Pharmacodynamic assessment of prasugrel and clopidogrel in patients with non-cardioembolic stroke: a multicenter, randomized, active-control clinical trial.

Prasugrel, a novel P2Y12 receptor antagonist, has been shown to be more effective than clopidogrel for preventing cardiovascular events in patients with acute coronary syndromes undergoing percutaneous coronary intervention. We investigated the dose-response antiplatelet effects of prasugrel compared with clopidogrel in Japanese patients with non-cardioembolic stroke. The influence of cytochrome P450 (CYP) polymorphisms on the antiplatelet effects of both drugs was also compared. In this multicenter randomized active-control comparative study, patients were randomized to receive prasugrel 2.5 mg, 5 mg, or 7.5 mg (double blind) or clopidogrel 75 mg (open label) once daily for 14 days. The primary endpoint was inhibition of platelet aggregation (IPA) in response to adenosine diphosphate 20 µM within 8 h of study drug administration on day 14. Of the 66 patients randomized, data from 63 (prasugrel 2.5 mg, 5 mg, and 7.5 mg groups, n = 14, 16, and 18, respectively; clopidogrel group, n = 15) were used in the pharmacodynamic assessment. IPA (arithmetic mean ± SD) after prasugrel administration increased dose-dependently (33 ± 9%, 44 ± 11%, and 53 ± 14%, at 2.5 mg, 5 mg, and 7.5 mg, respectively) and was higher in these groups than after clopidogrel (23 ± 16%). In a subgroup of CYP2C19 intermediate metabolizers, IPA was higher in the prasugrel 5 mg and 7.5 mg groups than in the clopidogrel group. No death or serious adverse events were reported. Prasugrel was well tolerated at doses up to 7.5 mg/day and had antiplatelet effects higher than those of clopidogrel 75 mg/day. CYP2C19 polymorphisms may have reduced clopidogrel-induced IPA.

Influence of cytochrome P450 polymorphisms on the antiplatelet effects of prasugrel in patients with non-cardioembolic stroke previously treated with clopidogrel.

This randomized double-blind crossover study aimed to investigate the influence of cytochrome P450 (CYP) 2C19 polymorphisms on the antiplatelet effects of prasugrel in patients with non-cardioembolic stroke treated with clopidogrel. Patients received clopidogrel 75 mg/day for > 4 weeks. Subsequently, patients received prasugrel 3.75 mg/day (group A; n = 64) or 2.5 mg/day (group B; n = 65) for 4 weeks followed by a 4 week switched-dose regimen. To assess the influence of CYP2C19 polymorphisms, patients were classified as extensive metabolizers (EMs), intermediate metabolizers (IMs), and poor metabolizers (PMs). The primary endpoint was P2Y12 reaction units (PRU) at the end of each 4 week treatment. A significant reduction in PRU was noted after treatment with prasugrel 3.75 mg/day compared with the pre-dose value (after treatment with clopidogrel) (p < 0.0001). By CYP2C19 phenotypes, a significant reduction in PRU was noted in IMs and PMs after treatment with prasugrel 3.75 mg/day and in PMs after treatment with prasugrel 2.5 mg/day, as compared with the pre-dose value (p < 0.0001). The plasma concentration of the active metabolite of clopidogrel was relatively low in PMs compared to EMs and IMs; prasugrel was similar across all CYP2C19 phenotypes. No major or clinically significant hemorrhagic adverse events occurred. By CYP2C19 phenotype, the antiplatelet effects of prasugrel were greater with 3.75 mg/day in IMs and PMs, and with 2.5 mg/day in PMs compared with clopidogrel 75 mg/day, without safety concerns. CYP2C19 polymorphisms did not affect the plasma concentration of the active metabolite of prasugrel or its antiplatelet effects. (JapicCTI-101044).

Pharmacokinetics and Bioequivalence of Mirogabalin Orally Disintegrating Tablets and Conventional Tablets in Healthy Japanese Participants.

This single-center, randomized, open-label, single-dose, 2-group, 2-stage crossover trial evaluated the bioequivalence of 15 mg of mirogabalin as orally disintegrating tablets (ODTs) with conventional mirogabalin tablets in healthy Japanese men. The trial involved two studies: in Study 1, the ODT formulation was taken without water, and in Study 2, the ODT formulation was taken with water. The conventional tablet was taken with water in both studies. We investigated the pharmacokinetic parameters and bioequivalence of the 2 formulations, including the maximum plasma concentration and the area under the plasma concentration-time curve up to the last quantifiable time. The plasma concentrations of mirogabalin were determined by a validated liquid chromatography with tandem mass spectrometry method. A total of 72 participants were enrolled and completed the trial. The geometric least-squares mean ratios of maximum plasma concentration of the ODT formulation to the conventional formulation were within the prespecified bioequivalence range of 0.80-1.25 (Study 1, 0.995; Study 2, 1.009), as was the area under the plasma concentration-time curve up to the last quantifiable time (Study 1, 1.023; Study 2, 1.035). No serious adverse events were observed. In conclusion, mirogabalin 15-mg ODTs, either with or without water, were bioequivalent to conventional 15-mg tablets.

Intrapulmonary distribution and pharmacokinetics of laninamivir, a neuraminidase inhibitor, after a single inhaled administration of its prodrug, laninamivir octanoate, in healthy volunteers.

A single inhaled dose of laninamivir octanoate (LO), a long-acting neuraminidase inhibitor, exhibits efficacy in treating both adult and pediatric patients with influenza virus infection. The intrapulmonary pharmacokinetics (PK) of LO and laninamivir, a pharmacologically active metabolite, were investigated by a single-center, open-label study of healthy adult volunteers. Subgroups of five subjects each underwent bronchoalveolar lavage (BAL) 4, 8, 24, 48, 72, 168, and 240 h following a single inhaled administration of LO (40 mg). Plasma, BAL fluid, and alveolar macrophages (AM) were analyzed to determine LO and laninamivir concentrations, using validated liquid chromatography-tandem mass spectrometry methods. The concentrations in epithelial lining fluid (ELF) and AM from the first and subsequent BAL fluid samples were determined separately to explore the drug distribution in airways. Mean laninamivir concentrations in ELF, calculated using the first BAL fluids and BAL fluids collected 4 h after inhaled administration, were 8.57 and 2.40 µg/ml, respectively. The laninamivir concentration in ELF decreased with a longer half-life than that in plasma, and it exceeded the 50% inhibitory concentrations for viral neuraminidases at all time points examined for 240 h after the inhalation. Laninamivir exposure in ELF from the first BAL samples was 3.2 times higher than that in ELF from the subsequent BAL fluid samples. ELF concentration profiles of laninamivir support its long-lasting effect for treatment of patients with influenza virus infection by a single inhaled administration.

[Pharmacological, pharmacodynamics, and clinical profile of mirogabalin besylate (Tarlige® tablets 2.5†mg∙5†mg∙10†mg∙15†mg)].

Mirogabalin, a novel ligand for the α2δ subunit of voltage-gated calcium channels, has been approved for the treatment of peripheral neuropathic pain including painful diabetic peripheral neuropathy (DPNP) and postherpetic neuralgia (PHN) in Japan. Mirogabalin showed potent and selective binding affinities for the α2δ subunits, and slower dissociation rates for the α2δ-1 subunit than for the α2δ-2 subunit. It also showed potent and long-lasting analgesic effects in rat models of neuropathic pain, and wider safety margins for the central nervous system side effects. A pharmacological study using mutant mice demonstrated that the analgesic effects of mirogabalin were mediated by binding of the drug to the α2δ-1 subunit, not the α2δ-2 subunit. The pharmacological properties of mirogabalin can be associated with its unique binding characteristics. The bioavailability of mirogabalin is high and its plasma exposure increases dose-proportionally. Mirogabalin is mainly excreted via the kidneys in an unchanged form, thus, mirogabalin has a low possibility of undergoing drug-drug interaction, while dose adjustment based on the creatinine clearance level is specified in patients with renal impairment. In double-blind, placebo-controlled phase 3 studies in Asian patients with DPNP and PHN, mirogabalin showed significant and dose-dependent pain relief, and all tested doses of mirogabalin were well tolerated. In summary, mirogabalin has a balanced efficacy versus safety profile, and can provide an alternative therapeutic option for the treatment of peripheral neuropathic pain.

Population pharmacokinetic analysis of patritumab, a HER3 inhibitor, in subjects with advanced non-small cell lung cancer (NSCLC) or solid tumors.

PURPOSE: The purpose of this analysis was to develop a population pharmacokinetic (PK) model for patritumab, a fully human monoclonal antibody that targets human epidermal growth factor receptor 3. METHODS: A total of 833 serum concentrations were included in this analysis; serum concentrations were obtained from 145 subjects (136 with non-small cell lung cancer, nine with solid tumors) treated with patritumab [9 or 18 mg/kg intravenously every 3 weeks (q3w)] in one phase 1 and one phase 1b/2 study. Data were analyzed by nonlinear mixed-effect modeling. RESULTS: Patritumab PKs were best described through a two-compartment model with first-order elimination and interindividual variability on clearance (CL), volume of the central compartment (V c), distributional clearance, and volume of the peripheral compartment. In the final model, CL and V c were estimated as 0.0238 L/h and 3.62 L, respectively. Body weight (BW) and baseline albumin were found to be covariates for CL and BW was a covariate for V c. Covariates associated with hepatic and renal impairment were not significant on CL. Simulations showed that BW-based dosing reduced interindividual variability in patritumab exposure compared with fixed dosing. CONCLUSIONS: The PK of patritumab was linear at the doses studied and well described by the two-compartment model. Hepatic and renal impairment did not appear to affect PK. Our results support BW-based dosing of patritumab on a q3w schedule.

Assessment of the effects of renal impairment on the pharmacokinetic profile of laninamivir, a novel neuraminidase inhibitor, after a single inhaled dose of its Prodrug, CS-8958.

This open-label, single-dose study assessed the safety and pharmacokinetics of laninamivir, a new long-acting neuraminidase inhibitor, after an inhaled 20-mg dose of its prodrug, CS-8958, to a total of 20 subjects with normal, mild, moderate, or severe renal impairment. CS-8958 and laninamivir concentrations were measured in plasma and urine by validated liquid chromatography tandem mass spectrometry methods. The area under the concentration-time curve extrapolated to infinity (AUC(0-inf)), maximum concentration (C(max)), and time to C(max) of CS-8958 did not change with the degree of renal impairment, whereas the half-life (t(1/2)) of CS-8958 increased with increasing renal insufficiency. The AUC(0-inf) and C(max) of laninamivir tended to increase along with the decrease of creatinine clearance. The AUC(0-inf) of laninamivir compared with normal subjects increased 1.10-, 2.03-, and 4.92-fold in subjects with mild, moderate, and severe renal impairment, respectively, without changing t(1/2) among the subjects. Renal clearance of both CS-8958 and laninamivir was well correlated with creatinine clearance. These data indicate that the rate-limiting step for the elimination of laninamivir would not be the renal excretion rate but rather the drug release rate to plasma from the retained tissues. CS-8958 was well tolerated by all the subjects, although increasing renal dysfunction leads to increasing systemic exposure to laninamivir, particularly in severe renal insufficiency.

Clinical pharmacokinetics of laninamivir, a novel long-acting neuraminidase inhibitor, after single and multiple inhaled doses of its prodrug, CS-8958, in healthy male volunteers.

Phase 1 studies of laninamivir, a novel long-acting neuraminidase inhibitor, were carried out to assess its safety, tolerability, and pharmacokinetics after inhaled administration of its prodrug, CS-8958. Healthy male volunteers (total N = 76) participated in double-blind, randomized, placebo-controlled trials and received 5, 10, 20, 40, 80, or 120 mg of a single dose or 20 or 40 mg of a twice-daily dose for 3 days. The clinical and laboratory parameters and plasma and urinary concentrations of CS-8958 and laninamivir for 144 hours post dosing were measured. There were no adverse events related to the test drug. CS-8958 disappeared from plasma with a half-life of about 2 hours, although laninamivir was slowly eliminated from the body, lasting for even up to 144 hours after administration with a half-life of about 3 days. Area under the curve and maximum concentration increased almost linearly with the dose administered. The cumulative urinary excretion amounts of CS-8958 and laninamivir were 2.3% to 3.6% and 10.7% to 14.6% of the dose, respectively. The half-life of the urinary excretion rates of laninamivir at higher single dose is comparable to plasma half-life. CS-8958, when inhaled by healthy volunteers, is well tolerated and exhibits a suitable pharmacokinetic profile, suggesting potential for long-lasting anti-influenza activity.