Preclinical, randomized phase 1, and compassionate use evaluation of REGN4461, a leptin receptor agonist antibody for leptin deficiency.

Deficiency in the adipose-derived hormone leptin or leptin receptor signaling causes class 3 obesity in individuals with genetic loss-of-function mutations in leptin or its receptor LEPR and metabolic and liver disease in individuals with hypoleptinemia secondary to lipoatrophy such as in individuals with generalized lipodystrophy. Therapies that restore leptin-LEPR signaling may resolve these metabolic sequelae. We developed a fully human monoclonal antibody (mAb), REGN4461 (mibavademab), that activates the human LEPR in the absence or presence of leptin. In obese leptin knockout mice, REGN4461 normalized body weight, food intake, blood glucose, and insulin sensitivity. In a mouse model of generalized lipodystrophy, REGN4461 alleviated hyperphagia, hyperglycemia, insulin resistance, dyslipidemia, and hepatic steatosis. In a phase 1, randomized, double-blind, placebo-controlled two-part study, REGN4461 was well tolerated with an acceptable safety profile. Treatment of individuals with overweight or obesity with REGN4461 decreased body weight over 12 weeks in those with low circulating leptin concentrations (<8 ng/ml) but had no effect on body weight in individuals with higher baseline leptin. Furthermore, compassionate-use treatment of a single patient with atypical partial lipodystrophy and a history of undetectable leptin concentrations associated with neutralizing antibodies to metreleptin was associated with noteable improvements in circulating triglycerides and hepatic steatosis. Collectively, these translational data unveil an agonist LEPR mAb that may provide clinical benefit in disorders associated with relatively low leptin concentrations.

Cardiac phenotype in familial partial lipodystrophy.

OBJECTIVES: LMNA variants have been previously associated with cardiac abnormalities independent of lipodystrophy. We aimed to assess cardiac impact of familial partial lipodystrophy (FPLD) to understand the role of laminopathy in cardiac manifestations. STUDY DESIGN: Retrospective cohort study. METHODS: Clinical data from 122 patients (age range: 13-77, 101 females) with FPLD were analysed. Mature human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a patient with an LMNA variant were studied as proof-of-concept for future studies. RESULTS: Subjects with LMNA variants had a higher prevalence of overall cardiac events than others. The likelihood of having an arrhythmia was significantly higher in patients with LMNA variants (OR: 3.77, 95% CI: 1.45-9.83). These patients were at higher risk for atrial fibrillation or flutter (OR: 5.78, 95% CI: 1.04-32.16). The time to the first arrhythmia was significantly shorter in the LMNA group, with a higher HR of 3.52 (95% CI: 1.34-9.27). Non-codon 482 LMNA variants were more likely to be associated with cardiac events (vs. 482 LMNA: OR: 4.74, 95% CI: 1.41-15.98 for arrhythmia; OR: 17.67, 95% CI: 2.45-127.68 for atrial fibrillation or flutter; OR: 5.71, 95% CI: 1.37-23.76 for conduction disease). LMNA mutant hiPSC-CMs showed a higher frequency of spontaneous activity and shorter action potential duration. Functional syncytia of hiPSC-CMs displayed several rhythm alterations such as early afterdepolarizations, spontaneous quiescence and spontaneous tachyarrhythmia, and significantly slower recovery in chronotropic changes induced by isoproterenol exposure. CONCLUSIONS: Our results highlight the need for vigilant cardiac monitoring in FPLD, especially in patients with LMNA variants who have an increased risk of developing cardiac arrhythmias. In addition, hiPSC-CMs can be studied to understand the basic mechanisms for the arrhythmias in patients with lipodystrophy to understand the impact of specific mutations.

Metreleptin therapy for nonalcoholic steatohepatitis: Open-label therapy interventions in two different clinical settings.

BACKGROUND: Recombinant leptin therapy reverses nonalcoholic steatohepatitis (NASH) in leptin-deficient lipodystrophy. We inquired if leptin therapy would improve nonalcoholic steatohepatitis in more common forms of this heterogeneous condition. METHODS: Nine male patients with relative leptin deficiency (level < 25th percentile of body mass index- and gender-matched United States population) and biopsy-proven NASH and 23 patients with partial lipodystrophy and NASH were recruited for two distinctive open-label trials. Participants received leptin therapy in the form of metreleptin for 12 months. The primary endpoints were the global nonalcoholic steatohepatitis scores from paired liver biopsies scored blindly. FINDINGS: Of 9 participants recruited in the relative leptin deficiency treatment study, 7 completed 12-months of therapy. Mean global NASH scores were reduced from 8 ± 3 to 5 ± 2 (range: from 1 to 6, P = 0.004). In the partial lipodystrophy study, 19 of 22 subjects completed 12 months of treatment, and 18 completed a second liver biopsy. Global NASH scores also reduced significantly from 6 ± 2 to 5 ± 2 (range: from -2 to 4, P = 0.008). In both studies, the predominant changes were in steatosis and hepatic injury scores. CONCLUSION: Our findings show that patients with NASH associated with both relative leptin deficiency and partial lipodystrophy have reductions in hepatic steatosis and injury in response to exogenous leptin therapy. Moreover, leptin deficiency may have regulatory effects in mediating fat deposition and ensuing injury in the liver.TRIAL REGISTRATION. ClinicalTrials.gov NCT00596934 and NCT01679197.

The complicated clinical course in a case of atypical lipodystrophy after development of neutralizing antibody to metreleptin: treatment with setmelanotide.

SUMMARY: A patient with atypical partial lipodystrophy who had a transient initial response to metreleptin experienced acute worsening of her metabolic state when neutralizing antibodies against metreleptin appeared. Because her metabolic status continued to deteriorate, a therapeutic trial with melanocortin-4 receptor agonist setmelanotide, that is believed to function downstream from leptin receptor in the leptin signaling system, was undertaken in an effort to improve her metabolic status for the first time in a patient with lipodystrophy. To achieve this, a compassionate use (investigational new drug application; IND) was initiated (NCT03262610). Glucose control, body fat by dual-energy X-ray absorptiometry and MRI, and liver fat by proton density fat fraction were monitored. Daily hunger scores were assessed by patient filled questionnaires. Although there was a slight decrease in hunger scales and visceral fat, stimulating melanocortin-4 receptor by setmelanotide did not result in any other metabolic benefit such as improvement of hypertriglyceridemia or diabetes control as desired. Targeting melanocortin-4 receptor to regulate energy metabolism in this setting was not sufficient to obtain a significant metabolic benefit. However, complex features of our case make it difficult to generalize these observations to all cases of lipodystrophy. It is still possible that melanocortin-4 receptor agonistic action may offer some therapeutic benefits in leptin-deficient patients. LEARNING POINTS: A patient with atypical lipodystrophy with an initial benefit with metreleptin therapy developed neutralizing antibodies to metreleptin (Nab-leptin), which led to substantial worsening in metabolic control. The neutralizing activity in her serum persisted for longer than 3 years. Whether the worsening in her metabolic state was truly caused by the development of Nab-leptin cannot be fully ascertained, but there was a temporal relationship. The experience noted in our patient at least raises the possibility for concern for substantial metabolic worsening upon emergence and persistence of Nab-leptin. Further studies of cases where Nab-leptin is detected and better assay systems to detect and characterize Nab-leptin are needed. The use of setmelanotide, a selective MC4R agonist targeting specific neurons downstream from the leptin receptor activation, was not effective in restoring metabolic control in this complex patient with presumed diminished leptin action due to Nab-leptin. Although stimulating the MC4R pathway was not sufficient to obtain a significant metabolic benefit in lowering triglycerides and helping with her insulin resistance as was noted with metreleptin earlier, there was a mild reduction in reported food intake and appetite. Complex features of our case make it difficult to generalize our observation to all leptin-deficient patients. It is possible that some leptin-deficient patients (especially those who need primarily control of food intake) may still theoretically benefit from MC4R agonistic action, and further studies in carefully selected patients may help to tease out the differential pathways of metabolic regulation by the complex network of leptin signaling system.

Diagnosis of acquired generalized lipodystrophy in a single patient with T-cell lymphoma and no exposure to Metreleptin.

BACKGROUND: Metreleptin, a recombinant methionyl -human -leptin, was approved to treat patients with generalized lipodystrophy (GL) in February 2014. However, leptin therapy has been associated with the development of lymphoma. We present a unique case of a patient with prior history of T cell lymphoma in remission, who was diagnosed with Acquired Generalized Lipodystrophy (AGL) during the following year after a clinical remission of her lymphoma without receiving leptin therapy. CASE PRESENTATION: A 33-year-old woman with a diagnosis of stage IV subcutaneous panniculitis like T-cell lymphoma in 2011, underwent chemotherapy. Shortly after completion therapy, she had a relapse and required more chemotherapy with complete response, followed by allogenic stem cell transplant on June 28, 2012. Since that time, she has been on observation with no evidence of disease recurrence. Subsequent to the treatment, she was found to have high triglycerides, loss of fat tissue from her entire body and diagnosis of diabetes. Constellation of these findings led to the diagnosis of AGL in 2013. Her leptin level was low at 3.4 ng/mL (182 pmol/mL). She is currently not receiving any treatment with Metreleptin for her AGL. CONCLUSIONS: Causal association between exogenous leptin therapy and T-cell lymphoma still remains unclear. We hereby present a case of a young woman who was diagnosed with AGL after going into remission from T-cell lymphoma and who has never been treated with Metreleptin. Steroid therapy and chemotherapy might have masked the diagnosis of AGL in this patient. We believe that patients can develop these 2 conditions independent of each other.

Inhibition of IKKɛ and TBK1 Improves Glucose Control in a Subset of Patients with Type 2 Diabetes.

Numerous studies indicate an inflammatory link between obesity and type 2 diabetes. The inflammatory kinases IKKɛ and TBK1 are elevated in obesity; their inhibition in obese mice reduces weight, insulin resistance, fatty liver and inflammation. Here we studied amlexanox, an inhibitor of IKKɛ and TBK1, in a proof-of-concept randomized, double-blind, placebo-controlled study of 42 obese patients with type 2 diabetes and nonalcoholic fatty liver disease. Treatment of patients with amlexanox produced a statistically significant reduction in Hemoglobin A1c and fructosamine. Interestingly, a subset of drug responders also exhibited improvements in insulin sensitivity and hepatic steatosis. This subgroup was characterized by a distinct inflammatory gene expression signature from biopsied subcutaneous fat at baseline. They also exhibited a unique pattern of gene expression changes in response to amlexanox, consistent with increased energy expenditure. Together, these data suggest that dual-specificity inhibitors of IKKɛ and TBK1 may be effective therapies for metabolic disease in an identifiable subset of patients.

The peroxisome proliferator activated receptor-γ pioglitazone improves vascular function and decreases disease activity in patients with rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is associated with heightened mortality due to atherosclerotic cardiovascular disease (CVD). Inflammatory pathways in RA negatively affect vascular physiology and promote metabolic disturbances that contribute to CVD. We hypothesized that the peroxisome proliferator activated receptor-γ (PPAR-γ) pioglitazone could promote potent vasculoprotective and anti-inflammatory effects in RA. METHODS AND RESULTS: One hundred forty-three non-diabetic adult RA patients (76.2% female, age 55.2 ± 12.1 [mean ± SD]) on stable RA standard of care treatment were enrolled in a randomized, double-blind placebo controlled crossover trial of 45 mg daily pioglitazone versus placebo, with a 3-month duration/arm and a 2-month washout period. Pulse wave velocity of the aorta (PWV), brachial artery flow mediated dilatation (FMD), nitroglycerin mediated dilatation (NMD), microvascular endothelial function (reactive hyperemia index [RHI]), and circulating biomarkers of inflammation, insulin resistance, and atherosclerosis risk all were quantified. RA disease activity was assessed with the 28-Joint Count Disease Activity Score (DAS-28) C-reactive protein (CRP) and the Short Form (36) Health Survey quality of life questionnaire. When added to standard of care RA treatment, pioglitazone significantly decreased pulse wave velocity (ie, aortic stiffness) (P=0.01), while FMD and RHI remained unchanged when compared to treatment with placebo. Further, pioglitazone significantly reduced RA disease activity (P=0.02) and CRP levels (P=0.001), while improving lipid profiles. The drug was well tolerated. CONCLUSIONS: Addition of pioglitazone to RA standard of care significantly improves aortic elasticity and decreases inflammation and disease activity with minimal safety issues. The clinical implications of these findings remain to be established. CLINICAL TRIAL REGISTRATION URL: ClinicalTrials.gov Unique Identifier: NCT00554853.

Interleukin 17 as a novel predictor of vascular function in rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is associated with enhanced cardiovascular (CV) risk and subclinical vascular disease. The proinflammatory milieu has been linked to premature atherosclerosis and endothelial dysfunction in RA. While interleukin 17 (IL-17) is considered pathogenic in RA, its role in determining vascular dysfunction in this disease has not been systematically assessed. OBJECTIVES: To analyse candidate variables that might determine endothelial function in various vascular territories in a cohort of patients with RA receiving treatment with biological agents, with minimal traditional CV risk factors and low disease activity score. METHODS: Patients with RA (n=50) receiving stable treatment with biological agents underwent measurement of conduit artery endothelial function by brachial artery flow-mediated dilatation; arterial compliance by pulse wave velocity (PWV) assessment; and endothelium-dependent microvascular testing with Endo-Pat2000 device to assess the reactive hyperaemia index (RHI). IL-17 was quantified by ELISA and disease activity was assessed by 28-joint count Disease Activity Score. RESULTS: IL-17 was the main determinant of lower RHI in univariate and multivariate analysis. Traditional and non-traditional CV risk variables determined PWV, with a significant positive association with IL-17 in univariate and multivariate analysis. In contrast, conduit endothelial function was mainly determined by rheumatoid factor titres in univariate and multivariate analysis. Anti-cyclic citrullinated peptide titres, specific disease-modifying antirheumatic drugs or biological agents and disease activity did not determine vascular function. CONCLUSION: In patients with RA treated with biological agents, IL-17 is a main predictor of microvascular function and arterial compliance. This study suggests that IL-17 may play a significant role in development of endothelial dysfunction and cardiovascular disease in RA.

Determinants of vascular function in patients with chronic gout.

Epidemiologic studies have proposed a relationship between hyperuricemia and cardiovascular (CV) risk. However, it is unclear whether uric acid (UA) is an independent risk factor for CV disease (CVD) after controlling for other predisposing conditions. Gout patients might have persistent systemic inflammation, which, in addition to hyperuricemia, may potentiate CVD. This study examined vascular function and markers of CV damage in gout patients when compared with healthy controls. Brachial artery flow-mediated dilatation, arterial compliance, and microvascular function were measured. Circulating apoptotic endothelial cells and endothelial progenitor cells were quantified by FACS and circulating biomarkers of CVD by enzyme-linked immunosorbent assay. Gout patients displayed significant increases in body mass index, C-reactive protein, UA, and triglycerides and decreases in high-density lipoprotein. There were no significant differences in other CV traditional risk factors, adhesion molecules, or chemokines. Gout patients did not differ from controls in vascular function. In univariate and multivariate analysis, UA was not associated with the quantified CV risk parameters. Despite an increase in several CV risk factors, inflammation, and UA, gout patients display normal endothelial function and no increases in biomarkers of CVD. These results do not support the notion that gout is an independent risk factor for premature CVD.