Human dolasetron pharmacokinetics: II Absorption and disposition following single-dose oral administration to normal male subjects

Dolasetron is a 5-hydroxytryptamine antagonist active at type III receptors; it is presently undergoing clinical evaluation for the reduction/prevention of cancer chemotherapyinduced nausea and vomiting. A previous study demonstrated that following intravenous administration to healthy male subjects, dolasetron disappeared extremely rapidly from plasma, and less than 1 per cent of the dose appeared in the urine. A major plasma metabolite, reduced dolasetron, peaked rapidly in the plasma. In this study, dolasetron was administered orally to healthy male subjects at doses ranging from 50 to 400 mg (mesylate monohydrate). Plasma concentrations of dolasetron were low and sporadic, and there was little excreted in urine; this prevented dolasetron pharmacokinetic analysis. Reduced metabolite concentrations peaked rapidly, with a median value of 1.00 h. The median terminal disposition half-life was 7.80 h. Median values for fraction of dose excreted in urine and renal clearance were 22.2 per cent and 2.56 ml min^?1 kg^?1. Whereas areas under the plasma concentration—time curves were proportional to dose, renal clearance increased with dose (p < 0.05). However, given dose proportionality to AUC, this is probably of little therapeutic consequence. Since reduced dolasetron has significant anti-emetic activity in the ferret model, it appears that this metabolite may play a significant role in pharmacodynamic activity.     

A randomized,double-blind comparison of single-dose and divided multiple-dose dolasetron for cisplatin-induced emesis

 Purpose: Intravenous dolasetron has been shown to be an effective antiemetic agent in patients receiving high-dose cisplatin-containing chemotherapy. Previous studies have suggested that 1.8 mg/kg is an optimal dose for achieving control of emesis and nausea. The objective of this study was to compare the efficacy and safety of a single intravenous (IV) dose of dolasetron with an equal divided multiple dose. Methods: In this randomized, double-blind, parallel-group, multicenter study, the efficacy and safety of a single 1.8-mg/kg dose of dolasetron given 30 min prior to high-dose cisplatin (≥80 mg/m²) chemotherapy was compared with the same total amount of dolasetron administered in three separate doses (0.6 mg/kg each) over a 12-h interval commencing 30 min prior to beginning chemotherapy and ending 11.5 h later. Antiemetic efficacy, safety, and tolerability were compared in 55 patients with various malignancies during the 24 h following the initiation of chemotherapy. The number of emetic episodes was the primary efficacy parameter. Results: A single IV dose of dolasetron was generally more effective than a multiple-dose regimen in all measures of efficacy. There was a larger proportion of complete responders in the single-dose group compared with the multiple-dose group (48% vs 23%), although this difference did not reach statistical significance. Compared with the multiple-dose group, patients who received a single dose of dolasetron had a significantly (P=0.034) longer median time to the first emetic episode (10.1 h vs >24 h, respectively). Overall, 53% of patients had either a complete response or a major response to dolasetron, and only 40% of the total patient population received escape antiemetic medication in the 24 h after cisplatin administration. Except for headache, adverse events were similar with both regimens and were generally of mild or moderate intensity; no serious adverse events occurred. Neither dolasetron treatment regimen was associated with any clinically important events, trends in laboratory variables, or differences in safety profile. Conclusions: single-dose dolasetron was well tolerated and effectively controlled emesis and nausea in patients who received highly emetogenic, high-dose cisplatin chemotherapy. The greater antiemetic efficacy of a single prophylactic dose of dolasetron offers both convenience and potential cost savings, compared with a multiple-dose schedule of administration. Received: 31 March 1995/Accepted: 20 October 1995     

Rationale for the use of a single fixed intravenous dolasetron dose for the prevention of cisplatin-induced nausea and vomiting

Dolasetron mesilate is a selective 5-HT₃ receptor antagonist that prevents chemotherapy-induced and postoperative nausea and vomiting. For the majority of patients in intravenous dolasetron trials for chemotherapy-induced nausea and vomiting, dosing has been based on body weight (mg/kg). The approved weight-based dose is 1.8 mg/kg based on results of controlled clinical trials. However, trials of dolasetron evaluating oral doses for prevention of chemotherapy-induced emesis, and intravenous doses for prevention and treatment of postoperative emesis have used a fixed milligram dose. To identify an appropriate intravenous fixed milligram dose for the prevention of chemotherapy-induced nausea and vomiting, this analysis was performed to derive efficacy results for fixed milligram doses from pooled results obtained with dosing based on body weight. Intravenous dolasetron doses for 1,598 patients treated on a mg/kg basis (0.3, 0.6, 1.2, 1.8, 2.4, 3.0 and 5.0 mg/kg) in 14 clinical trials were converted to fixed milligram doses based on weight. Fixed-dose groups were established at doses of 50, 75, 100, 125, 150, and 200 mg. Doses less than or equal to the midpoint between two dose groups were included in the lower dose group. Pooled results showed that the 100 mg intravenous dolasetron dose group (who received actual doses of 88–112 mg) produced the highest rate (53%) of complete response (0 emetic episodes and no rescue medication in the 24-h period following initiation of chemotherapy).     

Granisetron vs dolasetron for acute chemotherapy-induced nausea and vomiting (CINV) in high and moderately high emetogenic chemotherapy: an open-label pilot study

SUMMARY

Objective: Comparative studies examining the use of oral serotonin type 3 (5-HT₃) receptor antagonists for the management of acute chemotherapy-induced nausea and vomiting (CINV) are limited. Therefore, we performed an experiential open-label pilot study at Stony Brook Hospital to allow clinicians to make informed formulary decisions at our institution and to stimulate further study. Specifically, the objective of this study was to compare the effectiveness of oral granisetron versus oral dolasetron for prophylaxis of acute CINV.

Research Design and Methods: The study was conducted during the period of 1 February 2001 to 31 March 2001. Patients (n = 26) with lymphoma or malignancies of the lungs, larynx, or uterus undergoing moderately high and highly emetogenic chemotherapy were studied. Patients admitted during February (n = 13) were administered a single oral dose of 100?mg of dolasetron; those admitted in March (n = 13) received a single oral dose of 2?mg of granisetron. All patients were administered intravenous dexamethasone 20?mg before the initiation of chemotherapy.

Main Outcome Measures: Patients were monitored for at least 24?h by clinicians. The data recorded for each patient included age, sex, the number of episodes of nausea and emesis, the intensity of nausea (when applicable), and the number of doses of rescue antiemetic medication administered (when applicable).

Results: Overall, granisetron provided significantly greater control of acute CINV than dolasetron. More patients treated with granisetron experienced total control of nausea and vomiting (69.2 vs 23.1%, p < 0.05). Fewer granisetron-treated patients experienced emesis (7.7 vs 53.8%, p < 0.05) and nausea (30.8 vs 76.9%, p < 0.05). Of those patients who experienced nausea, intensity was significantly less with granisetron than with dolasetron (?p < 0.05). Consequently, a significantly greater proportion of patients treated with dolasetron required a rescue antiemetic and significantly more doses of rescue antiemetics (both p < 0.01).

Conclusions: These data suggest that oral granisetron may demonstrate improved CINV outcomes compared with oral dolasetron in patients undergoing moderately high and highly emetogenic chemotherapy.     

甲磺酸多拉司琼与地塞米松磷酸钠在两种输液中的配伍稳定性考察

目的：考察甲磺酸多拉司琼与地塞米松磷酸钠在两种输液中的配伍稳定性。方法：模拟临床操作,在室内室温（25℃）不避光环境下,临床常用量甲磺酸多拉司琼与地塞米松磷酸钠分别在5%葡萄糖注射液（5%GS）和0.9%氯化钠注射液（NS）中配伍,在0 h（配制后5 min内）、3、6、24 h对配伍液的物理稳定性（外观、不溶性微粒）、化学稳定性（pH值、浓度）进行考察。结果：配伍液在24 h内保持无色、澄清,未见气泡、絮状物和沉淀产生,不溶性微粒、pH值与配伍液中两药浓度变化符合配伍要求,且色谱图均未发现异常色谱峰。结论：在室内室温（25℃）不避光时,甲磺酸多拉司琼注射液和注射用地塞米松磷酸钠于100 mL 5%GS或0.9%NS中,24 h内配伍稳定。     

Human dolasetron pharmacokinetics: I. Disposition following single-dose intravenous administration to normal male subjects.

Dolasetron is a 5-hydroxytryptamine antagonist active at type III receptors; it is presently undergoing clinical evaluation for the reduction/prevention of cancer chemotherapy-induced nausea and vomiting. Following intravenous administration to healthy male subjects of doses ranging from 0.6 to 5 mg kg-1, dolasetron disappeared extremely rapidly from plasma; concentrations were generally measurable for only 2-4 h. Less than 1 per cent of the dose was excreted intact in urine. A major plasma metabolite, reduced dolasetron, peaked rapidly at approximately 0.625 h (median). Its median terminal disposition half-life was 7.56 h; median values for fraction of dose excreted in urine and renal clearance were 31.0 per cent and 2.68 ml min-1 kg-1, respectively. Over the dose-range covered, pharmacokinetics of both dolasetron and reduced metabolite appeared to be independent of dose. The median ratio of the areas under the plasma concentration-time curves for metabolite relative to dolasetron was 11.9. As a result of its activity and significant plasma concentrations, reduced dolasetron may play a significant role in pharmacodynamic activity.     

HPLC-MS法测定甲磺酸多拉司琼原料药中有关物质和异构体含量

目的:建立甲磺酸多拉司琼原料药中有关物质和异构体含量测定的方法。方法:采用高效液相色谱-质谱法测定3批甲磺酸多拉司琼原料药中的有关物质和异构体含量。色谱柱为shim-packVP-ODS;流动相A为0.01mol·L-1甲酸铵溶液(用三乙胺调m节inp-H1;至检7测.0)波-乙长腈为(29150∶5n)m,。流质动谱相条B件为采0.0用1电mo喷l.雾L-电1甲离酸源铵(E溶S液I)(、正用离三子乙检胺测调节模式pH。至结7果.0):-有乙效腈(分2离7∶了73)甲,磺梯酸度多洗拉脱司,流琼速与为有1关.0物mL质.及异构体(R>1.5),甲磺酸多拉司琼的最低检测限为0.5ng,3批样品中单个杂质含量≤0.05%,总杂质含量<0.1%,异构体未检出。结论:本方法准确、专属性好,适用于甲磺酸多拉司琼原料药中有关物质和异构体的检测。     

A double-blind,placebo-controlled trial of i.v. dolasetron mesilate in the prevention of radiotherapy-induced nausea and vomiting in cancer patients

The aim of this work was to measure the safety and efficacy of single i.v. doses of dolasetron mesilate for the control of emesis caused by single high-dose (at least 6 Gy) radiotherapy to the upper abdomen. The double-blind, placebo-controlled, multicenter study stratified patients on the basis of being naive or nonnaive to radiotherapy. Patients with or without a history of previous chemotherapy were enrolled. Patients were randomized to receive placebo or 0.3, 0.6, or 1.2 mg/kg dolasetron mesilate 30 min before radiotherapy, then monitored for 24 h. Antiemetic efficacy was assessed from the time to the first emetic episode or rescue, from whether there was a complete response (0 emetic episodes/no rescue medication) or a complete-plus-major response (0-2 emetic episodes/no rescue medication), from the severity of nausea (rated by patients and the investigator), and from the investigator's assessment of efficacy. Fifty patients completed the study (owing to changing medical practice, enrollment objectives were not met; consequently, no significant linear dose trend was expected). Pooled dolasetron was superior to the placebo in its effect on the time to first emesis or rescue in radiotherapy-nonnaive patients (P=0.015). Dolasetron was statistically superior to the placebo in the overall population on the basis of a complete plus major response:54%, 100%, 93%, and 83% for the placebo and 0.3-, 0.6-, and 1.2-mg/kg doses respectively (P=0.002). The low response in the highest dose group may be due to an imbalance in the number of chemotherapynonnaive patients in that group. Dolasetron was superior to the placebo on the basis of nausea assessed by the investigator (P=0.024) and administration of rescue medication (P=0.006). Complete response at the 0.3-mg/ kg dose was superior to results with the placebo (P=0.050). Treatment-related adverse events were rare, mild to moderate in intensity, and evenly distributed across the four groups. Overall, dolasetron mesilate was effective and well-tolerated in the control of single, high-dose radiotherapy-induced emesis.     

A double-blind, multicentre comparison of intravenous dolasetron mesilate and metoclopramide in the prevention of nausea and vomiting in cancer patients receiving high-dose cisplatin chemotherapy

The potent serotonin receptor (5-HT₃) antagonists are new highly selective agents for the prevention and control of chemotherapy-induced nausea and vomiting that have been shown to be comparable to or more effective than traditional metoclopramide regimens. This study was designed to compare the antiemetic efficacy of dolasetron and metoclopramide in chemotherapy-naive and non-naive cancer patients receiving high-dose cisplatin-containing chemotherapy. This multicentre, double-blind, randomized trial compared the efficacy and safety of single i.v. doses of dolasetron mesilate salt (1.2 or 1.8 mg/kg) and metoclopramide (7 mg/kg) in 226 patients for the prevention of acute emesis and nausea associated with the administration of high-dose (80 mg/m²) cisplatin. Efficacy and safety were evaluated for 24 h. Complete responses were achieved by 57%, 48%, and 35% of patients given dolasetron mesilate 1.8 mg/kg (P=0.0009 vs metoclopramide), dolasetron mesilate 1.2 mg/kg (P=0.0058 vs metoclopramide), and metoclopramide, respectively. Overall, dolasetron was significantly more effective than metoclopramide for time to first emetic episode, nausea, patient satisfaction, and investigator global assessment of efficacy. Males, chemotherapy-naive patients, and alcoholics had higher response rates. Dolasetron was well tolerated, with mild-to-moderate headache most commonly reported. Twelve percent of patients receiving metoclopramide reported extrapyramidal symptoms compared with 0% of patients receiving dolasetron. In conclusion, dolasetron mesilate was effective for the prevention of CINV with high-dose cisplatin. Single i.v. doses of dolasetron mesilate were more effective than 7 mg/kg metoclopramide in preventing nausea and vomiting induced by highly emetogenic cisplatin-containing chemotherapy. In addition, 1.8 mg/kg dolasetron mesilate consistently produced the highest response rates and appears to be the most effective dose for further clinical development.     

Effect of casopitant, a novel NK-1 antagonist, on the pharmacokinetics of dolasetron and granisetron

Objective  The objective of this study was to characterize the impact of casopitant, a novel neurokinin-1 receptor antagonist under investigation for the prevention of postoperative and chemotherapy-induced nausea and vomiting, on the pharmacokinetics of the commonly prescribed 5-hydroxytryptamine receptor 3 receptor antagonists, dolasetron or granisetron. Materials and methods  In a phase I, open-label, two-part, two-period, single-sequence study, two cohorts of healthy subjects received either oral dolasetron (100 mg once daily for 3 days) or oral granisetron (2 mg once daily for 3 days) alone (period 1) and combined with oral casopitant, 150 mg day 1, 50 mg days 2 and 3 (period 2). Pharmacokinetics of hydrodolasetron and granisetron were assessed on days 1 and 3 of each period. Log-transformed area under the curve (AUC) and Cmax were statistically analyzed by performing an analysis of variance. Eighteen subjects were enrolled in the dolasetron cohort; nine subjects were CYP2D6 extensive metabolizers (EMs) and nine subjects were CYP2D6 poor metabolizers. Nineteen subjects were enrolled in the granisetron cohort. Results  The largest changes in hydrodolasetron exposure after coadministration with casopitant were seen in CYP2D6 EMs, with a 24% increase in hydrodolasetron AUC on day 1 and 30% increase in Cmax on days 1 and 3. All other changes in hydrodolasetron exposure were <20%, and granisetron exposure was not altered to any relevant extent (<11%). Conclusion  None of the changes observed are considered clinically meaningful, and coadministration of casopitant with dolasetron or granisetron was well tolerated. Presented as an invited lecture at the Supportive Care in Cancer MASCC/ISOO 2008 International Symposium in Houston, TX, USA on June 26–28, 2008 This work was sponsored by GlaxoSmithKline. R Stoltz received funding from GlaxoSmithKline to conduct this study. All other authors were employees of GlaxoSmithKline.