Pharmacodynamic hormonal effects of anamorelin, a novel oral ghrelin mimetic and growth hormone secretagogue in healthy volunteers

The efficacy and safety of anamorelin among patients with diabetes

BACKGROUND

Anamorelin is a selective ghrelin receptor agonist approved for cancer cachexia in Japan. Little is known about predictors of anamorelin efficacy. This study aimed to assess the effect of diabetes on the efficacy and safety of anamorelin in patients with cancer cachexia.

METHODS

Medical records of patients with advanced non-small-cell lung, gastric, pancreatic, or colorectal cancer who received anamorelin between January 2021 and March 2023 were retrospectively reviewed. The diabetic (DM) group included patients with a confirmed diagnosis of type 2 diabetes mellitus, random plasma glucose of ≥ 200 mg/dL, or hemoglobin A1c of ≥ 6.5%. The maximum body weight gain and adverse events during anamorelin administration were compared between the DM and non-DM groups. Patients with a maximum body weight gain ≥ 0 kg were classified as the responders.

RESULTS

Of 103 eligible patients, 31 (30.1%) were assigned to the DM group. The DM group gained less weight (median of -0.53% vs. + 3.00%, p < 0.01) and had fewer responders (45.2% vs. 81.9%, p < 0.01) than the non-DM group. The odds ratio for non-response in the DM group was 6.55 (95% confidential interval 2.37-18.06, p < 0.01), adjusted by age and performance status. The DM group had a higher cumulative incidence of hyperglycaemic adverse events (72.2% vs. 6.3%, p < 0.01) and more discontinuations due to hyperglycaemic adverse events (25.8% vs. 4.2%, p < 0.01) than the non-DM group.

CONCLUSIONS

Patients with diabetes and cancer cachexia are less likely to gain weight with anamorelin despite a high risk of hyperglycaemic adverse events.

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.

Biomarker endpoints in cancer cachexia clinical trials: Systematic Review 5 of the cachexia endpoint series

Regulatory agencies require evidence that endpoints correlate with clinical benefit before they can be used to approve drugs. Biomarkers are often considered surrogate endpoints. In cancer cachexia trials, the measurement of biomarkers features frequently. The aim of this systematic review was to assess the frequency and diversity of biomarker endpoints in cancer cachexia trials. A comprehensive electronic literature search of MEDLINE, Embase and Cochrane (1990-2023) was completed. Eligible trials met the following criteria: adults (≥18 years), prospective design, more than 40 participants, use of a cachexia intervention for more than 14 days and use of a biomarker(s) as an endpoint. Biomarkers were defined as any objective measure that was assayed from a body fluid, including scoring systems based on these assays. Routine haematology and biochemistry to monitor intervention toxicity were not considered. Data extraction was performed using Covidence, and reporting followed PRISMA guidance (PROSPERO: CRD42022276710). A total of 5975 studies were assessed, of which 52 trials (total participants = 6522) included biomarkers as endpoints. Most studies (n = 29, 55.7%) included a variety of cancer types. Pharmacological interventions (n = 27, 51.9%) were most evaluated, followed by nutritional interventions (n = 20, 38.4%). Ninety-nine different biomarkers were used across the trials, and of these, 96 were assayed from blood. Albumin (n = 29, 55.8%) was assessed most often, followed by C-reactive protein (n = 22, 42.3%), interleukin-6 (n = 16, 30.8%) and tumour necrosis factor-α (n = 14, 26.9%), the latter being the only biomarker that was used to guide sample size calculations. Biomarkers were explicitly listed as a primary outcome in six trials. In total, 12 biomarkers (12.1% of 99) were used in six trials or more. Insulin-like growth factor binding protein 3 (IGFBP-3) and insulin-like growth factor 1 (IGF-1) levels both increased significantly in all three trials in which they were both used. This corresponded with a primary outcome, lean body mass, and was related to the pharmacological mechanism. Biomarkers were predominately used as exploratory rather than primary endpoints. The most commonly used biomarker, albumin, was limited by its lack of responsiveness to nutritional intervention. For a biomarker to be responsive to change, it must be related to the mechanism of action of the intervention and/or the underlying cachexia process that is modified by the intervention, as seen with IGFBP-3, IGF-1 and anamorelin. To reach regulatory approval as an endpoint, the relationship between the biomarker and clinical benefit must be clarified.

Preoperative low skeletal muscle volume can result in insufficient administration of S-1 adjuvant chemotherapy in older patients with stage II/III gastric cancer

BACKGROUND AND PURPOSE

Older patients are more likely to encounter difficulties receiving chemotherapy, but the factors involved in the continuation of chemotherapy in these patients remain unclear. We investigated the importance of muscle mass as a factor involved in delivering a sufficient dose of postoperative S-1 adjuvant chemotherapy (ACT) to older patients with gastric cancer.

METHODS

The subjects of this study were 79 patients aged ≥ 65 years with stage II/III gastric adenocarcinoma, who underwent curative gastrectomy and received S-1 ACT.

RESULTS

The overall median relative dose intensity (RDI) was 75.0% (18.8-93.5%). Patients were divided into two groups for receiver operating characteristic analysis according to the cutoff value. Significantly more patients in the high skeletal muscle index (SMI) group achieved > 62% RDI of S-1 ACT (p = 0.03). Conversely, more patients in the low SMI group suffered from S-1-induced nausea (p = 0.03) and discontinued chemotherapy because of adverse events (p = 0.02). Multivariate analysis identified low SMI as an independent factor for insufficient S-1 dose delivery (p = 0.03, hazard ratio = 2.87).

CONCLUSION

Preoperative SMI is an indicator of the low-dose intensity of S-1 ACT in older patients following curative gastrectomy.

Effect of Anamorelin, a Ghrelin Receptor Agonist, on Muscle and Bone in Adults With Osteosarcopenia

CONTEXT

Anamorelin, a ghrelin receptor agonist known to stimulate the pulsatile release of GH from the pituitary, has the potential to improve musculoskeletal health in adults with osteosarcopenia.

OBJECTIVE

To determine the effect of anamorelin treatment for 1 year on muscle mass and strength and on biochemical markers of bone turnover in adults with osteosarcopenia (OS).

DESIGN

Randomized, placebo-controlled, 1-year anamorelin intervention trial.

SETTING

The Bone Metabolism Laboratory at the USDA Nutrition Center at Tufts University.

PARTICIPANTS

26 men and women, age 50 years and older, with OS.

MAIN OUTCOME MEASURES

Muscle mass by D3-creatine dilution and lean body mass (LBM) and bone mineral density (BMD) by dual-energy X-ray absorptiometry, muscle strength, serum IGF-1, and bone turnover markers, serum procollagen 1 intact N-terminal (P1NP), and C-terminal telopeptide (CTX).

RESULTS

Anamorelin did not have a significant effect on muscle mass or LBM; it significantly increased knee flexion torque at 240°/s by 20% (P = .013) and had a similar nonstatistically significant effect on change in knee extension; it increased bone formation (P1NP) by 75% (P = .006) and had no significant effect on bone resorption (CTX) or BMD. Serum IGF-1 increased by 50% in the anamorelin group and did not change in the placebo group (P = .0001 for group difference).

CONCLUSION

In this pilot study, anamorelin did not significantly alter muscle mass; however, it may potentially improve lower extremity strength and bone formation in addition to increasing circulating IGF-1 levels in adults with OS. Further study of anamorelin in this population is warranted.

Predictors of efficacy of anamorelin in patients with non‑small cell lung cancer and cachexia: A retrospective study

Anamorelin, a ghrelin receptor agonist, is approved in Japan for the treatment of cachexia in patients with lung and gastrointestinal cancer. However, there is limited research on the usefulness of anamorelin in clinical settings, therefore, the present study evaluated its efficacy using patient characteristics. A total of 40 patients with non-small cell lung cancer and cachexia who were prescribed anamorelin in the Department of Respiratory Medicine, Hirosaki University Graduate School of Medicine (Aomori, Japan) between July 2021 and November 2022, were retrospectively assessed. Anamorelin was prescribed at a dose of 100 mg once daily to patients who had lost >5% of their body weight within 6 months. All patients were weighed before treatment and those who continued anamorelin treatment for 12 weeks were also weighed at 12 weeks. A logistic regression analysis was used to analyze the association between background characteristics and early discontinuation of treatment with anamorelin (within 4 weeks). The median age was 67 years (range, 36-88), and 65% of the patients were male. There were 24 patients (60.0%) with an Eastern Cooperative Oncology Group Performance Status (ECOG-PS) score 1, 11 patients (27.5%) with an ECOG-PS score 2 and five patients (12.5%) with an ECOG-PS score 3. The early discontinuation group included 11 patients (27.5%). An ECOG-PS score ≥2 (odds ratio, 7.85; 95% confidence interval, 1.43-43.21; P=0.018) was associated with early discontinuation. A total of 18/40 patients (45.0%) were able to continue anamorelin treatment for 12 weeks, and the mean change in body weight was +2.31 kg, which was a significant change from the weight recorded at baseline (P=0.027). The mean changes in lean body mass and soft lean mass between baseline and 12 weeks were +1.97 kg (P=0.14) and +1.26 kg (P=0.15), respectively. The results from the present study indicate that anamorelin is unlikely to be useful for patients with a poor general condition (ECOG-PS score ≥2).

Exploring Metabolic Pathways of Anamorelin, a Selective Agonist of the Growth Hormone Secretagogue Receptor, via Molecular Networking

In this study, we delineated the poorly characterized metabolism of anamorelin, a growth hormone secretagogue receptor agonist, in vitro using human liver microsomes (HLM), based on classical molecular networking (MN) and feature-based molecular networking (FBMN) from the Global Natural Products Social Molecular Networking platform. Following the in vitro HLM reaction, the MN analysis showed 11 neighboring nodes whose information propagated from the node corresponding to anamorelin. The FBMN analysis described the separation of six nodes that the MN analysis could not achieve. In addition, the similarity among neighboring nodes could be discerned via their respective metabolic pathways. Collectively, 18 metabolites (M1-M12) were successfully identified, suggesting that the metabolic pathways involved were demethylation, hydroxylation, dealkylation, desaturation, and N-oxidation, whereas 6 metabolites (M13a*-b*, M14a*-b*, and M15a*-b*) remained unidentified. Furthermore, the major metabolites detected in HLM, M1 and M7, were dissimilar from those observed in the CYP3A4 isozyme assay, which is recognized to be markedly inhibited by anamorelin. Specifically, M7, M8, and M9 were identified as the major metabolites in the CYP3A4 isozyme assay. Therefore, a thorough investigation of metabolism is imperative for future in vivo studies. These findings may offer prospective therapeutic opportunities for anamorelin.

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.

Cancer Cachexia: Underlying Mechanisms and Potential Therapeutic Interventions

Cancer cachexia, a multifactorial metabolic syndrome developed during malignant tumor growth, is characterized by an accelerated loss of body weight accompanied by the depletion of skeletal muscle mass. This debilitating condition is associated with muscle degradation, impaired immune function, reduced functional capacity, compromised quality of life, and diminished survival in cancer patients. Despite the lack of the known capability of fully reversing or ameliorating this condition, ongoing research is shedding light on promising preclinical approaches that target the disrupted mechanisms in the pathophysiology of cancer cachexia. This comprehensive review delves into critical aspects of cancer cachexia, including its underlying pathophysiological mechanisms, preclinical models for studying the progression of cancer cachexia, methods for clinical assessment, relevant biomarkers, and potential therapeutic strategies. These discussions collectively aim to contribute to the evolving foundation for effective, multifaceted counteractive strategies against this challenging condition.

Efficacy and safety of anamorelin in patients with cancer cachexia: Post-hoc subgroup analyses of a placebo-controlled study

BACKGROUND

Cachexia, a disorder associated with anorexia, inflammation, and muscle wasting, is frequent in cancer patients. We performed post-hoc analyses of the ONO-7643-04 study to investigate the efficacy and safety of anamorelin in subgroups of Japanese patients with non-small cell lung cancer (NSCLC).

METHODS

The patients were divided into subgroups by baseline characteristics, including sex, age, body mass index, prior weight loss, performance status (PS), concomitant anticancer therapy, and number of previous chemotherapy regimens. The changes from baseline through to 12 weeks for lean body mass (LBM), body weight, and appetite were calculated. Appetite was evaluated using the quality of life questionnaire for cancer patients treated with anticancer drugs (QOL-ACD) item 8 score. Responder rates were defined as the maintenance/improvement of LBM (≥0 kg), body weight (≥0 kg), or QOL-ACD item 8 score (≥0) from baseline to all evaluation time points. Safety was evaluated in patients subgrouped by age and PS.

RESULTS

Anamorelin resulted in greater improvements versus placebo in LBM, body weight, and appetite in most subgroups. Anamorelin was also associated with greater LBM, body weight, and appetite responder rates than placebo in nearly all subgroups. Among anamorelin-treated patients, adverse drug reactions (ADRs) tended to be more frequent with increasing age (<65 years, 19.2%; ≥65 to <75 years, 45.9%; ≥75 years, 60.0%) and PS score (PS 0-1, 38.4%; PS 2, 60.0%). The frequency of serious ADRs was 2.7% and 0% in the PS 0-1 and PS 2 subgroups, respectively.

CONCLUSION

This study of NSCLC patients with cancer cachexia revealed consistent improvements in LBM, body weight, and appetite across most subgroups of anamorelin-treated patients. This study also demonstrated the tolerability of anamorelin regardless of age and PS, with a low incidence of serious ADRs in each subgroup.

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.

Role of the Ghrelin System in Colorectal Cancer

The ghrelin system contains several components (e.g., ghrelin with growing number of alternative peptides, growth hormone secretagogue receptors (GHS-Rs), and ghrelin-O-acyl-transferase (GOAT) and participates in regulation of a number of key processes of gastrointestinal (GI) tract cancer progression, including cell proliferation, migration, invasion, apoptosis, inflammation, and angiogenesis. However, its exact role in promoting or inhibiting cancer progression is still unclear. Colorectal cancer (CRC) is one of the most common human malignancies worldwide. Molecular studies suggest an autocrine/paracrine mechanism for the secretion of ghrelin in colorectal carcinogenesis and its contribution to its initial stages. However, the signalling pathways of CRC development involving the ghrelin system are poorly understood. Potential mechanisms of colon carcinogenesis involving components of the ghrelin system were previously described in an animal model and in in vitro studies. However, the diagnostic–prognostic role of serum ghrelin concentrations, tissue expression, or genetic changes of this system in various stages of CRC progression remains an open case. Thus, the aim of this study is to discuss the role of the ghrelin system in colon carcinogenesis, diagnostics and CRC prognostics, as well as the results of studies on the use of ghrelin and its analogues in the therapy of CRC-related syndromes (e.g., cachexia and sarcopenia).

Evolution of Systemic Therapy in Metastatic Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma is characterized by early systemic dissemination, a complex tumor microenvironment, as well as significant intratumoral and intertumoral heterogeneity. Treatment options and survival in pancreatic ductal adenocarcinoma have improved steadily over the last 3 decades. Although cytotoxic chemotherapy is currently the mainstay of treatment for pancreatic ductal adenocarcinoma, evolving therapeutic strategies are aimed at targeting the tumor microenvironment, metabolism, and the tumor-host immune balance.

Food, Nutrition, Physical Activity and Microbiota: Which Impact on Lung Cancer?

Lung cancer still represents the leading cause of cancer-related death, globally. Likewise, malnutrition and inactivity represent a major risk for loss of functional pulmonary capacities influencing overall lung cancer severity. Therefore, the adhesion to an appropriate health lifestyle is crucial in the management of lung cancer patients despite the subtype of cancer. This review aims to summarize the available knowledge about dietary approaches as well as physical activity as the major factors that decrease the risk towards lung cancer, and improve the response to therapies. We discuss the most significant dietary schemes positively associated to body composition and prognosis of lung cancer and the main molecular processes regulated by specific diet schemes, functional foods and physical activity, i.e., inflammation and oxidative stress. Finally, we report evidence demonstrating that dysbiosis of lung and/or gut microbiome, as well as their interconnection (the gut–lung axis), are strictly related to dietary patterns and regular physical activity playing a key role in lung cancer formation and progression, opening to the avenue of modulating the microbiome as coadjuvant therapy. Altogether, the evidence reported in this review highlights the necessity to consider non-pharmacological interventions (nutrition and physical activity) as effective adjunctive strategies in the management of lung cancer.

Effects of microbiome changes on endocrine ghrelin signaling - A systematic review

The 28-amino acid peptide hormone ghrelin plays a unique role in the gut-brain axis: It is mainly produced peripherally in gastric X/A-like cells but stimulates food intake centrally via hypothalamic nuclei; thus, providing orexigenic communication between the gut and central food intake-regulatory centers. Another component of the gut-brain axis that gained increasing interest in recent years due to its ability to influence central signaling via metabolites is the gut microbiome. Interestingly, there is increasing evidence that changes in the microbiome are related to alterations in ghrelin expression, secretion, activation and signaling. Since ghrelin is supposedly implicated in the pathogenesis of obesity, changes in the microbiome were hypothesized to improve obesity via modulation of ghrelin abundance and receptor interaction. To shed more light on the association between the microbiome and ghrelin a systematic search of Medline, EMBASE and Web of science using the search term combination "microbiome AND ghrelin" was performed. As a result of the search, 42 publications were included into this systematic review, of which 30 publications reported preclinical and 12 manuscripts presented clinical data. In addition to a critical analysis of the present data, gaps in knowledge were highlighted in order to foster further research.

Uremic Sarcopenia: Clinical Evidence and Basic Experimental Approach

Sustained physical activity extends healthy life years while a lower activity due to sarcopenia can reduce them. Sarcopenia is defined as a decrease in skeletal muscle mass and strength due not only to aging, but also from a variety of debilitating chronic illnesses such as cancer and heart failure. Patients with chronic kidney disease (CKD), who tend to be cachexic and in frail health, may develop uremic sarcopenia or uremic myopathy due to an imbalance between muscle protein synthesis and catabolism. Here, we review clinical evidence indicating reduced physical activity as renal function deteriorates and explore evidence-supported therapeutic options focusing on nutrition and physical training. In addition, although sarcopenia is a clinical concept and difficult to recapitulate in basic research, several in vivo approaches have been attempted, such as rodent subtotal nephrectomy representing both renal dysfunction and muscle weakness. This review highlights molecular mechanisms and promising interventions for uremic sarcopenia that were revealed through basic research. Extensive study is still needed to cast light on the many aspects of locomotive organ impairments in CKD and explore the ways that diet and exercise therapies can improve both outcomes and quality of life at every level.

Appetite and food intake results from phase I studies of anamorelin

BACKGROUND

Loss of appetite and body weight are potentially devastating, highly prevalent cancer complications. The ghrelin receptor is a mediator of appetite and metabolism, and anamorelin is a novel, orally administered ghrelin receptor agonist. Effects on appetite and food intake may influence body-weight gain but can be difficult to measure in multi-site studies. Here, we summarize two single-centre trials.

METHODS

Both trials were phase I, randomized, double-blind, placebo-controlled, partly/wholly crossover studies of healthy young adults. Study 102 tested single anamorelin doses of 1-20 mg. Assessments included post-dose self-ratings on 100 mm visual analogue scales for hunger, anticipated eating pleasure, and anticipated quantity of food consumption. Study 101 tested single 10, 25, and 50 mg doses. Assessments included the same scales plus caloric intake beginning 4 h post-dose.

RESULTS

Study 102 treated 16 male subjects (mean age, 26.3 years). Mean hunger scores generally increased after all treatments, with significant differences from placebo (P < 0.05) in the 5 mg anamorelin group at 0.5 and 1 h post-dose (+8.2 and +13.2 mm). Results for other scales were similar. Study 101 treated nine male subjects (mean age, 26.3 years). Pooled findings for anamorelin 25 and 50 mg vs. placebo showed significant mean increases in hunger scores at all but 1 pre-prandial time point, including the first assessment, 0.5 h post-dose (+10.9 vs. +0.7 mm, P = 0.0077), and the last assessment, 4 h post-dose (+32.7 vs. +7.0 mm, P = 0.0170), with a significant mean 18.4% increase vs. placebo in caloric intake (P = 0.0148).

CONCLUSIONS

In single-centre studies of healthy adults, single anamorelin doses of 1-20 mg elicited modest increases in hunger, and single doses of 25 and 50 mg achieved significant increases in hunger and caloric intake. The findings are consistent with dose-related weight gain reported in a prior phase I study as well as multi-centre findings in cachectic cancer patients and expand the evidence supporting anamorelin as a potential intervention.

Pharmacological Modulation of Ghrelin to Induce Weight Loss: Successes and Challenges

PURPOSE OF REVIEW

Obesity is affecting over 600 million adults worldwide and has numerous negative effects on health. Since ghrelin positively regulates food intake and body weight, targeting its signaling to induce weight loss under conditions of obesity seems promising. Thus, the present work reviews and discusses different possibilities to alter ghrelin signaling.

RECENT FINDINGS

Ghrelin signaling can be altered by RNA Spiegelmers, GHSR/Fc, ghrelin-O-acyltransferase inhibitors as well as antagonists, and inverse agonists of the ghrelin receptor. PF-05190457 is the first inverse agonist of the ghrelin receptor tested in humans shown to inhibit growth hormone secretion, gastric emptying, and reduce postprandial glucose levels. Effects on body weight were not examined. Although various highly promising agents targeting ghrelin signaling exist, so far, they were mostly only tested in vitro or in animal models. Further research in humans is thus needed to further assess the effects of ghrelin antagonism on body weight especially under conditions of obesity.

Sarcopenic obesity in older adults: aetiology, epidemiology and treatment strategies

The prevalence of obesity in combination with sarcopenia (the age-related loss of muscle mass and strength or physical function) is increasing in adults aged 65 years and older. A major subset of adults over the age of 65 is now classified as having sarcopenic obesity, a high-risk geriatric syndrome predominantly observed in an ageing population that is at risk of synergistic complications from both sarcopenia and obesity. This Review discusses pathways and mechanisms leading to muscle impairment in older adults with obesity. We explore sex-specific hormonal changes, inflammatory pathways and myocellular mechanisms leading to the development of sarcopenic obesity. We discuss the evolution, controversies and challenges in defining sarcopenic obesity and present current body composition modalities used to assess this condition. Epidemiological surveys form the basis of defining its prevalence and consequences beyond comorbidity and mortality. Current treatment strategies, and the evidence supporting them, are outlined, with a focus on calorie restriction, protein supplementation and aerobic and resistance exercises. We also describe weight loss-induced complications in patients with sarcopenic obesity that are relevant to clinical management. Finally, we review novel and potential future therapies including testosterone, selective androgen receptor modulators, myostatin inhibitors, ghrelin analogues, vitamin K and mesenchymal stem cell therapy.

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.

Anamorelin (ONO-7643) for the treatment of patients with non-small cell lung cancer and cachexia: Results from a randomized, double-blind, placebo-controlled, multicenter study of Japanese patients (ONO-7643-04)

BACKGROUND

Cachexia, described as weight loss (mainly in lean body mass [LBM]) and anorexia, is common in patients with advanced cancer. This study examined the efficacy and safety of anamorelin (ONO-7643), a novel selective ghrelin receptor agonist, in Japanese cancer patients with cachexia.

METHODS

This double-blind clinical trial (ONO-7643-04) enrolled 174 patients with unresectable stage III/IV non-small cell lung cancer (NSCLC) and cachexia in Japan. Patients were randomized to daily oral anamorelin (100 mg) or a placebo for 12 weeks. The primary endpoint was the change from the baseline LBM (measured with dual-energy x-ray absorptiometry) over 12 weeks. The secondary endpoints were changes in appetite, body weight, quality of life, handgrip strength (HGS), and 6-minute walk test (6MWT) results.

RESULTS

The least squares mean change (plus or minus the standard error) in LBM from the baseline over 12 weeks was 1.38 ± 0.18 and -0.17 ± 0.17 kg in the anamorelin and placebo groups, respectively (P < .0001). Changes from the baseline in LBM, body weight, and anorexia symptoms showed significant differences between the 2 treatment groups at all time points. Anamorelin increased prealbumin at weeks 3 and 9. No changes in HGS or 6MWT were detected between the groups. Twelve weeks' treatment with anamorelin was safe and well tolerated in NSCLC patients.

CONCLUSIONS

Anamorelin significantly increased LBM and improved anorexia symptoms and the nutritional state, but not motor function, in Japanese patients with advanced NSCLC. Because no effective treatment for cancer cachexia is currently available, anamorelin can be a beneficial treatment option. Cancer 2018;124:606-16. © 2017 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

What is next after anamorelin?

PURPOSE OF REVIEW

In spite of its relevance, treatments for the cancer anorexia and cachexia syndrome (CACS) are not available. One of the agents that recently reached phase III clinical trials is anamorelin. Its development, along with that of other agents for this indication, will be reviewed here, with a focus on the gaps in the current knowledge and future directions.

RECENT FINDINGS

In spite of several targets showing promising results in early development, their difficulties obtaining regulatory approval underscore the need to reconsider the current strategies in drug development and the challenges in the field of CACS.

SUMMARY

Further research is needed in order to meet the challenges of developing treatments for CACS. Preclinical studies should expand our understanding about key regulators of appetite, muscle, and energy metabolism in this setting using models that can be translated reliably to humans. Clinical research efforts should focus on validating the entry criteria, endpoints, outcomes, and the potential synergistic effects and interaction between different targets, nutrition, and exercise interventions. Clinical meaningfulness and significance should be taken into account in the design of clinical trials. It is essential that all key stakeholders are included in the design of future strategies.

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.

Deletion of ghrelin prevents aging-associated obesity and muscle dysfunction without affecting longevity

During aging, decreases in energy expenditure and locomotor activity lead to body weight and fat gain. Aging is also associated with decreases in muscle strength and endurance leading to functional decline. Here, we show that lifelong deletion of ghrelin prevents development of obesity associated with aging by modulating food intake and energy expenditure. Ghrelin deletion also attenuated the decrease in phosphorylated adenosine monophosphate‐activated protein kinase (pAMPK) and downstream mediators in muscle, and increased the number of type IIa (fatigue resistant, oxidative) muscle fibers, preventing the decline in muscle strength and endurance seen with aging. Longevity was not affected by ghrelin deletion. Treatment of old mice with pharmacologic doses of ghrelin increased food intake, body weight, and muscle strength in both ghrelin wild‐type and knockout mice. These findings highlight the relevance of ghrelin during aging and identify a novel AMPK‐dependent mechanism for ghrelin action in muscle.

From Belly to Brain: Targeting the Ghrelin Receptor in Appetite and Food Intake Regulation

Ghrelin is the only known peripherally-derived orexigenic hormone, increasing appetite and subsequent food intake. The ghrelinergic system has therefore received considerable attention as a therapeutic target to reduce appetite in obesity as well as to stimulate food intake in conditions of anorexia, malnutrition and cachexia. As the therapeutic potential of targeting this hormone becomes clearer, it is apparent that its pleiotropic actions span both the central nervous system and peripheral organs. Despite a wealth of research, a therapeutic compound specifically targeting the ghrelin system for appetite modulation remains elusive although some promising effects on metabolic function are emerging. This is due to many factors, ranging from the complexity of the ghrelin receptor (Growth Hormone Secretagogue Receptor, GHSR-1a) internalisation and heterodimerization, to biased ligand interactions and compensatory neuroendocrine outputs. Not least is the ubiquitous expression of the GHSR-1a, which makes it impossible to modulate centrally-mediated appetite regulation without encroaching on the various peripheral functions attributable to ghrelin. It is becoming clear that ghrelin’s central signalling is critical for its effects on appetite, body weight regulation and incentive salience of food. Improving the ability of ghrelin ligands to penetrate the blood brain barrier would enhance central delivery to GHSR-1a expressing brain regions, particularly within the mesolimbic reward circuitry.

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.

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.

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.

F-BOX proteins in cancer cachexia and muscle wasting: Emerging regulators and therapeutic opportunities

Cancer cachexia is a debilitating metabolic syndrome accounting for fatigue, an impairment of normal activities, loss of muscle mass associated with body weight loss eventually leading to death in majority of patients with advanced disease. Cachexia patients undergoing skeletal muscle atrophy show consistent activation of the SCF ubiquitin ligase (F-BOX) family member Atrogin-1 (also known as MAFBx/FBXO32) alongside the activation of the muscle ring finger protein1 (MuRF1). Other lesser known F-BOX family members are also emerging as key players supporting muscle wasting pathways. Recent work highlights a spectrum of different cancer signaling mechanisms impacting F-BOX family members that feed forward muscle atrophy related genes during cachexia. These novel players provide unique opportunities to block cachexia induced skeletal muscle atrophy by therapeutically targeting the SCF protein ligases. Conversely, strategies that induce the production of proteins may be helpful to counter the effects of these F-BOX proteins. Through this review, we bring forward some novel targets that promote atrogin-1 signaling in cachexia and muscle wasting and highlight newer therapeutic opportunities that can help in the better management of patients with this devastating and fatal disorder.

Site and mechanism of the colokinetic action of the ghrelin receptor agonist, HM01

BACKGROUND

It has been recently demonstrated that the ghrelin receptor agonist, HM01, caused defecation in rats that were treated to provide a model for the constipation of Parkinson's disease. HM01 significantly increased fecal output and increased Fos activity in neurons of the hypothalamus and hindbrain, but not in the spinal defecation center. Other ghrelin agonists act on the defecation center.

METHODS

Receptor pharmacology was examined in ghrelin receptor (GHSR1a) transfected cells. Anesthetized rats were used to investigate sites and mechanisms of action.

KEY RESULTS

HM01 activated rat GHSR1a at nanomolar concentrations and was antagonized by the GHSR1a antagonist, YIL781. HM01, intravenous, was potent to activate propulsive colorectal contractions. This was prevented by pelvic nerve section and by intravenous YIL781, but not by spinal cord section rostral to the defecation centers. Direct intrathecal application of HM01 to the defecation center at spinal level L6-S1 initiated propulsive contractions of the colorectum.

CONCLUSIONS & INFERENCES

HM01 stimulates GHSR1a receptors on neurons in the lumbosacral defecation centers to cause propulsive contractions and emptying of the colorectum. It has greater potency when given systemically, compared with other GHSR1a agonists.

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.

Opportunities for targeting the fatigue-anorexia-cachexia symptom cluster

Cancer patients experience multiple symptoms throughout their illness trajectory. Symptoms consistently occurring together, known as symptom clusters, share common pathophysiologic mechanisms. Understanding and targeting such symptom clusters may allow for more effective and efficient use of treatments for a variety of symptoms. Fatigue-anorexia-cachexia is one of the most prevalent symptom clusters and significantly impairs quality of life. In this review, we explore the fatigue-anorexia-cachexia symptom cluster and focus on current and emerging therapies with an emphasis on pharmacologic management.

Ghrelin prevents tumour- and cisplatin-induced muscle wasting: characterization of multiple mechanisms involved

BACKGROUND

Cachexia and muscle atrophy are common consequences of cancer and chemotherapy administration. The novel hormone ghrelin has been proposed as a treatment for this condition. Increases in food intake and direct effects on muscle proteolysis and protein synthesis are likely to mediate these effects, but the pathways leading to these events are not well understood.

METHODS

We characterized molecular pathways involved in muscle atrophy induced by Lewis lung carcinoma (LLC) tumour implantation in c57/bl6 adult male mice and by administration of the chemotherapeutic agent cisplatin in mice and in C2C12 myotubes. The effects of exogenous ghrelin administration and its mechanisms of action were examined in these settings.

RESULTS

Tumour implantation and cisplatin induced muscle atrophy by activating pro-inflammatory cytokines, p38-C/EBP-β, and myostatin, and by down-regulating Akt, myoD, and myogenin, leading to activation of ubiquitin-proteasome-mediated proteolysis and muscle weakness. Tumour implantation also increased mortality. In vitro, cisplatin up-regulated myostatin and atrogin-1 by activating C/EBP-β and FoxO1/3. Ghrelin prevented these changes in vivo and in vitro, significantly increasing muscle mass (P < 0.05 for LLC and P < 0.01 for cisplatin models) and grip strength (P = 0.038 for LLC and P = 0.001 for cisplatin models) and improving survival (P = 0.021 for LLC model).

CONCLUSION

Ghrelin prevents muscle atrophy by down-regulating inflammation, p38/C/EBP-β/myostatin, and activating Akt, myogenin, and myoD. These changes appear, at least in part, to target muscle cells directly. Ghrelin administration in this setting is associated with improved muscle strength and survival.

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.

Muscle wasting in disease: molecular mechanisms and promising therapies

Atrophy occurs in specific muscles with inactivity (for example, during plaster cast immobilization) or denervation (for example, in patients with spinal cord injuries). Muscle wasting occurs systemically in older people (a condition known as sarcopenia); as a physiological response to fasting or malnutrition; and in many diseases, including chronic obstructive pulmonary disorder, cancer-associated cachexia, diabetes, renal failure, cardiac failure, Cushing syndrome, sepsis, burns and trauma. The rapid loss of muscle mass and strength primarily results from excessive protein breakdown, which is often accompanied by reduced protein synthesis. This loss of muscle function can lead to reduced quality of life, increased morbidity and mortality. Exercise is the only accepted approach to prevent or slow atrophy. However, several promising therapeutic agents are in development, and major advances in our understanding of the cellular mechanisms that regulate the protein balance in muscle include the identification of several cytokines, particularly myostatin, and a common transcriptional programme that promotes muscle wasting. Here, we discuss these new insights and the rationally designed therapies that are emerging to combat muscle wasting.

An open-label clinical trial of the effects of age and gender on the pharmacodynamics, pharmacokinetics and safety of the ghrelin receptor agonist anamorelin

PURPOSE

To assess the effect of age and gender on the pharmacokinetics (PK) of the ghrelin receptor agonist anamorelin.

METHODS

Three demographic cohorts of healthy subjects were enrolled in this single-center, open-label study. Subjects received a single oral dose (25 mg) of anamorelin HCl. Serial blood samples were collected over 24 hours to assess anamorelin PK and circulating growth hormone (GH) levels. Data were compared with a reference cohort.

RESULTS

Anamorelin was rapidly absorbed in all cohorts; peak concentrations were observed 30-45 minutes and 2-4 hours post-dose, which declined biexponentially with mean terminal half-lives of 6-7 hours. An age effect on C_max and AUC_∞ was not apparent; however, mean AUC_∞ values were approximately 1.8-1.9-fold higher in the female cohorts than in the reference male cohort. GH increase was rapid and virtually identical in both sexes, though attenuated in elderly subjects. No clinically significant safety or tolerability findings were observed.

CONCLUSIONS

While PK parameters do suggest higher exposure in females, this effect is considered to be modest given the variability of the 6-8 subjects per cohort. Moreover, no such effect was observed in the pharmacodynamic responses, thus, dose adjustment for age and gender is considered unnecessary.

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.

Possible synergism of physical exercise and ghrelin-agonists in patients with cachexia associated with chronic heart failure

The occurrence of cachexia of multifactorial etiology in chronic heart failure (CHF) is a common and underestimated condition that usually leads to poor outcome and low survival rates, with high direct and indirect costs for the Health Care System. Recently, a consensus definition on cachexia has been reached, leading to a growing interest by the scientific community in this condition, which characterizes the last phase of many chronic diseases (i.e., cancer, acquired immunodeficiency syndrome). The etiology of cachexia is multifactorial and the underlying pathophysiological mechanisms are essentially the following: anorexia and malnourishment; immune overactivity and systemic inflammation; and endocrine disorders (anabolic/catabolic imbalance and resistance to growth hormone). In this paper, we review the main pathophysiological mechanisms underlying CHF cachexia, focusing also on the broad spectrum of actions of ghrelin and ghrelin agonists, and their possible use in combination with physical exercise to contrast CHF cachexia.

Ghrelin receptor modulators: a patent review (2011 - 2014)

INTRODUCTION

Over the past 3 years, several patents appeared dealing with the discovery of compounds able to modulate ghrelin actions: agonists for the treatment of cachexia, as diagnostic agents for GH deficiency or for the increase in gastrointestinal motility, antagonists and inverse agonists as anorexigenic agents for the treatment of obesity and type 2 diabetes. This research has been conducted by several pharmaceutical companies and some compounds have entered clinical trials, but, to date, compounds acting on the ghrelin receptor do not represent clinical options yet.

AREAS COVERED

A comprehensive description and categorization of patents related to each type of compounds is provided, together with data related to these compounds that appeared in the scientific literature.

EXPERT OPINION

Ghrelin appears to mediate a myriad of actions, and some of these appear to be due to unknown mechanisms (a second putative ghrelin receptor, putative receptors for unacylated ghrelin); several agonists, antagonists and inverse agonists at ghrelin receptor have been developed but their mechanism of action into CNS is poorly understood. The therapeutic potential of compounds acting on ghrelin receptor is still to be fully assessed, but the results obtained to date are encouraging for the successful clinical translation of compounds able to treat several pathologies.

Clinical development of ghrelin axis-derived molecules for cancer cachexia treatment

PURPOSE OF REVIEW

Cachexia is a devastating complication of cancer for which there is no approved treatment. Here we review the clinical development of ghrelin and ghrelin mimetics (also known as growth hormone secretagogues or GHS) for cancer cachexia treatment.

RECENT FINDINGS

Ghrelin, a novel hormone known to increase appetite, lean and fat mass, and growth hormone secretion, is being developed as a therapeutic option for cancer anorexia-cachexia syndrome (CACS). Recent animal studies suggest that it may also decrease inflammation and that some of its effects may be independent of its only known receptor, the GHS receptor-1a.Clinical studies recently have shown that administration of ghrelin or GHS improves appetite and quality of life as assessed by questionnaires. Weight gain, increased food intake and better tolerance to chemotherapy have also been reported. This treatment appears to be safe and well tolerated.

SUMMARY

Ghrelin and GHS have the potential to effectively prevent or reverse CACS. Preliminary studies show improvements in weight stabilization and appetite with short-term usage. Further studies are required to fully characterize the role of ghrelin and GHS for the treatment of CACS and to establish the safety of this approach.

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.

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

Purpose

Anamorelin (ONO-7643) is an orally active ghrelin receptor agonist in development for non-small cell lung cancer (NSCLC)-related anorexia/cachexia. It displays both orexigenic and anabolic properties via ghrelin mimetic activity and transient increases in growth hormone (GH). However, increasing GH and insulin-like growth factor-1 in cancer patients raises concerns of potentially stimulating tumor growth. Therefore, we investigated the effect of ghrelin and anamorelin on tumor growth in a murine NSCLC xenograft model.

Methods

Female nude mice (15–21/group) with established A549 tumors were administered ghrelin (2 mg/kg i.p.), anamorelin (3, 10, or 30 mg/kg p.o.), or vehicle controls daily for 28 days. Tumor growth, food consumption, and body weight were monitored. Murine growth hormone (mGH) and murine insulin-like growth factor-1 (mIGF-1) were measured in plasma.

Results

Tumor growth progressed throughout the study, with no significant differences between treatment groups. Daily food consumption was also relatively unchanged, while the percentage of mean body weight gain at the end of treatment was significantly increased in animals administered 10 and 30 mg/kg compared with controls (p < 0.01). Peak mGH levels were significantly higher in ghrelin- and anamorelin-treated animals than in controls, while peak mIGF-1 levels were slightly elevated but not statistically significant. All regimens were well tolerated.

Conclusions

These findings demonstrate that neither anamorelin nor ghrelin promoted tumor growth in this model, despite increased levels of mGH and a trend of increased mIGF-1. Together with anamorelin’s ability to increase body weight, these results support the clinical development of ghrelin receptor agonist treatments for managing NSCLC-related anorexia/cachexia.

Treatment of cachexia: melanocortin and ghrelin interventions

Cachexia is a condition typified by wasting of fat and LBM caused by anorexia and further endocrinological modulation of energy stores. Diseases known to cause cachectic symptoms include cancer, chronic kidney disease, and chronic heart failure; these conditions are associated with increased levels of proinflammatory cytokines and increased resting energy expenditure. Early studies have suggested the central melanocortin system as one of the main mediators of the symptoms of cachexia. Pharmacological and genetic antagonism of these pathways attenuates cachectic symptoms in laboratory models; effects have yet to be studied in humans. In addition, ghrelin, an endogenous orexigenic hormone with receptors on melanocortinergic neurons, has been shown to ameliorate symptoms of cachexia, at least in part, by an increase in appetite via melanocortin modulation, in addition to its anticatabolic and anti-inflammatory effects. These effects of ghrelin have been confirmed in multiple types of cachexia in both laboratory and human studies, suggesting a positive future for cachexia treatments.