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Other names | PF-05314882; N-(3H-Imidazo(4,5-b)pyridin-2-ylmethyl)-2-fluoro-4-methyl-3-oxo-4-aza-5α-androst-1-ene-17β-carboxamide |
Routes of administration | By mouth |
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Chemical and physical data | |
Formula | C27H34FN5O2 |
Molar mass | 479.600 g·mol−1 |
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MK-0773, also known as PF-05314882, is a steroidal, orally active selective androgen receptor modulator (SARM) that was under development by Merck and GTx for the treatment of sarcopenia (loss of muscle mass) in women and men. [1] [2] [3] Clinical trials for sarcopenia began in late 2007 but the collaboration between Merck and GTx ended in early 2010 and GTx terminated development of MK-0773 shortly thereafter. [2] MK-0773 was developed as a more advanced version of the related compound TFM-4AS-1. [4]
MK-0773 is a 4-azasteroid [5] and a potent and selective agonist of the androgen receptor (AR). [1] It binds to the AR with an EC50 of 6.6 nM and is a partial agonist in transactivation modulation of the AR with an IP of 25 nM and Emax of 78% and has a TRAF2 Emax of 29% and an N/C interaction (virilization-related) counterscreen assay Emax of 2%. [1] That is, it produces promoter activation but induces the N/C interaction almost negligibly. [1] MK-0773 is reportedly four times as potent as testosterone as an agonist of the AR. [2] The drug is selective and does not bind to other steroid hormone receptors such as the progesterone receptor or glucocorticoid receptor and shows no significant inhibition of 5α-reductase (IC50 > 10 μM). [1] In addition, it is non-aromatizable and hence has no potential for estrogenic effects or side effects, like gynecomastia. [6] MK-0773 had similar effects on lipid metabolism relative to DHT, including a decrease in total cholesterol and high-density lipoprotein (HDL) of a similar magnitude. [1]
MK-0773 shows tissue-selective androgenic effects in vivo in animals. [1] It increases lean body mass with maximal anabolic effects that are approximately 80% of those of dihydrotestosterone (DHT). [1] However, it had less than 5% of the effect of DHT on uterine weight, about 30 to 50% of the increase of sebaceous gland area induced by DHT, and increased the weight of the seminal vesicles by 12% of that of DHT at the highest dosage assessed. [4] [1] It had similarly reduced effects on the prostate gland. [1] No significant increase in gene expression of six candidate genes related to virilization was observed. [7] As such, MK-0773 shows a profile of an anabolic SARM with limited effects on sebaceous glands and reproductive tissues in animals and a reduced propensity for virilization. [1]
In human clinical studies, MK-0773 produced anabolism in women and men while producing no or very low effects on sebaceous glands, the endometrium, or the prostate gland after 12 weeks of treatment. [1] [7] [8] [9] A decrease in total cholesterol and HDL was also observed in the clinical studies. [1] MK-0773 produced a significant increase in lean body mass in elderly (≥65 years of age) women with sarcopenia and moderate physical dysfunction. [10] [11] [12] It also increased muscle strength relative to placebo but this failed to reach statistical significance. [10] [12] MK-0773 has been associated with elevated liver enzymes in clinical studies. [10]
Dihydrotestosterone is an endogenous androgen sex steroid and hormone primarily involved in the growth and repair of the prostate and the penis, as well as the production of sebum and body hair composition.
Selective androgen receptor modulators (SARMs) are a class of drugs that selectively activate the androgen receptor in specific tissues, promoting muscle and bone growth while having less effect on male reproductive tissues like the prostate gland.
BMS-564,929 is an investigational selective androgen receptor modulator (SARM) which is being developed by Bristol-Myers Squibb for treatment of the symptoms of age-related decline in androgen levels in men ("andropause"). These symptoms may include depression, loss of muscle mass and strength, reduction in libido and osteoporosis. Treatment with exogenous testosterone is effective in counteracting these symptoms but is associated with a range of side effects, the most serious of which is enlargement of the prostate gland, which can lead to benign prostatic hypertrophy and even prostate cancer. This means there is a clinical need for selective androgen receptor modulators, which produce anabolic effects in some tissues such as muscle and bone, but without stimulating androgen receptors in the prostate.
S-40503 is an investigational selective androgen receptor modulator (SARM) developed by the Japanese company Kaken Pharmaceuticals, which was developed for the treatment of osteoporosis. SARMs are a new class of drugs which produce tissue-specific anabolic effects in some tissues such as muscle and bone, but without stimulating androgen receptors in other tissues such as in the prostate gland, thus avoiding side effects such as benign prostatic hypertrophy which can occur following treatment with unselective androgens like testosterone or anabolic steroids.
LGD-2226 is an investigational selective androgen receptor modulator (SARM), which is being developed for treatment of muscle wasting and osteoporosis.
Enobosarm, also formerly known as ostarine and by the developmental code names GTx-024, MK-2866, and S-22, is a selective androgen receptor modulator (SARM) which is under development for the treatment of androgen receptor-positive breast cancer in women and for improvement of body composition in people taking GLP-1 receptor agonists like semaglutide. It was also under development for a variety of other indications, including treatment of cachexia, Duchenne muscular dystrophy, muscle atrophy or sarcopenia, and stress urinary incontinence, but development for all other uses has been discontinued. Enobosarm was evaluated for the treatment of muscle wasting related to cancer in late-stage clinical trials, and the drug improved lean body mass in these trials, but it was not effective in improving muscle strength. As a result, enobosarm was not approved and development for this use was terminated. Enobosarm is taken by mouth.
Andarine is a selective androgen receptor modulator (SARM) which was developed by GTX, Inc for the treatment of conditions such as muscle wasting, osteoporosis, and benign prostatic hypertrophy (BPH), using the nonsteroidal antiandrogen bicalutamide as a lead compound. Development of andarine for all indications has been discontinued, in favor of the structurally related and improved compound enobosarm.
LGD-4033, also known by the developmental code name VK5211 and by the black-market name Ligandrol, is a selective androgen receptor modulator (SARM) which is under development for the treatment of muscle atrophy in people with hip fracture. It was also under development for the treatment of cachexia, hypogonadism, and osteoporosis, but development for these indications was discontinued. LGD-4033 has been reported to dose-dependently improve lean body mass and muscle strength in preliminary clinical trials, but is still being developed and has not been approved for medical use. The drug is taken by mouth.
Vosilasarm, also known by the development codes RAD140 and EP0062 and by the black-market name Testolone or Testalone, is a selective androgen receptor modulator (SARM) which is under development for the treatment of hormone-sensitive breast cancer. It is specifically under development for the treatment of androgen receptor-positive, estrogen receptor-negative, HER2-negative advanced breast cancer. Vosilasarm was also previously under development for the treatment of sarcopenia, osteoporosis, and weight loss due to cancer cachexia, but development for these indications was discontinued. The drug is taken by mouth.
LG121071 is a selective androgen receptor modulator (SARM) developed by Ligand Pharmaceuticals that was first described in 1999 and was the first orally active nonsteroidal androgen to be discovered. It is a tricyclic quinolone derivative, structurally distinct from other nonsteroidal AR agonists like andarine and enobosarm (ostarine). The drug acts as a high-affinity full agonist of the androgen receptor (AR), with a potency and efficacy that is said to be equivalent to that of dihydrotestosterone (DHT). Unlike testosterone, but similarly to DHT, LG121071 and other nonsteroidal androgens cannot be potentiated by 5α-reductase in androgenic tissues, and for this reason, show tissue-selective androgenic effects. In accordance, they are said to possess full anabolic activity with reduced androgenic activity, similarly to anabolic-androgenic steroids.
Cl-4AS-1 is a dual anabolic–androgenic steroid (AAS) and 5α-reductase inhibitor. It is a potent and selective full agonist of the androgen receptor (IC50 = 12 nM) and inhibitor of 5α-reductase types I and II (IC50 = 6 and 10 nM, respectively). Structurally, Cl-4AS-1 is a 4-azasteroid.
TFM-4AS-1 is a dual selective androgen receptor modulator (SARM) and 5α-reductase inhibitor. It is a potent and selective partial agonist (Emax = 55%) of the androgen receptor (IC50 = 30 nM) and inhibitor of 5α-reductase types I and II (IC50 = 2 and 3 nM, respectively). TFM-4AS-1 shows tissue-selective androgenic effects; it promotes the accumulation of bone and muscle mass and has reduced effects in reproductive tissues and sebaceous glands. In an animal study, TFM-4AS-1 stimulated sebaceous gland formation only 31% as much as dihydrotestosterone (DHT) at doses that were as anabolic or more so than DHT. In addition, TFM-4AS-1 only weakly promoted growth of the prostate gland and it partially antagonized the actions of DHT in the seminal vesicles and endogenous androgens in the prostate gland. Structurally, TFM-4AS-1 is a 4-azasteroid. A structurally related and more advanced version of TFM-4AS-1, MK-0773, was developed and pursued for potential pharmaceutical use.
YK-11 is a synthetic steroidal selective androgen receptor modulator (SARM). It is a gene-selective partial agonist of the androgen receptor (AR) and does not induce the physical interaction between the NTD/AF1 and LBD/AF2, which is required for full transactivation of the AR. The drug has anabolic activity in vitro in C2C12 myoblasts and shows greater potency than dihydrotestosterone (DHT) in this regard. It has been investigated as a potential treatment for sepsis-induced muscle wasting in animal studies.
LG-120907 is a nonsteroidal antiandrogen (NSAA) of the quinoline group which was developed by Ligand Pharmaceuticals along with selective androgen receptor modulators (SARMs) like LG-121071 and was never marketed. The drug is a high-affinity antagonist of the androgen receptor (AR) with a Ki value of 26 nM and has been found to inhibit growth of the ventral prostate and seminal vesicles in male rats without increasing circulating levels of luteinizing hormone or testosterone. However, this tissue selectivity has not been assessed in humans. LG-120907 is orally active and shows greater oral potency than the arylpropionamide NSAA flutamide.
The pharmacology of bicalutamide is the study of the pharmacodynamic and pharmacokinetic properties of the nonsteroidal antiandrogen (NSAA) bicalutamide. In terms of pharmacodynamics, bicalutamide acts as a selective antagonist of the androgen receptor (AR), the biological target of androgens like testosterone and dihydrotestosterone (DHT). It has no capacity to activate the AR. It does not decrease androgen levels and has no other important hormonal activity. The medication has progonadotropic effects due to its AR antagonist activity and can increase androgen, estrogen, and neurosteroid production and levels. This results in a variety of differences of bicalutamide monotherapy compared to surgical and medical castration, such as indirect estrogenic effects and associated benefits like preservation of sexual function and drawbacks like gynecomastia. Bicalutamide can paradoxically stimulate late-stage prostate cancer due to accumulated mutations in the cancer. When used as a monotherapy, bicalutamide can induce breast development in males due to its estrogenic effects. Unlike other kinds of antiandrogens, it may have less adverse effect on the testes and fertility.
RU-59063 is a nonsteroidal androgen or selective androgen receptor modulator (SARM) which was first described in 1994 and was never marketed. It was originally thought to be a potent antiandrogen, but subsequent research found that it actually possesses dose-dependent androgenic activity, albeit with lower efficacy than dihydrotestosterone (DHT). The drug is an N-substituted arylthiohydantoin and was derived from the first-generation nonsteroidal antiandrogen (NSAA) nilutamide. The second-generation NSAAs enzalutamide, RD-162, and apalutamide were derived from RU-59063.
A sex-hormonal agent, also known as a sex-hormone receptor modulator, is a type of hormonal agent which specifically modulates the effects of sex hormones and of their biological targets, the sex hormone receptors. The sex hormones include androgens such as testosterone, estrogens such as estradiol, and progestogens such as progesterone. Sex-hormonal agents may be either steroidal or nonsteroidal in chemical structure and may serve to either enhance, inhibit, or have mixed effects on the function of the sex hormone systems.
GSK2881078 is a drug which acts as a selective androgen receptor modulator (SARM). It was developed for the prevention of muscle wasting and sarcopenia in elderly people.
GTx-027 is a selective androgen receptor modulator (SARM) which was under development for or of potential interest in the treatment of breast cancer and stress urinary incontinence (SUI) but was never marketed. It is taken by mouth.
MK-4541 is a dual selective androgen receptor modulator (SARM) and 5α-reductase inhibitor (5α-RI) which has been of interest for the potential treatment of prostate cancer but has not been marketed at this time. It is intended for use by mouth.