The effect of laquinimod, a novel immuno-modulator in development to treat Huntington disease, on the pharmacokinetics of ethinylestradiol and levonorgestrel in healthy young women.

PURPOSE: Laquinimod is an orally dosed immuno-modulator currently under development for Huntington's disease (HD). Preclinical findings suggest potential teratogenicity of laquinimod, thus the reproductive ability of females with HD treated with laquinimod needs to be closely managed. Because combined oral contraceptives (COC) are often used in this context, the pharmacokinetics of COC containing ethinylestradiol (EE) and levonorgestrel (LNG) in combination with laquinimod (0.6 mg/day) was evaluated. METHODS: In this randomized, phase-1 single-center, double-blind, placebo-controlled, 2-way crossover drug-drug interaction (DDI) study in 48 healthy premenopausal women, COC were administered in a 28-day regimen of 21 days followed by 7 pill-free days for 4 cycles and laquinimod or placebo was administered for 28 days in cycle 1 and cycle 3 starting 7 days prior to COC administration. Blood samples for pharmacokinetic profiling of laquinimod, EE and LNG were collected on day 21 and day 22 of Cycles 1 and 3 pre-dose and multiple times post-dose. RESULTS: The ratio of geometric means and 90% confidence intervals for AUC0-24 and Cmax of EE and LNG with and without laquinimod were all within the bioequivalence range (80 to 125%). Laquinimod pharmacokinetics was consistent with those observed in previous studies. The adverse event profile was in line with the current knowledge on the safety profile of both drugs, with headache as the most frequently reported treatment-related adverse event. CONCLUSION: The combination of COC and laquinimod treatment was found to be safe, tolerable, and devoid of any noticeable pharmacokinetic interaction.

Phase II dose-finding study on ovulation inhibition and cycle control associated with the use of contraceptive vaginal rings containing 17ß-estradiol and the progestagens etonogestrel or nomegestrol acetate compared to NuvaRing.

PURPOSE: To identify at least one contraceptive vaginal ring that effectively inhibits ovulation and demonstrates cycle control that is non-inferior to NuvaRing® (Merck Sharp & Dohme B.V., The Netherlands) in terms of an unscheduled bleeding incidence, with a non-inferiority margin of 10%. METHODS: This was a randomised, active controlled, parallel group, multicentre, partially blinded trial in healthy women 18-35 years of age. Subjects received one of six contraceptive vaginal rings with an average daily release rate of 300 µg 17ß-estradiol (E2) and various rates of either etonogestrel (ENG; 75, 100, or 125 µg/day) or nomegestrol acetate (NOMAC; 500, 700, or 900 µg/day), or the active control NuvaRing® (ENG/ethinylestradiol 120/15 µg), for three 28-day cycles. RESULTS: Ovulation inhibition was observed in all groups as confirmed by absence of progesterone concentrations compatible with ovulation (>16 nmol/L) and absence of ultrasound evidence of ovulation. All investigational rings provided good cycle control, with the ENG-E2 125/300 µg/day group being associated with the best cycle control based on the numerically lowest incidence of unscheduled bleeding and absence of scheduled bleeding. Non-inferiority to NuvaRing® with respect to the incidence of unscheduled bleeding could not be concluded for any of the investigational ring groups. The safety profile was consistent with the known safety profile of combined estrogen/progestin contraceptives and similar across all groups. CONCLUSIONS: Contraceptive rings releasing 300 µg E2 and 75-125 µg/day of ENG or 500-900 µg/day of NOMAC provided adequate ovulation inhibition and cycle control and are generally well-tolerated. While non-inferiority to NuvaRing® was not met, among the investigational rings, the ENG-E2 125/300 ring provided the best cycle control.

Psychometric validation of the dysmenorrhea daily diary (DysDD): a patient-reported outcome for dysmenorrhea.

PURPOSE: The objective of this study was to evaluate the psychometric properties of the Dysmenorrhea Daily Diary (DysDD), an electronic patient-reported outcome, in a sample of 355 women with primary dysmenorrhea enrolled in a phase IIb, multicenter, randomized, partially blinded, placebo-controlled trial for treatment of dysmenorrhea. METHODS: Subjects completed the DysDD over three menstrual cycles, one pre-treatment baseline cycle and two treatment cycles. The DysDD was administered alongside the Menstrual Distress Questionnaire (MDQ), the Short-Form 36 Version 2.0 (SF-36v2), and a Global Assessment of Change (GAC). Item response distributions, test-retest reliability, concurrent and known groups validity, responsiveness, and minimally important difference (MID) were evaluated for the DysDD. RESULTS: As expected, item response distributions varied throughout the menstrual period for all items, with the response scales fully utilized. Within-cycle test-retest reliability was adequate (weighted kappa: 0.5-0.7), although between-cycle test-retest was poor (weighted kappa: 0.1-0.5), most likely due to the highly variable nature of dysmenorrhea between cycles rather than limitations of the measure. Correlations with the MDQ and SF-36v2 were low-moderate, but in the predicted direction, supporting concurrent validity. There were significant differences in DysDD scores across severity groups based on pain medication use. The DysDD was responsive to changes in patients' dysmenorrhea with significantly different changes in scores between change groups (p < 0.0001). MID analyses suggest changes on the DysDD 0-10 pelvic pain score of three points can be considered clinically meaningful. CONCLUSIONS: Overall, findings indicate that the DysDD has acceptable reliability and is a valid and responsive instrument for assessing dysmenorrhea.

Efficacy and safety of the contraceptive vaginal ring (NuvaRing) compared with a combined oral contraceptive in Chinese women: a 1-year randomised trial.

OBJECTIVES: The aim of the study was to assess the efficacy and tolerability of the monthly vaginal ring (NuvaRing; 15 µg ethinylestradiol [EE] and 120 µg etonogestrel per day) compared with a monophasic (21/7) combined oral contraceptive (COC) containing 30 µg EE and 3 mg drospirenone in healthy Chinese women aged 18-40 years. METHODS: This was a phase III, open-label, randomised multicentre trial conducted in China. Participants received NuvaRing or COC for 13 cycles (3 weeks of ring/pill treatment followed by a 1-week ring-free/pill-free period). Contraceptive efficacy was assessed by in-treatment pregnancies and expressed by the Pearl Index (PI; number of pregnancies/100 woman-years of use). Cycle control was assessed by unscheduled (breakthrough) and absence of scheduled (withdrawal) bleeding events. Safety and tolerability were assessed throughout the study. RESULTS: Participants were randomised either to the NuvaRing (n = 732) or to the COC (n = 214); 588 (82.4%) and 182 (78.4%) participants, respectively, completed the study. There were 10 in-treatment pregnancies in the NuvaRing group (PI 1.92; 95% confidence interval [CI] 0.92, 3.53) and five in the COC group (PI 3.12; 95% CI 1.01, 7.29). Breakthrough bleeding/spotting ranged from 18.6% (Cycle 1) to 4.2% (Cycle 11) for NuvaRing and from 21.6% (Cycle 1) to 7.9% (Cycle 11) for COC. Absence of withdrawal bleeding ranged from 8.6% (Cycle 1) to 3.0% (Cycle 11) for NuvaRing and from 14.6% (Cycle 1) to 6.4% (Cycle 5) for COC. For NuvaRing and COC, respectively, 26.6% and 25.0% of participants had treatment-related adverse events, and 7.0% and 9.1% discontinued the study as a result. CONCLUSIONS: Once-monthly NuvaRing is efficacious and safe for use in Chinese women.

Comparative analysis of the effects of nomegestrol acetate/17 ß-estradiol and drospirenone/ethinylestradiol on premenstrual and menstrual symptoms and dysmenorrhea.

OBJECTIVES: To compare premenstrual and menstrual symptoms in healthy women using nomegestrol acetate/17ß-estradiol (NOMAC/E2) and drospirenone/ethinylestradiol (DRSP/EE) via the Moos Menstrual Distress Questionnaire Form C (MDQ-C). METHODS: Women completed the MDQ-C at baseline and after completion of cycles 1, 3, 6 and 13, for the premenstrual (four days before most recent flow) and menstrual (most recent flow) phases in two randomized controlled trials. Treatment effects of NOMAC/E2 and DRSP/EE on the t-scores of eight MDQ-C symptom domains from 3522 women were examined, and the effects of both treatments on the score for cramps from 1779 women with moderate to severe cramps at baseline. Longitudinal data analysis methods were applied in both analyses. RESULTS: NOMAC/E2 users experienced a significant improvement in Pain, Water Retention, Negative Affect, Impaired Concentration and Behaviour Change domain scores in the menstrual phase compared with DRSP/EE users (p < 0.001 for all comparisons). However, Arousal (emotional and mental) scores worsened with NOMAC/E2 but not with DRSP/EE. Women with moderate to severe cramps experienced an improvement in the cramps score with NOMAC/E2 and DRSP/EE. CONCLUSIONS: NOMAC/E2 was effective in reducing most premenstrual and menstrual symptoms, and was associated with significantly greater improvements in many MDQ-C domain scores compared with DRSP/EE. ( ClinicalTrials.gov: NCT00413062 and NCT00511199).

Efficacy and tolerability of a monophasic combined oral contraceptive containing nomegestrol acetate and 17ß-oestradiol in a 24/4 regimen, in comparison to an oral contraceptive containing ethinylestradiol and drospirenone in a 21/7 regimen.

OBJECTIVES: The primary objective was to assess the efficacy, cycle control and tolerability of a monophasic combined oral contraceptive (COC) containing nomegestrol acetate (NOMAC) and 17ß-oestradiol (E2). Effects on acne were evaluated as a secondary objective. Results were compared to those of a COC containing drospirenone (DRSP) and ethinylestradiol (EE). METHODS: Women (aged 18-50 years) were randomised to receive NOMAC/E2 (2.5 mg/1.5 mg) in a 24/4-day regimen (n=1591) or DRSP/EE (3 mg/30 µg) in a 21/7-day regimen (n=535) for 13 cycles. RESULTS: Estimated Pearl Indices for NOMAC/E2 and DRSP/EE were 0.38 and 0.81 in women aged≤35 years and 0.31 and 0.66 for all women (18-50 years), respectively. Scheduled withdrawal bleedings were shorter and lighter among users of NOMAC/E2 and were sometimes absent altogether. Intracyclic bleeding/spotting was infrequent in both groups, and decreased over time. Type and frequency of adverse events were similar to those typically reported for COCs. CONCLUSIONS: These data show that NOMAC/E2 provides high contraceptive efficacy with acceptable cycle control as well as an overall adverse event profile similar to that of DRSP/EE.

Effects of a monophasic combined oral contraceptive containing nomegestrol acetate and 17 beta-oestradiol on ovarian function in comparison to a monophasic combined oral contraceptive containing drospirenone and ethinylestradiol.

OBJECTIVE: To compare the effects on ovarian activity of two oral contraceptives containing nomegestrol acetate (NOMAC)/17 beta-oestradiol (E2) or drospirenone (DRSP)/ethinylestradiol (EE). METHODS: In this open-label, randomised, six-cycle study, 32 subjects using NOMAC/E2 (2.5-1.5 mg; 24/4-day regimen) were compared to 16 subjects using DRSP/EE (3 mg-30 microg; 21/7-day regimen). Measurements included serum oestradiol, progesterone, follicle stimulating hormone (FSH) and luteinising hormone (LH), and ultrasonography of follicular diameter. RESULTS: No ovulations occurred during treatment. Progesterone was fully suppressed, with mean maximum values <2 nmol/l in both groups over all cycles. For NOMAC/E2, mean maximum follicular diameter decreased from 19.3 mm before treatment to between 6.9 and 8.2 mm during treatment, with no subject having a follicular diameter ≥15 mm. For DRSP/EE, a decrease from 19.6 to between 7.4 and 10.8 mm was observed, with two subjects (12.5%) having a maximum follicle diameter ≥15 mm. These findings were consistent with observed FSH reductions; full suppression of LH surges was observed in both groups. Post-treatment return of ovulation in both groups occurred on average 21 days after the last active tablet intake. CONCLUSIONS: NOMAC/E2 achieves consistent ovulation inhibition, with suppressive effects on the ovaries at least similar to those of DRSP/EE.

A phase 2b multicenter, randomized, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of vaginal rings containing nomegestrol acetate or etonogestrel and 17ß-estradiol in the treatment of women with primary dysmenorrhea.

OBJECTIVE: To evaluate the effect of investigational vaginal rings containing nomegestrol acetate (NOMAC) plus 17ß-estradiol (E2) or etonogestrel (ENG) plus E2 in women with moderate to severe primary dysmenorrhea. STUDY DESIGN: This was a Phase 2b randomized, placebo-controlled, multicenter, double-blind study. We randomized participants to one of five treatment groups: four hormonal rings and one placebo ring. The investigational vaginal rings released 300 µg of E2 daily along with 700 µg or 900 µg of NOMAC or 100 µg or 125 µg of ENG. Each participant received 2 identical rings and was to insert each for 21 days followed by a 7-day ring-free period. The primary endpoint, as assessed by a daily electronic diary (e-Diary), was the change in menstrual pain score from baseline to the second in-treatment withdrawal bleeding episode (Cycle 2). The pain score was the mean of the three highest scores for menstrual cramping pain (0-4 point scale) recorded from the day before menses to the third day of bleeding. The primary hypothesis was that at least one investigational vaginal ring would demonstrate a statistically significant larger reduction from baseline in pain score compared to placebo. Secondary endpoints included total mean impact score (which assessed the negative impact on work/school, physical activities, leisure/social activities) and the amount and days of rescue medication (ibuprofen) used. CLINICAL TRIAL REGISTRATION NUMBER: NCT01670656. RESULTS: We randomized 439 participants. The mean pain score decreased from baseline to Cycle 2 in all groups; the decrease in all four treatment groups compared to placebo was statistically significant (p-values ≤0.002). All treatment groups had greater reductions than placebo in ibuprofen intake and greater improvement in impact scores; these differences were statistically significant for both endpoints for the ENG-E2 100/300 µg/day group, while the other groups were not statistically significant for one or both endpoints. CONCLUSION: All four investigational rings produced a statistically significantly larger reduction from baseline in mean menstrual pain score compared to placebo while pain medication use decreased. IMPLICATIONS: This placebo-controlled study provides evidence that vaginal contraceptive rings containing NOMAC-E2 or ENG-E2 improve moderate to severe dysmenorrhea, across all of doses studied. This adds to the evidence that hormonal contraceptives are effective treatments for dysmenorrhea.

Can initial vaginal bleeding patterns in etonogestrel implant users predict subsequent bleeding in the first 2 years of use?

OBJECTIVES: To evaluate if a simple method for characterizing vaginal bleeding patterns in etonogestrel contraceptive implant users can predict subsequent patterns and bleeding-related discontinuation over the first 2 years of use. STUDY DESIGN: We reanalyzed phase 3 study bleeding data for non-breastfeeding participants from the United States, Europe, Russia and Chile during the first 2 years of implant use to characterize and correlate bleeding patterns. We used 90-day reference periods with period 1.1 starting at Day 29 and ending at Day 118. We dichotomized bleeding patterns as "favorable" (amenorrhea, infrequent bleeding and normal frequency bleeding without prolonged bleeding) or "unfavorable' (prolonged and/or frequent bleeding) and tracked user groups based on these bleeding patterns in reference period 1.1 through Year 1 and from Year 1 through Year 2, respectively. RESULTS: We evaluated data from 537 and 428 women with up to 1 and 2 years use, respectively. Of the 325 (60.5%) women with favorable bleeding in reference period 1.1, 275 (84.6%) reported favorable bleeding also in reference period 2, 197 (60.6%) reported favorable bleeding throughout Year 1, and favorable bleeding in 75-85% of reference periods in Year 2. Among 212 (39.5%) women with unfavorable bleeding in reference period 1.1, 118 (55.7%) continued with unfavorable bleeding in reference period 2, while about 40%-50% reported favorable patterns in RP 2, 3 and/or 4. Initial favorable bleeding resulted in lower discontinuation rates than initial unfavorable bleeding in years 1 (3.7% vs 12.7%, p≪.0001) and 2 (2.5% vs 16.5%, p≪.0001). CONCLUSION: Implant users with favorable bleeding in the first reference period are likely to continue with favorable bleeding over the next 2 years. Initial bleeding patterns predict overall continuation rates in years 1 and 2. Implications Statement When evaluating vaginal bleeding in any 90-day reference period over 2 years of etonogestrel implant use, approximately 80% of women with favorable and 40% with unfavorable bleeding patterns will have favorable bleeding in the next reference periods. These findings can facilitate counseling regarding bleeding for women using the etonogestrel implant.

Ovulation incidence with oral contraceptives: a literature review.

BACKGROUND AND METHODOLOGY: Combined oral contraceptives (COCs) provide reliable and convenient contraception, although contraindications and tolerability issues may limit their use in some women. Progestogen-only pills (POPs) may be more suitable for some women, however, traditional POPs do not have the same contraceptive efficacy as COCs. A literature search was performed in order to assess the incidence of ovulation with available COCs, traditional POPs and with a desogestrel POP [Cerazette, 75 microg desogestrel (DSG)]. The following databases were searched: MEDLINE, EMBASE, Biosis, Derwent Drug File, Current Contents and the in-house Organon database 'Docs' (which contains all published reports of Organon products). Searches used free-text terms [e.g. Contraceptive$ in combination with (Ovulat$ adj Rate$), (Ovar$ adj Activ$) or (Escap$ adj Ovulat$)] and were limited to the search criteria 'Human' and 'from 1979 onwards'. The searches included publications up to July 2008. RESULTS: Many of the studies were hampered by inadequate ovulation criteria; however, the overall incidence of ovulation determined by the reports uncovered in the literature search was 2.0% [95% confidence interval (CI) 1.1-3.3] with COCs containing 30-35 microg ethinylestradiol (EE), 1.1% (95% CI 0.60-2.0) with 15-20 microg EE COCs, 4.6% (95% CI 2.8-6.9) with phasic COCs, 1.25% (95% CI 0.03-6.8) with Cerazette and 42.6% (95% CI 33.4-52.2) with traditional POPs. CONCLUSIONS: The findings indicate that COCs and the desogestrel POP are equally effective in suppressing ovulation, whilst the traditional POP formulations are less effective.

Pooled analysis of two randomized, open-label studies comparing the effects of nomegestrol acetate/17ß-estradiol and drospirenone/ethinyl estradiol on bleeding patterns in healthy women.

OBJECTIVES: To obtain more precise and detailed information regarding the bleeding patterns of nomegestrol acetate (NOMAC)/17ß-estradiol (E2) and drospirenone/ethinyl estradiol (DRSP/EE) and to identify whether baseline demographic characteristics were associated with unscheduled bleeding, absent scheduled bleeding, or amenorrhea. STUDY DESIGN: This analysis pooled results from two pivotal open-label, randomized trials that compared bleeding patterns of NOMAC/E2 and DRSP/EE. In the two studies 4317 women aged 18-50 years from 24 countries across the Americas, Europe, and Asia underwent treatment. RESULTS: 2835 women taking NOMAC/E2 (2.5 mg/1.5 mg) in a 24/4-day regimen and 938 women taking DRSP/EE (3 mg/30 µg) in a 21/7-day regimen had at least 1 evaluable cycle for vaginal bleeding analyses. The frequency of absent scheduled bleeding was higher (p<.0001) for women using NOMAC/E2 than DRSP/EE across all 11 cycles (cycles 2-12), ranging between 17.6% and 31.6% and between 3.4% and 5.8%, respectively. For women who had absent scheduled bleeding in cycles 2, 3, or 4 the incidence of absent scheduled bleeding in subsequent cycles was high and ranged between approximately 50%-60% for NOMAC/E2 and approximately 40%-50% for DRSP/EE. Amenorrhea increased over time with both regimens, being higher with NOMAC/E2. Both absent scheduled bleeding and amenorrhea with NOMAC/E2 were more common in older women, overweight women, switchers, and smokers; unscheduled bleeding was more common in starters, but had no association with age, body mass index, and smoking. CONCLUSIONS: NOMAC/E2 is associated with a higher prevalence of absent scheduled bleeding compared with DRSP/EE. Absent scheduled bleeding and amenorrhea were associated with age, body weight, switching and smoking. Unscheduled bleeding was more common in starters. IMPLICATIONS: Information about the factors associated with bleeding patterns may help clinicians provide guidance to women considering use of the NOMAC/E2 oral contraceptive.

Maintenance of ovulation inhibition with the 75-microg desogestrel-only contraceptive pill (Cerazette) after scheduled 12-h delays in tablet intake.

BACKGROUND: In contrast to traditional progestagen-only pills (POPs), the desogestrel-only pill Cerazette consistently inhibits ovulation. This study was performed to test the hypothesis that desogestrel alone will keep inhibiting ovulation even when pills are taken 12 h late, indicating that delays in tablet intake of up to 12 h do not jeopardize contraceptive efficacy. METHODS: Women aged between 19 and 40 years with confirmed ovulation were admitted to this open-label pharmacodynamic study. They were treated with Cerazette for 56 days with three tablets to be taken 12 h late, having been randomized to a regimen with scheduled late tablets on Days 39, 42 and 49 (Group A) or on Days 11, 14 and 21 (Group B). The occurrence of ovulation during treatment was determined by measuring progesterone serum levels every 2 days. RESULTS: One of the 103 treated subjects ovulated during treatment. The ovulation incidence thus amounts to 1.0% (two-sided 95% confidence interval 0.02-5.29%). There was no apparent relationship between these ovulations and scheduled late tablets. The minimum time to first posttreatment ovulation was 7 days, whereas it took 17.2 days on average from last tablet intake until ovulation. CONCLUSIONS: Ovulation inhibition with Cerazette is maintained after 12-h delays in tablet intake and return of ovulation takes at least 7 days. These properties distinguish Cerazette from all other POPs.

Efficacy, safety, and tolerability of a monophasic oral contraceptive containing nomegestrol acetate and 17ß-estradiol: a randomized controlled trial.

OBJECTIVE: To estimate the efficacy, cycle control, tolerability, and safety of a monophasic combined oral contraceptive containing nomegestrol acetate and 17ß-estradiol (E2) in comparison with drospirenone and ethinyl E2. METHODS: In a randomized, open-label, comparative multicenter trial, healthy women (n=2,281; age 18-50 years) at risk for pregnancy and in need of contraception were allocated in a 3:1 ratio to receive nomegestrol acetate (2.5 mg) and 17ß-E2 (1.5 mg) in a 24-4-day regimen (investigational drug) or drospirenone (3.0 mg) and ethinyl E2 (30 micrograms) in a 21-7-day regimen (comparator) for 13 consecutive, 28-day cycles. The primary end point was the Pearl Index. RESULTS: The Pearl Indices for 18- to 35-year-old women in the investigational (n=1,375) and comparator (n=463) groups were 1.27 (95% confidence interval [CI] 0.66-2.22) and 1.89 (95% CI 0.69-4.11), respectively. Respective 1-year cumulative pregnancy rates were 1.22 (95% CI 0.69-2.16) and 1.82 (95% CI 0.81-4.05). By the end of the trial, shorter, lighter scheduled bleeding or an absence of scheduled bleeding occurred with greater frequency (32.9%) in the investigational group, whereas unscheduled bleeding or spotting episodes were low (16.2% and 15.0% in the investigational and comparator groups, respectively). Acne prevalence decreased from approximately 33% at baseline to 22% and 14% at cycle 13 in the respective groups. In the investigational group, the most frequently reported adverse events were acne (16.4%), weight gain (9.5%), and irregular withdrawal bleeding (9.1%). CONCLUSION: Nomegestrol acetate and 17ß-E2 were well tolerated and provided excellent contraceptive efficacy and acceptable cycle control. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov, www.clinicaltrials.gov, NCT00413062. LEVEL OF EVIDENCE: I.

The contraceptive efficacy of Implanon: a review of clinical trials and marketing experience.

OBJECTIVES: To evaluate the contraceptive efficacy of the etonogestrel-releasing implant Implanon as assessed in international studies and during nine years of marketing experience. METHODS: The analysis included 11 international studies and data collected during nine years of marketing experience (1998--2007). Seven of these studies were noncomparative; the four other studies included the 6-rod levonorgestrel implant system or an intrauterine device as a comparator. All studies except one were of at least two years in duration, and all had contraceptive efficacy as the objective. Market data were provided unsolicited to Organon, part of Schering Plough. RESULTS: The integrated efficacy analysis included 923 non-breastfeeding women who were exposed to the implant for 24,100 cycles. No in-treatment or pretreatment pregnancies were reported. Fifty posttreatment pregnancies were reported, six of which occurred within 14 days of implant removal, indicating that fertility had quickly returned. Over a nine-year marketing period an overall pregnancy rate of 0.049 per 100 implants sold (estimated Pearl Index = 0.031 based on all pregnancies reported) was calculated. When only counting contraceptive method failures the pregnancy rate amounts to 0.010 per 100 implants sold (estimated Pearl Index = 0.006). CONCLUSION: Implanon is a highly effective and quickly reversible subdermal method of long-acting hormonal contraception for women. Typical use of this implant achieves a contraceptive protection exceeding 99%.

The effects of Implanon on menstrual bleeding patterns.

OBJECTIVES: To evaluate an integrated analysis of bleeding patterns associated with use of the subdermal contraceptive implant Implanon (etonogestrel, Organon, part of Schering-Plough) and to provide physician guidance to optimize patient counselling. METHODS: Data from 11 clinical trials were reviewed (N = 923). Assessments included bleeding-spotting records, dysmenorrhoea, and patient-perceived reasons for discontinuation. Bleeding patterns were analysed via reference period (RP) analyses. RESULTS: Implanon use was associated with the following bleeding irregularities: amenorrhoea (22.2%) and infrequent (33.6%), frequent (6.7%), and/or prolonged bleeding (17.7%). In 75% of RPs, bleeding-spotting days were fewer than or comparable to those observed during the natural cycle, but they occurred at unpredictable intervals. The bleeding pattern experienced during the initial phase predicted future patterns for the majority of women. The group of women with favourable bleeding patterns during the first three months tended to continue with this pattern throughout the first two years of use, whereas the group with unfavourable initial patterns had at least a 50% chance that the pattern would improve. Only 11.3% of patients discontinued owing to bleeding irregularities, mainly because of prolonged flow and frequent irregular bleeding. Most women (77%) who had baseline dysmenorrhoea experienced complete resolution of symptoms. CONCLUSION: Implanon use is associated with an unpredictable bleeding pattern, which includes amenorrhoea and infrequent, frequent, and/or prolonged bleeding. The bleeding pattern experienced during the first three months is broadly predictive of future bleeding patterns for many women. Effective preinsertion counselling on the possible changes in bleeding patterns may improve continuation rates.