Different Pearl Indices in studies of hormonal contraceptives in the United States: impact of study population

Motivators for emergency contraception: Previous pregnancy and condom rupture

Objectives

Little is known about the motivations to apply for emergency contraception (EC). Our first aim was to explore the motivating circumstances to use EC as fast as possible. Our second aim was to explore the contraceptive method of the population seeking EC.

Study design

This present retrospective observational study between July 2021 and September 2021 is embedded in the MEEC (Motivation and Epidemiology of Emergency Contraceptive Pill) based on the study cohort of a Hungarian data bank containing follow-up data of 455 women applied for EC telemedicine consultation. Variables assessed were: age, gynecological history (pregnancies, abortions, miscarriages), data of the intercourse (elapsed time, contraceptive method), and data of the menstrual cycle, and relationship status.

Results

Of all patients, 59.3 % reported condom rupture, 29.5 % no protection, and 11.2 % other. Patients using condom applied for EC significantly sooner than those using no protection and using other protective methods. A significantly shorter elapsed time was observed in patients with a history of a previous pregnancy. No significant relationship was seen between the way of protection, previous pregnancies, and surprisingly the time of ovulation despite the obvious intention of avoiding pregnancy.

Conclusions

This is the first study to examine the potential role of epidemiologic factors as motivators for EC on the basis of a large patient cohort. Our study demonstrates the significant role of condom rupture/use and the history of previous pregnancies to be the strongest motivators for EC.

Pooled efficacy results of estetrol/drospirenone combined oral contraception phase 3 trials

OBJECTIVE

To evaluate overall and subgroup efficacy of an estetrol (E4) 15 mg drospirenone (DRSP) 3 mg oral contraceptive in a 24/4-day regimen.

STUDY DESIGN

We pooled efficacy outcomes from 2 pivotal phase 3 contraceptive trials with E4/DRSP conducted in the United States/Canada and Europe/Russia. We assessed Pearl Index (PI; pregnancies per 100 participant-years) and 13-cycle life-table pregnancy rates in at-risk cycles (confirmed intercourse and no other contraceptive use) among participants 16 to 35 years. We calculated PI by age and further subcategorization (contraceptive history and body mass index [BMI]). We performed multivariable analysis using Cox regression to assess impact of potential confounding factors.

RESULTS

Analyses included 3027 participants, of whom 451 (14.9%) had a BMI ≥30 kg/m². The pooled PI was 1.52 (95% confidence interval 1.04-2.16) and the 13-cycle life-table pregnancy rate was 1.28% (0.83%-1.73%). We calculated unadjusted pooled PI in participants 16 to 25 years and 26 to 35 years of 1.61 (0.94-2.57) and 1.43 (0.78-2.40), respectively; in new starters and switchers of 1.88 (1.09-3.00) and 1.24 (0.68-2.08), respectively; and by BMI <25 kg/m², 25 to 29.9 kg/m², and ≥30 kg/m² of 1.14 (0.64-1.88), 2.19 (1.05-4.03), and 2.27 (0.83-4.94), respectively. In multivariable analysis, we found associations of prior pregnancy (hazard ratio [HR] 3.61[1.56-8.38]), Black race (HR 4.61[1.97-10.80]), age 16 to 25 years (HR 2.37[1.09-5.15]) and compliance <99% of expected pills (HR 4.21[2.04-8.66]) with conception.

CONCLUSION

E4/DRSP is an effective oral contraceptive overall and across subgroups stratified by age, contraceptive history, and BMI. Other than compliance, predictors of contraceptive failure are nonmodifiable.

IMPLICATIONS STATEMENT

Pooled results from two phase 3 trials demonstrate high contraceptive efficacy of the novel estetrol-drospirenone oral contraceptive. Several non-modifiable risk factors, including prior pregnancy, race, and age, are associated with higher pregnancy risk. Additional research is needed to better understand predictors of combined oral contraceptive failure.

Estetrol/Drospirenone: A Review in Oral Contraception

Estetrol/drospirenone is a combined oral contraceptive (COC) with a plant-synthesised foetal oestrogen (estetrol) and a well-established progestin (drospirenone). In preclinical models, estetrol has lower binding affinity for the oestrogen receptor-α (ER-α) in contrast to estradiol and has antagonistic properties against membrane ER-α in several tissues, including the breast, while retaining agonistic activity on receptors located in the nucleus. The low oestrogenicity of estetrol may potentially contribute to reduced thrombotic risk. Estetrol/drospirenone was an effective contraceptive in phase II and III clinical trials, with regular and predictable bleeding cycles maintained in the majority of women. Estetrol/drospirenone was generally well-tolerated with metrorrhagia reported as the most common treatment-related adverse event, which is consistent with other COCs. Cases of migraines with aura (or severe migraines), deep vein thrombosis, hyperkalaemia and depression were rarely reported during the phase III trials. Overall, estetrol/drospirenone is an effective and generally well-tolerated COC, with a potentially reduced risk of thrombosis.

In 2019, an estimated 44% of women aged 15–49 years worldwide used modern contraception methods, and in these women using modern methods, 18% used an oral contraceptive. Estetrol/drospirenone is a combined oral contraceptive (COC) which uses estetrol, a plant-synthesised oestrogen naturally produced by the human foetal liver during pregnancy, in combination with drospirenone, a well-known progestin. Combined, these hormones suppress ovulation, which constitutes their primary mode of action in preventing pregnancy. As estetrol has weaker oestrogen-related effects, it may potentially reduce the risk for blood clots. Estetrol/drospirenone was an effective contraceptive in clinical trials, and most women had regular and predictable bleeding cycles. Metrorrhagia (i.e. abnormal bleeding) was the most commonly reported treatment-related adverse effect; however, this is a common issue with hormonal contraceptives. Cases of severe migraine headaches, deep vein thrombosis, high potassium levels or depression were rarely reported during clinical trials. Estetrol/drospirenone is an effective oral contraceptive, which may offer a contraceptive option with a lower risk for blood clots. However, further research is required to confirm the reduced risk of clotting.

Variability in Contraceptive Clinical Trial Design and the Challenges in Making Comparisons Across Trials

Clinical trials of contraceptives have often differed in their study designs, making cross-trial comparisons difficult. This brief report outlines some of the technical design features that can vary from trial to trial. For example, the overall number of menstrual cycles in a study has substantial impact on the final efficacy determination; however, the rules related to qualifying cycles can differ based on the length of the study and the statistical analysis plan. In two commonly used methods of calculating efficacy, the Pearl Index and the time-to-event analysis, inclusion of fewer menstrual cycles results in higher calculated failure rates. Statistical analysis plans for contraceptive trials have sometimes excluded menstrual cycles because of an absence of documented vaginal intercourse and the concomitant use of another birth control method. Other design features that have varied between contraceptive trials relate to body mass index inclusion/exclusion criteria and the definition of "on-treatment" pregnancy. In addition, study designs of non-hormonal products can differ from those of hormonal products in their length and rules for qualifying cycles. The Draft Guidance for Hormonal Contraception, published in 2019 by the US Food and Drug Administration (FDA), will hopefully lead to more uniform trial design in the future, particularly for hormonal products. In the meantime, health care providers and patients should be aware of the nuances in trial design that make direct comparisons about relative efficacy challenging.

Pearl Index study with levonorgestrel-releasing intravaginal rings: using pharmacokinetic results to investigate treatment compliance as a potential contributor for contraceptive failure

STUDY QUESTION

What is the reason for insufficient contraceptive efficacy of levonorgestrel (LNG) delivered by intravaginal ring (IVR) releasing comparable amounts of LNG as approved progestogen-only pills (POPs)?

SUMMARY ANSWER

The pharmacokinetic (PK) evaluation in a subpopulation indicated that the steady-state concentration of plasma LNG was markedly lower in the participants in the USA compared to those in Japan suggesting non-compliance in the US participants which may explain a clearly higher Pearl Index (PI) in USA (8.2, unadjusted PI) compared to Japan (1.4, unadjusted PI).

WHAT IS KNOWN ALREADY

Contraceptive efficacy of LNG in POPs has been demonstrated following different routes of administration (e.g. orally, implants, intrauterine systems), and the PK is well-characterized including a target exposure needed for contraception. Exposure above this target concentration was reached in Phase 1 studies using IVR delivering 40 µg LNG per day.

STUDY DESIGN, SIZE, DURATION

The primary objective of this multicenter, open-label, single-arm study conducted in the USA and in Japan was to assess the contraceptive efficacy of an LNG-containing IVR during a planned treatment period of 1 year in healthy women 18-35 years of age. The study was planned to be conducted in 1600 participants (1300 in the USA, 300 in Japan). The study was prematurely terminated after approximately one-third of the planned exposure was reached due to a high number of pregnancies (28) in the US study population.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In total, 1471 participants were treated (1166 participants in the USA and 305 participants in Japan). The PI as a measure of contraceptive efficacy was calculated from the frequency of unintended pregnancies during treatment. LNG exposure in the systemic circulation was assessed during treatment in 136 participants (PK subgroups: 106 in the USA and 30 in Japan).

MAIN RESULTS AND THE ROLE OF CHANCE

The PK evaluation in the PK subgroups indicated that the steady-state concentration of plasma LNG after 6 months was markedly lower in the participants in the USA (geometric mean 91.2 ng/l) compared to those in Japan (263.8 ng/l). This PK finding cannot be explained by the regional differences in body weight observed between the PK subgroups, thus suggesting non-compliance in the US participants. In 15.7% of the samples collected in the USA and 3.5% samples in Japan, the LNG concentration at steady state was below the lower limit of quantification (10 ng/l), which is not expected with the required continuous use of the IVR documented in most of the eDiaries.

LIMITATIONS, REASONS FOR CAUTION

The planned duration of treatment was 12 months, but due to the premature termination of the study none of the participants completed the 12-month treatment. All data collected until the study termination were considered, but it is to be noted that the amount of missing data limits the conclusions that can be drawn from the data.

WIDER IMPLICATIONS OF THE FINDINGS

The results of this study triggered the termination of the project, because the objective to show sufficient contraceptive efficacy of the LNG IVR was not met. The choice of a user-dependent contraceptive method with an LNG dose that is not inhibiting ovulation is not advisable for women who may have compliance issues.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by Bayer AG and all authors are employees of Bayer AG.

TRIAL REGISTRATION NUMBER

NCT02403401.

A 1-year prospective, open-label, single-arm, multicenter, phase 3 trial of the contraceptive efficacy and safety of the oral progestin-only pill drospirenone 4 mg using a 24/4-day regimen

Objectives

To evaluate contraceptive effectiveness and safety of oral drospirenone 4 mg 24/4-day regimen in the United States.

Study design

We performed a prospective, single-arm, multicenter phase 3 trial in sexually active women for up to thirteen 28-day treatment cycles. Primary outcome was the Pearl index, calculated using confirmed on-drug pregnancies and evaluable cycles in nonbreastfeeding women aged ≤ 35 years. We assessed adverse events (AEs), including hyperkalemia and venous thromboembolism.

Results

Of 1006 women who received at least one dose of drospirenone, 352 women (35.0%) completed the trial and 654 (65.0%) women discontinued before trial end. Most participants (92.2%) were ≤ 35 years; one third had a body mass index (BMI) ≥ 30 kg/m². Among nonbreastfeeding women aged ≤ 35 years, there were 17 pregnancies (Pearl index: 4.0; 95% confidence interval [CI], 2.3-6.4; n = 953), of which three were unconfirmed and two were from sites excluded from the main analysis for major breaches of Food and Drug Administration regulations. The Pearl index was 2.9 (95% CI: 1.5-5.1) for confirmed pregnancies among 915 nonbreastfeeding women aged ≤ 35 years from sites with no protocol violations. Nearly all (95.4%) treatment-emergent AEs were mild or moderate in intensity. No cases of venous thromboembolism were reported. The frequency of hyperkalemia was 0.5%. Women with baseline systolic/diastolic blood pressure ≥ 130/85 mmHg had a mean reduction from baseline in blood pressure at exit visit (- 8.5/- 4.9 mmHg; n = 119). No other clinically relevant changes were observed. Participant satisfaction was high.

Conclusion

Drospirenone 4 mg 24/4 regimen provides effective contraception with a good safety/tolerability profile in a broad group of women, including overweight or obese women.

Implications

This new progestin-only contraceptive, drospirenone 4 mg in a 24/4 regimen, provides a contraceptive option for the majority of women regardless of blood pressure or BMI.

Efficacy of the 1-year (13-cycle) segesterone acetate and ethinylestradiol contraceptive vaginal system: results of two multicentre, open-label, single-arm, phase 3 trials

Background

A ring-shaped, contraceptive vaginal system designed to last 1 year (13 cycles) delivers an average of 0·15 mg segesterone acetate and 0·013 mg ethinylestradiol per day. We evaluated the efficacy of this contraceptive vaginal system and return to menses or pregnancy after use.

Methods

In two identically designed, multicentre, open-label, single-arm, phase 3 trials (one at 15 US academic and community sites and one at 12 US and international academic and community sites), participants followed a 21-days-in, 7-days-out segesterone acetate and ethinylestradiol contraceptive vaginal system schedule for up to 13 cycles. Participants were healthy, sexually active, non-pregnant, non-sterilised women aged 18–40 years. Women were cautioned that any removals during the 21 days of cyclic use should not exceed 2 h, and used daily paper diaries to record vaginal system use. Consistent with regulatory requirements for contraceptives, we calculated the Pearl Index for women aged 35 years and younger, excluding adjunctive contraception cycles, as the primary efficacy outcome measure. We also did intention-to-treat Kaplan-Meier life table analyses and followed up women who did not use hormonal contraceptives or desired pregnancy after study completion for 6 months for return to menses or pregnancy. The trials are registered with ClinicalTrials.gov, numbers NCT00455156 and NCT00263341.

Findings

Between Dec 19, 2006, and Oct 9, 2009, at the 15 US sites, and between Nov 1, 2006, and July 2, 2009, at the 12 US and international sites we enrolled 2278 women. Our overall efficacy analysis included 2265 participants (1130 in the US study and 1135 in the international study) and 1303 (57·5%) participants completed up to 13 cycles. The Pearl Index for the primary efficacy group was 2·98 (95% CI 2·13–4·06) per 100 woman-years, and was well within the range indicative of efficacy for a contraceptive under a woman's control. The Kaplan-Meier analysis revealed the contraceptive vaginal system was 97·5% effective, which provided further evidence of efficacy. Pregnancy occurrence was similar across cycles. All 290 follow-up participants reported return to menses or became pregnant (24 [63%] of 38 women who desired pregnancy) within 6 months.

Interpretation

The segesterone acetate and ethinylestradiol contraceptive vaginal system is an effective contraceptive for 13 consecutive cycles of use. This new product adds to the contraceptive method mix and the 1-year duration of use means that women do not need to return to the clinic or pharmacy for refills every few months.

Funding

Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health, the US Agency for International Development, and the WHO Reproductive Health Research Department.

Factors associated with nonadherence to instructions for using the Nestorone®/ethinyl estradiol contraceptive vaginal ring

OBJECTIVES

We sought to identify factors associated with nonadherence to instructions for using a novel contraceptive providing 1 year of protection.

STUDY DESIGN

Data from a multicountry Phase 3 trial of the Nestorone® (segesterone acetate)/ethinyl estradiol (NES/EE) contraceptive vaginal ring (CVR) were analyzed. Participants were instructed to use the CVR over 13 cycles and follow a 21/7 regimen. Their reports of CVR removals >2 h outside scheduled removal periods served as a proxy for nonadherence. We used multivariate logistic regression to determine factors associated with such use.

RESULTS

Of 905 participants, 120 (13%) reported CVR removals >2 h. Removals for washing [odds ratio (OR) 3.96, 95% confidence interval (CI) 2.50-6.27] or sexual intercourse (OR 3.19, 95% CI 2.03-4.99), and finding CVR insertion difficult (OR 2.80, 95% CI 1.36-5.80) were factors associated with removals >2 h. Lower educational attainment also predicted ring removal >2 h (OR 3.23, 95% CI 1.55-6.75). Women residing in Europe or Australia were less likely to remove the ring for >2 h compared with women in the United States (OR 0.44, 95% CI 0.24-0.83 and OR 0.13, 95% CI 0.02-0.98, respectively). Participants who reported removals >2 h were more likely to discontinue CVR use (OR 1.93, 95% CI 1.24-2.95), report dissatisfaction (OR 2.20, 95% CI 1.32-3.69) and become pregnant during the study (OR 4.07, 95% CI 1.58-10.50).

CONCLUSIONS

Removing the CVR for washing and removing it before intercourse are factors associated with nonadherence to ring use. These are important topics for counseling women who are considering or using vaginal rings, including the NES/EE CVR.

IMPLICATIONS

Findings from this study may be useful in guiding counseling for current and prospective vaginal ring users. Anticipatory guidance should focus on how the ring feels in the vagina and during sex. Asking about ring removals may help identify women who are at increased risk for having an unplanned pregnancy.

Male hormonal contraception: hope and promise

Family planning is a shared responsibility, but available male-directed contraceptive methods are either not easily reversible (vasectomy) or not sufficiently effective (condom). However, roughly 20% of couples using a contraceptive method worldwide, and up to 80% in some countries, still choose a male-directed method. Male hormonal contraception is highly effective, with perfect use failure rates of 0·6% (95% CI 0·3-1·1) if sperm concentrations of less than 1 million per mL are maintained. After cessation of male hormonal contraception, sperm output fully recovers in a predictable manner, resulting in pregnancies and livebirths. Spontaneous miscarriage and fetal malformation rates after recovery of sperm output overlap those in the general population. Short-term adverse events-acne, night sweats, increased weight, and altered mood and libido-are recognised, but are generally mild. Further optimisation of specific androgen-progestin regimens and phase 3 studies of lead combinations are still needed to successfully develop an approved male hormonal contraceptive and to identify long-term side-effects.

An update on new orally administered contraceptives for women

INTRODUCTION

The focus in contraception is shifting from oral contraceptives to more effective methods, such as implants and intrauterine devices. Generics are favored by third-party payors. As a result, potentially exciting developments in branded pills to increase safety or to reduce side effects may have gone unnoticed.

AREAS COVERED

This article reviews the features of each of the four new oral contraceptives that have been introduced in the United States and/or Europe in the last few years. The motivation for the development of each product is outlined as is its efficacy, safety, tolerability and the noncontraceptive applications that have been explored are described.

EXPERT OPINION

The hypothesis that using estradiol in place of ethinyl estradiol would reduce the risk of venous thromboembolism is still to be proven. However, the stronger progestogens used in these formulations may offer other tangible benefits for selected women. The new products for extended cycle pill use may have less impact. The flexible regimen can be adopted using any pill, but the approved product does provide convenience to patients. Cost will continue to be the determining factor in the acceptance of these new products, unless substantial health benefits can be conclusively proven.