Phase II study of 254-S (cis-diammine glycolato platinum) for gynecological cancer]

A phase II study of 254-S was conducted in 134 patients with gynecological malignancies by the gynecology section of the 254-S cooperative study group. The drug was administered at least twice at a dose of 100 mg/m2 by intravenous infusion at 4 week intervals. Forty-two of the 102 evaluable patients responded, including 8 CRs and 34 PRs, with a response rate of 41.2%. The response rate was 37.7% for ovarian cancer and 46.3% for cervical cancer. The response rate of 46.3% for cervical cancer was the highest reported for any single anticancer agent available in Japan. The major side effect was hematotoxicity, in particular thrombocytopenia and leukopenia, while nephrotoxicity was rarely observed. These results suggest that 254-S is an active cisplatin analogue with reduced nephrotoxicity and is a very promising anticancer agent for the treatment of ovarian and cervical cancer.     

A phase I study of trimetrexate (NSC 352122) administered by 5-day continuous intravenous infusion

Summary Trimetrexate (TMTX) is a potent inhibitor of dihydrofolate reductase that circumvents the transport resistance seen with methotrexate and has a wide spectrum of preclinical activity. A total of 18 patients with advanced cancer were treated in a clinical and pharmacological phase I trial with TMTX given as a continuous 5-day intravenous infusion. Neutropenia, thrombocytopenia and stomatitis were the dose-limiting toxicities at the maximum tolerated dose of 50 mg/m² per 120 h (10 mg/m² per day for 5 days). There was one septic death associated with neutropenia. Other toxicities were mild rash, mild nausea and transiently raised serum transminase levels. Significant relationships between the dose given and the AUC of plasma TMTX and the steady-state plasma level were established. Significant, although weak, relationships between the percentage of change in neutrophils and platelets and both the AUC and steady-state plasma level of TMTX were also observed. No objective tumour responses were seen, although six patients had stable disease. The recommended phase II dose for a continuous infusion of trimetrexate is 40 mg/m² per 120 h.This study was supported by the AntiCancer Council of Victoria     

Phase I and pharmacokinetic study of tiazofurin (NSC 286193) administered by 5-day continuous infusion

Summary A phase I and pharmacokinetic study of tiazofurin (NSC 286193), a C-nucleoside that inhibits IMP dehydrogenase, has been completed. The drug was administered by continuous infusion over 5 days. The maximum tolerated dose was 1650 mg/m² per day, neurological toxicity being the dose-limiting factor. Gastrointestinal and hematological toxicity were mild. A definite relationship exists between dosage and steady-state levels. The plasma clearance was 29.13 (±SD 4.05) ml/min per m². No complete or partial remissions were demonstrated among the 18 patients treated at five dose levels between 550 mg/m² and 2200 mg/m² per day.     

Pharmacokinetics of cis-diammine (glycolato) platinum (254-S), a new platinum antitumor agent, following an intravenous and intraperitoneal infusion bioactive platinum concentration profile

The pharmacokinetics of cis-diammine (glycolato) platinum (254-S) was investigated in cancer patients following intravenous and intraperitoneal infusion. The serum concentrations of total and unbound 254-S were determined by bioassay and chemical assay as platinum. Platinum detected by bioassay was thought to be active and unchanged 254-S. Almost all of platinum in plasma were found to be active and unbound to protein because of no differences in the concentrations determined by bioassay and chemical assay and in plasma and plasma filtrate. In abdominal ascites, platinum concentrations determined by bioassay corresponded with those determined by chemical assay, suggesting that 254-S was stable in abdominal ascites. The Cmax and AUC of active 254-S in plasma determined by bioassay following an intraperitoneal infusion were about 60% and 60-80% of those following an intravenous infusion, respectively. These results showed that 254-S was well absorbed into systemic circulation from abdominal ascites as an active form. It is concluded that antitumor effect may be obtained following an intraperitoneal infusion of 254-S as well as for the reduction of abdominal ascites.     

A phase II clinical study of cis-diammine glycolato platinum, 254-S, for primary lung cancer]

A phase II clinical study of 254-S, a new anticancer platinum complex, for primary lung cancer was conducted by the 254-S Lung Cancer Study Group consisting of 15 institutions nation-wide. Considering the results of the phase I clinical study, 254-S was administered at 100 mg/m2 by intravenous drip infusion and this administration was repeated at least 2 times at 4-week intervals. Of 75 patients registered, 61 patients consisting of 22 with small cell lung cancer (SCLC) and 39 with non-small cell lung cancer (NSCLC) were evaluable for complete tumor response. Partial response (PR) was obtained in 17 patients, for a 27.9% response rate. The response rate for SCLC was 40.9% (9 PR in 22 patients) and that for NSCLC was 20.5% (8 PR in 39 patients). In SCLC patients with no prior chemotherapy, a 50.0% (5 PR in 10 patients) response rate was obtained. In those with prior chemotherapy, the response rate was 33.3% (4 PR in 12 patients). In NSCLC patients with no prior chemotherapy, a 22.6% (7 PR in 31 patients) response rate was obtained. In hose with prior chemotherapy, the response rate was 12.5% (1 PR in 8 patients). Major toxic effects observed were hematotoxicity such as thrombocytopenia and leukopenia, and gastrointestinal toxicity such as nausea, vomiting and anorexia. Nephrotoxicity observed was mild and infrequent in spite of the low-volume hydration performed. Based on these results, it was concluded that 254-S is a useful anticancer agent for the treatment of primary lung cancer.     

A phase II clinical study of cis-diammine glycolato platinum, 254-S, for advanced breast cancer]

A phase II clinical study of 254-S, a new anticancer platinum complex for advanced breast cancer, was conducted by the 254-S Breast Cancer Study Group consisting of 6 institutions nation-wide. Considering the results of the phase I clinical study, 254-S was administered at 100 mg/m2 by intravenous drip infusion and this administration was repeated at least 2 times at 4-week intervals. Of 19 patients registered, 16 were evaluable for tumor response (complete cases). Partial response (PR) was obtained in 2 patients, for a 12.5% response rate. Major toxic effects observed were hematotoxicity thrombocytopenia and leukopenia, and gastrointestinal toxicity (nausea and vomiting, and anorexia), though there was no case in which the treatment with 254-S had to be discontinued due to the toxic effect.     

A phase II clinical study of cis-diammine glycolato platinum, 254-S, for gastrointestinal cancers. 254-S Gastrointestinal Cancer Study Group]

A phase II clinical study of 254-S, a new anticancer platinum complex for gastrointestinal cancers, was conducted by the 254-S Gastrointestinal Cancer Study Group consisting of 16 institutions. 254-S was administered at 100 mg/m2 by intravenous drip infusion. This administration was repeated at 4-week intervals. The cases in which 254-S could be administered at least two times were regarded as complete cases evaluable for tumor response; of 75 cases registered, 53 were complete cases (29 cases with esophageal cancer, 12 with stomach cancer and 12 with colon cancer). As a result, 15 partial responses (PR) were obtained in the 29 patients with esophageal cancer and 1 PR from the 12 patients with stomach cancer, for a 51.7% and 8.3% response rate, respectively. 5 PR (55.6%) were obtained in 9 esophageal cancer patients with prior chemotherapy, including 2 PR in 4 patients previously treated with cisplatin. Major toxic effects observed were hematotoxicity including thrombocytopenia (59.0%), leukopenia (68.9%) and anemia (57.4%) and gastrointestinal toxicity such as nausea and vomiting (63.9%) and anorexia (41.0%); since grade 3 or 4 thrombocytopenia was observed with an incidence of 27.9%, careful monitoring seems to be required during the treatment with this product. Abnormal parameter changes on renal function included elevations of BUN (18.0%) and serum creatinine (9.8%). Based on these results, it was concluded that 254-S is a useful anticancer agent for the treatment of esophageal cancer.     

A phase II clinical study of cis-diammine glycolato platinum, 254-S, for cervical cancer of the uterus]

A phase II clinical study of 254-S, a new anticancer platinum complex, for cervical cancer was conducted by the 254-S Cervical Cancer Study Group consisting of 10 institutions. 254-S was administered at 80 mg/m2 by intravenous drip infusion and this administration was repeated at least 2 times at 4-week intervals, in principle. Forty of 45 patients registered, were eligible and 38 were evaluable for tumor response (complete cases). Complete response (CR) and partial response (PR) were obtained in 4 (10.5%) and 9 patients (23.7%), respectively, for a 34.2% response rate. Against squamous cell carcinoma, a 38.2% response rate (4 CR and 9 PR in 34 patients) was obtained. The response rate obtained in patients with no prior chemotherapy was 40.0% (2 CR and 8 PR in 25 patients), while that in patients with prior chemotherapy was 23.1% (2 CR and 1 PR in 13 patients). Major toxic effects observed were hematotoxicity, including thrombocytopenia (35.1%), leukopenia (73.0%), anemia (75.7%), gastrointestinal toxicity such as nausea and vomiting (83.8%) and anorexia (83.8%). Nephrotoxicity observed was in the form of an elevation of serum creatinine with an incidence of 2.7% and a decrease in creatinine clearance with an incidence of 21.7%. In comparison with the results obtained in the phase II clinical study for gynecological cancers in which 254-S was administered at 100 mg/m2, the response rate obtained in this study was slightly lower but thrombocytopenia and leukopenia observed were less frequent and milder. Based on these results, it was concluded that 254-S is a very useful anticancer agent for the treatment of cervical cancer.     

Phase I trial of 5-day continuous infusion aziridinylbenzoquinone (AZQ, diazaquone, NSC 182968)

AZQ was given to 14 patients with solid tumors in a phase I trial. Eight males and six females with a median Karnofsky performance status of 70% (range 40-90%) and a median age of 64 years (range 24-72) received 18 evaluable courses. All patients received prior chemotherapy and seven had prior irradiation. A continuous infusion for 5 consecutive days at doses of 4-8 mg/m2 per day was given every 3-4 weeks. Dose-limiting toxicity was myelosuppression, especially thrombocytopenia. No patient developed an infection while on this study. There was no evidence of cumulative toxicity in the three patients receiving two or more courses. Nonhematologic toxicity consisted only of mild nausea and vomiting in three patients and mild diarrhea in two patients. No patient experienced any mucosal, hepatic, renal, cardiac, or central nervous system toxicity. No objective antitumor responses were seen in the three patients with measurable disease who received two or more courses of AZQ. The recommended doses for phase II studies for continuous-infusion AZQ are 6 mg/m2/day X 5 repeated every 4 weeks.     

A late phase II clinical study of cis-diammine glycolato platinum, 254-S, for head and neck cancers]

A late phase II clinical study of 254-S, a new anticancer platinum complex, for head and neck cancer was conducted by the 254-S Head and Neck Cancer Study Group consisting of 31 institutions. As in the early phase II study for head and neck cancers, 254-S was administered at 100 mg/m2 by 60 min intravenous drip infusion, repeated at least twice at 4-week intervals. Of 80 cases registered, 66 were regarded as complete cases evaluable for tumor response. Complete response (CR) was observed in 7 patients (10.6%), partial response (PR) in 22 (33.3%), no change (NC) in 24 and progressive disease (PD) in 13, for a 43.9% response rate. Two CR and 11 PR (37.1% response rate) were obtained in 35 patients with prior chemotherapy, including 2 CR and 7 PR (33.3% response rate) in 27 patients previously treated with cisplatin. Of 70 patients evaluable for toxicity, side effects were observed in 60 patients (85.7%). Major toxic effects were hematotoxicity, including leukopenia (62.9%), thrombocytopenia (40.0%) and anemia (45.7%), gastrointestinal toxicity, including nausea and vomiting (64.3%), and anorexia (47.1%); grade 3 or 4 thrombocytopenia was found in 20.0% of the patients, and this toxicity was regarded as the dose limiting factor. Nephrotoxicity observed was mild and infrequent. Based on these results, it was concluded that 254-S is a very useful anticancer agent for the treatment of head and neck cancer.     

An early phase II clinical study of cis-diammine glycolato platinum, 254-S, for head and neck cancers]

An early phase II clinical study of 254-S, a new anticancer platinum complex, for head and neck cancer was conducted by the 254-S Head and Neck Cancer Study Group consisting of 10 institutions. Based on the results obtained in the phase I study, 254-S was administered at 100 mg/m2 by 60 min intravenous drip infusion after being dissolved in 300 ml of 5% xylitol. In principle, the 254-S administration was repeated at least 2 times at 4 week intervals. Hydration was performed, if needed. All 24 cases registered were regarded as complete cases evaluable for tumor response. Complete response (CR) was observed in 4 patients (16.7%), partial response (PR) in 5 (20.8%), no change (NC) in 11 and progressive disease (PD) in 4, for a 37.5% response rate. Three CR and 3 PR (40.0%) were obtained in 15 patients with prior chemotherapy, including 1 CR and 2 PR (33.3%) in 9 patients previously treated with cisplatin. Side effects were observed in 19 patients (79.2%). Major toxic effects were hematotoxicity, including thrombocytopenia (58.3%), leukopenia (58.3%) and anemia (33.3%), and gastrointestinal toxicity, including nausea and vomiting (45.8%) and anorexia (37.5%). Abnormal parameter changes on renal function were found in 2 patients (8.3%). Based on these results, it was concluded that 254-S is potentially a useful anticancer agent for the treatment of head and neck cancer, and should be further investigated in a late phase II clinical study.     

Phase I and pharmacokinetic study of 5-fluorouracil administered by 5-day continuous infusion in patients with hepatocellular carcinoma

PURPOSE: In this study the maximum tolerated dose of 5-fluorouracil administered by 5-day (120-h) continuous infusion every 4 weeks was investigated and the pharmacokinetics in patients with hepatocellular carcinoma were evaluated. METHODS: Patients with hepatocellular carcinoma no longer amenable to established forms of treatment were eligible for the study. The starting dose of 5-fluorouracil was 300 mg/m(2) per day and doses were escalated in 50 mg/m(2) per day increments in successive cohorts of three new patients if tolerated. Pharmacokinetic studies were performed at the time of the first course of therapy. RESULTS: Enrolled in the study were 20 patients. The maximum tolerated dose was 500 mg/m(2) per day and the dose-limiting toxicity was stomatitis. Other toxicities were mild and well tolerated. Age, gender and associated liver cirrhosis were significant factors influencing 5-fluorouracil clearance. With regard to biochemical parameters, serum alanine aminotransferase and cholesterol levels were correlated with 5-fluorouracil clearance. CONCLUSIONS: The maximum tolerated dose for 5-day continuous infusion of 5-fluorouracil in hepatocellular carcinoma patients was 500 mg/m(2) per day. The recommended dose for phase II studies using this schedule is 450 mg/m(2) per day. Furthermore, the pharmacokinetic data obtained in this study may be useful in determining chemotherapy dosage adjustments for reduction of toxicity.     

Phase I clinical and pharmacokinetic study of cyclophosphamide administered by five-day continuous intravenous infusion

Summary A total of 14 patients, 7 male and 7 female, received in all 21 evaluable courses of cyclophosphamide administered by 5-day continuous infusion. Cyclophosphamide doses were escalated from 300 to 400 mg/m² per day for 5 days and repeated every 21–28 days. The patient population had a median age of 55 years (range 38–76) and a median Karnofsky performance status of 80 (range 60–100). Only 1 patient had not received prior therapy; 5 patients had received only prior chemotherapy, 1 had received only prior radiotherapy, and 7 had received both. Tumor types were gastric (1), lung (2), colon (4), urethral adenocarcinoma (1), cervical (2), chondrosarcoma (1), melanoma (1), uterine leiomyosarcoma (1), and pancreatic (1). The dose-limiting toxicity was granulocytopenia, with median WBC nadir of 1700/l (range 100–4800) in 8 heavily pretreated patients treated at 350 mg/m² per day for 5 days. One patient without heavy prior treatment received two courses at 400 mg/m² and had WBC nadirs of 800/l and 600l. WBC nadirs occurred between days 9 and 21 (median 14). Drug-induced thrombocytopenia occurred in only one patient (350 mg/m² per day, nadir 85000/l). Neither hyponatremia nor symptomatic hypoosmolality was observed. Radiation-induced hemorrhagic cystitis may have been worsened in one patient. Nausea and vomiting were mild. Objective remissions were not observed. The maximum tolerated dose for previously treated patients is 350 mg/m² per day for 5 days. This dose approximates the doses of cyclophosphamide commonly used with bolus administration. Plasma steady-state concentrations (Css) of cyclophosphamide, measured by gas liquid chromatography, were 2.09–6.79 g/ml. Steady state was achieved in 14.5±5.9 h (mean ±SD). After the infusion, cyclophosphamide disappeared from plasma monoexponentially, with a t^1/2 of 5.3±3.6 h. The area under the curve of plasma cyclophosphamide concentrations versus time (AUC) was 543±150 g/ml h and reflected a cyclophosphamide total-body clearance (CL_TB) of 103±31.6 ml/min. Plasma alkylating activity, assessed by p-nitrobenzyl-pyridine, remained steady at 1.6–4.3 g/ml nor-nitrogen mustard equivalents. Urinary excretion of cyclophosphamide and alkylating activity accounted for 9.3%±7.6% and 15.1%±2.0% of the administered daily dose, respectively. The t^1/2 and AUC of cyclophosphamide associated with the 5-day continuous infusion schedule are similar to those reported after administration of cyclophosphamide 1500 mg/m² as an i.v. bolus. The AUC of alkylating activity associated with the 5-day continuous infusion of cyclophosphamide is about three times greater than the AUC of alkylating activity calculated after a 1500-mg/m² bolus dose of cyclophosphamide. Daily urinary excretions of cyclophosphamide and alkylating activity associated with the 5-day continuous infusion schedule are similar to those reported after bolus doses of cyclophosphamide.     

Phase I clinical and pharmacokinetic study of hexamethylene bisacetamide (NSC 95580) administered as a five-day continuous infusion

Hexamethylene bisacetamide (HMBA), a potent differentiating agent, was tested in patients with refractory, solid tumors. Twenty patients received 25 evaluable courses. HMBA was given by continuous i.v. infusion for 5 consecutive days with courses repeated every 4 wk, provided there was acceptable, reversible toxicity. The starting dose was 4.8 g/m2/day for 5 days with escalations in subsequent cohorts of patients to 43.2 g/m2/day for 5 days. The patients included 12 females and eight males with median age of 56 yr (range 35 to 75 yr) and a median performance status of 80% (range, 60 to 100%). All except two patients had received prior chemotherapy, radiation therapy, or both. Metabolic acidosis and neurotoxicity, consisting of agitation, hallucinations, confusion, and alteration of consciousness, were dose dependent and dose limiting. The one patient treated with 43.2 m/m2/day became acidotic, agitated, and disoriented but recovered to his previous mental and electrolyte status by 8 days after the end of the HMBA infusion. One patient treated with 33.6 g/m2/day became severely acidotic (pH 7.07) and obtunded and also developed myocardial and cerebral infarctions during the HMBA infusion. The other two patients treated with 33.6 g/m2/day became mildly agitated during drug infusion. Six patients were treated at 24 g/m2/day without neurotoxicity. Transient renal insufficiency was seen in the two patients with severe neurotoxicity and in three other patients. Dose-related, mild to moderate nausea and vomiting were observed in ten patients. Four patients developed cutaneous herpes infections during treatment. White blood cell depression was not dose related, and at 24 g/m2/day, the median white blood cell nadir was 4,500/microliter (range, 2,000 to 7,900/microliter). Thrombocytopenia was dose related. At 24 g/m2/day, the median platelet count nadir was 207,000/microliter (range, 66,000 to 542,000/microliter). No objective tumor regressions were noted. HMBA pharmacokinetics was studied at all dosages. Plasma and urine samples from 20 patients were analyzed by gas-liquid chromatography for parent compound. HMBA plasma steady-state concentrations (Css) were achieved in all patients by 12 to 24 h into infusion. Once Css was achieved, daily variation was generally less than or equal to 10% from the mean Css. HMBA plasma Css increased linearly with dose, but there was variation in the Css achieved in individual patients at each dose. Doses of 24 to 33.6 g/m2/day consistently produced plasma HMBA Css of 1 to 2 mM matching concentrations required for differentiation in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)     

Phase I and pharmacological studies of pentamethylmelamine administered by 24-hour intravenous infusion

A Phase I study of pentamethylmelamine (PMM) was conducted, administering the drug as a 24-hr i.v. infusion once weekly for 3 weeks. Doses ranged from 80 to 3000 mg/sq m/week. Twenty-six evaluable patients received a total of 30 courses of PMM. The median performance status of the patients was 60% (range, 40 to 90%), and the median age was 58 years (range, 43 to 72 years). The highest tolerated dose was 2000 mb/sq m/week. Nausea and vomiting were the dose-limiting toxicities; myelosuppression was neither consistent nor severe. One objective response lasting 10 months was noted in a patient with renal cancer. Pharmacokinetic studies using [ring-14C]PMM demonstrated a postinfusion half-life of 14C of approximately 12 hr, with the majority of the radiolabel excreted in the urine. PMM was introduced as a parenteral form of hexamethylmelamine. The present schedule does not permit administration of PMM in a dose greater than the tolerated dose of hexamethylmelamine and does not appear to offer an advantage over the p.o. use of the parent compound.     

Phase I and clinical pharmacological study of mercaptopurine administered as a prolonged intravenous infusion

The bioavailability of oral mercaptopurine (MP) is poor, and plasma levels following p.o. dosing are highly variable. In an attempt to circumvent these problems, we conducted a Phase I trial and clinical pharmacological study of MP administered as a prolonged i.v. infusion. An infusion rate of 50 mg/sq m/h, which was designed to achieve therapeutic drug levels in plasma, was used in all patients. The infusion duration was escalated in 12-h increments. Thirty-eight patients were evaluated. The dose-limiting toxicity was mucositis. Other reversible toxicities were myelosuppression and hepatotoxicity. An infusion duration of 48 h was found to be safe, unassociated with dose-limiting toxicity. Objective responses were seen in five patients. The mean plasma steady-state MP concentration achieved was 6.9 microM with little interpatient variability seen. Allopurinol coadministration had no effect on the plasma pharmacokinetics of i.v. MP. However, allopurinol did alter the urinary metabolite pattern, decreasing thiouric acid and increasing MP and thioxanthine levels. The steady-state cerebrospinal fluid:plasma ratio for MP was 0.27, suggesting that this approach may be of value in the treatment of central nervous system cancer. MP can be safely administered as a 48-h i.v. infusion at a dose rate which reliably achieves MP levels associated with optimal antileukemic activity in vitro.     

Phase I and pharmacological study of vinblastine by prolonged continuous infusion

Vinblastine is an antimitotic plant alkaloid with an elimination half-life of about 24 h. The cytotoxicity of vinblastine against solid tumor cell lines in vitro is markedly increased with prolonged exposure. Therefore, 24 patients with advanced malignancy were treated with a prolonged continuous i.v. infusion of vinblastine given via an implantable pump. The patients received vinblastine for a median of 12 wk (range, 2 to 36 wk), at dosages ranging from 0.5 to 0.9 mg/m2/day. The steady-state serum vinblastine concentration (VLBss) was determined at 2- to 3-wk intervals in each patient for correlation with toxicity. The dose-limiting toxicity was leukopenia in nine patients and peripheral neuropathy in one patient. Thirteen patients developed progressive disease prior to reaching dose-limiting toxicity, and one patient withdrew from the study because of severe local toxicity at the injection site. There was only mild toxicity at infusion rates less than or equal to 0.65 mg/m2/day, but at no dosage did reproducible toxicity occur. The maximum VLBss was significantly higher in those patients with severe leukopenia than nontoxic patients (1.91 versus 1.00 ng/ml; P = 0.001), but there was no significant difference in the maximum dosage between the two groups (0.76 versus 0.74 mg/m2/day). Our results demonstrate that prolonged infusions of vinblastine are feasible, achieving VLBss greater than 1 ng/ml, a drug concentration which is cytotoxic in vitro. The recommended starting dose of vinblastine for Phase II studies is 0.7 mg/m2/day, with dosage adjustments every 2 to 4 wk based on the white blood cell count and VLBss. Prospective monitoring of VLBss with dosage adjustment to maintain VLBss less than 1.5 to 2.0 ng/ml, may avoid the unexpected occurrence of severe myelosuppression.     

A phase I clinical and pharmacokinetic study of the dolastatin analogue cemadotin administered as a 5-day continuous intravenous infusion

Purpose: The dolastatins are a class of naturally occurring cytotoxic peptides which function by inhibiting microtubule assembly and tubulin polymerization. Cemadotin is a synthetic analogue of dolastatin 15 with potent antiproliferative and preclinical antitumor activity. This report describes a phase I study to evaluate the administration of cemadotin to adult cancer patients by a 5-day continuous intravenous (CIV) infusion. Methods: All patients had histologically confirmed refractory solid tumors. The dose was escalated from an initial level of 2.5 mg/m² (0.5 mg/m² daily) according to a modified Fibonacci algorithm. A minimum of three patients was evaluated at each dose level until the maximum tolerated dose (MTD) was established. Treatment was repeated every 21 days until patients were removed from the study due to toxicity or disease progression. Drug-related toxicities were evaluated and graded by the U.S. National Cancer Institute's Common Toxicity Criteria. A radioimmunoassay (RIA) that detected both the parent drug and its metabolites with an intact N-terminal region of the molecule was used for pharmacokinetic studies. Results: Twenty heavily pretreated patients received a total of 40 courses of cemadotin over five dose levels ranging from 2.5 to 17.5 mg/m². Reversible dose-related neutropenia was the principal dose-limiting toxicity and 12.5 mg/m² was established as the MTD. Nonhematologic toxicities attributed to the drug were moderate, and there was no evidence of the cardiovascular toxicity noted in the prior phase I studies of cemadotin given IV as a 5-min injection or 24-h infusion. There were no objective antitumor responses. Time courses of the cemadotin RIA equivalent concentration in whole blood were defined in 14 patients during the first cycle of therapy. The RIA-detectable species exhibited apparent first-order pharmacokinetics across the entire range of doses. The mean ± SD of the observed steady-state blood concentration at the 12.5 mg/m² MTD was 282 ± 7 nM (n=3). Blood levels decayed monoexponentially following the end of the infusion, with a mean half-life of 13.2 ± 4.3 h (n=14) in all patients. Mean values (n=14) of the total blood clearance and apparent volume of distribution at steady state were 0.52 ± 0.09 l/h/m² and 9.9 ± 3.3 l/m², respectively. Conclusions: The cardiotoxic effects of cemadotin were completely avoided by administering it as a 120-h CIV infusion. Thus, cardiovascular toxicity appears to be associated with the magnitude of the peak blood levels of the parent drug or its metabolites, whereas myelotoxicity is related to the duration of time that blood levels exceed a threshold concentration. Nevertheless, the data acquired during the extensive clinical experience with cemadotin requires careful examination to assess whether advancing this compound into disease-oriented efficacy studies is merited. Received: 8 November 1999 / Accepted: 28 April 2000     

Phase I/pharmacokinetic study of the topoisomerase I inhibitor GG211 administered as a 21-day continuous infusion

Background: Preclinical results support a prolonged schedule of administration for topoisomerase I inhibitors, and we have previously demonstrated the safety and activity of the novel water-soluble topoisomerase I inhibitor GG211 when given as a 72-hour continuous infusion to cancer patients.Patients and methods: In a three-center international phase I trial, 38 patients received GG211 doses from 0.3 to 0.5 mg/m2/day by continuous intravenous infusions for seven, 14, and 21 days. Patients' median performance status was 1; nearly half had colorectal cancer, and 35 patients had prior chemotherapy.Results: The first patient cohort received 0.3 mg/m2/day for seven days with no significant toxicities. Subsequent cohorts received continuous infusions for 14 and 21 days at this dose level with only mild myelosuppression noted. Dose-escalation on the 21-day schedule was then performed. No dose-limiting toxicity occurred at the 0.4 mg/m2/day dose level. Thrombocytopenia was dose-limiting with 0.5 mg/m2/day dosing but was not cumulative. Other grade 3–4 toxicities included neutropenia, nausea, vomiting, diarrhea, and fatigue. Partial responses occurred with 21-day infusion in two patients with breast and ovarian cancer at the 0.3 and 0.4 mg/m2/day dose levels, respectively. Mean GG211 lactone Css ranged from 0.17 to 0.64 ng/ml.Conclusion: The maximum tolerated dose of GG211 administered as a 21-day continuous infusion is 0.4 mg/m2/day with antitumor activity noted at tolerable doses.