The combined use of oral medroxyprogesterone acetate and methyltestosterone in a male contraceptive trial programme

Acceptability of the oral hormonal male contraceptive prototype, 11β-methyl-19-nortestosterone dodecylcarbonate (11β-MNTDC), in a 28-day placebo-controlled trial

OBJECTIVE

To determine men's satisfaction with and the potential acceptability of 11β-methyl-19-nortestosterone dodecylcarbonate (11β-MNTDC) when used for 28 days as an experimental, once-daily, oral hormonal male contraceptive (HMC).

STUDY DESIGN

We surveyed participants from a double-blind, randomized, placebo-controlled, phase 1 clinical trial, examining their experience with and willingness to use daily oral 11β-MNTDC for male contraception.

RESULTS

Of 42 trial participants, 40 (30 11β-MNTDC, 10 placebo) completed baseline and end-of-treatment surveys. Based on a 28-day experience, few cited any baseline concerns about safety and drug adherence. Following treatment, nearly three-quarters (72.5%) of participants reported satisfaction with the study drug and nearly all (92.5%) would recommend the method to others. More than half of participants would be willing to pay for the study drug (62.5%) and indicated that the method exceeded initial expectations (53.9%). Nearly 90% reported that taking the pill was easy to remember and did not interfere with their daily routines. Approximately one-third of participants reported bothersome side effects (37% 11β-MNTDC vs. 20% placebo, p = 0.45). Given the option, 42% of participants would prefer a daily HMC pill over injectable regimens or a daily topical gel.

CONCLUSION

A majority of participants in this short-term trial of daily oral 11β-MNTDC reported satisfaction with the regimen, would recommend it to others, and would pay to use the drug as HMC despite some bothersome side effects.

IMPLICATIONS

Oral 11β-MNTDC would be an acceptable and preferable method among men desiring reversible hormonal male contraception (HMC). These data support further trials of novel oral HMCs such as 11β-MNTDC.

Male contraception: history and development

Although the twentieth century has seen great strides in the development of female contraception, not a single new agent has been introduced as an approved method for common use for male contraception. Condoms (considered uncomfortable by some) and vasectomy (a permanent invasive procedure) are the only options provided to men, leaving an undue burden on women to bear contraceptive responsibility. Significant developments have, however, been made with regard to hormonal and nonhormonal contraception, and minor, reversible, procedural contraception. This article reviews the currently available, soon to be available, and theoretically possible methods of male contraception.

A non-human primate study (baboon; Papio hamadryas) to determine if a long-acting progestogen, levonorgestrel butanoate, combined with a long-acting androgen, testosterone buciclate, can suppress spermatogenesis: II. Efficacy study

Two combined injections of levonorgestrel butanoate (4 mg/kg) and testosterone buciclate (8 mg/kg) at 3-month intervals to adult male baboons initiated a decrease in sperm concentration from baseline values of 490x10(6)/ml to minimum values of 17x10(6/ml. This suppression was sustained until week 32, during which time between one and three azoospermic samples were collected from each of four out of five treated baboons in the period 10-24 weeks. Circulating plasma levels of LH and testosterone decreased to approximately 20-75% of baseline values. Plasma levels of cortisol declined to significantly reduced levels at weeks 22 and 36-44. All values returned to the baseline range by week 48. The combined administration of progestogen and androgen induced a more marked and sustained suppression to severe oligozoospermia or azoospermia than did the equivalent dose of progestogen alone (Goncharov et al., 1995). Although the dose of testosterone buciclate used did not maintain peripheral levels of testosterone in the normal range, it did not restimulate spermatogenesis. It was concluded that a combination drug regimen based on the novel long-acting levonorgestrel and testosterone esters could provide a contraceptive option for men.

Phthalate esters and semen quality parameters

Analysis of reports in the world's literature suggests that average sperm densities for groups of unselected males were relatively constant at about 108 million cells per ml prior to 1950. Subsequent to that time mean sperm densities appear to have declined. Regression analysis indicates the existence of significant negative correlations between mean sperm densities and production of synthetic organic chemicals among other parameters. Phthalate esters are one class of large volume organic chemicals that are known to disturb testicular function in laboratory animals. These compounds are also the most abundant man-made chemicals in the environment. Plots of the concentration of dibutylphthalate in the cellular fraction of ejaculates against either the sperm density or the total number of sperm for the same ejaculates gave two clusters of points. These clusters suggest the existence of two or more populations vis à vis phthalate metabolism; both of which show a negative correlation between phthalate concentration and sperm production.

Intratesticular steroid levels and their hormonal control

Litter-mate adult male rats were treated with daily intramuscular injections of ACTH (10.5 micrograms), dexamethasone (2.0 mg), ethynyl estradiol (1.7 micrograms) and hCG (5 IU) for three consecutive days. The animals were sacrificed on the fourth day and the intratesticular and peripheral plasma steroid levels were analyzed. The steroids measured by radioimmunoassay included pregnenolone, 17-hydroxypregnenolone, dehydroepiandrosterone, progesterone, 17-hydroxyprogesterone, androstenedione, testosterone and dihydrotestosterone. In addition, the sulphoconjugated forms of pregnenolone, dehydroepiandrosterone, testosterone and dihydrotestosterone were estimated in the peripheral blood. The administration of ACTH diminished the intratesticular levels of all steroids studied. Also dexamethasone and ethynyl estradiol treatment suppressed all intratesticular steroid levels, except that of pregnenolone (the former) and of 17-hydroxyprogesterone (the latter). The suppressive effect of ethynyl estradiol was strongest on the levels of the delta 5-steroids and that of dexamethasone on the delta 4-steroids; the latter was significantly stronger than the effect of ACTH. The stimulatory effect of hCG was limited to the metabolism of progesterone and was restricted to the sequence: 17-hydroxyprogesterone----androstenedione----testosterone---- dihydrotestosterone. Dexamethasone-suppression, and hCG-stimulation of the intratesticular levels of delta 4-steroids, was mirrored by corresponding changes in the peripheral plasma levels, with the exception of the plasma levels of androstenedione which were not influenced by any of the treatments studied. Also the suppression of intratesticular testosterone and dihydrotestosterone levels by ACTH, dexamethasone, or ethynyl estradiol was closely reflected by their plasma levels both in the unconjugated and sulphoconjugated forms. On the hand, the administration of ACTH diminished the intratesticular levels of pregnenolone and progesterone but significantly increased those in the plasma. Moreover, both ACTH and ethynyl estradiol reduced the levels of all delta 5-steroids in testicular tissue, but not in the peripheral plasma, although they decreased the circulating levels of pregnenolone sulphate and dehydroepiandrosterone sulphate. The data are interpreted as suggesting that the hormonal agents studied interfere with testicular steroidogenesis through different mechanisms.

The effect of oral medroxyprogesterone acetate and methyltestosterone on sexual functioning in a male contraceptive trial

Twenty-three men who participated in a 15-month clinical trial to assess the potential effectiveness of using a combination of varying doses of medroxyprogesterone acetate (MPA) and methyltestosterone (MT) as a male contraceptive agent, completed a "sexual problem checklist" every two weeks. The study was divided into three phases: pre-treatment (3 months), treatment (6 months), post-treatment (6 months). The questionnaire evaluated changes in various aspects of sexual behaviour and sexual perception and explored whether the treatment influenced any of the parameters considered. The results indicated a small, but significant, decrease in subjective assessment of sexual drive. This was not, however, accompanied by a change in sexual behaviour, in that subjects experienced the same number of erections, ejaculations and frequency of intercourse. It is concluded that the combination of MPA and MT in the doses used may produce a slight decrease in subjective assessment of sexual drive, but no change in actual sexual behaviour.

Content of reports on clinical trials: a critical review

A 10% sample of English language papers, published in 1980, listed in Index Medicus, and classified under the heading, Clinical Trials, was used to assess the state of trials and reports from them. Tabulations are presented concerning the design of the trials represented by the papers in the sample. The manuscript concludes with a discussion of reporting responsibilities for investigators involved in trials and of methods for meeting those responsibilities.

A rapid method for the determination of 5 alpha-dihydrotestosterone in Thai males receiving medroxyprogesterone acetate

A rapid method for the determination of DHT (5 alpha-dihydrotestosterone) in serum was established, utilizing potassium permanganate as an oxidising agent to convert the double bond at position 4-5 of testosterone to dihydroxy alcohols. DHT was then extracted with diethyl ether and measured directly using radioimmunoassay technique. The precision of the assay was determined at three levels of DHT added into pooled serum and found to be 4.4-5.1% for between assay percentage coefficient of variation. The sensitivity of the standard curve was found to be 4.2 pg/0.5 ml sample. The accuracy was determined in pooled serum with added standard DHT in the range of 80-800 pg. The percentage recovery of the assay was found to be 92.93-98.35%. The antisera used for DHT assay exhibited no significant cross-reaction with various steroids tested except testosterone which showed a 91.3% cross-reaction. The method was applied to measure the level of DHT in serum of Thai males receiving medroxyprogesterone acetate (MPA) as an oral contraceptive. Twenty-five subjects were divided into 5 groups. Group 1 received an oral placebo with monthly sesame oil injection. Groups 2, 3 and 4 received 5 mg, 10 mg and 20 mg MPA, respectively, with the addition of monthly injection of 250 mg testosterone enanthate (TE). Group 5 received 20 mg MPA daily with the addition of monthly injection of 500 mg TE. Blood specimens were obtained monthly. The first 4 months were used as a control period. After the 4-month period, each subject received treatment as mentioned above for 6 months, then follow-up study was resumed for another 6 months. The results revealed that subjects receiving 20 mg MPA with the addition of 250 mg TE showed a significant decrease of DHT levels (p less than 0.001).