A Phase Ib Trial of Personalized Neoantigen Therapy Plus Anti-PD-1 in Patients with Advanced Melanoma, Non-small Cell Lung Cancer, or Bladder Cancer.

Neoantigens arise from mutations in cancer cells and are important targets of T cell-mediated anti-tumor immunity. Here, we report the first open-label, phase Ib clinical trial of a personalized neoantigen-based vaccine, NEO-PV-01, in combination with PD-1 blockade in patients with advanced melanoma, non-small cell lung cancer, or bladder cancer. This analysis of 82 patients demonstrated that the regimen was safe, with no treatment-related serious adverse events observed. De novo neoantigen-specific CD4+ and CD8+ T cell responses were observed post-vaccination in all of the patients. The vaccine-induced T cells had a cytotoxic phenotype and were capable of trafficking to the tumor and mediating cell killing. In addition, epitope spread to neoantigens not included in the vaccine was detected post-vaccination. These data support the safety and immunogenicity of this regimen in patients with advanced solid tumors (Clinicaltrials.gov: NCT02897765).

BNT162b2 vaccine induces neutralizing antibodies and poly-specific T cells in humans.

BNT162b2, a nucleoside-modified mRNA formulated in lipid nanoparticles that encodes the SARS-CoV-2 spike glycoprotein (S) stabilized in its prefusion conformation, has demonstrated 95% efficacy in preventing COVID-191. Here we extend a previous phase-I/II trial report2 by presenting data on the immune response induced by BNT162b2 prime-boost vaccination from an additional phase-I/II trial in healthy adults (18-55 years old). BNT162b2 elicited strong antibody responses: at one week after the boost, SARS-CoV-2 serum geometric mean 50% neutralizing titres were up to 3.3-fold above those observed in samples from individuals who had recovered from COVID-19. Sera elicited by BNT162b2 neutralized 22 pseudoviruses bearing the S of different SARS-CoV-2 variants. Most participants had a strong response of IFNγ+ or IL-2+ CD8+ and CD4+ T helper type 1 cells, which was detectable throughout the full observation period of nine weeks following the boost. Using peptide-MHC multimer technology, we identified several BNT162b2-induced epitopes that were presented by frequent MHC alleles and conserved in mutant strains. One week after the boost, epitope-specific CD8+ T cells of the early-differentiated effector-memory phenotype comprised 0.02-2.92% of total circulating CD8+ T cells and were detectable (0.01-0.28%) eight weeks later. In summary, BNT162b2 elicits an adaptive humoral and poly-specific cellular immune response against epitopes that are conserved in a broad range of variants, at well-tolerated doses.

Personalized neoantigen vaccines: A new approach to cancer immunotherapy.

Neoantigens arise from somatic mutations that differ from wild-type antigens and are specific to each individual patient, which provide tumor specific targets for developing personalized cancer vaccines. Decades of work has increasingly shown the potential of targeting neoantigens to generate effective clinical responses. Current clinical trials using neoantigen targeting cancer vaccines, including in combination with checkpoint blockade monoclonal antibodies, have demonstrated potent T-cell responses against those neoantigens accompanied by antitumor effects in patients. Personalized neoantigen vaccines represent a potential new class of cancer immunotherapy.

A universal MHCII technology platform to characterize antigen-specific CD4+ T cells.

CD4+ T cells are critical to the immune system and perform multiple functions; therefore, their identification and characterization are crucial to better understanding the immune system in both health and disease states. However, current methods rarely preserve their ex vivo phenotype, thus limiting our understanding of their in vivo functions. Here we introduce a flexible, rapid, and robust platform for ex vivo CD4+ T cell identification. By combining MHCII allele purification, allele-independent peptide loading, and multiplexed flow cytometry technologies, we can enable high-throughput personalized CD4+ T cell identification, immunophenotyping, and sorting. Using this platform in combination with single-cell sorting and multimodal analyses, we identified and characterized antigen-specific CD4+ T cells relevant to COVID-19 and cancer neoantigen immunotherapy. Overall, our platform can be used to detect and characterize CD4+ T cells across multiple diseases, with potential to guide CD4+ T cell epitope design for any disease-specific immunization strategy.

Personalized neoantigen vaccine NEO-PV-01 with chemotherapy and anti-PD-1 as first-line treatment for non-squamous non-small cell lung cancer.

Neoantigens arising from mutations in tumor DNA provide targets for immune-based therapy. Here, we report the clinical and immune data from a Phase Ib clinical trial of a personalized neoantigen-vaccine NEO-PV-01 in combination with pemetrexed, carboplatin, and pembrolizumab as first-line therapy for advanced non-squamous non-small cell lung cancer (NSCLC). This analysis of 38 patients treated with the regimen demonstrated no treatment-related serious adverse events. Multiple parameters including baseline tumor immune infiltration and on-treatment circulating tumor DNA levels were highly correlated with clinical response. De novo neoantigen-specific CD4+ and CD8+ T cell responses were observed post-vaccination. Epitope spread to non-vaccinating neoantigens, including responses to KRAS G12C and G12V mutations, were detected post-vaccination. Neoantigen-specific CD4+ T cells generated post-vaccination revealed effector and cytotoxic phenotypes with increased CD4+ T cell infiltration in the post-vaccine tumor biopsy. Collectively, these data support the safety and immunogenicity of this regimen in advanced non-squamous NSCLC.

Efficacy of a dopamine-somatostatin chimeric molecule, BIM-23A760, in the control of cell growth from primary cultures of human non-functioning pituitary adenomas: a multi-center study.

Dopamine D2 and somatostatin receptors (sstrs) were reported to affect non-functioning pituitary adenoma (NFPA) proliferation in vitro. However, the reported results differ according to the experimental conditions used. We established an experimental protocol allowing reproducible evaluation of NFPA cell proliferation in vitro, to test and compare the antiproliferative effects of dopamine and somatostatin analogs (alone or in combination) with the activity of the dopamine-somatostatin chimeric molecule BIM-23A760. The protocol was utilized by four independent laboratories, studying 38 fibroblast-deprived NFPA cell cultures. Cells were characterized for GH, POMC, sstr1-sstr5, total dopamine D2 receptor (D2R) (in all cases), and D2 receptor long and short isoforms (in 15 out of 38 cases) mRNA expression and for alpha-subunit, LH, and FSH release. D2R, sstr3, and sstr2 mRNAs were consistently observed, with the dominant expression of D2R (2.9+/-2.6 copy/copy beta-glucuronidase; mean+/-s.e.m.), when compared with sstr3 and sstr2 (0.6+/-1.0 and 0.3+/-0.6 respectively). BIM-23A760, a molecule with high affinity for D2R and sstr2, significantly inhibited [3H]thymidine incorporation in 23 out of 38 (60%) NFPA cultures (EC50=1.2 pM and Emax=-33.6+/-3.7%). BIM-23A760 effects were similar to those induced by the selective D2R agonist cabergoline that showed a statistically significant inhibition in 18 out of 27 tumors (compared with a significant inhibition obtained in 17 out of 27 tumors using BIM-23A760, in the same subgroup of adenomas analyzed), while octreotide was effective in 13 out of 27 cases. In conclusion, superimposable data generated in four independent laboratories using a standardized protocol demonstrate that, in vitro, chimeric dopamine/sstr agonists are effective in inhibiting cell proliferation in two-thirds of NFPAs.

Ghrelin treatment of chronic kidney disease: improvements in lean body mass and cytokine profile.

Chronic kidney disease (CKD) is associated with an increase in inflammatory cytokines and can result in cachexia with loss of muscle and fat stores. We previously demonstrated the efficacy of treating a model of cancer cachexia with ghrelin and a ghrelin receptor agonist. Currently, we examine a surgical model of CKD in rats, resulting in uremia and decreased accrual of lean body mass. Treatment with ghrelin and two ghrelin receptor agonists (BIM-28125 and BIM-28131) resulted in increased food intake and an improvement in lean body mass accrual that was related in part to a decrease in muscle protein degradation as assessed by muscle levels of the 14-kDa actin fragment resulting from cleaved actomyosin. Additionally, there was a decrease in circulating inflammatory cytokines in nephrectomized animals treated with ghrelin relative to saline treatment. Ghrelin-treated animals also had a decrease in the expression of IL-1 receptor in the brainstem and a decrease in expression of prohormone convertase-2, an enzyme involved in the processing of proopiomelanocortin to the anorexigenic peptide alpha-MSH. We conclude that ghrelin treatment in uremia results in improved lean mass accrual in part due to suppressed muscle proteolysis and possibly related to antiinflammatory effects.

Bsx, a novel hypothalamic factor linking feeding with locomotor activity, is regulated by energy availability.

We recently reported that the hypothalamic homeobox domain transcription factor Bsx plays an essential role in the central nervous system control of spontaneous physical activity and the generation of hyperphagic responses. Moreover, we found Bsx to be a master regulator for the hypothalamic expression of key orexigenic neuropeptide Y and agouti gene-related protein. We now hypothesized that Bsx, which is expressed in the dorsomedial and arcuate nucleus (ARC) of the hypothalamus, is regulated by afferent signals in response to peripheral energy balance. Bsx expression was analyzed using in situ hybridization in fed vs. fasted (24 h) and ghrelin vs. leptin-treated rats, as well as in mice deficient for leptin or the ghrelin signaling. Ghrelin administration increased, whereas ghrelin receptor antagonist decreased ARC Bsx expression. Leptin injection attenuated the fasting-induced increase in ARC Bsx levels but had no effect in fed rats. Dorsomedial hypothalamic nucleus Bsx expression was unaffected by pharmacological modifications of leptin or ghrelin signaling. Obese leptin-deficient (ob/ob) mice, but not obese melanocortin 4 receptor-knockout mice, showed higher expression of Bsx, consistent with dependency from afferent leptin rather than increased adiposity per se. Interestingly, exposure to a high-fat diet triggered Bsx expression, consistent with the concept that decreased leptin signaling due to a high-fat diet induced leptin resistance. Our data indicate that ARC Bsx expression is specifically regulated by afferent energy balance signals, including input from leptin and ghrelin. Future studies will be necessary to test if Bsx may be involved in the pathogenesis of leptin resistance.

Regulation of growth hormone and prolactin gene expression and secretion by chimeric somatostatin-dopamine molecules.

Dopamine (DA) regulates both prolactin (PRL) secretion and gene expression, whereas somatostatin (SRIF) inhibits GH secretion with unclear effects on GH gene expression. We therefore tested the effects of SRIF analogs and chimeric SRIF/DA compounds BIM 23A760 and BIM 23A761 on GH and PRL secretion and gene expression in primary rat pituitary cultures and pituitary tumor GH(3) and MMQ cells. Chimeric SRIF/DA molecules suppressed GH release with a similar efficacy to SRIF receptor subtype 2 agonists in rat pituitary and GH(3) cells. After 24 h, BIM 23A760 and BIM 23A761 did not exert additive effects on GH secretion, and after 48 h were less effective than the combination of respective mono-receptor agonists in GH(3) cells. Real-time PCR did not reveal changes in GH mRNA levels after treatment with SRIF analogs and SRIF/DA molecules. SRIF/DA compounds suppressed PRL and PRL mRNA in rat pituitary and MMQ cells with a similar efficacy to D(2)-DA receptor agonist. In GH(3) cells, they suppressed PRL and PRL mRNA levels with a similar efficacy to SRIF receptor subtype 2 agonists. SRIF/DA molecules did not exhibit additive effects on PRL secretion and mRNA levels as compared with cotreatment with mono-receptor ligands. The results show that SRIF analogs and SRIF/DA molecules inhibit GH and PRL secretion and suppress PRL but not GH gene expression.

Ghrelin treatment causes increased food intake and retention of lean body mass in a rat model of cancer cachexia.

Cancer cachexia is a debilitating syndrome of anorexia and loss of lean body mass that accompanies many malignancies. Ghrelin is an orexigenic hormone with a short half-life that has been shown to improve food intake and weight gain in human and animal subjects with cancer cachexia. We used a rat model of cancer cachexia and administered human ghrelin and a synthetic ghrelin analog BIM-28131 via continuous infusion using sc osmotic minipumps. Tumor-implanted rats receiving human ghrelin or BIM-28131 exhibited a significant increase in food consumption and weight gain vs. saline-treated animals. We used dual-energy x-ray absorptiometry scans to show that the increased weight was due to maintenance of lean mass vs. a loss of lean mass in saline-treated animals. Also, BIM-28131 significantly limited the loss of fat mass normally observed in tumor-implanted rats. We further performed real-time PCR analysis of the hypothalami and brainstems and found that ghrelin-treated animals exhibited a significant increase in expression of orexigenic peptides agouti-related peptide and neuropeptide Y in the hypothalamus and a significant decrease in the expression of IL-1 receptor-I transcript in the hypothalamus and brainstem. We conclude that ghrelin and a synthetic ghrelin receptor agonist improve weight gain and lean body mass retention via effects involving orexigenic neuropeptides and antiinflammatory changes.

The toxicology of chemokine inhibition.

The dividing line between essential physiological inflammatory processes and excessive pathological inflammation is often very thin - in some circumstances, indeed, it may be non-existent. Devising anti-inflammatory medications that effectively target only the pathological component therefore remains a central challenge for the pharmaceutical industry. At present, the general rule is that the more powerful the anti-inflammatory effect of a drug, the greater the side-effects that accompany it. Steroids, for example, are potent anti-inflammatory medications, but they have a diverse array of side effects that substantially limit their use. Since chemokines play a central role in regulating the immune system, and in particular, the trafficking of leukocytes, inhibiting their action may represent a powerful new therapeutic strategy for treating diseases with an inflammatory component. However, this potential will only be realized if it is possible to interfere with chemokine signaling networks, without inducing unacceptable side effects. Although very little, direct human toxicology has been carried out using chemokine inhibitors, there is now a sufficient body of indirect and circumstantial evidence (for example, from genetically modified mice and from animal model studies using chemokine inhibitors) to allow a tentative assessment of the biological impact of chemokine inhibition. The purpose of this review is to outline the available data and to speculate on the likely toxicological profile resulting from chemokine inhibition. The tentative conclusion is that anti-inflammatory therapy achieved through chemokine inhibition may have fewer side effects than originally expected, even when the actions of multiple chemokines are inhibited simultaneously.

Functional association of somatostatin receptor subtypes 2 and 5 in inhibiting human growth hormone secretion.

We previously demonstrated that somatostatin (SRIF)-induced inhibition of GH secretion from human pituitary cells is mediated through both the SRIF receptor (SSTR) 2 and 5 subtypes. The interplay between these two SSTR subtypes in regulating GH was therefore tested in primary human fetal pituitary cultures (18-30 wk gestation). GHRH (10 nM)-stimulated GH secretion (51% increase, P < 0.05) was suppressed equally by either SSTR2 or SSTR5-selective agonists (10 nM). GH suppression correlated with agonist affinity for their respective receptor subtypes. Combined addition of SSTR2- and SSTR5-specific agonists was synergistic for GH suppression, achieving 73% (P < 0.05) inhibition as compared with inhibition attained with SSTR2 (32%) and SSTR5 (34%) agonists used alone (P < 0.05). The SSTR2 selective antagonist BIM-23454 dose-dependently blocked SSTR2 but not SSTR5-induced suppression of GH secretion. BIM-23454 also completely reversed GH suppression in response to the combined activation of SSTR2 and SSTR5. The IC(50) for BIM-23454 reversal of agonist-induced GH suppression was 55 nM and 33 nM for two SSTR2 agonists, 45 nM and 40 nM for the combination of SSTR2 and SSTR5 agonists, respectively, and 45 nM for the SSTR2/SSTR5 agonist BIM-23244, all of which were similar to the affinity of BIM-23454 for SSTR2 (32 nM). These results suggest the following: 1) activation of both SSTR2 and SSTR5 induces a functional association of receptor subtypes, resulting in synergistic GH suppression; 2) BIM-23454 is a potent SSTR2-selective antagonist capable of reversing SRIF-induced GH suppression; and 3) the ability of a selective SSTR2 antagonist to inhibit the GH suppressing action of SSTR2 agonist alone, SSTR2/SSTR5 biselective agonists, or SSTR2 and SSTR5 agonists in combination support the concept of a functional interaction between somatotroph SSTR2 and SSTR5 subtypes in primary human fetal pituitary cells.

Novel analogs of ghrelin: physiological and clinical implications.

Ghrelin, the 28 amino acid peptide recently identified as the natural ligand for the growth hormone (GH) secretagogue (GHS) receptor, has multiple activities in addition to stimulation of GH secretion, including stimulation of feeding and weight gain. To utilize these actions for potential therapeutic benefit, we have produced analogs of human ghrelin with enhanced metabolic stability, affinity for the GHS receptor, and efficacy in stimulating weight gain. We have also discovered an analog of ghrelin, BIM-28163, that is an antagonist at the GHS receptor and that fully inhibits GHS receptor activation induced by native ghrelin. In vivo, BIM-28163 does not increase GH secretion but fully blocks ghrelin-induced GH secretion. In contrast, BIM-28163 acts as a full agonist with regard to the ghrelin actions of stimulating weight gain and food intake. These results suggest that a receptor other than the GHS receptor mediates the actions of ghrelin on feeding and weight gain. This concept is strengthened by our observation that at certain hypothalamic sites, BIM-28163 acts as an antagonist of ghrelin-induced neuronal activation, while at other sites, both ghrelin and BIM-28163 induce neuronal activation via the same receptor. Collectively, these results indicate the existence of a novel ghrelin receptor that may regulate the feeding activity of ghrelin. Using BIM-28163 as a tool to define the endogenous role of ghrelin in normal GH secretion, we have demonstrated that antagonism of the GHS receptor in normal rats does not impair the pulsatility of GH secretion but lowers the pulse amplitude and mean GH level. These results demonstrate that endogenous ghrelin acts to amplify the basic pattern of GH secretion established by the interplay of hypothalamic GH-releasing hormone and somatostatin. These studies demonstrate the feasibility of creating ghrelin analogs that are selective for specific activities, as well as their utility in dissecting the role of ghrelin in both normal physiology and specific pathologies.

Targeted delivery to cartilage is critical for in vivo efficacy of insulin-like growth factor 1 in a rat model of osteoarthritis.

OBJECTIVE: Acute articular injuries lead to an increased risk of progressive joint damage and osteoarthritis (OA), and no therapies are currently available to repair or protect the injured joint tissue. Intraarticular delivery of therapeutic proteins has been limited by their rapid clearance from the joint space and lack of retention within cartilage. The aim of this study was to test whether targeted delivery to cartilage by fusion with a heparin-binding domain would be sufficient to prolong the in vivo function of the insulin-like growth factor 1 (IGF-1). METHODS: We produced a humanized and optimized recombinant HB-IGF-1 fusion protein. By injecting HB-IGF-1, IGF-1, or saline alone into the knee joints of adult Lewis rats, we tested whether fusion with a heparin-binding domain 1) altered the kinetics of retention in joint tissues, 2) prolonged functional stimulation as measured by radiolabel incorporation, and 3) enhanced efficacy in a rat model of surgically induced OA, using weekly injections. RESULTS: Fusion of heparin-binding domain with IGF-1 prolonged retention in articular and meniscal cartilage from <1 day to 8 days after injection. Unmodified IGF-1 had no functional effect 2 days after injection, whereas HB-IGF-1 stimulated meniscal cartilage at least 4 days after injection. HB-IGF-1, but not IGF-1, significantly slowed cartilage damage in a rat model of OA. CONCLUSION: Heparin-binding domain fusions can transform rapidly cleared proteins into potential intraarticular therapies by targeting them to cartilage.

Preclinical gastrointestinal prokinetic efficacy and endocrine effects of the ghrelin mimetic RM-131.

AIMS: The 28 amino acid hormone ghrelin, the natural ligand for the growth hormone secretagogue, or ghrelin receptor (GHR), has diverse physiological functions, including a possible role as a gastrointestinal prokinetic. The synthetic ghrelin mimetic RM-131 is in Phase II clinical trials for treatment of diabetic gastroparesis and other gastrointestinal (GI) disorders. We aimed to determine the relative potency of RM-131, when compared to other GI ghrelin mimetics, to predict efficacy and determine the role of RM-131 in models of inflammatory bowel disease. MAIN METHODS: We evaluated and compared ghrelin, RM-131 and other synthetic ghrelin mimetics for their prokinetic potency in models of gastrointestinal disorders in the rat and we evaluated the endocrine (rats and dogs) and anti-inflammatory effects (mice) of the ghrelin mimetic RM-131. KEY FINDINGS: The pentapeptide RM-131 increased gastric emptying in rodent models of ileus. RM-131 is about 100-fold more potent than human ghrelin and is 600 to 1800-fold more potent, when compared to several investigational ghrelin mimetics tested in clinical trials. RM-131 has anti-inflammatory effects and significantly increases survival and reduces macroscopic markers of tissue damage in a TNBS model of inflammatory bowel disease. RM-131 treatment shows a transient increase in growth hormone levels in Beagle dogs and rats, returning to baseline upon chronic treatment. Significant effects on glucose and insulin are not observed in chronic studies. SIGNIFICANCE: RM-131's potency, efficacy and endocrine profile, are promising attributes for the treatment of diverse functional gastrointestinal disorders in humans.

Effect of application route of the ghrelin analog BIM-28131 (RM-131) on body weight and body composition in a rat heart failure model.

Chronic heart failure (CHF) remains one of the most challenging diseases in terms of numbers and disease management, particularly so, if the CHF patient develops cardiac cachexia. Ghrelin and its analogs have been suggested to improve body weight and cardiac function in heart failure models and exploratory human clinical studies. However, most ghrelin compounds are peptides and need to be injected several times per day, which affects the quality of life of patients. Here, we compared two application routes, three times daily subcutaneous (sc) injections to continuous infusion using osmotic mini-pumps in a rat model of CHF. Moreover, the effects were also compared to three times daily sc injections of growth hormone (GH). Rats were treated for 28 d. The results show that treatment with 50 or 100 nmol/kg/d BIM-28131 (RM-131) potently induces body weight gain, fat and lean mass compared to placebo. The gain of lean mass was equal to the gain of lean mass in the 2mg/kg/d GH group and superior to 250 µg/kg/d GH. Both GH and BIM-28131 increased levels of insulin-like growth factor-1 to a similar extent. Little effect was seen on cardiac function; only cardiac output was improved by either high dose BIM-28131 or GH. Overall the effects of BIM-28131 were similar in both application routes.

Effect of ghrelin and its analogues, BIM-28131 and BIM-28125, on the expression of myostatin in a rat heart failure model.

BACKGROUND: In chronic heart failure (CHF), cachexia is a hallmark of the terminal stage of this disease and is associated with a severely reduced quality of life and poor prognosis. Therapeutic options are currently not available. Ghrelin and its analogues BIM-28125 and BIM-28131 (now known as RM-131) have been shown to increase weight in a rat model of CHF. It has been further demonstrated that the expression of myostatin, a negative regulator of skeletal muscle mass, is increased in CHF. The aim of the study was to investigate the influence of ghrelin or its analogues on myostatin in CHF. METHODS: In an animal model of CHF, Sprague-Dawley rats received either ghrelin or two ghrelin analogues BIM-28125 and BIM-28131 in two different concentrations (50 and 500 nmol/kg/day) compared to placebo. The compounds were delivered using osmotic mini pumps. The expression of myostatin was analyzed in skeletal muscle by RT-PCR and Western blot, and muscle mass of gastrocnemius muscle was measured. The plasma levels of tumor necrosis factor alpha (TNF-α) were measured. RESULTS: The relative weight of the gastrocnemius muscle of the sham-operated group was significantly increased compared to placebo-treated CHF rats. The application of ghrelin analogue BIM-28125 and BIM-28131 in their higher concentrations led to a significant reduction in myostatin mRNA expression in comparison to placebo. Myostatin protein expression was significantly reduced in both concentrations of ghrelin and BIM-28131 and in the lower concentration of BIM-28125. The increase of TNF-α plasma concentration in the CHF-animals could be abolished by all used substances. CONCLUSIONS: In an animal model of CHF, the expression of myostatin is significantly reduced in the skeletal muscle after application of ghrelin and most concentrations of its analogues BIM-28125 and BIM-28131 possibly due to anti-inflammatory effects.

Chronic treatment with a melanocortin-4 receptor agonist causes weight loss, reduces insulin resistance, and improves cardiovascular function in diet-induced obese rhesus macaques.

The melanocortin-4 receptor (MC4R) is well recognized as an important mediator of body weight homeostasis. Activation of MC4R causes dramatic weight loss in rodent models, and mutations in human are associated with obesity. This makes MC4R a logical target for pharmacological therapy for the treatment of obesity. However, previous studies in rodents and humans have observed a broad array of side effects caused by acute treatment with MC4R agonists, including increased heart rate and blood pressure. We demonstrate that treatment with a highly-selective novel MC4R agonist (BIM-22493 or RM-493) resulted in transient decreases in food intake (35%), with persistent weight loss over 8 weeks of treatment (13.5%) in a diet-induced obese nonhuman primate model. Consistent with weight loss, these animals significantly decreased adiposity and improved glucose tolerance. Importantly, we observed no increases in blood pressure or heart rate with BIM-22493 treatment. In contrast, treatment with LY2112688, an MC4R agonist previously shown to increase blood pressure and heart rate in humans, caused increases in blood pressure and heart rate, while modestly decreasing food intake. These studies demonstrate that distinct melanocortin peptide drugs can have widely different efficacies and side effects.