Effect of ghrelin and anamorelin (ONO-7643), a selective ghrelin receptor agonist, on tumor growth in a lung cancer mouse xenograft model

Anamorelin for the Treatment of Cancer Anorexia-Cachexia Syndrome

PURPOSE OF REVIEW

The following review will highlight the development of anamorelin to treat cancer anorexia-cachexia syndrome (CACS) including the potential benefits, limitations, and future directions.

RECENT FINDINGS

Ghrelin, a 28-amino acid peptide hormone, is secreted by the stomach mucosa and regulates appetite, promotes lipogenesis, increases body weight, improves gastric motility, reduces catabolic wasting and inflammation. Several randomized, double-blind, placebo-controlled clinical trials evaluating anamorelin, a ghrelin agonist, for the treatment of CACS have reported improvement in appetite and body composition including both lean body and fat mass; however, most studies noted no improvement in physical function as assessed by measuring non-dominant hand-grip strength. Common adverse effects of anamorelin include the development of diabetes mellitus, hyperglycemia, and less frequently, hepatic abnormalities and cardiovascular events including conduction abnormalities, hypertension, and ischemic cardiomyopathy. Anamorelin has the potential to stimulate appetite, improve gastric movement, and may have anti-inflammatory effects on patients with CACS. In patients with cancer, studies involving anamorelin combined with other multimodal treatments including nutrition counseling (branched chain amino acids, omega 3 fatty acids, and other nutrients), exercise, treatment of hormonal abnormalities including hypogonadism and hypovitaminosis D, and anti-inflammatory agents are needed. Compliance with multimodality treatment has been a barrier and future studies may need to incorporate motivational counseling to promote adherence.

The effect of anamorelin (ONO-7643) on cachexia in cancer patients: Systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Cachexia is associated with increased morbidity and mortality rates in patients with cancer. This meta-analysis aims to explore the effect of anamorelin on cancer cachexia markers.

METHODS

We searched MEDLINE/PubMed, SCOPUS, and WOS from their inception until 5 June 2022. A systematic search was conducted according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. We included trials investigating the effect of anamorelin on body weight, lean body mass, fat mass, insulin-like growth factor 1 (IGF-1), handgrip, quality of life insulin-like growth factor-binding protein 3 (IGFBP-3), and in patients with cancer. A random-effects model was run to pooled results.

RESULTS

Five articles providing 1331 participants were analyzed in this study. Pooled analysis revealed a significant increase in body weight (weighted mean difference (WMD): 1.56 kg, 95% confidence interval (CI): 1.20, 1.92; I2= 0%), lean body mass (WMD: 1.36 kg, 95% CI: 0.85, 1.86; I2= 53.1%), fat mass (WMD: 1.02 kg, 95% CI: 0.51, 1.53; I2= 60.7%), IGF-1 (WMD: 51.16 ng/mL, 95% CI: 41.42, 60.90, I2= 0%), and IGFBP-3 (WMD: 0.43 μg/mL, 95% CI: 0.17, 0.68, I2= 98.6%). Results showed no significant increase in appetite when analysis run on all studies without considering different doses 0.29 (95% CI: -0.30, 0.89, I2= 73.8%), however, there was a significant increase in appetite without heterogeneity and inconsistency 0.59 (95% CI: 0.32, 0.86; I2= 0%) in the 100 mg/day group compared to anamorelin non-user.

CONCLUSIONS

Patients with cancer who receive anamorelin as a treatment for cachexia showed a significant increase in body weight, lean body mass, fat mass, IGF-1, and IGFBP-3.

The landscape of cancer cachexia in advanced non-small cell lung cancer: a narrative review

Background and Objective

Cancer cachexia presents with weight loss, anorexia, and fatigue and worsens the prognosis and quality of life of cancer patients. We aimed to summarize the current relevant discourse in the literature about cancer cachexia in the setting of non-small cell lung carcinoma and the possible current and future treatments.

Methods

We conduct a narrative review of the literature on the landscape of cancer cachexia in the context of non-small cell lung cancer, multimodality therapy, markers, imaging, tumor biology, pathology, chemoprevention, and technical advances.

Key Content and Findings

The need for appropriate intervention for cancer cachexia is increasing as the prognosis of patients with advanced non-small cell lung cancer is improving with advances in treatment. Tumor cells play a role in the pathogenesis of cachexia, where they release factors that elicit the production of inflammatory cytokines by the immune system resulting in decreased appetite, abnormal energy metabolism, and skeletal muscle degeneration. Comorbid chronic lung diseases are associated with pulmonary cachexia and sarcopenia and commonly occur in the context of lung cancer, further contributing to the increased incidence of cachexia in patients with lung cancer. Currently, a ghrelin-like agonist, anamorelin, is approved for the treatment of cancer cachexia and is used in clinical practice in Japan. The role that nutritional and exercise therapies can play as added treatments must be further explored.

Conclusions

Cancer cachexia remains a poorly understood phenomenon, and awareness must be raised through educational activities for health care providers and patient family members. In addition, new therapeutics targeting cancer cachexia, such as GDF-15 antibodies, are in development, and further progress is expected.

Blocking ActRIIB and restoring appetite reverses cachexia and improves survival in mice with lung cancer

Cancer cachexia is a common, debilitating condition with limited therapeutic options. Using an established mouse model of lung cancer, we find that cachexia is characterized by reduced food intake, spontaneous activity, and energy expenditure accompanied by muscle metabolic dysfunction and atrophy. We identify Activin A as a purported driver of cachexia and treat with ActRIIB-Fc, a decoy ligand for TGF-β/activin family members, together with anamorelin (Ana), a ghrelin receptor agonist, to reverse muscle dysfunction and anorexia, respectively. Ana effectively increases food intake but only the combination of drugs increases lean mass, restores spontaneous activity, and improves overall survival. These beneficial effects are limited to female mice and are dependent on ovarian function. In agreement, high expression of Activin A in human lung adenocarcinoma correlates with unfavorable prognosis only in female patients, despite similar expression levels in both sexes. This study suggests that multimodal, sex-specific, therapies are needed to reverse cachexia.

Ghrelin and Cancer: Examining the Roles of the Ghrelin Axis in Tumor Growth and Progression

Ghrelin, a hormone produced and secreted from the stomach, is prim arily known as an appetite stimulant. Recently, it has emerged as a potential regulator/biomarker of cancer progression. Inconsistent results on this subject make this body of literature difficult to interpret. Here, we attempt to identify commonalities in the relationships between ghrelin and various cancers, and summarize important considerations for future research. The main players in the ghrelin family axis are unacylated ghrelin (UAG), acylated ghrelin (AG), the enzyme ghrelin O-acyltransferase (GOAT), and the growth hormone secretagogue receptor (GHSR). GOAT is responsible for the acylation of ghrelin, after which ghrelin can bind to the functional ghrelin receptor GHSR-1a to initiate the activation cascade. Splice variants of ghrelin also exist, with the most prominent being In1-ghrelin. In this review, we focus primarily on the potential of In1-ghrelin as a biomarker for cancer progression, the unique characteristics of UAG and AG, the importance of the two known receptor variants GHSR-1a and 1b, as well as the possible mechanisms through which the ghrelin axis acts. Further understanding of the role of the ghrelin axis in tumor cell proliferation could lead to the development of novel therapeutic approaches for various cancers.

Advances in the Development of Nonpeptide Small Molecules Targeting Ghrelin Receptor

Ghrelin is an octanoylated peptide acting by the activation of the growth hormone secretagogue receptor, namely, GHS-R1a. The involvement of ghrelin in several physiological processes, including stimulation of food intake, gastric emptying, body energy balance, glucose homeostasis, reduction of insulin secretion, and lipogenesis validates the considerable interest in GHS-R1a as a promising target for the treatment of numerous disorders. Over the years, several GHS-R1a ligands have been identified and some of them have been extensively studied in clinical trials. The recently resolved structures of GHS-R1a bound to ghrelin or potent ligands have provided useful information for the design of new GHS-R1a drugs. This perspective is focused on the development of recent nonpeptide small molecules acting as GHS-R1a agonists, antagonists, and inverse agonists, bearing classical or new molecular scaffolds, as well as on radiolabeled GHS-R1a ligands developed for imaging. Moreover, the pharmacological effects of the most studied ligands have been discussed.

[Pharmacological profile and clinical efficacy of anamorelin HCl (ADLUMIZ®Tablets), the first orally available drug for cancer cachexia with ghrelin-like action in Japan]

Anamorelin hydrochloride (hereinafter referred to as anamorelin) is an orally active, small-molecule drug with a similar pharmacological action to ghrelin, an endogenous ligand of growth hormone secretagogue receptor type 1a (GHS-R_1a). It was first approved in Japan for the treatment of cancer cachexia, characterized by weight loss and anorexia. Anamorelin stimulated the secretion of growth hormone (GH) from cultured rat pituitary cells and increased plasma GH levels by oral administration to rats, pigs and humans. When anamorelin was orally administered once daily for 6 days to rats, larger body weight gain associated with increased food consumption compared to the control group was observed from after the first dose. Anamorelin is a selective agonist for GHS-R_1a and enhanced GHS-R_1a-mediated pituitary GH secretion and increased food consumption, resulting in body weight gain. In the two Japanese phase II studies in patients with cancer cachexia associated with non-small cell lung cancer (NSCLC), improvement of lean body mass (LBM) and body weight losses and anorexia were demonstrated. The tumor types of target patients in the Japanese phase III study were colorectal, gastric, and pancreatic cancer. As a result, maintenance and increase of LBM and body weight as well as improvement of anorexia were observed, and the efficacy against cancer cachexia associated with colorectal, gastric, and pancreatic cancer was confirmed. There were no observed events considered to be significant safety risks. In conclusion, anamorelin is expected to provide a new therapeutic option for cancer cachexia for which no effective treatment has been available.

Skeletal muscle atrophy: From mechanisms to treatments

Skeletal muscle is a crucial tissue for movement, gestural assistance, metabolic homeostasis, and thermogenesis. It makes up approximately 40% of the total body weight and 50% of total protein. However, several pathological abnormalities (e.g., chronic diseases, cancer, long-term infection, aging) can induce an imbalance in skeletal muscle protein synthesis and degradation, which triggers muscle wasting and even leads to atrophy. Skeletal muscle atrophy is characterized by weakening, shrinking, and decreasing muscle mass and fiber cross-sectional area at the histological level. It manifests as a reduction in force production, easy fatigue and decreased exercise capability, along with a lower quality of life. Mechanistically, there are several pathophysiological processes involved in skeletal muscle atrophy, including oxidative stress and inflammation, which then activate signal transduction, such as the ubiquitin proteasome system, autophagy lysosome system, and mTOR. Considering the great economic and social burden that muscle atrophy can inflict, effective prevention and treatment strategies are essential but still limited. Exercise is widely acknowledged as the most effective therapy for skeletal muscle atrophy; unfortunately, it is not applicable for all patients. Several active substances for skeletal muscle atrophy have been discovered and evaluated in clinical trials, however, they have not been marketed to date. Knowledge is being gained on the underlying mechanisms, highlighting more promising treatment strategies in the future. In this paper, the mechanisms and treatment strategies for skeletal muscle atrophy are briefly reviewed.

G protein-coupled receptors can control the Hippo/YAP pathway through Gq signaling

The Hippo pathway is an evolutionarily conserved kinase cascade involved in the control of tissue homeostasis, cellular differentiation, proliferation, and organ size, and is regulated by cell-cell contact, apical cell polarity, and mechanical signals. Miss-regulation of this pathway can lead to cancer. The Hippo pathway acts through the inhibition of the transcriptional coactivators YAP and TAZ through phosphorylation. Among the various signaling mechanisms controlling the hippo pathway, activation of G12/13 by G protein-coupled receptors (GPCR) recently emerged. Here we show that a GPCR, the ghrelin receptor, that activates several types of G proteins, including G12/13, Gi/o, and Gq, can activate YAP through Gq/11 exclusively, independently of G12/13. We revealed that a strong basal YAP activation results from the high constitutive activity of this receptor, which can be further increased upon agonist activation. Thus, acting on ghrelin receptor allowed to modulate up-and-down YAP activity, as activating the receptor increased YAP activity and blocking constitutive activity reduced YAP activity. Our results demonstrate that GPCRs can be used as molecular switches to finely up- or down-regulate YAP activity through a pure Gq pathway.

Exploration of the role of serum ghrelin in the diagnosis and treatment of digestive tract malignancies

Objective

The incidence of digestive tract malignancies (DTMs) is increasing, early diagnosis is limited, and treatment effects are unsatisfactory. DTMs express ghrelin, which might be involved in tumor formation and development; whether serum ghrelin can provide useful guidance remains unknown.

Methods

Sera of healthy individuals were obtained from October 2017 through March 2018; serum samples from patients with gastric (GC), colon (CC), and rectal (RC) cancers were collected during the same period. Serum ghrelin was tested by ELISA and correlated with clinicopathology of patients with DTMs.

Results

Serum ghrelin was higher in patients (GC, 38 patients; CC, 24; RC, 26) than in 69 healthy individuals and decreased significantly after tumor resection. Nutrition Risk Screening 2002 score and neutrophil:lymphocyte ratio affected perioperative serum ghrelin levels. The epithelial cell marker AE1/AE3 (pan keratin) in patients with GC, tumor location in the colon in patients with CC, and age in patients with RC also affected perioperative serum ghrelin.

Conclusions

Serum ghrelin might provide early warning of occurrence and guide prognosis of DTMs. Ghrelin can be used when screening for nutritional risk and inflammation. The clinicopathological influence on serum ghrelin in patients with DTMs is related to tumor location in the digestive tract.

An overview of anamorelin as a treatment option for cancer-associated anorexia and cachexia

INTRODUCTION

Cancer cachexia is a complex multifaceted syndrome involving functional impairment, changes in body composition, and nutritional disorders. The treatment of cancer cachexia can be based on these three domains of the syndrome. Phase II and III trials of anamorelin, a ghrelin mimetic agent, have been shown to increase body weight in patients with cancer cachexia, mainly by increasing muscle and fat mass. Anamorelin has been shown to improve anorexia scores.

AREAS COVERED

This review aims to outline the effect of anamorelin on body composition and functional parameters as well as to discuss the clinical importance of these alterations in patients with cancer cachexia.

EXPERT OPINION

To date, there is no treatment approved to enhance body composition and functional parameters in patients with cancer cachexia. Anamorelin, the most advanced therapy to treat cachexia, has not yielded convincing results in all aspects of the syndrome. In particular, no effect has been noted on physical function and long-term survival. Along with these essential improvements for future interventions with anamorelin, subsequent studies must address other etiologies of cancer, rather than non-small cell lung cancer, and add complementary therapies, such as exercise training and nutritional interventions, in an attempt to overcome cancer cachexia.

Characterization of cachexia in the human fibrosarcoma HT-1080 mouse tumour model

BACKGROUND

Cancer cachexia is a complex metabolic disease with unmet medical need. Although many rodent models are available, none are identical to the human disease. Therefore, the development of new preclinical models that simulate some of the physiological, biochemical, and clinical characteristics of the human disease is valuable. The HT-1080 human fibrosarcoma tumour cell line was reported to induce cachexia in mice. Therefore, the purpose of this work was to determine how well the HT-1080 tumour model could recapitulate human cachexia and to examine its technical performance. Furthermore, the efficacy of ghrelin receptor activation via anamorelin treatment was evaluated, because it is one of few clinically validated mechanisms.

METHODS

Female severe combined immunodeficient mice were implanted subcutaneously or heterotopically (renal capsule) with HT-1080 tumour cells. The cachectic phenotype was evaluated during tumour development, including body weight, body composition, food intake, muscle function (force and fatigue), grip strength, and physical activity measurements. Heterotopic and subcutaneous tumour histology was also compared. Energy balance was evaluated at standard and thermoneutral housing temperatures in the subcutaneous model. The effect of anamorelin (ghrelin analogue) treatment was also examined.

RESULTS

The HT-1080 tumour model had excellent technical performance and was reproducible across multiple experimental conditions. Heterotopic and subcutaneous tumour cell implantation resulted in similar cachexia phenotypes independent of housing temperature. Tumour weight and histology was comparable between both routes of administration with minimal inflammation. Subcutaneous HT-1080 tumour-bearing mice presented with weight loss (decreased fat mass and skeletal muscle mass/fibre cross-sectional area), reduced food intake, impaired muscle function (reduced force and grip strength), and decreased spontaneous activity and voluntary wheel running. Key circulating inflammatory biomarkers were produced by the tumour, including growth differentiation factor 15, Activin A, interleukin 6, and TNF alpha. Anamorelin prevented but did not reverse anorexia and weight loss in the subcutaneous model.

CONCLUSIONS

The subcutaneous HT-1080 tumour model displays many of the perturbations of energy balance and physical performance described in human cachexia, consistent with the production of key inflammatory factors. Anamorelin was most effective when administered early in disease progression. The HT-1080 tumour model is valuable for studying potential therapeutic targets for the treatment of cachexia.

Supplementary Oral Anamorelin Mitigates Anorexia and Skeletal Muscle Atrophy Induced by Gemcitabine Plus Cisplatin Systemic Chemotherapy in a Mouse Model

Chemotherapy-induced adverse effects can reduce the relative dose intensity and quality of life. In this study, we investigated the potential benefit of supplementary anamorelin and 5-aminolevulinic acid (5-ALA) as preventive interventions against a gemcitabine and cisplatin (GC) combination chemotherapy-induced adverse effects in a mouse model. Non-cancer-bearing C3H mice were randomly allocated as follows and treated for 2 weeks—(1) non-treated control, (2) oral anamorelin alone, (3) oral 5-ALA alone, (4) gemcitabine and cisplatin (GC) chemotherapy, (5) GC plus anamorelin, and (6) GC plus 5-ALA. GC chemotherapy significantly decreased body weight, food intake, skeletal muscle mass and induced severe gastric mucositis, which resulted in decreased ghrelin production and blood ghrelin level. The supplementation of oral anamorelin to GC chemotherapy successfully mitigated decrease of food intake during the treatment period and body weight loss at day 8. In addition, analysis of the resected muscles and stomach revealed that anamorelin suppressed chemotherapy-induced skeletal muscle atrophy by mediating the downregulation of forkhead box protein O-1 (FOXO1)/atrogin-1 signaling and gastric damage. Our findings suggest the preventive effect of anamorelin against GC combination chemotherapy, which was selected for patients with some types of advanced malignancies in clinical practice.

A multicenter, open-label, single-arm study of anamorelin (ONO-7643) in advanced gastrointestinal cancer patients with cancer cachexia

Background

Cancer cachexia is characterized by weight loss and is associated with increased morbidity and mortality in patients with cancer. Anamorelin (ONO‐7643; ANAM) is a novel and selective ghrelin receptor agonist that improves appetite, lean body mass (LBM), body weight, and anorexia.

Methods

This multicenter, open‐label, single‐arm study investigated the efficacy and safety of 100 mg anamorelin in 50 Japanese patients with advanced and unresectable gastrointestinal (colorectal, gastric, or pancreatic) cancer. ANAM was administered once daily over 12 weeks. The primary endpoint was the proportion of patients that maintained or gained LBM over the course of the study. Secondary endpoints included changes in LBM, body weight, quality of life (QoL), and nutritional status biomarkers.

Results

The proportion of patients who responded to treatment was 63.3% (95% CI, 48.3%‐76.6%), with a least square mean ± SE change in LBM and body weight from baseline of 1.89 ± 0.36 kg and 1.41 ± 0.61 kg, respectively. Appetite‐related questions on the QoL questionnaire showed that ANAM improved appetite. Adverse events occurred in 79.6% of patients, and the most common treatment‐related adverse events were increased γ‐glutamyl transpeptidase (8.2%), diabetes mellitus (6.1%), hyperglycemia (6.1%), and prolonged QRS complex (6.1%).

Conclusions

ANAM improved anorexia and patients' nutritional status, resulting in rapid increases in LBM and body weight in patients with advanced gastrointestinal cancer who had cancer cachexia. ANAM treatment was well tolerated over 12 weeks. ANAM is a potential clinically beneficial pharmacotherapeutic option for patients with advanced gastrointestinal cancer who have cancer cachexia.

The receipt of 100 mg anamorelin increases lean body mass and improves symptoms of anorexia and nutritional status in patients with advanced gastrointestinal cancer who have cancer cachexia. Anamorelin is well tolerated in these patients.

Leukemia inhibitory factor via the Toll-like receptor 5 signaling pathway involves aggravation of cachexia induced by human gastric cancer-derived 85As2 cells in rats

Cancer cachexia is highly prevalent in gastric cancer patients and characterized by decreased food consumption and body weight. We previously created a rat model of cancer cachexia using MKN45cl85 and 85As2 cells derived from human gastric cancer. The 85As2 cells induced cachexia more potently compared to MKN45cl85 cells. To clarify the mechanism underlying the difference in the cachexia-inducing ability of these cells, we conducted DNA microarray analysis, focusing on cell proliferation and the production of leukemia inhibitory factor (LIF), a cachexia-inducing factor. The plasma human LIF levels of 85As2-induced cachexic rats increased as symptoms worsened, whereas the plasma levels of MKNcl85 were low. 85As2 cells displayed more genetic changes compared to MKN45cl85 cells, which were related to Toll-like receptor (TLR) 4/5 signaling. Stimulation of both cells with TLR4 (lipopolysaccharide) or TLR5 (flagellin) agonists did not affect proliferation. However, in 82As2 cells, LIF production was significantly increased by stimulation with TLR5, which was suppressed by an inhibitor of interleukin-1 receptor-associated kinase-1/4, which are important factors in the TLR5 signaling pathway. The increase in LIF production resulting from activation of the TLR5 signaling pathway may contribute to the cachexia-inducing ability of 85As2 cells.

Ghrelin agonist HM01 attenuates chemotherapy-induced neurotoxicity in rodent models

Chemotherapy-Induced Peripheral Neurotoxicity (CIPN) is often dose-limiting and impacts life quality and survival of cancer patients. Ghrelin agonists have neuroprotectant effects and may have a role in treating or preventing CIPN. We evaluated the CNS-penetrant ghrelin agonist HM01 in three experimental models of CIPN at doses of 3-30 mg/kg p.o. daily monitoring orexigenic properties, nerve conduction, mechanical allodynia, and intra-epidermal nerve fiber density (IENFD). In a cisplatin-based study, rats were dosed daily for 3 days (0.5 mg/kg i.p.) + HM01. Cisplatin treatment induced mechanical hypersensitivity which was significantly reduced by HM01. In a second study, oxaliplatin was administered to mice (6 mg/kg i.p. 3 times/week for 4 weeks) resulting in significant digital nerve conduction velocity (NCV) deficits and reduction of IENFD. Concurrent HM01 dose dependently prevented the decline in NCV and attenuated the reduction in IENFD. Pharmacokinetic studies showed HM01 accumulation in the dorsal root ganglia and sciatic nerves which reached concentrations > 10 fold that of plasma. In a third model, HM01 was tested in preventive and therapeutic paradigms in a bortezomib-based rat model (0.2 mg/kg i.v., 3 times/week for 8 weeks). In the preventive setting, HM01 blocked bortezomib-induced hyperalgesia and IENFD reduction at all doses tested. In the therapeutic setting, significant effect was observed, but only at the highest dose. Altogether, the robust peripheral nervous system penetration of HM01 and its ability to improve multiple oxaliplatin-, cisplatin-, and bortezomib-induced neurotoxicities suggest that HM01 may be a useful neuroprotective adjuvant for CIPN.

Ghrelin for the management of cachexia associated with cancer

BACKGROUND

Cancer sufferers are amongst the most malnourished of all the patient groups. Studies have shown that ghrelin, a gut hormone can be a potential therapeutic agent for cachexia (wasting syndrome) associated with cancer. A variety of mechanisms of action of ghrelin in people with cancer cachexia have been proposed. However, safety and efficacy of ghrelin for cancer-associated cachexia have not been systematically reviewed. The aim of this review was to assess whether ghrelin is associated with better food intake, body composition and survival than other options for adults with cancer cachexia.

OBJECTIVES

To assess the efficacy and safety of ghrelin in improving food intake, body composition and survival in people with cachexia associated with cancer.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase without language restrictions up to July 2017. We also searched for ongoing studies in trials registers, performed handsearching, checked bibliographic references of relevant articles and contacted authors and experts in the field to seek potentially relevant research. We applied no restrictions on language, date, or publication status.

SELECTION CRITERIA

We included randomised controlled (parallel-group or cross-over) trials comparing ghrelin (any formulation or route of administration) with placebo or an active comparator in adults (aged 18 years and over) who met any of the international criteria for cancer cachexia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility. Two review authors then extracted data and assessed the risk of bias for individual studies using standard Cochrane methodology. For dichotomous variables, we planned to calculate risk ratio with 95% confidence intervals (CI) and for continuous data, we planned to calculate mean differences (MD) with 95% CI. We assessed the evidence using GRADE and created 'Summary of findings' tables.

MAIN RESULTS

We screened 926 individual references and identified three studies that satisfied the inclusion criteria. Fifty-nine participants (37 men and 22 women) aged between 54 and 78 years were randomised initially, 47 participants completed the treatment. One study had a parallel design and two had a cross-over design. The studies included people with a variety of cancers and also differed in the dosage, route of administration, frequency and duration of treatment.One trial, which compared ghrelin with placebo, found that ghrelin improved food intake (very low-quality evidence) and had no adverse events (very low-quality evidence). Due to unavailability of data we were unable to report on comparisons for ghrelin versus no treatment or alternative experimental treatment modalities, or ghrelin in combination with other treatments or ghrelin analogues/ghrelin mimetics/ghrelin potentiators. Two studies compared a higher dose of ghrelin with a lower dose of ghrelin, however due to differences in study designs and great diversity in the treatment provided we did not pool the results. In both trials, food intake did not differ between participants on higher-dose and lower-dose ghrelin. None of the included studies assessed data on body weight. One study reported higher adverse events with a higher dose as compared to a lower dose of ghrelin.All studies were at high risk of attrition bias and bias for size of the study. Risk of bias in other domains was unclear or low.We rated the overall quality of the evidence for primary outcomes (food intake, body weight, adverse events) as very low. We downgraded the quality of the evidence due to lack of data, high or unclear risk of bias of the studies and small study size.

AUTHORS' CONCLUSIONS

There is insufficient evidence to be able to support or refute the use of ghrelin in people with cancer cachexia. Adequately powered randomised controlled trials focusing on evaluation of safety and efficacy of ghrelin in people with cancer cachexia is warranted.

Oncology Update: Anamorelin

Background:

Cancer cachexia is a catabolic syndrome associated with uncontrolled muscle breakdown. There may be associated fat loss. Occurring in high frequency in advanced cancer, it is an indicator of poor prognosis. Besides weight loss, patients experience a cluster of symptoms including anorexia, early satiety, and weakness. The 3 stages of cachexia include stages of precachexia, cachexia, and refractory cachexia. Refractory cachexia is associated with active catabolism or the presence of factors that make active management of weight loss no longer possible. Patients with refractory cachexia often receive glucocorticoids or megasterol acetate. Glucocorticoid effect is short and responses to megasterol are variable. Anamorelin is a new agent for cancer anorexia-cachexia, with trials completed in advanced lung cancer. Acting as an oral mimetic of ghrelin, it improves appetite and muscle mass. This article reviews the pharmacology, pharmacodynamics, and effect on cancer cachexia.

Methods:

A PubMed search was done using the Medical Subject Headings term anamorelin. Articles were selected to provide a pharmacologic characterization of anamorelin.

Results:

Anamorelin increases muscle mass in patients with advanced cancer in 2-phase 3 trials.

Conclusions:

Anamorelin improves anorexia-cachexia symptoms in patients with advanced non–small-cell lung cancer.

Anamorelin hydrochloride in the treatment of cancer anorexia-cachexia syndrome: design, development, and potential place in therapy

Cancer anorexia–cachexia syndrome (CACS) is a complex and largely untreatable paraneoplastic complication common in advanced cancer. It is associated with profoundly deleterious effects on quality of life and survival. Since its discovery over a decade ago, anamorelin hydrochloride (anamorelin), a mimetic of the growth hormone secretagogue ghrelin, has shown considerable promise in ameliorating components of CACS when administered to patients with advanced cancer, including loss of lean body mass and reversal of anorexia. This review summarizes the development of anamorelin and its safety and efficacy in clinical investigations. The potential future role of anamorelin in treating CACS is also discussed.

The emerging role of anamorelin hydrochloride in the management of patients with cancer anorexia-cachexia

Cancer cachexia affects many patients with advanced cancer. This multifactorial syndrome, which involves loss of muscle mass and body weight, profoundly affects patients' physical functioning and quality of life. Pharmacologic interventions that target weight loss and also improve patient-reported measures are required. Anamorelin hydrochloride is an oral ghrelin receptor agonist for the treatment of cancer anorexia-cachexia that stimulates release of growth hormone and insulin-like growth factor 1, and improves food intake and body weight. Phase II and III trials have demonstrated that anamorelin increases body muscle and fat composition, and improves patient-reported appetite and quality of life. Anamorelin shows promise as an anabolic agent with benefits maintained over time, without the virilizing side effects of other anabolic medications.

Oral Treatment with the Ghrelin Receptor Agonist HM01 Attenuates Cachexia in Mice Bearing Colon-26 (C26) Tumors

The gastrointestinal hormone ghrelin reduces energy expenditure and stimulates food intake. Ghrelin analogs are a possible treatment against cancer anorexia-cachexia syndrome (CACS). This study aimed to investigate whether oral treatment with the non-peptidergic ghrelin receptor agonist HM01 counteracts CACS in colon-26 (C26) tumor-bearing mice. The C26 tumor model is characterized by pronounced body weight (BW) loss and muscle wasting in the absence of severe anorexia. We analyzed the time course of BW loss, body composition, muscle mass, bone mineral density, and the cytokines interleukin-6 (IL-6) and macrophage-inhibitory cytokine-1 (MIC-1). Moreover, we measured the expression of the muscle degradation markers muscle RING-finger-protein-1 (MuRF-1) and muscle atrophy F-box (MAFbx). After tumor inoculation, MIC-1 levels increased earlier than IL-6 and both cytokines were elevated before MuRF-1/MAFbx expression increased. Oral HM01 treatment increased BW, fat mass, and neuronal hypothalamic activity in healthy mice. In tumor-bearing mice, HM01 increased food intake, BW, fat mass, muscle mass, and bone mineral density while it decreased energy expenditure. These effects appeared to be independent of IL-6, MIC-1, MuRF-1 or MAFbx, which were not affected by HM01. Therefore, HM01 counteracts cachectic body weight loss under inflammatory conditions and is a promising compound for the treatment of cancer cachexia in the absence of severe anorexia.

Therapeutic Potential of Targeting the Ghrelin Pathway

Ghrelin was discovered in 1999 as the endogenous ligand of the growth-hormone secretagogue receptor 1a (GHSR1a). Since then, ghrelin has been found to exert a plethora of physiological effects that go far beyond its initial characterization as a growth hormone (GH) secretagogue. Among the numerous well-established effects of ghrelin are the stimulation of appetite and lipid accumulation, the modulation of immunity and inflammation, the stimulation of gastric motility, the improvement of cardiac performance, the modulation of stress, anxiety, taste sensation and reward-seeking behavior, as well as the regulation of glucose metabolism and thermogenesis. Due to a variety of beneficial effects on systems’ metabolism, pharmacological targeting of the endogenous ghrelin system is widely considered a valuable approach to treat metabolic complications, such as chronic inflammation, gastroparesis or cancer-associated anorexia and cachexia. The aim of this review is to discuss and highlight the broad pharmacological potential of ghrelin pathway modulation for the treatment of anorexia, cachexia, sarcopenia, cardiopathy, neurodegenerative disorders, renal and pulmonary disease, gastrointestinal (GI) disorders, inflammatory disorders and metabolic syndrome.

Anamorelin for cancer anorexia-cachexia syndrome: a systematic review and meta-analysis

PURPOSE

The aim of this study was to evaluate the therapeutic effects of Anamorelin on patients with cancer anorexia-cachexia syndrome (CACS) based on a meta-analysis of published randomized trials.

METHODS

We searched PubMed, Embase, Medline, and the Cochrane Central Register of Controlled Trials databases. Data from each selected study were evaluated individually. All continuous outcomes were calculated by the mean difference or standardized mean difference with 95% confidence interval for each study. Heterogeneity was assessed by using the Chi² test at a significance level of P < 0.1, in addition to the I ² statistic (I ² > 50% indicated substantial heterogeneity).

RESULT

At last, four studies were included from 284 records. In three studies, lean body mass was reported and there was a significant difference between placebo and Anamorelin groups (P < 0.00001), without significant heterogeneity (I ² = 0%). All the four studies reported the body weight change from baseline, and there was significant difference between placebo and Anamorelin groups (P = 0.007), but with high heterogeneity (I ² = 97%). Two studies reported Anderson Symptom Assessment Scale (ASAS) score, and Anamorelin significantly increased the total ASAS score of CACS patients (P < 0.00001), without any heterogeneity (I ² = 0%). Three studies reported non-dominant handgrip strength, and there was no significant difference between Anamorelin and placebo groups (P = 0.16). Three studies reported insulin-like growth factor-1 level, and there was significant difference between Anamorelin and placebo groups (P = 0.02), but with high heterogeneity (I ² = 96%). Three studies reported IGF binding protein-3 concentration. Anamorelin significantly increased such concentration compared with placebo did (P < 0.00001). However, there was still higher heterogeneity (I ² = 59%). All the included studies reported adverse events. Compared with placebo, Anamorelin induced fewer adverse events, but there was no significant difference between the two groups (RR = 0.07, P = 0.35).

CONCLUSION

In the included studies, Anamorelin had some positive effects to relieve the symptoms and improved the quality of life. However, the heterogeneity was apparent, so the clinical effects of Anamorelin should be further validated by increasing the sample size, varying the range of doses during treatment, and observing other outcomes. We are still confident for the future application of Anamorelin in phase III clinical trials.

Two ghrelin receptor agonists for adults with malnutrition: a systematic review and meta-analysis

Background

Ghrelin receptor agonists have been established to be important in ameliorating the nutritional conditions in patients with malnutrition. However, some studies have reported inconsistent results. We aimed to coalesce the available evidence on the efficacy of ghrelin receptor agonists for the treatment of malnutrition.

Methods

We searched PubMed, the Cochrane Central Register of Controlled Trials, and EMBASE for relevant articles published through March 2016. Studies comparing the efficacy of ghrelin receptor agonists versus placebo in malnourished patients were eligible for inclusion.

Results

A total of 12 studies involving 1377 patients were included. Compared with placebo, ghrelin receptor agonists could increase the energy intake (standard mean difference [SMD] 2.67, 95% confidence interval [CI] 1.48 to 3.85, P < 0.001), lean body mass (weighted mean difference [WMD] 0.25 kg, 95% CI 0.07 to 0.42, P = 0.006), fat mass (WMD 0.92 kg, 95% CI 0.05 to 1.8, P = 0.038), and grip strength (WMD 0.31 kg, 95% CI 0.207 to 0.414, P < 0.001) of patients with malnutrition.

Conclusion

Our analysis indicated that ghrelin receptor agonists could improve the poor nutritional state of malnourished patients by increasing their energy intake, ameliorating their irregular body composition and improving their grip strength. However, these results might be less conclusive due to the limited sample sizes and one potential publication that has not been released.

A Novel Non-Peptidic Agonist of the Ghrelin Receptor with Orexigenic Activity In vivo

Loss of appetite in the medically ill and ageing populations is a major health problem and a significant symptom in cachexia syndromes, which is the loss of muscle and fat mass. Ghrelin is a gut-derived hormone which can stimulate appetite. Herein we describe a novel, simple, non-peptidic, 2-pyridone which acts as a selective agonist for the ghrelin receptor (GHS-R1a). The small 2-pyridone demonstrated clear agonistic activity in both transfected human cells and mouse hypothalamic cells with endogenous GHS-R1a receptor expression. In vivo tests with the hit compound showed significant increased food intake following peripheral administration, which highlights the potent orexigenic effect of this novel GHS-R1a receptor ligand.

Is there an effect of ghrelin/ghrelin analogs on cancer? A systematic review

Ghrelin is a hormone with multiple physiologic functions, including promotion of growth hormone release, stimulation of appetite and regulation of energy homeostasis. Treatment with ghrelin/ghrelin-receptor agonists is a prospective therapy for disease-related cachexia and malnutrition. In vitro studies have shown high expression of ghrelin in cancer tissue, although its role including its impact in cancer risk and progression has not been established. We performed a systematic literature review to identify peer-reviewed human or animal in vivo original research studies of ghrelin, ghrelin-receptor agonists, or ghrelin genetic variants and the risk, presence, or growth of cancer using structured searches in PubMed database as well as secondary searches of article reference lists, additional reviews and meta-analyses. Overall, 45 (73.8%) of the 61 studies reviewed, including all 11 involving exogenous ghrelin/ghrelin-receptor agonist treatment, reported either a null (no statistically significant difference) or inverse association of ghrelin/ghrelin-receptor agonists or ghrelin genetic variants with cancer risk, presence or growth; 10 (16.7%) studies reported positive associations; and 6 (10.0%) reported both negative or null and positive associations. Differences in serum ghrelin levels in cancer cases vs controls (typically lower) were reported for some but not all cancers. The majority of in vivo studies showed a null or inverse association of ghrelin with risk and progression of most cancers, suggesting that ghrelin/ghrelin-receptor agonist treatment may have a favorable safety profile to use for cancer cachexia. Additional large-scale prospective clinical trials as well as basic bioscientific research are warranted to further evaluate the safety and benefits of ghrelin treatment in patients with cancer.

Lentivirus-mediated shRNA interference of ghrelin receptor blocks proliferation in the colorectal cancer cells

Ghrelin, an orexigenic peptide, acts via the growth hormone secretagogue receptor (GHSR) to stimulate the release of growth hormone. Moreover, it has a range of biological actions, including the stimulation of food intake, modulation of insulin signaling and cardiovascular effects. Recently, it has been demonstrated that ghrelin has a proliferative and antiapoptotic effects in cancers, suggesting a potential role in promoting tumor growth. However, it remains unknown whether GHSR contributes to colorectal cancer proliferation. In this study, the therapeutic effect of lentivirus‐mediated short hairpin RNA (shRNA) targeting ghrelin receptor 1a (GHSR1a) was analyzed in colorectal cancer cell line SW480 both in vitro and in vivo. Our study demonstrated that ghrelin and GHSR1a are significantly upregulated in cancerous colorectal tissue samples and cell lines. In vitro, human colorectal cancer cell line SW480 with downregulation of GHSR1a by shRNA showed significant inhibition of cell viability compared with blank control (BC) or scrambled control (SC) regardless of the application of exogenous ghrelin. Furthermore, GHSR1a silencing by target specific shRNA was shown capable of increasing PTEN, inhibiting AKT phosphorylation and promoting the release of p53 in SW480 cells. In addition, the effects of GHSR1a knockdown were further explored in vivo using colorectal tumor xenograft mouse model. The tumor weights were decreased markedly in GHSR1α knockdown SW480 mouse xenograft tumors compared with blank control or negative control tumors. Our results suggested that the expression of GHSR1a is significantly correlated with the growth of colorectal cancer cells, and the GHSR1a knockdown approach may be a potential therapy for the treatment of colorectal cancer.

The ghrelin receptor agonist HM01 mimics the neuronal effects of ghrelin in the arcuate nucleus and attenuates anorexia-cachexia syndrome in tumor-bearing rats

The gastric hormone ghrelin positively affects energy balance by increasing food intake and reducing energy expenditure. Ghrelin mimetics are a possible treatment against cancer anorexia-cachexia syndrome (CACS). This study aimed to characterize the action of the nonpeptidergic ghrelin receptor agonist HM01 on neuronal function, energy homeostasis and muscle mass in healthy rats and to evaluate its possible usefulness for the treatment of CACS in a rat tumor model. Using extracellular single-unit recordings, we tested whether HM01 mimics the effects of ghrelin on neuronal activity in the arcuate nucleus (Arc). Furthermore, we assessed the effect of chronic HM01 treatment on food intake (FI), body weight (BW), lean and fat volumes, and muscle mass in healthy rats. Using a hepatoma model, we investigated the possible beneficial effects of HM01 on tumor-induced anorexia, BW loss, muscle wasting, and metabolic rate. HM01 (10(-7)-10(-6) M) mimicked the effect of ghrelin (10(-8) M) by increasing the firing rate in 76% of Arc neurons. HM01 delivered chronically for 12 days via osmotic minipumps (50 μg/h) increased FI in healthy rats by 24%, paralleled by increased BW, higher fat and lean volumes, and higher muscle mass. Tumor-bearing rats treated with HM01 had 30% higher FI than tumor-bearing controls and were protected against BW loss. HM01 treatment resulted in higher muscle mass and fat mass. Moreover, tumor-bearing rats reduced their metabolic rate following HM01 treatment. Our studies substantiate the possible therapeutic usefulness of ghrelin receptor agonists like HM01 for the treatment of CACS and possibly other forms of disease-related anorexia and cachexia.

Anamorelin (ONO-7643) in Japanese patients with non-small cell lung cancer and cachexia: results of a randomized phase 2 trial

Purpose

Cancer cachexia is characterized by decreased body weight (mainly lean body mass [LBM]) and negatively impacts quality of life (QOL) and prognosis. Anamorelin (ONO-7643) is a novel selective ghrelin receptor agonist under development for treating cancer cachexia.

Methods

In this double-blind, exploratory phase 2 trial, we examined the efficacy and safety of anamorelin in Japanese patients (n = 181) with non-small cell lung cancer (NSCLC) and cancer cachexia (≥5 % weight loss within the previous 6 months). The participants were randomized into three groups and were administered 50 or 100 mg anamorelin, or placebo, orally every day for 12 weeks. The co-primary endpoints were the changes from baseline over 12 weeks in LBM and handgrip strength (HGS). Secondary endpoints included body weight, QOL, Karnofsky Performance Scale (KPS), and serum biomarkers.

Results

The change in LBM over 12 weeks was 0.55 and 1.15 kg in the placebo and 100-mg anamorelin groups, respectively, but the efficacy of anamorelin in HGS was not detected. The changes in body weight were −0.93, 0.54, and 1.77 kg in the placebo, 50-mg anamorelin, and 100-mg anamorelin groups, respectively. Anamorelin (100 mg) significantly improved KPS and QOL-ACD compared with placebo. Administration of anamorelin for 12 weeks was well tolerated.

Conclusions

This phase 2 study showed that 100 mg anamorelin has promising results in improving lean body mass, performance status, and especially, QOL in patients with cancer cachexia.

Electronic supplementary material

The online version of this article (doi:10.1007/s00520-016-3144-z) contains supplementary material, which is available to authorized users.

Anamorelin in patients with non-small-cell lung cancer and cachexia (ROMANA 1 and ROMANA 2): results from two randomised, double-blind, phase 3 trials

BACKGROUND

Patients with advanced cancer frequently experience anorexia and cachexia, which are associated with reduced food intake, altered body composition, and decreased functionality. We assessed anamorelin, a novel ghrelin-receptor agonist, on cachexia in patients with advanced non-small-cell lung cancer and cachexia.

METHODS

ROMANA 1 and ROMANA 2 were randomised, double-blind, placebo-controlled phase 3 trials done at 93 sites in 19 countries. Patients with inoperable stage III or IV non-small-cell lung cancer and cachexia (defined as ≥5% weight loss within 6 months or body-mass index <20 kg/m(2)) were randomly assigned 2:1 to anamorelin 100 mg orally once daily or placebo, with a computer-generated randomisation algorithm stratified by geographical region, cancer treatment status, and weight loss over the previous 6 months. Co-primary efficacy endpoints were the median change in lean body mass and handgrip strength over 12 weeks and were measured in all study participants (intention-to-treat population). Both trials are now completed and are registered with ClinicalTrials.gov, numbers NCT01387269 and NCT01387282.

FINDINGS

From July 8, 2011, to Jan 28, 2014, 484 patients were enrolled in ROMANA 1 (323 to anamorelin, 161 to placebo), and from July 14, 2011, to Oct 31, 2013, 495 patients were enrolled in ROMANA 2 (330 to anamorelin, 165 to placebo). Over 12 weeks, lean body mass increased in patients assigned to anamorelin compared with those assigned to placebo in ROMANA 1 (median increase 0·99 kg [95% CI 0·61 to 1·36] vs -0·47 kg [-1·00 to 0·21], p<0·0001) and ROMANA 2 (0·65 kg [0·38 to 0·91] vs -0·98 kg [-1·49 to -0·41], p<0·0001). We noted no difference in handgrip strength in ROMANA 1 (-1·10 kg [-1·69 to -0·40] vs -1·58 kg [-2·99 to -1·14], p=0·15) or ROMANA 2 (-1·49 kg [-2·06 to -0·58] vs -0·95 kg [-1·56 to 0·04], p=0·65). There were no differences in grade 3-4 treatment-related adverse events between study groups; the most common grade 3-4 adverse event was hyperglycaemia, occurring in one (<1%) of 320 patients given anamorelin in ROMANA 1 and in four (1%) of 330 patients given anamorelin in ROMANA 2.

INTERPRETATION

Anamorelin significantly increased lean body mass, but not handgrip, strength in patients with advanced non-small-cell lung cancer. Considering the unmet medical need for safe and effective treatments for cachexia, anamorelin might be a treatment option for patients with cancer anorexia and cachexia.

FUNDING

Helsinn Therapeutics.

Ghrelin attenuates the growth of HO-8910 ovarian cancer cells through the ERK pathway

Ovarian cancer is one of the most common causes of death from gynecologic tumors and is an important public health issue. Ghrelin is a recently discovered bioactive peptide that acts as a natural endogenous ligand of the growth hormone secretagogue receptor (GHSR). Several studies have identified the protective effects of ghrelin on the mammalian reproductive system. However, little research has been done on the effects of ghrelin on ovarian cancer cells, and the underlying mechanisms of these effects. We sought to understand the potential involvement of mitogen-activated protein kinases (MAPKs) in ghrelin-mediated inhibition of growth of the ovarian line HO-8910. We applied different concentrations of ghrelin and an inhibitor of the ghrelin receptor (D-Lys3-GHRP-6) to HO-8910 cells and observed the growth rate of cells and changes in phosphorylation of the MAPKs ERK1/2, JNK and p38. We discovered that ghrelin-induced apoptosis of HO-8910 cells was though phosphorylated ERK1/2, and that this phosphorylation (as well as p90rsk phosphorylation) was mediated by the GHSR. The ERK1/2 pathway is known to play an essential part in the ghrelin-mediated apoptosis of HO-8910 cells. Hence, our study suggests that ghrelin inhibits the growth of HO-8910 cells primarily through the GHSR/ERK pathway.

Cancer as a Proinflammatory Environment: Metastasis and Cachexia

The development of the syndrome of cancer cachexia and that of metastasis are related with a poor prognostic for cancer patients. They are considered multifactorial processes associated with a proinflammatory environment, to which tumour microenvironment and other tissues from the tumour bearing individuals contribute. The aim of the present review is to address the role of ghrelin, myostatin, leptin, HIF, IL-6, TNF-α, and ANGPTL-4 in the regulation of energy balance, tumour development, and tumoural cell invasion. Hypoxia induced factor plays a prominent role in tumour macro- and microenvironment, by modulating the release of proinflammatory cytokines.

A hypothesis for a possible synergy between ghrelin and exercise in patients with cachexia: Biochemical and physiological bases

This article reviews the biochemical and physiological observations underpinning the synergism between ghrelin and ghrelin agonists with exercise, especially progressive resistance training that has been shown to increase muscle mass. The synergy of ghrelin agonists and physical exercise could be beneficial in conditions where muscle wasting is present, such as that found in patients with advanced cancer. The principal mechanism that controls muscle anabolism following the activation of the ghrelin receptor in the central nervous system involves the release of growth hormone/insulin-like growth factor-1 (GH/IGF-1). GH/IGF-1 axis has a dual pathway of action on muscle growth: (a) a direct action on muscle, bone and fat tissue and (b) an indirect action via the production of both muscle-restricted mIGF-1 and anti-cachectic cytokines. Progressive resistance training is a potent inducer of the secretion the muscle-restricted IGF-1 (mIGF-1) that enhances protein synthesis, increases lean body mass and eventually leads to the improvement of muscle strength. Thus, the combination of ghrelin administration with progressive resistance training may serve to circumvent ghrelin resistance and further reduce muscle wasting, which are commonly associated with cachexia.

Mechanisms of anorexia-cachexia syndrome and rational for treatment with selective ghrelin receptor agonist

Cancer cachexia is a multi-organ, multifactorial and often irreversible syndrome affecting many patients with cancer. Cancer cachexia is invariably associated with weight loss, mainly from loss of skeletal muscle and body fat, conditioning a reduced quality of life due to asthenia, anorexia, anaemia and fatigue. Treatment options for treating cancer cachexia are limited. The approach is multimodal and may include: treatment of secondary gastrointestinal symptoms, nutritional treatments, drug, and non-drug treatments. Nutritional counselling and physical training may be beneficial in delaying or preventing the development of anorexia-cachexia. However, these interventions are limited in their effect, and no definitive pharmacological treatment is available to address the relevant components of the syndrome. Anamorelin is a first-in-class, orally active ghrelin receptor agonist that binds and stimulates the growth hormone secretagogue receptor centrally, thereby mimicking the appetite-enhancing and anabolic effects of ghrelin. It represents a new class of drug and an additional treatment option for this patient group, whose therapeutic options are currently limited. In this review we examine the mechanisms of anamorelin by which it contrasts catabolic states, its role in regulation of metabolism and energy homeostasis, the data of recent trials in the setting of cancer cachexia and its safety profile.

Anamorelin hydrochloride for the treatment of cancer-anorexia-cachexia in NSCLC

INTRODUCTION

Cancer anorexia-cachexia syndrome (CACS) is associated with increased morbidity and mortality. Anamorelin is a novel, orally active ghrelin receptor agonist in clinical development for the treatment of CACS in NSCLC. The aim of this review is to summarize preclinical and clinical studies evaluating anamorelin as a potential promising treatment for CACS in NSCLC.

AREAS COVERED

Pharmacodynamics, pharmacokinetics and metabolism, clinical efficacy, safety and tolerability of anamorelin for the treatment of CACS in NSCLC were reviewed. Anamorelin administration may lead to increases in food intake, body weight and lean body mass, and a stimulatory effect on growth hormone secretion in NSCLC patients. Anamorelin is well tolerated with no dose-limiting toxicities identified to date.

EXPERT OPINION

Targeting ghrelin receptors presents the advantage of potentially addressing multiple mechanisms of CACS simultaneously including appetite, muscle protein balance, adipose tissue metabolism, energy expenditure and inflammation. Clinical data suggest that anamorelin is well tolerated and it effectively increases appetite, body weight and lean mass in patients with advanced NSCLC. Long-term safety remains unknown at this time. The potential synergistic effects of anamorelin with nutritional support or exercise as well as its efficacy/safety in other tumor types are also unknown.

Anamorelin for patients with cancer cachexia: an integrated analysis of two phase 2, randomised, placebo-controlled, double-blind trials

BACKGROUND

Cancer anorexia-cachexia syndrome is associated with increased morbidity and mortality. Anamorelin is an oral ghrelin-receptor agonist with appetite-enhancing and anabolic activity. We assessed the effects of anamorelin on body composition, strength, quality of life, biochemical markers, and safety in patients with cancer anorexia-cachexia.

METHODS

Data were pooled, a priori, from two completed phase 2, multicentre, placebo-controlled, double-blind trials in patients with advanced or incurable cancer and weight loss of 5% or more. Patients were stratified by weight loss severity (5-15%, >15%) and randomly allocated (1:1) with a computer-generated randomisation schedule to anamorelin hydrochloride 50 mg or placebo once-daily for 12 weeks. Primary outcome was lean body mass by dual-energy x-ray absorptiometry over the 12 week treatment period in eligible patients who had at least one dose of study drug and post-treatment efficacy assessment. We assessed safety in all patients who received at least one dose of study drug. The trials are registered with ClinicalTrials.gov, numbers NCT00219817 and NCT00267358.

FINDINGS

Between June 29, 2005, and Oct 26, 2006, we enrolled 44 patients in the anamorelin group and 38 patients in the placebo group. 74 patients were eligible for the efficacy analyses. Over 12 weeks, lean body mass increased in 38 patients in the anamorelin group by a least-squares mean of 1.89 kg (95% CI 0.84 to 2.95) compared with a decrease of a least-squares mean of -0.20 kg (-1.23 to 0.83) for 36 patients in the placebo group (difference 2.09 kg [0.94-3.25]; p=0.0006). 42 (95%) of 44 patients treated with anamorelin and 33 (87%) of 38 patients treated with placebo had adverse events. The most common grade 3-4 adverse events (treatment-related or not) in the anamorelin group were fatigue, asthenia, atrial fibrillation, and dyspnoea (two [5%] each); in the placebo group, such events were pneumonia (three [8%]) and anaemia, thrombocytopenia, abdominal pain, anxiety, and dyspnoea (two [5%] each).

INTERPRETATION

Anamorelin treatment for 12 weeks had a favourable clinical response profile in patients with cancer anorexia-cachexia syndrome. These findings support further investigation in this setting.

FUNDING

Helsinn Therapeutics (US), Helsinn Healthcare SA.

Anamorelin HCl (ONO-7643), a novel ghrelin receptor agonist, for the treatment of cancer anorexia-cachexia syndrome: preclinical profile

BACKGROUND

Anamorelin HCl (ANAM) is a novel, orally active, ghrelin receptor agonist in clinical development for the treatment of cancer cachexia. We report in vitro and in vivo studies evaluating the preclinical pharmacologic profile of ANAM.

METHODS

Fluorescent imaging plate reader and binding assays in HEK293 and baby hamster kidney cells determined the agonist and antagonist activity of ANAM, and its affinity for the ghrelin receptor. Rat pituitary cells were incubated with ANAM to evaluate its effect on growth hormone (GH) release. In vivo, rats were treated with ANAM 3, 10, or 30 mg/kg, or control orally, once daily for 6 days to evaluate the effect on food intake (FI) and body weight (BW), and once to assess GH response. In pigs, single (3.5 mg/kg) or continuous (1 mg/kg/day) ANAM doses were administered to assess GH and insulin-like growth factor (IGF-1) response.

RESULTS

ANAM showed significant agonist and binding activity on the ghrelin receptor, and stimulated GH release in vitro. In rats, ANAM significantly and dose-dependently increased FI and BW at all dose levels compared with control, and significantly increased GH levels at 10 or 30 mg/kg doses. Increases in GH and IGF-1 levels were observed following ANAM administration in pigs.

CONCLUSION

ANAM is a potent and highly specific ghrelin receptor agonist with significant appetite-enhancing activity, leading to increases in FI and BW, and a stimulatory effect on GH secretion. These results support the continued investigation of ANAM as a potential treatment of cancer anorexia-cachexia syndrome.

Ghrelin relieves cancer cachexia associated with the development of lung adenocarcinoma in mice

Cancer cachexia is a multifactorial, critical illness syndrome characterized by an ongoing loss of skeletal muscle and adipose tissue. The reductions in body weight and skeletal muscle mass are important prognostic indicators for cancer patients that are refractory to current therapies. Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, is produced in the stomach, stimulates food intake and growth hormone secretion, suppresses inflammation, and prevents muscle catabolism. We investigated the pharmacological potential of ghrelin in the treatment of cancer cachexia by using urethane-treated, bronchioalveolar epithelium-specific Pten-deficient mice that developed lung adenocarcinomas. Ghrelin or phosphate-buffered saline was given to mice daily for four weeks beginning at five months after urethane injection, which corresponded to the time point of lung adenocarcinoma formation. Ghrelin inhibited the inductions of C-reactive protein, tumor necrosis factor-α, interleukin-1β, and interleukin-6, mitigated the reduction of food intake and fat mass, and consequently ameliorated body weight loss in the mouse model of lung adenocarcinoma. We also demonstrated that skeletal muscle mass and muscle contraction force in both fast-twitch muscle and slow-twitch muscle were retained in ghrelin-treated mice in conjunction with an upregulation of local insulin-like growth factor 1/Akt signaling. In addition, ghrelin administration reduced the expressions of phosphorylated-p38 mitogen-activated protein kinase, phosphorylated-nuclear factor-kappa B, Forkhead box protein O1, muscle RING-finger protein-1, and F-Box protein 32 in the lysates of skeletal muscle in the tumor-bearing state. Our results indicate that ghrelin administration exerts a protective effect against cancer cachexia by ameliorating skeletal muscle wasting and regulating systemic inflammation.

Ghrelin: from discovery to cancer cachexia therapy

PURPOSE OF REVIEW

Despite the high prevalence of cancer cachexia, a condition that negatively impacts patients' prognosis and quality of life, effective therapies are still lacking. Ghrelin is a peptide hormone involved in anabolic and homeostatic functions, whose mechanisms of action are still only partially clarified, but with promising positive effects in cancer cachexia. Recently, the therapeutic administration of ghrelin in cancer has been shown to counteract loss of body mass and function, including muscle, and we specifically focus on this novel evidence.

RECENT FINDINGS

Recent research aimed at developing new pharmacological therapies to prevent muscle wasting has used ghrelin and molecules acting as synthetic ghrelin receptor agonists with different modalities of administration and with high selectivity for specific targeted tissues. Positive effects of these therapies were described in cancer cachexia and chemotherapy-induced muscle wasting. New insights into the mechanisms of action of ghrelin revealed how its pleiotropic effects should be ascribed both to systemic anti-inflammation effect and to muscle-specific action through the activation of the antiatrophic molecular cascade.

SUMMARY

Growing interest arises from the identification of ghrelin as a valid and well tolerated therapeutic option to counteract structural and functional wasting derived from tumour growth.

Therapeutic implications of peptide interactions with G-protein-coupled receptors in diabetic vasculopathy

The dramatic worldwide increase in the prevalence of diabetes has generated an attempt by the scientific community to identify strategies for its treatment and prevention. Vascular dysfunction is a hallmark of diabetes and frequently leads to the development of atherosclerosis, coronary disease-derived myocardial infarction, stroke, peripheral arterial disease and diabetic 'triopathy' (retinopathy, nephropathy and neuropathy). These vascular complications, developing in an increasingly younger cohort of patients with diabetes, contribute to morbidity and mortality. Despite the development of new anti-diabetic or anti-hyperglycaemic drugs, vascular complications remain to be a problem. This warrants a need for new therapeutic strategies to tackle diabetic vasculopathy. There is a growing body of evidence showing that peptide-binding G-protein-coupled receptors (peptide-binding GPCRs) play an important role in the pathophysiology of vascular dysfunction during diabetes. Thus, in this review, we discuss some of the peptide-binding GPCRs involved in the regulation of vascular function that have potential to be a therapeutic target in the treatment of diabetic vasculopathy.

Anamorelin hydrochloride in the treatment of cancer anorexia-cachexia syndrome

Anamorelin hydrochloride is an orally active ghrelin receptor agonist in development by Helsinn, for the treatment of non-small-cell lung cancer (NSCLC) cachexia. In preclinical and clinical studies, the potent affinity of anamorelin for the ghrelin receptor is associated with significant appetite-enhancing activity and resultant improvements in body weight, lean body mass, and handgrip strength compared with placebo. The accompanying stimulatory effects on growth hormone and IGF-1 are not associated with tumor growth, and overall survival in patients with cancer is not compromised. Anamorelin is well tolerated with no dose-limiting toxicities identified to date. The findings of ongoing Phase III studies are needed to confirm the significant potential of anamorelin to treat NSCLC cachexia.