Claire Higham

Association between hepatic steatosis and serum IGF1 and IGFBP-3 levels in a population-based sample

CONTEXT It is assumed that hepatic steatosis plays a role in the development and progression of the metabolic syndrome and its cardiovascular sequelae. Low serum IGF1 levels might mediate these associations. OBJECTIVES The aims of this study were i) to investigate the associations of hepatic steatosis with serum IGF1 and IGF binding protein-3 (IGFBP-3) levels using ultrasound and serum alanine aminotransaminase (ALT) data to define hepatic steatosis, and ii) to analyze the specific role of alcohol consumption in this context. DESIGN We analyzed data from the population-based Study of Health in Pomerania. METHODS We used data from 3863 subjects (1971 women) aged 20-79 years who had no history of viral hepatitis, liver cirrhosis, or malignant diseases. Liver hyperechogenicity was diagnosed using ultrasound. Serum IGF1 and IGFBP-3 levels were determined by automated two-site chemiluminescence immunoassays. RESULTS Hyperechogenic liver pattern was associated with low serum IGF1 levels and low serum IGF1/IGFBP-3 ratios. The lowest serum IGF1 and IGF1/IGFBP-3 values and highest IGFBP-3 levels were present in subjects who had a hyperechogenic liver pattern and increased serum ALT levels. All of these associations were independent of alcohol consumption. CONCLUSIONS Our data show that hepatic steatosis is associated with low serum IGF1 levels. This association is independent of alcohol consumption.

Effective Combination Treatment with Cabergoline and Low-Dose Pegvisomant in Active Acromegaly: A Prospective Clinical Trial

CONTEXT With adequate dose titration, pegvisomant normalizes IGF-I in up to 97% of patients with acromegaly. Pegvisomant is indicated for treatment-resistant disease but is expensive, particularly at a high dose. It has been used successfully in combination with somatostatin analogs. However, there are no therapeutic reports of pegvisomant in combination with dopamine agonists. Cabergoline is orally active, well-tolerated, and relatively inexpensive, and as monotherapy for acromegaly it is reported to normalize IGF-I in up to 30% of patients. OBJECTIVE The aim of the study was to investigate the efficacy of cabergoline monotherapy and pegvisomant in combination with cabergoline to control serum IGF-I in patients with active acromegaly. Twenty-four patients were recruited into a United Kingdom, multicenter, open-label, prospective clinical trial. MAIN OUTCOME MEASURE We measured the change in serum IGF-I. RESULTS After 18 wk of dose titration to a maximum dose of 0.5 mg once daily, cabergoline monotherapy did not significantly reduce IGF-I (454 ± 219 baseline vs. 389 ± 192 ng/ml cabergoline), although two patients did normalize IGF-I. The addition of 10 mg pegvisomant daily for 12 wk significantly reduced IGF-I (389 ± 192 ng/ml cabergoline vs. 229 ± 101 ng/ml combination), and 68% achieved a normal IGF-I. Twelve weeks after cabergoline withdrawal, while continuing to receive pegvisomant 10 mg, only 26% of patients maintained an IGF-I within the reference range (229 ± 101 ng/ml combination vs. 305 ± 177 ng/ml pegvisomant). There were no significant changes in liver transaminases or glucose metabolism throughout the study. CONCLUSION These data suggest that combination treatment with cabergoline and pegvisomant is more effective at reducing IGF-I levels than either cabergoline or pegvisomant monotherapy.

Long-term experience of pegvisomant therapy as a treatment for acromegaly.

Aims  To evaluate the long‐term efficacy and safety of pegvisomant as a treatment for acromegaly.

GH safety workshop position paper: a critical appraisal of recombinant human GH therapy in children and adults.

Recombinant human GH (rhGH) has been in use for 30 years, and over that time its safety and efficacy in children and adults has been subject to considerable scrutiny. In 2001, a statement from the GH Research Society (GRS) concluded that ‘for approved indications, GH is safe’; however, the statement highlighted a number of areas for on-going surveillance of long-term safety, including cancer risk, impact on glucose homeostasis, and use of high dose pharmacological rhGH treatment. Over the intervening years, there have been a number of publications addressing the safety of rhGH with regard to mortality, cancer and cardiovascular risk, and the need for long-term surveillance of the increasing number of adults who were treated with rhGH in childhood. Against this backdrop of interest in safety, the European Society of Paediatric Endocrinology (ESPE), the GRS, and the Pediatric Endocrine Society (PES) convened a meeting to reappraise the safety of rhGH. The ouput of the meeting is a concise position statement.

Pegvisomant improves insulin sensitivity and reduces overnight free fatty acid concentrations in patients with acromegaly.

INTRODUCTION Acromegaly is complicated by an increased incidence of diabetes mellitus caused by impaired insulin sensitivity and reduced beta-cell function. Pegvisomant blocks activity at GH receptors, normalizing IGF-I in over 90% of patients and improving insulin sensitivity. The mechanisms for this increase in insulin sensitivity are not fully determined. We used stable isotope techniques to investigate the effects of pegvisomant on glucose and lipid metabolism in acromegaly. METHODS Five patients (age, 43 yr +/- sd) with active acromegaly were studied on two occasions: before pegvisomant and after 4 wk of pegvisomant (20 mg daily sc). (2)H(5)-glycerol was infused overnight to measure overnight and early morning (basal) glycerol production rate (Ra). The next morning (2)H(2)-glucose was infused for 2 h before and throughout a hyperinsulinemic euglycemic (1.5 mU/kg x min insulin) clamp to measure basal glucose Ra and insulin-stimulated peripheral glucose disposal (Rd). RESULTS Mean IGF-I was significantly reduced after pegvisomant treatment (mean, 539 +/- 176 vs. 198 +/- 168 microg/ml; P = 0.001). The insulin sensitivity of endogenous glucose production was significantly increased after pegvisomant [mean glucose Ra *insulin, 118.5 +/- 28 vs. 69.2 +/- 22 micromol/kg x min *(mU/liter); P = 0.04]. No differences in glucose Rd were seen after pegvisomant. All patients showed a reduction in glycerol Ra adjusted for insulin [mean, 18.12 +/- 1.75 vs. 14.4 +/- 4.75 micromol/kg x min *(mU/liter); P = 0.08] and overnight FFA concentrations (mean area under the curve, 278 +/- 84 vs. 203 +/- 71; P < 0.05) after pegvisomant. CONCLUSION Short-term administration of pegvisomant leads to a reduction in overnight endogenous glucose production, and this may be related to reduced levels of FFA.

Growth hormone excess and the development of growth hormone receptor antagonists

In 1990, a single amino acid substitution in the growth hormone (GH) gene at position 119 was found to transform the consequent protein from an agonist to an antagonist at the growth hormone receptor (GHR). Further amino acid substitutions plus prolongation of the half‐life of the protein by pegylation resulted in the first clinically effective GHR antagonist, pegvisomant. Following extensive clinical trials, this medication has emerged as the most efficacious therapy for treatment‐resistant acromegaly. Subsequent advances in our understanding of GH–GHR interactions and downstream GH signalling pathways suggest that pegvisomant binds to preformed GHR dimers and prevents rotational changes within the receptor–GH complex necessary for intracellular signalling to occur. This article reviews the discovery of pegvisomant, from initial experimental data to successful licensing of the drug for treatment‐resistant acromegaly, and discusses its other potential therapeutic uses in diseases with abnormalities in the GH–IGF‐I axis.

Acromegaly surgery in Manchester revisited - The impact of reducing surgeon numbers and the 2010 consensus guidelines for disease remission.

Introduction  Surgical remission rates for acromegaly vary and are dependent on the tumour morphology, biochemical definition of disease remission and surgical expertise. A previous report from the Manchester region in 1998 reported an overall surgical remission rate of 27% using accepted criteria for biochemical remission at the time. The establishment of the 2010 Consensus guidelines further tightens biochemical criteria for remission. This report aims to assess the impact of establishing a specialist pituitary surgery service in Manchester in 2005, with reduced surgeon numbers on the remission rates for acromegaly surgery.

Successful use of weekly pegvisomant administration in patients with acromegaly

CONTEXT Clinical trials using 80 mg once weekly pegvisomant (pegV) in active acromegaly led to a 30% fall in serum IGF1. Subsequent studies demonstrated that daily administration of up to 40 mg/day achieved an IGF1 within reference range in 97% of patients. PegV has a half-life of >70 h suggesting weekly dosing may be possible but using higher doses than in the initial trials. OBJECTIVE To determine the efficacy of weekly dosing of pegV. DESIGN A two center, open-label prospective study in patients with acromegaly converted from a stable daily dose of pegV (median dose 15 mg daily (range 10-20 mg od), IGF1 normal for 3 months prior to inclusion) to twice-weekly (week 0-16) followed by once-weekly (week 16-32) administration. RESULTS Seven patients (4M, age 57+/-7 years, 6/7 prior transsphenoidal surgery, 7/7 prior radiotherapy) were recruited. Six patients completed the twice-weekly and five patients both the twice-weekly and once-weekly administration. Headaches led to two patient withdrawals at 0+24 weeks. Mean pre-dose serum IGF1 levels remained stable with the different administration regimens (IGF1 baseline 145+/-39 ng/ml, twice-weekly 124+/-39 ng/ml and once-weekly 127+/-22 ng/ml) and all values were within age adjusted IGF1 reference range. PegV dose was reduced in two patients and five opted to continue weekly administration at trial termination. Safety and quality of life parameters remained stable. CONCLUSIONS Twice and once-weekly administration of pegV is effective in controlling serum IGF1 levels in acromegaly and although not formally assessed, continuation of weekly dosing in five patients at study conclusion suggests patient preference for this regimen.

Hyponatraemia secondary to nivolumab-induced primary adrenal failure.

Summary Checkpoint inhibitors, such as ipilimumab and pembrolizumab, have transformed the prognosis for patients with advanced malignant melanoma and squamous non-small-cell lung cancer, and their use will only expand as experience is gained in a variety of other malignancies, for instance, renal and lymphoma. As the use of checkpoint inhibitors increases, so too will the incidence of their unique side effects, termed immune-related adverse events (irAEs), which can affect dermatological, gastrointestinal, hepatic, endocrine and other systems. Nivolumab is a monoclonal antibody that blocks the human programmed death receptor-1 ligand (PD-L1) found on many cancer cells and is licensed for the treatment of advanced malignant melanoma. We describe the first case of nivolumab-induced adrenalitis resulting in primary adrenal failure presenting with hyponatraemia in a 43-year-old man with malignant melanoma. The case highlights the potentially life-threatening complications of checkpoint inhibitors and the need for patient education and awareness of irAEs among the wider clinical community because such side effects require prompt recognition and treatment. Learning points: Nivolumab can cause primary adrenal insufficiency. Not all cases of hyponatraemia in patients with malignancy are due to SIADH. Any patient on a checkpoint inhibitor becoming unwell should have serum cortisol urgently measured and if in doubt hydrocortisone therapy should be initiated. Although hyponatraemia can occur in patients with ACTH deficiency, the possibility of primary adrenal failure should also be considered and investigated by measurement of renin, aldosterone and ACTH. Patients receiving checkpoint inhibitors require education on the potential risks of hypocortisolaemia. PET imaging demonstrated bilateral increased activity consistent with an autoimmune adrenalitis.

IGF-I measurements in the monitoring of GH therapy

Growth hormone replacement therapy has been used regularly in adult Growth hormone deficiency since the availability of recombinant GH in the 1980’s. GH replacement improves quality of life, bone turnover markers, cardiovascular risk markers and adverse body composition. Originally, GH doses in replacement regimes were determined by weight and surface area and dose increases based on body composition outcomes analogous to pediatric practice. These regimens led to significant side effects related to excess GH, arthralgias, headaches and peripheral edema and IGF-I levels above the upper limit of the reference range. Newer treatment regimes therefore account for known factors affecting serum GH and IGF-I levels, i.e. age, gender, estrogen replacement and pre-treatment IGF-I levels. Monitoring is now via clinical symptomatology combined with serum total IGF-I levels, potentially this avoids excessive GH exposure and allows monitoring of compliance and dose titration. There is a lack of data relating IGF-I to biological endpoints, but analysis suggests that dose titration of IGF-I to the upper half of the age and gender related reference range is acceptable. The use of reliable IGF-I assays and extensive age and gender related reference ranges is necessary and centralized monitoring is preferable. Free IGF-I and bioavailable IGF-I measurements are available but their use in the monitoring of GH replacement remains to be determined.