Pharmacokinetic studies with a vaginal delivery system releasing levonorgestrel at a near zero order rate for one year

Randomized, placebo controlled phase I trial of the safety, pharmacokinetics, pharmacodynamics and acceptability of a 90 day tenofovir plus levonorgestrel vaginal ring used continuously or cyclically in women: The CONRAD 138 study

Multipurpose prevention technologies (MPTs), which prevent sexually transmitted infection(s) and unintended pregnancy, are highly desirable to women. In this randomized, placebo-controlled, phase I study, women used a placebo or tenofovir (TFV) and levonorgestrel (LNG) intravaginal ring (IVR), either continuously or cyclically (three, 28-day cycles with a 3 day interruption in between each cycle), for 90 days. Sixty-eight women were screened; 47 were randomized to 4 arms: TFV/LNG or placebo IVRs used continuously or cyclically (4:4:1:1). Safety was assessed by adverse events and changes from baseline in mucosal histology and immune mediators. TFV concentrations were evaluated in multiple compartments. LNG concentration was determined in serum. Modeled TFV pharmacodynamic antiviral activity was evaluated in vaginal and rectal fluids and cervicovaginal tissue ex vivo. LNG pharmacodynamics was assessed with cervical mucus quality and anovulation. All IVRs were safe with no serious adverse events nor significant changes in genital tract histology, immune cell density or secreted soluble proteins from baseline. Median vaginal fluid TFV concentrations were >500 ng/mg throughout 90d. TFV-diphosphate tissue concentrations exceeded 1,000 fmol/mg within 72hrs of IVR insertion. Mean serum LNG concentrations exceeded 200 pg/mL within 2h of TFV/LNG use, decreasing quickly after IVR removal. Vaginal fluid of women using TFV-containing IVRs had significantly greater inhibitory activity (87-98% versus 10% at baseline; p<0.01) against HIV replication in vitro. There was a >10-fold reduction in HIV p24 antigen production from ectocervical tissues after TFV/LNG exposure. TFV/LNG IVR users had significantly higher rates of anovulation, lower Insler scores and poorer/abnormal cervical mucus sperm penetration. Most TFV/LNG IVR users reported no change in menstrual cycles or fewer days of and/or lighter bleeding. All IVRs were safe. Active rings delivered high TFV concentrations locally. LNG caused changes in cervical mucus, sperm penetration, and ovulation compatible with contraceptive efficacy. Trial registration: ClinicalTrials.gov #NCT03279120.

Randomized, placebo controlled phase I trial of safety, pharmacokinetics, pharmacodynamics and acceptability of tenofovir and tenofovir plus levonorgestrel vaginal rings in women

To prevent the global health burdens of human immunodeficiency virus [HIV] and unintended/mistimed pregnancies, we developed an intravaginal ring [IVR] that delivers tenofovir [TFV] at ~10mg/day alone or with levonorgestrel [LNG] at ~20μg/day for 90 days. We present safety, pharmacokinetics, pharmacodynamics, acceptability and drug release data in healthy women. CONRAD A13-128 was a randomized, placebo controlled phase I study. We screened 86 women; 51 were randomized to TFV, TFV/LNG or placebo IVR [2:2:1] and 50 completed all visits, using the IVR for approximately 15 days. We assessed safety by adverse events, colposcopy, vaginal microbiota, epithelial integrity, mucosal histology and immune cell numbers and phenotype, cervicovaginal [CV] cytokines and antimicrobial proteins and changes in systemic laboratory measurements, and LNG and TFV pharmacokinetics in multiple compartments. TFV pharmacodynamic activity was measured by evaluating CV fluid [CVF] and tissue for antiviral activity using in vitro models. LNG pharmacodynamic assessments were timed based on peak urinary luteinizing hormone levels. All IVRs were safe with no significant colposcopic, mucosal, immune and microbiota changes and were acceptable. Among TFV containing IVR users, median and mean CV aspirate TFV concentrations remained above 100,000 ng/mL 4 hours post IVR insertion and mean TFV-diphosphate [DP] concentrations in vaginal tissue remained above 1,000 fmol/mg even 3 days post IVR removal. CVF of women using TFV-containing IVRs completely inhibited [94-100%] HIV infection in vitro. TFV/LNG IVR users had mean serum LNG concentrations exceeding 300 pg/mL within 1 hour, remaining high throughout IVR use. All LNG IVR users had a cervical mucus Insler score <10 and the majority [95%] were anovulatory or had abnormal cervical mucus sperm penetration. Estimated in vivo TFV and LNG release rates were within expected ranges. All IVRs were safe with the active ones delivering sustained high concentrations of TFV locally. LNG caused changes in cervical mucus, sperm penetration, and ovulation compatible with contraceptive efficacy. The TFV and TFV/LNG rings are ready for expanded 90 day clinical testing. Trial registration ClinicalTrials.gov #NCT02235662.

Studies on a vaginal ring releasing levonorgestrel at an initial rate of 27 micrograms/24 h when used alone or in combination with transdermal systems releasing estradiol

Vaginal rings releasing levonorgestrel (L-NOG) at an initial rate of 27 micrograms/24h were studied in a group of 24 normally menstruating women during three months (i.e., during three four-week segments). Each segment consisted of three weeks with the vaginal rings in situ followed by a treatment-free period of one week. The women were divided into three groups (8 subjects each). The first group received vaginal rings only, the second and third groups were treated, in addition, with transdermal systems (patches) releasing estradiol at a rate of 50 and 100 micrograms/24h, respectively. Peripheral blood samples were withdrawn three times weekly (Monday, Wednesday and Friday) during a pretreatment cycle and during the following three months of treatment. The levels of L-NOG, estradiol and progesterone were analyzed by radioimmunoassay techniques. In all subjects, endometrial biopsies were taken in a control cycle and during the last days with vaginal rings in situ in segments II and III. The treatment with estradiol did not significantly influence L-NOG levels. Considerable differences in the L-NOG levels between the subjects of the same group were observed. Fluctuation in ovarian reaction within groups was also large. Nevertheless, estradiol noticeably increased the proportion of anovulatory cycles; the total number of anovulatory segments was 5, 9 and 19 (out of 24) in the groups "No estradiol", "50 micrograms/24h estradiol" and "100 micrograms/24h estradiol", respectively. A morphometric study of the endometrium indicated a significant decrease in the diameter of glands. This change was due to L-NOG alone, but it seemed to be accentuated by the exogenous estradiol. The occurrence of glandular mitoses increased in both groups receiving estradiol in a dose-dependent manner, indicating an increased endometrial proliferation. The treatment with estradiol did not significantly alter the bleeding pattern.

Pharmacokinetic and pharmacodynamic effects of vaginal rings releasing levonorgestrel at a rate of 27 micrograms/24 hours: a pilot study

The pharmacokinetic and pharmacodynamic effects of vaginal rings releasing levonorgestrel (L-NOG) at an initial rate of 27 micrograms/24 h were studied in a group of 12 normally menstruating women during 90 days of continuous use (i.e., during three 30-day treatment segments). Blood samples were drawn immediately before insertion, 15 and 30 min, as well as 1, 2, 4, 8, 12 and 24 h after insertion of the rings, and thereafter three times weekly throughout the study for the analysis of L-NOG, estradiol, progesterone and sex hormone-binding globulin (SHBG). Endometrial biopsies were obtained for a morphometric analysis in a pre-treatment (control) cycle and in the 6th and 10th weeks of treatment. The peak of average L-NOG levels was reached within two hours after the insertion of rings. Until 24 h after insertion, the levels did not change significantly. Thereafter, a decrease at a rate of 0.2% per day was initiated. The L-NOG and SHBG levels were highly correlated. This was seen for both the pre-treatment SHBG vs L-NOG (r = 0.96) and the treatment SHBG vs L-NOG levels (r = 0.92). There was a significant (p < 0.001) decrease of SHBG levels due to treatment. During the total of 36 treatment segments, a normal ovarian function was seen in 47% of the segments. The women were anovulatory and had an inadequate lutal function in 28% and 25% of segments, respectively. No correlation between the L-NOG levels and ovarian reaction to treatment was found. The use of L-NOG induced significant changes in the endometrium; the number of glands/mm2 decreased after 6 (p < 0.02) and 10 weeks of use (p < 0.01). Also, the diameter of glands and the occurrence of vacuolated cells decreased significantly (p < 0.02 and p < 0.005, respectively). None of the endometrial parameters or dating was correlated with the ovarian reaction to treatment, indicating independent endometrial effects of L-NOG.

Pharmacokinetics of 3-keto-desogestrel and ethinylestradiol released from different types of contraceptive vaginal rings

Pharmacokinetics of 3-keto-desogestrel and ethinylestradiol released from contraceptive vaginal rings (CVRs) with different release rates (75/15, 100/15 and 150/15 micrograms 3-keto-desogestrel/ethinylestradiol daily) were investigated in two studies in young healthy female volunteers. As reference, an oral preparation containing 150 micrograms desogestrel and 30 micrograms ethinylestradiol (MarvelonR tablets) was also administered to the volunteers. To assess the disposition parameters of 3-keto-desogestrel and ethinylestradiol, some of the volunteers were additionally given an i.v. preparation containing 150 micrograms 3-keto-desogestrel and 30 micrograms ethinylestradiol. Serum levels obtained with CVRs showed an initial increase during the first three days, followed by a plateau decreasing only slightly during the remainder of the treatment period. Mean plateau levels (+/- s.d.) of 3-keto-desogestrel were 2.3 +/- 0.9, 2.8 +/- 1.1 and 3.8 +/- 1.1 pmol/ml for CVR 75/15, 100/15 and 150/15, respectively. Mean plateau levels of ethinylestradiol were 184 +/- 75, 262 +/- 102 and 233 +/- 102 pmol/l, respectively. The in vivo release rates of 3-keto-desogestrel and ethinylestradiol from the CVRs were in good agreement with the in vitro release rates. For both steroids the bioavailability from the CVRs was approximately 1.2 times higher than that from the tablets. The 3-keto-desogestrel serum levels were found directly proportional to the release rates within the range studied (75-150 micrograms/day). For ethinylesteradiol the intra-individual variation in steady-state levels was too large to draw pertinent conclusions.

A contraceptive vaginal ring releasing ethinyl estradiol and the progestin ST-1435: bleeding control, serum steroid concentrations, serum lipids and serum chemistry

Four women used vaginal rings releasing the synthetic progestin ST-1435 and ethinyl estradiol for at least three 21-day cycles with a 7-day treatment-free period between intervals of use. Patterns of bleeding were evaluated and serum concentrations of ST-1435, estradiol, progesterone and ethinyl estradiol were measured by radioimmunoassay. Total serum cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides and serum chemistry were determined before ring use and during the first and third treatment cycles. The women experienced no difficulties in using the vaginal ring and all continued to use the ring after the first three cycles. Bleeding control was good and hormonal side effects were minimal. Serum steroid concentrations were: ST-1435, 289 +/- 117 pmol/l (mean +/- SD); ethinyl estradiol, 172 +/- 108 pmol/l; and estradiol, 184 +/- 107 pmol/l. Concentrations of serum progesterone were low, indicating complete suppression of ovulation during treatment. Total serum cholesterol increased slightly during use of ring. However, this increase could be accounted for by an increase in serum HDL-cholesterol. Liver function tests were in the normal range during ring use and values of serum chemistry showed no significant changes. This contraceptive vaginal ring presents a good method of contraception, showing good bleeding control and no harmful metabolic effects.

Microdose intravaginal levonorgestrel contraception: a multicentre clinical trial. I. Contraceptive efficacy and side effects. World Health Organization. Task Force on Long-Acting Systemic Agents for Fertility Regulation

A multicentre clinical trial, including 19 centres in 13 countries, assessed the contraceptive efficacy and clinical acceptability of a Silastic 382 vaginal ring releasing 20 micrograms of levonorgestrel for at least 90 days. A total of 1005 women entered the study and 8176.74 woman-months of experience was gathered. The rate of intrauterine pregnancy at one year of use was 3.6 per 100 women (95% confidence interval 2.2-5.0), and of ectopic pregnancy, 0.2% (one case). The principal reasons for discontinuation were menstrual disturbances (17.2% at one year), vaginal symptoms (6.0%) and repeated expulsion of the ring (7.1%). The pregnancy rate with this 20 micrograms levonorgestrel-releasing vaginal ring compares favourably with that of a low estrogen combination oral contraceptive tested by WHO and is less than half that of a progestogen-only oral contraceptive in a WHO randomized study. It is concluded that the WHO intravaginal ring releasing an average of 20 micrograms of levonorgestrel per 24 hours is an effective method of contraception for at least one year of use.

Does endogenous sex hormone binding globulin influence the contraceptive effect of levonorgestrel?

On the basis of four previous clinical studies a direct relationship of the contraceptive effect of levonorgestrel expressed as a suppression of ovarian function) to individual levels of sex hormone binding globulin may be assumed. The rationale of this dependence seems to be the protection against metabolic degradation which is provided by sex hormone globulin to levonorgestrel.

The interaction between sex hormone binding globulin and levonorgestrel released from Norplant, an implantable contraceptive

Two-hundred-and-eighty Indonesian women were provided with Norplant, a levonorgestrel-releasing implant. At various time intervals, up to 5 years after Norplant insertion, levonorgestrel and sex hormone binding globulin (SHBG) were assayed in blood plasma. After an initial burst of approximately 7 nmol/l, the levels of levonorgestrel rapidly decreased during the first month. The decrease continued to a nadir (1.1 nmol/l) which was reached 10 months later. The decrease was followed by an increase to a broad peak of 1.5 nmol/l which was reached 2 years after insertion. Thereafter, a slow-decrease at a rate of approximately 18 pmol/month was seen. SHBG levels decreased significantly already 1 week after insertion. A nadir of levels (25 nmol/l) was reached 3 months later. The levels increased slowly again and remained constant (32 nmol/l) from about 15 months to 5 years. During the entire period of study highly significant correlations of levonorgestrel with SHBG were seen. In another group of 25 women the levels of levonorgestrel and SHBG were studied before and one week after insertion of Norplant. A significant correlation (r = 0.77) was found between the preinsertion levels of SHBG and postinsertion levels of levonorgestrel.