Pharmacokinetic/pharmacodynamic modeling and simulation of neutropenia during phase I development of liposome-entrapped paclitaxel.

PURPOSE: To evaluate the maximum tolerated dose (MTD), dose-limiting toxicities (DLT), and pharmacokinetics of liposome-entrapped paclitaxel easy-to-use (LEP-ETU) and to characterize the relationship between LEP-ETU concentrations and the time course of neutropenia in cancer patients. EXPERIMENTAL DESIGN: LEP-ETU was administered to 88 patients and 63 were evaluable for pharmacokinetic/pharmacodynamic (PK/PD) analysis following 1.5- and 3-h infusions every 3 weeks (q3w; dose range, 135-375 mg/m(2)). MTD was identified using a 3 + 3, up-and-down dose-finding algorithm. PK/PD modeling was done to describe the temporal relationship between paclitaxel concentrations and neutrophil count. Simulations assessed the influence of dose and schedule on neutropenia severity to help guide dose selection. RESULTS: The MTD of LEP-ETU was identified as 325 mg/m(2). DLTs occurring at 375 mg/m(2) consisted of febrile neutropenia and neuropathy. The C(max) and area under the plasma concentration-time curve of LEP-ETU were less than proportional with increasing dose. The PK/PD model showed that LEP-ETU inhibition of neutrophil proliferation was 9.1% per 10 mug/mL of total paclitaxel concentration. The incidence of grade 4 neutropenia increased from 33% to 42% across the dose range of 275 to 325 mg/m(2) q3w. For a dose of 110 mg/m(2) given weekly, grade 4 neutropenia was estimated to be 16% compared with 42% for the same total dose administered q3w. CONCLUSIONS: LEP-ETU can be administered safely at higher doses than Taxol. Modeling and simulation studies predict that 325 mg/m(2) LEP-ETU q3w provides acceptable neutropenic events relative to those observed at 175 mg/m(2) Taxol q3w. A 275 mg/m(2) dose may offer an improved therapeutic index.

Upper GI mucosal effects of parecoxib sodium in healthy elderly subjects.

OBJECTIVE: The aim of this study was to compare the upper GI mucosal effects of i.v. parecoxib sodium with i.v. ketorolac tromethamine and placebo in healthy elderly subjects. METHODS: This was a two-center, double-blind, randomized, placebo-controlled study. Healthy subjects aged 65-75 yr who were shown at baseline endoscopy to have no gastric or duodenal lesions received either parecoxib sodium 40 mg b.i.d. for 7 days, ketorolac 15 mg q.i.d. for 5 days, or placebo for 7 days. Endoscopy was repeated at the end of dosing. Measures of upper GI effects were: 1) ulceration, 2) incidence of an ulcer and/or any erosions, and 3) incidence of an ulcer and/or > or = 11 erosions in the stomach, duodenum, or both. RESULTS: No gastric or duodenal ulcers occurred in any subjects receiving parecoxib sodium (n = 29) or placebo (n = 32). In contrast, seven (23%) of the 31 ketorolac subjects had at least one ulcer; five (16%) had gastric ulcers, and two (6%) had duodenal ulcers (p < 0.05 vs parecoxib sodium and placebo for gastroduodenal ulcers and for gastric ulcers). A total of 28 (90%) ketorolac subjects had an ulcer or at least one erosion in the stomach, compared with incidences of four (14%) and two (6%) for parecoxib sodium and placebo, respectively. Incidences of duodenal ulcers/erosions were 45% (n = 14) for ketorolac, 10% (n = 3) for parecoxib sodium, and none for placebo. The differences between ketorolac and both other treatment groups were statistically significant for both stomach and duodenum. No parecoxib sodium or placebo subjects had an ulcer or > or = 11 erosions in the stomach, compared with eight (26%) ketorolac subjects (p < 0.05 vs both parecoxib sodium and placebo). No subject in any group had > or = 11 duodenal erosions. CONCLUSIONS: These results indicate that multiple dose administration of parecoxib sodium is safe and well tolerated in healthy elderly subjects, with a decreased risk of gastroduodenal mucosal injury compared with ketorolac.

A clinical trial demonstrates the analgesic activity of intravenous parecoxib sodium compared with ketorolac or morphine after gynecologic surgery with laparotomy.

OBJECTIVE: The purpose of this study was to compare the analgesic activity of 2 doses of parecoxib sodium, ketorolac, and morphine with placebo after gynecologic surgery that requires laparotomy. STUDY DESIGN: In a randomized, controlled, double-blind, parallel-group study, 208 patients, after surgical hysterectomy, received single-dose intravenous placebo, parecoxib sodium 20 mg or 40 mg, ketorolac 30 mg, or morphine 4 mg followed by multiple-dose parecoxib sodium or ketorolac as needed. Primary efficacy variables were time to onset of analgesia, pain intensity differences, pain relief, time to first rescue/remedication, and global evaluation of study medication. RESULTS: Single-dose parecoxib sodium 40 mg provided significantly better pain responses to placebo or morphine 4 mg and was comparable to ketorolac 30 mg. Multiple-dose parecoxib sodium 20 mg, 4 times daily, or 40 mg, twice daily, was comparable to ketorolac 30 mg, 4 times daily. Parecoxib sodium was well tolerated. CONCLUSION: Parecoxib sodium is an effective analgesic in the management of acute postoperative pain after laparotomy surgery.

Efficacy and safety of intravenous parecoxib sodium in relieving acute postoperative pain following gynecologic laparotomy surgery.

BACKGROUND: This study tested the hypothesis that an injectable cyclooxygenase (COX)-2-specific inhibitor will be at least as effective and well tolerated as a COX-nonspecific conventional nonsteroidal antiinflammatory drug (NSAID) by comparing the analgesic efficacy and tolerability of one intravenous dose of parecoxib sodium, an injectable prodrug of the novel COX-2-specific inhibitor, valdecoxib, with ketorolac and placebo in postoperative laparotomy surgery patients. Intravenous morphine, 4 mg, was studied as a positive analgesic control. METHODS: In this multicenter, double-blinded, placebo-controlled study, women experiencing moderate-to-severe pain on the first day after abdominal hysterectomy or myomectomy received one intravenous dose of parecoxib sodium, 20 or 40 mg, ketorolac, 30 mg, morphine, 4 mg, or placebo. Analgesic efficacy and tolerability were evaluated for 24 h postdose or until patients, whose pain was not adequately controlled, opted to receive rescue analgesia. RESULTS: Two hundred two patients were enrolled. All treatment groups had comparable demographics and baseline pain status. All active treatments had an equally rapid time to onset of analgesia (10-23 min). Overall, each parecoxib sodium dose and ketorolac were significantly superior to morphine and placebo for most measures of analgesic efficacy at most time points, including a significantly longer (two- to threefold) time to rescue analgesia (P