Cholecalciferol Use Is Associated With a Decreased Risk of Incident Morphometric Vertebral Fractures in Acromegaly.

CONTEXT: Skeletal fragility is observed in 30% to 60% of acromegaly patients, representing an emerging complication of the disease that increases disability. Despite several studies having investigated the clinical and hormonal prognostic factors for the occurrence of vertebral fractures (VFs) in acromegaly, very few data are available on their prevention/treatment including the effect of vitamin D (VD) supplementation, which has been reported to have a fracture-protective effect in several studies in patients with osteoporosis. OBJECTIVE: We aimed to investigate the role of cholecalciferol (D3) supplementation in the prevention of incident VFs (i-VFs) in acromegaly. METHODS: A longitudinal, retrospective and multicenter study was performed on 61 acromegaly patients treated and untreated with D3 supplementation. RESULTS: Twenty-six patients were treated with D3 supplementation according to clinical guidelines. The median D3 weekly dosage was 8500 IU (interquartile range [IQR]: 3900). The median duration of D3 supplementation was 94 months (IQR: 38). At last follow-up, i-VFs were diagnosed in 14 patients (23%). I-VFs were less prevalent in patients on D3 supplementation (14.3% of cases) compared to patients not treated with D3 (85.7%; P = .02). The final level of serum V25OH-D was significantly lower in patients who developed i-VFs (28.6 ng/mL, IQR: 4.1) compared to patients who did not develop i-VFs (34.2 ng/mL, IQR: 9.6; P = .05). The logistic regression confirmed the protective role of D3 supplementation on the occurrence of i-VFs (odds ratio: 0.16; 95% CI, 0.03-0.79; P = .01). CONCLUSION: It is likely that D3 supplementation could lead to a reduction in i-VFs in acromegaly.

A pharmacophore screening approach of homeopathic phenols for a renovated design of fragment-optimized Bauhiniastatin-1 as a drug against acromegaly.

OBJECTIVE: Acromegaly is a fatal and chronic disease that is caused by the abnormal secretion of growth hormone (GH) by the pituitary adenoma or pituitary tumor, resulting in an increased circulated concentration of insulin-like growth factors 1 (IGF-1), where in most of the cases it is secreted by a pituitary tumor. Higher levels of GH cause an increase in IGF-1 in the liver leading to multiple conditions such as cardiovascular diseases, glucose imbalance, cancer, and sleep apnea. Medical treatments such as surgery and radiotherapy can be used as the first choice of patients; however, specified human growth hormone control should be an essential treatment strategy due to an incidence rate of 0.2-1.1 yearly. Therefore, the main focus of this study is to develop a novel drug for treating acromegaly by exploiting medicinal plants that have been screened using phenol as a pharmacophore model to identify target therapeutic medicinal plant phenols. MATERIALS AND METHODS: The screening identified thirty-four pharmacophore matches of medicinal plant phenols. These were selected as suitable ligands and were docked against the growth hormone receptor to calculate their binding affinity. The candidate with the highest screened score was fragment-optimized and subjected to absorption, distribution, metabolism, and excretion (ADME) analysis, in-depth toxicity predictions, interpretation of Lipinski's rule, and molecular dynamic simulations to check the behavior of the growth hormone with the fragment-optimized candidate. RESULTS: The highest docking energy was calculated as -6.5 K/mol for Bauhiniastatin-1. Enhancing the performance of Bauhiniastatin-1 against the growth hormone receptor with fragment optimization portrayed that human growth hormone inhibition can be executed in a more efficient and better way. Fragment-optimized Bauhiniastatin-1 (FOB) was predicted with high gastrointestinal absorption, a water solubility of -2.61 as soluble, and synthetic accessibility of 4.50, achieving Lipinski's rule of 5, with low organ toxicity prediction and interpreting a positive behavior against the targeted protein. The discovery of a de novo drug candidate was confirmed by the docking of fragment-optimized Bauhiniastatin-1 (FOB), which had an energy of -4,070 Kcal/mol. CONCLUSIONS: Although successful and completely harmless, present healthcare treatment does not always eradicate the disease in some individuals. Therefore, novel formulas or combinations of currently marketed medications and emergent phytochemicals will provide new possibilities for these instances.

Looking at the spine in controlled Acromegaly.

Skeletal fragility with high risk of vertebral fractures (VFs) is an emerging complication of growth hormone (GH) hypersecretion. VFs often coexist with spine arthropathy and both clinical conditions negatively impact on quality of life of acromegalic subjects. Management of spine osteopathy and arthropathy in acromegaly could be challenging since both complications can persist or even progress after biochemical control of disease. This article analyzes the latest evidence about possible pathophysiological links between VFs and spine arthropathy in active and controlled acromegaly, as well as the diagnostic and therapeutic aspects concerning the holistic management of acromegalic osteo-arthropathy.

Characterization of vitamin D metabolism in active acromegaly in the setting of bolus (150,000 IU) cholecalciferol treatment.

PURPOSE: To reveal distinctive features of vitamin D metabolism in patients with active acromegaly compared to healthy individuals, particularly in the setting of cholecalciferol treatment. METHODS: The study group included 34 adults with active acromegaly, and the control group included 30 apparently healthy adults with similar age, sex, and BMI. All participants received a single dose (150,000 IU) of cholecalciferol aqueous solution orally. Laboratory assessments including serum vitamin D metabolites (25(OH)D3, 25(OH)D2, 1,25(OH)2D3, 3-epi-25(OH)D3 and 24,25(OH)2D3), free 25(OH)D, vitamin D-binding protein (DBP) and parathyroid hormone (PTH) as well as serum and urine biochemical parameters were performed before the intake and on Days 1, 3, and 7 after the administration. All data were analyzed with nonparametric statistics. RESULTS: Patients with acromegaly had tendency to lower baseline 25(OH)D3 levels (p = 0.05) and lower 25(OH)D3 levels (p < 0.05) during the follow-up. They were also characterized by PTH suppression (lower baseline PTH levels and lower prevalence of secondary hyperparathyroidism), altered production of main vitamin D metabolites (higher 1,25(OH)2D3 and lower 24,25(OH)2D3 levels with corresponding lower 25(ОН)D3/1,25(ОН)2D3 and higher 25(ОН)D3/24,25(ОН)2D3 ratios) as well as concordant biochemical features (higher levels of serum phosphorus and albumin-adjusted calcium levels) throughout the study (p < 0.05). The acromegaly group showed an increase in DBP levels after cholecalciferol intake as opposed to the control group (p < 0.05) and had lower increase in free 25(OH)D levels (p < 0.05). Δ25(OH)D3 was similar between the groups (p > 0.05), showed a negative correlation with the disease activity markers-both IGF-1 levels (r = -0.44, p < 0.05) and fasting GH levels (r = -0.56, p < 0.05)-and lacked correlation with BMI in the acromegaly group (p > 0.05). CONCLUSION: Patients with active acromegaly have dysregulated vitamin D metabolism characterized by higher 1,25(ОН)2D3, lower 24,25(ОН)2D3 and altered DBP production. The response to vitamin D supplementation in acromegaly patients might be influenced by hormonal excess. Obtained results require reproducibility check and further study to develop specific clinical recommendations. TRIAL REGISTRATION: NCT04844164 (release date: April 9, 2021; retrospectively registered).

Pharmacological Acromegaly Treatment: Cost-Utility and Value of Information Analysis.

OBJECTIVES: To conduct a cost-utility analysis comparing drug strategies involving octreotide, lanreotide, pasireotide, and pegvisomant for the treatment of patients with acromegaly who have failed surgery, from a Brazilian public payer perspective. METHODS: A probabilistic cohort Markov model was developed. One-year cycles were employed. The patients started at 45 years of age and were followed lifelong. Costs, efficacy, and quality of life parameters were retrieved from the literature. A discount rate (5%) was applied to both costs and efficacy. The results were reported as costs per quality-adjusted life year (QALY), and incremental cost-effectiveness ratios (ICERs) were calculated when applicable. Scenario analyses considered alternative dosages, discount rate, tax exemption, and continued use of treatment despite lack of response. Value of information (VOI) analysis was conducted to explore uncertainty and to estimate the costs to be spent in future research. RESULTS: Only lanreotide showed an ICER reasonable for having its use considered in clinical practice (R$ 112,138/US$ 28,389 per QALY compared to no treatment). Scenario analyses corroborated the base-case result. VOI analysis showed that much uncertainty surrounds the parameters, and future clinical research should cost less than R$ 43,230,000/US$ 10,944,304 per year. VOI also showed that almost all uncertainty that precludes an optimal strategy choice involves quality of life. CONCLUSIONS: With current information, the only strategy that can be considered cost-effective in Brazil is lanreotide treatment. No second-line treatment is recommended. Significant uncertainty of parameters impairs optimal decision-making, and this conclusion can be generalized to other countries. Future research should focus on acquiring utility data.

Cost-effectiveness analysis of second-line pharmacological treatment of acromegaly in Spain.

Objective: To estimate the cost-effectiveness of second-line pharmacological treatments in patients with acromegaly resistant to first-generation somatostatin analogues (FG SSA) from the Spanish National Health System (NHS) perspective.Methods: A Markov model was developed to analyze the cost-effectiveness of pegvisomant and pasireotide in FG SSA-resistant acromegaly, simulating a cohort of patients from the treatment beginning to death. Treatment with pegvisomant or pasireotide was compared to FG SSA retreatment. Efficacy data were obtained from clinical trials and utilities from the literature. Direct health costs were obtained from Spanish sources (€2018).Results: The Incremental Cost Effectiveness Ratio (ICER) of pegvisomant vs. FG SSA was €85,869/Quality-adjusted life years (QALY). The ICER of pasireotide vs. FG SSA was €551,405/QALY. The ICER was mainly driven by the incremental efficacy (4.41 QALY for pegvisomant vs. FG SSA and 0.71 QALY for pasireotide vs. FG SSA), with a slightly lower increase in costs with pegvisomant (€378,597 vs. FG SSA) than with pasireotide (€393,151 vs. FG SSA).Conclusion: The ICER of pasireotide compared to FG SSA was six times higher than the ICER of pegvisomant vs. FG SSA. Pegvisomant is a more cost-effective alternative for the treatment of acromegaly in FG SSA-resistant patients in the Spanish NHS.

Surgical-pharmacological interactions in the treatment of acromegaly.

INTRODUCTION: Acromegaly requires a multimodal treatment approach that includes surgery by an expert pituitary neurosurgeon, pharmacological treatment with one or more of the available drugs and radiation therapy. These treatment alternatives are not mutually exclusive but rather complement each other when properly indicated in the individual patient. In this review, we summarize and analyze the available data concerning the choice of the surgical approach (microscopy vs. endoscopy) and the interactions between medical treatment with somatostatin analogs and pituitary surgery. AREAS COVERED: Technical aspects, complications and outcome of transsphenoidal surgery (TSS); Advantages and disadvantages of the microscopic and endoscopic approaches; Safety and efficacy of somatostatin analogs (SSA); Primary pharmacological therapy versus primary TSS; Benefits of the preoperative treatment with SSA; and the effect of surgical tumor debulking in the therapeutic response to SSA. EXPERT COMMENTARY: Continuing efforts at improving surgical techniques and at generating more efficacious pharmacological therapies for acromegaly are likely to improve the outcome of these patients. However, an integral approach of the patient aimed not only at achieving biochemical criteria of cure but also at treating the individual comorbidities is mandatory to improve the quality of life of these patients and to reduce their mortality rate.

Octreotide LAR treatment of acromegaly in "real life": long-term outcome at a tertiary care center.

OBJECTIVE: To report our day-to day experience with the long-term use of octreotide LAR in the treatment of acromegaly. PATIENTS AND METHODS: Patients with acromegaly managed between 2003 and 2012 with octreotide LAR for a median of 27 months (interquartile ranges 12-60) and who had not received radiation therapy or concomitant treatment with cabergoline were retrospectively evaluated. Both primarily treated patients (n = 33) and patients who received octreotide after failed pituitary surgery (adjunctive treatment, n = 124) were included. Full biochemical response was defined as the achievement of a GH <2.5 ng/mL and an IGF-1 <1.2 times the upper limit of normal (× ULN); we also evaluated efficacy using a GH cut off of <1 ng/mL. RESULTS: Over 60% of the patients achieved a GH of <2.5 ng/mL. The combined GH (<2.5 ng/mL) and IGF-1 (<1.2 × ULN) target was achieved by 35.5 and 33.6% of the patients treated primarily and adjunctively, respectively; these figures dropped to 22.6 and 23% when using a GH target of <1 ng/mL. All patients reported a significant improvement in acromegalic symptoms. Lower pretreatment GH and IGF-1 levels were both associated with a higher probability of achieving the composite biochemical target. CONCLUSION: Currently recommended GH and IGF-1 targets are reached by <36% of patients treated with octreotide LAR in a day-to day practice context. Nevertheless, in most instances a clinical benefit and an improvement in biochemical markers can be clearly documented.

The effect of somatostatin analogs on vitamin D and calcium concentrations in patients with acromegaly.

PURPOSE: The goals of this study were to determine: (1) 25OH vitamin D (25OHD) and calcium levels in patients with acromegaly and their association with insulin-like growth factor (IGF-1) and (2) whether somatostatin analog (SSA) therapy effects calcium and 25OHD levels. METHODS: 125 patients with acromegaly were studied. Serum calcium and 25OHD levels were compared prior to and after vitamin D supplementation between patients receiving versus not receiving SSA in whom medical therapy included pegvisomant and/or dopamine agonists. Calcium and 25OHD levels were also evaluated longitudinally prior to and during short-term (mean 3 months, range 1-5) and long-term (mean 49 months, range 7-180) SSA administration. Vitamin D2 50,000 units weekly were given to 3 patients in the cross sectional and 1 in the longitudinal group; 400-4,000 units/day of D3 were given to 11 and 5 in respective groups. RESULTS: In patients with a comparable mean IGF-1 index and season of testing, mean serum levels of 25OHD prior to vitamin D supplementation did not differ in patients receiving versus not receiving SSA (30 ± 3 vs. 30 ± 1 ng/ml, p = 0.99) and the prevalence of vitamin D sufficiency was similar between SSA and non SSA groups (42 vs. 57%, p = 0.20), prior to vitamin D supplementation. In patients with a comparable mean IGF-1 index and season of testing, mean serum 25OHD levels in patients increased after vitamin D supplementation in both those who were (37 ± 2 ng/ml, N = 23, p = 0.007) and were not receiving SSA (35 ± 1 ng/ml, N = 69, p = 0.005) compared to pre-D supplementation levels but were not different between these groups, p = 0.95) after D supplementation. Calcium and albumin were normal throughout longitudinal follow up. Calcium correlated with IGF-1 index (ρ = 0.29, p = 0.001, N = 125). In the longitudinal subset, serum calcium decreased transiently, in patients receiving short-term SSA (pretreatment 9.9 ± 0.1 mg/dl vs. short-term SSA 9.5 ± 0.1, p = 0.004). After long-term SSA therapy, calcium increased compared to levels on short-term therapy (9.8 ± 0.1 mg/dl vs. 9.5 ± 0.1, p = 0.017) and were unchanged compared to baseline. Mean vitamin D levels were sufficient at baseline prior to SSA therapy (33 ± 5.0 ng/ml), and did not change during short term (29 ± 6 ng/ml, p = 0.85) and long term SSA therapy (35 ± 5 ng/ml, p = 0.43). CONCLUSIONS: Prior to and after vitamin D supplementation, patients with acromegaly receiving long-term SSA had vitamin D levels similar to those receiving other therapies, suggesting that long-term SSA therapy does not affect serum vitamin D. However, given the limitations of this retrospective study, further prospective studies evaluating the impact of SSA on vitamin D levels are necessary to confirm these findings definitively. Calcium levels are positively associated with IGF-1 index in patients with acromegaly. There is a transient decrease in calcium levels with short-term SSA use. The acute effect of SSA on calcium does not appear to be mediated by albumin, 25OHD or PTH and resolves with long-term SSA treatment. The transient decrease in calcium with short-term SSA use resolved with long-term SSA therapy.

Pegvisomanto para o tratamento da acromegalia / Pegvisomanto for the treatment of acromegaly

CONTEXTO: A acromegalia é uma doença rara, debilitante e desfigurante, decorrente do excesso de produção do hormônio do crescimento (GH) e, consequentemente, do fator de crescimento semelhante à insulina (insulin-like growth factor I - IGF-I), que leva a um crescimento excessivo do esqueleto e dos tecidos moles. Está associada com um aumento da mortalidade e redução da qualidade de vida dos pacientes. A acromegalia está associada com um aumento da mortalidade e redução da qualidade de vida. A morbidade e mortalidade da doença estão correlacionadas com os níveis de GH e, desta forma, a utilização de terapias eficientes é importante. O tratamento pode ser feito por meio de cirurgia, radioterapia ou uso de medicamentos. É chamado de tratamento primário aquele usado como primeiro tratamento (em geral com o intuito de controlar a doença em longo prazo). O tratamento secundário tem como objetivo o controle da doença naqueles pacientes não compensados após realização de tratamento primário. Somavert® (pegvisomanto) é indicado para o tratamento da acromegalia em pacientes que apresentaram resposta inadequada à cirurgia e/ou à radioterapia e para aqueles pacientes cujo tratamento médico com análogos da somatostatina não normalizou as concentrações séricas de IGF-I ou não foi tolerado. EVIDÊNCIAS CIENTÍFICAS: Além da análise dos estudos apresentados pelo demandante, a Secretaria-Executiva da CONITEC realizou busca na literatura por artigos científicos, com o objetivo de encontrar Revisões Sistemáticas e Ensaios Clínicos Randomizados (ECR), considerados a melhor evidência para avaliar a eficácia de uma tecnologia usada para tratamento. As bases pesquisadas foram Medline® (via PubMed), The Cochrane Library (via Bireme) e CRD (Centre for Reviews and Dissemination). RECOMENDAÇÃO DA CONITEC: em decorrência da limitação de dados que demonstrem a efetividade e a segurança do medicamento por períodos mais prolongados e, principalmente, por uma relação de custo-efetividade bastante desfavorável, os membros da CONITEC, presentes na reunião do plenário do dia 02/08/2012, não recomendaram a incorporação do medicamento pegvisomanto para o tratamento da acromegalia no SUS. CONSULTA PÚBLICA: A consulta pública foi realizada do dia 13/08/2012 ao dia 22/08/2012. Foram recebidas 16 contribuições. Delas, a maioria foi encaminhada por especialistas de instituições de saúde/hospitais, seguido de contribuições de instituições de ensino, empresa e de sociedades médicas. As contribuições apresentadas na consulta pública não acrescentaram novas evidências científicas sobre a utilidade do medicamento, além daquelas já apresentadas pelo demandante e avaliadas pela CONITEC. Desta forma, as conclusões do relatório da CONITEC são mantidas no sentido de que as evidências existentes são limitadas para a incorporação do medicamento no SUS. Além disso, algumas das contribuições trazem a preocupação sobre o uso incorreto deste medicamento caro no SUS, uma vez que as alternativas terapêuticas atualmente oferecidas (Cirurgia, Radioterpaia e Medicamentos) são utilizadas de maneira inadequada, o que poderá levar a que este medicamento seja prescrito de maneira desnecessária para muitos pacientes. Desta forma, antes da incorporação do pegvisomanto é necessário que se garanta que as atuais terapias oferecidas, que já são bastante onerosas para SUS, sejam utilizadas de maneira otimizada. Ao contrário, estaremos em risco de aumentar ainda mais os custos do tratamento da acromegalia com utilização inadequada do Pegvisomanto. Neste sentido, devemos considerar que os valores bastante elevados de custo por QALY (ao redor de 230 mil reais) e por ano de vida ganho (ao redor de 820 mil reais) para a utilização do Pegvisomanto, podem ficar ainda muito mais elevados se a medicação for utilizada de maneira inadequada. DELIBERAÇÃO FINAL: Os membros da CONITEC presentes na 9ª reunião do plenário do dia 11/10/2012, por unanimidade, ratificaram a decisão de não recomendar a incorporação do medicamento pegvisomanto para o tratamento da Acromegalia. DECISÃO: PORTARIA SCTIE-MS N.º 1 de 17 de janeiro de 2013 - Torna pública a decisão de não incorporar o medicamento pegvisomanto para o tratamento da acromegalia no Sistema Único de Saúde (SUS).

From somatostatin to octreotide LAR: evolution of a somatostatin analogue.

BACKGROUND: Acromegaly is characterized by overproduction of growth hormone (GH) by the pituitary gland. GH stimulates the synthesis of insulin-like growth factor-I (IGF-I), and the somatic growth and metabolic dysfunction that characterize acromegaly are a consequence of elevated GH and IGF-I levels. Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare, slow-growing neoplasms that have usually metastasized by the time of diagnosis. The majority of GEP-NETs are carcinoid tumors whose syndrome is caused by the hypersecretion of biogenic amines, peptides and polypeptides responsible for the principal symptoms of diarrhea and flushing. METHODS: The MEDLINE and EMBASE databases were searched for preclinical and clinical studies of octreotide (Sandostatin* ), a potent synthetic somatostatin analogue, in patients with acromegaly or GEP-NETs. OBJECTIVE: This article reviews the 20 years of clinical experience with octreotide and the impact it has made in patients with acromegaly or GEP-NETs. RESULTS: Octreotide has proven to be an essential component in the management strategy of acromegaly and GEP-NETs over the past 20 years. The multiple beneficial effects of octreotide throughout the body, combined with its established safety profile (the most common adverse effects are injection-site pain and gastrointestinal events), have made it an appealing option for clinicians. The advent of the long-acting release (LAR) formulation of octreotide provided additional benefits to patients through monthly administration, while maintaining the efficacy and tolerability profile of the daily subcutaneous formulation. CONCLUSIONS: Octreotide is a potent synthetic somatostatin analogue that has become the mainstay of medical therapy for tumor control in neuroendocrine disorders such as acromegaly and GEP-NETs. The development of octreotide LAR offered a further advancement; less frequent dosing provided valuable benefits in quality of life to patients, with equivalent efficacy and tolerability. Moreover, recent results from the PROMID study have confirmed the antiproliferative effect of octreotide LAR in patients with well-differentiated metastatic GEP-NETs of the midgut. New therapeutic uses of octreotide are currently under investigation in a variety of clinical settings.

Pasireotide--a somatostatin analog for the potential treatment of acromegaly, neuroendocrine tumors and Cushing's disease.

Pasireotide (SOM-230) is a small somatostatin (SST) analog that is being developed by Novartis Pharma AG for the potential treatment of acromegaly, Cushing's disease and neuroendocrine tumors; the compound is currently in phase III clinical trials for Cushing's disease. Pasireotide exhibits high binding affinity to four of the five human (h)SST receptor subtypes, with IC50 values for hSST5 > hSST2 > hSST3 > hSST1; the compound displays no affinity for hSST4. The affinity profile of pasireotide resembles the profile of endogenous SSTs--a feature that is favorable given that different tumors exhibit differing SST receptor expression profiles. Pasireotide also exhibits a longer half-life than the clinically available SST analogs octreotide or lanreotide. Thus, this compound may be a better therapeutic agent than other analogs. In phase II clinical trials, pasireotide inhibited growth hormone (GH) secretion from GH-secreting pituitary tumors, controlled symptoms associated with metastatic carcinoid tumors, and inhibited adrenocorticotropic hormone secretion in Cushing's disease. However, a major advantage for pasireotide compared with octreotide was not demonstrated. Commonly encountered side effects for the compound included mild to moderate gastrointestinal events (diarrhea, abdominal discomfort, nausea and vomiting). The efficacy of pasireotide and any potential advantage over current therapies will need to be tested or validated in larger phase III clinical trials.

In vivo evaluation of a novel, orally bioavailable, small molecule growth hormone receptor antagonist.

IGF-I is regarded as the most sensitive marker of growth hormone (GH) secretion in both GH deficient individuals and in individuals with excessive GH production. Studies on the effect of inhibitors of GH action in normal experimental animals are difficult to evaluate due to the complex relationship and feed back mechanisms of the GH/IGF-I system and the hypothalamo-pituitary axis. To circumvent the GH/IGF-I feedback mechanisms, we have used hypophysectomized (HX) rats treated with GH to assess the potential of a new low molecular weight compound, BVT-A ((N-[5-(aminosulfonyl)-2-methylphenyl]-5-bromo-2-furamide), to act as a GH receptor antagonist in vivo. GH treatment of HX rats induced serum IGF-I, body weight and hepatic mRNA levels of IGF-I, IGFBP-3, ALS and the IGF-I and GH receptors. Co-treatment with BVT-A suppressed all the GH-induced effects. We conclude that the GH substituted HX rat is a useful model for studies on GH receptor antagonists, and for the first time, a small molecule GH receptor antagonist with in vivo activity has been revealed. This opens up for development of new drugs for diseases in which lowering of GH receptor activity would be beneficial.

McCune-Albright syndrome and acromegaly: effects of hypothalamopituitary radiotherapy and/or pegvisomant in somatostatin analog-resistant patients.

BACKGROUND: Acromegaly, which may be present in patients with McCune-Albright syndrome (MCAS), in association with café-au-lait spots, precocious puberty, and fibrous dysplasia, is often difficult to treat surgically because skull base bone dysplasia prevents the removal of the pituitary adenoma. Somatostatin analogs (SAs) generally give only partial responses. The use of radiotherapy (RT) is controversial because of a possible risk of bone sarcomatous transformation. AIM: This study was a retrospective analysis of the efficacy and adverse effects of different treatment modalities in six patients with both MCAS and acromegaly. PATIENTS AND METHODS: Because surgery was impossible and SA failed to normalize GH/IGF-I hypersecretion, five of the six patients received fractionated RT (45-55 Grays). Three patients (two with previous RT) were also prescribed pegvisomant. We analyzed the clinical features of acromegaly, GH, and IGF-I concentrations and bone radiological features. RESULTS: GH and IGF-I concentrations fell after RT (median follow-up, 5 yr; range, 0.5-9 yr). Symptoms of acromegaly improved in parallel. Bone sarcomatous transformation was only noted in one patient in a region (the mandible) outside the radiation field. RT alone and/or combined with SA failed to normalize GH/IGF-I levels in the five patients concerned. In contrast, IGF-I levels normalized very rapidly (5-9 months) in the three patients receiving pegvisomant (10-20 mg/d). CONCLUSION: RT may be an option for the treatment of acromegaly in patients with MCAS when surgery is impossible and SA therapy is ineffective. However, although no bone sarcomatous transformation was observed within the radiation field in this series, this risk cannot be ruled out. As shown in this small series of severely affected patients, pegvisomant therapy may thus be useful to normalize IGF-I levels rapidly.

Acromegalia y cáncer (consecuencias prácticas) / Acromegaly and cancer (practical effects)

La relación entre acromegalia y riesgo incrementado de cáncer se basa en datos derivados de la epidemiología de la acromegalia, la mortalidad del panhipopituitarismo (incluido el déficit de hormona del crecimiento [GH]), los conocimientos sobre riesgo de diversos tumores sólidos en la población general en función de los valores plasmáticos de IGF1, y la información obtenida de diversos modelos experimentales sobre el papel de la GH, los factores de crecimiento y sus proteínas de transporte como reguladores de apoptosis, mitogénesis y proliferación celular.Se presenta un caso clínico de una paciente de 61 años, con historia prolongada de estreñimiento, y diagnosticada de acromegalia 8 años antes; a pesar de la cirugía, la radioterapia y el tratamiento farmacológico con análogos de somatostatina y dopaminérgicos no se ha logrado el control de la enfermedad. Se discute en esta paciente el riesgo de desarrollar cáncer de colon, la posible influencia del mal control de su enfermedad hipofisaria sobre este riesgo, y la estrategia de un seguimiento más adecuado de acuerdo con la información existente en la bibliografía (AU)

Population pharmacodynamic analysis of octreotide in acromegalic patients.

INTRODUCTION: Octreotide is an octapeptide analog of somatostatin used to normalize growth hormone levels in acromegaly. This article presents a population analysis of the relationship between octreotide and growth hormone concentrations in 94 patients with acromegaly, including 10 patients responding incompletely to subcutaneous treatment (poor responders). METHODS: Growth hormone and octreotide concentrations were recorded hourly over 12-hour time periods during long-term subcutaneous treatment. Twelve-hour profiles were also collected on different days up to 2 months after intramuscular injection of the long-acting formulation. We modeled the inhibition of growth hormone secretion by octreotide with a direct maximum inhibition model. A joint analysis of both formulations was performed with NONMEM (GloboMax, LLC, Hanover, Md). During model building, we examined the relationships between parameters and demographic covariates or formulations with the use of likelihood ratio tests. RESULTS: The baseline growth hormone level was higher in poor responders and was best described by a bimodal distribution. The maximum inhibition was common to both formulations and had a mean of 90%, with low interindividual variability. Sensitivity to octreotide (50% inhibitory concentration) was found to be slightly lower on average with intramuscular administration than with subcutaneous administration. CONCLUSION: Given adequate doses of octreotide, in 72% of 94 patients, growth hormone would decrease to levels below 2.5 ng. mL(-1), considered to be a desirable target concentration in acromegaly. This study provides a way to identify poor responders during subcutaneous treatment, allowing an early clinical decision to be made to switch nonresponders to alternative therapies.

Novel somatostatin analogs for the treatment of acromegaly and cancer exhibit improved in vivo stability and distribution.

The biodistribution of several radiolabeled somatostatin (SRIF) analogs was determined in the rat. Newly developed analogs BIM-23190 and BIM-23197 attained higher plasma levels and much greater target tissue concentrations than the clinically used BIM-23014 analog. Highest tissue concentrations of BIM-23190 and BIM-23197 were found in adrenal, kidney, pituitary and pancreas, tissues that are known to be abundant in mRNA for the somatostatin subtype 2 receptor. BIM-23190 and BIM-23197 associated radioactivity in these tissues was prolonged compared with that of BIM-23014, especially in the SRIF-receptor-rich pituitary. BIM-23190 and BIM-23197 were more stable in vivo and much less subject to biliary excretion than BIM-23014. These properties account for the elevated plasma and target tissue concentrations of these new SRIF analogs. Based on higher plasma levels, greater distribution to target tissues and longer in vivo stability, BIM-23190 and BIM-23197 may prove to be superior to BIM-23014 for the treatment of acromegaly and some types of cancer.

Sandostatin LAR in acromegalic patients: long-term treatment.

We have evaluated the long term effects and safety of Sandostatin LAR, a long acting formulation of octreotide, during 18 subsequent injections given every fourth week to 14 octreotide-sensitive acromegalic patients. The dosages (20, 30, or 40 mg) were adjusted according to GH response, side-effects, or symptom relief and assessed on day 28 after each injection. We found a stable and consistent suppression of GH and insulin-like growth factor (IGF-I) during the entire study period. Daily mean GH levels were suppressed below 2 micrograms/L in 9, to between 2-5 micrograms/L in 3, and to between 5-10 micrograms/L in 2 patients. The corresponding IGF-I values were suppressed to below 500 micrograms/L in 9 patients and to between 500-1000 micrograms/L in the remaining 5 patients. Increasing the dosage of Sandostatin LAR from 20 to 30 mg had no obvious additional effect on GH suppression, but provided a further decrease in IGF-I levels. Forty milligrams of the drug had no additional effect on GH or IGF-I compared to 30 mg. Acromegalic signs and symptoms improved during treatment. Although the fluctuations of daily mean octreotide levels were high, dosage increments caused an increase in the average serum concentration in the individual patient. Pituitary tumor size reduction was seen in all previously untreated patients (n = 4). We found only minor changes in glucose metabolism (oral glucose tolerance test and hemoglobin A1C) during treatment, but no biologically relevant changes in thyroid function (TSH, T3, and free T4). One patient developed asymptomatic gallstones, and another acquired vitamin B12 deficiency during treatment. The drug is well tolerated during long term treatment. Sandostatin LAR may well be the future medical treatment of choice for acromegalic patients.