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Original Article |
Division of Endocrinology, Departments of Medicine (I.T.G.G., R.S.S., B.C., R.G., C.W.) and Pediatrics (N.B.), and Department of Obstetrics and Gynecology (A.L.N.), Harbor-University of California at Los Angeles Medical Center and Research and Education Institute, Torrance, California 90509
Address all correspondence and requests for reprints to: Christina Wang, M.D., General Clinical Research Center, Box 16, 1000 West Carson Street, Torrance, California 90502. E-mail: . wang{at}gcrc.rei.edu
Abstract
Recent studies demonstrate that combinations of androgens and progestagens are highly effective in the suppression of spermatogenesis in normal volunteers. To test whether progestagen and androgen delivery systems designed to produce steady serum levels will be as effective as other androgen plus progestagen combinations, we compared Norplant II and testosterone (T) transdermal patch to T patch alone on the suppression of spermatogenesis in normal men. Thirty-nine healthy male volunteers (age, 20–45 yr) were randomly assigned to one of two groups. Group 1 (n = 19) received two transdermal T patches daily (Testoderm TTS, each patch designed to deliver about 5 mg/d T) alone, and group 2 (n = 20) received combined Norplant II [Jadelle, four capsules delivering 
160 µg/d levonorgestrel (LNG)] plus T patch. Neither of these regimens were very effective, with suppression of spermatogenesis to severe oligozoospermia occurring in less than 60% of subjects. We then expanded the study to include two more groups to determine whether T patch or Norplant II was the main factor causing the inadequate suppression of spermatogenesis. Another 29 subjects were randomized to one of two groups. Group 3 (n = 15) received oral LNG (125 µg/d) plus T patch, and group 4 (n = 14) received Norplant II plus T enanthate (TE) injection (100 mg/wk im). After a pretreatment phase of 4 wk, all subjects received treatment for 24 wk, followed by a recovery period of 12–24 wk. Steady-state serum LNG levels (800–1200 pmol/liter) were achieved from wk 3–24 after Norplant II insertion and decreased rapidly after the removal of the implants at wk 24. Trough serum LNG levels after oral LNG administration were at a comparable range (940–1300 pmol/liter). Azoospermia was achieved in 24%, 35%, 33%, and 93%, and severe oligozoospermia (<1 x 106/ml) developed in 24%, 60%, 42%, and 100% of the subjects in groups 1, 2, 3, and 4, respectively, during treatment phase. All subjects in the Norplant II plus TE groups had persistent sperm concentrations less than 3 x 106/ml from wk 12 until the end of treatment. Concomitant with the marked suppression of spermatogenesis in the Norplant II plus TE group, serum FSH and LH levels were most decreased in this group compared with all other groups. In the T patch-only group, serum SHBG was not suppressed, and total serum T was higher than baseline levels. In the other three groups administered progestagens, serum SHBGs were significantly suppressed, and serum total T remained similar to baseline levels. Serum free T levels were not changed in any group. Except for a suppression of serum high-density lipoprotein cholesterol, there was no significant change in weight, hematocrit, clinical chemistry, or prostate-specific antigen levels in any of the treatment groups.
Although more efficacious than T patch alone, Norplant II or oral LNG plus T patch was not as effective in suppressing spermatogenesis to severe oligo- or azoospermia as in previous reports using oral LNG plus TE. This relative lesser efficacy occurred despite the achievement of serum LNG levels by Norplant II that were equivalent to those reported after administration of oral LNG. Substituting the transdermal T delivery system with TE injections resulted in very effective suppression of sperm output. The difference in spermatogenesis suppression of these combined regimens is likely due to less T delivered by the transdermal patch compared with the TE weekly injections. We conclude that Norplant II implants plus TE 100 mg/wk were very efficient in suppressing spermatogenesis to a level acceptable for contraceptive efficacy. This study demonstrates that the dose or route of administration of androgens is critical for sperm suppression in combined androgen-progestagen regimens for hormonal male contraception.
THE RESULTS OF multicenter clinical trials supported by the World Health Organization (WHO)/Contraceptive Research and Development (CONRAD) program have led to a renewed and energized interest in steroid base contraception for men (1, 2). In these studies, weekly im injections of testosterone enanthate (TE) in supraphysiological doses (200 mg/wk) resulting in serum T concentrations at or above the upper limit of the normal range induced azoospermia in 60–70% and oligozoospermia (<3 x 106/ml) in 98% of healthy men. These studies also confirmed that the achievement of persistent azoo- or oligozoospermia (<3 x 106/ml) resulted in acceptable contraceptive efficacy. Although quite effective as a contraceptive, weekly T injections would not be an acceptable method for most men.
To circumvent the requirement of supraphysiological doses of androgens, several progestagens and lower dose androgen combinations have been reported to be efficacious in the suppression of spermatogenesis (3, 4). On the basis of previously reported studies using levonorgestrel (LNG) as the progestagen (5, 6), Bebb et al. (7) showed that administration of LNG 500 µg orally daily combined with a lower dose TE 100 mg im weekly induced oligozoospermia (<3 x 106/ml) in over 94% of normal men compared with only 61% in subjects administered the same dose of T alone. They demonstrated that the combination of androgen and progestagen not only resulted in more suppression of gonadotropins and spermatogenesis but also a more rapid onset of action compared with androgen alone. Reducing the oral dose of LNG to 250 µg and 125 µg daily combined with TE injections resulted in similar effectiveness in suppression of circulating gonadotropins and spermatogenesis as LNG 500 µg/d while causing less weight gain and high-density lipoprotein (HDL) cholesterol suppression (8). Similar results were obtained when LNG was substituted with desogestrel (9, 10). The enhancing effect of progestagens to androgens was also demonstrated with the addition of depot-medroxyprogesterone injections to suboptimal dose of T implants for the suppression of spermatogenesis (11). A more recent study reported the additive effect of yet another progestagen (norethisterone enanthate) to T undecanoate (TU), both administered as im injections every 6 wk, resulted in azoospermia in 13 of 14 subjects in the combination group vs. 7 of 14 in the TU-alone group (12).
On the basis of the previous reports, we hypothesized that the administration of both androgens and progestagens using delivery systems that will provide relatively stable serum levels will be very effective in the suppression of spermatogenesis. We also considered the possibility that depot or transdermal preparations of androgen and progestagen combinations might result in less adverse effects than combinations of an oral or injectable progestagen and an injectable androgen.
To test the constant delivery system concept, we used Norplant II (LNG implants, Jadelle) to provide steady serum levels of LNG and daily transdermal T (Testoderm TTS) patches to attain physiological serum levels of T throughout the day. The primary objective of our study was to compare the effectiveness of steady serum levels of LNG plus androgen using Norplant II and transdermal T patch vs. transdermal T patch alone on the suppression of spermatogenesis. The secondary objectives were to characterize the pharmacokinetics of LNG delivered by Norplant II in normal men and to determine whether Norplant II will modify the effects of T on libido, mood, serum lipids, red cell parameters, and prostate disease markers. Because the initial results (see Results) showed inadequate suppression of spermatogenesis in both the Norplant II plus T patch and T patch alone groups, we then expanded the study to include two more treatment groups to determine whether T patch or Norplant II was the main factor causing the inadequate suppression of spermatogenesis. The additional two groups used the combination of transdermal T patch with oral LNG and Norplant II with TE injections at dosages that were used in prior published studies (7, 8). The results of these studies provided insights into optimization of drug delivery methods for male contraception.
Subjects and Methods
Subjects
Sixty-eight normal, healthy male volunteers between the ages of 18 and 50 yr were recruited through radio, newspaper, and bulletin boards advertisements. The subjects had no significant medical history and a normal physical examination. They had normal baseline hematology, blood chemistry, urinalysis, and fasting lipid profiles and three consecutive normal semen analyses at 2-wk intervals (sperm count, >20 x 106/ml; motility, >50%; and oval forms, >15%). The different ethnic groups were not represented equally in all treatment groups (Table 1
). Ethnic differences in responses were not tested statistically because the numbers in the nonwhite groups were too small to provide sufficient power for reliable analyses.
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Study design and medications
After a pretreatment period of 4 wk, subjects were initially randomized into one of two groups. Group 1 (n = 19) applied T transdermal patches alone. Placebo Norplant II was not used or justified because this would require surgical procedures for insertion as well as removal. Group 2 (n = 20) received transdermal T patches plus Norplant II, two systems, i.e. four capsules for 24 wk. The subsequent 29 subjects were randomized into two additional groups. Group 3 (n = 15) received oral LNG (125 µg /d) plus T patches. Group 4 (n = 14) received Norplant II, two systems plus TE injections (100 mg/wk).
The nonscrotal transdermal T patches (Testoderm TTS) were a gift from Alza Corp. (Mountain View, CA) obtained through Linda Atkinson, Ph.D. Each patch is 60 cm2 and is designed to deliver 5 mg/d T. Two transdermal patches (delivering 10 mg/d T) were applied daily to the upper or lower back, shoulders, upper arms, or buttocks depending on the subjects’ preferences. The Norplant II system (Jadelle, Leiras Pharmaceuticals, Turku, Finland) was provided by Harold Nash, Ph.D., from the Population Council (New York, NY). Each Norplant II system consists of two capsules. Each capsule is a 43-mm rod releasing 36–49 µg LNG/implant per day from a cured homogeneous mixture of LNG (about 75 mg per capsule) and a polydiniethyl siloxane elastomer covered by a thin-walled silicone rubber tubing. Four capsules (two systems) were implanted and removed by one of the investigators (A.N.) who has extensive experience with the Norplant systems. The capsules were implanted in the sc tissue of the inner upper third of the arm under local anesthesia at Harbor-University of California Los Angeles (UCLA) Medical Center General Clinical Research Center (GCRC). At the end of 24 wk of treatment, Norplant II capsules were removed under local anesthesia. LNG was obtained from Wyeth-Ayerst Laboratories, Inc. (Philadelphia, PA), through Michael Gast, M.D. The oral LNG was formulated into capsules at the University of Washington (Seattle, WA), through Alvin Matsumoto, M.D. Each capsule contained 125 µg LNG. Subjects took one capsule of LNG orally daily. TE 200 mg/ml in 5-ml vials distributed by Bio-Technology General Corp. (Delatestryl, Iselin, NJ) was obtained through our hospital pharmacy. Subjects received TE 100 mg im on d 1 and continued at weekly intervals. All TE injections were administered by medical personnel with the exception of a few subjects who lived far away from the study center. These subjects were given instructions on self-injections. All subjects underwent treatment for 24 wk and then completed a recovery period of 3–6 months until return of two consecutive sperm concentrations to the subject’s average pretreatment level or more than 20 x 106/ml. This study was approved by the Institutional Review Board of the Harbor-UCLA Research and Education Institute. All study subjects gave informed written consent.
All subjects had complete physical exams and interviews done by a physician at screening and wk 6, 12, 24, 36, and 48. Semen analysis was performed every 3 wk on samples obtained by masturbation after at least 48 h of abstinence during the 24-wk treatment period and monthly during the recovery phase until sperm count returned to baseline levels. Blood samples were obtained before administration of T patch, TE injection, or oral LNG every 3 wk for serum T, free T, SHBG, FSH, and LH measurements. Serum LNG levels were also measured every 3 wk until wk 28 in subjects with Norplant II implants. In group 2, eight subjects had delayed application of transdermal T patch until wk 3 to allow for the measurement of serum levels of LNG without the possible interference by the T administration. In these subjects, serum LNG levels were measured at 1, 2, 4, and 8 h, and on days 1, 2, 3, 4, 5, 7, 10, 14, and 21 after Norplant II insertion, and days 1, 2, 3, and 7 after Norplant II removal. In addition, serum hormone levels for LH, FSH, and SHBG were drawn on d 2, 3, 4, 5, 7, 10, and 14 after Norplant II insertion. In another seven subjects receiving oral LNG and T patches, additional serum LNG levels were measured before and at 0.5, 1, 2, 4, 8, and 24 h after the oral dose of LNG on wk 12. Fasting safety laboratory tests including serum lipid profile and prostate-specific antigen (PSA) levels were drawn at screening and at wk 12, 24, and 36. Subjects completed a 7-d sexual diary before treatment, every 6 wk during the treatment phase, and at posttreatment wk 36 and 48.
Methods
Serum LNG was measured by RIA after extraction with hexane and ethyl acetate using reagents obtained through Saulat Sufi, Ph.D., from the WHO Collaborating Center (London, UK). The lower limit of quantitation (LOQ) of LNG in serum measured by this assay is 125 pmol/liter. The intra-assay and interassay coefficients were 6.2% and 8.1%, respectively. Serum T levels were measured after extraction with ethyl acetate and hexane by a specific RIA using reagents from ICN Biochemicals, Inc. (Costa Mesa, CA). The LOQ of serum T measured by this assay was 0.87 nmol/liter. All results below this value were reported as 0.87 nmol/liter. The mean accuracy (recovery) of the T assay, determined by spiking steroid free serum with varying amounts of T (0.9–52 nmol/liter), was 104% (range, 92–117%). The intra- and interassay coefficients of the T assay were 7.3% and 11.1%, respectively, at the normal adult male range, which in our laboratory were 10.33–36.17 nmol/liter (298–1043 ng/dl), respectively. Serum free T was measured by RIA in the dialysate after equilibrium dialysis using reagents provided by ICN Biochemicals, Inc./Nichols (San Juan Capistrano, CA). The LOQ for this assay is 0.03 nmol/liter. The intra- and interassay coefficients were 12.9% and 21.5%, respectively. The normal range was 0.12–0.62 nmol/liter. Serum FSH and LH were measured by the highly sensitive and specific fluoroimmunometric assays with reagents provided by Delfia (Wallace, Gaithersburg, MD). The intra-assay coefficients of variation for LH and FSH were 4.3% and 5.2%, respectively; and the interassay variations for LH and FSH are 11.0% and 12.0%, respectively (adult normal male range, LH, 1.0–8.1 IU/liter; FSH, 1.0–6.9 IU/liter). For both LH and FSH assays, the LOQ is determined to be 0.2 IU/liter. SHBGs were measured by fluoroimmunometric assay with reagents provided by Delfia. The LOQ is determined to be 0.5 nmol/liter. The intra- and interassay coefficients were 2.3% and 6.1%, respectively. The normal range for this assay is 10.8–46.6 nmol/liter. All samples from a subject were measured in an assay to minimize interassay variability. When results were below the LOQ, the LOQ value was reported and used in data analysis.
Semen samples were collected by masturbation after 48–72 h of abstinence into sterile plastic containers and were analyzed after liquefaction. Semen analyses were performed according to the recommended methods described in the WHO Laboratory Manual for the Examination of Human Semen and Sperm-Cervical Mucus Interaction (13). Sperm concentration was assessed using the hemocytometer method, and visual assessment was used for motility and morphology.
Sexual function and mood were assessed by questionnaires that the subjects answered daily for 7 consecutive days before clinic visits. The subjects recorded whether they had sexual daydreams, anticipation of sex, flirting, sexual interaction (sexual motivation parameters) and orgasm, erection, masturbation, ejaculation, intercourse (sexual performance parameters) on each of 7 d. The value was recorded as 0 (none) or 1 (any) for analyses, and the number of days the subjects noted a parameter was summed for the 7-d period. The average of the four sexual motivation parameters was taken as the sexual motivation score, and that of the five sexual performance parameters was taken as the sexual performance mean score (0–7). The subjects also assessed their level of sexual desire, sexual enjoyment, and satisfaction of erection using a seven-point Likert-type scale (0–7) and the percentage of full erection from 0–100%. The subjects rated their mood using a 0–7 score. The parameters assessed included the following positive mood responses: alert, friendly, full of energy, and well/good feelings; and negative mood responses: angry, irritable, sad, tired, and nervous. Weekly average scores were calculated. The details of this questionnaire had been described previously (14, 15). T patch compliance was assessed by asking the subjects to bring back both used and unused patches for counting. LNG pills were also assessed by pill counting at each visit.
Statistical analysis
Descriptive statistics, either means and SD values or frequency distributions, were calculated for each variable at each time period. Outcome variables such as semen parameters, FSH, LH, T, free T, and SHBG levels were analyzed using ANOVA. One-way ANOVA was used for comparison of groups on baseline measures or change at 24 wk. Pairwise comparisons were made using the Student-Newman-Keuls test. Repeated measures ANOVA was used to analyze the longitudinal course of the outcome variables. Time in treatment (including control values) was included as the repeated (within subject) factor in the ANOVA and treatment, as between the subject factors. Differential effects of different treatments were assessed by testing for significant interactions between time and treatment. Comparisons of baseline to final values within groups during treatment were made using paired t tests. Comparisons of rates of azoo- or oligozoospermia in two or four groups were made using Fisher Exact test. Type 1 error was set at 0.05, and actual P values were reported to provide further information on the strength of the finding. The results are represented as mean ± SEM.
Results
Baseline clinical and biochemical characteristics of the 68 subjects at the time of randomization are shown in Table 1
. The parameters were all within the normal range and not significantly different among the four groups.
Sperm concentration
Analysis of the primary outcomes (semen parameters) comparing subjects with delayed T patch application (wk 3) to those who began T patch at the start of treatment phase (d 1) in the Norplant II plus T patch group showed no significant differences; therefore, they were included as a single group in the subsequent analyses of the semen parameters.
Figure 1 shows the sperm concentration of the subjects in logarithmic scale. Spermatogenesis was least suppressed in the T patch alone group (50% of baseline concentration) and most marked in the Norplant II plus TE group (7–11% of baseline), whereas the T patch plus Norplant II (21–29% of baseline) and T patch plus oral LNG (28–38% of baseline) were in between. Sperm motility decreased in all groups and followed the same pattern as that of sperm concentration (data not shown). Mean sperm motility (in the subjects with spermatozoa in the ejaculate) in the Norplant II plus TE group were suppressed to less than 10% from wk 15 onward. Recovery of sperm concentration and motility was complete by 16 wk after withdrawal of treatment.
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shows that the Norplant II plus TE group achieved significantly greater suppression of spermatogenesis in more subjects compared with the other three groups (four group comparison, P = 0.0001). Severe oligozoospermia (<1 x 106/ml) was achieved in 60% of Norplant plus T patch compared with 24% in the T patch only group (P = 0.0453; Fig. 2, top panel) and 100% in the Norplant plus TE, compared with 42% in the LNG plus T patch (P = 0.0012; Fig. 2, bottom panel). The rate of achievement of azoospermia was also significantly different among the four groups (P = 0.003). Azoospermia was achieved in 35% of Norplant plus T patch vs. 24% in T patch only group (not significant); and 93% in the Norplant plus TE compared with 33% in the LNG plus T patch group (P = 0.0029). Persistent suppression to sperm concentration to less than 3 x 106/ml was achieved in all subjects from treatment wk 12 to end of treatment in the Norplant plus TE group.
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Serum LNG levels reached a peak (1900 ± 97 pmol/liter) 4 d after Norplant capsule insertion (Fig. 3, right top inset). Thereafter, the levels fell slightly, and steady-state serum LNG levels ranging between 800 and 1200 pmol/liter were attained throughout the treatment period (Fig. 3). Serum LNG levels returned to baseline levels 3 d after the Norplant capsules were removed (data not shown). In the oral LNG plus T patch group, throughout the treatment period, mean trough serum LNG levels were maintained between 940 and 1300 pmol/liter (Fig. 3). At wk 12, the serum LNG level was 1080 ± 201 pmol/liter before oral LNG administration. Serum LNG levels reached a peak of 1907 ± 372 pmol/liter 30 min after oral administration, and levels were then maintained between 1000 and 1300 pmol/liter until the next dose at 24 h (Fig. 3, right bottom inset).
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Both serum LH and FSH levels were significantly suppressed in all groups during the treatment period compared with baseline (P = 0.0001; Fig. 4). In the eight subjects with delayed T patch application, mean serum LH and FSH levels were suppressed by Norplant II alone (wk 3, serum LH, 2.92 ± 0.78 IU/liter; serum FSH, 1.69 ± 0.35 IU/liter) but were further suppressed when T patch was applied (wk 6, serum LH, 1.65 ± 0.58 IU/liter; serum FSH, 0.75 ± 0.25 IU/liter; Fig. 2, insets). Serum FSH levels were significantly more suppressed in the Norplant plus T patch group compared with T patch only group (P = 0.0139; Fig. 4, top panel). In the Norplant II plus TE group, mean serum FSH was suppressed to less than 0.5 IU/liter from wk 3–24. In many subjects, the serum FSH levels were below the LOQ. Mean serum LH levels were less than 0.5 1U/liter throughout the treatment period and were also suppressed to below the LOQ in the Norplant II plus TE group in most subjects. Suppression of LH was less marked and not to the LOQ in the groups treated with T patch alone, T patch plus Norplant II, or oral LNG. Both serum LH and FSH levels returned to baseline levels during the recovery period.
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Mean serum SHBG was not decreased in the T patch alone group but was suppressed to 58%, 69%, and 53% of baseline values in T patch plus Norplant II, T patch plus oral LNG, and Norplant II plus TE groups, respectively (Fig. 5). To show that Norplant II suppressed SHBG levels even in the absence of androgens, in the eight subjects whose T patch application was delayed for 3 wk, mean serum SHBG was suppressed from 38.2 ± 2.9 nmol/liter at baseline to 29.3 ± 1.4, 23.4 ± 2.8, and 22.2 ± 2.1 nmol/liter at wk 1, 2, and 3, respectively, when the subjects were exposed to Norplant alone (P = 0.0001) and not further suppressed (20.7 ± 2.3 nmol/liter at wk 6) after T patch was applied (Fig. 5, inset).
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Serum total and free T concentrations are shown in Fig. 6, top and bottom panels. Serum total T levels remained within the adult normal range in all groups throughout the treatment period. In the T patch alone group, mean serum T levels were higher than baseline at wk 3, 6, and 9 (P = 0.0070, 0.0223, and 0.0424, respectively). Mean serum total T levels were lower in all three groups with a progestagen component (Fig. 6, top panel). The lower serum total T concentrations in the T patch plus Norplant II, T patch plus oral LNG, and Norplant II plus TE groups might be related to the decrease in SHBG levels resulting in lower SHBG-bound T fractions. Serum free T levels showed no significant change from baseline, remained within normal range, and were not different between the four groups throughout the treatment period (Fig. 6, bottom panel). Figure 2 insets show the mean serum total T and free T levels in the eight subjects in the Norplant II plus T patch group who applied T patches at wk 3 during the treatment phase. In these subjects with delayed T patch application, mean serum T and free T concentrations were significantly decreased at wk 3 (P = 0.001 and 0.010, respectively) when compared with baseline, remained within the low normal range, and returned to their baseline values by wk 6 after T patch application.
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Analyses of the psychosexual diaries collected for 7 d before clinic visits showed that the sexual motivation and performance scores as well as the positive (alert, friendly, full of energy, well/good feelings) and negative (angry, irritable, sad, tired, nervous) mood summary scores were not significantly changed with all treatment groups (data not shown).
Body weight, testis volume, and safety parameters
There was no significant change in body weight in all four groups during and after treatment (Table 2). The mean left or right testis weight decreased by 2–8 ml from baseline in the four groups. The mean decrease in testis volume was most marked in the Norplant II plus TE group at wk 24 (left testis volume decreased by 7.2 ± 1.1, and right by 8.9 ± 1.0 ml from baseline volumes). None of the subjects appreciated the change in testis size.
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Adverse effects
Mild asymptomatic gynecomastia (increased breast tissue within the areola region) was found in nine patients (seven in the Norplant plus T patch, two in the T patch group). Mild acne on the face or trunk occurred in 10 subjects during the treatment period (3 in the Norplant plus T patch, 4 in the T patch, 3 in the Norplant plus TE group), with spontaneous resolution occurring during treatment period or after treatment withdrawal. Mild dermal irritation described as mild erythema on T patch application sites (upper buttocks and upper arms) occurred in six subjects and was reduced by changing or rotating T patch application sites. One subject developed generalized hives to the T patches after first application and was immediately terminated from the study. Two subjects reported mild increase in emotional irritability and anger (one in the Norplant plus TE, one in the oral LNG plus T patch) in the first few weeks of the study, which resolved requiring no intervention. Two subjects developed transient decrease in libido. There was one serious adverse event unrelated to the treatment. This subject, in the T patch only group, did not disclose his past psychiatric history of multiple depressive episodes at enrollment. He developed depression 12 wk into the treatment phase, attempted suicide, and was admitted to a psychiatric ward for observation. He was discontinued from the study.
Discussion
This study has explored the effects of different T and progestagen (LNG) delivery systems on suppression of spermatogenesis in experimental male contraceptive regimens. We chose Norplant II as a depot to provide a relatively steady delivery of progestagen. Placebo implants were not considered justified because of the requirement of minor surgical procedures for insertion and removal. Despite their ability to achieve steady serum T levels in this study, T pellets were not used as a T delivery system because of reports of significant extrusion rate and the requirement of another surgical procedure to insert the pellets at another site (11). As a less invasive alternative, we elected to use transdermal T patches at twice the dose recommended for androgen replacement in hypogonadal men. This dose was selected because a previous report found that a single transdermal T patch delivering 5 mg/d was not efficient in suppressing spermatogenesis even in combination with oral LNG (16). The T patch alone group was necessary for comparison with other groups because the effect of T patches designed to deliver 10 mg/d transdermally on suppression of spermatogenesis had not been previously studied in normal volunteers. When the preliminary data in the initial two groups (T patch alone and T patch plus Norplant II) showed that these treatment regimens were unable to achieve marked suppression of spermatogenesis to the same degree as previous studies, we added two additional groups to address the question of whether the route or dose of the androgen (T patch) or progestagen (Norplant II) was the main cause for this failure.
We showed in this study that Norplant II, two systems (four capsules), provided steady-state serum levels of LNG within 2 wk after insertion. This concentration was maintained throughout the treatment period of 6 months. Serum LNG concentration then returned to LOQ levels 3 d after implant removal, indicating that significant accumulation is unlikely. The steady-state serum LNG levels achieved with Norplant II are equivalent to the trough serum LNG concentrations achieved after oral administration of 125 µg LNG and comparable to those from prior studies in women (17), suggesting similar bioavailability of Norplant II in both sexes. The four LNG implants (Norplant II) were well- tolerated in men. There were no problems with implant insertion or removal. Norplant II implants alone suppressed serum LH and FSH levels. Addition of T patches to Norplant II further suppressed serum gonadotropins, although not to the lowest levels possible. We showed that Norplant II plus T patch achieved azoo- or oligozoospermia in 60% of men and was more effective than T patch alone (24% of men became azoo- or oligozoospermic), thus confirming the additive effect of progestagens to androgens in the suppression of spermatogenesis. This observation is in agreement with others who demonstrated a more rapid and effective suppression of spermatogenesis with either oral (LNG or desogestrel) or injectable progestagens (depot-medroxyprogesterone and norethisterone enanthate) in combination with TE and TU injections or T pellets (7, 8, 9, 10, 11, 12).
Despite the achievement of serum LNG levels similar to the trough concentrations after orally administered LNG, Norplant II plus T patch was less efficacious in achieving severe azoo- and oligozoospermia (60%) than that of previous reports (89–94%) using oral LNG 125–500 µg /d plus TE injections (100 mg weekly) (7, 8). To determine whether the route of administration of LNG was responsible for the modest response of Norplant II plus T patch, Norplant II was substituted by oral LNG at a dose that previously was shown to enhance spermatogenesis suppression by androgens (7, 8) and used in combination with T patch; a low rate of azoo- or severe oligozoospermia (42%) was again achieved. The finding that suppression of sperm counts was not better with oral LNG plus T patch than that achieved with Norplant II and T patch indicated that Norplant II was probably not the reason for the poor spermatogenic suppression. We then considered that the blood levels of T might be responsible for the poor sperm suppression effects when testosterone (T) patch was used as the source of T. Throughout the treatment period, T transdermal patch designed to deliver10 mg/d T provided total and free T levels within the normal range. The total T levels achieved with 10 mg/d T patch alone in our subjects were about twice those achieved with T patch 5 mg/d (16) but lower than the peak levels achieved with TE 100 mg/wk (18). Our results were comparable to the study of Buchter et al. (16), in which, after administration of lower doses of a similar T patch (5 mg/d) plus oral LNG 250 to 500 µg/d, only 46% of the subjects became azoo- or oligozoospermic. These investigators suggested that the transdermal patches might not have delivered adequate T into the circulation to exert an additive effect on the gonadotropin suppression induced by progestagens, and our data support this conclusion.
Thus, we conclude that the low efficacy of Norplant II and T patch was most likely due to the relatively lower circulating T levels provided by the transdermal T patch than with injectable T. It is also possible that the observed unsatisfactory suppression of gonadotropins and spermatogenesis by the LNG plus T patch combinations was due to poor compliance in some of the subjects. It should be noted that the serum T levels after T patch administration were higher than baseline at wk 3–9 in the group of subjects taking T patch alone. Thereafter, serum T levels decreased, which could be explained by poorer compliance or poor adherence of the patches at the latter part of the study in some subjects. Patch counting did not suggest evidence of noncompliance. Although not systematically analyzed, there were reports of problems with adherence of the patch to the skin in some subjects. We were also interested in the effect of the progestagen on measured T levels. Although serum total T appeared to be lower in the groups receiving progestagen and T combinations, the free T concentrations were similar in all treatment groups. This occurred because progestagens (Norplant II and oral LNG) lowered serum SGBH levels, thus lowering total but not free T levels. Consistent with the finding of unchanged serum free T levels, there were no significant changes in sexual function or mood in any of the four treatment groups.
To complete this study on the route of administration of T and LNG on suppression of spermatogenesis, we substituted the T patches with TE injections at the dose previously reported to have additive/synergistic effects with other progestagens (7, 8, 9, 10), TE (100 mg/wk) with Norplant II. The latter combination was very effective, resulting in all subjects achieving severe oligozoospermia (<1 x 106/ml) and 93% reaching azoospermia. Concomitant with the marked suppression of sperm concentration, serum FSH and LH levels were markedly suppressed in this group of subjects. Although not specifically tested in these studies, it is unlikely that such a high rate of azoospermia after Norplant II plus TE was due to the TE at 100 mg/wk alone. We base this conclusion on prior studies showing that TE administered at 100 mg/wk im suppressed sperm concentrations to azoospermia in only 33% and oligozoospermia (<3 x 106/ml) in 61% of the subjects (7). Other small-scale studies also demonstrated that TE at 100 mg/wk suppressed spermatogenesis to azoospermia in not more than 50–60% of non-Asian men (18, 19, 20, 21). Furthermore, even at twice the dose, TE 200 mg/wk induced azoospermia in only 60–70% of subjects in a large-scale study in non-Asian centers (1, 2). On the basis of these results, we conclude that the dose or the route of administration of T was very important for androgens to exert an additive effect to progestagens in the inhibition of spermatogenesis, and this enhanced effect was likely to be the result of greater gonadotropin secretion suppression.
LNG implants have been studied in two other contraceptive trials. In one study, combinations of up to four capsules of Norplant II were administered together with dihydrotestosterone (DHT) transdermal gel (10 g of 2.5% gel/d) compared with DHT gel applied alone. The number of subjects who completed each arm of the study was very small; none of the subjects suppressed to azoospermia and very few to oligozoospermia. At the dose used, DHT alone did not suppress gonadotropin levels; the combinations of two and four Norplant II capsules with DHT appeared to decrease both serum LH and FSH levels (22) demonstrating an additive action of progestagens and androgens on gonadotropin suppression. In another study in 16 Chinese men, two LNG implants (Sino-implant, each rod containing 75 mg LNG) together with a long-acting T ester, TU 250 mg im monthly, resulted in azoospermia in only six subjects (23). The serum LNG levels produced by Sino-implant (0.24 ng/ml = 748 pmol/liter) were lower than the serum LNG levels achieved by Norplant II (four capsules) or oral LNG (125/µg·/d) reported in our present study. Although the serum T concentrations were not reported in the Chinese study, the TU dose used was only about half of that recommended for hypogonadal men (TU, 500 mg every 4 wk or 1000 mg every 8–12 wk; Refs. 24 , 25).
Other studies have looked at combinations of other progestagens and androgens. Studies involving a small number of men (about seven to eight in each group) reported that oral desogestrel at 300 µg/d when combined with TE at 50–100 mg/wk im resulted in suppression of sperm output to severe oligozoospermia in 88–100% of subjects. When the desogestrel dose was reduced to 150 µg/d, it was observed that the dose of TE appeared to be very important because, when combined with TE 100 mg/wk, the oligozoospermic rate remained very high (100%), whereas with TE 50 mg/wk the oligozoospermic rate was down to 67% (9, 10). Oral desogestrel with T implants has been shown to suppress spermatogenesis to severe oligozoospermia in 100% of subjects and might be a promising approach, but this involves the daily pill use (26, 27). Kamischke et al. (28) using TU (1000 mg every 6 wk im) with and without oral LNG (250 µg/d) showed that 8 of 14 reached azoospermia in the group without LNG, compared with 7 of the 14 subjects in the group with LNG. They concluded that LNG did not demonstrate a major effect on spermatogenesis suppression when used in combination with injectable TU. It should be noted that TU (1000 mg) given at six weekly intervals results in accumulation of T, resulting in serum levels in the high or above normal range after multiple injections (29). This is due to the long-acting nature of this T ester compared with TE. We cannot easily explain the lack of a further additive effect of oral LNG to TU in this study; however, the TU alone administered at high doses resulted in a large suppression of spermatogenesis, and the additive effects of progestagens may not be apparent in small-scale clinical trials.
We were also interested in the effects of Norplant on weight gain and HDL-cholesterol levels in men. Previous studies reported significant weight gain in subjects administered oral LNG (desogestrel) with TE injections (7, 8, 9, 10). In our subjects, the weight gain was minimal and insignificant. Prior studies also reported that oral LNG at 250–500 µg/d lowered HDL by 21–28%; this decrease in HDL-cholesterol level was dependent on the dose of progestagens administered (7, 8). Substituting desogestrel for LNG did not result in less suppression of serum HDL-cholesterol levels (9, 10). In our study, addition of Norplant II to T patch did not further suppress HDL-cholesterol levels significantly. In the Norplant II plus TE group, the suppression of HDL levels was slightly more pronounced (-12%) than with Norplant II plus T patch; this HDL-cholesterol suppression was similar to that reported with the lower dose oral LNG (125 µg/d) and TE combination and less than that reported with higher dose LNG and TE (>20% decrease; Refs. 7 , 8). There were no other significant changes in safety parameters. The presence of acne and gynecomastia after treatment were mild and transient.
In summary, our study confirmed the additive suppressive effects of progestagens to androgens on gonadotropin secretion and spermatogenesis. We showed that although steady serum levels of LNG were maintained by Norplant II at concentrations comparable to those achieved after oral administration and serum T concentrations at the mid- normal range were provided by transdermal patch delivery, the suppression of spermatogenesis was inadequate for male contraceptive purposes. When transdermal T patch was substituted by injectable T ester, the combination (Norplant II plus TE) was highly effective. This demonstrates the critical role of androgens in androgen-progestagen combinations used for male contraceptive development. The dose and the route of delivery of androgens may determine whether a contraceptive steroid combination would be useful. When higher doses of androgens are used, resulting in serum concentrations in the high-normal range, then the addition of progestagens may not have additive effects. It also appears that the balance between the dose of androgens and progestagens may also be important in achieving the maximal suppression of gonadotropins and spermatogenesis. We propose that Norplant II might be a candidate for the progestagen component of a long-acting, provider-dependent, male hormonal contraceptive method. We speculate that the use of Norplant II with an implantable androgen would be highly effective and may be developed into a long-acting method of hormonal male contraception.
Acknowledgments
We are grateful to Harold Nash, Ph.D. (Population Council, New York, NY) for providing LNG implants (Norplant II systems, Jadelle); Linda Atkinson, Ph.D. (Alza Corp., Mountain View, CA) for providing T patches; Michael Gast, M.D. (Wyeth-Ayerst Laboratories, Inc., Philadelphia, PA) for providing the LNG; Alvin Matsumoto, M.D. (Department of Medicine, VA Puget Sound Health Care System, University of Washington, Seattle, WA), for helping with the preparation of LNG capsules; the staff of the Endocrine Research Laboratory and the Harbor-UCLA GCRC Core Laboratory for the hormone assays and semen analysis; the GCRC at Harbor-UCLA for providing the skilled nursing assistance; Laura Hull for data management; and Sally Avancena and Daisy Sigüenza for manuscript preparation.
Footnotes
Support for this project was provided by the CONRAD program (CSA-97-203, CSA-99-256), Eastern Virginia Medical School, under a cooperative agreement (HRN-A-00-98-00020-00) with the U.S. Agency for International Development (USAID). The views expressed by the authors do not necessarily reflect the views of USAID or CONRAD. This project was performed at the GCRC at Harbor-UCLA Medical Center supported by NIH Grant MO1-RR00425.
This study was presented in part at the 82nd Annual Meeting of The Endocrine Society, Toronto, Canada, June 2000, and the Seventh International Congress of Andrology, Montreal, Canada, June 2001.
Abbreviations: CONRAD, Contraceptive Research and Development; DHT, dihydrotestosterone; GCRC, General Clinical Research Center; HDL, high-density lipoprotein; LDL, low-density lipoprotein; LNG, levonorgestral; LOQ, limit of quantitation; PSA, prostate-specific antigen; T, testosterone; TE, T enanthate; TU, T undecanoate; WHO, World Health Organization.
Received November 1, 2001.
Accepted April 17, 2002.
References
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|
|
|
|
|
|
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|
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|
|
|
|
|
|
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|
|
|
|
 |
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
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|
|
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|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
R. A. Anderson and D. T. Baird Male Contraception Endocr. Rev., December 1, 2002; 23(6): 735 - 762. [Abstract] [Full Text] [PDF]
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, T patch only; 
, Norplant II plus T patch; 
, oral LNG plus T patch; and •, Norplant II plus TE injections. Pre TX, Pretreatment.
