Clinical Pharmacology : Advances and Applications最新文献

As a result of an increasing aging population, the number of individuals taking multiple medications simultaneously has grown considerably. For these individuals, taking multiple medications has increased the risk of undesirable drug-drug interactions (DDIs), which can cause serious and debilitating adverse drug reactions (ADRs). A comprehensive understanding of DDIs is needed to combat these deleterious outcomes. This review provides a synopsis of the pharmacokinetic (PK) and pharmacodynamic (PD) mechanisms that underlie DDIs. PK-mediated DDIs affect all aspects of drug disposition: absorption, distribution, metabolism and excretion (ADME). In this review, the cells that play a major role in ADME and have been investigated for DDIs are discussed. Key examples of drug metabolizing enzymes and drug transporters that are involved in DDIs and found in these cells are described. The effect of inhibiting or inducing these proteins through DDIs on the PK parameters is also reviewed. Despite most DDI studies being focused on the PK effects, DDIs through PD can also lead to significant and harmful effects. Therefore, this review outlines specific examples and describes the additive, synergistic and antagonistic mechanisms of PD-mediated DDIs. The effects DDIs on the maximum PD response (E _max) and the drug dose or concentration (EDEC₅₀) that lead to 50% of E _max are also examined. Significant gaps in our understanding of DDIs remain, so innovative and emerging approaches are critical for overcoming them.

Purpose: Human sarcomas are rare and difficult to treat cancerous tumors typically arising from soft tissue or bone. Conversely, carcinomas are the most common cancer subtype in humans and the primary cause of mortality across all cancer patients. While conventional therapeutic modalities can prolong disease-free intervals and survival in some cases, treatment of refractory or recurrent solid tumors is challenging, and tumor-related mortality remains unacceptably high. The identification of overexpressed cell surface receptors on sarcoma and carcinoma cells has provided a valuable tool to develop targeted toxins as an alternative anticancer strategy. Recent investigation of recombinant protein-linked toxins that specifically target these cancer receptors has led to the development of highly specific, cytotoxic, and deimmunized drugs that can kill cancer cells.

Methods: This study investigated a recombinant protein called epidermal growth factor bispecific angiotoxin (eBAT), which is designed to target the epidermal growth factor receptor (EGFR) on cancer cells and the urokinase plasminogen activator receptor (uPAR) on cancer cells and associated tumor vasculature. Both receptors are expressed by a variety of human sarcomas and carcinomas. Flow cytometry techniques were used to determine binding affinity of eBAT to cancer cells, and proliferation assays were performed to calculate tumor killing ability based on half-maximal inhibitory concentrations.

Results: eBAT demonstrated cytotoxicity against a variety of sarcoma and carcinoma cells that overexpress EGFR and uPAR in vitro and showed greater cell killing ability and binding affinity to cancer cells compared with its monospecific counterparts.

Conclusion: The results of our study are promising, and further studies will be necessary to confirm the applicability of eBAT as a supplementary therapy for a variety of sarcomas, carcinomas, and possibly other refractory malignancies that express EGFR and uPAR.

Purpose: Cinacalcet is a positive allosteric modulator of calcium-sensing receptors in the parathyroid gland and an effective treatment for secondary hyperparathyroidism. However, this agent has considerable side effects and dosage limitations, which impair effective treatment. Therefore, we investigated the pharmacokinetics, pharmacodynamics, and safety of the novel calcimimetic, evocalcet.

Patients and methods: This was a multicenter, open-label study of single oral doses of 1, 4, and 12 mg evocalcet using an intrapatient dose escalation protocol in 29 Japanese secondary hyperparathyroidism patients receiving hemodialysis. Pharmacokinetics was assessed by plasma evocalcet concentrations. Pharmacodynamic evaluations consisted of measuring intact parathyroid hormone, serum corrected calcium, and fibroblast growth factor 23 concentrations. Safety and tolerability were evaluated by the analysis of adverse events (AEs).

Results: After a single 1-, 4-, or 12-mg dose, plasma evocalcet levels increased dose proportionally in a linear manner. Pharmacodynamic analyses showed that evocalcet effectively reduced intact parathyroid hormone and serum corrected calcium levels in a dose-dependent manner. AEs occurred in 31.0%, 28.6%, and 38.5% of patients receiving a single dose of 1, 4, or 12 mg, respectively. Most AEs were mild in severity.

Conclusion: Evocalcet is effective in the short term, has linear pharmacokinetics, and is well tolerated as observed by the low incidence of AEs.

Objective: The aim of this study was to evaluate the bioavailability of a pomalidomide oral liquid suspension relative to the commercial capsule formulation and to assess the food effect on the pomalidomide oral liquid suspension when administered as a single 4 mg dose.

Methods: This was an open-label, randomized, three-period, two-sequence crossover study in healthy subjects consisting of a screening phase, a baseline assessment phase, a treatment phase with three periods, and a follow-up phone call phase. Blood samples for pharmacokinetics (PK) assessment were collected up to 48 h postdose during each treatment period. Safety was evaluated throughout the study.

Results: Pomalidomide exposures were comparable in healthy subjects administered with a single oral 4 mg dose as the reference capsule or as the test liquid suspension formulations, demonstrated as the 90% confidence intervals of the geometric mean ratios for area under the plasma concentration-time curve calculated from time 0 to the last measurable concentration at time t (AUC_0-t), area under the plasma concentration-time curve from time 0 to infinity (AUC_0-∞), and peak (maximum) plasma drug concentration (C_max) were completely contained within the bioequivalence range of 80-125%. Administration of the pomalidomide liquid suspension with a high fat meal resulted in a 3.0 h delay in pomalidomide time to C_max (t_max) and an ~ 34.5% reduction in C_max. However, the AUCs were comparable after dose administration with and without food.

Conclusion: A single oral dose of 4 mg of liquid suspension was bioequivalent to a single oral dose of 4 mg of capsule formulation. There was no clinically relevant impact of food on pomalidomide liquid suspension. Single oral doses of 4 mg pomalidomide were safe and well tolerated when administered as a liquid suspension under fed and fasted conditions or as a capsule under fasted conditions.

Background: Rabies immune globulin (RIG) and vaccination series are necessary for postexposure prophylaxis. A new formulation of RIG (human) purified by caprylate/chromatography (RIG-C) was evaluated.

Trial registration: ClinicalTrials.gov identifier: NCT02139657.

Materials and methods: This open-label, single-arm study in healthy subjects evaluated neutralizing rabies antibody concentrations produced from a single 20 IU/kg intramuscular (IM) dose of RIG-C as measured by rapid fluorescent focus inhibition test (50% neutralization endpoint) 1-hour postdose and on days 1, 2, 4, 6, 8, 10, 14, 18, and 21.

Results: Twelve subjects were enrolled into the study. No discontinuations, serious adverse events (AEs), or treatment-emergent clinically significant changes in laboratory parameters were observed. All AEs resolved and were mild except 1 moderate AE of oropharyngeal pain. Injection site pain (4 subjects) was most commonly reported. RIG-C produced a rapid increase in neutralizing rabies antibody: mean value 0.113 IU/mL at 24 hours after IM injection, peak on day 4 (0.132 IU/mL), persisting through day 21 (0.116 IU/mL). The mean reciprocal titer was 11.5 by day 2; the peak value of 12.1 was achieved on day 4; and a mean value ≥10.6 was maintained through day 21.

Conclusion: RIG-C was well tolerated and provided neutralizing rabies antibodies, which combined with vaccine series after rabies exposure, should result in effective prophylaxis per World Health Organization/Centers for Disease Control and Prevention guidelines.

Introduction: This study explored D-ribose pharmacokinetics after intravenous (IV) and oral administration to healthy rabbits.

Materials and methods: D-ribose was administered once as 420 mg/kg (N=4) or 840 mg/kg (N=6) dose intravenously, or as an oral dose of 420 mg/kg (N=3) or 840 mg/kg (N=3). Serum was obtained at various time points, up to 210 minutes after administration. Urine was also collected after IV administration. Pharmacokinetic parameters were determined from drug concentration-time data using Kinetica software.

Results: The findings showed that D-ribose follows a dose-dependent kinetic profile. With doubling the IV dose, AUC_total was significantly increased by threefold, while the clearance was decreased by 44%. The half-life was 1.7-fold longer at the higher dose. Similar nonsignificant trends were also observed at oral administration. D-ribose was rapidly absorbed (T_max=36-44 minutes) and rapidly disappeared from plasma (within <140 minutes). Additionally, D-ribose was partially (18-37.5%) recovered from urine.

Conclusion: Collectively, D-ribose showed a dose-dependent kinetic profile, where parameters change according to dosing levels. D-ribose clearance seems to follow first-order kinetics at low dose. Thereafter, elimination systems are saturated, and elimination continues in a fast manner. Urine recovery was partial, which could be attributed to the several metabolic pathways that pentose can undergo.

[This corrects the article on p. 179 in vol. 6, PMID: 25419161.].

Objectives: To evaluate the degree of anticoagulation achieved with different enoxaparin dosing regimens used in obese and morbidly obese patients in a hospital setting in Jordan.

Methods: All obese adult patients who were prescribed enoxaparin for various indications were invited to participate in the study. The anti-factor Xa (anti-Xa) level was checked once after 4-6 hours of the third or fourth dose of enoxaparin (at steady state). Patients were followed daily to evaluate drug efficacy and safety through their hospital course.

Results: Enoxaparin daily dose used for prophylaxis indications ranged from 0.3 to 0.85 mg/kg and from 0.31 to 2.25 mg/kg in case of certain treatment indications. Most participants who received enoxaparin for treatment indications (76.9%) were on capping dosing regimens, which was <1 mg/kg twice daily. On the other hand, most patients (88.5%) who received enoxaparin for prophylaxis indications were on a fixed 40 mg/d dose. Among the 52 patients who completed the study, 19 patients (36.5%) had therapeutic anti-Xa levels. The results showed no statistically significant associations between regimens that were used and achieving therapeutic anti-Xa level (p>0.05). No bleeding events or thrombocytopenia were noticed, and there was one case of recurrent thrombosis.

Conclusion: Enoxaparin dosing regimens that were used for obese patients varied based on prescribing physicians. Regardless of the regimen used, the majority of participants had nontherapeutic anti-Xa. Individualized dosing regimens based on anti-Xa levels are warranted for obese patients on enoxaparin.

Objective: To assess whether pomalidomide can distribute into human semen and its duration in human semen.

Method: A phase 1, randomized, double-blind, placebo-controlled study (CC-4047-CP-006) was conducted to evaluate the safety, tolerability, and pharmacokinetics of pomalidomide (CC-4047) following multiple daily doses in healthy male subjects. Semen samples were collected on Day -1 and 4 hours after dosing on Day 4 to quantify the pomalidomide concentrations in ejaculate after multiple oral doses of pomalidomide.

Result: Our study showed that pomalidomide was present in male subjects' semen samples, and the average amount of pomalidomide in a single ejaculate 4 hours after dosing was less than 0.0022% of the daily 2 mg dose. There was a good correlation between the semen concentrations and the plasma concentrations, suggesting that the plasma concentration may be the main driving force for the distribution of pomalidomide into the seminal reservoirs. Simulation results suggest that pomalidomide was undetectable in semen 48 hours after stopping dosing.

Conclusion: Based on the results from this study, the pomalidomide prescribing information approved by the US Food and Drug Administration includes a statement that "pomalidomide is present in the semen of patients receiving the drug. Therefore, males must always use a latex or synthetic condom during any sexual contact with females of reproductive potential while taking POMALYST and for up to 4 weeks after discontinuing POMALYST, even if they have undergone a successful vasectomy. Male patients taking POMALYST must not donate sperm."

Purpose: The current study aimed to evaluate whether a generic product of etoricoxib 120 mg film-coated tablet (the test drug) was bioequivalent to the reference product (Arcoxia® film-coated tablet 120 mg).

Methods: This was a randomized, open-label, two-sequence, crossover study under fasting condition, with a 14-day washout period, involving 26 healthy adult male and female subjects. Blood samples were taken and analyzed for plasma concentrations of etoricoxib (Chemical Abstracts Service [CAS] 202409-33-4) using a high-pressure liquid chromatography-ultraviolet detector (HPLC-UV) system capable of measuring etoricoxib concentrations ranging from 5.00 to 5002.90 ng/mL, with the lowest limit of quantitation of 5.00 ng/mL. A noncompartmental method was used to determine the pharmacokinetic parameters of a single-dose administration of the drug, including the area under plasma concentration-time curve from time zero to the time of last observed concentration (AUC_0-t ), the area under plasma concentration-time curve from time zero to infinity (AUC_0-∞), the maximum plasma concentration (C_max), the time to reach the maximum plasma concentration (t_max), and the terminal half-life (t_½).

Results: After a single-dose administration of etoricoxib 120 mg film-coated tablet, the mean (SD) values for the AUC_0-72h and C_max of the test drug were 45913.42 (13142.19) ng·h/mL and 3155.93 (752.81) ng/mL, respectively; the values for the reference drug were 44577.20 (13541.85) ng·h/mL and 2915.13 (772.81) ng/mL, respectively. The geometric mean ratios (90% CIs) of the test drug/reference drug were 103.40% (98.70%-108.32%) for AUC_0-72h and 109.26% (100.18%-119.18%) for C_max. No clinically significant differences in t_max and t_½values were found between the test drug and the reference drug. No adverse events were experienced by the subjects during this study.

Conclusion: The present study demonstrated that the evaluated generic etoricoxib 120 mg film-coated tablets were bioequivalent to the reference drug.