Feasibility study of Nestorone®–ethinylestradiol vaginal contraceptive ring for emergency contraception

Pharmacodynamic evaluation of the etonogestrel contraceptive implant initiated midcycle with and without ulipristal acetate: An exploratory study

OBJECTIVE

To estimate the incidence of ovulation suppression within five days of etonogestrel 68 mg implant insertion in the presence of a dominant follicle with and without same-day ulipristal acetate.

STUDY DESIGN

This single site non-masked, exploratory randomized trial recruited people age 18-35 years with regular menstrual cycles, no pregnancy risk, and confirmed ovulatory function. We initiated transvaginal ultrasound examinations on menstrual day 7-9 and randomized participants 1:1 to etonogestrel implant alone or with concomitant ulipristal acetate 30 mg oral when a dominant follicle reached ≥14 mm in diameter. We completed daily sonography and serum hormone levels for up to seven days or transitioned to labs alone if sonographic follicular rupture occurred. We defined ovulation as follicular rupture followed by progesterone >3 ng/mL. We calculated point estimates, risk ratios and 95% confidence intervals for ovulation for each group. Ovulation suppression of ≥44% in either group (the follicular rupture suppression rate with oral levonorgestrel emergency contraception), would prompt future method testing.

RESULTS

From October 2020 to October 2022, we enrolled 40 people and 39 completed primary outcome assessments: 20 with etonogestrel implant alone (mean follicular size at randomization: 15.2 mm ± 0.9 mm) and 19 with etonogestrel implant + ulipristal acetate (mean follicular size at randomization: 15.4 mm ± 1.2 mm, p = 0.6). Ovulation suppression occurred in 13 (65%) of etonogestrel implant-alone participants (Risk ratio 0.6 (95% CI: 0.3, 1.1), p = 0.08) and seven (37%) of implant + ulipristal acetate participants.

CONCLUSIONS

Ovulation suppression of the etonogestrel implant alone exceeds threshold testing for future research while the implant + ulipristal acetate does not.

IMPLICATIONS

Data are lacking on midcycle ovulation suppression for the etonogestrel implant with and without oral ulipristal acetate. In this exploratory study, ovulation suppression occurred in 65% of implant participants and 37% of implant + ulipristal acetate participants. Ovulation suppression of the implant alone exceeds threshold testing for future emergency contraception research.

The potential for intramuscular depot medroxyprogesterone acetate as a self-bridging emergency contraceptive

Objective

To examine the rate of ovulatory disruption when intramuscular depot medroxyprogesterone acetate (DMPA) is administered across graded stages of dominant follicle development.

Study design

We assigned enrolled participants to one of three preassigned dominant follicle size groups: 12-14 mm, 15–17 mm and ≥ 18 mm. We followed dominant follicles via serial transvaginal ultrasound (TVUS) until the follicles reached their assigned size, at which time we administered DMPA. For 5 consecutive days thereafter, we followed the follicles via TVUS to observe follicle rupture and obtained serum luteinizing hormone (LH), estradiol, and progesterone concentrations. In the following 2 weeks, we collected serum progesterone concentrations twice weekly to detect possible ovulatory delay or dysfunction. We also collected serum medroxyprogesterone acetate (MPA) concentrations at 1 and 24 h after DMPA administration to examine against ovulatory outcomes.

Results

Twenty-six of 29 enrolled women completed the study. DMPA suppressed ovulation in 17/26 (65%) and caused ovulatory dysfunction in 1/26 (4%) participants. Larger follicles were more likely to rupture despite DMPA (12–14 mm: 0/10 (0%); 15–17 mm: 3/10 (30%); ≥ 18 mm: 6/6 (100%); p < .01). Pre-DMPA LH concentrations ranged from 13.8 to 93.7 IU/L (mean 49.0 IU/L) in cases of follicle rupture. We observed no cases of follicle rupture when DMPA was administered through cycle day 12. All 24-h MPA concentrations exceeded those needed for ovulation suppression.

Conclusion

DMPA suppressed and additionally disrupted ovulation in 65% and 4% of observed cycles, respectively. DMPA may provide effective emergency contraception as well as ongoing contraception if administered prior to an expected ovulation and specifically before the LH surge.

Implications

DMPA may be an alternative form of emergency contraception that can also self-bridge to ongoing contraception. As ovulation was not observed among any follicles when DMPA was given through cycle day 12, women who initiate DMPA up through cycle day 12 may not require backup contraception.

A technology evaluation of Annovera: a segesterone acetate and ethinyl estradiol vaginal ring used to prevent pregnancy for up to one year

INTRODUCTION

The segesterone acetate and ethinyl estradiol contraceptive vaginal ring (SA/EE CVR) was FDA-approved in August 2018 and is now available in the U.S. The CVR is placed vaginally for 21 days followed by a 7-day ring-free interval, when withdrawal bleeding typically occurs. One ring can be used for up to a year (13 cycles).

AREAS COVERED

This review summarizes this novel method of contraception, including the delivery system and the hormonal components. We describe the potential market, how it is used, the pharmacokinetic properties of the device, and results of clinical trials including efficacy, bleeding profile, acceptability, and safety.

EXPERT OPINION

The SA/EE CVR represents the first long-lasting user-controlled hormonal contraceptive device. The bleeding pattern is highly favorable and consistent over the entire year and is associated with very low discontinuation. Efficacy and safety are similar to other methods of combined hormonal contraceptives. Unscheduled ring removals increase the risk of failure. Further studies are needed to evaluate continuous use of the ring for greater than 21 days, and potential non-contraceptive benefits of the ring such as reduced menstrual bleeding.

Systematic Review of Ovarian Activity and Potential for Embryo Formation and Loss during the Use of Hormonal Contraception

The purpose of this review was to determine whether there is evidence that ovulation can occur in women using hormonal contraceptives and whether these drugs might inhibit implantation. We performed a systematic review of the published English-language literature from 1990 to the present which included studies on the hormonal milieu following egg release in women using any hormonal contraceptive method. High circulating estrogens and progestins in the follicular phase appear to induce dysfunctional ovulation, where follicular rupture occurs but is followed by low or absent corpus luteum production of progesterone. Hoogland scoring of ovulatory activity may inadvertently obscure the reality of ovum release by limiting the term "ovulation" to those instances where follicular rupture is followed by production of a threshold level of luteal progesterone, sufficient to sustain fertilization, implantation, and the end point of a positive β-human chorionic gonadotropin. However, follicular ruptures and egg release with subsequent low progesterone output have been documented in women using hormonal contraception. In the absence of specific ovulation and fertilization markers, follicular rupture should be considered the best marker for egg release and potential fertilization. Women using hormonal contraceptives may produce more eggs than previously described by established criteria; moreover, suboptimal luteal progesterone production may be more likely than previously acknowledged, which may contribute to embryo loss. This information should be included in informed consent for women who are considering the use of hormonal contraception.

Summary

For this study, the authors looked at English-language research articles that focused on how hormonal birth control, such as the birth control pill, may affect very early human embryos. The authors found that abnormal ovulation, or release of an egg followed by abnormal hormone levels, may often occur in women using hormonal birth control. This may increase the number of very early human embryos who are lost before a pregnancy test becomes positive. For women who are thinking about using hormonal birth control, this is important information to consider.

Solid state 13C NMR spectroscopy provides direct evidence for reaction between ethinyl estradiol and a silicone elastomer vaginal ring drug delivery system

Steroid molecules have a long history of incorporation into silicone elastomer materials for controlled release drug delivery applications. Previously, based on in vitro release testing and drug content analysis, we demonstrated indirectly that the contraceptive progestin levonorgestrel (LNG) chemically and irreversibly binds to addition cure silicone elastomers, presumably via a hydrosilylation reaction between the levonorgestrel ethynyl group and the hydrosilane groups in the poly(dimethylsiloxane-co-methylhydrosiloxane) crosslinker of the silicone elastomer. Here, for the first time, we report that solid state ¹³C nuclear magnetic resonance (NMR) spectroscopy provides direct evidence for the irreversible binding of ethinyl estradiol (EE) - an estrogenic steroid molecule also containing an ethynyl functional group - to an addition cure silicone elastomer. By preparing silicone elastomer samples containing ¹³C-labelled EE, signals in the NMR spectra could readily be assigned to both the free and bound EE. Additional depolymerisation studies, performed on an addition cure silicone elastomer system from which the unbound EE fraction was completely extracted, further confirmed the presence of bound EE through the formation of coloured reaction mixtures resulting from the reaction of bound EE and trifluoroacetic acid (TFA). These methods will be particularly useful in the ongoing development of new steroid-releasing silicone drug delivery devices, including various vaginal ring devices for contraception, HIV prevention and multipurpose prevention technology applications.

Vaginal rings for delivery of HIV microbicides

Following the successful development of long-acting steroid-releasing vaginal ring devices for the treatment of menopausal symptoms and contraception, there is now considerable interest in applying similar devices to the controlled release of microbicides against HIV. In this review article, the vaginal ring concept is first considered within the wider context of the early advances in controlled-release technology, before describing the various types of ring device available today. The remainder of the article highlights the key developments in HIV microbicide-releasing vaginal rings, with a particular focus on the dapivirine ring that is presently in late-stage clinical testing.

Current status of contraceptive vaginal rings

Contraceptive vaginal rings (CVR) offer a new, effective contraceptive option, expanding the available choices of hormonal contraception. Various ring prototypes have been evaluated: progestin-only rings and combined progestin-estrogen rings, as well as different combination of progestins and estrogens. The progestin-only ring is intended for continuous use, whereas the combined ring has been designed for cyclic 3-week in/1-week out use, although several studies have explored alternative schemes of extended use. However, only two ring designs have reached the market: NuvaRing, a 1-month combined ring that releases etonogestrel and ethinylestradiol, and Progering, a 3-month progesterone-releasing ring for use in lactating women. A one year Nestorone/ethinyl estradiol CVR is approaching the final stages of development, as the Population Council is preparing to submit a new drug application to the Food and Drug Administration. The main advantages of CVRs are their effectiveness (similar or slightly better than the pill), ease of use without the need of remembering a daily routine, user ability to control initiation and discontinuation, nearly constant release rate allowing for lower doses, greater bioavailability and good cycle control with the combined ring, in comparison with oral contraceptives. Current prototypes in development include rings releasing progesterone receptor modulators, which would provide estrogen-free contraception, as well as combined rings releasing estradiol, instead of ethinyl-estradiol, providing a safer profile. Furthermore, intensive efforts towards developing dual protection rings, providing both contraception and protection against reproductive tract infections, offer hope that this greatly needed technology will soon undergo clinical testing and will be in the hands of women worldwide in the near future.

Single-dose pharmacokinetics of Nestorone, a potential female-contraceptive

A synthetic progestin Nestorone is being developed for female-contraception. This study was conducted to determine the distribution, metabolism, and excretion of tritium-labeled Nestorone ((3)H Nestorone) in adult female rats. Rats were injected subcutaneously (S.C.) with a single dose of 400 microCi (3)H Nestorone/kg BW. Its distribution and concentrations in blood, plasma and other tissues were determined at defined times. The excreta were examined for elimination of (3)H Nestorone. Radioactivity in all samples was analyzed by liquid scintillation counter. Metabolite profiling was performed by HPLC and LC/MS analysis of the plasma, urine, and feces samples. Following subcutaneous injection of (3)H Nestorone, the mean peak concentrations of radioactivity (C(max)) in the blood and plasma were 58.1 and 95.5 ng equiv. (3)H Nestorone/g, respectively, at 2-h postdose (T(max)). Thereafter, the concentration of drug steadily declined through 96-h postdose with a terminal elimination half-life (t(1/2)) of 15.6 h. (3)H Nestorone-derived radioactivity was widely distributed in most tissues by 0.5 h and attained a mean maximal concentration by 2-h postdose. Approximately, 81.4% and 7.62% of the administered dose was excreted via feces and urine, respectively. In vivo metabolism of (3)H Nestorone resulted into a total of 19 metabolites. Among them, two metabolites viz., 17alpha-deacetyl-Nestorone (M9) and 4,5-dihydro-17alpha-deacetyl-Nestorone (M19) were identified by HPLC and LC/MS analysis. Metabolite profiling of plasma samples showed that most of the circulating radioactivity was associated with unchanged parent drug, and M19. The M19 was a major metabolite in the profiled urine and feces samples. Presence of large proportion of drug/drug-related material in feces suggested that the biliary excretion is a main elimination route of (3)H Nestorone. The distribution, metabolism, and excretion profiles of (3)H Nestorone obtained in this study provide a fairly good insight about its fate in women.

Does meloxicam increase the incidence of anovulation induced by single administration of levonorgestrel in emergency contraception? A pilot study

BACKGROUND

Levonorgestrel (LNG) consistently prevents follicular rupture only when it is given before the onset of the ovulatory stimulus. As locally synthesized prostaglandin (PG) plays a crucial role in follicular rupture and cyclooxygenase-2 (cox-2) catalyses the final step of PG synthesis, we reasoned that adding a cox-2 inhibitor to LNG would prevent follicular rupture even after the ovulatory process had been triggered by the gonadotrophin surge.

METHODS

Forty-one women were divided into two groups. One was treated when the size of the leading follicle was 15-17 mm (n=10) and the other when it was >or=18 mm (n=31). Each woman contributed with one cycle treated with LNG 1.5 mg single dose plus placebo and another treated with LNG + meloxicam (Melox) 15 mg, in a randomized order. Serial blood sampling for the assay of LH and follicular monitoring by transvaginal ultrasound were performed before and after treatment.

RESULTS

Follicular rupture failed to occur within the 5-day period that followed treatment in 50 and 70% of cycles treated with LNG + Placebo and LNG + Melox, respectively, in the 15-17 mm group (P=0.15) and in 16 and 39% of cycles treated with LNG + Placebo and LNG + Melox, respectively, in the >or=18 mm group (P < 0.052). The overall proportion of cycles with no follicular rupture or ovulatory dysfunction increased significantly by the addition of Melox to LNG (66 versus 88%, P < 0.012; n=41-matched pairs).

CONCLUSIONS

The trend towards increased incidence of no follicular rupture when Melox was combined with LNG suggests that the addition of a cox-2 inhibitor has the potential to improve the contraceptive efficacy of LNG by a pre-fertilization effect.