Enobosarm

Ostarine, also known as MK-2866 or enobosarm, is a selective androgen receptor modulator (SARM). It has anabolic properties and as such is widely used in doping, accounting in 2021 for 25 % of the adverse analytical findings (AAF) among the class S1.2 "Other anabolic agents" of products banned by the World Anti-Doping Agency, to which it belongs. But in some cases, it can be responsible for an AAF following contamination. We report the case of an athlete who contaminated herself by exchanging body fluids while kissing her boyfriend, who took 25 mg per day of MK-2866 for 9 days prior to the athlete's AAF (urinary concentration evaluated at 13 ng/mL) without her knowledge...

BACKGROUND: The androgen receptor is a tumour suppressor in oestrogen receptor-positive breast cancer. The activity and safety of enobosarm, an oral selective androgen receptor modulator, was evaluated in women with oestrogen receptor (ER)-positive, HER2-negative, and androgen receptor (AR)-positive disease. METHODS: Women who were postmenopausal (aged ≥18 years) with previously treated ER-positive, HER2-negative, locally advanced or metastatic breast cancer with an Eastern Cooperative Oncology Group performance status of 0-2 were enrolled in a randomised, open-label, multicentre, multinational, parallel design, phase 2 trial done at 35 cancer treatment centres in nine countries...

Liver injury associated with selective androgen receptor modulators (SARMs) is an issue that has not been reported often. We report a case of a previously healthy 24-year-old male, who was referred to our hospital for severe jaundice with intense pruritus. He had previously taken the SARM Enobosarm (also known as Ostarine) for muscle-building purposes. Blood serum levels of total bilirubin exceeded 30 mg/dL with only a slight elevation of liver enzymes . Liver biopsy revealed isolated hepatocellular cholestasis (bland cholestasis) with limited inflammation or necrosis...

Background: RAD-140, one of the novel selective androgen receptor modulators (SARMs), has potent anabolic effects on bones and muscles with little androgenic effect. Despite the lack of approval for its clinical use, RAD-140 is readily accessible on the consumer market. Hepatotoxicity associated with the use of SARMs has only rarely been reported in the literature. Case Report: A 24-year-old male presented with a 2-week history of diffuse abdominal pain, scleral icterus, pruritus, and jaundice. Prior to presentation, he had been taking the health supplement RAD-140 for muscle growth for 5 weeks...

PURPOSE: Enobosarm (EN), a selective androgen receptor modulator and raloxifene (RAL), a selective estrogen receptor modulator, have been shown to improve bone tissue in osteoporotic males. The present study evaluated the effects of a combination therapy of EN and RAL on bone properties in orchiectomized rats compared to the respective single treatments. METHODS: Eight-month-old male Sprague-Dawley rats were either left intact (Non-Orx) or orchiectomized (Orx). The Orx rats were divided into four groups (n = 15 each): 1) Orx, 2) EN treatment (Orx + EN), 3) RAL treatment (Orx + RAL), 4) combined treatment (Orx + EN + RAL)...

Selective androgen receptor modulators (SARMs) are compounds that bind to androgen receptors and have similar anabolic properties to anabolic steroids. Unlike anabolic steroids, which bind to androgen receptors in many tissues all over the body, individual SARMs selectively bind androgen receptors in certain tissues, but not in others. This selectivity has attracted researchers due to the possibility of using SARMs for the potential benefits of androgen receptor stimulation, such as increased muscle mass and increased bone density, while minimizing the adverse effects, such as erythrocytosis and hepatotoxicity...

Ostarine (also known as enobosarm or Gtx-024) belongs to the selective androgen receptor modulators (SARMs). It is a substance with an aryl-propionamide structure, classified as a non-steroidal compound that is not subjected to the typical steroid transformations of aromatization and reduction by α5 reductase. Despite ongoing research on ostarine, knowledge about it is still limited. Earlier studies indicated that ostarine may affect the metabolism of muscle tissue, but this mechanism has not been yet described...

Anabolic steroids are well-known to cause liver injury, which may manifest with jaundice and elevated liver enzymes. Selective androgen receptor modulators (SARMs) have been developed to enhance muscle bulk without the side effects associated with exogenous androgen steroids. We report a case of significant cholestatic liver injury associated with a SARM, ostarine (enobosarm), similar to that associated with anabolic steroids. Liver injury from SARMs has not been reported frequently, and we speculate that this may be seen more often as the consumption of SARMs increases in the athletic market...

LESSONS LEARNED: The combination of enobosarm and pembrolizumab was well tolerated and showed a modest clinical benefit rate of 25% at 16 weeks. Future trials investigating androgen receptor-targeted therapy in combination with immune checkpoint inhibitors are warranted. BACKGROUND: Luminal androgen receptor is a distinct molecular subtype of triple-negative breast cancer (TNBC) defined by overexpression of androgen receptor (AR). AR-targeted therapy has shown modest activity in AR-positive (AR+) TNBC...

Enobosarm (ostarine, MK-2866, or GTx-024) is a non-steroidal selective androgen receptor modulator. This study evaluated the effect of various regimens of enobosarm (EN) on bone healing in an orchiectomized rat model for aged male osteoporosis and compared it to testosterone (T) treatment. Ninety eight-month-old male Sprague Dawley rats were either orchiectomized (Orx) or left intact (Non-Orx) and divided into groups (n = 15/group): (1) Non-Orx; (2) Orx; (3) Orx+T-th; (4) Orx+EN-th; (5) Orx+T-pr; and (6) Orx+EN-pr...

Ostarine, also known as S22 or MK2866 and enobosarm, is a selective androgen receptor modulator (SARM). It has high anabolic potency, in addition to limited androgenic effects. At this time, ostarine has no therapeutic use, but can be abused for performance-enhancing purposes using the oral route, at dosages of 10-25 mg per day. As the drug can easily be obtained via the Internet or some fitness centers, athletes and more and more amateurs can use it without undergoing the deleterious physiological side effects that are generally associated with testosterone-related compounds...

A simple and sensitive procedure for the quantification of two commonly abused aryl-propionamide-derived selective androgen receptor modulators (SARMs), namely S-4 (GTx-007, andarine) and S-22 (GTx-024, MK-2866, ostarine, enobosarm), has been described. Urine samples were prepared for analysis by means of a dispersive liquid-liquid microextraction using methanol and chloroform as dispersive and extracting solvents, respectively. Factors that might influence the extraction process as well as their optimum conditions were evaluated by Box-Benken and central composite designs...

Synthetic ligands of androgen receptor (AR) are a standard in the treatment of androgen deficiency. One of the effects of androgen deficiency is the disturbance in the homeostasis of lipid metabolism. Till date, there are no effective compounds developed to treat androgen deficiency without having any side effects. Nonsteroidal selective androgen receptor modulators (SARMs) are a promising solution for various clinical indications. In this study, we investigated the effect of ostarine (enobosarm), a nonsteroidal SARM, on the rat adipocyte metabolism using in vitro techniques...

Selective androgen receptor modulators (SARMs) have been proposed as therapeutics for women suffering from breast cancer, muscle wasting or urinary incontinence. The androgen receptor (AR) is expressed in the uterus but the impact of SARMs on the function of this organ is unknown. We used a mouse model to compare the impact of SARMs (GTx-007/Andarine®, GTx-024/Enobosarm®), Danazol (a synthetic androstane steroid) and dihydrotestosterone (DHT) on tissue architecture, cell proliferation and gene expression...

SAR studies on bicalutamide, enobosarm and enzalutamide analogues, functionalised with polyfluorinated groups, is presented. Among the novel bicalutamide and enobosarm derivatives synthesised, several displayed significantly improved in vitro anticancer activity, with IC50 values in the low micromolar range against four different prostate cancer cell lines (LNCaP, VCaP, DU-145 and 22Rv1), showing up to 48-fold increase in comparison with the parent structures. In particular, SF5 enobosarm analogues were found to be most potent compounds, full AR antagonists and with favourable ADME properties...

BACKGROUND: Cachexia is a multisystem syndrome characterized by weight loss, anorexia, loss of muscle mass, systemic inflammation, insulin resistance, and functional decline. Management of cachexia involves addressing multiple underlying biological mechanisms. Previous review on pharmacological management of cancer cachexia identified progestins and corticosteroids as effective agents for treatment of cachexia. However, to date no consensus exists on a single effective or standard treatment for management of cachexia...

PURPOSE OF REVIEW: Randomized clinical trials of cancer cachexia interventions are based on the premise that an increase in the muscle mass of patients is associated with consequent improvements in muscle function, and ultimately, quality of life. However, recent trials that have succeeded in demonstrating increases in lean body mass have been unable to show associated increases in patient physical function. In this review, we examine the potential causes for this lack of association between muscle mass and function in cancer cachexia, paying particular attention to those factors that may be at play when using body composition analysis techniques involving cross-sectional imaging...

INTRODUCTION: Muscle wasting has detrimental effects, including increased mortality. Identifying patients at risk can guide treatment efforts. METHODS: POWER 1 and 2 were randomized, double-blind, placebo-controlled, multinational phase III trials that studied 600 patients with lung cancer at the start of chemotherapy; the studies' aim was to assess the efficacy of enobosarm on prevention and treatment of muscle loss. We performed a secondary analysis restricted to the control group, using a cumulative logit model for ordinal outcome to determine which baseline characteristics predicted physical and functional loss during chemotherapy...

Prostate cancer often develops antiandrogen resistance, possibly via androgen receptor (AR) mutations, which change antagonists to agonists. Novel therapies with increased anticancer activity, while overcoming current drug resistance are urgently needed. Enobosarm has anabolic effects on muscle and bone while having no effect on the prostate. Here, we describe the activity of novel chemically modified enobosarm analogues. The rational addition of bis -trifluoromethyl groups into ring B of enobosarm, profoundly modified their activity, pharmacokinetic and tissue distribution profiles...

This article highlights the updates from preclinical and clinical studies into the field of wasting disorders that were presented at the 10th Cachexia Conference held in Rome, Italy, in December 2017. This year's conference saw some interesting results of larger-scale studies and clinical trials and new therapeutic targets. Herein, we summarize the biological and clinical significance of different markers and new diagnostic tools and cut-offs for the detection of skeletal muscle wasting, including micro RNAs, the ubiquitin-proteasome system, mTOR signalling, news in body composition analysis including the D3-creatine dilution method, and new biomarkers...