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

Vaginal ring acceptability: A systematic review and meta-analysis of vaginal ring experiences from around the world

OBJECTIVE

The vaginal ring (ring) is a female-initiated, long-acting drug delivery system for different indications, including HIV prevention. Our aim was to provide evidence for acceptability of the vaginal ring across indications to support dapivirine and multipurpose prevention technology ring introduction and roll out.

STUDY DESIGN

This systematic review and meta-analysis followed PRISMA guidelines. We searched PubMed, Web of Science, Embase, and grey literature for publications reporting favorable ring acceptability and secondary outcomes involving actual ring use (comfort, ease of ring use, ring comfort during sex, expulsions, and vaginal symptoms) or hypothetical acceptability for any indication published January 1, 1970-June 15, 2021. We estimated random-effects pooled prevalence, assessing between-study variation using meta-regression.

RESULTS

Of 2,234 records, we included 123 studies with 40,434 actual and hypothetical ring users. The primary outcome assessment included 50 studies with 60 ring subgroups totaling 19,271 ring users. The favorable acceptability pooled prevalence was 85.6% (95%CI 81.3, 89.0), while hypothetical acceptability among non-ring users was 27.6% (95%CI 17.5, 40.5). In meta-regression, acceptability was higher in menopause (95.4%; 95%CI 88.4, 98.2) compared to contraceptive rings (83.7%; 95%CI 75.6, 89.5). Acceptability was lower in pharmacokinetic studies (50%; 95%CI 22.1, 77.9) compared to RCTs (89.5%; 95%CI 85.8.92.4) and in studies assessing acceptability at ≥12 months (78.5%; 95%CI 66.5, 87.1) versus studies assessing acceptability at <3 months (91.9%; 95%CI 83.7, 96.1). European (90.6%; 95%CI 83.9, 94.7), Asian (97.1%; 95%CI 92.0, 99.0), and multi-region studies (93.5%; 95%CI 84.6, 97.4) reported more favorable acceptability compared to African studies (59.4%; 95%CI 38.3, 77.5). Secondary outcomes were similarly favorable, including ring comfort (92.9%; 95%CI 89.2, 95.4), ease of use (90.9%; 95%CI 86.5, 94.0), and comfort during sex (82.7%; 95%CI 76.4, 87.6). Limitations include inconsistent outcome definitions and unmeasured factors affecting acceptability.

CONCLUSIONS

Women who used vaginal rings reported they were acceptable across indications geographic regions and indications. Policy makers should consider the ring as an important option for pregnancy and HIV prevention drug development.

IMPLICATIONS

This review found favorable acceptability among vaginal ring users across indications and geographic areas, in contrast to low hypothetical acceptability among non-users. Vaginal rings are an important drug delivery system for pregnancy and HIV preventions, and scale-up should plan to address initial hesitancy among new users.

Drug-releasing vaginal rings for HIV/STI and pregnancy prevention: A review of recent advances and clinical applications

INTRODUCTION

Adolescent girls and young women (AGYW), as well as pre- and post-menopausal women globally would benefit from expanded choice to address their sexual and reproductive health (SRH) needs related to Human Immunodeficiency Virus (HIV), sexually transmitted infections (STIs) and pregnancy prevention. Lack of adequate preventative vaccines for HIV/STIs reinforces public health prioritization for options women may use independently to mitigate risk for infectious disease and unplanned pregnancy. Drug releasing intravaginal rings (IVR) represent one such technology that has garnered attention based on the modality's success recently as a pre-exposure prophylaxis (PrEP) delivery option and its impact on reduction in HIV risk.

AREAS COVERED

: This article provides a synopsis of three IVR technologies in active clinical development for prevention of HIV, STI, and unintended pregnancy demonstrating advancements in terms of compatibility with a wide range of drug types with a focus on dapivirine-based silicone rings (International Partnership for Microbicides (IPM), tenofovir-based polyurethane rings (CONRAD), and pod-based rings (Oak Crest Institute of Science).

EXPERT OPINION

The goals of IVR research are to reduce burdens of HIV/STIs and unplanned pregnancies. Through the evolution of IVR technologies, the potential exists to trigger integration of healthcare services through formulation of products with multiple indications.

Development of Hormonal Intravaginal Rings: Technology and Challenges

Intravaginal rings (IVRs) are minimally invasive polymeric devices specifically designed to be used for the sustained and prolonged release of various type of drugs such as hormones. One of the benefits of using topical drug delivery systems (e.g., IVRs) is the fact that systemic drug delivery may cause drug resistance due to elevated drug levels. Topical drug delivery also provides higher concentrations of the drug to the target site and has fewer side effects. In addition, when a drug is administered vaginally, the hepatic first-pass effect is avoided, resulting in higher absorption. Contraception and treatments for specific diseases such as endometriosis and hormone deficiencies can be improved by the administration of hormones via an IVR. This article aims to classify and compare various designs of commercially available and non-commercial hormonal IVRs and to analyze their performance. Current challenges affecting the development of IVRs are investigated, and proposed solutions are discussed. A comprehensive search of publications in MEDLINE/PubMed and of commercial product data of IVRs was performed, and the materials, designs, performance, and applications (e.g., contraception, endometriosis, estrogen deficiency and urogenital atrophy) of hormonal IVRs were thoroughly evaluated. Most hormonal IVRs administer female sex hormones, i.e., estrogen and progestogens. In terms of material, IVRs are divided into 3 main groups: silicone, polyurethane, and polyethylene-co-vinyl acetate IVRs. As regards their design, there are 4 major designs for IVRs which strongly affect their performance and the timing and rate of hormone release. Important challenges include reducing the burst release and maintaining the bioavailability of hormones at their site of action over a prolonged period of administration as well as lowering production costs. Hormonal IVRs are a promising method which could be used to facilitate combination therapies by administering multiple drugs in a single IVR while eliminating the side effects of conventional drug administration methods. IVRs could considerably improve womenʼs quality of life all over the world within a short period of time.

Vaginal ring acceptability and related preferences among women in low- and middle-income countries: A systematic review and narrative synthesis

The vaginal ring (VR) is a female-initiated drug-delivery platform used for different indications, including HIV pre-exposure prophylaxis (PrEP). We conducted a systematic review of VR acceptability, values and preferences among women in low- and middle-income countries (LMIC) to inform further investment and/or guidance on VR use for HIV prevention. Following PRISMA guidelines, we used structured methods to search, screen, and extract data from randomized controlled trials (RCTs) and observational studies reporting quantitative outcomes of acceptability of the VR for any indication published 1/1970-2/2019 (PROSPERO: CRD42019122220). Of 1,110 records identified, 68 met inclusion criteria. Studies included women 15-50+ years from 25 LMIC for indications including HIV prevention, contraception, abnormal bleeding, and menopause. Overall VR acceptability was high (71-98% across RCTs; 62-100% across observational studies), with 80-100% continuation rates in RCTs and favorable ease of insertion (greater than 85%) and removal 89-99%). Users reported concerns about the VR getting lost in the body (8-43%), although actual expulsions and adverse events were generally infrequent. Most women disclosed use to partners, with some worrying about partner anger/violence. The VR was not felt during intercourse by 70-92% of users and 48-97% of partners. Acceptability improved over time both within studies (as women gained VR experience and worries diminished), and over chronological time (as the device was popularized). Women expressed preferences for accessible, long-acting, partner-approved methods that prevent both HIV and pregnancy, can be used without partner knowledge, and have no impact on sex and few side effects. This review was limited by a lack of standardization of acceptability measures and study heterogeneity. This systematic review suggests that most LMIC women users have a positive view of the VR that increases with familiarity of use; and, that many would consider the VR an acceptable future delivery device for HIV prevention or other indications.

Advances in contraceptive vaginal rings: what does the future hold?

INTRODUCTION

Contraceptive vaginal rings (CVRs) are good contraceptive options because they do not require skilled providers, are self-administered, and show a higher stability of drug diffusion.

AREAS COVERED

This article provides a review of the developments made with CVRs over the past number of years, while giving focus to the latest CVRs that have gone through clinical development. The author of the article also provides an expert perspective on the future of these useful therapeutic options.

EXPERT OPINION

Pharmacokinetic studies have shown that segesterone, an absorbable progestin that is used alone or in combination with ethinyl estradiol (EE) or E_2, is the CVR of choice at this present time. Indeed, segesterone has demonstrated safety and efficacy as a CVR and is also an appropriate option for lactating women, as they are not absorbed orally. However, good cycle control is important for improved CVR adherence. CVRs that allow the combination of more than one drug may unravel another multi-purpose use when combined with microbicides and could provide combined protection to women who wish to protect themselves from pregnancy and sexually transmitted infection.

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.

Novel multipurpose pod-intravaginal ring for the prevention of HIV, HSV, and unintended pregnancy: Pharmacokinetic evaluation in a macaque model

Globally, women bear an uneven burden for sexual HIV acquisition. Results from two clinical trials evaluating intravaginal rings (IVRs) delivering the antiretroviral agent dapivirine have shown that protection from HIV infection can be achieved with this modality, but high adherence is essential. Multipurpose prevention technologies (MPTs) can potentially increase product adherence by offering protection against multiple vaginally transmitted infections and unintended pregnancy. Here we describe a coitally independent, long-acting pod-IVR MPT that could potentially prevent HIV and HSV infection as well as unintended pregnancy. The pharmacokinetics of MPT pod-IVRs delivering tenofovir alafenamide hemifumarate (TAF2) to prevent HIV, acyclovir (ACV) to prevent HSV, and etonogestrel (ENG) in combination with ethinyl estradiol (EE), FDA-approved hormonal contraceptives, were evaluated in pigtailed macaques (N = 6) over 35 days. Pod IVRs were exchanged at 14 days with the only modification being lower ENG release rates in the second IVR. Plasma progesterone was monitored weekly to determine the effect of ENG/EE on menstrual cycle. The mean in vivo release rates (mg d-1) for the two formulations over 30 days ranged as follows: TAF2 0.35-0.40; ACV 0.56-0.70; EE 0.03-0.08; ENG (high releasing) 0.63; and ENG (low releasing) 0.05. Mean peak progesterone levels were 4.4 ± 1.8 ng mL-1 prior to IVR insertion and 0.075 ± 0.064 ng mL-1 for 5 weeks after insertion, suggesting that systemic EE/ENG levels were sufficient to suppress menstruation. The TAF2 and ACV release rates and resulting vaginal tissue drug concentrations (medians: TFV, 2.4 ng mg-1; ACV, 0.2 ng mg-1) may be sufficient to protect against HIV and HSV infection, respectively. This proof of principle study demonstrates that MPT-pod IVRs could serve as a potent biomedical prevention tool to protect women's sexual and reproductive health and may increase adherence to HIV PrEP even among younger high-risk populations.

Hormonal contraceptives for contraception in overweight or obese women

BACKGROUND

Obesity has reached epidemic proportions around the world. Effectiveness of hormonal contraceptives may be related to metabolic changes in obesity or to greater body mass or body fat. Hormonal contraceptives include oral contraceptives (OCs), injectables, implants, hormonal intrauterine contraception (IUC), the transdermal patch, and the vaginal ring. Given the prevalence of overweight and obesity, the public health impact of any effect on contraceptive efficacy could be substantial.

OBJECTIVES

To examine the effectiveness of hormonal contraceptives in preventing pregnancy among women who are overweight or obese versus women with a lower body mass index (BMI) or weight.

SEARCH METHODS

Until 4 August 2016, we searched for studies in PubMed (MEDLINE), CENTRAL, POPLINE, Web of Science, ClinicalTrials.gov, and ICTRP. We examined reference lists of pertinent articles to identify other studies. For the initial review, we wrote to investigators to find additional published or unpublished studies.

SELECTION CRITERIA

All study designs were eligible. The study could have examined any type of hormonal contraceptive. Reports had to contain information on the specific contraceptive methods used. The primary outcome was pregnancy. Overweight or obese women must have been identified by an analysis cutoff for weight or BMI (kg/m(2)).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data. One entered the data into RevMan and a second verified accuracy. The main comparisons were between overweight or obese women and women of lower weight or BMI. We examined the quality of evidence using the Newcastle-Ottawa Quality Assessment Scale. Where available, we included life-table rates. We also used unadjusted pregnancy rates, relative risk (RR), or rate ratio when those were the only results provided. For dichotomous variables, we computed an odds ratio with 95% confidence interval (CI).

MAIN RESULTS

With 8 studies added in this update, 17 met our inclusion criteria and had a total of 63,813 women. We focus here on 12 studies that provided high, moderate, or low quality evidence. Most did not show a higher pregnancy risk among overweight or obese women. Of five COC studies, two found BMI to be associated with pregnancy but in different directions. With an OC containing norethindrone acetate and ethinyl estradiol (EE), pregnancy risk was higher for overweight women, i.e. with BMI ≥ 25 versus those with BMI < 25 (reported relative risk 2.49, 95% CI 1.01 to 6.13). In contrast, a trial using an OC with levonorgestrel and EE reported a Pearl Index of 0 for obese women (BMI ≥ 30) versus 5.59 for nonobese women (BMI < 30). The same trial tested a transdermal patch containing levonorgestrel and EE. Within the patch group, obese women in the "treatment-compliant" subgroup had a higher reported Pearl Index than nonobese women (4.63 versus 2.15). Of five implant studies, two that examined the six-capsule levonorgestrel implant showed differences in pregnancy by weight. One study showed higher weight was associated with higher pregnancy rate in years 6 and 7 combined (reported P < 0.05). In the other, pregnancy rates differed in year 5 among the lower weight groups only (reported P < 0.01) and did not involve women weighing 70 kg or more.Analysis of data from other contraceptive methods indicated no association of pregnancy with overweight or obesity. These included depot medroxyprogesterone acetate (subcutaneous), levonorgestrel IUC, the two-rod levonorgestrel implant, and the etonogestrel implant.

AUTHORS' CONCLUSIONS

The evidence generally did not indicate an association between higher BMI or weight and effectiveness of hormonal contraceptives. However, we found few studies for most contraceptive methods. Studies using BMI, rather than weight alone, can provide information about whether body composition is related to contraceptive effectiveness. The contraceptive methods examined here are among the most effective when used according to the recommended regimen.We considered the overall quality of evidence to be low for the objectives of this review. More recent reports provided evidence of varying quality, while the quality was generally low for older studies. For many trials the quality would be higher for their original purpose rather than the non-randomized comparisons here. Investigators should consider adjusting for potential confounding related to BMI or contraceptive effectiveness. Newer studies included a greater proportion of overweight or obese women, which helps in examining effectiveness and side effects of hormonal contraceptives within those groups.

Matrix and reservoir-type multipurpose vaginal rings for controlled release of dapivirine and levonorgestrel

A matrix-type silicone elastomer vaginal ring providing 28-day continuous release of dapivirine (DPV) - a lead candidate human immunodeficiency virus type 1 (HIV-1) microbicide compound - has recently demonstrated moderate levels of protection in two Phase III clinical studies. Here, next-generation matrix and reservoir-type silicone elastomer vaginal rings are reported for the first time offering simultaneous and continuous in vitro release of DPV and the contraceptive progestin levonorgestrel (LNG) over a period of between 60 and 180days. For matrix-type vaginal rings comprising initial drug loadings of 100, 150 or 200mg DPV and 0, 16 or 32mg LNG, Day 1 daily DPV release values were between 4132 and 6113μg while Day 60 values ranged from 284 to 454μg. Daily LNG release ranged from 129 to 684μg on Day 1 and 2-91μg on Day 60. Core-type rings comprising one or two drug-loaded cores provided extended duration of in vitro release out to 180days, and maintained daily drug release rates within much narrower windows (either 75-131μg/day or 37-66μg/day for DPV, and either 96-150μg/day or 37-57μg/day for LNG, depending on core ring configuration and ignoring initial lag release effect for LNG) compared with matrix-type rings. The data support the continued development of these devices as multi-purpose prevention technologies (MPTs) for HIV prevention and long-acting contraception.

Recent advances on anti-HIV vaginal delivery systems development

A review of the recent outcomes regarding technologies to prevent vaginal transmission of HIV, mainly by using antiretroviral (ARV) drugs formulated as microbicides. An introduction about the HIV transmission mechanisms by the vaginal route is included, together with the recent challenges faced for development of successful microbicide products. The outcomes of clinical evaluations are mentioned, and the different formulation strategies studied to-date, with the requirements, advantages, disadvantages and limitations of each dosage-form type, are presented. Finally, the recent attempts to apply various types of nanotechnologies in order to develop advanced microbicide-products and overcome existing limitations, are discussed.

A novel intravaginal ring to prevent HIV-1, HSV-2, HPV, and unintended pregnancy

Women urgently need a self-initiated, multipurpose prevention technology (MPT) that simultaneously reduces their risk of acquiring HIV-1, HSV-2, and HPV (latter two associated with increased risk of HIV-1 acquisition) and prevents unintended pregnancy. Here, we describe a novel core-matrix intravaginal ring (IVR), the MZCL IVR, which effectively delivered the MZC combination microbicide and a contraceptive. The MZCL IVR contains four active pharmaceutical ingredients (APIs): MIV-150 (targets HIV-1), zinc acetate (ZA; targets HIV-1 and HSV-2), carrageenan (CG; targets HPV and HSV-2), and levonorgestrel (LNG; targets unintended pregnancy). The elastomeric IVR body (matrix) was produced by hot melt extrusion of the non-water swellable elastomer, ethylene vinyl acetate (EVA-28), containing the hydrophobic small molecules, MIV-150 and LNG. The solid hydrophilic core, embedded within the IVR by compression, contained the small molecule ZA and the macromolecule CG. Hydrated ZA/CG from the core was released by diffusion via a pore on the IVR while the MIV-150/LNG diffused from the matrix continuously for 94 days (d) in vitro and up to 28 d (study period) in macaques. The APIs released in vitro and in vivo were active against HIV-1ADA-M, HSV-2, and HPV16 PsV in cell-based assays. Serum LNG was at levels associated with local contraceptive effects. The results demonstrate proof-of-concept of a novel core-matrix IVR for sustained and simultaneous delivery of diverse molecules for the prevention of HIV, HSV-2 and HPV acquisition, as well as unintended pregnancy.

Engineering a segmented dual-reservoir polyurethane intravaginal ring for simultaneous prevention of HIV transmission and unwanted pregnancy

The HIV/AIDS pandemic and its impact on women prompt the investigation of prevention strategies to interrupt sexual transmission of HIV. Long-acting drug delivery systems that simultaneously protect womenfrom sexual transmission of HIV and unwanted pregnancy could be important tools in combating the pandemic. We describe the design, in silico, in vitro and in vivo evaluation of a dual-reservoir intravaginal ring that delivers the HIV-1 reverse transcriptase inhibitor tenofovir and the contraceptive levonorgestrel for 90 days. Two polyether urethanes with two different hard segment volume fractions were used to make coaxial extruded reservoir segments with a 100 µm thick rate controlling membrane and a diameter of 5.5 mm that contain 1.3 wt% levonorgestrel. A new mechanistic diffusion model accurately described the levonorgestrel burst release in early time points and pseudo-steady state behavior at later time points. As previously described, tenofovir was formulated as a glycerol paste and filled into a hydrophilic polyurethane, hollow tube reservoir that was melt-sealed by induction welding. These tenofovir-eluting segments and 2 cm long coaxially extruded levonorgestrel eluting segments were joined by induction welding to form rings that released an average of 7.5 mg tenofovir and 21 µg levonorgestrel per day in vitro for 90 days. Levonorgestrel segments placed intravaginally in rabbits resulted in sustained, dose-dependent levels of levonorgestrel in plasma and cervical tissue for 90 days. Polyurethane caps placed between segments successfully prevented diffusion of levonorgestrel into the tenofovir-releasing segment during storage.Hydrated rings endured between 152 N and 354 N tensile load before failure during uniaxial extension testing. In summary, this system represents a significant advance in vaginal drug delivery technology, and is the first in a new class of long-acting multipurpose prevention drug delivery systems.

Multipurpose prevention technologies: products in development

Multipurpose prevention technologies (MPTs) are broadly defined as products capable of simultaneously addressing multiple sexual and reproductive health needs including unintended pregnancy, STIs including HIV-1, and other reproductive tract infections. MPTs have been discussed for a few decades but little product development has occurred. With the recent proof-of-concept that a topically applied antiretroviral (ARV) can effectively reduce sexual transmission of HIV-1 (tenofovir 1% gel) the impetus to develop MPTs is gaining momentum. Products currently in development are broadly categorized as either long-acting or on-demand. Long-acting MPTs include intravaginal rings (IVRs) and long-acting injectable products. Several IVR MPTs are under development including one designed to release tenofovir to prevent transmission of HIV-1 and levonorgestrel (LNG) to prevent unintended pregnancy over a 90-day period. Another MPT IVR under development is designed to release the ARV dapivirine and LNG for 2 months. Long-acting injectable pre-exposure prophylaxis (PrEP) formulations of rilpivirine (TMC278) and GSK1265744 have entered clinical evaluation and could form the basis of long-acting injectable products for HIV-1 prevention and prevention of unintended pregnancy. On-demand products include TFV 1% gel (HIV-1/HSV-2 prevention), a zinc/carrageenan zinc gel (HIV-1/HSV-2 prevention), and the SILCS diaphragm administered with TFV 1% gel. Significant technical, funding, and regulatory hurdles must be overcome to develop most MPTs; however, the significant reproductive health benefits to many women around the world should provide motivation to overcome these hurdles. This article is based on a presentation at the "Product Development Workshop 2013: HIV and Multipurpose Prevention Technologies", held in Arlington, Virginia on February 21-22, 2013. It forms part of a special supplement to Antiviral Research.

Intravaginal rings as delivery systems for microbicides and multipurpose prevention technologies

There is a renewed interest in delivering pharmaceutical products via intravaginal rings (IVRs). IVRs are flexible torus-shaped drug delivery systems that can be easily inserted and removed by the woman and that provide both sustained and controlled drug release, lasting for several weeks to several months. In terms of women's health care products, it has been established that IVRs effectively deliver contraceptive steroids and steroids for the treatment of postmenopausal vaginal atrophy. A novel application for IVRs is the delivery of antiretroviral drugs for the prevention of human immunodeficiency virus (HIV) genital infection. Microbicides are antiviral drugs delivered topically for HIV prevention. Recent reviews of microbicide IVRs have focused on technologies in development and optimizing ring design. IVRs have several advantages, including the ability to deliver sustained drug doses for long periods of time while bypassing first pass metabolism in the gut. IVRs are discreet, woman-controlled, and do not require a trained provider for placement or fitting. Previous data support that women and their male sexual partners find IVRs highly acceptable. Multipurpose prevention technology (MPT) products provide protection against unintended/mistimed pregnancy and reproductive tract infections, including HIV. Several MPT IVRs are currently in development. Early clinical testing of new microbicide and MPT IVRs will require a focus on safety, pharmacokinetics and pharmacodynamics. Specifically, IVRs will have to deliver tissue concentrations of drugs that are pharmacodynamically active, do not cause mucosal alterations or inflammation, and do not change the resident microbiota. The emergence of resistance to antiretrovirals will need to be investigated. IVRs should not disrupt intercourse or have high rates of expulsion. Herein, we reviewed the microbicide and MPT IVRs currently in development, with a focus on the clinical aspects of IVR assessment and the challenges facing microbicide and MPT IVR product development, clinical testing, and implementation. The information in this review was drawn from PubMed searches and a recent microbicide/MPT product development workshop organized by CONRAD.

Pharmacokinetics of a multipurpose pod-intravaginal ring simultaneously delivering five drugs in an ovine model

Multipurpose technologies that simultaneously protect from sexually transmitted infections and unintended pregnancy are urgently needed. Pod-intravaginal rings (IVRs) formulated with the antiretroviral agents (ARVs) tenofovir, nevirapine, and saquinavir and the contraceptives etonogestrel and estradiol were evaluated in sheep. Steady-state concentrations were maintained for 28 days with controlled, sustained delivery. This proof-of-principle study demonstrates that pod IVRs can deliver three ARVs from different mechanistic classes and a progestin-estrogen combination over the wide range needed for putative preventative efficacy.

Hormonal contraceptives for contraception in overweight or obese women

BACKGROUND

Obesity has reached epidemic proportions around the world. Effectiveness of hormonal contraceptives may be related to metabolic changes in obesity or greater body mass or body fat. Hormonal contraceptives mainly include oral contraceptives, injectables and implants, the transdermal patch, and the vaginal ring. We systematically reviewed the evidence on the effectiveness of hormonal contraceptives among overweight and obese women.

OBJECTIVES

To examine the effectiveness of hormonal contraceptives in preventing unplanned pregnancies among women who are overweight or obese versus women of lower weight or body mass index (BMI).

SEARCH METHODS

Through January 2013, we searched MEDLINE, CENTRAL, POPLINE, ClinicalTrials.gov, and ICTRP. The previous search also included EMBASE. We contacted investigators to identify other trials.

SELECTION CRITERIA

All study designs were eligible. Any type of hormonal contraceptive could have been examined. Reports had to contain information on the specific contraceptive method(s). The primary outcome was pregnancy. Overweight or obese women must have been identified by an analysis cutoff for weight or BMI (kg/m(2)).

DATA COLLECTION AND ANALYSIS

Data were abstracted by two authors. Life-table rates were included where available. For dichotomous variables, we computed an odds ratio with 95% confidence interval (CI). We used reported pregnancy rates or relative risk (RR) when those were the only results provided. The main comparisons were between overweight or obese women and women of lower weight or BMI. We assessed the quality of evidence for this review.

MAIN RESULTS

We found nine reports with data from 13 trials that included a total of 49,712 women. Five reports from 2002 to 2012 compared BMI groups; of those, one reported a higher pregnancy risk for overweight or obese women. In that trial, women assigned to an oral contraceptive containing norethindrone acetate 1.0 mg plus EE 20 µg and having a BMI at least 25 had greater pregnancy risk compared to those with BMI less than 25 (reported RR 2.49; 95% CI 1.01 to 6.13). The comparisons reported in the other four studies were not significantly different for pregnancy. These included studies of a combined oral contraceptive (COC), a transdermal patch, an implant, and an injectable. The COC study showed no trend by BMI or weight. With the transdermal patch, body weight was associated with pregnancy (reported P < 0.001) but BMI was not. The implant study had one pregnancy and the injectable study reported no pregnancies.Four studies from the 1990s used weight alone rather than BMI. Results were mixed. Studies of a vaginal ring (never marketed) and a six-rod implant showed higher pregnancy rates for women weighing at least 70 kg versus those weighing less than 70 kg (reported P values: 0.0013 and < 0.05, respectively). However, two implant studies showed no trend by body weight.

AUTHORS' CONCLUSIONS

The evidence did not generally show an association of BMI with effectiveness of hormonal contraceptives. However, the evidence was limited for any individual contraceptive method. Studies using BMI (rather than weight alone) can provide more information about whether body composition is related to contraceptive effectiveness. The efficacy of subdermal implants and injectable contraceptives may be unaffected by body mass. The contraceptive methods examined here are among the most effective when the recommended regimen is followed.The overall quality of evidence was low for this review. More recent reports provided moderate quality evidence, while the older studies provided evidence of low or very low quality for our purposes. Investigators should consider adjusting for potential confounding related to BMI. Trials should be designed to include sufficient numbers of overweight or obese women to adequately examine effectiveness and side effects of hormonal contraceptives within those groups.

The vagina as a route for drug delivery: a review

Overactive bladder (OAB) syndrome has a significant deleterious impact on quality of life. After conservative therapy and bladder retaining, antimuscarinic drugs remain the mainstay of OAB management. Oral therapy is associated with frequent side effects, leading to the development of alternative agents and formulations or the use of novel routes of drug administration, such as the vaginal route. The vagina is often ideal for drug delivery because it allows the use of lower doses, maintains steady drug administration levels, and requires less frequent administration than the oral route. With vaginal drug administration, absorption is unaffected by gastrointestinal disturbances, there is no first-pass effect, and use is discreet. The aim of this review is to provide a background overview of vaginal development, anatomy, and physiology and the effect this has on the use of this route for both local and systemic drug delivery, with special reference to OAB management. Vaginal therapy continues to be an underused route of drug delivery. Vaginal administration allows nondaily, low, continuous dosing, which results in stable drug levels and may, in turn, achieve a lower incidence of side effects and improve patient compliance. These benefits must be balanced against inherent patient or physician bias against using this route and the need to overcome cultural, personal, and hygiene-related barriers to this form of therapy. More sophisticated and programmable vaginal rings are being developed for systemic delivery of therapeutically important macromolecules, such as antimuscarinic therapy in OAB management.

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.

Future strategies in microbicide development

The reduction in human immunodeficiency virus (HIV) infection in women demonstrated by pericoital use of tenofovir gel has encouraged the continued development of microbicides. Novel approaches include new ways to deliver tenofovir, as well as products that contain different antiretroviral drugs, either as single agents or as combinations of antiretroviral drugs. Indeed, emphasis has renewed on the development of multipurpose prevention technologies, products designed to address multiple sexually transmitted infections. Dual-purpose contraceptive antiretroviral products are also being designed to prevent HIV and pregnancy. Since consistent and correct use of these products will be critical to their effectiveness, the active pharmaceutical ingredients must be delivered in acceptable vaginal dosage forms, such as gels, films and sustained-release vaginal rings. The development of different dosage forms will help ensure that women can find a method to protect themselves from HIV, pregnancy, and potentially other sexually transmitted infections.

Multipurpose prevention technologies: biomedical tools to prevent HIV-1, HSV-2, and unintended pregnancies

Statistics clearly show an unmet need for highly effective contraception, especially in less developed countries. Many of these countries are at the core of the HIV/AIDS epidemic and show very high prevalence rates for other sexually transmitted infections (STIs) such as that caused by HSV-2. A woman at risk of unintended pregnancy due to unprotected intercourse is also at risk for HIV/STI. Owing to their causative interrelationship, combining protection against these conditions will result in enhanced prevention and health benefits. Existing multipurpose prevention modalities such as condoms and physical barriers, albeit efficacious, face cultural hurdles that have so far hindered their widespread use. Success has recently been demonstrated in large clinical trials, demonstrating proof of concept of microbicides in reducing the incidence of HIV-1 and HSV-2 among at-risk populations. The challenge heretofore is to refine these products to make them more potent, convenient, accessible, and acceptable. Potent antiviral drugs released topically in the female reproductive tract by innovative delivered systems and formulations will provide safe, effective, and acceptable multipurpose prevention tools. This paper provides an overview of existing and novel approaches to multipurpose prevention strategies.

Hormonal contraceptives for contraception in overweight or obese women

BACKGROUND

Obesity has reached epidemic proportions around the world. Metabolic changes in obesity and greater body mass may lead to reduced effectiveness of hormonal contraceptives, such as the skin patch, vaginal ring, implants, and injectables. We systematically reviewed the evidence on the effectiveness of hormonal contraceptives among overweight and obese women.

OBJECTIVES

To examine the effectiveness of hormonal contraceptives in preventing unplanned pregnancies among women who are overweight or obese versus women of lower weight or body mass index (BMI).

SEARCH STRATEGY

We searched MEDLINE, CENTRAL, POPLINE, EMBASE, ClinicalTrials.gov, and ICTRP. We also contacted investigators to identify other trials.

SELECTION CRITERIA

All study designs were eligible. Any type of hormonal contraceptive could have been examined. The primary outcome was pregnancy. Overweight or obese women must have been identified by an analysis cutoff for weight or BMI (kg/m(2)).

DATA COLLECTION AND ANALYSIS

Data were abstracted by two authors; life-table rates were included where available. For dichotomous variables, we computed an odds ratio with 95% confidence interval. The main comparisons were between overweight or obese women and women of lower weight or BMI.

MAIN RESULTS

We found 7 reports with data from 11 trials that included 39,531 women. One of three studies using BMI found a higher pregnancy risk for overweight or obese women. In the trial of two combination oral contraceptives, women with BMI >= 25 had greater pregnancy risk compared to those with BMI < 25 (OR 1.91; 95% CI 1.01 to 3.61). Among skin patch users, body weight was associated with pregnancy (reported P < 0.001) but BMI was not. Studies of a vaginal ring (never marketed) and a six-rod implant showed higher pregnancy rates for women weighing >= 70 kg versus those weighing < 70 kg (reported P values: 0.0013 and < 0.05, respectively). However, two implant studies showed no trend by body weight, and trials of an injectable had no pregnancies.

AUTHORS' CONCLUSIONS

Body weight addresses overall body size, while BMI generally reflects the amount of fat. Only one of three studies using BMI found a higher pregnancy risk for overweight women. The efficacy of implants and injectable contraceptives may be unaffected by body mass. The field could use trials of contraceptive methods with groups stratified by BMI. The current evidence on effectiveness by BMI is limited. However, the contraceptive methods examined here are still among the most effective when the recommended regimen is followed.

Pharmacokinetic study to compare the absorption and tolerability of two doses of levonorgestrel following single vaginal administration of levonorgestrel in Carraguard gel: a new formulation for "dual protection" contraception

OBJECTIVE

The study was conducted to assess levonorgestrel (LNG) serum levels achieved after a single administration of two different doses of Carraguard vaginal gel containing LNG (CARRA/LNG), designed for use as microbicide and contraceptive for potential dual protection.

MATERIALS AND METHODS

This was a randomized double-blind pharmacokinetic study conducted in 12 subjects enrolled at two centers. Each subject received a single vaginal administration of CARRA/LNG containing either 0.75 or 1.5 mg LNG per 4 mL of gel on Days 10-12 of the menstrual cycle. LNG serum levels were measured at 0, 1, 2, 4, 8 and 12 h after administration and for the following 7 days. LH and progesterone (for a preliminary evaluation of effect on the ovarian function) as well as SHBG were measured in the daily samples.

RESULTS

Serum LNG maximum concentrations (Cmax) were 14.1+/-2.1 and 11.7+/-2.7 nmol/L and Tmax was 12.0 and 6.0 h for the low and high dose, respectively, with large intersubject variability within the first 48 h. Mean levels at 96 h were 10% of Cmax. Differences in AUC between both doses were not statistically significant. SHBG levels decreased approximately 25% by Day 4 after administration. Luteal activity was observed in 3/6 and 5/6 of the subjects in the low- and high-dose group, respectively.

CONCLUSION

This study demonstrates that the CARRA/LNG gel can sustain elevated serum levels of the contraceptive steroid for up to 96 h after a single application. The serum levels attained with the 0.75-mg formulation are in the range expected to perturb the ovulatory process as observed in some subjects. The lack of correlation between the administered dose and serum concentrations of the steroid may be related to a rate-limiting absorption of LNG from the vaginal mucosa. The results reported here suggest that the CARRA/LNG formulation has good potential to become a dual-protection method, possibly preventing conception and sexually transmitted infections.

Vaginal delivery of contraceptives

Although a steady increase in contraceptive use has been observed both in developed and less-developed countries, the large number of unplanned pregnancies may indicate that the contraceptive needs of a significant percentage of couples have so far not been met. Several new contraceptive products have reached the market during the last 2 years. Among these is a new contraceptive vaginal ring, which has become available for prescription. This new female method has been developed to expand the contraceptive choices available to couples. This review will address the specifics of the vaginal route for delivering contraceptive steroids and describe the various systems available or under evaluation.

Role of progestins in contraception

Progestins have been used for contraception for more than 30 years. The main goal was to develop a contraceptive method devoid of the metabolic or clinical side-effects associated with the use of estrogens. The development of new contraceptive methods and formulations is time-consuming and requires devotion, belief, and also strong economical basis. As a result of this endeavor new methods have been developed: oral progestins, implants, injectables, intrauterine hormonal systems, and vaginal rings. Progestin-only contraceptives may be preferable in some situations, which have absolute or relative contraindications to estrogen, side-effects to estrogen containing hormonal contraception, lactation, and comfort and feasibility of formulations for long-term use. At present, emergency contraception is also performed with progestin.

Why consider vaginal drug administration?

OBJECTIVE

To review the anatomy and physiology of the vagina, the merits of vaginal drug administration, and the currently available vaginal drug-administration systems.

DESIGN

Review of basic and clinical research.

RESULT(S)

Although clinicians commonly use topically administered drugs in the vagina, this route for systemic drug administration is somewhat novel. Experience with a variety of products demonstrates that the vagina is a highly effective site for drug delivery, particularly in women's health. The vagina is often an ideal route for drug administration because it allows for the administration of lower doses, steady drug levels, and less frequent administration than the oral route. With vaginal drug administration, absorption is unaffected by gastrointestinal disturbances, there is no first-pass effect, and use is discreet. Knowledge of anatomy, physiology, histology, and immunology of the vagina should allow clinicians to reassure their patients concerning this mode of delivery. Greater understanding and experience by clinicians should lead to increased use and acceptance of the vagina as a route for drug administration.

CONCLUSION(S)

The safety and efficacy of vaginal administration have been well established. The vaginal route of drug delivery is acceptable and may even be a preferable route of administration for many drugs, particularly hormones, whether for contraception or postmenopausal estrogen therapy.

A randomized comparison of the effects on vaginal and cervical epithelium of a placebo vaginal ring with non-use of a ring

Little is known about the effects of contraceptive vaginal rings on the vaginal surface epithelium, although most studies have not demonstrated any significant deleterious effect. However, one study found that some medium-to-long-term levonorgestrel-releasing ring users developed chronic erythematous and ulcerative lesions in the posterior vaginal fornix. Subsequently, this ring was completely redesigned (IVR-2) with different dimensions and much greater flexibility. The first version of IVR-2 was designed as a placebo ring to explore effects on the vagina and cervix without addition of a progestogen. One-hundred-sixty-six healthy sexually active women volunteers were recruited in four centers and randomly assigned for 6 months to either placebo ring use or control (non-use) using a predetermined randomization code generated by WHO in a 2:1 ratio. Careful inspections of the vaginal and cervical epithelium were performed with a colposcope at admission and at 2-month intervals. No clinically significant lesions were detected in any center either among ring users or controls. However, a number of minor changes in appearance of the vaginal and cervical epithelium (erythema, petechiae, ecchymosis, and minor aceto-white changes) were described from the Sydney Center, some of which were present on admission and some of which were found on subsequent examination. Ten of eleven "red" changes on the cervix and vagina were noted in IVR-2 users, and only one in the controls, suggesting a contribution by the IVR-2 to minor epithelial surface changes. Five of ten resolved completely with continued ring use. There was no correlation in this study between epithelial changes and cigarette smoking or frequency of intercourse in the 14 days prior to colposcopic examination but a significant relationship between tampon use in the last 7 days and all epithelial changes (p = 0.05) and especially red changes (p = 0. 027) was noted. Red changes were significantly less likely to be found among condom users (p = 0.007). The IVR-2 placebo ring did not produce clinically significant changes in the vaginal epithelium and cervical mucosa and a carefully controlled and randomized study should be considered to compare the epithelial appearances in women using a placebo IVR-2 and one releasing 20 microg levonorgestrel.

Vaginal epithelial surface appearances in women using vaginal rings for contraception

Vaginal inspections using colposcopy before insertion of contraceptive vaginal rings and at 2-month intervals during ring use were conducted on 169 users of four different formulations. The rings studied released Nestorone alone (50, 75, 100 g daily over 6 months); ethinyl estradiol: Nestorone (30:100 and 15:150 g daily over 6 months); ethinylestradiol:norethindrone acetate (20:1000 and 15:1000 g daily over 4 months); and ethinyl estradiol:norethindrone acetate (20:1000 g daily over 12 months). A total of 88 altered or atypical conditions of the vaginal surface appearance were recorded in 507 inspections (17.4% of inspections). Many of these atypical appearances were quite subtle. The incidence was significantly higher (p <0.01) than in the single pretreatment examinations (11 in 158 inspections; 7.0%), but closely matched that of a "control group" of sexually active women who were the subject of an earlier study by the same investigators. In that study, the incidence was 18% (57 atypical conditions in 317 inspections). In all, 83% of atypical conditions identified in the vagina during ring use had disappeared by the next scheduled colposcopy despite continued ring use. Findings of potential significance were conservatively defined as all ulcerations, those abrasions and ecchymoses that were >0.5 cm in any direction, and fields of five or more petechiae. Findings fitting those criteria comprised 30% of atypical conditions in ring users, 33% in the control group, and 27% pretreatment. The corresponding incidence as a percentage of inspections were 5.3%, 6. 0%, and 2.5% in the ring users, control groups, and pretreatment groups, respectively. These differences were not statistically significant. The findings suggest that the vaginal rings included in the studies contributed little, if at all, to clinically significant lesions or to total lesion incidence. Further definition would require a larger and longer-term study with matched controls.

Variations in vaginal epithelial surface appearance determined by colposcopic inspection in healthy, sexually active women

A total of 107 sexually active women, aged 18-35 years, was recruited through family planning clinics in four centres in different countries. Each woman underwent two or three gentle but thorough and systematic vaginal inspections using a consistent technique with colposcopic magnification over a 4-6 month period to look for changes in vaginal and cervical appearance which might be related to sexual intercourse, tampon use, contraceptive method used, cigarette smoking or other environmental factors. Obvious changes in appearance were photographed at x10 magnification. These 'appearances' or 'conditions' were classified according to a modification of the recommendations of a workshop sponsored by the World Health Organization, the Population Council and the Conrad Program. Most of these alterations in the appearance of the vaginal epithelium were judged to be of such minor clinical importance that they have been termed 'conditions' or 'changes in appearance' rather than 'lesions'. In all, 56 'conditions' or 'appearances' were noted in 314 inspections, the commonest being petechiae (53.6%). Potentially significant conditions justifying the term 'lesions' (three microulcerations, two ecchymoses, five abrasions and one mucosal tear; 3.5% of inspections) usually healed spontaneously and disappeared rapidly. The incidence of these conditions was highest when the inspections followed intercourse in the previous 24 h (25.2 versus 14.2%; P < 0.0008), or tampon use (32.4 versus 15.9%; P < 0. 0001). These processes may be regarded as a reflection of regular minor trauma to the vaginal epithelium.

The comparative trial of TCu 380A IUD and progesterone-releasing vaginal ring used by lactating women

The objective of this paper was to compare the efficacy, acceptability, safety, and bleeding pattern of TCu 380A intrauterine device (IUD) and progesterone-releasing vaginal ring used by breastfeeding women. The study population included 97 breastfeeding women using IUD and 100 women using vaginal ring. Of the IUD users, no insertion failure, perforation, or accidental pregnancy occurred in 12 months. There was one IUD expulsion. There were no discontinuations of IUD due to medical reasons other than expulsion. The total discontinuation rate was 2.3%. In the ring group, no accidental pregnancy occurred. The major reasons for discontinuation were ring use-related problems and vaginal problems. The total discontinuation rate was 65.4% within 1 year. The frequency of any one complaint among the ring users was higher than that among the IUD users. There were no differences in the proportion of women having no sexual activity and in the weight of their babies between the two groups. Compared with the IUD users, the median number of bleeding/spotting (B/S) episodes and B/S days of the vaginal ring users were fewer; consequently, the mean length of B/S-free interval was longer in all four reference periods; the mean length of B/S episode and segment were the same; the occurrence of amenorrhea was more frequent; in contrast, the proportions of normal bleeding patterns were fewer. The frequencies of prolonged bleeding, frequent bleeding, and infrequent bleeding patterns did not differ between the two groups. The percentage of irregular bleeding was fewer only in the first two reference periods. It is concluded that the TCu 380A IUD and progesterone-releasing vaginal ring used by breastfeeding women are safe and effective. The higher discontinuation rate of the ring users was mainly because of use-related problems. Breastfeeding women with TCu 380A IUD had better tolerance and acceptability. The TCu 380A IUD does not, but the progesterone-releasing vaginal ring does, suppress the recovery of ovarian function. However, once return of menstruation occurred, there were no differences in bleeding patterns between the two contraceptive methods.

Effect of different insertion regimens on side effects with a combination contraceptive vaginal ring

The study population included 159 women aged 18 to 37 years requiring contraception (60 in Sydney, 99 in Los Angeles). The design consisted of a 6 month study of a contraceptive vaginal ring (CVR) releasing 20 micrograms ethinyl estradiol and 1 mg of norethindrone acetate daily over two successive cycles with a new ring on each of three different insertion regimens. A total of 831 woman-months of exposure were recorded, and 129 women completed the study. The overall incidence of side effects was similar in the two centers and differences between the insertion regimens were not observed. Transient nausea following insertion of a new ring (mainly lasting 0.5 to 48 h) was the most prominent side effect, with no significant difference between the insertion regimens (although the incidence tended to be highest with bedtime insertion [34%] and lowest with early evening insertion and temporary removal during the first night [27%]). Transient vomiting occurred in about 10% of women in the first 24 h after first insertion of a new ring. The incidence and severity of nausea was greatly reduced in cycle 2 with each regimen (6% to 9% of women). Nausea could be prevented by overnight soaking of the ring in water before use. Other side effects such as headache, dizziness, uterine cramps, breakthrough bleeding, weight gain, and ring expulsion occurred with similarly low frequency in all three insertion groups. One pregnancy occurred with probable ovulation between cycles 5 and 6, the only pregnancy recorded to date in studies with this ring. The study demonstrated that this effective and generally well tolerated CVR causes a relatively high incidence of transient nausea after insertion of a new ring, which is probably due to accumulation of ethinyl estradiol on the ring surface during storage. Acceptability is still high, and this particular CVR merits further development.

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.

Vaginal contraceptive rings

Steroids diffuse through polysiloxone at a constant rate, and steroids placed in the vagina rapidly pass through the vaginal epithelium into the circulation. Combining these principles led to the development of contraceptive vaginal rings (CVR) consisting of various progestins, with and without oestrogen, placed in flexible polysiloxone, doughnut-shaped devices. As occurs with oral contraceptives, the CVRs containing progestin plus oestrogen are left in the vagina for 3 weeks and removed for 1 week to allow withdrawal bleeding, while CVRs releasing a small dose of progestins without oestrogen are left in the vagina continuously for several months. Large-scale, clinical trials were performed with a low dose levonorgestrel-releasing-only CVR by the WHO. At 1 year, continuation rates were about 50 per 100 women with 17.2 per 100 discontinuing for menstrual problems and 4.5 for pregnancy. Two sizes of a CVR containing levonorgestrel and oestradiol were studied in a multinational trial organized by the Population Council. At the end of 1 year, about half the women were continuing with the method, one-quarter had discontinued because of bleeding problems, and pregnancy rates were between 1 and 2 per 100 women. The CVR was well accepted by women and their partners, but because of lowered HDL-cholesterol levels and accelerated atherosclerosis in female monkeys, further development of this formulation was discontinued. Recently, phase II clinical trials with CVRs containing combinations of NET-acetate plus ethinyloestradiol and 3-ketodesogestrel plus ethinyloestradiol have been undertaken. These CVRs provide good bleeding control, inhibit ovulation consistently and do not have an adverse effect on serum lipids. Phase III trials with these two types of CVRs will be initiated shortly.

Evaluation of four different contraceptive vaginal rings: steroid serum levels, luteal activity, bleeding control and lipid profiles

Four different models of contraceptive vaginal rings were tested during three cycles for luteal activity, bleeding control, plasma lipoproteins and serum levels of the contraceptive steroids. Two progestins, levonorgestrel acetate (LNGA) and ST 1435, alone or in combination with ethynyl-estradiol (EE) were tested. The rings released 100 ug/day of the progestins and 30 ug/day of EE. Luteal activity was detected among users of the progestin-only rings: 4 of 8 cycles with ST 1435 and 2 of 10 with LNGA. Only one of the 18 cycles studied with the two combined rings showed luteal activity, but the measurement of contraceptive steroid in plasma suggested that this subject delayed reinsertion of the ring for about one week in that particular cycle. Breakthrough bleeding was observed in 12 of 30 cycles of use of the progestin-only rings, and in only 2 of 27 cycles with the combined models. No significant changes in total cholesterol or its HDL-fraction were observed. However, the only reduction observed in HDL-cholesterol was among users of the LNGA-only ring. It is concluded that the two combined CVR models offer good possibilities of high effectiveness and bleeding control and merit further development.

The progestin-only oral contraceptive--its place in postpartum contraception

The progestin-only oral contraceptive (POC) is not a widely-used method of contraception, possibly due to competition from other contemporary contraceptive methods or misunderstanding and prejudices among clients and/or service providers. Because of its underuse, the POC, as a contraceptive method, is under-studied. This article evaluates the general merits of the POC and its disadvantages relative to combined oral contraceptives (COCs) and other contraceptive methods, specifically during the postpartum period and particularly for breastfeeding women. We find that the POC appears to be a safe and acceptable contraceptive method for postpartum women who are fully or nearly fully breastfeeding at six months postpartum or when menstruation returns. The POC could be considered for use at any time by non-breastfeeding postpartum women. The need for empirical studies of the POC is also discussed.

The effects of a combined contraceptive vaginal ring releasing ethinyloestradiol and 3-ketodesogestrel on vaginal flora

Fifty nine women with documented normal ovulatory cycles and with no symptoms of vaginal infection were divided into four groups. Each group used a combined contraceptive vaginal ring (CCVR) with a mean daily release rate of 0.015 mg of ethinyloestradiol (EE) and 0.120 mg of 3-ketodesogestrel (3-KDG) per day, for one cycle of either 21, 28, 42, or 56 days. Cultures from the posterior vaginal fornix and from the endocervical canal were obtained immediately before insertion of the ring and on removal of the ring. Changes in the numbers of vaginal cells, aerobic and anaerobic bacteria, Chlamydia trachomatis, Gardnerella vaginalis, yeasts and Trichomonas vaginalis were documented at the end of each treatment. Intra- and inter- group changes in the vaginal flora were assessed at the end of each treatment. The comparison between the number and type of flora showed no significant change between the pre-treatment population and the post-treatment population. The results of this study suggest that the use of this CCVR for 21, 28, 42 and 56 days is not associated with an increase in inflammatory cells or pathogenic bacteria.