Effects of age and sex on the single-dose pharmacokinetics and pharmacodynamics of apixaban.

BACKGROUND AND OBJECTIVES: The effects of age and sex on apixaban pharmacokinetics and pharmacodynamics were studied. METHODS: This was an open-label, single-dose, 2 × 2 factorial study. Healthy young (aged 18-40 years) and elderly (aged ≥ 65 years) male and female subjects received a single oral 20 mg dose of apixaban. Blood and urine samples were collected for pharmacokinetic and pharmacodynamic (blood only) analyses. Subjects were monitored for adverse events throughout the study. RESULTS: Seventy-nine subjects were enrolled into four groups: young males (n = 20), elderly males (n = 20), young females (n = 20) and elderly females (n = 19). Age did not affect the maximum observed plasma concentration (C max). The mean area under the concentration-time curve from time zero extrapolated to infinite time (AUC∞) was 32% greater in elderly subjects than in young subjects. The mean C max and AUC∞ values were 18 and 15% higher, respectively, in females than in males. The time course of the mean international normalized ratio (INR), modified prothrombin time (mPT) and anti-Xa activity tracked the apixaban concentration-time curve. All three pharmacodynamic measures exhibited a positive linear correlation with the plasma apixaban concentration. Differences in the mean INR, mPT and anti-Xa activity between age and sex groups were small (<15% at the maximum mean values) and were generally related to pharmacokinetic differences. However, anti-Xa activity demonstrated less variability than the INR or mPT, and may have utility as a bioassay for apixaban. Apixaban was well tolerated, with no serious adverse events. CONCLUSION: There were no clinically meaningful age- or sex-related differences in the pharmacokinetics and pharmacodynamics of apixaban that would require dose modification on the basis of age or sex alone.

Withdrawal-related adverse events from clinical trials of clobazam in Lennox-Gastaut syndrome.

To assess withdrawal-related adverse event (AE) rates following abrupt clobazam discontinuation in Phase I trials and gradual clobazam tapering (2-3 weeks) following discontinuation from III trials met the criteria for potential/III trials, we evaluated AE data from four multiple-dosage Phase I trials (duration: 8-34 days). Therapeutic (20 and 40 mg/day) and supratherapeutic clobazam dosages (120 and 160 mg/day) were administered. Adverse events (AEs) were also assessed for patients with Lennox-Gastaut syndrome enrolled in Phase II (OV-1002) and Phase III (OV-1012) studies (duration ≤15 weeks) and in the open-label extension (OLE) trial OV-1004 (≤5 years). Potential withdrawal-related AEs were identified by preferred terms, provided that the AEs occurred ≥1 day following and ≤30 days after the last clobazam doses, or were deemed withdrawal symptoms by investigators. Clinical Institute Withdrawal Assessment for Benzodiazepines (CIWA-B) scale was used to evaluate withdrawal intensity in three of the four Phase I trials. A total of 207 participants in Phase I trials received steady-state clobazam dosages of 20-160 mg/day, 182 received clobazam dosages of ≥40 mg/day, and 94 received clobazam dosages of ≥120 mg/day. Abrupt clobazam discontinuation led to 193 withdrawal-related AEs for 68 Phase I participants. Nearly 50% of AEs occurred after discontinuation of clobazam dosages of ≥120 mg/day. Adverse events were mild or moderate and included headache (14% of Phase I participants), insomnia (12.6%), tremor (10.1%), and anxiety (8.7%). The CIWA-B scores varied (range: 0-59). Most scores were <30, indicating possible mild benzodiazepine withdrawal. III trials met the criteria for potential/III patients received clobazam dosages of ≤40 mg/day, and those in the OLE trial received clobazam dosages of ≤80 mg/day. Eighty-seven patients discontinued clobazam and were gradually tapered. No withdrawal-related AEs or incidences of status epilepticus were reported. Withdrawal-related AEs observed in Phase I studies following abrupt clobazam discontinuation at therapeutic and supratherapeutic dosages were generally mild. No withdrawal-related AEs occurred when dosages were tapered over 3 weeks, after short- or long-term clobazam use (≤5 years).

Absence of effect of telbivudine on cardiac repolarization: results of a thorough QT/QTc study in healthy participants.

The effect of telbivudine on cardiac repolarization was evaluated in healthy participants at clinical and supratherapeutic doses. Sixty-two participants were enrolled, stratified by sex, and randomized according to a crossover design among 4 treatment sequences: placebo, a single moxifloxacin 400-mg dose as positive calibrator, and telbivudine 600 and 1800 mg/d for 7 days. Intensive time-matched electrocardiogram measurements and pharmacokinetic sampling were performed at baseline and on day 7 over 24 hours. For telbivudine and moxifloxacin, time-matched, placebo-adjusted change from baseline in QT was calculated and corrected using Fridericia's formula (QTcF). While moxifloxacin produced the expected significant changes in QTcF, none of the changes in QTcF for either doses of telbivudine exceeded 5 ms, and none of the associated upper 1-sided 95% confidence intervals (CI) exceeded the limit of 10 ms. There was no increase in QTcF with increasing plasma telbivudine. The supratherapeutic dose of telbivudine was well tolerated with a safety profile similar to the clinical dose despite a 3-fold increase in plasma exposure. This study therefore met the criteria for a negative thorough QT study. Telbivudine had no adverse effect on cardiac repolarization in healthy participants, even at supratherapeutic exposure, suggesting a broad safety margin.

A randomized, double-blind, one-week study comparing effects of a novel COX-2 inhibitor and naproxen on the gastric mucosa.

CS-706 is a novel cyclooxygenase-2 (COX-2) inhibitor with potent analgesic, anti-inflammatory, and antitumor properties in animal models. This one-week, multicenter study was undertaken to assess the safety and tolerability of CS-706 and to compare the effects of CS-706 versus naproxen on acute gastrointestinal (GI) mucosal injury. Healthy men and women (n=160) without evidence of underlying gastroduodenal lesions were randomized to placebo, 100 mg CS-706 once daily, 200 mg CS-706 once daily, or 500 mg naproxen twice daily, administered for 7 days. On Day 8, subjects underwent a posttreatment upper GI endoscopy to assess development of gastroduodenal petechiae, erosions, and ulcers. Inhibition of COX-1 and COX-2 activity over the 24-hr postdose interval on Day 7 was determined in 48 subjects (12 per treatment group). CS-706 was safe and well tolerated. The extent of upper GI mucosal injury for both CS-706 dose groups was statistically significantly less than that for naproxen (P < 0.001) and was similar to placebo (P=0.615 and P=0.115 for 100 and 200 mg CS-706, respectively). No subject in placebo or either CS-706 treatment group had gastroduodenal ulcers, compared with 11 (28.2%) subjects treated with naproxen (P < 0.001). Both doses of CS-706 inhibited COX-2 activity to a similar extent as naproxen, whereas neither dose of CS-706 showed meaningful inhibition of platelet COX-1. In contrast, naproxen nearly completely inhibited COX-1 over the dosing interval. We conclude that CS-706, dosed up to 200 mg once daily, has an acute, upper GI toxicity profile similar to that of placebo and significantly superior to that of naproxen.

Parecoxib sodium demonstrates gastrointestinal safety comparable to placebo in healthy subjects.

BACKGROUND: The gastrointestinal safety of the novel injectable cyclooxygenase-2 selective inhibitor, parecoxib sodium, was compared with the nonselective nonsteroidal anti-inflammatory drug, ketorolac, and placebo in healthy subjects. STUDY: In a multicenter, randomized, double-blind, placebo-controlled design, 123 adults with endoscopically-confirmed normal upper gastrointestinal mucosae received parecoxib sodium 40 mg twice daily (7 days); placebo (2 days) followed by ketorolac 30 mg 4 times daily (5 days); or placebo (7 days) (each group n = 41). Posttreatment endoscopy scores were analyzed at 3 levels of severity: ulcers (scores of 7), > or =11 erosions/ulcers (scores of 5-7), and any erosions/ulcers (scores of 3-7). RESULTS: No subjects treated with parecoxib sodium or placebo developed gastroduodenal ulcers or > or =11 erosions/ulcers. Parecoxib sodium was comparable to placebo with respect to the combined incidence of erosions/ulcers (12% vs. 7%, P = 0.419). In contrast, in the ketorolac group, 11 (28%) subjects developed ulcers, 19 (48%) subjects developed > or =11 gastroduodenal erosions/ulcers, and the rate of combined ulcers/erosions was 85% (P < 0.001 vs. placebo and parecoxib sodium). CONCLUSIONS: Parecoxib sodium 40 mg twice daily for 7 days has a gastrointestinal safety profile superior to ketorolac 30 mg 4 times daily for 5 days, and comparable to placebo.

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.