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BackgroundAnamorelin 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.MethodsFluorescent 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.ResultsANAM 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.ConclusionANAM 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.

PurposeAnamorelin (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.MethodsFemale 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.ResultsTumor 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.ConclusionsThese 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.

Granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting tumor vaccines are bioactive, but limited by disease burden and immune tolerance. Cyclophosphamide (CY) augments vaccine activity in tolerant neu mice and metastatic breast cancer (MBC) patients. HER-2-specific monoclonal antibodies (MAb) enhance vaccine activity in neu mice. We hypothesized that CY-modulated vaccination with HER-2-specific MAb safely induces relevant HER-2-specific immunity in neu mice and HER-2+ MBC patients. Adding both CY and the HER-2-specific MAb 7.16.4 to vaccination maximized HER-2-specific CD8+ T-cell immunity and tumor-free survival in neu transgenic mice. We therefore conducted a single arm feasibility study of CY, an allogeneic HER-2+ GM-CSF-secreting breast tumor vaccine, and weekly trastuzumab in 20 HER-2+ MBC patients. Primary clinical trial objectives were safety and clinical benefit (CB), in which CB represents complete response+partial response+stable disease. Secondary study objectives were to assess HER-2-specific T-cell responses by delayed type hypersensitivity (DTH) and intracellular cytokine staining. Subjects received three monthly vaccinations, with a boost 6-8 months from trial entry. This combination immunotherapy was safe, with CB rates at 6 months and 1 year of 55% (95% CI:32-77%, p=0.013) and 40% (95% CI:19-64%) respectively. Median progression-free survival (PFS) and overall survival (OS) were 7 (95% CI:4-16) and 42 months (95% CI:22-70) respectively. Increased HER-2-specific DTH developed in 7/20 subjects (of whom 4 had CB (95% CI:18-90)), with a trend toward longer PFS and OS in DTH responders. Polyfunctional HER-2-specific CD8+ T cells progressively expanded across vaccination cycles. Further investigation of CY-modulated vaccination with trastuzumab is warranted. (Clinicaltrials.gov identifier: NCT00399529)