Pharmacokinetic Characteristics of Siponimod in Healthy Volunteers and Patients With Multiple Sclerosis: Analyses of Published Clinical Trials

Objectives: This study aimed to investigate the pharmacokinetic characteristics of siponimod in healthy volunteers and patients with MS based on aggregated data from published clinical trials, and to explore the factors influencing siponimod exposure.

Methods: A total of 476 siponimod plasma concentrations aggregated from 28 dosage groups (corresponding to 294 healthy volunteers and 207 patients with MS) were collected from published clinical trials. Population pharmacokinetic (PPK) analysis was performed using a nonlinear, mixed-effect modeling approach. The pharmacokinetic properties of siponimod in healthy volunteers and patients with MS were compared, and the influence of covariates on siponimod exposure was evaluated using both PPK analysis and noncompartmental analysis (NCA).

Results: A one-compartment model with first-order absorption and elimination adequately described siponimod pharmacokinetics. The typical population parameter estimates of clearance (CL/F), apparent volume of distribution (V/F), and absorption rate constant (ka) were 3.17 L/h, 112.70 L, and 0.38 h⁻¹, respectively. An 11.85% lower siponimod clearance was estimated for patients with MS relative to healthy volunteers. Subgroup analyses using NCA assessments revealed that siponimod presented an accumulation index of approximately 2 after multiple administration. Compared with nonobese participants, obese participants had a relatively lower dose-corrected area under the concentration-time curve (AUC_0-∞/D) (0.31 vs. 0.42 h/L) and V/F (120.95 vs. 133.75 L), and a relatively higher CL/F (3.25 vs. 3.21 L/h). Participants with CYP2C9*2/*3, *1/*3, and *3/*3 genotypes experienced an increased (1.3- and 3.4-fold, respectively) AUC_0-∞/D and a decreased (0.7- and 0.3-fold, respectively) CL/F compared with those in participants with the CYP2C9*1/*1, *1*2, and *2*2 genotypes. Fluconazole combination led to a decrease in CL/F (approximately 0.5 times) and an increase in AUC_0-∞/D (approximately 1.3 times).

Conclusion: Siponimod pharmacokinetic properties in healthy volunteers and patients with MS were explored using complementary model-based meta-analysis (MBMA) and NCA approaches. A slightly lower siponimod clearance was observed in patients with MS than in healthy volunteers. The dosage regimen, body mass index, CYP2C9 genetic polymorphism and fluconazole combination may had influences on siponimod pharmacokinetics. Such model paves the road to more population-based analyses in different patient populations with MS to quantify the effect of any influencing factors on siponimod pharmacokinetics.

Absence of ethnic differences in the pharmacokinetics of moxifloxacin, simvastatin, and meloxicam among three East Asian populations and Caucasians

Aim

To examine whether strict control of clinical trial conditions could reduce apparent differences of pharmacokinetic (PK) parameters among ethnic groups.

Methods

Open‐label, single dose PK studies of moxifloxacin, simvastatin and meloxicam were conducted in healthy male subjects from three East Asian populations (Japanese, Chinese and Koreans) and one Caucasian population as a control. These three drugs were selected because differences in PK parameters have been reported, even though the backgrounds of these East Asian populations are similar. Moxifloxacin (400 mg) was administered orally to 20 subjects, and plasma and urine levels of moxifloxacin and its metabolite (M2) were measured. Simvastatin (20 mg) was given to 40 subjects, and plasma levels of simvastatin and simvastatin acid were measured. Meloxicam (7.5 mg) was given to 30 subjects and its plasma concentration was determined. Intrinsic factors (polymorphism of UGT1A1 for moxifloxacin, SLCO1B1 for simvastatin, and CYP2C9 for meloxicam) were also examined.

Results

AUC_inf values for moxifloxacin, simvastatin and meloxicam showed no significant differences among the East Asian groups. C_max values of moxifloxacin and simvastatin, but not meloxicam, showed significant differences. There were no significant differences of data for M2 or simvastatin acid. Genetic analysis identified significant differences in the frequencies of relevant polymorphisms, but these differences did not affect the PK parameters observed.

Conclusions

Although there were some differences in PK parameters among the three East Asian groups, the present study performed under strictly controlled conditions did not reproduce the major ethnic differences observed in previous studies.

Mifepristone-induced abortion and birth weight in the first subsequent pregnancy

OBJECTIVES

To assess the effect of a medically induced abortion (MA) on birth weight in the first subsequent pregnancy.

METHODS

Pregnant women who had had a MA, a surgical abortion (SA), or primigravidas with no history of abortion (NA), were recruited for a prospective cohort study between July 1998 and February 2001. The sample for the present analysis included 12995 singleton live births at term.

RESULTS

The overall incidence rate of low birth weight (LBW) was 1.0%. The rates of LBW in the MA, SA, and NA groups were 1.0%, 0.9%, and 1.2, respectively. There were no significant differences in LBW rates between the MA and SA groups, neither between the MA and NA. Logistic regression analysis was used to estimate the effects of MA on birth weight, and we found no relationship between risk of LBW and MA.

CONCLUSIONS

We did not find a statistically significant relationship between a history of one medically induced abortion and LBW for the first subsequent term pregnancy.

Use of the female condom among sex workers in China

OBJECTIVES

To introduce the female condom (FC) among sex workers (SWs) in China.

METHODS

We adopted the intervention study method. The 315 participating SWs were randomly assigned to an intervention group (155 SWs) or a control group (160 SWs).

RESULTS

The rate of SWs who reported liking FC increased from 60.0% pre-intervention to 93.5% post-intervention, and the rate of SWs who considered that their clients could accept FC increased from 27.1% to 92.3%. After the intervention, 93.5% expressed that their sexual satisfaction had increased with their familiarity with FC and 97.4% expressed that they would use it in the future.

CONCLUSIONS

The understanding and use of FC can be greatly improved through active intervention-i.e. medical workers providing SWs with FC.

Case-controlled study on relevant factors of adolescent sexual coercion in China

This was a case-controlled study to determine factors related to sexual coercion among adolescent abortion seekers in China. We considered the abortion-seeking women who had experienced sexual coercion as the case group and the abortion-seeking women who had never experienced sexual coercion as the control group. The results of the study indicated that the factors more likely to be related to sexual coercion include lower educational level [odds ratio (OR) = 1.55], not living with parents (OR) = 1.57, floating population (OR = 1.63), beaten by her partner (OR = 2.87), abused by her partner (OR = 1.84), multiple partners (OR = 2.10), sex after excessive drinking (OR = 5.02), younger age at first intercourse (OR = 1.68), and large difference in age between men and women (OR = 2.02). The relevant factors most likely to be associated with sexual coercion are poorly educated, not living with parents, floating population, multiple partners, younger age at first sex, and inequality between men and women.