As endogenous estrogen production declines during menopause, the vagina and other estrogen-dependent tissues gradually undergo atrophic changes. Changes in cytology can occur with decreased estrogen levels, leading to increased basal and parabasal cells in relation to superficial cells. The loss of estrogen-dependent cellular maturation in the vagina can result in atrophic vaginitis, with symptoms of dryness, soreness, irritation, discharge, and dyspareunia. Additionally, the vaginal epithelium becomes more susceptible to infection and secondary inflammation. Estrogen therapy can counteract many of these changes and reduce associated complications.1,2 Although postmenopausal atrophic vaginitis is a common condition in elderly women, only a small percentage of those affected receive treatment with estrogens.3–5 In symptomatic women who have no other indications for systemic hormone replacement or prefer not to use systemic therapy, local vaginal treatment with estrogen is effective in reversing atrophic vaginal changes and relieving symptoms.6
The use of progestin however, to protect the endometrium from the effects of unopposed estrogen, is not indicated when vaginal atrophy is treated with local, low-dose estrogen.7 The Food and Drug Administration currently recommends that the lowest effective dose of estrogen (either alone or in combination with progestins) should be used for the shortest possible time period to balance the treatment goals with the risks for individual women.
A low-dose estrogen vaginal tablet that contains 25 mcg estradiol (E2) in a hydrophilic cellulose-based matrix has been shown to provide steady absorption in an atrophic vaginal vault, with absorption significantly reduced after maturation of the epithelium.8 In a study comparing 25 mcg and 10 mcg of these vaginal E2 tablets, administered once daily for 2 weeks followed by twice-weekly dosing for another 10 weeks, low absorption of E2, without systemic effects, was reported.9 The use of a vaginal tablet and applicator to deliver E2 to the vaginal epithelium allows administration of a consistent dose of estrogen to the epithelial tissue, reduces the potential for leakage that is often associated with vaginal creams and vagitories,10,11 and relieves atrophic vaginitis symptoms without the need for daily treatment.
This study evaluated and compared the efficacy of vaginal tablets containing 25 mcg E2 (Vagifem, Novo Nordisk Inc., Princeton, NJ), 10 mcg E2 or placebo during 12 weeks of therapy for vaginal atrophy in menopausal women. In an open-label extension, all participants converted to the use of 25 mcg E2 administered twice-weekly, and efficacy of therapy was monitored.
MATERIALS AND METHODS
This randomized, double-blind, placebo-controlled, parallel-group 12-week study was conducted at nine centers, followed by a 52 week open-label extension study at eight centers in the United States. During the 12-week study, the efficacy of 10 mcg and 25 mcg dose of E2 compared with placebo for the treatment of the symptoms associated with atrophic vaginitis was assessed. The primary objective of the 52 week open-label study was to provide additional data regarding extended use of the 25 mcg E2 dose. The studies were approved by the appropriate institutional review boards at each site, and written informed consent was obtained from each participant before the start of study procedures
Women aged 45 years or older with moderate-to-severe vaginal dryness and soreness were enrolled (N=230). All participants had serum E2 concentrations of 20 pg/mL or less, with 5% or less superficial vaginal cells. Participants were also required to be at least 12 months postmenopausal, with an endometrial thickness of 5 mm or less as determined by transvaginal ultrasonography.
Known or suspected history of breast carcinoma, hormone-dependent tumor, genital bleeding of unknown cause, acute thrombophlebitis or thromboembolic disorder associated with estrogen use, vaginal infection requiring treatment, allergy to the test drug or its constituents, or any serious disease or chronic condition that could interfere with study compliance were among the criteria for exclusion. The use of any investigational drug within the 30 days preceding screening, any homeopathic preparation within the 7 days preceding study drug initiation, and any exogenous corticosteroid or sex hormones within the 8 weeks preceding study drug initiation were prohibited. Inclusion in the 52-week extension study required completion of all 12 weeks of the randomized study and a second signed informed consent form.
Participants assignments were randomized using a 2:2:1 ratio to receive vaginal tablets that contained either 25 mcg E2, or 10 mcg E2, or placebo (90:90:45). A randomization code was generated and assigned in blocks of five. A sealed envelope with the randomization number and identity of the treatment for each participant was given to each investigator. Participants were always assigned the next available or lowest free randomization number. The 2:2:1 ratio was selected to minimize the number of participants exposed to placebo. This sample size would provide a 90% power in detecting a difference in change from baseline score of 0.5 between active treatment and placebo with an assumed standard deviation of 0.85 for the primary efficacy endpoints (change from baseline in composite score of vaginal dryness, soreness and irritation). To adjust for multiple treatment comparisons, a step-down procedure was applied to first compare 25 mcg E2 with placebo, and if found to be statistically significant at 0.05 level, to then compare 10 mcg E2 with placebo. For the open-label extension, the sample size was dependent on the number of patients willing to continue on 25 mcg E2, so no formal power calculations were performed.
All vaginal tablets were identical in appearance. The medications package prepared for each participant in the double-blind phase had an allocation number using a drug assignment list supplied by Novo Nordisk. Treatment instructions were to insert one vaginal tablet daily for 14 days, and subsequently, one tablet twice per week. The participants were also instructed to insert the tablets at the same time each day. Evaluations for efficacy and safety occurred at weeks 2, 4, 7, 12, and at weeks 13, 26, 39, 52 in the open-label extension.
The symptoms of atrophic vaginitis evaluated were vaginal dryness, soreness, irritation, discharge, and dyspareunia. However, vaginal discharge and dyspareunia were excluded from the composite vaginal symptom score because vaginal discharge was rated as none or mild by the majority of participants and dyspareunia was not indicated by every participant. Therefore, the primary efficacy endpoint was the change in the composite score of three vaginal symptoms (dryness, soreness, and irritation). Assessments of these three vaginal symptoms were conducted at baseline (week 0) and weeks 2, 4, 7, 12, and 52. The severity of each symptom was self-assessed and received a grade based on a four-point scale (0=none, 1=mild, 2=moderate, 3=severe). A composite score of these symptoms (mean of the individual symptom scores for dryness, soreness, and irritation) was then generated.
Additional efficacy assessments included grading of vaginal health (degree of epithelial integrity and thickness, vaginal secretions, color, and vaginal pH) and vaginal and urethral cytology. Gradings of vaginal health indicated the degree of epithelial atrophy (0=none, 1=mild, 2=moderate, 3=severe). As a component of the vaginal health assessment, vaginal pH was measured in intervals (pH less than 5, 5-5.49, 5.5–6.49, and more than 6.49). The composite score for vaginal health, assessed by the investigator, was defined as the mean of the individual vaginal health components, and only participants who had assessments for all five measures were included in the analysis of composite score.
Vaginal and urethral cell samples were analyzed by independent cytologists (Diagnostic Cytology Labs, Indianapolis, IN) to determine the percentages of parabasal, intermediate, and superficial cells. The vaginal and urethral maturation value was calculated according to the formula, maturation value=(0×% of parabasal cells)+(0.5×% of intermediate cells)+(1.0×% of superficial cells). Endometrial biopsies in nonhysterectomized patients were performed at week 12.
An analysis of variance model was used to make comparisons of the treatment effect on changes from baseline in composite scores of vaginal symptoms. Analyses of vaginal health composite score and individual measures, vaginal cytology cells, and maturation value, were also done using an analysis of variance model.
The objectives of the open-label extension study were to evaluate long-term treatment with vaginal E2 tablets on the endometrium in patients with estrogen deficiency-derived vaginitis through assessment of biopsy results and adverse events. The treatment regimen consisted of one tablet administered intravaginally, twice weekly.
Endometrial biopsies in nonhysterectomized patients were performed at week 52. Evaluations were made by two independent pathologists who were masked to treatment group and each other’s interpretation. Discordant results were adjudicated by a third pathologist to determine the final evaluation, and in cases where all three readings were discordant, a blinded reevaluation was conducted by the third pathologist. When all pathologists disagreed or when one pathologist gave two differing opinions, the most severe interpretations were assigned as the final biopsy results. In addition, a sample of evaluations that were in agreement was sent to the third pathologist for quality control purposes.
The secondary objective was to evaluate whether efficacy measures could be sustained over 52 weeks of treatment (relief of vaginal symptoms, grading of vaginal health, and maturation of vaginal and urethral cells). After 12 weeks of treatment, all participants were treated with 25 mcg E2 and were evaluated at weeks 13, 26, 39, and 52.
Routine laboratory assessments were done by central laboratories and included hematology (hemoglobin, hematocrit, and red blood cell and white blood cell counts measured at screening and the final visit of both the randomized and extension studies), blood chemistry (sodium, potassium, chloride, total bilirubin, alkaline phosphatase, lactic dehydrogenase, γ-glutamyltransferase, blood urea nitrogen, aspartate transaminase, alanine transaminase, creatinine, uric acid, phosphorus, calcium, glucose, total protein, total cholesterol, and triglycerides measured at screening and the final visit of both the randomized and extension studies), and urinalysis (measured at screening and final visit of the randomized study and every visit of the extension study). Test results were categorized as normal, high, or low based on laboratory reference ranges. Analysis of blood specimens for serum hormone levels (serum E2, estrone, and estrone sulfate) was conducted by Quest Diagnostics (Madison, NJ). Physical examination findings including vital signs (temperature, supine systolic and diastolic blood pressures, and pulse rate), body weight, and general examination findings were recorded by the investigators.
The primary efficacy variables, vaginal symptoms (dryness, soreness, irritation, discharge, and dyspareunia), and the main secondary endpoints (grading of vaginal health and maturation of vaginal and urethral mucosa) were recorded at weeks 13, 26, 39, and 52. Ratings for these variables were obtained using the same ascending scales, and composite scores were obtained, as described for the randomized study above. For all efficacy variables, statistical analyses were carried out based on an intent-to-treat population, which included all patients who received at least one dose of study medication. Paired t tests were used to test the change from baseline composite scores within each treatment group. Vaginal cell maturation and urethral cell data were recorded and analyzed by paired t test for within-group differences in change from baseline values.
The enrollment period for this trial was from 1994 to 1996. Of the nine centers recruiting participants, one center did not participate in the extension phase. The nonparticipating center recruited only one participant, who did not want to continue on in the extension phase. For the 12-week randomized study, a total of 91 women received 25 mcg E2, 92 received 10 mcg E2, and 47 received placebo (Fig. 1). Demographic and baseline characteristics were similar across treatment groups, with the exception of a slightly higher percentage of white participants in the 25 mcg E2 group (Table 1). Nine participants (9.9%) in the 25 mcg E2 group, 18 (19.6%) in the 10 mcg E2 group, and eight participants (17.0%) in the placebo group did not complete the 12-week randomized study (Fig. 1).
Of the 102 women who continued to the 52-week extension study, 38 were from the former 25 mcg E2 group, 46 were from the former 10 mcg E2 group, and 18 were from the former placebo group (Fig. 1). Aside from race, there were no notable differences between the groups for any demographic or baseline variable. Twice as many women with histories of cardiovascular disease from the 25 mcg and 10 mcg E2 groups, as compared with the placebo group, continued in the extension study. Eleven participants (28.9%) in the former 25 mcg E2 group, 11 (23.9%) in the former 10 mcg E2 group, and four participants (22.2%) in the former placebo group did not complete the 52-week extension study.
Vaginal symptom composite score profiles between weeks 0 and 12 are shown in Figure 2. At week 0, the vaginal symptom composite scores measured approximately 1.9 in each treatment group. At weeks 2, 7, and 12, vaginal symptom composite scores were significantly lower than the corresponding baseline values for each treatment group (P<.001). In the 25 mcg E2 and 10 mcg E2 groups, vaginal symptom composite scores continued to decrease after week 0, and at week 12 measured approximately 0.45 and 0.56, respectively. In contrast, in the placebo group, vaginal symptom scores remained nearly constant after week 2 and were approximately 1.1. At weeks 7 and 12, the decreases from baseline observed in the 25 mcg E2 group were significantly larger than those observed in the placebo group (P<.005 at week 7 and P<.05 at week 12). Decreases were also observed in the 10 mcg E2 group at weeks 7 (P<.05) and 12 (P=.07). Values for the 25 mcg E2 group were not significantly lower than those for 10 mcg E2 at any time point from week 0 to week 12. All patients switched to 25 mcg E2 in the extension study and all three groups showed statistically significant reductions (P<.001) from baseline (of the randomized study) to week 52 in the change in composite score over time: –1.4 for the former 25 mcg E2 group, –1.6 for the former 10 mcg E2 group, and –1.7 for the former placebo group.
Vaginal health composite scores at week 0 measured approximately 1.7 in each treatment group, and at weeks 2, 7, and 12, the scores were significantly lower than the corresponding baseline values for each treatment group (Fig. 3). In comparison with placebo treatment, the mean vaginal health composite scores observed in the 25 mcg E2 and 10 mcg E2 groups at weeks 2, 7, and 12 were significantly lower. Only at week 7 was the mean score for the 25 mcg E2 group significantly lower than for the 10 mcg E2 group. After switching to 25 mcg E2 in the extension study, the former placebo group showed a decrease in vaginal health composite score from week 12 to week 52. As compared with baseline (of the randomized study), at week 52, the change in mean composite score was –1.29 for the former 25 mcg E2 group, –1.41 for the former 10 mcg E2 group, and –1.48 for the former placebo group.
At baseline (week 0), 11.1% of those in the 25 mcg E2 group had vaginal pH less than 5.0, as compared with 11.2% in the 10 mcg E2 group and 13.0% in the placebo group. After 12 weeks of treatment, the proportion of participants with pH less than 5 were 51%, 39%, and 21% in the 25 mcg E2, 10 mcg E2, and placebo group respectively. At week 52, after switching to 25 mcg E2, the proportion of participants who now had pH less than 5 were 35%, 32%, and 36% in the former 25 mcg E2, former 10 mcg E2, and former placebo groups, respectively. That is, over the course of the extension study, mean pH scores were maintained in the active treatment groups, and decreased in the placebo group.
The vaginal cytology results showed significant increases at weeks 2 and 7 in the percentage of superficial cells for participants in the 25 mcg E2 group as compared with placebo. Throughout the extension study, 25 mcg E2 treatment resulted in maintenance of significantly higher percentages of superficial cells as compared with week 0. Percentages of superficial and intermediate cells were reflected in higher maturation values for the 25 mcg E2 group than placebo at weeks 2 and 7 (Table 2). Maturation values for the 10 mcg E2 group were significantly higher than for placebo at week 2 (P<.001) and were not significantly different from the improved values for the 25 mcg E2 group at any time point. After switching to 25 mcg E2, maturation values were increased significantly at week 52 as compared with week 0: by 11.6 for the former 25 mcg E2 group, 12.9 for the former 10 mcg E2 group, and 18.6 for the former placebo group.
Urethral cytology results for time points up to week 12 also showed either significant increases or trends toward increases in the percentage of superficial cells for participants in the 25 mcg and 10 mcg E2 group compared with baseline. The analyses of individual cell types showed a shift over time from immature parabasal cells to the more mature intermediate and superficial cells. Throughout the extension study, 25 mcg E2 treatment resulted in maintenance of significantly higher percentages of superficial cells as compared with week 0. At week 52 of the extension study, the percentages of superficial cells were increased by 14.0 in the former 25 mcg E2 group, 11.5 in the former 10 mcg E2 group, and 13.5 in the former placebo group, as compared with baseline of the randomized study.
At week 12 of the randomized study, endometrial biopsies were performed on 86 women (25 mcg E2, 32 participants; 10 mcg E2, 33 participants, placebo, 21 participants). Of these, 14 participants had insufficient tissue samples (25 mcg E2, 3 participants; 10 mcg E2, 8 participants; and placebo, 3 participants). Among those with biopsies that yielded sufficient tissue, one participant in the 25 mcg E2 group showed simple hyperplasia without atypia in the 12-week study. However, there was no pretreatment biopsy for comparison. This one incident of hyperplasia may reflect the epidemiologic incidence in this patient population; however, a causal relationship to the study drug could not be excluded. Endometrial biopsy evaluation was the primary objective of the extension study and was performed for 42 participants with intact uteri who finished the 52-week treatment, 15 in the former 25 mcg E2 group, 18 in the former 10 mcg E2 group, and 9 in the former placebo group. Of the endometrial biopsies that were classifiable, results in all the three study groups were normal (no hyperplasias or malignancies). Within the normal category one patient had a proliferative endometrium. Twelve of those biopsied had insufficient tissue for a histologic classification (6 in the former 25 mcg E2 group and 6 in the former 10 mcg E2 group), which is not unusual for postmenopausal women. Additionally, transvaginal ultrasound was conducted for all women with insufficient tissue obtained during endometrial biopsy. All endometrial thickness results were 5 mm or less. Adverse events were unremarkable for this patient population and therapy type, with no apparent trends in dose-related or treatment effects. There were seven treatment-emergent adverse events that occurred at a frequency rate of 5% or less: headache (placebo, 6%; 10 mcg E2, 3%; 25 mcg E2, 9%); back pain (placebo, 6%; 10 mcg E2, 0%; 25 mcg E2, 7%); abdominal pain (placebo, 4%; 10 mcg; E2, 5%; 25 mcg E2, 7%); moniliasis genital (placebo, 2%; 10 mcg E2, 0%; 25 mcg E2, 5%); upper respiratory infection (placebo, 4%; 10 mcg E2, 7%; 25 mcg E2, 5%); vaginitis (placebo, 6%; 10 mcg E2,4%; 25 mcg E2, 3%) and vaginal discomfort (placebo, 0%; 10 mcg E2, 5%; 25 mcg E2, 3%).
There was only one death and three serious adverse events reported for this study. One placebo patient died of an accidental drowning 19 days after discontinuing study medication. Three additional patients experienced serious adverse events other than death: one placebo patient with an ovarian cyst and two 25 mcg E2 patients, with renal clear-cell carcinoma and a basal cell carcinoma of the skin. None of the three other serious events nor the death was considered related to study treatments.
No abnormal shifts in gynecologic examination results were reported for any of the three groups for breast, external genitalia, vagina, cervix, uterus, or ovaries. Sampling for determination of hormone levels was performed once at each of the clinical visits, and the times since the last dosing of study drug varied. In the randomized study, baseline E2 levels were 10.3±21.5, 13.2±34.4, and 11.8±17.59 pg/mL in the 25 mcg E2, 10 mcg E2, and placebo groups, respectively. At week 52, changes from week 0 E2 levels were –0.4 pg/mL for the 25 mcg E2 group, +1.5 pg/mL for the 10 mcg E2 group, and +1.2 pg/mL for the placebo group. Estrone levels of 25.1±12.7 pg/mL, 25.2±21.0 pg/mL, and 24.9±12.5 pg/mL were observed at baseline of the randomized study in the 25 mcg E2, 10 mcg E2, and placebo groups; at the end of week 52, the levels were 27.8±12.8 pg/mL, 27.2±11.3 pg/mL, and 22.7±4.8 pg/mL, respectively. The estrone sulfate levels at randomized baseline were 341±359 pg/mL in the 25 mcg E2 group, 336±615 pg/mL in the 10 mcg E2 group, and 328±268 pg/mL in the placebo group; at the end of week 52 the levels were 321±180 pg/mL, 372±266 pg/mL, and 261±124 pg/mL, respectively.
Clinical laboratory tests for blood chemistry, hematology and urinalysis were done at the screening visit (Week –4) and at week 12 of the randomized study and week 52 of the extension. Statistically significant (P<.05) but clinically small mean changes from Week –4 to Week 52 were observed in the former 25 mcg E2 group for bilirubin, alkaline phosphatase, γ-glutamyl transpeptidase, total protein, and total cholesterol, in the former 10 mcg E2 group for creatinine, glucose, and total protein, and in the former placebo group for creatinine. No clinically significant shifts were identified for any of the blood chemistry variables over this time period. At week 52, the only statistically significant (P<.05) mean changes in hematology variables were in hemoglobin and red blood cell values in the 25 mcg E2 group as compared with Week –4. Statistically significant mean changes at week 12 were noted in reduced white blood cell count in the 25 mcg E2 group and in hemoglobin values in the 10 mcg E2 and placebo groups. None of the mean changes were clinically relevant. Urinalysis results were reviewed by a clinician, and changes in pH, ketones, proteins, and glucose variables at week 52 were considered clinically noteworthy.
The majority of physical examination findings were characterized as normal, and abnormal findings were deemed not inconsistent with what would be expected in a population of this age group that was not being treated with E2. There were no clinically significant findings related to study drugs. Measurements of blood pressure, respiratory rate, pulse rate, temperature, and weight remained relatively unchanged from week 0 to week 52.
An estimated 50% or more of postmenopausal women will experience some form of urogenital discomfort such as atrophic vaginitis.1,12 Local therapies, such as the estradiol vaginal tablets used in this study, have been developed to relieve the symptoms of atrophic vaginitis without producing significant systemic absorption. Previous data suggested that 10 mcg dosage (once daily for 3 weeks followed by twice weekly administration for 9 weeks) leads to improvement or cure of 82% of symptoms, whereas plasma levels remained within a 3–10 pg/mL range.13 Similar improvement has been seen in our study with 10 mcg E2 vaginal tablets. The improvement was mainly observed in the vaginal health composite score, which was an objective assessment conducted by study investigators. Subjective symptoms evaluated by women were also improved compared with placebo, but in our study this improvement was only statistically significant (P<.05) at week 7.
Treatment with 25 mcg and 10 mcg E2 tablets resulted in greater improvement in vaginal symptoms (as assessed by the participants) and urogenital health (as assessed by the investigators) than treatment with placebo. At each time point after baseline, improvements in the vaginal health composite scores were significantly greater in the 25 mcg and 10 mcg E2 group than in the placebo group (P<.001). At each time point after 2 weeks of treatment, improvements in the vaginal symptom composite scores were also significantly greater (P<.05) with 25 mcg E2.
With respect to vaginal pH, the results indicate a positive effect of the E2 vaginal tablets on estrogenization of the vaginal epithelium.14 This trend toward normalization of pH could potentially result in less frequent infections and reduction in irritative symptoms.
The lower portions of the vaginal and urinary tracts have the same embryologic origin. As such, atrophic vaginitis is often accompanied by similar atrophic changes in the urinary tract that may manifest as dysuria, stress incontinence, and urinary tract infections.4,15,16 Determination of the proportions of the cellular components indicate a statistically significant increase in the percentage of superficial cells present in the vaginal and urethral epithelium after 52 weeks of treatment, compared with baseline values. The implication of these results is that estrogen therapy could potentially reduce epithelial friability and thinning and thus the frequency and severity of some of the symptoms associated with vaginal and urethral atrophy.
Results with 10 mcg E2 showed significant improvement in vaginal health score, but were not entirely consistent with those for 25 mcg E2 in all analyses. Although increased maturation value with 10 mcg E2 over placebo only reached statistical significance at week 2; the increase compared with baseline was nevertheless significant at all time points after week 0. Likewise, in terms of mean score for three vaginal symptoms, 10 mcg E2 resulted in significant improvements at all time points after week 0 as compared with baseline, but were only statistically significantly better than placebo at week 7. Nevertheless, there were no significant differences between the 25 mcg E2 and 10 mcg E2 groups in terms of improvements in maturation value or mean composite score of vaginal symptoms at any time point after week 0.
In this study, after 12 weeks of treatment, one participant in the 25 mcg E2 group had simple hyperplasia without atypia. However, no prestudy endometrial biopsy was performed to assess the endometrial cavity before treatment. Among other studies that have used the same 25 mcg E2 tablets, a 24-week study involving 80 women found a single incidence of proliferative endometrium,11 whereas among 31 women who completed a 52-week study receiving twice-weekly doses of 25 mcg E2 tablets, two women had weakly proliferative endometrium.17
Vaginal tablets with 25 mcg and 10 mcg E2 provided relief of vaginal symptoms, improved urogenital atrophy, decreased vaginal pH, and increased maturation of the vaginal and urethral epithelium. Those improvements were greater with 25 mcg than with 10 mcg E2. Both doses were effective in the treatment of atrophic vaginitis.