen to prevent such thromboses.

Phase I study of accelerated FEC with granulocyte colony-stimulating factor (Lenograstim) support

With the aim of increasing the dose intensity of chemotherapy in breast cancer, 14 patients with stage II-IV breast cancer were treated with FEC chemotherapy at 2 week intervals together with granulocyte colony-stimulating factor (G-CSF) 5 micrograms kg-1 s.c. on days 2-14. Five of six patients completed six courses of 5-fluorouracil 600 mg m-2, epirubicin 60 mg m-2 and cylcophosphamide 600 mg m-2 within 11 weeks. Eight patients were treated with 5-fluorouracil 700 mg m-2, epirubicin 70 mg m-2 and cyclophosphamide 700 mg m-2 and four had dose-limiting toxicity with sepsis, thrombocytopenia or mucositis. All patients who received G-CSF had satisfactory neutrophil counts by day 15 of each course. Cumulative anaemia and thrombocytopenia were observed, but treatment at the first dose was tolerable. Seven of eight patients with measurable disease had partial responses. This regimen permits a 50% increase in dose intensity compared with conventional treatment at 3 week intervals and warrants further evaluation.

Phase I clinical and pharmacokinetic study of 3'-deamino-3'-(2-methoxy-4-morpholinyl)doxorubicin (FCE 23762)

Methoxymorpholinyldoxorubicin (FCE 23762) is a novel, highly lipophilic doxorubicin analogue. It possesses potent in vitro and in vivo antitumor activity including efficacy in multidrug-resistant tumor cell lines. It is also metabolically activated in vivo resulting in an 80-fold increase in potency over the parent drug. In this phase I study the drug was administered by i.v. bolus injection at 3-week intervals. Fifty-three patients with refractory solid tumors were treated; 133 courses of FCE 23762 were administered at doses ranging from 30 to 2250 micrograms/m2. The dose limiting toxicity was reversible myelo-suppression (granulocytopenia and thrombocytopenia), demonstrating a delayed nadir and recovery in comparison to doxorubicin. Other toxicities included transient elevation of hepatic transaminases, delayed and prolonged nausea and vomiting, mucositis, anorexia, fatigue, and diarrhea. Heavily pretreated patients demonstrated more myelosuppression than previously untreated patients at 1250 micrograms/m2. No cardiotoxicity was observed. Four objective tumor responses were seen: one complete response in a patient with pelvic recurrence of cervical cancer; one partial response in a patient with cutaneous and lymph gland metastases from head and neck cancer; and two minor responses in patients with liver metastases from colorectal cancer. Plasma concentrations of FCE 23762 and its 13-dihydro metabolite, FCE 26176, were measured in 20 patients at doses > or = 675 micrograms/m2, using HPLC with fluorescence detection. The area under the plasma concentration-time curve ranged from 30 to 80 ng/h/ml; plasma data suggested linear kinetics in the range of tested doses (although there was considerable interpatient variability). The maximum tolerated dose defined in this study using this schedule is 1500 micrograms/m2. A safe phase II dose for previously untreated patients using this schedule is 1250 micrograms/m2; however, this may actually be below the optimal dose for this patient population.

Epirubicin chemotherapy and advanced breast cancer after adjuvant CMF chemotherapy

There have been conflicting reports on the effect of prior adjuvant chemotherapy on the response of advanced breast cancer to primary chemotherapy. We report a retrospective review of the outcome of chemotherapy with epirubicin 100 mg/m2 for advanced breast cancer in 39 patients who had previously received adjuvant cyclophosphamide, methotrexate and 5-fluorouracil (CMF). The response rate (complete responses plus partial responses) was 38.5%, with a median duration of response of 33 weeks. There was no significant difference in the response rate or duration of survival when these patients were compared with matched controls who had not received adjuvant chemotherapy. However, the limitations of this study were such that an adverse effect of adjuvant CMF on the response to epirubicin cannot be excluded.

Quinidine as a resistance modulator of epirubicin in advanced breast cancer: mature results of a placebo-controlled randomized trial

PURPOSE

To evaluate the effect of quinidine, a putative modulator of P-glycoprotein-mediated drug resistance, on the response rate and toxicity profile of epirubicin in patients with advanced breast cancer.

PATIENTS AND METHODS

Between 1989 and 1992, 223 eligible patients were randomized in double-blind fashion to receive epirubicin 100 mg/m2 by intravenous (i.v.) bolus and prednisolone 25 mg orally twice daily, along with either placebo or quinidine (250 mg) capsules, taken for 4 days before and 2 days after chemotherapy. Treatment was continued for a maximum of eight courses.

RESULTS

Ten eligible patients did not complete the first cycle of treatment. Of the remaining patients, 106 in the placebo arm received 619 courses of treatment, and 107 in the quinidine arm received 612 courses. The median cumulative dose of epirubicin in both arms was 600 mg/m2. The median quinidine level (measured before epirubicin administration in 288 courses) was 5.5 mumol/L; at this concentration, the drug partially reverses anthracycline resistance in multidrug-resistant (MDR) breast carcinoma cells in vitro. There were no statistically significant differences in hematologic or gastrointestinal toxicity between the two arms. The response rate in the placebo arm was 44% (6% complete remission [CR], 38% partial remission [PR]), and in the quinidine arm was 43% (4% CR, 39% PR). Surviving patients have been monitored for a median time of 74 weeks, and there is no significant difference in the overall or progression-free survival between the two arms. The median survival times were 59 weeks for placebo and 47 weeks for quinidine patients. The estimated relative death rate (quinidine/placebo) was 1.2 (P = .247; 95% confidence interval [CI], 0.88 to 1.63).

CONCLUSION

Quinidine at this dose does not significantly alter the toxicity profile, response rate, or survival after epirubicin chemotherapy in patients with advanced breast cancer. This may be due to ineffective modulation of P-glycoprotein by quinidine or the lack of expression of mdr-1 in a sufficient proportion of cells in these tumors, or alternative mechanisms underlying resistance to epirubicin.

The treatment of stage I carcinoma of the cervix in the west of Scotland 1980-1987

OBJECTIVE

To examine the results of different treatments for Stage IA and IB carcinoma of the cervix in patients treated in the West of Scotland between 1980 and 1987.

DESIGN

A retrospective review of case records.

SETTING

The Beatson Oncology Centre, Western Infirmary and Belvidere Hospital, Glasgow, and the departments of gynaecology of hospitals in the west of Scotland.

SUBJECTS

One hundred and five patients with Stage IA and 420 patients with Stage IB carcinoma of the cervix.

RESULTS

A variety of treatments were used for women with Stage IA disease, with an overall actuarial five year survival of 100%. The overall actuarial five year survival for women with Stage IB disease was 79.5%. Patients with Stage IB disease treated by radical hysterectomy (n = 123) or radical radiotherapy (n = 229) had similar five year survival rates (86.3% and 79.5%, respectively), whereas patients treated initially by nonradical surgery (n = 68) had a significantly worse five year survival (68.1%; P = 0.008).

CONCLUSIONS

These results emphasize the need for adequate and appropriate surgery and the centralisation of treatment for early cervical cancer.

Cisplatin-DNA damage recognition proteins in human tumour extracts

Enhanced repair of DNA adducts may be a cause of cis-diamminedichloroplatinum(II) resistance in solid malignancies. Binding of specific damage recognition proteins to the sites of DNA damage may be involved in the initial steps of DNA repair, or alternatively may block access of repair proteins to damaged DNA. Proteins which bind specifically to CDDP-modified DNA were identified in cell extracts from human ovarian carcinoma cell lines by two assays, the gel mobility shift assay and the southwestern blot. In the first assay, proteins complexed with CDDP-modified oligonucleotide and produced two retarded bands, B1 and B2. The B2 complex was partially purified from an ovarian cell extract by anion exchange FPLC, and was shown to bind to DNA damaged by CDDP but not by transDDP or UV irradiation. Using the southwestern blot, proteins of 97, 48, and 25 kD were identified; each of these bound to CDDP-modified but not undamaged oligonucleotide. The partially purified B2 protein fraction contained both the 97 and the 25 kD damage recognition proteins. A human ovarian carcinoma cell line selected in vitro for CDDP-resistance (OV1P/DDP), which is 5-fold more resistant to CDDP than the parental line (OV1P), showed an increase in binding of the 97 and 48 kD damage recognition proteins compared with the parental line. Twelve ovarian cell lines differed by up to 3-fold in their expression of these proteins, but there was no correlation between the amount of damage recognition protein in a cell extract and the cellular sensitivity to CDDP. Damage recognition proteins were also demonstrated in extracts prepared from biopsies of human ovarian, cervical, and testicular malignancies, but there was no apparent difference in the binding activity in extracts from tumours of different CDDP-sensitivity. The functional role of these damage recognition proteins remains to be established.

Phase I and pharmacokinetic study of taxotere (RP 56976) administered as a 24-hour infusion

N-Debenzoyl-N-tert-butoxycarbonyl-10-deacytyl taxol (Taxotere, RP 56976) is a semisynthetic analogue of taxol, prepared from a noncytotoxic precursor extracted from the needles of the European yew tree (Taxus baccata L.). It has a broad spectrum of antitumor activity against a variety of transplantable tumors in mice. In vitro cytotoxicity assays suggest that it is 2-5-fold more potent than taxol. In this phase I study Taxotere was administered by 24 h i.v. infusion at 3-week intervals. Thirty patients with solid tumors refractory to conventional therapy were treated; 70 courses of Taxotere were administered at doses ranging from 10 to 90 mg/m2. Grade 4 neutropenia and grade 3 mucositis were dose limiting but reversible at 90 mg/m2. The pattern and grade of toxicity at this dose were similar in 3 heavily pretreated patients compared with 7 patients who had received a maximum of one previous chemotherapy regimen. Alopecia occurred at 55 mg/m2 and above. Other mild toxicities included phlebitis, diarrhea, emesis, and sensory peripheral neuropathy, but these were neither dose-limiting nor clearly dose-related. One patient treated at 70 mg/m2 had an anaphylactoid reaction following the second dose of Taxotere. No cardiovascular toxicity was observed. No partial or complete responses were documented. Plasma concentrations of Taxotere were determined by high-performance liquid chromatography, and end-of-fusion levels at the maximum tolerated dose exceeded drug concentrations which are cytotoxic in vitro. The maximum tolerated dose for Taxotere administered as a 24-h infusion is 90 mg/m2.

Phase I and pharmacokinetic study of rhizoxin

Rhizoxin is a tubulin-binding cytotoxic compound, isolated from the fungus Rhizopus chinensis, with significant antineoplastic activity in several murine and human tumor models. In this Phase I study, the drug was administered by i.v. bolus injection at 3-wk intervals. Twenty-four patients with refractory solid tumors were treated; 60 courses of rhizoxin were given, at doses ranging from 0.8 to 2.6 mg/m2. Grade 3 mucositis, Grade 4 leukopenia, and Grade 3 diarrhea were dose limiting but reversible at 2.6 mg/m2, the maximum tolerated dose for both previously untreated and heavily pretreated patients. Alopecia and moderate discomfort at the injection site occurred at all doses. Other sequelae, including peripheral neuropathy, phlebitis, and nausea and vomiting, were sporadic and mild. Two heavily pretreated patients with recurrent breast cancer had minor responses to rhizoxin, one at 1.6 mg/m2 and the other at 2.6 mg/m2. Plasma concentrations of rhizoxin were measured by high-performance liquid chromatography. The drug was not detectable (less than 5 ng/ml) at doses of 0.8 mg/m2 and 1.6 mg/m2 and was not measurable 10 min after injection at 2.0 mg/m2. At 2.6 mg/m2, there was considerable intersubject variation in the plasma concentration-time profiles; the area under the curve ranged from 0.29 to 0.96 microgram/ml.min. Rhizoxin has shown some clinical activity in this Phase I study, and a dose of 2.0 mg/m2 is recommended for Phase II studies using this schedule.

Preclinical and phase I studies with rhizoxin to apply a pharmacokinetically guided dose-escalation scheme

BACKGROUND

Rhizoxin is a new macrocyclic lactone isolated from the fungus Rhizopus chinensis which displays broad-spectrum antitumor activity against murine and human tumor xenografts and has activity against a number of vincristine-resistant tumors in vitro and in vivo.

PURPOSE

This study describes the preclinical and clinical pharmacology of rhizoxin to apply a pharmacokinetically guided dose-escalation (PGDE) strategy during the phase I trial.

METHODS

Rhizoxin was administered by a single intravenous bolus injection to female BALB/c mice over the dose range 7.5-18 mg/m2 from which we derived the dose that was lethal to 10% and 50% of the mice (i.e., LD10 and LD50, respectively). The LD10 was 11.7 +/- 0.7 mg/m2 (mean +/- SD), and the LD50 was 14.7 +/- 0.6 mg/m2. Pharmacokinetic studies were integrated with the toxicity study in female BALB/c mice at one-tenth the LD10, one-half the LD10, and the LD10 (i.e., 1.2, 6, and 12 mg/m2, respectively). From these data, a target area under the plasma drug concentration versus time curve (AUC) (i.e., 40% of the LD10 AUC) was calculated for clinical studies. Phase I studies were initiated at 0.8 mg/m2 (one-tenth the equivalent LD10 in male CD1 mice), with the intent of escalating the dose by an extended factor-of-two method until the target AUC and/or maximum tolerated dose (MTD) was reached.

RESULTS

The major drug toxic effects in mice were body weight loss, sluggishness, ataxia, transient changes in hematological parameters, and hematuria. Diarrhea was universal at doses greater than 9 mg/m2, and hind limb paralysis was observed in one of 10 mice, but only at supralethal doses (18 mg/m2). Rhizoxin pharmacokinetics were best described by a two-compartment open model (half-life [t 1/2] alpha = 4.4 minutes +/- 0.9 minute [mean +/- SD], and t 1/2 beta = 84 minutes +/- 20 minutes at 12 mg/m2) and found to be nonlinear with respect to dose. At doses of 1.2, 6, and 12 mg/m2, the respective AUC values were 1.3, 22.4, and 70.6 microM x minute. From these data, a target AUC value of 28 microM x minute (40% of the LD10 AUC) was derived. Rhizoxin was not detectable in patient plasma (less than 5 ng/mL at 0.8 and 1.6 mg/m2), and doses had to be escalated by conventional methods. Myelosuppression was dose limiting in patients: Seven of eight treated at 2.6 mg/m2 experienced World Health Organization grade 3-4 neutropenia, and five of eight developed mucositis. The AUC values at the human MTD (2.6 mg/m2) were in the range of 0.41-1.01 microM x minute, considerably lower than the target AUC of 28 microM x minute.

CONCLUSION AND IMPLICATIONS

Although PGDE schemes have been successfully employed for other antitumor agents, this methodology could not be applied during the phase I trial of rhizoxin. PGDE studies in the future may incorporate comparative murine versus human metabolism studies in vitro with phenotyped liver microsomes. It may also be useful to assess the comparative myelotoxicity of a new drug by performing in vitro cytotoxicity studies on mouse and human bone marrow stem cells.

Phase I and pharmacokinetic study of D-verapamil and doxorubicin

The calcium antagonist verapamil (a mixture of D- and L-racemers) is a potent modulator of the multi-drug resistance phenotype in vitro at a concentration of 6 microM. Clinical studies have shown dose-limiting toxicity of hypotension and heart block when plasma levels approach the concentrations active in vitro. Previous data indicate that the D-isomer is less cardioactive than the L-isomer but they appear to be equipotent in reversing drug resistance in vitro. In an attempt to increase plasma verapamil concentrations, we have treated ten patients (total of 27 courses) with oral D-verapamil (DVPM), 150-300 mg 6 h, and doxorubicin i.v. 70 mg m2 q 3 weeks. Hypotension (supine systolic BP less than 100 mmHg or a fall in systolic BP of greater than 30 mmHg) occurred in 5/6 patients at 1200 mg day DVPM, in 1/5 at 800 mg day, and in 1/5 at 600 mg day. PQ prolongation (greater than 0.23 s) was demonstrated in 2/5 patients at 800 mg day DVPM. Plasma levels of DVPM and its active metabolite norverapamil were measured and, combining these, levels of 3-4 microM were achieved at 1200 mg day DVPM; however this dose is likely to lead to unacceptable toxicity in the outpatient setting. Using an oral outpatient schedule of administration, an appropriate dose of DVPM is 800 mg day. This provides a combined plasma level (for VPM and DVPM) of 2-3 microM. If DVPM is to prove useful as a resistance modulator, it may require to be administered intravenously with careful inpatient monitoring and support.

The role of palliative radiotherapy in malignant mesothelioma

Chest pain is often a major problem in patients with malignant pleural mesothelioma but there are few data regarding the usefulness of radiotherapy (RT) in its palliation. Following a recent retrospective report which suggested that wide-field RT frequently affords pain relief in this disease, we prospectively assessed the effect of hemithorax irradiation on pain control. Twenty-two patients with chest pain due to mesothelioma received 30 Gy in 10 daily fractions to the involved hemithorax. The patients' symptoms were assessed before RT, 1 month after RT, and then 2 monthly. Symptoms were graded by the clinician and the patient, and analgesic requirements were noted at each assessment. Performance status and respiratory status were recorded by WHO and MRC criteria respectively. Nineteen assessable patients have been followed for at least 3 months after RT. The treatment was well tolerated, with nausea and vomiting in only 1 patient. Pain control improved in 13/19 patients at 1 month, but 9/12 patients had worsening chest pain at 3 months, and at 5 months pain control had deteriorated in 6/7 patients. Although partial regression of chest wall masses was seen in 5/9 patients, RT did not appear to delay the progression of respiratory symptoms or radiological changes. The median duration of survival after RT was 4 months. Radiotherapy can relieve pain due to malignant pleural mesothelioma but its effect at this dose is short-lived.

Long-term sequelae of treatment for testicular germ cell tumours

Seventy-four patients previously treated in our department for germ cell tumour of the testis underwent a series of tests to determine the frequency of long-term therapeutic complications. All had received cisplatin-based chemotherapy as part of their treatment. There was a significant deterioration in renal function throughout the group. Eighteen (24%) had supine blood pressure greater than systolic 140 mmHg or diastolic 90 mmHg after treatment but hypertension did not correlate with renal impairment. Raynaud's phenomenon was common after chemotherapy (26/74) as was persistent sensory neuropathy (23/74). Although 34% had testosterone levels below the normal range, only six patients had a low free testosterone index with one testis still in situ; 18 patients have fathered children after chemotherapy. Approximately half of the patients completed a psychosexual questionnaire and some 30% of them admitted to sexual problems which they attributed to their treatment. Long-term sequelae of cisplatin-based chemotherapy for testicular malignancy are frequent and persistent, and follow-up of these patients should include prospective measurement of changes in blood pressure.

Parotid metastases from carcinoma of the breast

Two patients are described in whom a parotid metastasis occurred 10 years after initial treatment for carcinoma of the breast. The parotid is a very unusual site of metastasis and in both patients it was only one detectable. Parotidectomy with post-operative radiotherapy is advocated in this situation not only to obtain local tumour control but to exclude a primary parotid tumour.

Cefotaxime in the treatment of infections of the skin and skin structure

In a series of open, noncomparative studies, cefotaxime was given to 360 hospitalized patients with bacterial wound infections such as cellulitis, abscesses, or necrotizing ulcers of the skin or subcutaneous tissues. The drug was administered intramuscularly or intravenously in a mean dosage of 4 g per day (range, 1.4-12.0 g per day) in three or four equal doses for at least five days. Clinical response to therapy could not be evaluated for 100 patients, and bacterologic response could not be evaluated for 145 patients. Clinical response was satisfactory in 93.5% of the 260 patients for whom therapy could be evaluated, and bacterial response was satisfactory in 84% of the 225 patients for whom therapy could be evaluated. These rates of response include both single- and multiple-pathogen infections. There were nine instances of superinfection.