Search

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. Prophylaxis (Pr) treatments were applied immediately after Orx for up to 18 weeks. Therapy (Th) treatments were applied 12 weeks after Orx for up to 6 weeks. Bilateral tibia osteotomy with plate osteosynthesis was performed 12 weeks after Orx in all groups. EN and T were mixed with the diet; the daily dosage was 0.35 ± 0.06 and 41 ± 8 mg/kg BW, respectively. Both T treatments improved bone healing by increasing callus volume and area, bone volume and density, and cortical width; they had no effect on prostate or levator ani weight. EN-pr increased the callus area and callus density and decreased cortical density, but increased prostate weight. The effect of T-pr and T-th on bone was stronger than EN-pr. EN-th affected bone healing negatively by reducing callus density and area and delaying osteotomy bridging. Levator ani weight was increased in both EN groups. EN treatment after fracture is not advisable in aged males. EN-pr treatment as a therapy for bone healing in men could be further investigated; endocrinological side effects must be closely monitored. Electronic supplementary material The online version of this article (10.1007/s00223-020-00751-x) contains supplementary material, which is available to authorized users.

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. Since 2008, the World Anti-Doping Agency (WADA) has prohibited SARMs at-all-times in the category of "other anabolic agents" under section S1.2 of the WADA List. In a case of trafficking/abuse, ostarine was identified in nail (subject 1) and hair (subject 2) by LC/HRMS after incubation of 50 mg of matrix in a pH 9.5 buffer, followed by extraction with organic solvents. The drug was quantitated by LC-MS/MS. Ostarine tested positive at 61 pg/mg (toenails) and 111 pg/mg (fingernails) for subject 1. Ostarine was present at 146, 168, 93, and 101 pg/mg in the 4 × 3 cm hair sections of subject 2, clearly demonstrating long-term use.

Introduction: Hormonal agents remain the most effective therapies for estrogen receptor positive (ER+) HER2- breast cancer. The androgen receptor (AR) is the most highly expressed steroid receptor found in up to 95% of ER+ breast cancer patients. Androgen agonists have antiproliferative activity in ER+ breast cancer and have been used in treatment, however their lack of availability and virilizing side effects have limited their use. Enobosarm is a non-steroidal tissue-selective AR modulator that that is being developed for AR targeted treatment of ER+/AR+ breast cancer. Methods: An international, Phase 2, open label, parallel design, randomized study was conducted in 136 patients (pts) to investigate the efficacy and safety of enobosarm in postmenopausal women with metastatic ER+/AR+ breast cancer that progressed on previous endocrine therapy. Pts were randomized to receive 9 mg (n=72) or 18 mg (n=64) of oral daily enobosarm. The primary endpoint was clinical benefit rate (CBR) at 24 weeks (defined as CR, PR or SD) by RECIST 1.1. Secondary endpoints included objective response rate, best overall response rate (BOR), progression free survival (PFS), duration of clinical benefit. Results: The study population consisted of heavily pre-treated pts with a mean of 4 (range 1-6) prior hormone therapies and >90% receiving one prior course of chemotherapy. Median age was 60.8 years (35-83) for 9 mg and 62.1 (42-81) for the 18 mg cohort. AR positivity was centrally confirmed in 73.6% and 81.2% in the 9 and 18 mg cohorts, respectively. Efficacy: In the evaluable pts, 50 in the 9 mg arm and 52 in the 18 mg arm (AR confirmed), 32% of the 9mg cohort met the primary endpoint of CBR at 24 weeks (95% CI, 19.5%; 46.7%) and 29% (95% CI, 17.1%; 43.1%) in the 18 mg cohort. The BOR was 2 CRs, 10 PRs in the 9 mg and 3 CRs,7 PRs in the 18 mg group by central review. Median PFS was 5.6 (2.9 to 27.5) and 4.2 (2.8 to 11) months (mo) in the 9 mg and 18 mg groups. The median duration of treatment was 4.0 months (0.23-30.3 months) in the 9 mg group and 3.8 months (0.5-16.7 months) in the 18 mg group. At the time the study was terminated, the median duration of clinical benefit was not reached (NR) in the 9 mg group (range 8.2 mo to NR) and 14.1 mo (range 11.0 to 16.5) in the 18 mg group. QOL: Using a standardized instrument of generic health status (EQ-5D), a significant percentage of pts reported improvement in measurements including mobility (40%, 50%), anxiety/depression (50%, 29%) and pain discomfort (50%, 31%) for the 9 and 18 mg groups, respectively. Drug related severe adverse events (SAEs) (Grades 3-4) were observed in 6 (8.0%) at the 9 mg and 10 (16.4%) at the 18 mg dose. The SAEs (Grade 3-4) attributed to the study drug by the site investigator were for the 9 mg group: fatigue (1), elevated transaminases (2), headache (1), hypercalcemia (2) and anemia (1). For the 18 mg group the drug attributable SAEs (Grade 3-4) were: dry mouth (1), increased aminotransferase (2), decreased white blood cell count (1), fatigue (2), hypercalcemia (1), decreased appetite (1), headache (1), tumor flare (2), agitation (1), lymphadenopathy (1) and acute kidney injury (1). Conclusions: In this Phase 2 parallel design study, enobosarm (9 mg and 18 mg) has significant clinical activity and was well tolerated in heavily pretreated patients with ER+/AR+ metastatic breast cancer. Given the limited options of hormonal therapy for metastatic ER+ breast cancer, enobosarm merits further clinical development in a Phase 3 clinical program as an AR targeted treatment for metastatic ER+AR+ breast cancer. Citation Format: Carlo Palmieri, Hannah Linden, Stephen Birrell, Elgene Lim, Lee S Schwartzberg, Hope S Rugo, Patrick Cobb, Kirti Jain, Charles Vogel, Joyce A O’Shaughnessy, Robert H Getzenberg, Mitchell S Steiner, Adam Brufsky, Beth Overmoyer. Efficacy and safety of enobosarm, a selective androgen receptor modulator, to target AR in women with advanced ER+/AR+ breast cancer - final results from an international Phase 2 randomized study [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD8-10.

The class of selective androgen receptor modulators (SARMs) has been the subject of intense and dedicated clinical research over the past two decades. Potential therapeutic applications of SARMs are manifold and focus particularly on the treatment of conditions manifesting in muscle loss such as general sarcopenia, cancer-associated cachexia, muscular dystrophy, etc. Consequently, based on the substantial muscle- and bone-anabolic properties of SARMs, these agents constitute substances with significant potential for misuse in sport and have therefore been added to the Word Anti-Doping Agency's (WADA's) Prohibited List in 2008. Since then, numerous adverse analytical findings have been reported for various different SARMs, which has underlined the importance of proactive and preventive anti-doping measures concerning emerging drugs such as these anabolic agents, which have evidently been misused in sport despite the fact that none of these SARMs has yet received full clinical approval. In this review, analytical data on SARMs generated in the context of research conducted for sports drug testing purposes are summarized and state-of-the-art test methods aiming at intact drugs as well as diagnostic urinary metabolites are discussed. Doping control analytical approaches predominantly rely on chromatography hyphenated to mass spectrometry, which have allowed for appropriately covering the considerable variety of pharmacophores present in SARMs such as the non-steroidal representatives ACP-105, BMS-564929, GLPG0492 (DT-200), LG-121071, LGD-2226, LGD-4033/VK 5211, ostarine/enobosarm, RAD-140, S-40503, etc. as well as steroidal compounds such as MK-0773 and YK-11.

Most advanced cancer patients suffer loss of appetite (anorexia) and loss of weight. Despite the fact that cancer anorexia and weight loss are associated with a poor prognosis and detract from quality of life, no interventions have been demonstrated to palliate this syndrome in its entirety, particularly in patients with treatment-refractory malignancies. Recently, two registration trials – one with anamorelin and another with enobosarm -- failed to reach their primary endpoints, thus raising questions. Were both these agents ineffective? Alternatively, did study design issues compromise the ability of these trials to identify effective agents? Thus, this review is timely insofar it serves as an introduction to study design, offers guidance on how to test promising agents for cancer anorexia/weight loss, and provides advice for overcoming trial design obstacles.

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. After extraction, the analytes were quantified by UHPLC-MS/MS. The proposed procedure was validated on human urine samples. As a result, for both SARMs the detection limits were observed at 0.05 ng/mL and calibration curves were linear in the concentration range of 0.25-50 ng/mL with the coefficient of determination of 0.998.

1020 Background: The AR is expressed in up to 90% of ER+ breast cancer where it acts as a tumor suppressor. Historically, therapy with synthetic androgens had efficacy, but virilizing side effects and toxicity limited their use. Enobosarm is a selective AR activating agent that does not cause masculinization and has positive attributes such as promotion of bone and improvement of physical function. In a phase 2 study, correlation between the degree of AR staining and antitumor activity in AR+/ER+ patients with metastatic breast cancer (MBC) was examined. Methods: A phase 2, open label, parallel design randomized study was conducted in 136 patients to evaluate the efficacy and safety of enobosarm in heavily pretreated women with AR+/ER+ MBC. Patients were randomized to 9 mg (n=72) or 18 mg (n=64) of oral daily enobosarm. AR expression (%AR nuclei staining) in breast cancer samples was determined centrally by immunohistochemistry. The correlation between %AR staining and clinical outcomes was examined with a focus on the 9mg dose, selected for the phase 3 study and the optimal %AR staining established. Results: Tumor objective outcomes correlated with percent AR staining (Table). Further, using a 40% AR staining cutoff in patients with measurable disease, the clinical benefit rate (CBR) for ≥40% AR is 80% and

Introduction: In breast cancer the androgen receptor (AR) is the most abundantly expressed steroid receptor with 75-95% of estrogen receptor (ER)-positive and 40-70% of ER-negative breast cancers expressing the AR. Historically, advanced breast cancer has been treated with androgens, resulting in significant clinical response. However, the use of steroidal androgens fell from favor as a result of their virilizing side effects. Nonsteroidal, tissue selective androgen receptor modulators (SARMs) will provide a novel targeted approach to exploit the therapeutic benefits of androgens in breast cancer. Aims: To test the effects of enobosarm (a first-in-class SARM) and enzalutamide (AR antagonist) on the growth of patient-derived breast cancer xenografts (PDX) and to discern the mechanism of action of AR-targeted therapies in AR-positive breast cancer. Materials and Methods: AR-positive PDXs with varying receptor expression (ER, progesterone receptor (PR), and HER2) were implanted in immunecompromised mice. Mice carrying PDXs were treated with vehicle, 10 mg/kg/day (mpk) enobosarm (GTx, Inc., Memphis, TN), or 20 mpk enzalutamide (Medivation Inc.), orally. Tumor volume was measured twice or thrice weekly. Tumors that received enobosarm were further analyzed to determine the mechanism of action. Results: Enobosarm significantly (p Conclusion: These results indicate that AR-positive breast cancers are highly heterogeneous and that enobosarm has promise as novel targeted therapy to treat AR-positive breast cancer. Enobosarm is currently in phase II clinical trial in both ER-positive breast cancer and in TNBC patients. Citation Format: Narayanan R, Ponnusamy S, Fan M, Yang CH, Grimes BL, Fleming MD, Pritchard EF, Berry MP, Oswaks RM, Fine RE, Loiseau J-C, Schwartzberg LS, Pfeffer LM. Nonsteroidal, tissue selective androgen receptor modulator (SARM), enobosarm, reduces growth of androgen receptor-positive breast cancer in patient-derived preclinical models [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-12-06.

Cachexia and sarcopenia are conditions phenotypically characterized by muscle loss and represent a factor of poor prognosis, increasing patients' morbidity and mortality. Cachectic and sarcopenic patients often suffer from low quality of life, presenting lower muscle strength and appetite loss, which makes research on novel treatment strategies to ameliorate clinical response including patient's symptoms, the objective of scientific interest.This article covers recent developments in the area of cachexia and sarcopenia treatment and therapeutic interventions, targeting central nervous system involvement, key inflammatory and muscle-specific metabolic pathways.A number of promising agents have being evaluated, such as enobosarm, a selected androgen receptor modulator, and anamorelin, a ghrelin agonist which have been recently studied in phase III trials. These and other agents (i.e., infliximab, tocilizumab, MABp1, bimagrumab) have shown significant impact on reversal of skeletal muscle loss, but limited effect on physical function. In the last few years advancement in the number and type of potential treatments for cachexia and sarcopenia have been obtained and we have now available more data on measurable effects of several drugs on patients' nutritional and metabolic parameters and outcomes.

Currently under development for therapeutic purposes in human medicine, non-steroidal selective androgen receptor modulators (non-steroidal SARMs) are also known to impact growth associated pathways. As such, they present a potential for abuse in sports and food-producing animals as interesting alternative anabolic substances. Forbidden since 2008 by the World Anti-Doping Agency (WADA) these compounds are however easily available and could be (mis)used in livestock production as growth promoters. To prevent such practices, dedicated analytical strategies have to be developed for specific and sensitive detection of these compounds in biological matrices. Using an innovative analytical platform constituted of supercritical fluid chromatography coupled to ion mobility-mass spectrometry, the present study enabled efficient separation and identification in urine of 4 of these drugs (andarine, bicalutamide, hydroxyflutamide, and enobosarm) in accordance with European Union criteria (Commission Decision 2002/657/EC). Besides providing information about compounds structure and behaviour in gas phase, such a coupling enabled reaching low limits of detection (LOD

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.

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. The aim of this systematic review is to determine the effectiveness of pharmacological treatments used to manage cachexia among adult cancer patients. Methods We performed literature searches of PubMed (NLM), Embase (Ovid), and Medline(Ovid) to identify clinical trials focused on pharmacological management of cancer cachexia among adult cancer patients from 2004 to 2018. Three reviewers screened a random selection of abstracts to measure for interrater reliability. After this step, each screener screened two-thirds of all abstracts and 177 studies were identified for full text review. The primary outcome was impact of pharmacological management on change in either weight or lean body mass in cancer patients. Results We identified 19 articles (representing 20 RCTs) that focused on pharmacological management of cancer cachexia. Agents showing promising results included Anamorelin and Enobosarm. Anamorelin at 50 or 100 mg per day for 12 weeks showed a consistent benefit across all studies and resulted in significant improvement in weight as compared to baseline among cancer patients. Enobosarm at 1 and 3 mg per day was also effective in improving lean body mass and QOL symptoms among advancer stage cancer patients. Finally, use of combination agents provide evidence for targeting multiple pathways underlying cachexia mechanism to achieve maximum benefit. No agents showed functional improvement in cancer patients. Conclusion Anamorelin as a single agent shows promising results in improving cachexia related weight loss among cancer patients. Further research on combination therapies may be helpful to address critical gaps in cachexia management. Electronic supplementary material The online version of this article (10.1186/s12885-018-5080-4) contains supplementary material, which is available to authorized users.

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. Moreover, we propose a new population-specific model for the relationship between muscle mass and physical function in patients with cancer cachexia.RECENT FINDINGS: The ROMANA 1 and 2 trials of anamorelin (a novel ghrelin agonist) and the POWER 1 and 2 trials of enobosarm (a selective androgen receptor modulator) were able to demonstrate improvements in patient lean body mass, but not the functional co-primary endpoints of handgrip strength and stair climb power, respectively. We report similar confirmatory findings in other studies, and describe potential reasons for these observations.SUMMARY: The relationship between muscle mass and muscle function is complex and unlikely to be linear. Furthermore, the relationship is influenced by the techniques used to assess nutritional endpoints [e.g. computed tomography (CT)]; the nature of the chosen physical function outcome measures; and the sex and severity of the recruited cachectic patients. Such factors need to be considered when designing intervention trials for cancer cachexia with functional endpoints.

PurposeThe common colon-26 mouse (C-26) model of experimental cachexia mimics recent late stage clinical failures of anabolic anti-cachexia therapy, and does not respond to the anabolic selective androgen receptor modulator (SARM) GTx-024. Based on the demonstrated anti-cachectic efficacy of the histone deacetylase inhibitor (HDACi) AR-42 in this model, we hypothesized that combined SARM/AR-42 would provide improved anti-cachectic efficacy.DesignIn the C-26 model, we determined a reduced efficacious dose of AR-42 which was combined with anabolic SARM therapy and evaluated for anti-cachectic efficacy. The effects of treatment and tumor burden on anabolic and catabolic signaling occurring in skeletal muscle were characterized using muscle performance parameters and RNA-seq.ResultsAnabolic anti-cachexia therapy with diverse androgens had no impact on cachectic outcomes in the C-26 model. A reduced dose of the HDACi AR-42 alone provided limited anti-cachectic benefits, but when combined with the SARM GTx-024, significantly improved bodyweight (pConclusionsCachectic signaling in the C-26 model is comprised of catabolic signaling insensitive to anabolic GTx-024 therapy and a blockade of GTx-024-mediated anabolic signaling. AR-42 treatment mitigates catabolic gene activation and restores anabolic responsiveness to GTx-024. Combining GTx-024, a clinically established anabolic therapy, with a low dose of AR-42, a clinically evaluated HDACi, represents a promising approach to improve anabolic response in cachectic patient populations.

Cancer cachexia is a syndrome that impairs the quality of life and overall survival of patients, and thus the effectiveness of anticancer agents. There are no effective therapies for cancer cachexia due to the complexity of the syndrome, and insufficient knowledge of its pathogenesis results in difficulty establishing appropriate animal models. Previously, promising results have been obtained in clinical trials using novel agents including the ghrelin receptor agonist anamorelin, and the selective androgen receptor modulator (SARM) enobosarm to treat cachexia in patients with cancer. The present study examined the pharmacological effects of SARM-2f, a novel non-steroidal small molecule SARM, in animal models. SARM-2f increased body and skeletal muscle weight without significantly increasing the weight of the seminal vesicles or prostates of the castrated male rats. In the mice with tumor necrosis factor α-induced cachexia, SARM-2f and TP restored body weight, carcass weight, and food consumption rate. In the C26 and G361 cancer cachexia animal models, body and carcass weight, lean body mass, and the weight of the levator ani muscle were increased by SARM-2f and TP treatments. Tissue selectivity of SARM-2f was also observed in these animal models. The results demonstrate the anabolic effects of SARM-2f in a cytokine-induced cachexia model and other cancer cachexia models, and suggest that SARM-2f may be a novel therapeutic option for cachexia in patients with cancer.

This article highlights preclinical and clinical studies in the field of wasting disorders that were presented at the 7th Cachexia Conference held in Kobe, Japan, in December 2013. This year, the main topics were the development of new methods and new biomarkers in the field of cachexia and wasting disorders with particular focus on inflammatory pathways, growth differentiation factor-15, myostatin, the ubiquitin proteasome-dependent pathway, valosin and the regulation of ubiquitin-specific protease 19 that is involved in the differentiation of myogenin and myosin heavy chain. This article presents highlights from the development of drugs that have shown potential in the treatment of wasting disorders, particularly the ghrelin receptor agonist anamorelin, the myostatin antagonist REGN1033, the selective androgen receptor modulators enobosarm and TEI-E0001, and the anabolic catabolic transforming agent espindolol. In addition, novel data on the prevalence and detection methods of muscle wasting/sarcopenia are presented, including the D3-creatine dilution method and several new biomarkers.

ABSTRACT Muscle loss and wasting occurs with aging and in multiple disease states including cancer, heart failure, chronic obstructive pulmonary disease, end-stage liver disease, end-stage renal disease and HIV. Cachexia is defined as a multifactorial syndrome that is associated with anorexia, weight loss and increased catabolism, with increased morbidity and mortality. Currently no therapy is approved for the treatment or prevention of cachexia. Different treatment options have been suggested but many have proven to be ineffective or associated with adverse events. Nonsteroidal selective androgen receptor modulators (SARMs) are a new class of anabolic agents that bind the androgen receptor and exhibit tissue selectivity. Enobosarm (GTx-024, S-22) is a recently developed SARM, developed by GTx, Inc. (TN, USA), which has been tested in Phase I, II and III trials with promising results in terms of improving lean body mass and measurements of physical function and power. Enobosarm has received fast track designation by the US FDA and results from the Phase III trials POWER1 and POWER2 will help determine approval for use in the prevention and treatment of muscle wasting in patients with non-small-cell lung cancer. This article provides an introduction to enobosarm as a new therapeutic strategy for the prevention and treatment of cachexia. A review of the literature was performed using search terms ‘cachexia’, ‘sarcopenia’, ‘SARM’, ‘enobosarm’ and ‘GTx-024’ in September 2013 using multiple databases as well as online resources.

Sarcopenia and cachexia are significant medical problems with a high disease-related burden in cardiovascular illness. Muscle wasting and weight loss are very frequent particularly in chronic heart failure and they relate to poor prognosis. Although clinically largely underestimated, the fields of cachexia and sarcopenia are of great relevance to cardiologists. In cachexia and sarcopenia a significant number of research publications related to basic science questions of muscle wasting and lipolysis were published between 2010 and 2012. Recently, the two processes of muscle wasting and lipolysis were found to be closely linked. Treatment research in pre-clinical models involves studies on a number of different therapeutic entities, including ghrelin, selective androgen receptor modulators (SARMs), as well as drugs targeting myostatin or melanocortin-4. In the human setting, studies using enobosarm (a SARM) and anamorelin (ghrelin) are in phase III. The last 3 years have seen significant efforts to define the field using consensus statements. In the future, these definitions should also be considered for guidelines and treatment trials in cardiovascular medicine. The current review aims to summarize important information and development in the fields of muscle wasting, sarcopenia and cachexia, focusing on findings in cardiovascular research, in order for cardiologists to have a better understanding of the progress in this still insufficiently known field.

Muscle wasting in cancer is a common and often occult condition that can occur prior to overt signs of weight loss and before a clinical diagnosis of cachexia can be made. Muscle wasting in cancer is an important and independent predictor of progressive functional impairment, decreased quality of life, and increased mortality. Although several therapeutic agents are currently in development for the treatment of muscle wasting or cachexia in cancer, the majority of these agents do not directly inhibit muscle loss. Selective androgen receptor modulators (SARMs) have the potential to increase lean body mass (LBM) and hence muscle mass, without the untoward side effects seen with traditional anabolic agents. Enobosarm, a nonsteroidal SARM, is an agent in clinical development for prevention and treatment of muscle wasting in patients with cancer (POWER 1 and 2 trials). The POWER trials are two identically designed randomized, double-blind, placebo-controlled, multicenter, and multinational phase 3 trials to assess the efficacy of enobosarm for the prevention and treatment of muscle wasting in subjects initiating first-line chemotherapy for non-small-cell lung cancer (NSCLC). To assess enobosarm's effect on both prevention and treatment of muscle wasting, no minimum weight loss is required. These pivotal trials have pioneered the methodological and regulatory fields exploring a therapeutic agent for cancer-associated muscle wasting, a process hereby described. In each POWER trial, subjects will receive placebo (n = 150) or enobosarm 3 mg (n = 150) orally once daily for 147 days. Physical function, assessed as stair climb power (SCP), and LBM, assessed by dual-energy X-ray absorptiometry (DXA), are the co-primary efficacy endpoints in both trials assessed at day 84. Based on extensive feedback from the US Food and Drug Administration (FDA), the co-primary endpoints will be analyzed as a responder analysis. To be considered a physical function responder, a subject must have ≥10 % improvement in physical function compared to baseline. To meet the definition of response on LBM, a subject must have demonstrated no loss of LBM compared with baseline. Secondary endpoints include durability of response assessed at day 147 in those responding at day 84. A combined overall survival analysis for both studies is considered a key secondary safety endpoint. The POWER trials design was established with extensive clinical input and collaboration with regulatory agencies. The efficacy endpoints are a result of this feedback and discussion of the threshold for clinical benefit in patients at risk for muscle wasting. Full results from these studies will soon be published and will further guide the development of future anabolic trials. Clinical Trial ID: NCT01355484. https://clinicaltrials.gov/ct2/show/NCT01355484 , NCT01355497. https://clinicaltrials.gov/ct2/show/NCT01355497?term=g300505rank=1 .

GTx-024 (also known as enobosarm) is a first in class selective androgen receptor modulator being developed for diverse indications in oncology. Preclinical studies of GTx-024 supported the evaluation of several potential drug-drug interactions in a clinical setting. A series of open-label Phase I GTx-024 drug-drug interaction studies were designed to interrogate potential interactions with CYP3A4 inhibitor (itraconazole), a CYP3A4 inducer (rifampin), a pan-UGT inhibitor (probenecid), a CYP2C9 substrate (celecoxib) and a BCRP substrate (rosuvastatin). The plasma pharmacokinetics of GTx-024, its major metabolite (GTx-024 glucuronide), and each substrate were characterized in detail. Itraconazole administration had no effect on GTx-024 pharmacokinetics. Likewise, GTx-024 administration did not significantly change the pharmacokinetics of celecoxib or rosuvastatin. Rifampin administration had the largest impact on GTx-024 pharmacokinetics of any co-administered agent and reduced the maximal plasma concentration (Cmax) by 23 % and the area under the curve (AUC∞) by 43 %. Probenecid had a complex interaction with GTx-024 whereby both GTx-024 plasma levels and GTx-024 glucuronide plasma levels (AUC∞) were increased by co-administration of the UGT inhibitor (50 and 112 %, respectively). Overall, GTx-024 was well tolerated and poses very little risk of generating clinically relevant drug-drug interactions.

Androgens increase skeletal muscle mass, but their clinical use is hampered by a lack of tissue selectivity and subsequent side effects. Selective androgen receptor modulators elicit muscle-anabolic effects while only sparingly affecting reproductive tissues. The selective androgen receptor modulator, GTx-024 (enobosarm), is being investigated for cancer cachexia, sarcopenia, and muscle wasting diseases. Here we investigate the role of muscle androgen receptor (AR) in the anabolic effect of GTx-024. In mice lacking AR in the satellite cell lineage (satARKO), the weight of the androgen-sensitive levator ani muscle was lower but was decreased further upon orchidectomy. GTx-024 was as effective as DHT in restoring levator ani weights to sham levels. Expression of the muscle-specific, androgen-responsive genes S-adenosylmethionine decarboxylase and myostatin was decreased by orchidectomy and restored by GTx-024 and DHT in control mice, whereas the expression was low and unaffected by androgen status in satARKO. In contrast, insulin-like growth factor 1Ea expression was not different between satARKO and control muscle, decreased upon castration, and was restored by DHT and GTx-024 in both genotypes. These data indicate that GTx-024 does not selectively modulate AR in the satellite cell lineage and that cells outside this lineage remain androgen responsive in satARKO muscle. Indeed, residual AR-positive cells were present in satARKO muscle, coexpressing the fibroblast-lineage marker vimentin. AR positive, muscle-resident fibroblasts could therefore be involved in the indirect effects of androgens on muscle. In conclusion, both DHT and GTx-024 target AR pathways in the satellite cell lineage, but cells outside this lineage also contribute to the anabolic effects of androgens.

This review highlights selective androgen receptor modulators (SARMs) as emerging agents in late-stage clinical development for the prevention and treatment of muscle wasting associated with cancer.Muscle wasting, including a loss of skeletal muscle, is a cancer-related symptom that begins early in the progression of cancer and affects a patient's quality of life, ability to tolerate chemotherapy, and survival. SARMs increase muscle mass and improve physical function in healthy and diseased individuals, and potentially may provide a new therapy for muscle wasting and cancer cachexia. SARMs modulate the same anabolic pathways targeted with classical steroidal androgens, but within the dose range in which expected effects on muscle mass and function are seen androgenic side-effects on prostate, skin, and hair have not been observed. Unlike testosterone, SARMs are orally active, nonaromatizable, nonvirilizing, and tissue-selective anabolic agents.Recent clinical efficacy data for LGD-4033, MK-0773, MK-3984, and enobosarm (GTx-024, ostarine, and S-22) are reviewed. Enobosarm, a nonsteroidal SARM, is the most well characterized clinically, and has consistently demonstrated increases in lean body mass and better physical function across several populations along with a lower hazard ratio for survival in cancer patients. Completed in May 2013, results for the Phase III clinical trials entitled Prevention and treatment Of muscle Wasting in patiEnts with Cancer1 (POWER1) and POWER2 evaluating enobosarm for the prevention and treatment of muscle wasting in patients with nonsmall cell lung cancer will be available soon, and will potentially establish a SARM, enobosarm, as the first drug for the prevention and treatment of muscle wasting in cancer patients.

Purpose of review This article highlights recent developments in the area of cancer cachexia and therapeutic interventions. Recent findings Therapeutic interventions in cancer cachexia have been guided by clinical studies focused on the central role of muscle and the increased use of CT imaging to measure the impact of skeletal muscle loss on clinical outcomes. At the translational level, a number of different model systems have emphasized the importance of blockade of tumor-induced inflammation and its potential impact on reversing the cachexia phenotype, including FN14, a receptor in the TNF pathway, as well as the parathyroid hormone-related protein. Clinical studies continue to demonstrate the importance of nutrition and exercise as part of a multimodality approach. Although a number of promising agents are being evaluated, both enobosarm, a selected androgen receptor modulator, and anamorelin, a ghrelin agonist have completed phase III trials. Both agents have shown significant impact on reversal of skeletal muscle loss, but inconsistent effect on physical function improvement. Anamorelin also has a positive effect on appetite and weight gain. Summary Further analysis of these studies, along with regulatory guidance, will be critical in the further development of these and other promising agents in the clinical management of patients with cancer cachexia.

Sarcopenia and cachexia are significant medical problems with a high disease related burden in cardiovascular illness. Muscle wasting and weight loss are very frequent particularly in chronic heart failure and they relate to poor prognosis. Although clinically largely underestimated, the fields of cachexia and sarcopenia are of great relevance to cardiologists. In cachexia and sarcopenia a significant number of research publications related to basic science questions of muscle wasting and lipolysis were published between 2010 and 2012. Recently, the two processes of muscle wasting and lipolysis were found to be closely linked. Treatment research in pre-clinical models involves studies on a number of different therapeutic entities, including ghrelin, selective androgen receptor modulators (SARMs), as well as drugs targeting myostatin or melanocortin-4. In the human setting, studies using enobosarm (a SARM) and anamorelin (ghrelin) are in phase III. The last 3 years has seen significant efforts to define the field using consensus statements. In the future, these definitions should also be considered for guidelines and treatment trials in cardiovascular medicine. The current review aims to summarize important information and development in the fields of muscle wasting, sarcopenia and cachexia focussing on findings in cardiovascular research, in order for cardiologists to have a better understanding of the progress in the still not well enough known field.

9618 Background: Cancer induced muscle wasting is a selective and progressive cancer related symptom that begins early in the course of malignancy. Greater than 50% of NSCLC patients have muscle wa...

568 Background: The androgen receptor (AR) is the most highly expressed steroid receptor in breast cancer (BC) with 75-95% of estrogen receptor positive (ER+) and 50% of ER negative BCs expressing ...

e19100 Background: Although muscle wasting and cancer cachexia occur in > 80% of patients with advanced cancer, few well-powered scientifically-based trials have been conducted. Using enobosarm, a novel SARM, we have now enlisted 650 patients (pts) with advanced NSCLC in two phase III trials. Recent studies indicate major advantages for supportive care in NSCLC at chemotherapy initiation (Temel, NEJM 2010).This presentation examines the feasibility of pt enlistment at chemo initiation, the major characteristics of these pts and trial design for the prevention and treatment of muscle wasting. Methods: Both double-blind, placebo-controlled, international trials evaluate the effect of enobosarm in NSCLC. ˜300 pts with stage III or IV NSCLC were randomized in each trial at initiation of first-line chemo to receive additionally enobosarm or placebo for 5 months. Pts were males and postmenopausal females ≥30 years, ECOG ≤1. First line chemo: a platinum + taxane (Power 1) or platinum + non-taxane (Power 2). Co-primary endpoints at Day 84 are physical function assessed by stair climb power (SCP) and lean body mass (LBM) by DXA. Baseline characteristics are available on 634 pts (98%), as in the Table. Results: See Table. Conclusions: These results indicate that it is feasible to enlist pts receiving first-line chemo in trials designed to prevent or treat muscle wasting and cachexia; their presenting characteristics are typical for NSCLC. Median weight loss at baseline was 5% even though weight loss was not required for study inclusion. LBM and SCP were lower than typically observed in healthy individuals indicating significant functional decline before starting chemo for NSCLC. These phase III trials will determine the effect of enobosarm on preventing and treating muscle wasting in NSCLC. Clinical trial information: NCT01355484 and NCT01355497. [Table: see text]

e19585 Background: Although cachexia has been defined as >5% weight loss, limited data exists on the prevention and treatment of muscle wasting prior to a patient becoming cachectic. Cancer induced muscle wasting can begin early in the course of a patient’s malignancy resulting in decline in physical function and other detrimental clinical consequences including less tolerability to chemotherapy, worse outcomes, and shorter survival - underscoring the importance of diagnosing and treating this condition at an early stage. Methods: We conducted a randomized, double blind, placebo controlled, multi-center study to evaluate the effect of enobosarm on physical function and muscle wasting in cancer patients. Subjects (n=159) were randomized to oral enobosarm or placebo for 16 weeks. Subjects were males >45y and postmenopausal females, with ≥2% weight loss in the 6 months prior to randomization and diagnosed with NSCLC, colorectal cancer, non-Hodgkin’s lymphoma, chronic lymphocytic leukemia or breast cancer. We report on changes in physical function based on weight loss of < or ≥5%in the 6 months prior to randomization. Results: 103 subjects (MITT) had physical function assessed by stair climb at baseline and week 16 with 24% losing

e19582 Background: Hypogonadism has been associated with weight loss and poor outcomes in cancer patients. Up to 50% of males with advanced cancer are hypogonadal at presentation or during the course of treatment. Wasting in cancer patients has also been associated with a decline in physical function and performance status and has major public health significance. We conducted a Phase IIb randomized, double blind, placebo controlled, multi-center study to evaluate the effect of enobosarm on muscle wasting and physical function in cancer patients. Methods: Patients (n=159) were randomized to oral enobosarm (1 or 3 mg) or placebo daily for 16 wks. Patients were males >45 y and postmenopausal females, had ≥2% weight loss in the 6 mths prior to randomization, BMI

BACKGROUND: Cachexia, also known as muscle wasting, is a complex metabolic condition characterized by loss of skeletal muscle and a decline in physical function. Muscle wasting is associated with cancer, sarcopenia, chronic obstructive pulmonary disease, end-stage renal disease, and other chronic conditions and results in significant morbidity and mortality. GTx-024 (enobosarm) is a nonsteroidal selective androgen receptor modulator (SARM) that has tissue-selective anabolic effects in muscle and bone, while sparing other androgenic tissue related to hair growth in women and prostate effects in men. GTx-024 has demonstrated promising pharmacologic effects in preclinical studies and favorable safety and pharmacokinetic profiles in phase I investigation. METHODS: A 12-week double-blind, placebo-controlled phase II clinical trial was conducted to evaluate GTx-024 in 120 healthy elderly men (60 years of age) and postmenopausal women. The primary endpoint was total lean body mass assessed by dual energy X-ray absorptiometry, and secondary endpoints included physical function, body weight, insulin resistance, and safety. RESULTS: GTx-024 treatment resulted in dose-dependent increases in total lean body mass that were statistically significant (P 0.001, 3 mg vs. placebo) and clinically meaningful. There were also significant improvements in physical function (P = 0.013, 3 mg vs. placebo) and insulin resistance (P = 0.013, 3 mg vs. placebo). The incidence of adverse events was similar between treatment groups. CONCLUSION: GTx-024 showed a dose-dependent improvement in total lean body mass and physical function and was well tolerated. GTx-024 may be useful in the prevention and/or treatment of muscle wasting associated with cancer and other chronic diseases.