Teste agudo com octreotide subcutâneo como preditor de resposta ao tratamento com octreotide LAR®

Abstract

RESUMOOs análogos da somatostatina são muito utilizados no tratamento da acromegalia. Com o objetivo de determinar o valor do teste agudo (TA) com octreotide subcutâneo (SC) como preditor da resposta ao tratamento com octreotide LAR ® , analisamos os dados de 20 pacientes. Para o TA, amostras de sangue foram colhidas antes e duas horas após a administração de octreotide SC para a dosagem de GH. Os níveis de GH antes e após o TA foram 21,9 (2,3-143,4) e 3,1ng/mL (0,3-61,3), respectivamente. Foi considerado controle de doença: GH< 2,5ng/mL e IGF-I normal em algum momento durante o tratamento. A sensibilidade, especificidade e os valores preditivos positivo e negativo do TA foram 0,9, 0,6, 0,69 e 0,86 para redução de 75% do GH no teste. Concluímos que, em nossa casuística, um decréscimo de 75% dos níveis de GH no TA teve um bom poder discriminatório entre pacientes com maior e menor chance de resposta ao tratamento. ABSTRACT Acute Test With Subcutaneous Octreotide as a Predictor of the Response to Treatment With Octreotide LAR ® .Somatostatin analogues are frequently used to treat acromegaly. To determine the value of the acute test (AT) with subcutaneous (SC) octreotide as a predictor of the response to treatment with octreotide LAR ® , we analyzed data from 20 patients. For the AT, blood was drawn before and two hours after the SC administration of octreotide for measuring GH. GH levels before and after the AT were 21.9ng/mL (2.3-143.4) and 3.1ng/mL (0.3-61.3), respectively. Control of the disease was defined as: GH< 2.5ng/mL and normal IGF-I anytime during treatment. Sensitivity, specificity, positive and negative predictive values of the AT were 0.9, 0.6, 0.69 and 0.86 for a reduction of 75% of the GH on the test. From our sample we conclude that a 75% reduction of the GH levels during the acute test was able to discriminate patients with a higher or lower chance of responding to treatment.

Somatostatin receptors subtypes 2 and 5, dopamine receptor type 2 expression and gsp status as predictors of octreotide LAR® responsiveness in acromegaly

“…A positive GH response in this test was defined as >75% decrease of the GH levels. Sensitivity, specifi city, positive and negative predictive values of the acute test were respectively 0.90, 0.60, 0.69 and 0.86 for a reduction of 75% of the GH on the test (14).…”

“…Also, attaining GH levels below 5 ng/mL after 3 months and IGF-I levels below 550 ng/mL after 6 months of SA treatment appear to be good positive predictors of long term control (6). GH suppression test, following a single subcutaneous injection of octreotide (acute test), has been extensively studied with variable results (7)(8)(9)(10)(11)(12)(13)(14). Scintilography with 111In-pentetreotide (Octreoscan) has also been studied, with limited success at predicting SA-mediated disease control (8,15,16).…”

Etiologic aspects and management of acromegaly

“…Therefore, the ability to predict which patients will achieve "safe" GH levels and IGF-I normalization would be advantageous. The usefulness of the acute test with subcutaneous octreotide has been extensively investigated (56)(57)(58)(59)(60)(61)(62)(63) and even intravenous octreotide has been used for this purpose (64). A positive response is considered when GH levels fall at least 50%.…”