Journal of clinical pharmacology最新文献

Brivaracetam is an analogue of levetiracetam that is Food and Drug Administration-approved for adjunctive treatment of partial-onset seizures in patients 16 years and older. In placebo-controlled trials adjunct brivaracetam demonstrated efficacy in reducing the frequency of seizures. The most commonly reported adverse effects are somnolence, dizziness, and fatigue. Clinical trials have evaluated brivaracetam for safety and efficacy in adjunctive treatment of partial-onset seizures in patients 16 years and older for up to 16 weeks. Brivaracetam's mechanism is similar to that of levetiracetam but with greater receptor binding affinity on synaptic vesicle protein 2A and inhibitory effects on sodium channels. Clinically significant differences between these agents are undetermined. Brivaracetam is available as oral tablets, oral solution, and intravenous solution. The Food and Drug Administration-approved dose is 50 mg twice daily, and titration is not required. Brivaracetam does not need dose adjustment for renal impairment and has minimal drug-drug interactions. Current limitations of brivaracetam include lack of head-to-head trials, limited long-term safety and efficacy data, and cost. Overall, brivaracetam is a viable adjunct therapeutic option for refractory partial-onset seizures in those who have failed conventional therapies.

The correlation between simvastatin use and acute pancreatitis is explored. A case-control study was conducted to analyze claim data from the Taiwan National Health Insurance Program. The case group comprising a total of 3882 subjects aged 20 to 84 years with their first acute pancreatitis episode occurring between 1998 and 2011 formed the case group, against 3790 randomly selected controls matched for sex, age, comorbidities, and index year of acute pancreatitis diagnosis. Recent use of simvastatin was defined as subjects whose last remaining simvastatin tablet was noted ≤7 days before the date of acute pancreatitis diagnosis. Remote use of simvastatin was defined as subjects whose last remaining 1 tablet for simvastatin was noted >7 days before the date of acute pancreatitis diagnosis. Never use of simvastatin was defined as subjects who had never been prescribed simvastatin. A multivariable unconditional logistic regression model was used to estimate the odds ratio and 95%CI to explore the correlation between simvastatin use and acute pancreatitis. After adjustment for confounders, multivariable logistic regression analysis revealed that the adjusted odds ratio of acute pancreatitis was 1.3 for subjects with recent use of simvastatin (95%CI 1.02, 1.73), when compared with those with never use of simvastatin. The crude odds ratio decreased to 1.1 for those with remote use of simvastatin (95%CI 0.93, 1.34) but without statistical significance. Recent use of simvastatin is associated with acute pancreatitis. Clinicians should consider the possibility of simvastatin-associated acute pancreatitis for patients presenting for acute pancreatitis without known cause.

Venetoclax is a selective BCL-2 inhibitor that is approved in the United States for the treatment of patients with chronic lymphocytic leukemia (CLL) with 17p deletion who have received at least 1 prior therapy. The aim of this analysis was to characterize venetoclax pharmacokinetics in the plasma and urine of patients with hematological malignancies and evaluate the effect of dose proportionality, accumulation, weak and moderate CYP3A inhibitors, as well as low- and high-fat meals on venetoclax pharmacokinetics. Patients received a once-daily venetoclax dose of 20 to 1200 mg. Pharmacokinetic parameters were estimated using noncompartmental methods. Venetoclax peak exposures were achieved at 5 to 8 hours under low-fat conditions, and the mean terminal-phase elimination half-life ranged between 14.1 and 18.2 hours at different doses. Venetoclax steady-state exposures showed minimal accumulation and increased proportionally over the dose range of 300 to 900 mg. Low-fat and high-fat meals increased venetoclax exposures by approximately 4-fold relative to the fasting state. Moderate CYP3A inhibitors increased venetoclax exposures by 40% to 60%, whereas weak CYP3A inhibitors had no effect. A negligible amount of venetoclax was excreted in the urine. In summary, venetoclax exhibits a pharmacokinetic profile that is compatible with once-daily dosing with food regardless of fat content. Concomitant use of venetoclax with moderate CYP3A inhibitors should be avoided or venetoclax dose should be reduced during the venetoclax initiation and ramp-up phase in CLL patients. Renal excretion plays a minimal role in the elimination of venetoclax.

Tocilizumab is a humanized anti-interleukin-6 receptor antibody for treating rheumatoid arthritis. Pharmacokinetic/pharmacodynamic analysis was performed on the 24-week double-blind parts of 2 randomized, controlled trials: SUMMACTA and BREVACTA. SUMMACTA compared subcutaneous tocilizumab 162 mg every week to intravenous tocilizumab 8 mg/kg every 4 weeks, whereas BREVACTA evaluated 162 mg subcutaneous tocilizumab every 2 weeks versus placebo. In addition to noncompartmental analysis, a 2-compartment population pharmacokinetic model, with first-order absorption (for subcutaneous) and linear and Michaelis-Menten elimination was used. Mean observed steady-state predose tocilizumab concentrations in week 24 were 40 and 7.4 μg/mL for subcutaneous every-week and every-2-week dosing, respectively, and 18 μg/mL for intravenous dosing. In the population PK model, body weight was an important covariate affecting clearance and volume of distribution. Mean ± SD population-predicted predose concentration for patients ≥100 kg was 23.0 ± 13.5 μg/mL for subcutaneous tocilizumab every week and 1.0 ± 1.6 μg/mL for every 2 weeks. Efficacy was lowest with subcutaneous every-2-week dosing in patients > 100 kg, reflecting lower exposure. The subcutaneous every-2-week regimen is not recommended for these patients. Pharmacodynamic responses were comparable for the every-week subcutaneous and every-4-week intravenous regimens and less pronounced with the every-2-week subcutaneous regimen. No trend was observed for increased adverse events with increasing tocilizumab exposure. The results of this analysis are consistent with the noninferiority of efficacy of the every-week subcutaneous regimen to the every-4-week intravenous regimen and the superiority of the every-2-week subcutaneous regimen to placebo. These results support the label recommendations for subcutaneous dosing of tocilizumab in rheumatoid arthritis patients.

This study investigated postmarketing safety events (PMSEs) for new drugs approved in Brazil and evaluated whether a range of drug characteristics influenced the time between approval and the first PMSE. This retrospective study included new drugs registered between 2003 and 2013 by the National Health Surveillance Agency (ANVISA), which is responsible for medicines approval in Brazil. PMSEs were defined as any drug safety alert or drug withdrawal from the market. The existence of risk evaluation and mitigation strategies (REMS) by the US Food and Drug Administration (FDA) and Brazil were recorded. A Kaplan-Meier survival curve of the period between the date of ANVISA registration and the PMSE was calculated. We found a statistically significant difference between the time to PMSE for drugs with an FDA REMS compared with those without a REMS, with a log rank value (Mantel Cox) of 0.002. There was no association between the time to PMSE and the other drug characteristics investigated. This study demonstrated that the frequency of PMSEs for new drugs approved by ANVISA was statistically associated with the existence of an FDA REMS. The time between approval and first PMSE was shorter for drugs with an FDA REMS, and this finding may contribute to improved awareness of the risk/benefit balance required to ensure continued safe and effective use of new drugs.