Testosterone substitution with a new transdermal, hydroalcoholic gel applied to scrotal or non-scrotal skin: a multicentre trial

Efficacy of Nasal Testosterone Gel (Natesto®) Stratified by Baseline Endogenous Testosterone Levels

Objective

Pharmacokinetic and efficacy data from a phase 3 testosterone nasal gel (TNG) study were stratified by baseline endogenous testosterone level in patients with testosterone deficiency. Total testosterone (TT), LH, and FSH levels, as well as erectile function, mood, and lean body mass for each group were compared. In a subset of patients with very low baseline endogenous testosterone levels (<100 ng/dL), we investigated whether TNG is a suitable treatment option.

Materials and Methods

Patients with testosterone deficiency (serum TT <300 ng/dL) were treated with TNG for 3 months, followed by safety extension periods of 90 and/or 180 days. Pharmacokinetic parameters were calculated from serum hormone levels on days 30 and 90, along with efficacy measurements, which were analyzed by comparison with baseline values. Baseline and/or predose TT values were used for patient stratification.

Results

Prestudy and predose endogenous testosterone concentrations correlated. The maximal concentration of TT was nearly identical across all cohorts at days 30 and 90, whereas the average concentration over 24 hours had a slight positive dependence relative to predose levels. LH levels remained in the normal range but were decreased more in patients with higher starting baseline levels. These findings indicate that TNG works with an active hypothalamic-pituitary-gonadal axis that responds to each dose of TNG throughout the treatment period. Patients with the lowest endogenous testosterone levels received maximum exposure impact from each TNG dose. Patients with severe testosterone deficiency had similar efficacy improvements as the remainder of the study population.

Conclusion

All testosterone-deficient cohorts were successfully treated with TNG.

ENDOCRINE HISTORY: The history of discovery, synthesis and development of testosterone for clinical use

As the most important male hormone, testosterone has an impact on almost all organs and body functions. The biological effects of testosterone and the testes have been known since antiquity, long before testosterone was identified as the active agent. Practical applications of this knowledge were castration of males to produce obedient servants, for punishment, for preservation of the prepubertal soprano voice and even for treatment of diseases. Testes were used in organotherapy and transplanted as treatment for symptoms of hypogonadism on a large scale, although these practices had only placebo effects. In reaction to such malpractice in the first half of the 20th century science and the young pharmaceutical industry initiated the search for the male hormone. After several detours together with their teams in 1935, Ernst Laqueur (Amsterdam) isolated and Adolf Butenandt (Gdansk) as well as Leopold Ruzicka (Zürich) synthesized testosterone. Since then testosterone has been available for clinical use. However, when given orally, testosterone is inactivated in the liver, so that parenteral forms of administration or modifications of the molecule had to be found. Over 85 years the testosterone preparations have been slowly improved so that now physiological serum levels can be achieved.

The My-T study: Patient satisfaction and preference comparing topical and nasal testosterone therapies

INTRODUCTION

Natesto^®, testosterone nasal gel (TNG) is an intranasal testosterone therapy (TTh) used to restore testosterone levels and improve symptoms of hypogonadism. Treatment requires application two (bid) or three (tid) times daily. The Treatment Satisfaction Questionnaire for Medication (TSQM) and a Patient Preference and Use (PPU) Questionnaire were used to obtain patient feedback on the use of TNG and compare to experience with topical TTh.

METHODS

The study enrolled 24 TTh-naive (TThN) and 93 TTh-experienced (TThE) hypogonadal men. Treatment lasted up to 120 days, with titration at day 90 to determine the most appropriate dose for restoration of testosterone levels (11 mg bid or tid). Patient satisfaction and symptom changes were measured at days 0, 30, 60, 90, and 120. The PPU Questionnaire was performed at study entry and study completion.

RESULTS

Symptoms improved from baseline (30.6) to day 90 (35.1) (p<0.0001; +15%), consistent with testosterone replacement. TNG increased scores for effectiveness (+20%), convenience (+30%), and global satisfaction (+3%) as compared to their previous topical TTh. TThE patients reported ease of use, convenience, efficacy/effectiveness, and travel friendliness as "likes" of TNG therapy. Overall, 67.2% of patients agreed or strongly agreed that they preferred TNG over topical TTh and 59% sought a prescription to continue treatment with TNG.

CONCLUSIONS

Patients switching from topical TTh to TNG reported significant improvements in symptoms and patient satisfaction compared to their previous topical TTh. Patients also reported a significant improvement in convenience with TNG despite two to three times daily application. Preference, satisfaction, and convenience may translate to better treatment compliance.

The efficacy and safety of short-acting testosterone ointment (Glowmin) for late-onset hypogonadism in accordance with testosterone circadian rhythm

INTRODUCTION

It is well known that there is a reduction of circadian rhythm in blood testosterone levels with aging. Our previous report revealed that 3 mg of short-acting testosterone ointment (Glowmin: GL) elevated serum testosterone levels to within the physiological range for 4-6 h. The aim of this study was to clarify the clinical efficacy and safety of GL used topically once every morning, to enhance the circadian rhythm of testosterone, for late-onset hypogonadism (LOH).

METHODS

A total of 61 LOH patients received 3 mg of GL topically once a day in the morning on scrotal skin for 24 weeks. The clinical efficacy of GL was evaluated by the aging males symptoms (AMS) scale, and blood sampling tests were measured before and after GL treatment.

RESULTS

Mean patients age was 55.3 ± 9.2 years old. Total AMS scores at 4, 12, and 24 weeks after GL treatments significantly decreased. The results of sub-analysis of AMS, including psychological, physical, and sexual factors also significantly improved after GL treatments. No severe adverse reactions or abnormal laboratory data were reported.

CONCLUSIONS

This study shows that TRT for LOH with once daily GL treatment supports testosterone circadian rhythm and should be considered to be an effective and safe therapy for LOH.

Emerging medication for the treatment of male hypogonadism

INTRODUCTION

Male hypogonadism is characterized by inadequate production of Testosterone (T) (hypoandrogenism) and deficiencies in spermatogenesis. The main treatment of male hypogonadism is T replacement therapy (TRT), but for some of the patients, alternative drugs may be more suitable.

AREAS COVERED

The available literature of T and alternative treatments for male hypogonadism are discussed.

EXPERT OPINION

Transdermal application of T gels are the most commonly used route of T administration. Some oral T formulations are either associated with hepatic toxicity (i.e. methyltestosterone) or short half-lives that require multiple doses per day (i.e. oral testosterone undecanoate). Short acting, injectable T formulations are also available. If the patient prefers not to use daily drugs or short acting injectable formulations, depot formulations such as injectable testosterone undecanoate (TU) may be a good alternative. If the patient has hypogonadotropic hypogonadism and desires fertility or if he is adolescent, instead of TRT, gonadotropins can be started to stimulate testicular growth and spermatogenesis. In obese patients or for the patients having high risks for TRT, off label aromatase inhibitors (AI) and clomiphene citrate (CC), may be considered to stimulate LH, FSH and T levels. In patients with high prostate disease risk, selective androgen receptor modulators may be an alternative treatment but these latter treatments have not had high level evidence.

Treatment of Hypogonadism: Current and Future Therapies

The treatment of hypogonadism in men is of great interest to both patients and providers. There are a number of testosterone formulations currently available and several additional formulations under development. In addition, there are some lesser-used alternative therapies for the management of male hypogonadism, which may have advantages for certain patient groups. The future of hypogonadism therapy may lie in the development of selective androgen receptor modulators that allow the benefits of androgens whilst minimizing unwanted side effects.

Current topics in testosterone replacement of hypogonadal men

All forms of hypogonadism - primary, secondary and late-onset - require testosterone substitution. The indication is given when the patient presents with symptoms of androgen deficiency and the serum testosterone levels are below normal. Several testosterone preparations and modes of application are available of which those producing physiologic serum levels should be preferred e.g. preferentially transdermal gels and long-acting intramuscular testosterone undecanoate. Testosterone substitution must be monitored at regular intervals, best at 3, 6 and 12 months after initiation and then annually. Parameters for surveillance include well-being, libido and sexual activity, measurement of serum testosterone levels, haemoglobin and haematocrit, PSA and digital rectal examination, and, biannually, bone mineral density. Testosterone has positive effects on comorbidities such as obesity, metabolic syndrome, diabetes type II, cardiovascular diseases and osteoporosis.

Testosterone deficiency: a historical perspective

The biological effects of the testes and testosterone are known since antiquity. Aristotle knew the effects of castration and his hypothesis on fertilization is one of the first scientific encounters in reproductive biology. Over centuries, castration has been performed as punishment and to produce obedient slaves, but also to preserve the soprano voices of prepubertal boys. The Chinese imperial (and other oriental) courts employed castrates as overseers in harems who often obtained high-ranking political positions. The era of testis transplantation and organotherapy was initiated by John Hunter in London who transplanted testes into capons in 1786. The intention of his experiments was to prove the 'vital principle' as the basis for modern transplantation medicine, but Hunter did not consider endocrine aspects. Arnold Adolph Berthold postulated internal secretion from his testicular transplantation experiments in 1849 in Göttingen and is thus considered the father of endocrinology. Following his observations, testicular preparations were used for therapy, popularized by self-experiments by Charles-Edouard Brown-Séquard in Paris (1889), which can at best have placebo effects. In the 1920s Sergio Voronoff transplanted testes from animals to men, but their effectiveness was disproved. Today testicular transplantation is being refined by stem cell research and germ cell transplantation. Modern androgen therapy started in 1935 when Enrest Lacquer isolated testosterone from bull testes in Amsterdam. In the same year testosterone was chemically synthesized independently by Adolf Butenandt in Göttingen and Leopold Ruzicka in Basel. Since testosterone was ineffective orally it was either compressed into subcutaneous pellets or was used orally as 17α-methyl testosterone, now obsolete because of liver toxicity. The early phases of testosterone treatment coincide with the first description of the most prominent syndromes of hypogonadism by Klinefelter, by Kallmann, DelCastillo and Pasqualini. In the 1950s longer-acting injectable testosterone enanthate became the preferred therapeutic modality. In the 1950s and 1960s, research concentrated on the chemical modification of androgens in order to emphasize their anabolic effects. Although anabolic steroids have largely disappeared from clinical medicine, they continue to live an illegal life for doping in athletics. In the 1970s the orally effective testosterone undecanoate was added to the spectrum of preparations. Recent transdermal gels and long-acting injectable preparations provide options for physiological testosterone substitution therapy.

Klinefelter syndrome: the commonest form of hypogonadism, but often overlooked or untreated

BACKGROUND

Klinefelter syndrome (KS) with the karyotype 47,XXY is one of the commonest types of congenital chromosomal disorder in males, with an incidence of 0.1% to 0.2% of newborn male infants. It causes hypogonadism and infertility. Until now, however, only about one-quarter of all persons with KS received the diagnosis during their lifetimes.

METHODS

Selective review of the literature.

RESULTS

KS is caused by aneuploidy of the sex chromosomes. Small, firm testes, the manifestations of androgen deficiency (sparse development of male-pattern body hair, greater than average height, lack of libido, erectile dysfunction) and, in more than 90% of affected men, azoospermia are its main features in adults. Affected boys may have verbalization difficulties and problems with learning and socialization. KS is often accompanied by other disturbances such as gynecomastia, varicose veins, thrombosis, osteoporosis, the metabolic syndrome, type 2 diabetes, and epilepsy. The most important therapeutic measure is testosterone supplementation, which should be initiated if the testosterone concentration drops below 12 nmol/L and should be given as directed in the guidelines for the treatment of hypogonadism. This recommendation is made even though there have not been any randomized controlled trials documenting the efficacy of testosterone therapy in adolescents or young adults. In some cases, viable sperm can be obtained from individual testicular tubules by biopsy, so that these patients are able to become fathers.

CONCLUSION

The diagnosis of KS would be less frequently missed if doctors were more aware of, and attentive to, its key manifestations, particularly the small, firm testes, erectile dysfunction, and the comorbidities mentioned above. If the diagnosis were made more often, patients would more often be able to receive early treatment, which would improve their quality of life.

Late-life onset hypogonadism: a review

Increased longevity and population aging will increase the number of men with late-onset hypogonadism, a common condition that is often under diagnosed and under treated. The indication of testosterone replacement therapy (TRT) treatment requires the presence of low testosterone level and symptoms and signs of hypogonadism. Although there is a lack of large-scale, long-term studies assessing the benefits and risks of TRT in men with hypogonadism, reports indicate that TRT may produce a wide range of benefits that include improvement in libido and sexual function, bone density, muscle mass, body composition, mood, erythropoiesis, cognition, quality of life, and cardiovascular disease. Perhaps the most controversial area is the issue of risk, especially the possible stimulation of prostate cancer by testosterone, even though there is no evidence to support this risk. Other possible risks include worsening symptoms of benign prostatic hypertrophy, liver toxicity, hyperviscosity, erythrocytosis, worsening untreated sleep apnea, or severe heart failure. Despite this controversy, testosterone supplementation in the United States has increased substantially in the past several years. The physician should discuss with the patient the potential benefits and risks of TRT. This review discusses the benefits and risks of TRT.

Safety and efficacy of testosterone gel in the treatment of male hypogonadism

Transdermal testosterone gels were first introduced in the US in 2000. Since then, they have emerged as a favorable mode of testosterone substitution. Serum testosterone levels reach a steady-state in the first 24 hours of application and remain in the normal range for the duration of the application. This pharmacokinetic profile is comparable to that of testosterone patch but superior to injectable testosterone esters that are associated with peaks and troughs with each dose. Testosterone gels are as efficacious as patches and injectable forms in their effects on sexual function and mood. Anticipated increases in prostate-specific antigen with testosterone therapy are not significantly different with testosterone gels, and the risk of polycythemia is lower than injectable modalities. Application site reactions, a major drawback of testosterone patches, occur less frequently with testosterone gels. However, inter-personal transfer is a concern if appropriate precautions are not taken. Superior tolerability and dose flexibility make testosterone gel highly desirable over other modalities of testosterone replacement. Androgel and Testim, the two currently available testosterone gel products in the US, have certain brand-specific properties that clinicians may consider prior to prescribing.

The benefits and risks of testosterone replacement therapy: a review

Increased longevity and population aging will increase the number of men with late onset hypogonadism. It is a common condition, but often underdiagnosed and undertreated. The indication of testosterone-replacement therapy (TRT) treatment requires the presence of low testosterone level, and symptoms and signs of hypogonadism. Although controversy remains regarding indications for testosterone supplementation in aging men due to lack of large-scale, long-term studies assessing the benefits and risks of testosterone-replacement therapy in men, reports indicate that TRT may produce a wide range of benefits for men with hypogonadism that include improvement in libido and sexual function, bone density, muscle mass, body composition, mood, erythropoiesis, cognition, quality of life and cardiovascular disease. Perhaps the most controversial area is the issue of risk, especially possible stimulation of prostate cancer by testosterone, even though no evidence to support this risk exists. Other possible risks include worsening symptoms of benign prostatic hypertrophy, liver toxicity, hyperviscosity, erythrocytosis, worsening untreated sleep apnea or severe heart failure. Despite this controversy, testosterone supplementation in the United States has increased substantially over the past several years. The physician should discuss with the patient the potential benefits and risks of TRT. The purpose of this review is to discuss what is known and not known regarding the benefits and risks of TRT.

Testosterone therapy in the aging male

The decline, with aging, in serum concentrations of biologically active forms of testosterone in men is an indisputable fact and some men will eventually develop symptoms of late-onset hypogonadism (LOH) with its clinical consequences. LOH reduces quality of life and may pose important risk factors for frailty, changes in body composition, cardiovascular disease, sexual dysfunction and osteoporosis. Testosterone supplementation in cases of LOH will restore serum testosterone levels into the physiologic range; will restore metabolic parameters to the eugonadal state, increase muscle mass, strength, and function; maintaine or improve BMD reducing fracture risk; will improve neuropsychological function (cognition and mood); libido and sexual functioning; and enhance quality of life. The ultimate goals, however, are to maintain or regain a high quality of life, to reduce disability, to compress major illnesses into a narrow age range and to add life to years. To achieve these goals men must also adjust their lifestyle to optimize dietary habits, as well as to exercise and to abstain from smoking life-long. Monitoring these patients is a shared responsibility that cannot be taken lightly. The physician must emphasize to the patient the need for periodic evaluations and the patient must agree to comply with these requirements. The physician's evaluation should include an assessment of the clinical response and monitoring must be tailored to the indications and individual needs of the patient.

Testosterone treatment to mimic hormone physiology in androgen replacement therapy. A view on testosterone gel and other preparations available

There is still considerable controversy concerning the issue of testosterone replacement therapy. This is because testosterone replacement therapy is not a 'risk-free' treatment and a randomized controlled trial to evaluate safety of prolonged testosterone replacement therapy is not available, nor is it likely to be in the near future. However, recent testosterone delivery systems, such as the 1% gel (Testogel, Androgel and Testim), have proven to have a good physiologic profile, allowing constant monitoring of the possible complications and prompt discontinuation in the event of adverse effects. The aim of this paper is to provide a comprehensive review of the available testosterone preparations to treat male hypogonadism, with special interest in the treatment of ageing men and late-onset hypogonadism. In addition, the experimental and clinical data on the effect of testosterone on sexual function domains is reviewed along with the indication for the combination therapy of androgens with pro-erectile drugs, for example, type 5 phosphodiesterase inhibitors.

Testosterone replacement therapy and prostate cancer: A word of caution

The number of men for whom testosterone is prescribed is rapidly increasing. The aging man normally demonstrates a gradual decline in testosterone. Symptoms of hypogonadism include erectile dysfunction, diminished libido, sarcopenia, increased adiposity, osteopenia and osteoporosis, impaired cognition, and depression. There is a paucity of data regarding both efficacy and safety of testosterone replacement therapy. Testosterone levels have been shown to modulate prostate cancer risk and progression. A prospective evaluation of prostate cancer risk with testosterone replacement therapy has not been conducted. We outline concerns and recommendations for the use of testosterone replacement therapy in the aging man.

Testosterone and ageing: what have we learned since the Institute of Medicine report and what lies ahead?

A 2003 report by the Institute of Medicine (IOM) surveyed the literature on the benefits and risks of testosterone replacement therapy in older men and identified knowledge gaps and research needs. This review summarises some key studies published since the IOM report. The possible relationship of testosterone to risk of prostate cancer remains a concern; however, no new evidence has emerged to suggest that testosterone replacement therapy increases the risk. Recent studies have demonstrated that hypogonadism in men may be more prevalent than previously thought, is strongly associated with metabolic syndrome, and may be a risk factor for type 2 diabetes and cardiovascular disease. Clinical studies have shown that testosterone replacement therapy in hypogonadal men improves metabolic syndrome indicators and cardiovascular risk factors. Maintaining testosterone concentrations in the normal range has been shown to contribute to bone health, lean muscle mass, and physical and sexual function, suggesting that testosterone replacement therapy may help to prevent frailty in older men. Based on current knowledge, testosterone replacement therapy is unlikely to pose major health risks in patients without prostate cancer and may offer substantial health benefits. Larger, longer-term randomised studies are needed to fully establish the effects of testosterone replacement therapy.

Emerging drugs for hypogonadism

Male hypogonadism is a common endocrine problem that affects men of all ages. Recently, there has been a surge in testosterone use among middle-aged and older men who in the past may have been considered to have borderline or even normal testosterone levels. This increasing use of testosterone therapy among men has paralleled the increasing improvements in the development of treatments for male hypogonadism that have been made over the past few decades. Current therapies using transdermal formulations and long-acting injectables such as testosterone undecanoate are quickly replacing the old injectable testosterone esters. In recent years, pharmaceutical sales and prescription data have readily shown a shift in the testosterone marketplace towards greater use of slightly more expensive treatments such as transdermal therapies, which are easier to administer and yield more physiological levels of testosterone. On the horizon are several new compounds in development, such as selective androgen receptor modulators (SARMS), 7alpha-methyl-19-nortestosterone, aromatase inhibitors, clomifene, dihydrotestosterone and human chorionic gonadotropin. Compounds such as SARMs are designed to selectively target androgen receptors in specific tissues (such as bone and muscles), in the hope of dispersing some of the side effects experienced on the prostate, which are presently associated with therapy of exogenous testosterone.

Testosterone treatment comes of age: new options for hypogonadal men

Male hypogonadism is one of the most frequent, but also most underdiagnosed, endocrinopathies. However, the required testosterone treatment is simple and very effective if properly administered. Although testosterone has been available for clinical use for seven decades, until quite recently the treatment modalities were far from ideal. Subdermal testosterone pellets require minor surgery for insertion and often cause local problems. The injectable testosterone enanthate, for a long period the most frequently used mode of administration, lasts for two to four weeks, but produces supraphysiological levels initially and low levels before the next injection. The oral testosterone undecanoate has to be taken three times daily, has an uncertain absorption pattern and results in peaks and valleys of serum testosterone levels throughout the day. With the advent of transdermal testosterone preparations, the desired physiological serum levels could be achieved for the first time. Scrotal testosterone patches were the first to fulfil this requirement. These were followed by nonscrotal skin patches, which, however, cause considerable skin reactions including erythema and blisters. Recently introduced, invisible transdermal testosterone gels increased the intervals of application and are now slowly replacing other modalities. A mucoadhesive buccal testosterone tablet with sustained release is also a recent competing modality. Finally, injectable testosterone undecanoate in castor oil was made into a real depot preparation requiring only four injections per year for replacement therapy. These new preparations with a desired pharmacokinetic testosterone profile give the patient a real choice and make treatment easier. Based on pharmacogenetic considerations taking the androgen receptor polymorphism into account, treatment may be individualized for each patient in the future.