Effect of oral siponimod (BAF312) on the pharmacokinetics and pharmacodynamics of a monophasic oral contraceptive in healthy female subjects

OBJECTIVE: To evaluate the effects of siponimod (BAF312) on the pharmacokinetics (PK) and pharmacodynamics (PD) of a monophasic oral contraceptive (OC). MATERIALS AND METHODS: This was a phase 1, single-center, open-label, multipledose, single-sequence study in healthy females. Eligible subjects (n = 23) were exposed sequentially to two treatment periods: period 1 (OC alone) and period 2 (OC + siponimod) in two consecutive menstrual periods. PK parameters were assessed on day 21 of both treatment periods. Follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, and progesterone concentrations were measured at baseline and days 3, 6, 8, 11, 14, 16, 19, 21, and 23 of each period. Largest ovarian follicle size and sex hormone-binding globulin (SHBG) concentration were measured and Hoogland score was calculated at baseline and day 21 of each period. Safety and tolerability of siponimod was also assessed. RESULTS: Co-administration (OC + siponimod) increased the AUC(τ,ss) and C(max,ss) of levonorgestrel by 28% and 18%, respectively, but had no effect on the PK of ethinylestradiol. No significant changes in estradiol, FSH, and LH were noted with co-administration vs. OC alone. Progesterone levels < 5 nmol/L, largest follicle size < 10 mm, and Hoogland score of 1 on day 21 indicated lack of ovulation in all subjects during co-administration. Co-administration was well tolerated. CONCLUSION: In conclusion, PK and PD of the OC were not altered to a clinically significant extent and contraceptive efficacy was maintained with co-administration. Hence, OC as a contraceptive measure can be safely co-administered with siponimod.