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

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

The effects of food and divided dosing on the bioavailability of oral vinorelbine.

The effects of food and divided dosing on the bioavailability of a liquid-filled gelatin capsule formulation of vinorelbine (Navelbine), a semisynthetic vinca alkaloid with broad clinical activity, was evaluated in patients with advanced solid tumors. A group of 13 patients were randomized to treatment with the oral formulation at the recommended phase II dose of 80 mg/m2 per week either in the fasting state or after ingestion of a standard meal. Patients were treated 1 week later in the alternate state relative to their first dose. The effects of divided dosing were assessed during the 3rd week, at which time vinorelbine was administered in two divided doses. After the completion of pharmacokinetic and bioavailability studies, patients received the oral formulation at a dose of 80 mg/m2 per week in two divided doses to evaluate the feasibility of chronic oral drug administration. Both manipulations resulted in small, albeit statistically significant, reductions in the relative bioavailability of this oral formulation. The relative bioavailability decreased by 22 +/- 28% when treatment followed the ingestion of a standard meal, possibly due to a delay in gastrointestinal transit time. The mean time of maximum plasma concentration (Tmax) increased from 1.3 +/- 1.6 h in the fasting state to 2.5 +/- 1.6 h in the fed state, although this difference was not statistically significant. Similarly, the relative bioavailability declined by 16 +/- 51% when vinorelbine was administered in two divided doses. An analysis of dose proportionality revealed disproportionate increases in dose-normalized Cmax and AUC values with single oral doses above 120 mg, which may account for this phenomenon. The high clearance of vinorelbine, which approaches hepatic blood flow, and the lack of dose proportionality after oral administration, indicate that there is a large first-pass effect which may be saturable, or nonlinear, above single doses of 120 mg. In addition, the toxicological and pharmacological characteristics of oral vinorelbine indicate that treatment after a standard meal or on a divided dosing schedule is safe. Chronic oral administration of the agent in two divided doses was also well tolerated. However, the small reduction in the relative bioavailability following the ingestion of a standard meal and with divided dosing suggest the need for further pharmacodynamic studies to determine if reductions in drug exposure of this magnitude may portend diminished antitumor activity.

Phase I and pharmacologic studies of pyrazoloacridine, a novel DNA intercalating agent, on single-dosing and multiple-dosing schedules.

PURPOSE: To determine the maximum-tolerated doses (MTDs), principal toxicities, and pharmacologic behavior of pyrazoloacridine (PZA), a novel DNA intercalator with a unique mechanism of action, on single- and multiple-dosing schedules. PATIENTS AND METHODS: PZA was administered on a single-dosing schedule as a 1- to 3-hour infusion and on a multiple-dosing schedule as a 1-hour infusion daily for 5 days to cancer patients at doses ranging from 400 to 935 mg/m2 and 40 to 180 mg/m2/d every 3 weeks, respectively. RESULTS: On the single-dosing 1-hour schedule, CNS toxicity, characterized by neuropsychiatric and neuromotor effects, prompted prolongation of the infusion duration to 3 hours and led to a study of PZA on a multiple-dosing schedule. Both measures resulted in lower incidence of CNS toxicity. Neutropenia was the principal toxicity and precluded dose escalation to levels greater than 750 mg/m2 on the single-dosing (3-hour) schedule and 150 mg/m2/d x 5 (total dose, 750 mg/m2) on the multiple-dosing schedule. Thrombocytopenia, anemia, and nonhematologic effects occurred less frequently. Responses were observed in several patients with platinum- and taxane-refractory ovarian carcinoma; antitumor activity was also noted in patients with cervical and colorectal carcinomas. Significant intraindividual variability characterized by the presence of multiple drug peaks and troughs was observed in the pharmacologic studies. The maximal PZA concentrations achieved in both studies exceeded drug concentrations associated with significant cytotoxicity in preclinical studies and correlated with the occurrence of CNS toxicity. CONCLUSION: Neutropenia is the dose-limiting toxicity on both schedules and 750 mg/m2 and 150 mg/m2/d are the recommended starting doses of PZA on single- and multiple-dosing schedules, respectively, for minimally pretreated patients in phase II studies; slightly lower doses are recommended for more heavily pretreated subjects. The favorable toxicity profile of PZA and its antitumor activity in several refractory tumors warrant broad phase II evaluations of this agent.

Pharmacokinetic, bioavailability, and feasibility study of oral vinorelbine in patients with solid tumors.

PURPOSE: The feasibility of administering vinorelbine (Navelbine, Burroughs Wellcome Co, Research Triangle Park, NC), a semisynthetic vinca alkaloid with broad activity, as a liquid-filled gelatin capsule was evaluated in a bioavailability (F) and pharmacokinetic study. PATIENTS AND METHODS: Each of 17 cancer patients had pharmacokinetic studies performed after receiving vinorelbine 30 mg/m2 intravenously (IV), which is the maximum-tolerated dose (MTD) for weekly IV administration, and twice after receiving the oral formulation at a nominal dose of 100 mg/m2. Subsequently, these patients and 10 other subjects received the oral formulation at a dose of 100 mg/m2/wk to evaluate the feasibility of chronic oral administration. RESULTS: Plasma drug disposition was well described by a triphasic model. Mean central volume of distribution and steady-state volume of distribution (Vss) were large (0.66 +/- 0.46 L/kg and 20.02 +/- 8.55 L/kg, respectively); the mean harmonic terminal half-life (t1/2) was long (18 hours); and the high mean clearance (CI) rate (0.80 +/- 0.68 L/h/kg) approached hepatic blood flow. F was low (0.27 +/- 12), and absorption was rapid (mean time of maximum plasma concentration [Tmax], 0.91 +/- 0.22 hours). Absorption parameters after the first and second oral doses were similar, with mean F values of 0.27 +/- 0.14 and 0.25 +/- 0.11, respectively. Coefficients of variability (CVs) for F, maximum plasma concentration (Cmax), and Tmax were 32%, 42%, and 78%, respectively, indicating moderate intraindividual variability. The pharmacologic profile of this oral formulation indicates that there is a large first-pass effect. Neutropenia was the principal toxicity of oral vinorelbine. Grade 3 or 4 neutropenia occurred in 63% of patients, but only 11% developed neutropenia and infection. Nausea, vomiting, and diarrhea were also common with oral administration, but these effects were rarely severe and could be ameliorated by using a divided-dose schedule and/or prophylactic antiemetic and antidiarrheal agents. The mean nominal oral dose was 82 mg/m2, and the mean percentage of intended dose that was received was 92%. Although dose escalations were permitted for negligible toxicity, doses were not escalated to greater than 100 mg/m2/wk in any patient. Vinorelbine given as a liquid-filled gelatin capsule at 100 mg/m2 provided equivalent pharmacologic exposure as 30 mg/m2 IV. CONCLUSION: The oral administration of vinorelbine, specifically as a liquid-filled, soft gelatin capsule, is a feasible route of administration. Weekly oral dosing at 100 mg/m2 induces a consistent degree of myelosuppression, but the high frequency of grade 3 or 4 neutropenia, albeit brief and uncomplicated, warrants the recommendation of a slightly lower starting dose, ie, 80 mg/m2/d, for subsequent phase II evaluations, especially in heavily pretreated patients.

Phase I and pharmacological study of the novel topoisomerase I inhibitor 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin (CPT-11) administered as a ninety-minute infusion every 3 weeks.

7-Ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin (CPT-11; Irinotecan), a semisynthetic analogue of camptothecin (CPT) with broad preclinical antitumor activity, has demonstrated impressive activity in phase II trials in Japan in advanced small and non-small cell lung, colorectal, cervical, and ovarian carcinomas, as well as in refractory lymphomas and leukemias. In this phase I and pharmacological study, 90-min infusions of CPT-11 were administered every 3 weeks at doses ranging from 100 to 345 mg/m2 to patients with solid malignancies. Acute, severe, and refractory vomiting, diarrhea, and/or abdominal cramps associated with flushing, warmth, and diaphoresis occurred in the immediate posttreatment period at the 240-mg/m2 dose level in several patients who were not treated with premedications. The characteristics and temporal nature of these toxicities, the prompt resolution of symptoms following treatment with diphenhydramine, and the successful use of a premedication regimen consisting of ondansetron and diphenhydramine in preventing these acute effects suggest that vasoactive substances are involved in the mediation of these acute toxicities. With the routine use of these premedications, there was no single toxicity type that limited the escalation of CPT-11 doses. Instead, a constellation of severe hematological and gastrointestinal effects precluded the repetitive administration of CPT-11 at doses above 240 mg/m2, the maximum tolerated dose and recommended phase II dose on this schedule. Major responses were observed in patients with advanced colorectal, cervical, and renal cancers. The disposition of total CPT-11 in plasma was fit by a biexponential kinetic model with renal elimination accounting for 37 +/- 4% (SE) of total drug disposition. The Cmax for the active metabolite of CPT-11, 7-ethyl-10-hydroxycamptothecin (SN-38), was achieved at 2.2 +/- 0.1 h after treatment, and mean residence times for both CPT-11 and SN-38 were long, 9.1 and 10.0 h, respectively. Compared with topotecan, another CPT analogue under development, a larger proportion of total drug exposure was accounted for by the active lactone (closed-ring) forms of CPT-11 and SN-38; areas under the time-versus concentration curve for their respective lactone were 44 and 50% of areas under the time-versus-concentration curve for total CPT-11 and SN-38. Although intermittent dosing schedules appear to be superior to single dosing schedules for CPT and some CPT analogues in preclinical tumor models, the maintenance of biologically relevant concentrations of SN-38 for relatively long durations may negate the potential pharmacological benefits of intermittent and continuous administration schedules for CPT-11.(ABSTRACT TRUNCATED AT 400 WORDS)

Phase I and pharmacologic study of paclitaxel and cisplatin with granulocyte colony-stimulating factor: neuromuscular toxicity is dose-limiting.

PURPOSE: To determine the maximum-tolerated doses (MTD), the principal toxicities, and the pharmacologic behavior of high doses of Taxol (paclitaxel; Bristol-Myers Squibb, New York, NY) combined with cisplatin and granulocyte colony-stimulating factor (G-CSF). PATIENTS AND METHODS: Untreated and minimally pretreated solid-tumor patients received 24-hour infusions of Taxol on day 1 followed by cisplatin on day 2 and G-CSF, 5 micrograms/kg/d subcutaneously (SC), beginning on day 3. Treatment was repeated every 3 weeks. Starting doses of Taxol and cisplatin were 135 and 75 mg/m2, respectively. RESULTS: The development of a severe peripheral neuropathy and/or severe myalgias precluded the chronic administration of Taxol and cisplatin with G-CSF at doses greater than 250 mg/m2 and 75 mg/m2, respectively. At this dose, the mean Taxol steady-state plasma concentration (Css) exceeds concentrations capable of inducing pertinent antimicrotubule effects in vitro. The severity of the neuropathy was related to the cumulative dose of Taxol, the magnitude of the dose administered during each treatment, and the presence of a pre-existing medical disorder associated with peripheral neuropathy. A proximal myopathy of modest severity also was documented. Although severe neutropenia occurred frequently, especially at the MTD, it was rarely associated with fever (8% of courses), and absolute neutrophil counts (ANCs) less than 500/microL never persisted for more than 5 days. Responses were noted in non-small-cell lung cancer (NSCLC) and head and neck, breast, and esophageal cancers. CONCLUSION: Taxol and cisplatin doses of 250 mg/m2 and 75 mg/m2, respectively, can be administered repetitively with G-CSF to untreated and minimally pretreated patients. However, these doses are not recommended for patients with pre-existing neuropathies until additional experience in high-risk patients is obtained. Although this Taxol dose is nearly 85% higher than the dose that can be combined with cisplatin in the absence of G-CSF, this high-dose regimen should not be used outside the investigational setting until a dose-response relationship has been demonstrated for Taxol in randomized clinical trials.

Nursing considerations in paclitaxel (Taxol) administration.

The administration of paclitaxel (TAXOL) presents some challenges unique among chemotherapeutic agents. Information published and presented to date has focused primarily on the most threatening and clinically significant aspects of paclitaxel administration and resultant side effects. However, there are a number of other issues that, while not as acutely dangerous, can be very significant to the success of paclitaxel therapy and to those medical, pharmacy, and nursing personnel involved in drug administration and patient management. This review will focus on the collaborative role of the nurse in the recognition and prevention of side effects related to paclitaxel therapy. A nursing plan of care describes the pertinent paclitaxel toxicities and suggests interventions related to patient care issues.

Phase I and pharmacological study of the pulmonary cytotoxin 4-ipomeanol on a single dose schedule in lung cancer patients: hepatotoxicity is dose limiting in humans.

4-Ipomeanol (IPO), a naturally occurring pulmonary toxin, is the first cytotoxic agent to undergo clinical development based on a biochemical-biological rationale as an antineoplastic agent targeted specifically against lung cancer. This rationale is based on preclinical observations that metabolic activation and intracellular binding of IPO, as well as cytotoxicity, occurred selectively in tissues and cancers derived from tissues that are rich in specific P450 mixed function oxidase enzymes. Although tissues capable of activating IPO to cytotoxic intermediates in vitro include liver, lung, and kidney, IPO has been demonstrated in rodents and dogs to undergo in situ activation, bind covalently, and induce cytotoxicity preferentially in lung tissue at doses not similarly affecting liver or kidneys. Although the drug was devoid of antitumor activity in the conventional murine preclinical screening models, cytotoxic activity was observed in human lung cancers in vitro and in human lung cancer xenografts in vivo, adding to the rationale for clinical development. Somewhat unexpectantly, hepatocellular toxicity was the dose-limiting principal toxicity of IPO administered as a 30-min infusion every 3 weeks to patients with lung cancer. In this study, 55 patients received 254 courses at doses almost spanning 3 orders of magnitude, 6.5 to 1612 mg/m2. Transient and isolated elevations in hepatocellular enzymes, predominantly alanine aminotransferase, occurred in the majority of courses of IPO at 1032 mg/m2, which is the recommended IPO dose for subsequent phase II trials. At higher doses, hepatocellular toxicity was more severe and was often associated with right upper quadrant pain and severe malaise. Toxic effects were also noted in other tissues capable of activating IPO, including possible nephrotoxicity in a patient treated with one course of IPO at 154 mg/m2 and severe, reversible pulmonary toxicity in another patient who received nine courses of IPO at doses ranging from 202 to 826 mg/m2. Although individual plasma drug disposition curves were well described by a two-compartment first order elimination model, The relationship between IPO dose and area under the disposition curve was curvilinear, suggesting saturable elimination kinetics. At the maximum tolerated dose, the mean half-lives (lambda 1 and lambda 2) were 6.7 and 114.5 min, respectively. Renal excretion of parent compound accounted for less than 2% of the administered dose of IPO. An unidentified metabolite was detected in the plasma of patients treated at higher doses. No objective antitumor responses were observed; however, stable disease persisted for at least eight courses in 27% of patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Phase I and pharmacologic study of topotecan: a novel topoisomerase I inhibitor.

PURPOSE: A phase I and pharmacologic study was undertaken to determine the maximum-tolerated dose (MTD), describe the principal toxicities, and characterize the pharmacologic behavior of topotecan, which is a semisynthetic analog of camptothecin with broad preclinical antitumor activity and the first topoisomerase I-targeting agent to enter clinical development in the United States since studies of sodium camptothecin over 2 decades ago. PATIENTS AND METHODS: Thirty-minute infusions of topotecan were administered daily for 5 consecutive days every 3 weeks to patients with advanced solid malignancies at doses ranging from 0.5 to 2.5 mg/m2/d. RESULTS: At doses of 1.5 and 2.0 mg/m2, grade 3 and 4 neutropenia occurred in most courses; however, neutropenia was brief and rarely associated with fevers or treatment delays. Neutropenia was more severe in patients with extensive prior treatment than in minimally pretreated patients, but these differences were not substantial. At 2.5 mg/m2, topotecan induced profound and prolonged neutropenia that was frequently associated with fever and treatment delays in minimally pretreated patients. Topotecan also induced mild depressions in the hematocrit level in the majority of courses; however, precipitous drops requiring transfusional therapy occurred in 14% of courses and suggested a drug-induced hemolytic effect. Unlike sodium camptothecin, hemorrhagic cystitis was not observed. Thrombocytopenia, skin rash, diarrhea, and vomiting occurred infrequently and were modest in severity. Responses were observed in non-small-cell lung carcinoma and platinum-refractory ovarian carcinoma. Drug disposition in plasma was described by a biexponential model, with renal elimination accounting for 38.7% of drug disposition. Topotecan was rapidly hydrolyzed in vivo to a less active, open-ring form. CONCLUSIONS: Neutropenia is the dose-limiting toxicity, and 1.5 mg/m2 is the recommended starting dose of topotecan for both minimally and heavily pretreated patients in future phase II trials, with escalation to 2.0 mg/m2 if treatment is well tolerated. Non-small-cell lung and platinum-refractory ovarian carcinomas should be among those evaluated in phase II trials of topotecan.

Phase I and pharmacokinetic study of hepsulfam (NSC 329680).

Hepsulfam (NSC 329680), a bifunctional alkylating agent structurally related to busulfan, has entered clinical trial based on its broader preclinical antitumor activity compared with that of busulfan and its i.v. formulation which may circumvent the many problems arising from the p.o. administration of busulfan, such as significant individual differences in bioavailability. In this Phase I study, 53 patients received 95 courses of hepsulfam at doses ranging from 30 to 480 mg/m2 administered i.v. over 30 min every 28 days. Hematological toxicity was dose limiting. Leukopenia and thrombocytopenia were dose related, delayed in onset, and sustained for long durations. Toxicity was cumulative in most patients receiving more than one course. This pattern of myelosuppression suggests that hepsulfam is cytotoxic to hematopoietic stem cells. Although hematological toxicity was not particularly severe during most courses, its lengthly duration precluded the prompt administration of subsequent courses. Minimal nonhematological effects were observed. Pharmacokinetic studies revealed that the clearance rate of hepsulfam is linear over the dose range studied and that its plasma disposition is biphasic with mean alpha and beta half-lives of 19 +/- 18 (SE) min and 337 +/- 248 (SE) min, respectively. The area under the plasma clearance curve correlated with the percentage of change in WBC using a sigmoidal Emax model and with the duration of thrombocytopenia in patients with hematological toxicity. Based on the protracted duration of the toxicity of multiple doses that were greater than 210 mg/m2, the recommended starting dose for Phase II trials is 210 mg/m2. However, these trials should be pursued with caution because of the protracted nature of hepsulfam's myelosuppression. Because hepsulfam produced minimal nonhematological toxicity, substantial dose escalation above 480 mg/m2 may be possible with hematopoietic stem cell support.

Sequences of taxol and cisplatin: a phase I and pharmacologic study.

Untreated and minimally pretreated solid tumor patients received alternating sequences of taxol and cisplatin. Sequential dose escalation of each agent using taxol doses of 110 or 135 mg/m2 and cisplatin doses of 50 or 75 mg/m2 resulted in four dosage permutations that induced grades 3 and 4 neutropenia in 72% to 84% and 50% to 53% of courses, respectively. Neutropenia was brief, and hospitalization for neutropenia and fever was required in 13% to 24% of courses. However, further escalation of taxol to 170 or 200 mg/m2 induced grade 4 neutropenia in 79% to 82% of courses. At the highest taxol-cisplatin dose level (200 mg/m2 to 75 mg/m2), the mean neutrophil count nadir was 98/microL, and hospitalization for neutropenia and fever was required in 64% of courses. The sequence of cisplatin before taxol, which has less antitumor activity in vitro, induced more profound neutropenia than the alternate sequence. Pharmacologic studies indicated that this difference was probably due to 25% lower taxol clearance rates when cisplatin preceded taxol. Although neurotoxicity was initially thought to be a potentially serious effect of the combination, mild to modest neurotoxicity occurred in only 27% of patients. Adverse effects also included myalgias, alopecia, vomiting, diarrhea, bradycardia, and asymptomatic ventricular tachycardia. Objective responses were noted in melanoma, as well as non-small-cell lung, ovarian, breast, head and neck, colon, and pancreatic carcinomas. Based on these results, the sequence of taxol before cisplatin at doses of 135 and 75 mg/m2, respectively, is recommended for phase II/III trials, with escalation of taxol to 170 mg/m2 if treatment is well tolerated.