Lanreotide for the treatment of acromegaly

Analysis of Nephrolithiasis Treatment in Highest Reference Hospital-Occurrence of Acromegaly in the Study Group

BACKGROUND

Urolithiasis is one of the most common diseases of the urinary system, the incidence of which is assumed to be up to 100,000 cases per million (10% of the population). The cause of it is dysregulation of renal urine excretion. Acromegaly is a very rare endocrine disorder that causes a somatotropic pituitary adenoma producing higher amounts of growth hormone. It occurs approximately in 80 cases per million (about 0.008% of the population). One of the acromegaly complications may be urolithiasis.

METHODS

Clinical and laboratory results of 2289 patients hospitalized for nephrolithiasis in the highest reference hospital were retrospectively analyzed, distinguishing a subgroup of patients with acromegaly. Statistical analysis was performed to compare the prevalence of the disease in the analyzed subgroup with the epidemiological results available in up-to-date literature.

RESULTS

The distribution of nephrolithiasis treatment was definitely in favor of non-invasive and minimally invasive treatment. The methods used were as follows: ESWL (61.82%), USRL (30.62%), RIRS (4.15%), PCNL (3.1%), and pyelolithotomy (0.31%). Such a distribution limited the potential complications of the procedures while maintaining the high effectiveness of the treatment. Among two thousand two hundred and eighty-nine patients with urolithiasis, two were diagnosed with acromegaly before the nephrological and urological treatment, and seven were diagnosed de novo. Patients with acromegaly required a higher percentage of open surgeries (including nephrectomy) and also had a higher rate of kidney stones recurrence. The concentration of IGF-1 in patients with newly diagnosed acromegaly was similar to those treated with somatostatin analogs (SSA) due to incomplete transsphenoidal pituitary surgery.

CONCLUSIONS

In the population of patients with urolithiasis requiring hospitalization and interventional treatment compared to the general population, the prevalence of acromegaly was almost 50-fold higher (p = 0.025). Acromegaly itself increases the risk of urolithiasis.

The Use of Lanreotide in the Treatment of Congenital Hyperinsulinism

CONTEXT

Congenital hyperinsulinism (HI) results in severe, persistent hypoglycemia and is associated with high risk of neurodevelopmental deficits. Sixty percent of HI cases are unresponsive to diazoxide, the only Food and Drug Administration-approved drug. Somatostatin analogs are used off-label as second-line treatment; the long-acting somatostatin analogue, lanreotide, has been used to treat HI over the past decade. Existing reports are limited to small case series.

OBJECTIVE

To assess the effectiveness and safety of lanreotide in individuals with HI.

DESIGN

Retrospective cohort study of individuals with HI treated with lanreotide between 2015 and 2020.

SETTING

The Congenital Hyperinsulinism Center at The Children's Hospital of Philadelphia.

PATIENTS

Fifty-four individuals with hyperinsulinism treated with lanreotide.

MAIN OUTCOME MEASURES

Fasting duration with plasma glucose > 70 mg/dL; frequency of lanreotide-associated side effects.

RESULTS

The median duration of lanreotide therapy was 28.7 (2.8-64.5) months. Thirty-four patients (63%) had HI due to inactivating mutations of the adenosine 5'-triphosphate (ATP) sensitive potassium channel (KATP-HI), and 39% had undergone a pancreatectomy. Of 52 patients receiving other HI therapies, 22 (42%) were able to discontinue other treatments and were managed on lanreotide alone. Fasting duration with plasma glucose > 70 mg/dL was significantly longer during therapy with lanreotide compared to prior to lanreotide initiation (8.6 ± 6.5 vs 5.1 ± 4.7 hours, P = 0.001). The most common side effects were subcutaneous nodules (26%) and gallstones (11%).

CONCLUSIONS

Lanreotide is a well-tolerated treatment for patients with HI. It results in a longer duration of fasting and a simplification of treatment regimens.

Bioanalysis of lanreotide in dog plasma using liquid chromatography-tandem mass spectrometry and its application in a pharmacokinetic study of beagle dogs after single subcutaneous injection

Lanreotide is similar to a naturally occurring hormone, somatostatin; thus, it may be used to treat acromegaly or metastatic gastroenteropancreatic neuroendocrine tumours. Here, a bioanalytical method coupling ultra-performance liquid chromatography with tandem mass spectrometry to quantify lanreotide and an internal standard (IS) was developed and validated in dog plasma. The plasma samples were extracted using typical protein precipitation processes. The analyte and internal standard were separated on Phenomenex Kinetex® C18 with 0.1% formic acid and acetonitrile in the mobile phase at a flow rate of 0.4 mL/min. The fragmentation of precursor ions to product ions was optimized at m/z 548.8 → 170.0 for lanreotide [M + 2H]²⁺ and 472.2 → 436.2 for IS [M + H]⁺. The peak retention times of lanreotide and IS were 1.09 min and 1.22 min, respectively. The calibration curve samples in dog plasma ranged from 0.3 to 1000 ng/mL and showed good linearity, with a correlation coefficient of r²=0.9996. The lower limit of quantitation was 0.3 ng/mL. The intra- and inter-day precision (relative standard deviation) values for each quality control level were < 9.7 % and < 9.3 %, respectively; intra- and inter-day accuracy were < 109.3% and < 110.4%, respectively. Lanreotide in dog plasma was stable in various conditions. The maximum plasma concentration of lanreotide in male beagle dogs after subcutaneous injection of Somatuline® (lanreotide) Autogel 120 mg was 88.1 ng/mL. The half-life (T_1/2) of lanreotide in beagle dogs was long, approximately 198.6 h; the area under the plasma-concentration curve from 0 to 840 h (day 35) was 6,995 ng⋅h/mL. This novel quantification method using UPLC-MS/MS was successfully applied to the pharmacokinetic analysis of lanreotide in dog plasma. The results will assist future studies of drug formulation and repurposing.

International Union of Basic and Clinical Pharmacology. CV. Somatostatin Receptors: Structure, Function, Ligands, and New Nomenclature

Somatostatin, also known as somatotropin-release inhibitory factor, is a cyclopeptide that exerts potent inhibitory actions on hormone secretion and neuronal excitability. Its physiologic functions are mediated by five G protein-coupled receptors (GPCRs) called somatostatin receptor (SST)1-5. These five receptors share common structural features and signaling mechanisms but differ in their cellular and subcellular localization and mode of regulation. SST₂ and SST₅ receptors have evolved as primary targets for pharmacological treatment of pituitary adenomas and neuroendocrine tumors. In addition, SST₂ is a prototypical GPCR for the development of peptide-based radiopharmaceuticals for diagnostic and therapeutic interventions. This review article summarizes findings published in the last 25 years on the physiology, pharmacology, and clinical applications related to SSTs. We also discuss potential future developments and propose a new nomenclature.

Implications of Somatostatin Analogues in the Treatment of Acromegaly

Octreotide has an important role in the medical management of acromegaly. Its place in the management of acromegaly as an adjuvant therapy after neurosurgery is well established with a well-demonstrated efficacy. It can also be used in certain clinical conditions as a neoadjuvant treatment. Clinicians and patients should be aware of the possible side effects of octreotide treatment.

Somatostatin receptors: from signaling to clinical practice

Somatostatin is a peptide with a potent and broad antisecretory action, which makes it an invaluable drug target for the pharmacological management of pituitary adenomas and neuroendocrine tumors. Somatostatin receptors (SSTR1, 2A and B, 3, 4 and 5) belong to the G protein coupled receptor family and have a wide expression pattern in both normal tissues and solid tumors. Investigating the function of each SSTR in several tumor types has provided a wealth of information about the common but also distinct signaling cascades that suppress tumor cell proliferation, survival and angiogenesis. This provided the rationale for developing multireceptor-targeted somatostatin analogs and combination therapies with signaling-targeted agents such as inhibitors of the mammalian (or mechanistic) target of rapamycin (mTOR). The ability of SSTR to internalize and the development of rabiolabeled somatostatin analogs have improved the diagnosis and treatment of neuroendocrine tumors.

Extra-hepatic Acromegaly

After the introduction of somatostatin analogs (LA-SMSA) and the growth hormone (GH) receptor antagonist, pegvisomant (Peg-v) normal serum insulin-like growth factor-1 (IGF-1) concentrations in virtually every patients with acromegaly is possible. The impact of these products on the GH-IGF1 axis is completely different. We advocate that LA-SMSA may normalize serum IGF1 levels in the presence of elevated GH actions in extra-hepatic tissues. This results in persistent peripheral disease activity that we call 'extra-hepatic acromegaly'. Peg-v competitively blocks systemic GH action and results in a GH serum level increase. Therefore high doses of Peg-v are necessary to control IGF-1. Since the mode of action differs between these products, it is questionable if identical IGF-1 levels, during Peg-v or LA-SMSA are really identical representations of the biochemical situation. With the traditional biomarkers medical treatment is therefore difficult to monitor with the traditional biomarkers. Additionally, Peg-v and LA-SMSA could be ideal combination since they have different mode of actions. We believe that the time has come to challenge the existing concepts of treatment and monitoring of patients with acromegaly.

Preparation, characterization and related in vivo release, safety and toxicity studies of long acting lanreotide microspheres

The goal of this project was to prepare long-acting lanreotide acetate poly(lactic-co-glycolic acid) (PLGA) microspheres and to analyze the in vivo and in vitro release, safety and toxicology of these preparations. Long-acting lanreotide acetate PLGA microspheres that exhibited a 5-week slow-release period were prepared by a multiple-emulsion solvent evaporation method. Physical characterization, as well as the analysis of the in vivo and in vitro release, safety, acute toxicity and chronic toxicity of the lanreotide microspheres, were conducted in animal models in rats, guinea pigs, rabbits and beagle dogs. The lanreotide acetate PLGA microspheres prepared by multiple-emulsion solvent evaporation had smooth surfaces, uniform particle size and stable lanreotide loading. In vivo and in vitro experiments showed that the lanreotide acetate PLGA microspheres could continuously release lanreotide for 5 weeks. The safety of these long acting lanreotide microspheres was good in the following animal models: active systemic anaphylaxis test in guinea pigs, passive cutaneous anaphylaxis test in rats, hemolytic test in rabbits, local skin irritation test after subcutaneous administration in rabbits and muscle stimulation test in rabbits. Furthermore, no significant acute toxicity or chronic toxicity was observed after administration of lanreotide acetate PLGA microspheres in beagle dogs at dosages up to 22 mg/kg. The lanreotide acetate PLGA microspheres that were prepared in this study exhibited beneficial characteristics in apparent property and structural stability, as well as in release trends in vivo and in vitro.

Clinical experience with lanreotide for the treatment of acromegaly

Acromegaly is a rare disease, characterized in adults by its distinctive appearance of facial dysmorphism and swollen fingers. It is caused by an overproduction of growth hormone (GH) in more than 99% of patients and in nearly all cases is due to a pituitary adenoma. If surgical resection of the adenoma is not effective, medical treatment is usually the next treatment option. The most commonly used medications are the somatostatin analogues octreotide and lanreotide. Lanreotide is a synthetic somatostatin analogue and is available as slow-release microparticle (every 7-14 days) and prolonged-release liquid (autogel, every 28-56 days) formulations. Lanreotide autogel is a supersaturated aqueous formulation for deep subcutaneous injection and is sold in a ready-to-use prefilled syringe. This ease of use allows self or partner administration at home. This article reviews the use of lanreotide in the treatment of acromegaly and its advantages and disadvantages compared with other somatostatin analogues.

Resistance to somatostatin analogs in acromegaly

Somatostatin analogs (SA) are widely used in acromegaly, either as first-line or adjuvant treatment after surgery. First-line treatment with these drugs is generally used in the patients with macroadenomas or in those with clinical conditions so severe as to prevent unsafe reactions during anesthesia. Generally, the response to SA takes into account both control of GH and IGF-I excess, with consequent improvement of clinical symptoms directly related to GH and IGF-I excess, and tumor shrinkage. This latter effect is more prominent in the patients treated first-line and bearing large macroadenomas, but it is also observed in patients with microadenomas, even with little clinical implication. Predictors of response are patients' gender, age, initial GH and IGF-I levels, and tumor mass, as well as adequate expression of somatostatin receptor types 2 and 5, those with the highest affinity for octreotide and lanreotide. Only sporadic cases of somatostatin receptor gene mutation or impaired signaling pathways have been described in GH-secreting tumors so far. The response to SA also depends on treatment duration and dosage of the drug used, so that a definition of resistance based on short-term treatments using low doses of long-acting SA is limited. Current data suggest that response to these drugs is better analyzed taking together biochemical and tumoral effects because only the absence of both responses might be considered as a poor response or resistance. This latter evidence seems to occur in 25% of treated patients after 12 months of currently available long-acting SA.

Anticonvulsant neuropeptides as drug leads for neurological diseases

Anticonvulsant neuropeptides are best known for their ability to suppress seizures and modulate pain pathways. Galanin, neuropeptide Y, somatostatin, neurotensin, dynorphin, among others, have been validated as potential first-in-class anti-epileptic or/and analgesic compounds in animal models of epilepsy and pain, but their therapeutic potential extends to other neurological indications, including neurodegenerative and psychatric disorders. Disease-modifying properties of neuropeptides make them even more attractive templates for developing new-generation neurotherapeutics. Arguably, efforts to transform this class of neuropeptides into drugs have been limited compared to those for other bioactive peptides. Key challenges in developing neuropeptide-based anticonvulsants are: to engineer optimal receptor-subtype selectivity, to improve metabolic stability and to enhance their bioavailability, including penetration across the blood–brain barrier (BBB). Here, we summarize advances toward developing systemically active and CNS-penetrant neuropeptide analogs. Two main objectives of this review are: (1) to provide an overview of structural and pharmacological properties for selected anticonvulsant neuropeptides and their analogs and (2) to encourage broader efforts to convert these endogenous natural products into drug leads for pain, epilepsy and other neurological diseases.

Hypothesis: Extra-hepatic acromegaly: a new paradigm?

Medical treatment of acromegaly with long-acting somatostatin analogs (LA-SMSA) and the GH receptor antagonist, pegvisomant (PEGV), has made it possible to achieve normal serum IGF1 concentrations in a majority of patients with acromegaly. These two compounds, however, impact the GH-IGF1 axis differently, which challenges the traditional biochemical assessment of the therapeutic response. We postulate that LA-SMSA in certain patients normalizes serum IGF1 levels in the presence of elevated GH actions in extra-hepatic tissues. This may result in persistent disease activity for which we propose the term extra-hepatic acromegaly. PEGV, on the other hand, blocks systemic GH actions, which are not necessarily reliably reflected by serum IGF1 levels, and this treatment causes a further elevation of serum GH levels. Medical treatment is therefore difficult to monitor with the traditional biomarkers. Moreover, the different modes of actions of LA-SMSA and PEGV make it attractive to use the two drugs in combination. We believe that it is time to challenge the existing concepts of treatment and monitoring of patients with acromegaly.