Lunelle monthly contraceptive injection (medroxyprogesterone acetate and estradiol cypionate injectable suspension): effects of body weight and injection sites on pharmacokinetics

Effect of a single dose of a combination injectable contraceptive for treatment of bothersome uterine bleeding in contraceptive implant(s) users: A randomized double-blind placebo-controlled trial

OBJECTIVES

This study aimed to determine the proportion of participants whose uterine bleeding/spotting was interrupted for at least 7 days during the month after they received a combined hormonal injection. We also evaluated bleeding at 21 days and 12 weeks after the injection.

STUDY DESIGN

We conducted a randomized, double-blind, placebo-controlled trial in 46 contraceptive implant users who presented with bothersome uterine bleeding/spotting. A single dose of a combination injectable contraceptive or placebo was administered intramuscularly at enrollment.

RESULTS

The proportions of participants whose uterine bleeding/spotting was interrupted for at least 7 days the month after they received a combined hormonal injection were higher in the combination injectable contraception group than in the placebo group (87% vs 48%, p = 0.005). Participants who reported that they were bleeding free at 21 days after treatment were 52% and 35% in the combination injectable contraception group and placebo group, respectively (p = 0.24). At 12 weeks posttreatment, 17% of participants in the combination injectable contraception group and 4% in the placebo group reported cessation of bleeding with no recurrence (p = 0.34). The median days until the first bleeding interruption was shorter in the combination injectable contraception group compared with the placebo group (1 [interquartile range, 1-2] vs 8 [interquartile range, 1-28], p = 0.007).

CONCLUSIONS

The combination injectable contraception interrupted bothersome uterine bleeding/spotting in contraceptive implant(s) users compared with placebo. However, this effect was limited only within the month when the treatment was administered.

IMPLICATIONS

Bothersome uterine bleeding/spotting is a common side effect leading to contraceptive implant(s) discontinuation. In implant users experiencing these symptoms with no estrogen contraindications, a combined injectable contraception appears to rapidly improve bleeding for the duration of injectable exposure (1 month).

Pharmacokinetics of Long-Acting Aqueous Nano-/Microsuspensions After Intramuscular Administration in Different Animal Species and Humans-a Review

Formulating aqueous suspensions is an attractive strategy to incorporate poorly water-soluble drugs, where the drug release can be tailored to maintain desired release profiles of several weeks to months after parenteral (i.e., intramuscular or subcutaneous) administration. A sustained drug release can be desirable to combat chronic diseases by overcoming pill fatigue of a daily oral intake, hence, improving patient compliance. Although the marketed aqueous suspensions for intramuscular injection efficiently relieve the daily pill burden in chronic diseases, the exact drug release mechanisms remain to be fully unraveled. The in vivo drug release and subsequent absorption to the systemic circulation are influenced by a plethora of variables, resulting in a complex in vivo behavior of aqueous suspensions after intramuscular administration. A better understanding of the factors influencing the in vivo performance of aqueous suspensions could advance their drug development. An overview of the potential influential variables on the drug release after intramuscular injection of aqueous suspensions is provided with, where possible, available pharmacokinetic parameters in humans or other species derived from literature, patents, and clinical trials. These variables can be categorized into drug substance and formulation properties, administration site properties, and the host response towards drug particles. Based on the findings, the most critical factors are particle size, dose level, stabilizing excipient, drug lipophilicity, gender, body mass index, and host response.

Variability and quantification of serum medroxyprogesterone acetate levels

Quantification of serum progestin levels in clinical contraceptive studies is now routinely performed to understand progestin pharmacokinetics and to correct for unreliable self-reporting of contraceptive use by study participants. Many such studies are focussed on the three-monthly progestin-only intramuscular (IM) injectable contraceptive depot medroxyprogesterone acetate (DMPA-IM). Methods commonly used to measure serum MPA levels include liquid chromatography coupled to mass spectrometry (LC/MS) and radioimmunoassay (RIA); however, RIA methods have not been used in recent years. We review the available literature and find that these methods vary widely in terms of use of organic solvent extraction, use of derivitization and choice of organic solvent and chromatography columns. There is a lack of standardization of LC/MS methodology, including a lack of detailed extraction protocols. Limited evidence suggests that RIA, without organic solvent extraction, likely over-estimates progestin levels. Maximum MPA concentrations in the first two weeks post-injection show wide inter-individual and inter-study variation, regardless of quantification method used. Standardization of quantification methods and sampling time post-injection is required to improve interpretation of clinical data, in particular the side effects arising at different times depending on the pharmacokinetic profile unique to injectable contraceptives.

Pharmacokinetics, metabolism and serum concentrations of progestins used in contraception

Many different forms of hormonal contraception are used by millions of women worldwide. These contraceptives differ in the dose and type of synthetic progestogenic compound (progestin) used, as well as the route of administration and whether or not they contain estrogenic compounds. There is an increasing awareness that different forms of contraception and different progestins have different side-effect profiles, in particular their cardiovascular effects, effects on reproductive cancers and susceptibility to infectious diseases. There is a need to develop new methods to suit different needs and with minimal risks, especially in under-resourced areas. This requires a better understanding of the pharmacokinetics, metabolism, serum and tissue concentrations of progestins used in contraception as well as the biological activities of progestins and their metabolites via steroid receptors. Here we review the current knowledge on these topics and identify the research gaps. We show that there is a paucity of research on most of these topics for most progestins. We find that major impediments to clear conclusions on these topics include a lack of standardized methodologies, comparisons between non-parallel clinical studies and variability of data on serum concentrations between and within studies. The latter is most likely due, at least in part, to differences in intrinsic characteristics of participants. The review highlights the importance of insight on these topics in order to provide the best contraceptive options to women with minimal risks.

Quantification of estradiol cypionate in plasma by liquid chromatography coupled with tandem mass spectrometry: Application in a pharmacokinetic study in healthy female volunteers

The combination of medroxyprogesterone acetate 25 mg + estradiol cypionate 5 mg is a highly effective, monthly injectable contraceptive. For the first time, this study presents the development and validation of a sensitive method for estradiol cypionate analysis in human plasma by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Aliquots (500 μL) of plasma were extracted with ethyl ether (100%) and derivatized with dansyl chloride. Its separation was performed on a Jones Chromatography Genesis C8 column and the quantification was performed with a mass spectrometer equipped with an electrospray interface operating in negative ion mode. The run time was 6 min and the calibration curve was linear over the range of 0.005-0.15 ng/mL. The method was applied to evaluate the pharmacokinetics of estradiol cypionate in plasma collected up to 1008 h (42 days) after a single intramuscular administration of 25 mg/mL medroxyprogesterone acetate +5 mg/mL estradiol cypionate to healthy female volunteers (n = 12). The estradiol cypionate maximum plasma concentration (C_max) was 0.14 ± 0.08 ng/mL reached at 16.83 ± 21.07 h and the area under the plasma concentration versus time curve (AUC_0-last) was 14.07 ± 6.32 ng.h/mL. Elimination half-life (t_½), apparent volume of distribution (Vd/F), apparent clearance (CL/F) and mean residence time (MRT) were 89.65 ± 76.04 h, 28038 ± 9636 L, 49.02 ± 10.62 L/h and 576.05 ± 238.32 h, respectively, showing that the estradiol cypionate release from the administration site was prolonged and there was no drug accumulation.

Effectiveness of progestin-based therapy for morbidly obese women with complex atypical hyperplasia

OBJECTIVE

While progestins can effectively treat women with complex atypical hyperplasia (CAH), the impact of body habitus on treatment outcome is not well studied. We examine the association between body mass index (BMI) and progestin treatment outcomes.

METHODS

We conducted a retrospective cohort study of patients diagnosed with hyperplasia between 2003 and 2011. Demographics, past medical history, BMI, hormonal therapy, and histologic treatment response were abstracted. Patients with CAH who received progestin therapy were examined, and rates of regression were assessed.

RESULTS

Of 623 patients identified, 117 had CAH and satisfied the inclusion criteria. Median age was 34, and nearly, two-thirds (64%) were nulliparous. Mean BMI was 40.2, and 81% were obese (BMI 30-39.9: 36%, BMI ≥ 40: 45%). 103 patients (88%) received systemic progestin therapy and 14 patients (12%) received levonorgestrel-releasing intrauterine devices (LNG-IUS). 47 patients (40%) had a complete response to progestin-based therapy. BMI had no effect on the rate of complete response. The proportions of CAH patients with complete regression after hormonal therapy were BMI < 30: 39%, 30-39.9: 40%, and ≥ 40: 36% (P = 0.73). Women treated with LNG-IUS displayed higher rates of complete regression than those receiving systemic therapy (62% versus 38%, P = 0.096), and those with class III obesity were more likely than non-obese patients to receive LNG-IUS although neither reached statistical significance (< 40: 6.7% versus ≥ 40: 17%, P = 0.09).

CONCLUSION

In this morbidly obese population, response to progestin therapy was generally low; body habitus did not impact treatment outcome for CAH, but local therapy may be more effective than systemic therapy.

Permeation measurement of gestodene for some biodegradable materials using Franz diffusion cells

Biodegradable poly(d,l-lactide) (PDLLA), Poly(trimethylene carbonate) (PTMC), polycaprolactone (PCL), poly(caprolactone-co-d,l-lactide) (PCDLLA) and poly(trimethylene carbonate-co-caprolactone) (PTCL) are recently used for clinical drug delivery system such as subcutaneous contraceptive implant capsule due to their biodegradable properties that they could possess long-term stable performance in vivo without removal, however their permeation rate is unknown. In the work, biodegradable material membranes were prepared by solvent evaporation using chloroform, and commercial silicone rubber membrane served as a control. Gestodene was used as a model drug. Gestodene has high biologic progestational activity which allows for high contraceptive reliability at very low-dose levels. The permeation rate of gestodene for several biodegradable materials was evaluated. In vitro diffusion studies were done using Franz diffusion cells with a diffusion area of 1.33 cm². Phosphate buffer solution (PBS, pH 7.4), 10% methanol solution and distilled water were taken in donor and receiver chambers at temperature of 37 °C respectively. The in vitro experiments were conducted over a period of 24 h during which samples were collected at regular intervals. The withdrawn samples were appropriately diluted and measured on UV–vis spectrophotometer at 247 nm. Conclusion data from our study showed that permeation rate of PCDLLA with CL ratio more than 70% could be more excellent than commercial silicone rubber membrane. They may be suitable as a candidate carrier for gestodene subcutaneous contraceptive implants in contraceptive fields.

Medroxyprogesterone acetate and estradiol cypionate injectable suspension (Cyclofem) monthly contraceptive injection: steady-state pharmacokinetics

BACKGROUND

Cyclofem is a combined injectable contraceptive, containing medroxyprogesterone acetate (MPA) and estradiol cypionate. The objective was to characterize the steady-state pharmacokinetics (PK) using tandem liquid chromatography/mass spectrometry and compare these data to a previous PK study of this formulation in US women.

STUDY DESIGN

Fifteen ovulatory, surgically sterile women received three Cyclofem injections, once every 28 days, with serum PK measurements on 23 separate days. Trough levels of estradiol and MPA were obtained on Days 1, 29 and 57, prior to each of the three injections. Steady-state concentrations of MPA and estradiol were assessed during the third treatment month on Days 58, 60, 62, 64, 67, 69, 71, 75, 78 and 85. MPA and serum progesterone levels were measured during the follow-up phase to assess MPA clearance (Days 92, 99, 106, 113, 120, 127, 134 and 141) and return of ovulation (Days 103, 106, 131 and 134).

RESULTS

In the steady state, mean serum MPA concentrations peaked at 1.31 ng/mL at 4.1 days. Mean estradiol levels peaked at 254 pg/mL by 3.3 days. Ovulation was suppressed for at least 77 days post third injection in all but one woman.

CONCLUSIONS

Once monthly injections of Cyclofem resulted in contraceptive levels of MPA without accumulation of hormones, consistent with a previous US study.

Ovarian activity in obese and nonobese women treated with three transdermal contraceptive patches delivering three different doses of ethinyl estradiol and levonorgestrel

BACKGROUND

The effect of obesity on ovarian follicular suppression in women using low-estrogen dose contraceptive patches has not been determined.

STUDY DESIGN

A Phase II, parallel-group, multicenter, three-cycle study evaluated three patches containing different ethinyl estradiol (EE) and levonorgestrel (LNG) doses. Serum levels of EE, LNG, sex hormone-binding globulin and progesterone were compared in 41 obese [body mass index (BMI) ≥30] and 75 nonobese (BMI <30) women.

RESULTS

Suppression of ovulation during the luteal phase was dose dependent, with the highest dose (AG200-15) preventing progesterone increases in all women (cycles 2-3). In the follicular phase, the lowest-dose patch had the highest rate of increased progesterone in nonobese subjects. Progesterone levels ≥3.0 ng/mL in the follicular phase were more common in obese than nonobese women.

CONCLUSIONS

AG200-15 suppresses ovulation in obese and nonobese women. All three patches found increased progesterone in the follicular phase, albeit more in obese versus nonobese women.

Carbamazepine coadministration with an oral contraceptive: effects on steroid pharmacokinetics, ovulation, and bleeding

PURPOSE

Antiepileptic drugs (AEDs) are widely used in reproductive-age women. The AED carbamazepine (CBZ) induces the hepatic cytochrome P450 system, thereby accelerating hormone metabolism. We sought to assess the pharmacodynamic effects of CBZ on breakthrough bleeding and ovulation during oral contraceptive (OC) use.

METHODS

A double-blind, randomized, crossover study of healthy women ages 18-35 years. Participants took an OC containing 20 μg ethinyl estradiol (EE) and 100 μg levonorgestrel (LNG) for 4 months. Concurrently, participants took 600 mg CBZ or a matching placebo for 2 months each, administered in random order. During the second month of CBZ or placebo, we measured EE and LNG levels 12 times over 24 h, ovarian follicular diameters with eight biweekly vaginal ultrasounds, weekly progesterone levels, and bleeding (using a diary).

KEY FINDINGS

We enrolled 25 women; 10 completed the study. Five women discontinued because of reversible CBZ side effects. Mean area under the curve (AUC) measurements were lower during CBZ use compared to placebo for EE (1,778 vs. 986 pg*h/ml, p < 0.001) and LNG (24.8 vs. 13.8 pg*h/ml, p = 0.04). Ovulation occurred in 5 of 10 CBZ cycles compared to 1 of 10 placebo cycles (p = 0.06). Three or more days of breakthrough bleeding occurred during 8 of the 10 CBZ cycles compared to 2 of the 10 placebo cycles (p = 0.07).

SIGNIFICANCE

A commonly used dose of CBZ decreased levels of contraceptive steroids, increased breakthrough bleeding, and permitted ovulation during use of a low-dose OC. Women treated with CBZ are not adequately protected from pregnancy by low-dose OCs.

Pharmacokinetics of a combined oral contraceptive in obese and normal-weight women

BACKGROUND

This study was conducted to compare oral contraceptive (OC) pharmacokinetics (PK) in normal-weight [body mass index (BMI) 19.0-24.9] and obese (BMI 30.0-39.9) women.

STUDY DESIGN

During the third week of the third cycle of OC use, we admitted 15 normal-weight and 15 obese women for collection of 12 venous specimens over 24 h. Using radioimmunoassay techniques, we measured levels of ethinyl estradiol (EE) and levonorgestrel (LNG). During the same cycle, women underwent twice-weekly sonography to assess ovarian follicular development and blood draws to measure endogenous estradiol (E2) and progesterone levels.

RESULTS

Obese women had a lower area under the curve (AUC; 1077.2 vs. 1413.7 pg*h/mL) and lower maximum values (85.7 vs. 129.5 pg/mL) for EE than normal-weight women (p=.04 and <0.01, respectively); EE trough levels were similar between BMI groups. The similar, but smaller, differences in their LNG levels for AUC and maximum values (C(max)) were not statistically significant. While peak values differed somewhat, the LNG trough levels were similar for obese and normal-weight women (2.6 and 2.5 ng/mL, respectively). Women with greater EE AUC had smaller follicular diameters (p=.05) and lower E2 levels (p=.04). While follicular diameters tended to be larger among obese women, these differences were not statistically significant.

CONCLUSION

OC hormone peak levels are lower among obese women compared to normal-weight women, but their trough levels are similar. In this small study, the observed PK differences did not translate into more ovarian follicular activity among obese OC users.

Medroxyprogesterone acetate antagonizes the effects of estrogen treatment on social and sexual behavior in female macaques

Medroxyprogesterone acetate (MPA) commonly is used in contraception and hormone replacement therapy. However, little is known about its effects within the central nervous system. Using ovariectomized pigtail macaques (Macaca nemestrina), we evaluated the potential for MPA to antagonize estradiol (E2) effects on female sociosexual behavior. Subjects (n = 6) were treated sequentially with placebo, E2 alone, E2 + progesterone (P4), and E2 + MPA. The order of treatments was balanced among subjects, and equimolar quantities of P4 and MPA were administered. During each treatment period, female sexual initiation rates, anxiety-related behavior, and aggression were recorded. Treatment with E2 alone induced a substantial rise in female sexual initiation rates. Although concurrent P4 treatment failed to significantly inhibit sexual behavior, MPA treatment markedly antagonized E2's effects. Neither the E2-only nor the E2 + P4 treatment had an impact on aggression rates, but the E2 + MPA treatment induced a significant rise in this behavior. Both MPA and P4 counteracted the effect of E2 on measures of anxiety. These findings suggest that MPA antagonizes certain behavioral effects of E2 that may be beneficial to women, and that it does so more profoundly or in ways that endogenous P4 does not. The marked increase in aggression seen during MPA treatment suggests that production of negative affect may be a particularly serious side effect of MPA.

New Hormonal Contraceptives: A Comprehensive Review of the Literature

Over 16 million women in the United States take oral hormonal contraceptives, yet approximately 5% experience an unintended pregnancy during the first year of use. Compliance with the regimen is important in maintaining cycle control and preventing pregnancy. New hormonal contraceptive agents, norelgestromin-ethinyl estradiol patch, etonogestrel-ethinyl estradiol vaginal ring, and medroxyprogesterone-estradiol cypionate injection, were designed to increase compliance and decrease adverse effects while maintaining efficacy. Each one has potential advantages for women seeking alternatives to traditional oral contraceptives or for those who have trouble remembering to take a daily pill. Each agent also may have its own disadvantages, including application site reactions, need for monthly injections, and device-related events; however, all have similar efficacy and adverse-effect profiles compared with current oral hormonal contraceptives.

New contraceptive methods: update 2003

The decline in adolescent pregnancy rates noted in the 1990s has been attributed to more teenagers choosing abstinence, the availability of long-acting contraceptive options, and the increased use of condoms. Many adolescents remain at risk of unplanned pregnancy, however, because of method failure, inconsistent or incorrect use, or discontinuation of a method without choosing another method. Practitioners who care for adolescents and young women have access to several new methods in 2003. Recent additions include a contraceptive transdermal patch, a hormone-releasing intravaginal ring, new formulations of pills, and a new intrauterine device. Additionally, the World Health Organization has updated its guidelines to provide the practitioner with evidence-based recommendations to assist in selecting the most appropriate contraceptive method for each patient.

Contraceptive Efficacy and Patient Acceptance of Lunelle

PURPOSE

To review the efficacy, safety, and patient acceptance of the Lunelle monthly contraceptive injection and to raise awareness of this new contraceptive in the United States.

DATA SOURCES

Worldwide scientific literature, reports of clinical trials, and manufacturers' product information and guidelines.

CONCLUSIONS

Lunelle is a combined hormonal method with a safety/tolerability profile comparable to that of oral contraceptives (OC) and a high efficacy rate and provides a rapid return of fertility after discontinuation. Moreover, Lunelle was well accepted in a large clinical trial, with satisfaction levels similar to those of new-start OC users.

IMPLICATIONS FOR PRACTICE

Oral contraceptives are the most popular hormonal birth control method in the United States; however, typical use is associated with higher failure rates than those observed with perfect use because of poor compliance. Poor compliance has been attributed in part to the need for daily administration. A new contraceptive method that does not require daily administration and is readily reversible may be suitable for many women, resulting in better overall efficacy.

Injectable contraception. New and existing options

DMPA and MPA/E2C contraception offer women safe, effective, convenient, and reversible birth control choices. The use of DMPA, a 3-month injectable, is characteristically associated with amenorrhea. Lactating women and women in whom contraceptive doses of estrogen are contraindicated can use this progestin-only birth control method. Return of fertility can be delayed in women discontinuing DMPA to become pregnant. In some cases, the use of DMPA also confers important noncontraceptive and therapeutic benefits. A monthly estrogen/progestin injectable contraceptive, MPA/E2C should appeal to women who are concerned about daily pill taking, who prefer regular cycles to amenorrhea, and who find monthly injections acceptable and accessible. As is true for oral contraceptives, MPA/E2C represents an appropriate choice for women who prefer a rapidly reversible contraceptive. Currently, the proposed contraindications for MPA/E2C parallel those for combined oral contraceptives. As MPA/E2C contraception becomes available for American women, clinicians will learn how to best include this new method among the array of contraceptive choices. By individualizing contraceptive selection, counseling, and management approaches based on the relevant behavioral and medical considerations reviewed herein, clinicians can maximize their patients' success with injectable contraceptives. The more innovative that clinicians, family planning agencies, and insurers are in facilitating access to care (including reinjections), the more women will be able to avail themselves of safe, effective, and reversible methods of contraception. In addition to the physician's office or health clinic, other sites at which women might receive contraceptive injections include employee health clinics, college health clinics, or perhaps the pharmacy where the prescription is filled. Self-administration may become an appropriate option for some users of injectable contraception.

Lunelle monthly contraceptive injection (medroxyprogesterone acetate and estradiol cypionate injectable suspension): assessment of return of ovulation after three monthly injections in surgically sterile women

The pharmacodynamic effects of medroxyprogesterone acetate (MPA) and estradiol cypionate (E2C) (MPA/E2C) (Lunelle Monthly Contraceptive Injection) on ovarian function were assessed through changes in serum progesterone concentrations. The data described here were obtained simultaneously with pharmacokinetic data presented in another article in this issue. Sixteen surgically sterile women with regular menstrual cycles were studied for one control cycle, three consecutive treatment months, and 3-5 months of follow-up. Suppression, followed by resumption of ovulation (the dynamic end point), was assessed by serum progesterone levels. Return of ovulation was presumptive based on progesterone concentrations > or = 4.7 ng/mL, as ultrasound was not used to determine the follicular/ovulatory status of these subjects. Luteal-like serum progesterone peaks were observed in all 16 women before drug administration, confirming the presence of ovulatory cycles. After the third monthly injection of MPA/E2C, progesterone concentrations were measured until demonstration of ovulation. Two women discontinued and three were lost to follow-up before this objective was achieved. Serum progesterone levels and, consequently, ovulation were suppressed beyond the entire dosing interval, indicated by the absence of any luteal-like progesterone peaks (serum progesterone concentrations did not exceed 1 ng/mL). The first normal ovulatory cycle, based on progesterone concentrations > or = 4.7 ng/mL, was observed in 11 women between days 63 and 112 after the third injection. Select medroxyprogesterone acetate parameters (i.e., area under the curve and minimum concentration) were correlated with return of ovulation. The correlation coefficients (r) were 0.757 and 0.492 for area under the curve and minimum concentration, respectively, indicating that return of ovulation is dependent, in part, on area under the curve and on the magnitude of the serum MPA trough level. In general, the higher the minimum concentration levels, the longer the time to return of ovulation. In conclusion, the return of ovulation, as confirmed by serum progesterone concentrations > or = 4.7 ng/mL, was observed as early as 63 days after the third and final monthly intramuscular injection of MPA/E2C, suggesting that consistent suppression of the hypothalamic-pituitary-ovarian axis is reversible after discontinuation of dosing.

Comparative safety, efficacy, and cycle control of Lunelle monthly contraceptive injection (medroxyprogesterone acetate and estradiol cypionate injectable suspension) and Ortho-Novum 7/7/7 oral contraceptive (norethindrone/ethinyl estradiol triphasic). Lunelle Study Group

An open-label, nonrandomized, parallel, controlled study compared the efficacy, safety, and cycle control of a new monthly injectable contraceptive containing 25 mg of medroxyprogesterone acetate (MPA) and 5 mg of estradiol cypionate (E2C) (MPA/E2C) (Lunelle Monthly Contraceptive Injection) with that of a norethindrone 0.5, 0.75, 1.0 mg/0.035 mg ethinyl estradiol (NET/EE) triphasic oral contraceptive (Ortho-Novum 7/7/7). At study enrollment, women chose either the injections or the oral contraceptive. A higher proportion of women in the NET/EE group (65.1%) than in the MPA/E2C group (48.7%) had used hormonal contraception during the month before the study (p < 0.01). Overall, 55.5% (434/782) of MPA/E2C users and 67.6% (217/321) of NET/EE users completed the 60-week trial. One-year contraceptive efficacy (13 cycles of 28 days) for MPA/E2C and NET/EE was based on 8008 and 3434 woman-cycles of use, respectively. During the first year, one pregnancy occurred in an NET/EE user for a life table rate of 0.3; no pregnancies occurred in users of MPA/E2C. One additional pregnancy in the NET/EE group occurred during the 15th treatment cycle. After the first treatment cycle, women in both groups experienced regular menses, with an average cycle length of 28 days in MPA/E2C users and 27 days in NET/EE users. Although MPA/E2C users were more likely to experience bleeding irregularities, only 2.5% (19/775) cited metrorrhagia as a reason for discontinuing treatment. The adverse events reported in both treatment groups are consistent with those expected with the use of combined hormonal contraceptives. Overall, the results of this first Phase III US clinical trial of MPA/E2C confirm this method's high contraceptive efficacy and safety, as shown in previous studies by the World Health Organization. These results suggest that a monthly combination injectable would represent a welcome new contraceptive option for women in the US.

Lunelle monthly contraceptive injection (medroxyprogesterone acetate and estradiol cypionate injectable suspension): steady-state pharmacokinetics of MPA and E2 in surgically sterile women

The steady-state pharmacokinetics and pharmacodynamics of medroxyprogesterone acetate (MPA) and estradiol (E2, released from E2C by esterase enzymes) were characterized after administration to surgically sterile women. This report describes the pharmacokinetics of this multiple-dose and open-labeled study (pharmacodynamics are reported in a subsequent article in this issue). Women with regular menstrual cycles were studied for one control cycle, 3 consecutive treatment months, and 3-5 months of follow-up. Blood samples were drawn before each monthly dose and at specified time points after the third monthly injection. A total of 16 women were enrolled, 14 of whom completed the study. These 14 women (13 white, one black) ranged in age from 28 to 43.4 years, in body weight from 47.6 to 68.9 kg, and in height from 150 to 175 cm. Mean serum MPA concentrations peaked in the first week after administration of MPA/E2C (Lunelle Monthly Contraceptive Injection). The mean MPA Cmax and AUC0-t(last) were 1.25 ng/mL and 32.13 ng.day/mL, respectively. Serum MPA concentrations declined with a mean terminal half-life of 14.7 days, indicating that absorption from the injection site is prolonged after administration of MPA/E2C. The time for MPA concentrations to fall below the lower limit of quantitation (i.e., < 10 pg/mL) after the third injection ranged from 63 to 84 days. The average MPA trough (Cmin' day 28) concentrations for the three consecutive monthly injections ranged from 0.44 to 0.47 pg/mL, indicating that steady-state conditions were achieved after the first injection. The MPA Cmin values were well above threshold levels required to suppress ovulation throughout the injection interval. Absorption of E2 from the injection site was also prolonged after injection of MPA/E2C. Mean concentrations of E2 peaked at approximately 2 days after the third injection, and the average Cmax was 247 pg/mL. Serum E2 levels declined with a terminal half-life of approximately 8 days; E2 levels returned to baseline (typically, approximately 100 pg/mL) by 14 days after each injection. The average trough (Cmin' day 28) levels for E2 ranged from 40 to 55 pg/mL. The results of this study demonstrate that steady-state conditions are achieved after the first injection of MPA/E2C; no further MPA or E2 accumulation occurs beyond the first injection. Furthermore, the E2 peak observed after injection of MPA/E2C is similar to the nontreated preovulatory E2 range and returns to baseline levels by approximately 14 days after injection.