Daily Oral Administration of the Novel Androgen 11β-MNTDC Markedly Suppresses Serum Gonadotropins in Healthy Men

Synthetic androgens for male contraception

High global rates of unintended pregnancy (>40% of all pregnancies) are relatively stagnant despite a broad array of female contraceptive options. Data suggest many men are enthusiastic to utilize novel, reversible, male contraceptives, particularly those that may be administered orally. Hormonal male contraception utilizes androgens or androgen-progestin combinations to exploit endocrine negative feedback, interrupting the hypothalamic-pituitary-testicular axis to suppress spermatogenesis. Modifications of testosterone allow for tailoring of steroid activity and show promise as single agent hormonal male contraceptives. The addition of progestin activity by molecular modification of testosterone could enhance the degree and speed of sperm suppression compared to testosterone alone using a single, exogenous steroid. Moreover, modifications that block reduction of testosterone to dihydrotestosterone could diminish androgenic stimulation of prostate tissue. This review summarizes data in the development of modified androgens for male hormonal contraception and suggest a path forward for these molecules in helping to fill the gap in contraceptive technologies for men.

New endocrine method of oral male contraception

Essential for hormonal male contraception (HMC) is the inhibition of follicle-stimulating hormone (FSH), the hormone responsible for spermatogenesis. No drugs exist that can selectively suppress FSH without also inhibiting luteinizing hormone (LH), the hormone responsible for the biosynthesis of testosterone (T) and estradiol (E2) in men. The consequences are a loss of T and E2, with the accompanying symptoms and signs of T deficiency and E2 deficiency, respectively. The loss of T causes sexual function problems, including reduced libido and problems with erection and ejaculation. Moreover, T is not orally bioavailable, and there is a lack of suitable, orally bioavailable androgens to replace the loss of T. This has led to the use of nonoral T replacements, such as patches, gels, or parenteral administration of T or other androgens in current methods for HMC under development. In case these new HMC methods do not contain a testosterone preparation that is metabolized into E2, the suppression of LH will cause loss of E2 and symptoms of estrogen deficiency. We propose to investigate a new oral endocrine approach for HMC using a triple hormone drug called MANTE (Male oral contraception by a GnRH ANtagonist, Testosterone and an Estrogen). This method combines three novelties: (1) the use of an oral gonadotrophin-releasing hormone antagonist to suppress FSH and spermatogenesis, (2) a high dose of the natural adrenal androgen dehydroepiandrosterone to replace T, and (3) a low dose of an orally bioavailable estrogen, preferably estetrol (E4), to prevent signs and symptoms of estrogen deficiency.

Male Hormonal Contraception-Current Stage of Knowledge

Male hormonal contraception has been the focus of extensive research efforts aimed at identifying effective and reversible methods for male fertility control. This review summarizes the current state of knowledge, key achievements, and future directions in the development of male hormonal contraception. A review was conducted using the PubMed, Embase, and Scopus databases. The search strategy included terms such as "male hormonal contraception", "Nestorone", "7α,11β-Dimethyl-19-nortestosterone 17β-undecanoate (DMAU)" and "11β-methyl-19-nortestosterone 17β-dodecylcarbonate (11β-MNTDC)". A total of 107 references were analyzed to synthesize the most relevant findings regarding the hormonal contraceptive agents under investigation. The review outlines historical and recent advancements in male hormonal contraception, highlighting compounds that have demonstrated limitations in effectiveness, side effects, or inconvenient administration. Notable candidates under study include 7α-methyl-19-nortestosterone (MENT), DMAU, 11β-MNTDC, and the combination of segesterone acetate with testosterone in gel form. These agents show promise due to their ability to suppress follicle-stimulating hormone (FSH) and luteinizing hormone (LH), leading to effective spermatogenesis inhibition with minimal side effects. Additionally, the phenomenon of spermatogenic rebound is considered. Among the investigated agents, oral DMAU, 11β-MNTDC, and the Nestorone-testosterone gel appear to be the most promising candidates for male hormonal contraception due to their high efficacy, user-friendly administration, and favorable safety profiles. However, further large-scale clinical trials are necessary to confirm their long-term effects on human health and fertility, ensuring their viability as future contraceptive options.

The road to hormonal male contraception: End in sight?

The concept of a hormonal approach that sufficiently and reversibly suppresses spermatogenesis to the level required for effective contraception has been developed and tested over several decades. The reality of achieving this has been confirmed using both testosterone alone and combination methods using a progestogen with a physiological dose of testosterone, necessary to replace the lack of endogenous testosterone production by the suppressed testes. A range of both long-acting and self-administered combination methods are effective, including injection, implant and gel methods of administration, with up to 95% of men achieving sufficient spermatogenic suppression. New steroids are also being trialled. Surveys show the widespread willingness of men and their female partners to use novel male methods, suggesting the potential of this approach to contribute to global family planning and sustainable development goals. This approach to contraception can clearly be effective, and needs to move from relatively small scale testing to large scale pre-marketing trials: only then can information about long-term safety and real-world acceptability be obtained.

Testosterone and male contraception

PURPOSE OF REVIEW

Rates of unintended pregnancy have remained relatively stagnant for many years, despite a broad array of female contraceptive options. Recent restrictions on access to abortion in some countries have increased the urgency for expanding contraceptive options. Increasing data suggest men are keen to utilize novel reversible male contraceptives.

RECENT FINDINGS

Despite decades of clinical research in male contraception, no reversible hormonal product currently exists. Nestorone/testosterone, among other novel androgens, shows promise to finally move to pivotal Phase 3 studies and introduction to the marketplace.

SUMMARY

Hormonal male contraception utilizes androgens or androgen-progestin combinations to exploit negative feedback that regulates the hypothalamic-pituitary-testicular axis. By suppressing release of gonadotropins, these agents markedly decrease endogenous testosterone production, lower intratesticular testosterone and suppress spermatogenesis. The addition of a progestin enhances the degree and speed of sperm suppression. The androgen component preserves a state of symptomatic eugonadism in the male. There is growing demand and acceptance of male contraceptive options in various forms. As these formulations progress through stages of drug development, regulatory oversight and communication with developers around safety and efficacy standards and garnering industry support for advancing the production of male contraceptives will be imperative.

Practice and development of male contraception: European Academy of Andrology and American Society of Andrology guidelines

BACKGROUNDS

Despite a wide spectrum of contraceptive methods for women, the unintended pregnancy rate remains high (45% in the US), with 50% resulting in abortion. Currently, 20% of global contraceptive use is male-directed, with a wide variation among countries due to limited availability and lack of efficacy. Worldwide studies indicate that >50% of men would opt to use a reversible method, and 90% of women would rely on their partner to use a contraceptive. Additional reasons for novel male contraceptive methods to be available include the increased life expectancy, sharing the reproductive risks among partners, social issues, the lack of pharma industry involvement and the lack of opinion makers advocating for male contraception.

AIM

The present guidelines aim to review the status regarding male contraception, the current state of the art to support the clinical practice, recommend minimal requirements for new male contraceptive development and provide and grade updated, evidence-based recommendations from the European Society of Andrology (EAA) and the American Society of Andrology (ASA).

METHODS

An expert panel of academicians appointed by the EAA and the ASA generated a consensus guideline according to the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system.

RESULTS

Sixty evidence-based and graded recommendations were produced on couple-centered communication, behaviors, barrier methods, semen analysis and contraceptive efficacy, physical agents, surgical methods, actions before initiating male contraception, hormonal methods, non-hormonal methods, vaccines, and social and ethical considerations.

CONCLUSION

As gender roles transform and gender equity is established in relationships, the male contribution to family planning must be facilitated. Efficient and safe male-directed methods must be evaluated and introduced into clinical practice, preferably reversible, either hormonal or non-hormonal. From a future perspective, identifying new hormonal combinations, suitable testicular targets, and emerging vas occlusion methods will produce novel molecules and products for male contraception.

Hormonal male contraception

INTRODUCTION

Male contraception with exogenously administered hormones suppresses both luteinizing hormone and follicle stimulating hormone leading to low intratesticular testosterone concentration. This results in reversible suppression of spermatogenesis and marked decrease in sperm output in the ejaculate and preventing pregnancy in the female partner.

PRIOR STUDIES

Studies of testosterone administered alone or in combination of another gonadotropin suppressive agent such as a progestin or gonadotropin releasing hormone (GnRH) analog showed decisively that the exogenous hormone administrations are effective in suppressing sperm output with few adverse events that are not anticipated. In contraceptive efficacy studies, testosterone alone or combined with a progestin are as effective in preventing pregnancies as female contraceptive methods.

CONCLUSION

Hormone combinations for male contraception are in late-phase clinical trials and hold the promise of being the new, reversible contraception method for men in over half a century. Lessons learned from the male hormonal contraceptive development pave the way for new targeted approached to regulate male fertility.

The landscape of male contraception A narrative review

Reproductive medicine has made significant advancements over the last 70 years, much of it in the way of female contraception. Reliable male contraception continues to be restricted to condoms and vasectomy. The purpose of this narrative review is to provide an overview of the contemporary usage of male contraceptive methods, including ethical and political standpoints, as well as to summarize current and future studies being done on male hormonal and non-hormonal contraceptive options.

Novel Genes of the Male Reproductive System: Potential Roles in Male Reproduction and as Non-hormonal Male Contraceptive Targets

The development of novel non-hormonal male contraceptives represents a pivotal frontier in reproductive health, driven by the need for safe, effective, and reversible contraceptive methods. This comprehensive review explores the genetic underpinnings of male fertility, emphasizing the crucial roles of specific genes and structural variants (SVs) identified through advanced sequencing technologies such as long-read sequencing (LRS). LRS has revolutionized the detection of structural variants and complex genomic regions, offering unprecedented precision and resolution over traditional next-generation sequencing (NGS). Key genetic targets, including those implicated in spermatogenesis and sperm motility, are highlighted, showcasing their potential as non-hormonal contraceptive targets. The review delves into the systematic identification and validation of male reproductive tract-specific genes, utilizing advanced transcriptomics and genomics studies with validation using novel knockout mouse models. We discuss the innovative application of small molecule inhibitors, developed through platforms like DNA-encoded chemistry technology (DEC-Tec), which have shown significant promise in preclinical models. Notable examples include inhibitors targeting serine/threonine kinase 33 (STK33), soluble adenylyl cyclase (sAC), cyclin-dependent kinase 2 (CDK2), and bromodomain testis associated (BRDT), each demonstrating nanomolar affinity and potential for reversible and specific inhibition of male fertility. This review also honors the contributions of Dr. David L. Garbers whose foundational work has paved the way for these advancements. The integration of genomic, proteomic, and chemical biology approaches, supported by interdisciplinary collaboration, is poised to transform male contraceptive development. Future perspectives emphasize the need for continued innovation and rigorous testing to bring these novel contraceptives from the laboratory to clinical application, promising a new era of male reproductive health management.

Identification of the Biotransformation Pathways of a Potential Oral Male Contraceptive, 11β-Methyl-19-Nortestosterone (11β-MNT) and Its Prodrugs: An In Vitro Study Highlights the Contribution of Polymorphic Intestinal UGT2B17

11β-Methyl-19-nortestosterone dodecylcarbonate (11β-MNTDC) is a prodrug of 11β-MNT and is being considered as a promising male oral contraceptive candidate in clinical development. However, the oral administration of 11β-MNTDC exhibits an ~200-fold lower serum concentration of 11β-MNT compared to 11β-MNTDC, resulting in the poor bioavailability of 11β-MNT. To elucidate the role of the first-pass metabolism of 11β-MNT in its poor bioavailability, we determined the biotransformation products of 11β-MNT and its prodrugs in human in vitro models. 11β-MNT and its two prodrugs 11β-MNTDC and 11β-MNT undecanoate (11β-MNTU) were incubated in cryopreserved human hepatocytes (HHs) and subjected to liquid chromatography-high resolution tandem mass spectrometry analysis, which identified ten 11β-MNT biotransformation products with dehydrogenated and glucuronidation (11β-MNTG) metabolites being the major metabolites. However, 11β-MNTG formation is highly variable and prevalent in human intestinal S9 fractions. A reaction phenotyping study of 11β-MNT using thirteen recombinant UDP-glucuronosyltransferase (UGT) enzymes confirmed the major role of UGT2B17 in 11β-MNTG formation. This was further supported by a strong correlation (R2 > 0.78) between 11β-MNTG and UGT2B17 abundance in human intestinal microsomes, human liver microsomes, and HH systems. These results suggest that 11β-MNT and its prodrugs are rapidly metabolized to 11β-MNTG by the highly polymorphic intestinal UGT2B17, which may explain the poor and variable bioavailability of the drug.

Hormone Regulation in Testicular Development and Function

The testes serve as the primary source of androgens and the site of spermatogenesis, with their development and function governed by hormonal actions via endocrine and paracrine pathways. Male fertility hinges on the availability of testosterone, a cornerstone of spermatogenesis, while follicle-stimulating hormone (FSH) signaling is indispensable for the proliferation, differentiation, and proper functioning of Sertoli and germ cells. This review covers the research on how androgens, FSH, and other hormones support processes crucial for male fertility in the testis and reproductive tract. These hormones are regulated by the hypothalamic-pituitary-gonad (HPG) axis, which is either quiescent or activated at different stages of the life course, and the regulation of the axis is crucial for the development and normal function of the male reproductive system. Hormonal imbalances, whether due to genetic predispositions or environmental influences, leading to hypogonadism or hypergonadism, can precipitate reproductive disorders. Investigating the regulatory network and molecular mechanisms involved in testicular development and spermatogenesis is instrumental in developing new therapeutic methods, drugs, and male hormonal contraceptives.

Nonhormonal Male Contraceptive Development-Strategies for Progress

Despite the widely demonstrated public health benefits of contraception, limited contraceptive options are available for men, placing both the contraceptive burden and opportunity solely on women. This review outlines the need for an increased focus on male contraceptive development and highlights several related topics, including the perspectives of women and men on male contraceptives, historical challenges, and reasons behind the persistent delays in male contraceptive development. It also discusses the importance of serendipitous observations in drug discovery and the limitations of depleting sperm or spermatogenic cells as a contraceptive approach. It further provides an overview of ongoing research and development on novel methods, with a goal to offer insights into the multifaceted aspects of nonhormonal male contraceptive development, addressing its implications for the health of men and women. SIGNIFICANCE STATEMENT: Despite well over half a century of effort in developing male contraceptives, there are no approved male contraceptive drugs on the market. This review aims to present strategies for progress in nonhormonal male contraception based on lessons learned from history, with the hope of expediting development and bringing a male contraceptive drug closer to reality.

Novel progestogenic androgens for male contraception: design, synthesis, and activity of C7 α-substituted testosterone†

Male contraceptive development has included use of testosterone (T) with or without a progestin or the use of a single molecule such as progestogenic androgens (PA) for suppression of testicular T production. Expanding upon the vast amount of data accumulated from nortestosterone (NT), NT analogs, and their prodrugs, a new series of PA, the C7 methyl, and ethyl α-substituted T analogs 7α-Methyltestosterone (7α-MT) and 7α-Ethyltestosterone (7α-ET), respectively, were hypothesized and designed to have superior androgenic and progestogenic activities when compared with parent T. Results from androgen receptor and progesterone receptor competitive binding and transcriptional activation assays showed favorable activities for these T analogs. Additionally, 7α-MT and 7α-ET were shown to be active substrates for aromatase in vitro, mitigating a potential negative impact on bone mineral density with long-term use. In conjunction with this observation, the diminished metabolism of these T analogs by 5α-reductase may reduce potential concerns for prostatic growth. In the Hershberger in vivo rat bioassay, 7α-MT and 7α-ET showed superior androgenic and anabolic activities as compared with T. These C7 α-substituted T analogs also showed clear progestogenic activity in the McPhail bioassay which evaluated endometrial glandular arborization in a rabbit model. The discovery of aromatizable molecules with reduced metabolism by 5α-reductase that have androgenic, anabolic, and progestogenic properties indicates that the core and/or prodrugs of 7α-MT and 7α-ET are promising molecules for further development as male contraceptive PAs.

Male contraception: narrative review of ongoing research

BACKGROUND

Since the release of the combined oral contraceptive pill in 1960, women have shouldered the burden of contraception and family planning. Over 60 years later, this is still the case as the only practical, effective contraceptive options available to men are condoms and vasectomy. However, there are now a variety of promising hormonal and non-hormonal male contraceptive options being studied. The purpose of this narrative review is to provide clinicians and laypeople with focused, up-to-date descriptions of novel strategies and targets for male contraception. We include a cautiously optimistic discussion of benefits and potential drawbacks, highlighting several methods in preclinical and clinical stages of development.

RESULTS

As of June 2023, two hormonal male contraceptive methods are undergoing phase II clinical trials for safety and efficacy. A large-scale, international phase IIb trial investigating efficacy of transdermal segesterone acetate (Nestorone) plus testosterone gel has enrolled over 460 couples with completion estimated for late 2024. A second hormonal method, dimethandrolone undecanoate, is in two clinical trials focusing on safety, pharmacodynamics, suppression of spermatogenesis and hormones; the first of these two is estimated for completion in December 2024. There are also several non-hormonal methods with strong potential in preclinical stages of development.

CONCLUSIONS

There exist several hurdles to novel male contraception. Therapeutic development takes decades of time, meticulous work, and financial investment, but with so many strong candidates it is our hope that there will soon be several safe, effective, and reversible contraceptive options available to male patients.

[Male contraception]

CONTEXT

Contraception is a major global health issue, which is still dominated by female contraception. Developments in male contraception could help redistribute the contraceptive burden.

METHODS

A literature search was carried out to review the existing options and the criteria for optimal contraception, to establish the principles of a male pre-contraception consultation, and to review the various research avenues with their advantages and disadvantages.

RESULTS

The new male contraception options are detailed, whether hormonal (androgen therapy, combination of progestins and testosterone) or non-hormonal, particularly thermal, with current results and avenues for improvement. Condom use and vasectomy remain the only 2 validated options. The recent development of minimally invasive vasectomy without the need for a scalpel and of occlusion techniques has simplified the procedure, minimised the risk of complications (pain, haematomas, post-vasectomy pain syndrome) and improved efficacy. The issues of regret and the possibility of repermeabilisation are also raised.

CONCLUSION

The question of male contraception will become increasingly important in consultations with urologists. The urologist will have to inform the patient, as required by law, before the vasectomy is performed, and provide the best possible advice on the technique, which will often be minimally invasive without the need for a scalpel. New reversible options should also broaden the range of options available on a routine basis, with a view to gradually moving towards contraceptive equity.

Male contraception is coming: Who do men want to prescribe their birth control?

OBJECTIVE

To assess men's preferences for healthcare provider from whom they would obtain hormonal male contraceptive (HMC) methods.

STUDY DESIGN

We asked participants from 3 clinical trials of investigational HMC methods-an oral pill (11β-Methyl-19-nortestosterone-17β-dodecylcarbonate, 11β-MNTDC), intramuscular or subcutaneous injection (Dimethandrolone undecanoate), and transdermal gel (Nestorone and testosterone)-to rank their top 3 preferred HMC providers from a list including: men's health doctor (urologist/andrologist), hormonal doctor (endocrinologist), reproductive health doctor (OB/GYN), family planning clinician (community health worker, midwife, nurse practitioner), regular doctor (family medicine/internal medicine), and community pharmacist. We examined preferences based on their rankings and conducted bivariate analyses. Collapsing the various specialists (men's health doctor, hormonal doctor, reproductive health doctor, and family planning clinician) into a single provider type, we examined participant demographics against provider preference (regular doctor, pharmacist, or specialist).

RESULTS

Participants across the 3 trials (n = 124) ranked their regular doctor (44%) and community pharmacist (18%) as their most preferred HMC provider; these preferences did not differ significantly by trial and drug formulation. Specialists in family planning (13%), men's health (12%), reproductive health (10%), and hormones (4%) were least frequently ranked as their preferred provider. Older and higher educated participants more often preferred specialists over regular doctors and pharmacists (p = 0.02 and p = 0.01).

CONCLUSIONS

Despite receiving contraceptive steroid hormones and care from endocrinologists and family planning specialists in a clinical trial, participants would prefer to obtain contraception from their regular doctor.

IMPLICATIONS

As most men expect to obtain hormonal male contraceptives from their regular doctor when commercially available, primary care physicians should become familiar with HMCs and be prepared to provide counseling and options accordingly.

Androgens in male contraception

Rates of unplanned pregnancies are high globally, burdening women and families. Efforts to develop male contraceptive agents have been thwarted by unacceptable failure rates, side effects and a dearth of pharmaceutical industry involvement. Hormonal male contraception consists of exogenous androgens which exert negative feedback on the hypothalamic-pituitary-gonadal axis and suppress gonadotropin production. This in turn suppresses testicular testosterone production and sperm maturation. Addition of a progestin suppresses spermatogenesis more effectively in men. Contraceptive efficacy studies in couples have shown male hormonal methods are effective and reversible, but also may come with side effects related to sexual desire, acne and serum cholesterol and inconvenient methods of dosing and delivery. Recently, novel androgens as potential contraceptive agents are being evaluated in early clinical trials and look to overcome these drawbacks. Here we summarize landmark studies of prototype male hormonal contraceptives, showcasing recent advances and future prospects in this important area of public health.

Hormonal Male Contraception: Getting to Market

Rates of unplanned pregnancies are high and stagnant globally, burdening women, families and the environment. Local limitations placed upon contraceptive access and abortion services exacerbate global disparities for women. Despite survey data suggesting men and their partners are eager for expanded male contraceptive options, efforts to develop such agents have been stymied by a paucity of monetary investment. Modern male hormonal contraception, like female hormonal methods, relies upon exogenous progestins to suppress the hypothalamic-pituitary-gonadal axis, in turn suppressing testicular testosterone production and sperm maturation. Addition of an androgen augments gonadotropin suppression, more effectively suppressing spermatogenesis in men, and provides androgenic support for male physiology. Previous contraceptive efficacy studies in couples have shown that hormonal male methods are effective and reversible. Recent efforts have been directed at addressing potential user and regulatory concerns by utilizing novel steroids and varied routes of hormone delivery. Provision of effective contraceptive options for men and women is an urgent public health need. Recognizing and addressing the gaps in our contraceptive options and engaging men in family planning will help reduce rates of unplanned pregnancies in the coming decades.

Testosterone Replacement Therapy in Hypogonadal Men

All approved testosterone replacement methods, when used according to recommendations, can restore normal serum testosterone concentrations, and relieve symptoms in most hypogonadal men. Selection of the method depends on the patient's preference with advice from the physician. Dose adjustment is possible with most delivery methods but may not be necessary in all hypogonadal men. The use of hepatotoxic androgens must be avoided. Testosterone treatment induces reversible suppression of spermatogenesis; if fertility is desired in the near future, human chronic gonadotropin, selective estrogen receptor modulator, estrogen antagonist, or an aromatase inhibitor that stimulates endogenous testosterone production may be used.

Contraceptive and Infertility Target DataBase: a contraceptive drug development tool for targeting and analysis of human reproductive specific tissues†

The long and challenging drug development process begins with discovery biology for the selection of an appropriate target for a specific indication. Target is a broad term that can be applied to a range of biological entities such as proteins, genes, and ribonucleic acids (RNAs). Although there are numerous databases available for mining biological entities, publicly available searchable, downloadable databases to aid in target selection for a specific disease or indication (e.g., developing contraceptives and infertility treatments) are limited. We report the development of the Contraceptive and Infertility Target DataBase (https://www.citdbase.org), which provides investigators an interface to mine existing transcriptomic and proteomic resources to identify high-quality contraceptive/infertility targets. The development of similar databases is applicable to the identification of targets for other diseases and conditions.

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.

Comparison of metabolic effects of the progestational androgens dimethandrolone undecanoate and 11β-MNTDC in healthy men

BACKGROUND

Dimethandrolone (DMA) and 11β-methyl-19-nortestosterone (11β-MNT) are two novel compounds with both androgenic and progestational activity that are under investigation as potential male hormonal contraceptives. Their metabolic effects have never been compared in men.

OBJECTIVE

Assess for changes in insulin sensitivity and adiponectin and compare the metabolic effects of these two novel androgens.

MATERIALS/METHODS

In two clinical trials of DMA undecanoate (DMAU) and 11β-MNT dodecylcarbonate (11β-MNTDC), oral prodrugs of DMA and 11β-MNT, healthy men received drug, or placebo for 28 days. Insulin and adiponectin assays were performed on stored samples. Mixed model analyses were performed to compare the effects of the two drugs. Student's t test, or the non-parametric Kruskal-Wallis test as appropriate, was used to evaluate for an effect of active drug versus placebo.

RESULTS

Class effects were seen, with decrease in HDL-C and SHBG, and increase in weight and hematocrit, with no statistically significant differences between the two compounds. No changes in fasting glucose, fasting insulin, or HOMA-IR were seen with either compound. There was a slight decrease in adiponectin with DMAU that was not seen with 11β-MNTDC. An increase in LDL-C was seen with 11β-MNTDC but not with DMAU.

DISCUSSION

There were no significant changes in insulin resistance after 28 days of oral administration of these novel androgens despite a mild increase in weight. There may be subtle differences in their metabolic impacts that should be explored in future studies.

CONCLUSION

Changes in metabolic parameters should be carefully monitored when investigating androgenic compounds.

Androgen Treatment in Adolescent Males With Hypogonadism

During adolescence, androgens are responsible for the development of secondary sexual characteristics, pubertal growth, and the anabolic effects on bone and muscle mass. Testosterone is the most abundant testicular androgen, but some effects are mediated by its conversion to the more potent androgen dihydrotestosterone (DHT) or to estradiol. Androgen deficiency, requiring replacement therapy, may occur due to a primary testicular failure or secondary to a hypothalamic–pituitary disorder. A very frequent condition characterized by a late activation of the gonadal axis that may also need androgen treatment is constitutional delay of puberty. Of the several testosterone or DHT formulations commercially available, very few are employed, and none is marketed for its use in adolescents. The most frequently used androgen therapy is based on the intramuscular administration of testosterone enanthate or cypionate every 3 to 4 weeks, with initially low doses. These are progressively increased during several months or years, in order to mimic the physiology of puberty, until adult doses are attained. Scarce experience exists with oral or transdermal formulations. Preparations containing DHT, which are not widely available, are preferred in specific conditions. Oxandrolone, a non-aromatizable drug with higher anabolic than androgenic effects, has been used in adolescents with preserved testosterone production, like Klinefelter syndrome, with positive effects on cardiometabolic health and visual, motor, and psychosocial functions. The usual protocols applied for androgen therapy in boys and adolescents are discussed.

Update on Novel Hormonal and Nonhormonal Male Contraceptive Development

BACKGROUND

The advent of new methods of male contraception would increase contraceptive options for men and women and advance male contraceptive agency. Pharmaceutical R&D for male contraception has been dormant since the 1990s. The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) has supported a contraceptive development program since 1969 and supports most ongoing hormonal male contraceptive development. Nonhormonal methods are in earlier stages of development.

CONTENT

Several hormonal male contraceptive agents have entered clinical trials. Novel single agent products being evaluated include dimethandrolone undecanoate, 11β-methyl-nortestosterone dodecylcarbonate, and 7α-methyl-19-nortestosterone. A contraceptive efficacy trial of Nestorone®/testosterone gel is underway. Potential nonhormonal methods are at preclinical stages of development. Many nonhormonal male contraceptive targets that affect sperm production, sperm function, or sperm transport have been identified.

SUMMARY

NICHD supports development of reversible male contraceptive agents. Other organizations such as the World Health Organization, the Population Council, and the Male Contraception Initiative are pursuing male contraceptive development, but industry involvement remains limited.

Emerging approaches to male contraception

Despite significant interests in contraception by men, effective methods of male contraception are limited to vasectomy and condoms. Recently, there have been several promising advances in male contraceptive research. This review will update readers on recent research in both hormonal and nonhormonal approaches to male contraception. Hormonal approaches to male contraception have been stymied by adverse effects, formulations requiring injections or implants, a 5% to10% nonresponse rate, as well as poor understanding of user acceptability. In the last several years, research has focused on novel, orally bioavailable androgens such as dimethandrolone undecanoate and 11β-methyl-19-nor-testosterone. Additionally, combinations of a topical testosterone gel combined with a gel containing segesterone acetate, a potent progestin, have shown promise in clinical trials recently. Simultaneously, significant preclinical progress has been made in several approaches to nonhormonal male contraceptives, including compounds that inhibit sperm motility such as eppin, compounds that inhibit retinoic acid binding or biosynthesis, and reversible approaches to obstruction of the vas deferens. It is imperative for these areas of research to continue making strides so that there is a gamut of contraceptive options for couples to choose from. Some of these approaches will hopefully reach clinical utility soon, greatly improving contraceptive choice for couples.

Promising results in development of male contraception

Nowadays, conscious planning of the family is very important for many people. The possibility of using protective measures against unplanned pregnancy is a great comfort. Most forms of contraceptives are intended for women, although their use can be ruled out in various health conditions. Scientists have been trying to develop a different type of method for men for many years. More and more research is being done and there have been promising results. It is hoped that soon both genders will have a similar range of contraceptive options to enable responsible family planning.

Male Contraception

Unintended pregnancy is a global public health problem. Despite a variety of female contraceptive options, male contraceptive options are limited to the condom and vasectomy. Condoms have high failure rates and surgical vasectomy is not reliably reversible. There is a global need and desire for novel male contraceptive methods. Hormonal methods have progressed the furthest in clinical development and androgen plus progestin formulations hold promise as a marketable, reversible male contraceptive over the next decade. Investigators have tested androgen plus progestin approaches using oral, transdermal, subdermal, and injectable drug formulations and demonstrated the short-term safety and reversibility of hormonal male contraception. The most commonly reported side effects associated with hormonal male contraception include weight gain, acne, slight suppression of serum high-density cholesterol, mood changes, and changes in libido. Efficacy trials of hormonal male contraceptives have demonstrated contraceptive efficacy rates greater than that of condoms. Although there has been less progression in the development of nonhormonal male contraceptives, potentially reversible vaso-occlusive methods are currently in clinical trials in some countries. Various studies have confirmed both men and women's desire for novel male contraceptives. Barriers to development include an absence of investment from pharmaceutical companies, concerns regarding side effects and spermatogenic rebound with hormonal methods, and lack of clear reversibility and proven effectiveness of nonhormonal methods. The ultimate availability of male contraceptives could have an important impact on decreasing global unintended pregnancy rates (currently 40% of all pregnancies) and will be a step towards reproductive justice and greater equity in family planning.