The disposition of carboplatin in ovarian cancer patients

Summary Carboplatin was given as a 30-min infusion to 11 ovarian cancer patients at doses of 170–500 mg/m². The ages, weights, and creatinine clearances (Cl_cr) ranged from 44 to 75 years, from 44 to 74 kg, and from 32 to 101 ml/min, respectively. Plasma, plasma ultrafiltrate (PU), and urine samples were obtained at appropriate times for 96 h and were analyzed for platinum. The PU and urine were also analyzed for the parent compound by HPLC. In patients with a Cl_cr of about 60 ml/min or greater, carboplatin decayed biexponentially with a mean t_1/2 of 1.6 h and a t_1/2 of 3.0 h. The mean (±SD) residence time, total body clearance, and apparent volume of distribution were 3.5±0.4 h, 4.4±0.85 l/h, and 16±31l, respectively. C_max and AUC_inf values increased linearly with dose, and the latter values correlated better with the dose in mg than in mg/m². No significant quantities of free, ultrafilterable, platinum-containing species other than the parent compound were found in plasma, but platinum from carboplatin became protein-bound and was slowly eliminated with a minimal t_1/2 of 5 days. The major route of elimination was excretion via the kidneys. Patients with a Cl_cr of 60 ml/min or greater excreted 70% of the dose as the parent compound in the urine, with most of this occurring within 12–16 h. All of the platinum in 24-h urine was carboplatin, and only 2%–3% of the dosed platinum was excreted from 48 to 96 h. Patients with a Cl_cr of less than about 60 ml/min exhibited dose-disproportional increases in AUC_inf and MRT values. The latter were inversely related to Cl_cr (r=-0.98). Over a dose range of 300–500 mg/m², carboplatin exhibited linear, dose-independent pharmaco-kinetics in patients with a Cl_cr of about 60 ml/min or greater, but dose reductions are necessary for patients with mild renal failure.Supported in part by CA 16087, CRC-RR-96, AIFCR     

Metabolism and disposition of benzidine in the dog

The dog is an animal model for assessing aromatic amine-induced bladder cancer. For this reason, metabolism and disposition of benzidine in dog was assessed. Dogs were administered a 1 mg/kg i.v. dose of [3H]benzidine (16.4 mCi/mmol). The plasma t1/2 of the radiolabeled material (benzidine plus metabolites) was significantly longer (approximately 3 h) than authentic benzidine (less than 30 min). During the 5 h experiment, the majority of radiolabel was associated with bile, urine and carcass. Bladder transitional epithelium exhibited a consistently higher concentration of bound radioactivity than bladder muscle. A significant amount of binding was observed in DNA from liver, kidney and bladder. DNA from bladder transitional epithelium exhibited the highest concentration of radioactivity. Approximately 30% of the radioactivity recovered following HPLC of urine or bile was identified as unmetabolized benzidine. 3-Hydroxybenzidine was a major metabolite identified in bile (8%) but not urine. Urine samples treated with acid, base or sulfatase yielded 3-hydroxybenzidine (6%) as a major hydrolysis product. Similar treatment of bile samples did not result in increased amounts of 3-hydroxybenzidine. Neither N-acetylated nor N-methylated metabolites of benzidine were observed in urine or bile. Thus, considerable metabolism of benzidine occurs in dogs by pathways that are yet to be determined.     

Effect of whole body hyperthermia on carboplatin disposition and toxicity in dogs

Fifty dogs with refractory or disseminated spontaneous tumours were evaluated in two independent phase I studies using either carboplatin (CBDCA) alone or CBDCA plus whole body hyperthermia (WBH). CBDCA was administered as a 30 min infusion at the onset of the plateau phase of WBH in dogs receiving combined treatment. Serum samples were collected and drug disposition was determined in both treatment groups. The dose-effect relationship was mathematically described with a logistic regression model developed from categorical toxicity data accumulated throughout the first two treatment courses in all dogs. The maximum tolerated dose (MTD) was defined as that dose which resulted in a 50% probability of achieving moderate or severe toxicity. The only toxicities observed were neutropenia and thrombocytopenia, which were dose-dependent. The nadir occurred between 7 and 14 days following treatment. A significant decrease in the area under the serum CBDCA versus time curve for dogs undergoing WBH was consistent with increased tissue binding of the drug as well as increased urinary eliminations. Serum AUC values determined following the first course of treatment were predictive of subsequent toxicity in both treatment groups. The MTD (95%CI) for CBDCA and CBDCA/WBH were estimated to be 318(44) and 239(51) mg/M² respectively (p = 0–08). A randomized phase II evaluation should be initiated to determine if a therapeutic gain can be achieved using combined CBDCA and WBH. Further refinement of the CBDCA dose in such a trial should be based on both pharmacokinetic parameters and normal tissue response.     

Disposition and metabolism of the antitumor glycoside phyllanthoside in mouse and beagle dog

Summary Phyllanthoside is a naturally occurring glycoside with activity against IP transplantable murine tumors. Phyllanthoside administered IV, to mice at a nontoxic dose of 16 mg/kg could not be detected in blood or plasma even 30 s after administration. There was rapid formation of a less polar metabolite, which disappeared with a half-life of about 10 min. When phyllanthoside was administered as an IV bolus to beagle dogs at doses of 0.1, 0.5, and 3.0 mg/kg the mean half-life of phyllanthoside elimination from plasma was 1.3 min and total body clearance 85.8 ml min^-1 kg^-1. A second phase of elimination was seen but could not be accurately defined. Only trace amounts of the less polar metabolite were detected in dog plasma. Infusion of phyllanthoside to beagle dogs at doses of 0.5 and 3.0 mg/kg over 70 min gave values for an initial half-life of 0.3 and 0.6 min, a terminal half-life of 99.4 and 16.5 min, and a total body clearance of 11.2 and 49.2 ml min^-1 kg^-1, respectively. The highest nontoxi dose of phyllanthoside in dog was 0.1 mg/kg, while doses of 0.5 mg/kg and 3.0 mg/kg resulted in ataxia and death of the dog. There was no difference in toxicity to dog according to whether phyllanthoside was given by IV bolus or continuous infusion. Isolated hepatocytes from rat metabolized phyllanthoside at a rate of 4.4 g/min per 10⁶ cells to form the less polar metabolite. Coculture with isolated hepatocytes decreased the cytotoxicity of phyllanthoside to A204 human rhabdomyosarcoma cell line growing in soft agarose. It is suggested that rapid metabolism of phyllanthoside in mouse as against dog might account for the lower toxicity of phyllanthoside in mouse, and might also account for the reported poor antitumor activity of IV-administered phyllanthoside in the mouse.The work described in this paper was supported by NCI contract no. NO1-CM-37601Preclinical Pharmacology Studies on Phyllanthoside (NSC 328426), National Cancer Institute, Bethesda, Md, USA (Dr J. A. R. Mead, personal communication November 21, 1984     

Disposition and metabolism of the antitumor agent pyrazine-2-diazohydroxide in mouse and beagle dog

Summary The pharmacokinetics and metabolism of pyrazine-2-diazohydroxide have been studied in the beagle dog and mouse. When pyrazine-2-diazohydroxide was administered to beagle dogs at a dose of 18.6 mg/kg (428 mg/m²) by i. v. bolus, the plasma half-life (t1/2) was 7.3 min, the apparent volume of distribution (V_d) 577 ml/kg, and the total body clearance (Cl) 55 ml/min per kg. In mice given pyrazine-2-diazohydroxide by i. v. bolus at 100 mg/kg (428 mg/m²), the t1/2 was 5.8 min, the V_d 250 ml/kg, and the Cl 30 ml/min per kg. When [2-¹⁴C]pyrazine-2-diazohydroxide was infused i. v. to mice at 100 mg/kg over 8 h, the Cl for parent drug was 122 ml/min per kg. The major product formed from pyrazine-2-diazohydroxide was 2-hydroxypyrazine, which accounted for 80% of the total radioactivity in the plasma after a 6-h drug infusion. These were three other metabolites in plasma, two more polar than pyrazine-2-diazohydroxide, which accounted for 7% of the radioactivity, and one less polar, which accounted for 5% of the radioactivity. Following an i. v. bolus dose of [2-¹⁴C]pyrazine-2-diazohydroxide, 79% of the radioactivity was excreted in the urine in 24 h, 3% in the feces, and 0.4% in the expired air; 18% remained in the carcass. The liver and kidney showed the highest tissue levels of radioactivity. 2-Hydroxypyrazine accounted for 45% of the urinary radioactivity, pyrazine-2-diazohydroxide for 14%, and a glucuronide or sulfate conjugate of 2-hydroxypyrazine for 17%. Twenty-four percent of the radioactivity eluted near the void volume on high-performance liquid chromatography and was not identified.The work reported in this paper was supported by NCI contract CM67904     

Single inhalation exposure to 90SrCl2 in the beagle dog: late biological effects

Late-occurring biologic effects were studied in beagle dogs that were given graded levels of 90SrCl2 via single brief inhalation exposures and were subsequently observed for their life-span. Due to the soluble chemical form of the aerosol, 90Sr was rapidly translocated from lung and deposited in bone where it was subsequently retained for a long period of time. Radiation-induced lesions were confined to the bone, bone marrow, and adjacent soft tissue. Forty-five primary bone tumors occurred in 31 of 66 exposed dogs. Metastasis occurred from 21 tumors, with the lung being the most frequent site of metastasis (76%). Twenty-seven tumors were classified as different subtypes of osteosarcoma, 14 as hemangiosarcomas, 3 as fibrosarcomas, and 1 as a myxosarcoma. Four carcinomas arising from soft tissues adjacent to bone were also considered to be 90Sr induced. In contrast to bone tumors arising in beagles chronically exposed to 90Sr through ingestion, histologic lesions of radiation osteodystrophy were minimal in this study, indicating that these lesions are not a necessary precursor of osteosarcoma development. The incidences of hemangiosarcomas (31%) and telangiectatic osteosarcomas (11%) in addition to osteosarcomas suggest that the cell of origin for all of these neoplasms is a multipotent mesenchymal cell with the potential for various morphologic expressions dependent on local environmental factors.     

Effect of tumor presence on cisplatin and carboplatin: disposition in the isolated,perfused tumor and skin flap

The purpose of this study was to evaluate the disposition of elemental platinum (Pt) derived from cisplatin (CDDP) or carboplatin (CBDCA) in the isolated, perfused tumor and skin flap (IPTSF). Flaps were perfused with either 3.0 g CDDP/ml perfusion medium (n=4 tumor,n=4 control) or 15 g CBDCA/ml (n=4 tumor,n=3 control) at a rate of 1 ml/min for 3 h. A 2-h (CDDP experiments) or 3-h (CBDCA experiments) washout phase using undosed medium was then performed. The disposition kinetics of free (ultrafilterable) Pt were characterized using a four-compartment physiologically relevant pharmacokinetic model. A tumor effect on the disposition of Pt was noted in that the Pt mass from CDDP in the central and mobile tissue compartments was greater in tumor flaps than in control flaps (P<0.05). Similar trends were noted in CBDCA-treated flaps, but these were not significant. The Pt mass in the fixed tumor and non-tumor tissue compartments was significantly greater when Pt was derived from CDDP than when it was derived from CBDCA (P<0.05). A linear relationship existed between the estimated micrograms of Pt in the flaps from both CDDP and CBDCA and the cross-sectional vascular resistance of the flaps at 30 (CDDP,r=0.78; CBDCA,r=0.89) and 60 min (CDDP,r=0.65; CBDCA,r=0.85) of perfusion. We conclude that the IPTSF is a useful model for evaluating the disposition of Pt drugs in tumor and non-tumor tissue and that tumor presence alters the disposition of CDDP.This work was supported in part by grants 08822 and 43745 from the National Cancer Institute. Its contents are solely the responsibility of the authors and do not necessarily represent the official news of the National Cancer Institute     

Preclinical pharmacologic studies of the new antitumor agent carmethizole (NSC-602668) in the mouse and beagle dog

Summary The chemical breakdown of carmethizole [1-methyl-2-methylthio-4,5-bis-(hydroxymethyl)imidazole-4,5-bis(N-methylcarbamate)hydrochloride] and its pharmacokinetics in the mouse and beagle dog were studied. Carmethizole was relatively unstable in aqueous media, having a half-life of 1 h in 0.9% sodium chloride, human whole blood, human plasma, and dog urine at 37°C. Its major breakdown product in 0.9% sodium chloride and pH 5.0 sodium phosphate buffer was carmethizole diol. When carmethizole was added to pH 7.0 or pH 9.0 sodium phosphate buffer, the major breakdown product was carmethizole diol-4-monophosphate. Carmethizole reacted directly with glutathione at pH 8.0, forming a glutathione adduct of carmethizole monocarbamate. Elimination of the drug from the plasma of the beagle dog following i.v. bolus doses of 22.4 and 4.3 mg/kg was biphasic. At these doses the terminal half-life was 39 and 46 min, respectively, and the respective total body clearance was 4.6 and 7.7 ml/min per kg. The 22.4 mg/kg dose was lethal to the beagle dog by day 4. Elimination of carmethizole from the plasma of mice following an i. v. bolus dose of 115 mg/kg was monoexponential, with a half-life of 11.6 min and a total body plasma clearance of 43.6 ml/min per kg. When the drug was infused at 230 mg/kg over 8 h into mice, the total body clearance was 40.8 ml/min per kg. Following the i.v. bolus administration of carmethizole to mice, 30% of the total dose was excreted in urine over 3 h as carmethizole diol, 10%, as carmethizole diol-sulfate, 3.4%, as carmethizole 4-monocarbamate, and 2.4%, as unchanged drug.     

Pharmacokinetics and metabolism of the antitumor agent sulfamic acid 1,7-heptanediyl ester (sulfamic acid diester) in the mouse and beagle dog

Summary The pharmacokinetics and metabolism of sulfamic acid diester were studied in the beagle dog and mouse. Elimination of sulfamic acid diester from the plasma and whole blood following i.v. administration at a dose of 193 mg/m² was best approximated by a three-compartment model in both species. The compound was relatively rapidly cleared from the plasma, with a plasma beta half-life of 2.3 h and 0.9 h and a gamma half-life of 16 h and 3 h in the dog and the mouse, respectively. Sulfamic acid diester was taken up by blood cells and only slowly eliminated with a whole blood gamma half-life of 42 h in the dog and 32 h in the mouse. When sulfamic acid diester was infused i.v. to mice at 15 mg/kg over 8 h, the clearance for the parent drug was 13.2 ml/min kg from the plasma and 3.3 ml/min kg from the whole blood. Urine collected from mouse and dog contained the parent drug and three metabolic/breakdown products, namely, sulfamic acid 1,7-heptanemonoyl ester, sulfamic acid 3-hydroxyl-1,7-heptanediyl ester, and an unidentified product. Excretion of unchanged drug and products in mouse urine over 8 h accounted for less than 16% of the dose of sulfamic acid diester. Sulfamic acid diester did not react with glutathione in buffer, whole blood, or 100 000 g rat liver cytosol.     

Successful carboplatin desensitization in patients with proven carboplatin allergy

BACKGROUND: Carboplatin is one of the most useful and well tolerated cytotoxic drugs for gynecologic malignancies. Hypersensitivity to carboplatin is not rare among patients receiving multiple recurrent treatments with this drug. The aim of the current study was to offer a safe and convenient carboplatin desensitization strategy to patients with a proven allergic reaction to this drug. METHODS: Patients with an immediate objective allergic reaction to carboplatin were skin tested with the drug. A 6-hour carboplatin desensitization protocol was administered to the patients with a carboplatin-positive skin test on each of the following treatment courses. RESULTS: Twenty-three patients with an allergic reaction to carboplatin and a positive skin test were included in the current study. Twenty patients (86.9%) were desensitized. One patient developed a mild urticarial rash. Nineteen patients tolerated 80 desensitization courses uneventfully. CONCLUSIONS: The data presented a successful desensitization protocol for individuals with a proven allergic reaction to carboplatin. The protocol was safe and convenient and offered an effective therapeutic strategy to patients who required this drug.     

The development of gemcitabine and carboplatin in the treatment of non-small-cell lung cancer

Gemcitabine plus carboplatin is a widely used regimen for the treatment of advanced non-small-cell lung cancer (NSCLC). This two drug combination is effective, with a favorable safety profile, and is well tolerated in the outpatient setting. Gemcitabine/carboplatin prolongs survival compared with gemcitabine alone, but with greater hematological toxicity. The combination regimen appears to be superior to or equally effective as other regimens including mitomycin, ifosfamide and cisplatin (MIC), cisplatin/vinblastine, gemcitabine/paclitaxel, paclitaxel/carboplatin and gemcitabine/cisplatin. Gemcitabine combined with carboplatin is associated with more hematological toxicity, but the incidence of non-hematological toxicity is often significantly lower. Gemcitabine/carboplatin also improves patient quality of life, supporting its use in treating patients with advanced NSCLC in the outpatient setting.     

Enzymuria in carboplatin nephrotoxicity

Urinary excretion of N-acetyl-beta-glucosaminidase (NAG) is an early marker of nephrotoxicity. NAG activity was assayed by the fluorimetric method of Leaback and Walker in 17 patients treated (22 courses) with carboplatin (CBDCA, 220-550 mg/m2) before infusion and 24, 48, 72 and 96 h after. Increased excretion of NAG, a sensitive index of renal tubular damage, was observed following 10 of the 22 courses. A transient increase in plasma creatinine and/or abnormal proteinuria was observed in 6 cases. Impaired renal function prior to therapy seems to be a predisposing factor to the nephrotoxicity.     

Development of carboplatin

Carboplatin (CBDCA; commercial name: Paraplatin) is a platinum complex having 1-cyclobutanedicarboxylic acid group at the two chlorine positions of cisplatin (CDDP). In the preclinical studies, CBDCA was proved to be almost equally effective to various murine tumors compared to cisplatin. Compared to cisplatin, of which free platinum was not detected from 2 hr after administration, the free type of more than 85% of total platinum concentration remained in the blood even 8 hrs after administration. Total urine excretion at 2-4 hrs after administration of CBDCA was about 57-82%, indicating CBDCA's relative rapid urine excretion compared to CDDP. In the clinical trials in Japan, appreciable clinical responses were observed in head and neck, small cell lung, ovarian, uterine cervical cancers, testicular tumor and malignant lymphoma. The renal toxicity was considerably slight, resulting in almost no hydration during treatment. Nausea and vomiting were also slight and there were no hearing-loss and neurotoxicities. The dose-limiting factor (DLF) in the phase I study was myelosuppression. From these results, it was found that carboplatin's antitumor efficacies were almost identical with cisplatin and much less toxic than cisplatin. Carboplatin will serve as a useful antitumor drug in current cancer chemotherapy.     

The effect of age on the early disposition of doxorubicin

PURPOSE: Clinical studies indicate that anthracycline cardiotoxicity increases with patient age. This may be due to altered pharmacokinetics or pharmacodynamics. A parameter termed 'early clearance' has been shown to decrease with age in patients receiving intravenous doxorubicin. This parameter, as defined, has no immediate relationship to any physiologically based pharmacokinetic parameter. We therefore reevaluated the pharmacokinetic data to better define the relationship between doxorubicin disposition and patient age. METHODS: Four studies provided a total of 56 patients with evaluable pharmacokinetics. The volume of the central compartment, V(c), the distribution clearance, CL(d), and total body clearance, CL, were determined for each patient and regressed against age. A physiologically based pharmacokinetic (PBPK) model for doxorubicin was also used to evaluate the effects of age on doxorubicin disposition. Published blood flows associated with various patient ages were used to simulate plasma and tissue doxorubicin concentrations. The relationship between CL(d) and initial tumor regression was also evaluated. RESULTS: No correlation was found between V(c) and age ( P>0.05). A highly significant correlation was observed between CL(d) and age ( P<0.0005) and there was a mild but significant relationship between CL and age ( P<0.01). Use of the PBPK model with different age-related blood flows yielded virtually identical parameter values to the clinical data analyzed. Furthermore, relative tissue AUCs simulated in old and young patients compared well with those reported for daunorubicin disposition in young and old rats. In addition, a linear relationship was observed between initial tumor regression and CL(d). CONCLUSIONS: Initial concentrations of doxorubicin following intravenous administration are higher in the elderly due to a decrease in CL(d) rather than in V(c). On the basis of simulations with the PBPK model, the reduced CL(d) appears to be related to altered regional blood flows in the elderly, and such changes may be of clinical significance.     

The natural course of emesis after carboplatin treatment

Twenty-eight patients receiving their first cycle of carboplatin treatment (300-400 mg/m2) entered a prospective study in which the natural course and intensity of postchemotherapy emesis was evaluated. Twenty-five patients (89%) experienced nausea at some time after carboplatin treatment and twenty-three patients (82%) vomited. The median number of emetic episodes was 13.5. In the 23 patients who experienced vomiting, the mean period of latency of vomiting (time from start of carboplatin administration to onset of vomiting) was 6.25 h. The period of maximum incidence of vomiting was between 8 and 12 h (71% of patients with vomiting). Between 6 and 14 h after the start of carboplatin treatment, more than 50% of patients were continuously vomiting. Vomiting declined significantly after 24 h. According to these data, carboplatin is a severely emetic drug. Prospective antiemetic trials are necessary in order to obtain antiemetic schedules which are able to increase the tolerance to carboplatin treatment.     

紫杉醇脂质体联合卡铂与紫杉醇联合卡铂治疗卵巢癌的疗效比较

目的探讨和比较紫杉醇脂质体联合卡铂与紫杉醇联合卡铂治疗卵巢癌的疗效。方法选取2012年5月至2015年5月间收治的60例卵巢癌患者,按照随机数字表法分为研究组和对照组,每组30例。研究组患者采用紫杉醇脂质体联合卡铂治疗,对照组患者采用紫杉醇联合卡铂治疗,比较两组的疗效及不良反应。结果研究组患者的总有效率为73.3%(22/30),对照组为70.0%(21/30),差异无统计学意义(P>0.05)。研究组患者的过敏反应、白细胞减少、血红蛋白减少、血小板减少、皮疹、肌痛、胃肠道反应发生率均显著低于对照组,差异有统计学意义(P<0.05),但两组患者的脱发发生率差异无统计学意义(P>0.05)。结论紫杉醇脂质体联合卡铂治疗卵巢癌与紫杉醇联合卡铂治疗卵巢癌疗效相当,但不良反应少。     

国产卡铂的注射液与粉针剂对比的临床研究

目的：观察国产卡铂注射液的疗效及毒性,并与卡铂粉针剂比较,方法全组121例小细胞肺癌（SCLC）、非小细胞肺癌（NSCLC）及乳腺癌（BC）患者随机进入卡铂注射液组（验证组）及粉针剂组（对照组）,分别予CE、CIE及CAF方案化疗,两组所用药物及剂量完全一致。结果验证组与对照组SCLC的有效率分别为83．7％与72．2％（P＞0．05）,NSCLC分别为11．5％与22．2％（P＞0．05）,BC分别为71．4％与66．7％（P＞0．05）。两组毒性反应主要为骨髓抑制及胃肠道反应。验证组与对照组白细胞下降分别为82．4％及88．2％,血小板下降分别为42．4％与55．95,血红蛋白下降分别为61．2％与73．5％,毒性多为Ⅰ-Ⅱ度,恶心呕吐发生率分别为88．2％和91．2％,其中Ⅲ-Ⅳ度仅占9．4％与8．8％,两组间差异无显著意义。结论国产卡铂注射液疗效确切,有效率和毒性反应均与粉针剂相当,临床使用方便,价格低于同类进口药物,值得临床应用。