Prasterone

PURPOSE

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects and toxicities, drug interactions, dosage and administration, and safety issues related to the use of prasterone are discussed.

SUMMARY

Prasterone is a proprietary synthetic dehydroepiandrosterone product under investigation for use in women with systemic lupus erythematosus (SLE) who are taking glucocorticoids. Initial trials investigated prasterone as a treatment to improve disease activity and symptoms in women with mild to moderate SLE. The Food and Drug Administration (FDA) did not approve prasterone's labeling for these indications. Subsequent trials have focused on prasterone as a treatment to limit bone loss in women who have SLE. A study was conducted to assess bone mineral density in patients who had been taking glucocorticoids for six months or longer. The patients in the prasterone group showed an increase in bone mineral density, while the placebo group demonstrated a loss. The most common adverse effects of prasterone therapy were acne and hirsutism. Hematuria, hypertension, and serum creatinine concentration increases have also occurred. Interactions of prasterone potentially exist with 5-alpha reductase inhibitors and additive or antagonistic effects could possibly occur with androgens, estrogens, oral contraceptives, and progestins. In clinical trials, oral prasterone dosages of 100-200 mg/day were administered. These dosages have resulted in supraphysiological hormone levels.

CONCLUSION

FDA has granted orphan drug status for the prevention of loss of bone mineral density in SLE patients taking glucocorticoids. FDA is requesting additional Phase III trial data for the treatment of SLE and the prevention of loss of bone mineral density.

A decrease in the plasma DHEA to cortisol ratio during smoking abstinence may predict relapse: a preliminary study

RATIONALE

Increases in depressive symptoms during smoking cessation have been associated with risk for relapse. Several studies have linked plasma levels of cortisol and dehydroepiandrosterone (DHEA) or DHEA-sulfate (DHEAS) to depressive symptoms.

OBJECTIVES

To determine whether changes in plasma cortisol, DHEA, or DHEAS levels and emergence of depressive symptoms during smoking cessation are associated with smoking relapse.

MATERIALS AND METHODS

Subjects were healthy non-medicated men and women, aged 39+/-12 years, who smoked, on average, 22 cigarettes per day. Depressive symptoms, smoking withdrawal symptoms, and plasma steroid levels were measured before and after 8 days of verified smoking abstinence. Relapse status at day 15 was then determined.

RESULTS

In the full sample (n=63), there was a trend for changes in depressive symptoms to be associated with relapse. In the subset of 25 subjects with plasma neuroactive steroid data, there was a significant interaction between the change in the plasma DHEA/cortisol ratio from day 0 to day 8 and relapse status at day 15. This ratio was similar before abstinence, but lower at day 8 in relapsed, compared to abstinent, subjects. Changes in the DHEA/cortisol ratio tended to predict changes in depressive symptoms in the women only.

CONCLUSION

A decrease in the plasma DHEA/cortisol ratio during 8 days of smoking abstinence was associated with relapse over the following week. Further research is needed to fully characterize sex-specific relationships between abstinence-induced changes in neuroactive steroid levels, depressive or withdrawal symptoms, and relapse. Such research may lead to new interventions for refractory smoking dependence.

Delayed effects of short-term transdermal application of 7-oxo-dehydroepiandrosterone on its metabolites, some hormonal steroids and relevant proteohormones in healthy male volunteers

Twenty-one healthy male volunteers aged 20–70years were given transdermally 25mg of 7-oxo-dehydroepiandrosterone daily in the form of an emulgel for 8 consecutive days. Morning blood was collected as follows: before application, and after the first, fourth and eighth doses (days 0, 2, 5 and 9), and then at different time intervals after termination of the treatment (days 16, 23, 37, 51, 72 and 100). Cortisol, testosterone, epitestosterone, estradiol, dehydroepiandrosterone and its sulfate, 7α- and 7β-hydroxy-dehydroepiandrosterone, luteinizing hormone, follicle-stimulating hormone and sex hormone-binding globulin were measured in blood sera. In the course of treatment 7β-hydroxy-dehydroepiandrosterone was significantly increased; testosterone and gonadotropins were lowered, but only after the first dose. All other significant changes were observed duringthe period after termination of the application:7β-hydroxy-dehydroepiandrosterone remained increased for 28days, 7α-hydroxy-dehydroepiandrosterone, testosterone, estradiol and sex hormone-binding globulin were decreased as late as day 63 and 91, respectively. On the other hand, epitestosterone was significantly increased between days 23 and 100. The levels of all other parameters studied were not significantly changed. The study points to an immediate as well as delayed effect of the short-term transdermal application of 7-oxo-dehydroepiandrosterone on relevant hormonal parameters.

Correlation of in vitro chemopreventive efficacy data from the human epidermal cell assay with animal efficacy data and clinical trial plasma levels

The human epidermal cell (HEC) assay, which uses carcinogen exposed normal skin keratinocytes to screen for cancer prevention efficacy, was used to screen possible preventive agents. The endpoints measured were inhibition of carcinogen-induced growth and induction of involucrin, an early marker of differentiation. Sixteen of twenty agents (apigenin, apomine, budesonide, N-(2-carboxyphenyl)retinamide, ellagic acid, ibuprofen, indomethacin, melatonin, (-)-2-oxo-4-thiazolidine carboxylic acid, polyphenon E, resveratrol, beta-sitosterol, sulfasalazine, vitamin E acetate, and zileuton) were positive in at least one of the two assay endpoints. Four agents (4-methoxyphenol, naringenin, palmitoylcarnitine chloride, and silymarin) were negative in the assay. Nine of the sixteen agents were positive for both endpoints. Agents that showed the greatest response included: ellagic acid > budesonide, ibuprofen > apigenin, and quinicrine dihydrochloride. Fifty-eight of sixty-five agents that have been evaluated in the HEC assay have also been evaluated in one or more rodent bioassays for cancer prevention and several are in clinical trials for cancer prevention. The assay has an overall predictive accuracy of approximately 91.4% for efficacy in rodent cancer prevention irrespective of the species used, the tissue model, or the carcinogen used. Comparison of the efficacious concentrations in vitro to plasma levels in clinical trials show that concentrations that produced efficacy in the HEC assay were achieved in clinical studies for 31 of 33 agents for which plasma levels and/or C(max) levels were available. For two agents, 9-cis-retinoic acid (RA) and dehydroepiandrosterone (DHEA), the plasma levels greatly exceeded the highest concentration (HC) found to have efficacy in vitro. Thus, the HEC assay has an excellent predictive potential for animal efficacy and is responsive at clinically achievable concentrations.

The Use of Dehydroepiandrosterone Therapy in Clinical Practice

Dehydroepiandrosterone (DHEA) therapy is controversial due to sensationalized reports of epidemiologic studies and the over-the-counter availability of DHEA. Human clinical trials have investigated the potential efficacy of DHEA therapy in multiple conditions with resultant inconsistencies in findings. DHEA is unique compared with other adrenal steroids because of the fluctuation in serum levels found from birth into advancing age. The lower endogenous levels of DHEA and DHEA sulfate found in advancing age have been correlated with a myriad of health conditions. Also, some studies suggest gender-specific actions of endogenous and exogenous DHEA. We reviewed only pharmacokinetic studies and human clinical trials investigating the efficacy of DHEA therapy that were placebo-controlled as these provided the most reliable scientific basis for the evaluation of DHEA therapy. Pharmacodynamic studies suggest that doses of 30-50mg of oral DHEA may produce physiologic androgen levels, especially in women. These studies report a dose-dependent effect and lack of accumulation of serum androgen levels. Pharmacologic studies also reveal a gender-specific response to DHEA therapy such that testosterone levels are increased in women but not in men. Clinical trials suggest that 50mg of oral DHEA, but not <30mg, can increase serum androgen levels to within the physiologic range for young adults with primary and secondary adrenal insufficiency, possibly improve sexual function, improve mood and self-esteem, and decrease fatigue/exhaustion. Whereas DHEA replacement therapy may be effective in treating patients with adrenal insufficiency, human clinical trials investigating its efficacy in conditions such as systemic lupus erythematosus, HIV, Alzheimer disease, advancing age, male sexual dysfunction, perimenopausal symptoms, depression, and cardiovascular disease have not provided consistent findings.

Dehydroepiandrosterone (DHEA) and the aging brain: flipping a coin in the "fountain of youth"

The physiological role of dehydroepiandrosterone (DHEA) and its sulphated ester DHEA(S) has been studied for nearly 2 decades and still eludes final clarification. The major interest in DHEA derives from its unique pattern of activity. Its levels exhibit a dramatic age-related decline that supports significant involvement of DHEA(S) in the aging process. Particularly relevant to the aging process is the functional decline that involves memory and cognitive abilities. DHEA is derived mainly from synthesis in the adrenal glands and gonads. It can also be detected in the brain where it is derived from a synthesis that is independent from peripheral steroid sources. For this reason DHEA and other steroid molecules have been named "neurosteroids." Pharmacological studies on animals provided evidence that neurosteroids could be involved in learning and memory processes because they can display memory-enhancing properties in aged rodents. However, human studies have reported contradictory results that so far do not directly support the use of DHEA in aging-related conditions. As such, it is important to remember that plasma levels of DHEA(S) may not reflect levels in the central nervous system (CNS), due to intrinsic ability of the brain to produce neurosteroids. Thus, the importance of neurosteroids in the memory process and in age-related cognitive impairment should not be dismissed. Furthermore, the fact that the compound is sold in most countries as a health food supplement is hampering the rigorous scientific evaluation of its potential. We will describe the effect of neurosteroids, in particular DHEA, on neurochemical mechanism involved in memory and learning. We will focus on a novel effect on a signal transduction mechanism involving a classical "cognitive kinase" such as protein kinase C. The final objective is to provide additional tools to understand the physiological role and therapeutic potentials of neurosteroids in normal and/or pathological aging, such as Alzheimer's disease.

Differential effects on the androgen status of postmenopausal women treated with tibolone and continuous combined estradiol and norethindrone acetate replacement therapy

OBJECTIVE

To determine serum parameters reflective of androgen status in postmenopausal women using two types of hormone replacement therapy (HRT).

DESIGN

Randomized, double-blind, prospective 1-year trial of two oral HRT regimens.

SETTING

University hospital, department of obstetrics and gynecology, menopause clinic.

PATIENT(S)

100 postmenopausal women > or = 45 years.

INTERVENTION(S)

Daily use of the progestogen tibolone (2.5 mg; n = 50) or continuous combined 17-beta-estradiol (2 mg) and norethindrone acetate (E+NA, 1 mg; n = 50).

MAIN OUTCOME MEASURE(S)

Measurements of total testosterone (total T), dehydroepiandrosterone sulfate (DHEAS), androstenedione (A), FSH, and sex-hormone-binding globulin (SHBG), and calculations of free testosterone (free T). Assessment of changes from baseline within and between groups after 6 and 12 months.

RESULT(S)

We found significant differences (% changes) in the tibolone group compared to baseline within the groups after both 6 and 12 months, respectively. Levels of free T doubled, total T decreased slightly, and SHBG decreased by half; DHEAS increased by approximately 20%; and FSH decreased. In the E+NA group, levels of free T, total T, androstenedione, and FSH all decreased, and SHBG increased. Pre-trial levels of DHEAS, A, and total T were significantly higher in the E+NA group. Between groups throughout the study, the changes from baseline were significant due to the different extent of FSH reduction, and opposite changes of free T, SHBG, and DHEAS.

CONCLUSION(S)

Both regimens modify plasma androgens, DHEAS, and SHBG differently. Tibolone decreased the levels of SHBG, and substantially increased free T and to a lesser extent increased DHEAS; this may reflect a modification of adrenal androgen production. Continuous combined estradiol and norethindrone acetate HRT suppressed the peripheral plasma androgens mediated by increased levels of SHBG.