An analysis of testosterone implants for androgen replacement therapy

Testosterone Pellet Use in Transgender Men

Purpose

We assessed the efficacy and short-term adverse effects of testosterone pellet use in transgender men to broaden therapeutic options.

Methods

We conducted a retrospective study of 30 transgender men who started testosterone pellets between 2018 and 2020.

Results

Testosterone pellets were started at dosages 675-825 mg per cycle and dose was adjusted according to testosterone levels obtained 1 to 6 months post-testosterone pellet insertion. Pharmacokinetics of testosterone pellet in transgender men was similar to those in cisgender men. Total testosterone levels reached a peak in 1 month and remained in the therapeutic range for ∼4 months in the range of 300-800 ng/dL. After switching over to testosterone pellets, 100% of patients continued to achieve amenorrhea and deepening of their voice. Most of the patients noticed increased hair growth in androgen-dependent regions (96.3%) and improved libido (70%). Adverse events were notable for a rate of polycythemia that was unexpectedly high at 46.67%. Pellet extrusion was found in 13.33% of patients. There was a low rate of pellet site hematoma (6.67%) and cellulitis (3.33%). No thromboembolic or cardiovascular events occurred in any of the patients.

Conclusion

This study reveals that testosterone pellets are a reasonable alternative to other testosterone modalities in transgender men but would use caution in patients with a history of polycythemia or higher risk for thromboembolic events.

Long vs Short Acting Testosterone Treatments: A Look at the Risks

Prescriptions for testosterone therapy (TT) to treat testosterone deficiency have increased in recent years. The purpose of this review was to evaluate the risks of several treatment modalities to better counsel patients. Both short-acting and long-acting TT has been shown to restore normal serum testosterone levels and improve symptoms of testosterone deficiency. Short-acting pharmacology mimics normal physiology more closely than long-acting TT but requires multiple doses per day. Long-acting TT has a higher rate of patient adherence but is more likely to create supraphysiologic serum testosterone and pathologic sequelae.

An Individualized Approach to Managing Testosterone Therapy in the Primary Care Setting

The incidence of testosterone deficiency and the use of testosterone therapy have increased in recent years, and currently the majority of testosterone prescriptions in the United States and Canada are written by primary care physicians. Meanwhile, the range of available testosterone therapy formulations has widened to include buccal tablets, intramuscular injections, transdermal gels, intranasal gel, subcutaneous injections, oral capsules, and subdermal pellets, each with unique pharmacokinetic and clinical characteristics. Despite the growing use of testosterone therapy and its overall efficacy and safety as demonstrated in clinical trials, concerns exist about the potential impact of testosterone therapy on spermatogenesis and fertility, development of prostate cancer, and risk of polycythemia and cardiovascular events. In addition, ongoing research aims to better characterize the effects of testosterone therapy in specific populations, such as patients aged 65 years and older, patients with obesity and type 2 diabetes, and transgender patients. The range of treatment options and the diversity of patients' goals, preferences, comorbidities, and risk factors necessitate an individualized approach to testosterone therapy that considers each patient's clinical needs alongside the distinct features of different testosterone formulations.

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.

Long-Acting Injection and Implant Preferences and Trade-Offs for HIV Prevention Among South African Male Youth

BACKGROUND

Long-acting pre-exposure prophylaxis (LA-PrEP) formulated as implants and injections are promising prevention method strategies offering simplicity, discretion, and long dose duration. Men are important end users of LA-PrEP, and early assessment of their preferences could enhance downstream male engagement in HIV prevention.

METHODS

A discrete-choice experiment survey was conducted with 406 men, aged 18-24, in Cape Town, South Africa, to assess preferences for 5 LA-PrEP attributes with 2-4 pictorially-depicted levels: delivery form, duration, insertion location, soreness, and delivery facility. Latent class analysis was used to explore heterogeneity of preferences and estimate preference shares.

RESULTS

The median age was 21 (interquartile range 19-22), and 47% were men who have sex with men. Duration was the most important product attribute. Latent class analysis identified 3 classes: "duration-dominant decision makers" (46%) were the largest class, defined by significant preference for a longer duration product. "Comprehensive decision makers" (36%) had preferences shaped equally by multiple attributes and preferred implants. "Injection-dominant decision makers" (18%) had strong preference for injections (vs. implant) and were significantly more likely to be men who have sex with men. When estimating shares for a 2-month injection in the buttocks with mild soreness (HPTN regimen) vs. a 6-month implant (to arm) with moderate soreness (current target), 95% of "injection-dominant decision makers" would choose injections, whereas 79% and 63% of "duration-dominant decision makers" and "comprehensive decision makers" would choose implant.

CONCLUSIONS

Young South African men indicated acceptability for LA-PrEP. Preferences were shaped mainly by duration, suggesting a sizeable market for implants, and underscoring the importance of product choice. Further research into men's acceptability of LA PrEP strategies to achieve engagement in these HIV prevention tools constitutes a priority.

An update on the available and emerging pharmacotherapy for adults with testosterone deficiency available in the USA

Introduction: Testosterone deficiency (TD) is defined as low serum testosterone associated with symptoms and signs. There has been an increasing prevalence of TD in recent decades, especially in males aged 15-39. Many of these men will require long-term testosterone therapy (TT). Although the end-goals for all treatments are essentially the same, strategies for increasing serum testosterone should be decided individually.Areas covered: This review focuses on the pharmacological management of TD in adults which includes TT with different routes of administration, such as transdermal, buccal, intramuscular and subcutaneous injections, pellets, nasal gel, and oral (pills). The authors review the options for TT available in the USA with emphasis on newer therapies. Furthermore, they examine the efficacy of these therapies with comparison between potential advantages or disadvantages related to dosing, administration method, and adverse events.Expert opinion: Treating TD can be difficult due to the wide range of available medications, diverse side effects related to testosterone replacement and route-of-administration, and necessity for long-term therapy. The combination of pharmacological and non-pharmacological therapies can improve symptoms of TD and patient satisfaction. Each patient should be managed individually, and clinicians should consider available treatment regimens based on the route-of-administration, efficacy, safety, and cost based on a shared decision-making approach.

Novel double-layer Silastic testicular prosthesis with controlled release of testosterone in vitro, and its effects on castrated rats

Testicular prostheses have been used to deal with anorchia for nearly 80 years. Here, we evaluated a novel testicular prosthesis that can controllably release hormones to maintain physiological levels of testosterone in vivo for a long time. Silastic testicular prostheses with controlled release of testosterone (STPT) with different dosages of testosterone undecanoate (TU) were prepared and implanted into castrated Sprague-Dawley rats. TU oil was applied by oral administration to a separate group of castrated rats. Castrated untreated and sham-operated groups were used as controls. Serum samples from every group were collected to measure the levels of testosterone (T), follicle-stimulating hormone and luteinizing hormone (LH). Maximum intracavernous penile pressure (ICPmax) was recorded. The prostates and seminal vesicles were weighed and subjected to histology, and a terminal dexynucleotidyl transferase-mediated UTP nick end labeling (TUNEL) assay was used to evaluate apoptosis. Our results revealed that the weights of these tissues and the levels of T and LH showed significant statistical differences in the oral administration and TU replacement groups compared with the castrated group (P < 0.05). Compared with the sham-operated group, the ICPmax, histology and TUNEL staining for apoptosis, showed no significant differences in the hormone replacement groups implanted with medium and high doses of STPT. Our results suggested that this new STPT could release TU stably through its double semi-permeable membranes with excellent biocompatibility. The study provides a new approach for testosterone replacement therapy.

Testosterone Pellet Associated Dermatitis: Report and Review of Testopel-related Cutaneous Adverse Effects

Testosterone replacement therapy is a treatment utilized for male hypogonadism. A subcutaneous testosterone pellet is a long-acting, slow-release delivery system that can be utilized as androgen replacement therapy. A 77-year-old man who was treated with testosterone pellets developed dermatitis consisting of erythematous plaques and patches on both buttocks and thighs within 28 days following the subcutaneous insertion of testosterone pellets. The skin lesions rapidly resolved with high-potency topical corticosteroid application. The same cutaneous eruption occurred with each subsequent insertion of testosterone pellets. Other cutaneous adverse events associated with testosterone pellet insertion include acne, hirsutism, and male pattern alopecia. Bleeding, bruising, fibrosis, infections, pellet extrusion, scarring, and subcutaneous nodules may also occur at the injection site. In summary, testosterone pellet-induced dermatitis is a rare adverse cutaneous event, which should be added to the list of potential testosterone pellet associated skin side effects.

The current state of male hormonal contraception

World population continues to grow at an unprecedented rate, doubling in a mere 50years to surpass the 7-billion milestone in 2011. This steep population growth exerts enormous pressure on the global environment. Despite the availability of numerous contraceptive choices for women, approximately half of all pregnancies are unintended and at least half of those are unwanted. Such statistics suggest that there is still a gap in contraceptive options for couples, particularly effective reversible contraceptives for men, who have few contraceptive choices. Male hormonal contraception has been an active area of research for almost 50years. The fundamental concept involves the use of exogenous hormones to suppress endogenous production of gonadotropins, testosterone, and downstream spermatogenesis. Testosterone-alone regimens are effective in many men but high dosing requirements and sub-optimal gonadotropin suppression in 10-30% of men limit their use. A number of novel combinations of testosterone and progestins have been shown to be more efficacious but still require further refinement in delivery systems and a clearer understanding of the potential short- and long-term side effects. Recently, synthetic androgens with both androgenic and progestogenic activity have been developed. These agents have the potential to be single-agent male hormonal contraceptives. Early studies of these compounds are encouraging and there is reason for optimism that these may provide safe, reversible, and reliable contraception for men in the near future.

A Review of Testosterone Pellets in the Treatment of Hypogonadism

Currently, the most popular form of testosterone replacement is the topical gels that require daily applications and incur a risk of transfer of testosterone to partners and family. One of the problems with testosterone replacement is the short half-life of testosterone. A long-acting formulation is appealing to patients and physicians. In 1972, fused crystalline testosterone pellets were approved in the USA by the FDA but they were not marketed until 2008. Pharmacokinetics studies were available on a different formulation from which much can be learned and applied to the current formulation, Testopel®. The decay kinetics, pituitary suppression, and effect on other sex steroids are reviewed as well as the short-term complication rates. This review should provide the testosterone pellet implanter a better understanding of the physiology of testosterone pellet supplementation for hypogonadism.

Pharmacokinetic-pharmacodynamic study of subcutaneous injection of depot nandrolone decanoate using dried blood spots sampling coupled with ultrapressure liquid chromatography tandem mass spectrometry assays

CONTEXT

Testosterone (T) and nandrolone (N) esters require deep im injections by medical personnel but these often deposit injectate into sc fat so that more convenient sc self-administration may be feasible.

OBJECTIVE

To investigate the feasibility and pharmacology of sc injection of N decanoate in healthy men using dried blood spot (DBS) for frequent blood sampling without clinic visits.

SETTING AND DESIGN

Healthy male volunteers received 100 mg N decanoate by a single sc injection. Finger-prick capillary blood was spotted onto filter paper before injection daily at home for 21 d and stored at room temperature. Venous whole blood was also spotted onto filter paper before and weekly for 3 wk after injection. DBS were extracted for assay of N and T by liquid chromatography tandem mass spectrometry in a single batch with serum concentrations estimated with adjustment for capillary blood sample volume and hematocrit to define peak (N) or nadir (T) time and concentration from individual daily measurements.

RESULTS

Daily serum N peaked 2.50 ± 0.25 (SEM) ng/mL at a median (range) of 6 (4-13) days causing a reduction in serum T from 3.50 ± 0.57 ng/mL at baseline to a nadir of 0.38 ± 0.13 (SEM) ng/mL (89 ± 3% suppression) at a median (range) of 8 (5-16) days. Simultaneously sampled capillary, venous whole blood, and serum gave almost identical results for serum T and N. Finger-pricks and sc injections were well tolerated.

CONCLUSIONS

This study demonstrates that A) DBS sampling with liquid chromatography mass spectrometry steroid analysis achieves frequent time sampling in the community without requiring clinic visits, venesection, or frozen serum storage, and B) androgen esters in an oil vehicle can be delivered effectively by sc injection, thus avoiding the need for medically supervised deep-im injections.

Topical testosterone supplementation for the treatment of male hypogonadism

Age-related hormonal decline is gradual and less recognized in men than in women. Symptoms are oftentimes ignored and non-specific. Fatigue, lack of concentration, mood swings, decreased sexual desire, erectile dysfunction, infertility, hair loss, reduced muscle and bone mass, and weight gain are a few of the symptoms of male hypogonadism. This disorder is linked to reduction in quality of life, and poorer health outcomes as it may increase the risk for cardiovascular disease, diabetes mellitus, metabolic syndrome, Alzheimer's disease and premature death. Different modalities of testosterone replacement therapy have evolved over 70 years, and sales continue to grow. Each preparation is differentiated by route of delivery, ease of use, cost and pharmacokinetics. Topical/transdermal testosterone replacement therapy, including patches and gels, are the most modern formulations on the market. These are more expensive treatments, but yield more physiological concentrations of testosterone. Restoration of testosterone levels to the eugonadal range reverses signs and symptoms of hypogonadism, except for infertility, and may alleviate co-morbidities associated with hypogonadism. Patient understanding of and compliance with both treatment and monitoring are of utmost importance to achieve clinical success with maximum benefit and minimum risk. The aim of our review is to summarize the indications, contraindications, benefits and risks of testosterone replacement therapy as they relate to transdermal administration. Further, we compare the various testosterone preparations, focusing on the newest topical/transdermal routes of administration that are currently available.

Is testosterone treatment good for the prostate? Study of safety during long-term treatment

INTRODUCTION

For men with androgen deficiency on testosterone replacement therapy (TRT), clinical concern relates to the development of prostate cancer (PCa).

AIM

An updated audit of prostate safety from the UK Androgen Study was carried out to analyze the incidence of PCa during long-term TRT.

MAIN OUTCOME MEASURES

Diagnosis of PCa in men receiving TRT, by serum prostate-specific antigen (PSA) testing and digital rectal examination (DRE), and its relation to different testosterone preparations.

METHODS

One thousand three hundred sixty-five men aged 28-87 (mean 55) years with symptomatic androgen deficiency and receiving TRT have been monitored for up to 20 years. All patients were prescreened for PCa by DRE and PSA along with endocrine, biochemical, hematological, and urinary profiles at baseline and every 6 months. Abnormal findings or rising PSA were investigated by transrectal ultrasound and prostate biopsy. The data were compared for the four different testosterone preparations used in TRT, including pellet implants, Restandol, mesterolone, and Testogel.

RESULTS

Fourteen new cases of PCa were diagnosed at one case per 212 years treatment, after 2,966 man-years of treatment (one case per 212 years). Time to diagnosis ranged from 1 to 12 years (mean 6.3 years). All tumors were clinically localized and suitable for potentially curative treatment. Initiating testosterone treatment had no statistically significant effect on total PSA, free PSA or free/total PSA ratio, and any initial PSA change had no predictive relationship to subsequent diagnosis of cancer.

CONCLUSIONS

The incidence of PCa during long-term TRT was equivalent to that expected in the general population. This study adds to the considerable weight of evidence that with proper clinical monitoring, testosterone treatment is safe for the prostate and improves early detection of PCa. Testosterone treatment with regular monitoring of the prostate may be safer for the individual than any alternative without surveillance.

Intranasal administration of testosterone increased immobile-sniffing, exploratory behavior, motor behavior and grooming behavior in rats

Currently, testosterone (T) replacement therapy is typically provided by oral medication, injectable T esters, surgically implanted T pellets, transdermal patches and gels. However, most of these methods of administration are still not ideal for targeting the central nervous system. Recently, therapeutic intranasal T administration (InT) has been considered as another option for delivering T to the brain. In the present study, the effects of 21-day InT treatment were assessed on open field behavior in gonadectomized (GDX) rats and intact rats. Subcutaneous injections of T at same dose were also tested in GDX rats. A total of 12 behavioral events were examined in GDX groups with or without T and in intact groups with or without InT. Significant decreases in open field activity were observed in rats after GDX without InT compared to sham-operated rats. The open field activity scores for most tests significantly increased with InT treatment in GDX rats and in intact rats compared with the corresponding GDX rats and intact rats. Intranasal administration of T improved the reduced behaviors resulted from T deficiency better than subcutaneous injection of T, demonstrating that T can be delivered to the brain by intranasal administration. Our results suggest that intranasal T delivery is an effective option for targeting the central nervous system.

Factors influencing time course of pain after depot oil intramuscular injection of testosterone undecanoate

Pain following depot intramuscular (IM) injection of oil vehicle-based drugs has been little studied. This study aimed to determine prospectively the prevalence, determinants, severity and functional consequences of pain during the week after IM injection of 1 000 mg testosterone undecanoate (TU) in a 4-mL castor oil vehicle. Androgen-deficient men receiving regular T replacement therapy at an academic andrology clinic were recruited to report pain scores using a coloured visual linear analogue scale at seven times over the first day and daily for a week after a deep IM gluteal injection. The time course and covariables influencing pain scores were analysed by mixed model analysis of variance (ANOVA). Following 168 injections in 125 men, pain was reported by 80% of men, peaking immediately after injection, reaching only moderate severity, lasting 1-2 days and returning to baseline by day 4. The pain required little analgesic use and produced minimal interference in daily activities. The time course of pain scores was reproducible in the 43 men who underwent two consecutive injections. Pain was more severe in men who had an earlier painful injection, but less severe in older and more obese men. There were negligible differences in post-injection pain experience between experienced nurses administering injections. Deep IM gluteal injection of depot TU in 4-mL castor oil is well tolerated and post-injection pain is influenced by earlier painful injection experience, as well as age and obesity.

Male contraception: A realistic option?

This review illustrates the principle of hormonal male contraception and gives an overview of current trials aiming at the development of a marketable hormonal contraceptive for men. The principle of male hormonal contraception is based on strong suppression of gonadotropins in order to arrest spermatogenesis at the spermatogonial stem cell level, thus leading to azoospermia or severe oligozoospermia. Until now, it has not been possible to interrupt spermatogenesis effectively without simultaneously inhibiting the production of androgens by Leydig cells, resulting in a deficiency of extra-testicular androgens. Therefore, testosterone needs to be replaced. By administering exogenous testosterone alone azoospermia can be reached in East Asians, whereas azoospermia is only achieved in two-thirds of Caucasian volunteers so that in these men an additional agent is required. Currently injectable testosterone combined with gestagens or administered as implants are being tested for possible licensing. Although scrotal and non-scrotal testosterone patches, orally administered testosterone undecanoate and testosterone gels are generally well tolerated and provide stable testosterone levels in the normal range, their use showed generally disappointing efficacy due to insufficient gonadotropin suppression. Further large multi-centre studies are required to establish the contraceptive efficacy of the most promising steroid combinations.

Testosterone for the aging male; current evidence and recommended practice

An international consensus document was recently published and provides guidance on the diagnosis, treatment and monitoring of late-onset hypogonadism (LOH) in men. The diagnosis of LOH requires biochemical and clinical components. Controversy in defining the clinical syndrome continues due to the high prevalence of hypogonadal symptoms in the aging male population and the non-specific nature of these symptoms. Further controversy surrounds setting a lower limit of normal testosterone, the limitations of the commonly available total testosterone result in assessing some patients and the unavailability of reliable measures of bioavailable or free testosterone for general clinical use. As with any clinical intervention testosterone treatment should be judged on a balance of risk versus benefit. The traditional benefits of testosterone on sexual function, mood, strength and quality of life remain the primary goals of treatment but possible beneficial effects on other parameters such as bone density, obesity, insulin resistance and angina are emerging and will be reviewed. Potential concerns regarding the effects of testosterone on prostate disease, aggression and polycythaemia will also be addressed. The options available for treatment have increased in recent years with the availability of a number of testosterone preparations which can reliably produce physiological serum concentrations.

Testosterone replacement therapy

Hypgonadism has important adverse effects on the health and quality of life of affected men, but remains underdiagnosed in clinical practice. This article reviews the physiology, causes and diagnosis of hypogonadism and the potential benefits of treatment with testosterone replacement therapy.

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.

Drug insight: testosterone preparations

Testosterone has been used for substitution therapy in testicular and hypothalamopituitary diseases for almost six decades, with injectable testosterone esters and implanted testosterone pellets being the mainstay of treatment. Growing interest in the possible use of testosterone in nonclassical situations such as male contraception, aging (late-onset hypogonadism), muscle-wasting conditions like HIV, erectile dysfunction, and female hypoactive sexual disorder has stimulated research, leading to the development of several new modes of administration of testosterone. Transdermal patches, gels, mucoadhesive sustained-release buccal tablets and long-acting testosterone esters are designed to provide testosterone levels that approximate normal physiologic levels, to improve patient acceptability, and to further increase the number of treatment options available. In this Review, we briefly describe the chemistry, mechanism of action, and metabolism of testosterone. We then discuss the pharmacokinetics, advantages, and disadvantages of various formulations and summarize the various preparations currently available.

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.

Testosterone Hormone Replacement Therapy: State-of-the-Art and Emerging Technologies

In the human male, testosterone is the major circulating androgen. The clinical effects of androgen are numerous, and testosterone deficiency is associated with a number of clinical abnormalities. At present, a variety of preparations containing testosterone is available for the treatment of androgen deficiency. Ideally, those treatments have to produce and maintain physiologic serum concentrations of the hormone. This article reviews the current existing testosterone dosage forms on the market with their advantages and drawbacks and examines new and emerging technology developments concerning this therapy. In particular, the latest innovations in transdermal delivery are explored.

New facets of androgen replacement therapy during childhood and adolescence

The goals of androgen therapy for adolescents are to promote linear growth and secondary sexual characteristics, at the same time as permitting the normal accrual of muscle mass and bone mineral content. Secondary goals are mainly in the psychosocial sphere, in which pubertally delayed boys feel that they look too young, are not considered a 'peer' in their age group and have difficulty competing in athletic endeavours. These goals are irrespective of the causes of delayed pubertal development: constitutional delay of growth and puberty (CDGP), a transient but very common form of pubertal delay and, much less commonly, primary or secondary permanent hypogonadism. Not all boys with CDGP require testosterone therapy, but those that come to a referral practice are likely candidates, as the watchful waiting period has finished. Although a range of androgen preparations is available for adults (injectable, oral, implantable and cutaneous patches and gels), most are drug delivery devices that are appropriate for full adult androgen replacement. These doses are too large for the induction of puberty. Therefore, at present, the injectable form is the only one that is easily adaptable for the increasing amounts of androgen necessary for the various stages of pubertal development. All preparations deliver testosterone that is readily converted to dihydrotestosterone by 5-alpha reductase. The author's practice is to begin with injecting 50-75 mg of one of the long-acting esters (enanthate or cypionate) per month, and gradually escalate to 100-150 mg/month, before changing to twice monthly dosage. As most adolescents have delayed puberty, the therapy is needed for 6-18 months before the hypothalamic-pituitary-gonadal axis functions at the late adolescent/adult level in those with CDGP. Those with permanent hypogonadism will require lifelong therapy. Once adequate virilisation is induced, and virtually full adult height is reached, any of the therapies noted above can be used in those permanently hypogonadal, whether primarily or secondarily.

Levonorgestrel implants enhanced the suppression of spermatogenesis by testosterone implants: comparison between Chinese and non-Chinese men

CONTEXT

Previous male contraceptive studies showed that progestins enhance spermatogenesis suppression by androgens in men.

OBJECTIVE

We compared the efficacy of spermatogenesis suppression by the combination of levonorgestrel (LNG) with testosterone (T) implants to that by T implants alone in two different ethnic groups.

DESIGN

This was a randomized trial performed in two centers with two treatment groups.

SETTINGS

The study was performed at the Academic Medical Center in the United States and the Research Institute in China.

PARTICIPANTS

Forty non-Chinese and 40 Chinese healthy male volunteers were studied.

INTERVENTIONS

Subjects were randomized to receive four LNG implants together with four T implants (inserted on d 1 and wk 15-18) vs. T implants alone for 30 wk.

MAIN OUTCOME MEASURES

The primary end point compared the efficiency of suppression to severe oligozoospermia (1 x 10(6)/ml) by LNG plus T implants vs. that by T implants alone. The secondary end point examined differences in spermatogenesis suppression between Chinese and non-Chinese subjects.

RESULTS

LNG plus T implants caused more suppression of spermatogenesis to severe oligozoospermia during the treatment period than T implants alone at both sites (P < 0.02). In Chinese men, severe oligozoospermia was achieved in more than 90% of the men in both treatment groups. Suppression to severe oligozoospermia was less in the non-Chinese men (59%) after T alone (P < 0.020); this difference disappeared with combined treatment (89%). T implant extrusion occurred in six men. Acne and increased hemoglobin were the most common adverse events.

CONCLUSION

T implants resulted in more pronounced spermatogenesis suppression in Chinese men. Addition of LNG implants to T implants enhanced the suppression of spermatogenesis in the treatment period in both Chinese and non-Chinese men.

Male hypogonadism : an update on diagnosis and treatment

Male hypogonadism is one of the most common endocrinologic syndromes. The diagnosis is based on clinical signs and symptoms plus laboratory confirmation via the measurement of low morning testosterone levels on two different occasions. Serum luteinizing hormone and follicle-stimulating hormone levels distinguish between primary (hypergonadotropic) and secondary (hypogonadotropic) hypogonadism. Hypogonadism associated with aging (andropause) may present a mixed picture, with low testosterone levels and low to low-normal gonadotropin levels. Androgen replacement therapy in hypogonadal men has many potential benefits: improved sexual function, an enhanced sense of well-being, increased lean body mass, decreased body fat, and increased bone density. However, it also carries potential risks, including the possibility of stimulating the growth of an occult prostate cancer. The benefits of androgen therapy outweigh the risks in men with classic hypogonadism. However, for men with mild hypogonadism or andropause, the balance between benefits and risks is not always clear. Unfortunately, studies to date have included too small a number of patients and have been too short in duration to provide meaningful data on the long-term risks versus the benefits of androgen replacement therapy in these populations. Several products are currently marketed for the treatment of male hypogonadism. Weekly-to-biweekly injections of testosterone cypionate (cipionate) or testosterone enanthate (enantate) are widely used, as they are economical and generally well tolerated. However, once-daily transdermal therapies have become increasingly popular and now include both patch and gel systems. Intramuscular injection of testosterone undecanoate is an attractive new therapy that can be administered quarterly. To confirm an adequate replacement dosage, assessment of clinical responses and measurement of serum testosterone levels generally suffice. For selected men, serial measurement of bone mineral density during androgen therapy might be helpful to confirm end-organ effects. For men aged >50 years, we advocate measurement of hematocrit for detection of polycythemia and a digital rectal examination with a serum prostate-specific antigen level measurement for prostate cancer screening during the first few months of androgen therapy. Subsequently, a hematocrit should be obtained yearly or after changes in therapy, and annual prostate cancer screening can be offered to the patient after a discussion of its risks and benefits.

Androgen Deficiency in the Etiology and Treatment of Erectile Dysfunction

The evaluation and management of erectile dysfunction (ED) has evolved dramatically following the introduction of oral phosphodiesterase-5 inhibitors. Despite the limited role of directed diagnostic testing in the evaluation of the impotent patient, routine de-termination of a serum testosterone likely is indicated based on evidence that testosterone modulates erectile function, that hypogonadism is prevalent among elderly men and men with ED, and that symptomatology alone rarely detects hypogonadism. Forms of testosterone commonly used include oral, parenteral, transdermal, and implantable preparations, each with significant advantages and disadvantages. The risks and benefits of testosterone supplementation have been characterized incompletely and will require further validation before widespread use of testosterone as hormone replacement therapy in aging men.

A review of hypogonadism and erectile dysfunction among HIV-infected men during the pre- and post-HAART eras: diagnosis, pathogenesis, and management

Hypogonadism and erectile dysfunction (ED) appear to be more common among men infected with HIV compared to age-matched men within the general U.S. population. HIV providers should consider these conditions and utilize standardized evaluation and diagnostic criteria. Treatment of both hypogonadism and ED increases sexual function and quality of life; testosterone supplementation in the setting of hypogonadism may also improve lean body mass, mental status, and anemia. We review the epidemiology, diagnosis, pathogenesis, and treatment options of both hypogonadism and ED among HIV-infected men.

Testosterone replacement therapy for male hypogonadism: Part III. Pharmacologic and clinical profiles, monitoring, safety issues, and potential future agents

Male hypogonadism is associated with potentially distressing adverse effects on diverse organs and tissues. These include sexual dysfunction, particularly diminished libido, as well as mood disturbances, reduced lean body mass, and increased adipose-tissue mass. A wide range of effective and well-tolerated options exists. These include relatively noninvasive therapies, such as testosterone (T) gels and T patches; slightly more invasive treatments, such as the T buccal system; and invasive therapies, such as intramuscular T injections and subcutaneous depot implants (T pellets). Testosterone replacement therapy (TRT) can be individualized to enhance patient health and well-being. Screening and ongoing monitoring are necessary to ensure both the efficacy and safety of TRT, particularly prostate safety. Investigational agents, including selective androgen receptor modulators, may offer new pharmacodynamic and/or pharmacokinetic properties that enhance outcomes of TRT.

Update on the male hormonal contraceptive agents

There remains a need for new acceptable and effective male contraceptives to increase the choice for couples throughout the world. There have been no recent advances in available male contraceptive methods although a number of promising approaches have been identified, of which the hormonal approach is currently undergoing clinical investigation. In recent years the pace of research in this area has quickened significantly with increasing interest and now investment by the pharmaceutical industry. This is vital if the work undertaken so far by the public sector is to be transformed into a commercial reality. The hormonal approach is based on suppression of pituitary gonadotropin secretion resulting in a reversible reduction in spermatogenesis with azoospermia in all men being the ultimate aim. Without stimulation by luteinising hormone from the pituitary, testicular testosterone production also ceases. Therefore, androgen administration to restore physiological levels is an essential component of all male hormonal contraceptive regimes. Male hormonal contraceptives can consist of testosterone alone, or either a progestogen or gonadotropin-releasing hormone antagonist with 'add-back' testosterone. This article reviews the current state of progress in this field.

Adequacy of androgen replacement influences bone density response to testosterone in androgen-deficient men

OBJECTIVE

Androgen deficiency (AD) leads to bone loss and contributes to osteoporotic fractures in men. Although low bone mineral density (BMD) in AD men is improved by testosterone replacement, the responses vary between individuals but the determinants of this variability are not well defined.

DESIGN AND METHODS

Retrospective review of dual energy X-ray absorptiometry (DEXA) of the lumbar spine and proximal femur in men with established AD requiring regular androgen replacement therapy (ART). After a DEXA scan all men were treated with testosterone implants (800 mg, approximately 6 month intervals). Patients were classified as having a congenital, childhood, or post-pubertal onset, as well as according to the adequacy of treatment prior to their first DEXA scan as untreated, partially treated or well treated.

RESULTS

Men with AD requiring regular ART (n = 169, aged 46.3+/-1.1 years, range 22-84 years) underwent a DEXA scan prior to being treated with testosterone implants (800 mg, approximately 6 month intervals). In cross-sectional analysis at the time of the first DEXA scan untreated men (n = 24) had significantly reduced age-adjusted BMD at all four sites (L1-L4, femoral neck, Ward's triangle and trochanter). Well-treated men (n = 77) had significantly better age-adjusted BMD at all four sites compared with those who were partially treated (n = 66) or untreated (n = 24) with their age-adjusted BMD being normalized. In a longitudinal assessment of men (n = 60) who had two or more serial DEXA scans, at the second DEXA scan after a median of 3 years, men who were previously partially treated (n = 19) or untreated (n = 11) had proportionately greater improvements in BMD, significantly for Ward's triangle (P = 0.025) and the trochanter (P = 0.044) compared with men (n = 30) previously well treated.

CONCLUSIONS

The present study demonstrates a positive relationship between adequacy of testosterone replacement and BMD in men with overt organic AD. Additionally, the BMD of well-treated AD men approximates that of age-matched non-AD controls. The greatest BMD gains are made by those who have been either untreated or partially treated, and optimal treatment over time (median 3 years) normalizes BMD to the level expected for healthy men of the same age.

Ascertainment and Treatment of Delayed Puberty

The majority of patients with pubertal delay, can be classified as having primary pubertal delay (constitutional delay of growth and puberty, CDGP), although any child with a chronic disease could present with delayed puberty. In contrast, children with hypogonadism, either hyper- or hypogonadotropic, exhibit a total absence of pubertal development. Hence, early evaluation of these patients should be performed. Delay of puberty leads to psychological problems, secondary to short stature and/or delay in the acquisition of secondary sex characteristics and the reduction of bone mass. Although the final height in patients with CDGP is usually normal, some of these patients do not reach the third percentile or remain in the lowest part of the growth chart according to familial height. The most common reason for treating CDGP patients, usually with sex steroids, is for psychological difficulties and for loss of bone mineralization. Treatment must be individualized. Therapeutic options and new drugs will be discussed. Appropriate treatment and adequate nutritional intake are indicated in patients with delayed puberty due to chronic illness. In patients with hypo- or hypergonadotropic hypogonadism, puberty must be induced or completed. Different treatments (GnRH analogues, gonadotropins and sex steroids), and the main objectives are discussed.

Striant SR: a novel, effective and convenient testosterone therapy for male hypogonadism

Striant SR (marketed as Striant in the US) is a novel sustained-release mucoadhesive buccal testosterone tablet for the treatment of male hypogonadism. Striant SR restores serum testosterone concentrations to the physiological range within 4 h of application, and steady-state concentrations are achieved within 24 h of twice-daily dosing. In phase III clinical trials, 87-97% of patients using Striant SR achieved 24-h-averaged serum testosterone concentrations within the normal range. In a comparative study, Striant SR was more likely to restore testosterone concentrations to the physiological range than Andropatch. In a small study, Striant SR produced steady-state testosterone concentrations comparable with those achieved with a testosterone gel (50mg testosterone). Striant SR was well tolerated, with a low incidence of adverse events and a low discontinuation rate (3.5%) due to adverse events in phase III studies. Striant SR is an effective, well-tolerated, convenient and discreet treatment for male hypogonadism.

Hormone replacement therapy in hypopituitarism

Hypopituitarism is a disease complex characterised by varying pituitary hormonal deficiencies. The causes and manifestations of hypopituitarism are diverse, the most common being the presence of or treatment of a pituitary adenoma. Pressure effects from the tumour itself on normal pituitary tissue, together with the effects of surgical resection, results in variable degrees of hypopituitarism. The latter precipitates end-organ failure leading to a variety of symptoms and signs, which are often nonspecific and vague. The broad aims of managing patients with hypopituitarism are to provide amelioration of the symptomatology associated with the condition, to avoid potentially acute life-threatening complications and to protect against long-term sequelae that may include osteoporosis and cardiovascular disease. This is achieved through lifelong therapeutic replacement of target hormonal deficiencies, such as corticosteroids or sex hormones, or replacement of the pituitary hormones themselves (i.e., growth hormone and vasopressin). Although the general principle of replacing missing hormones seems straightforward, in reality, existing hormonal therapeutic regimes often result in unphysiological replacement. Furthermore, there may be problems associated with their administration and routine monitoring. There is now little doubt that the hypopituitary state is associated with increased cardiovascular mortality. However, the precise underlying mechanisms responsible have not been fully elucidated, but probably include untreated growth hormone deficiency and/or unphysiological replacement of other target hormones. An effective strategy of tailoring hormonal replacement regimes to individual needs remains a challenge but is imperative if the increased morbidity and mortality associated with hypopituitarism is to be addressed.

Testosterone replacement therapy: current trends and future directions

Male hypogonadism is characterized by abnormally low serum testosterone levels associated with typical symptoms, including mood disturbance, sexual dysfunction, decreased muscle mass and strength, and decreased bone mineral density. By restoring serum testosterone levels to the normal range using testosterone replacement therapy, many of these symptoms can be relieved. For many years, injectable testosterone esters or surgically implanted testosterone pellets have been the preferred treatment for male hypogonadism. Recently, newer treatment modalities have been introduced, including transdermal patches and gels. The development of a mucoadhesive sustained-release buccal tablet is the latest innovation, which will provide patients with an additional option. The availability of new treatment modalities has helped to renew interest in the management of male hypogonadism, highlighting the need to address a number of important but previously neglected questions in testosterone replacement therapy. These include the risks and benefits of treatment in different patient populations (e.g. the elderly) and the need for evidence-based diagnosis and treatment monitoring guidelines. While some recommendations have been developed in individual countries, up-to-date, internationally accepted evidence-based guidelines that take into account national differences in clinical practice and healthcare delivery would optimize patient care universally.

Testosterone release rate and duration of action of testosterone pellet implants

OBJECTIVE

Testosterone pellets are a highly effective subdermal depot administered at regular intervals with the timing individualized depending upon return of the patient's characteristic androgen deficiency symptoms. Yet the in vivo testosterone release rate and effective duration of action of these pellets has been little studied systematically.

DESIGN

Analysis of prospectively collected data from three randomized controlled clinical trials. Collection of extruded pellets.

PATIENTS

Androgen-deficient men (n = 136) undergoing long-term androgen replacement therapy with a standard dose (800 mg) of testosterone pellets implanted subdermally at intervals from 5 to 7 months.

MEASUREMENTS

Testosterone release rate of pellets, consisting of pure crystalline testosterone without excipients, is estimated by measuring the dry weight lost by pellets (n = 179) over their time in situ. The effective duration of the standard regimen, and the influence of extrusion and patient or procedural characteristics on it, was estimated by timing of return for re-implantation due to recurrence of the patient's familiar androgen deficiency symptoms.

RESULTS

The loss of dry weight of intact (n = 112) pellets was strongly correlated with time in situ (r2 = 0.969) providing an estimate of daily testosterone release rate per 200 mg pellet of 1.34 +/- 0.02 mg/pellet/day (95% CI 1.30-1.37 mg/day) for the first 3 months. After 756 implantations of the standard dose, men return for re-implantation at 5.8 calendar months following no or only a single pellet extrusion, but the time to return was significantly shorter after multiple extrusions. No patient or procedural features influenced the timing of return. Among men with primary hypogonadism, increases in plasma LH and FSH were more sensitive than plasma total or free testosterone to changes in testosterone delivery following an extrusion.

CONCLUSION

Testosterone pellet implants release testosterone at a steady rate of 1.3 mg/200 mg implant/day (95% CI). The duration of action is about 6 months in an uncomplicated cycle with timing of return shortened by extrusions only in the 3.6% of procedures followed by multiple extrusions. No other patient or procedural features influenced duration of action. Among men with an intact hypothalamo-pituitary unit, plasma gonadotropins are more sensitive than blood total or free testosterone to reduced testosterone delivery following an extrusion.

Androgen Replacement Therapy

The major goal of androgen substitution is to replace testosterone at levels as close to physiological levels as is possible. For some androgen-dependent functions testosterone is a pro-hormone, peripherally converted to 5alpha-dihydrotestosterone (DHT) and 17beta-estradiol (E2), of which the levels preferably should be within normal physiological ranges. Furthermore, androgens should have a good safety profile without adverse effects on the prostate, serum lipids, liver or respiratory function, and they must be convenient to use and patient-friendly, with a relative independence from medical services. Natural testosterone is viewed as the best androgen for substitution in hypogonadal men. The reason behind the selection is that testosterone can be converted to DHT and E2, thus developing the full spectrum of testosterone activities in long-term substitution. The mainstays of testosterone substitution are parenteral testosterone esters (testosterone enantate and testosterone cipionate) administered every 2-3 weeks. A major disadvantage is the strongly fluctuating levels of plasma testosterone, which are not in the physiological range at least 50% of the time. Also, the generated plasma E2 is usually supraphysiological. A major improvement is parenteral testosterone undecanoate producing normal plasma levels of testosterone for 12 weeks, with normal plasma levels of DHT and E2 also. Subcutaneous testosterone implants provide the patient, depending on the dose of implants, with normal plasma testosterone for 3-6 months. However, their use is not widespread. Oral testosterone undecanoate dissolved in castor oil bypasses the liver via its lymphatic absorption. At a dosage of 80 mg twice daily, plasma testosterone levels are largely in the normal range, but plasma DHT tends to be elevated. For two decades transdermal testosterone preparations have been available and have an attractive pharmacokinetic profile. Scrotal testosterone patches generate supraphysiological plasma DHT levels, which is not the case with the nonscrotal testosterone patches. Transdermal testosterone gel produces fewer skin irritations than the patches and offers greater flexibility in dosage. Oromucosal testosterone preparations have recently become available. Testosterone replacement is usually of long duration and so patient compliance is of utmost importance. Therefore, the patient must be involved in the selection of type of testosterone preparation. Administration of testosterone to young individuals has almost no adverse effects. With increasing age the risk of adverse effects on the prostate, the cardiovascular system and erythropoiesis increases. Consequently, short-acting testosterone preparations are better suited for aging androgen-deficient men.

Androgens and the ageing male and female

Androgens play a number of important physiological roles in the human. In the male, testosterone is required for virilization, normal sexual function, and both stimulation and maintenance of bone and muscle mass. Epidemiological studies have shown a progressive decline in testosterone levels with ageing in men. The clinical significance of this decline is still unclear, and there is controversy as to whether a specific syndrome of androgen deficiency or 'andropause' exists. The benefits of testosterone supplementation in this age group have yet to be equivocally established, and long-term safety data on testosterone administration in this setting are lacking. In the female, a decline in testosterone levels with ageing has been less clearly established due, at least in part, to the absence of sensitive assays. Available data suggest that the major role of testosterone replacement after menopause may be in those women who have had an oophorectomy.

Bone mineral density outcomes following long-term treatment with subcutaneous testosterone pellet implants in male hypogonadism

BACKGROUND

Osteoporosis is a common complication of untreated male hypogonadism. Even mild hypogonadism due to suboptimal testosterone replacement may result in decreased bone mineralization and osteoporosis.

OBJECTIVE

To assess bone mineral density in hypogonadal men following long-term long-acting subcutaneous testosterone pellet implants as replacement therapy.

PATIENTS

A cross-sectional study of 37 patients with primary or secondary hypogonadism receiving long-term (mean 6.6 years) subcutaneous testosterone pellet implants as replacement therapy.

MEASUREMENTS

Bone mineral density was measured in all patients using dual energy X-ray absorptiometry. Serum testosterone 3-4 months after insertion of pellets was measured in all patients to assess adequacy of replacement therapy.

RESULTS

Mean areal bone mineral density were 1.02 (SD 0.14) g/cm2 with a mean Z score of -0.64 (SD 1.3) and 0.87 (SD 0.13) g/cm2 with a mean Z score of -0.72 (SD 1.2) at lumbar spine and neck of femur, respectively. Mean serum testosterone 3-4 months after pellets insertion was 15.45 nmol/l (SD 4.2 nmol/l). There was no significant correlation between bone mineral density and patient's age at start or duration of testosterone therapy.

CONCLUSIONS

Bone mineral density in long-term regularly treated hypogonadal men was not different from the age-matched reference range for normal men. Long-acting subcutaneous testosterone pellet implants as replacement therapy in male hypogonadism are safe, acceptable to the patient, result in adequate bone mass accumulation and maintenance of normal bone mineral density. By provision of sustained physiological levels of testosterone they may contribute to increased androgen effect at the receptor level.

Male contraception

The provision of safe, effective contraception has been revolutionized in the past 40 yr following the development of synthetic steroids and the demonstration that administration of combinations of sex steroids can be used to suppress ovulation and, subsequently, other reproductive functions. This review addresses the current standing of male contraception, long the poor relation in family planning but currently enjoying a resurgence in both scientific and political interest as it is recognized that men have a larger role to play in the regulation of fertility, whether seen in geopolitical or individual terms. Condoms and vasectomy continue to be popular at particular phases of the reproductive lifespan and in certain cultures. Although not perfect contraceptives, condoms have the additional advantage of offering protection from sexually transmitted infection. The hormonal approach may have acquired the critical mass needed to make the transition from academic research to pharmaceutical development. Greatly increased understanding of male reproductive function, partly stimulated by interest in ageing and the potential benefits of androgen replacement, is opening up other avenues for investigation taking advantage of nonhormonal regulatory pathways specific to spermatogenesis and the reproductive tract.

Treatment options for a patient experiencing pruritic rash associated with transdermal testosterone: a review of the literature

A 22-year-old man with hypogonadotropic hypogonadism was receiving monthly intramuscular injections of testosterone replacement therapy. The patient refused to self-administer the injections because of discomfort, so the therapy was switched to testosterone patches. He experienced a pruritic, macular, erythematous rash underneath the reservoir area of two different transdermal formulations, which did not improve after pretreatment with topical corticosteroids. Eventually, he tolerated application of a testosterone gel and his serum testosterone levels returned to normal after 1 month of therapy. Commercially available and investigational testosterone products and therapeutic monitoring guidelines for androgen replacement are reviewed.

Influence of implantation site and track geometry on the extrusion rate and pharmacology of testosterone implants

BACKGROUND

Implantation of testosterone pellets under the lateral abdominal wall skin is an old but popular and effective form of androgen replacement therapy. Extrusion of one or more pellets remains the most frequent adverse event.

OBJECTIVE

To determine whether an alternative implantation site (hip) and/or track geometry (two vs. four tracks) would reduce extrusion rates compared with the standard of a four-track abdominal site. Additionally, the study aimed to evaluate the effects of site and track geometry on other adverse effects (bruising, infection) and the pharmacology of testosterone release from the implants.

DESIGN

A prospective, parallel-group unmasked study design in a single centre. The primary objective was to evaluate sites, with evaluation of track geometry a subordinate objective made necessary by anatomical differences. Accordingly, androgen deficient men requiring testosterone implantation with the standard dose (four 200 mg pellets) were randomized into one of three groups (ratio 1 : 1 : 2): a four-track abdomen site (standard), a two-track abdomen site or a two-track hip site. The pharmacological substudy was to evaluate the impact of site and track geometry on testosterone implant pharmacology by monthly hormone assays following implantation.

PATIENTS

Two hundred and forty-six implantation procedures involving 96 androgen deficient men.

MEASUREMENTS

The primary end-point, extrusion rate per procedure, and secondary end-points (bruising or infection post procedure) were evaluated prospectively by self-report from the participants, and verified when they returned next for implantation. The pharmacology substudy involved monthly blood sampling for hormone (total and free testosterone, LH, FSH) measurements.

RESULTS

The extrusion rate was significantly higher [odds ratio (OR) = 2.6, 95% confidence interval (CI) 1.1-7.1] for the hip site (15/125, 12%) compared with the abdominal site (6/121, 5%). Track geometry made no significant difference (OR = 1.05, 95% CI 0.2-5.4) to the extrusion rate. No secondary end-points (bruising, infection) were significantly different according to either site or track geometry. One operator who performed the implant procedures had significantly less primary and secondary adverse events than the other operators (P = 0.006). Neither implantation site, nor track geometry influenced pharmacokinetics [peak plasma total and free testosterone concentrations and net hormone release (area-under-curve, AUC)] or pharmacodynamics [nadir plasma LH and FSH and net suppression (AUC) in men with hypergonadotrophic hypogonadism].

CONCLUSIONS

We conclude that the hip site has a higher extrusion rate than the standard abdominal wall site but that track geometry does not increase the risk of extrusion. Neither implantation site, nor track geometry influenced either other adverse effects or the pharmacokinetics or pharmacodynamics of testosterone pellet implants.