Dopamine receptor subtype 2 expression profile in nonfunctioning pituitary adenomas and in vivo response to cabergoline therapy.

OBJECTIVES: To determine the dopamine receptor subtype 2 (DR2) mRNA levels and protein expression and to evaluate the effect of adjuvant cabergoline therapy on tumour volume (TV) in patients with postoperative residual nonfunctioning pituitary adenoma (NFPA). METHODS: The mRNA expression was quantified by real-time RT-PCR (TaqMan(®)), and protein expression was evaluated by immunohistochemistry. Tumours were classified according to the percentage of immunostained cells for DR2 as scores 1 (<50% of stained cells) or 2 (≥50%). Cabergoline was started at least 6 months after surgery in nine patients with residual tumours (3 mg/week). The cabergoline effect was prospectively evaluated by magnetic resonance imaging using three-dimensional volume calculation. TV reduction >25% was considered significant. RESULTS: The DR2 mRNA expression was variable but was observed in 100% of the samples (N = 20). DR2 protein expression was also observed in all the tumours (N = 34). Twenty-nine tumours (85%) were classified as score 2. The median DR2 mRNA expression was higher in the tumours classified as score 2 compared with score 1 (P = 0·007). TV reduction with cabergoline therapy was observed in 67% of the patients (6/9). The median TV before and after 6 months of treatment was 1·90 cm(3) (0·61-8·74) and 1·69 cm(3) (0·36-4·20) [P = 0·02], respectively. CONCLUSION: In conclusion, DR2 is expressed in all adenomas and the majority of the patients in this study displayed tumour shrinkage on cabergoline (CAB) therapy. Thus, CAB might be useful in adjuvant therapy in NFPA patients with residual tumours after surgery.

Acromegalic patients lost to follow-up: a pilot study.

Approximately 50 % of all acromegalic patients will require lifelong medical treatment to normalize mortality rates and reduce morbidity. Thus, adherence to therapy is essential to achieve treatment goals. To date, no study has evaluated the frequency and reasons for loss to follow-up in the acromegalic population. The current study aimed at evaluating the frequency of acromegalic patient loss to follow-up in three reference centers and the reasons responsible for their low compliance with treatment. All of the files for the acromegalic patients in the three centers were reviewed. Those patients, who had not followed up with the hospital for more than a year, were contacted via phone and/or mail and invited to participate. Patients who agreed to participate were interviewed, and blood samples were collected. A total of 239 files were reviewed; from these 42 patients (17.6 %) were identified who were lost to follow-up. It was possible to contact 27 of these patients, 10 of whom did not attend the appointments for more than one time and 17 of whom agreed to participate in the study. Fifteen of these 17 patients had active disease (88.2 %), and all of the patients restarted treatment in the original centers. The main reason for loss to follow-up was an absence of symptoms. High-quality follow-up is important in acromegaly to successfully achieve the aims of the treatment. An active search for patients may allow the resumption of treatment in a significant proportion of these cases, contributing to reduced morbidity and mortality in this patient population.

Long-term, real-world experience of pasireotide dose reduction in patients with acromegaly.

Pasireotide long-acting release is effective in achieving biochemical control and reducing tumour volume in patients with acromegaly inadequately controlled by first-line therapy. As part of a long-term, real-world study at our centre, 20 of 50 patients receiving pasireotide benefited from a reduction in pasireotide dose. Pasireotide reduced insulin-like growth factor I (IGF-I) levels to below the upper limit of the normal range, with some patients responding within 1-3 months of treatment (n=11) and others after ≥4 months (n=9). Following pasireotide dose reduction, IGF-I levels showed a mild increase but remained within the normal range after a median of 39 months in the early responders and 17 months in the late responders. Glucose and glycated haemoglobin levels decreased following dose reduction. Identifying patients who may benefit from a reduction in pasireotide dose warrants further research as it may improve the management of pasireotide-associated hyperglycaemia in susceptible patients.

Long-term Efficacy and Safety of Pasireotide in Patients With Acromegaly: 14 Years of Single-Center Real-World Experience.

CONTEXT: Acromegaly is a rare, chronic, debilitating disorder caused by prolonged hypersecretion of growth hormone (GH) and overproduction of insulin-like growth factor I (IGF-I). Medical therapies, including the somatostatin receptor ligand (SRL) pasireotide, are frequently used to restore biochemical control. OBJECTIVE: As patients often receive therapy over prolonged periods, long-term data from real-life settings are needed. METHODS: A retrospective analysis was performed using a prospectively maintained database of all patients with acromegaly from our primary care center who were enrolled in clinical studies with pasireotide (first visit November 2008). The main outcome measures were safety and biochemical control (age-adjusted IGF-I ≤ upper limit of normal). RESULTS: Patients (n = 50) entered 4 parental studies and 30 continued in the rollover; at data cutoff (June 2022), 27 were still receiving pasireotide. Overall, median (range) exposure was 58 (3-137) months. Normal IGF-I was achieved in 54%, and acromegaly symptoms and quality of life were improved with treatment. No predictors of pasireotide response were identified; however, controlled patients had smaller tumors and lower GH at baseline. Tumor volume reduction occurred in 63% of evaluable patients (n = 10/16). Most patients presented hyperglycemic events, including 63.2% of patients with normal glucose before treatment. Older patients and those with higher IGF-I, glucose, and HbA1c at baseline had higher glucose and HbA1c during pasireotide treatment. CONCLUSION: Pasireotide provided clinical benefit and was well tolerated for more than 11 years of treatment in acromegaly patients, most of whom were resistant to first-generation SRLs.

Machine Learning-based Prediction Model for Treatment of Acromegaly With First-generation Somatostatin Receptor Ligands.

CONTEXT: Artificial intelligence (AI), in particular machine learning (ML), may be used to deeply analyze biomarkers of response to first-generation somatostatin receptor ligands (fg-SRLs) in the treatment of acromegaly. OBJECTIVE: To develop a prediction model of therapeutic response of acromegaly to fg-SRL. METHODS: Patients with acromegaly not cured by primary surgical treatment and who had adjuvant therapy with fg-SRL for at least 6 months after surgery were included. Patients were considered controlled if they presented growth hormone (GH) <1.0 ng/mL and normal age-adjusted insulin-like growth factor (IGF)-I levels. Six AI models were evaluated: logistic regression, k-nearest neighbor classifier, support vector machine, gradient-boosted classifier, random forest, and multilayer perceptron. The features included in the analysis were age at diagnosis, sex, GH, and IGF-I levels at diagnosis and at pretreatment, somatostatin receptor subtype 2 and 5 (SST2 and SST5) protein expression and cytokeratin granulation pattern (GP). RESULTS: A total of 153 patients were analyzed. Controlled patients were older (P = .002), had lower GH at diagnosis (P = .01), had lower pretreatment GH and IGF-I (P < .001), and more frequently harbored tumors that were densely granulated (P = .014) or highly expressed SST2 (P < .001). The model that performed best was the support vector machine with the features SST2, SST5, GP, sex, age, and pretreatment GH and IGF-I levels. It had an accuracy of 86.3%, positive predictive value of 83.3% and negative predictive value of 87.5%. CONCLUSION: We developed a ML-based prediction model with high accuracy that has the potential to improve medical management of acromegaly, optimize biochemical control, decrease long-term morbidities and mortality, and reduce health services costs.

ZAC1 and SSTR2 are downregulated in non-functioning pituitary adenomas but not in somatotropinomas.

INTRODUCTION: There are few data regarding ZAC1 expression in clinically non-functioning pituitary adenomas (NFPA). Because somatotropinomas and NFPA behave differently with respect to tumor shrinkage during somatostatin analogs (SA) therapy, we sought to compare the ZAC1 and somatostatin receptor (sstr) types 1, 2, 3 and 5 mRNA expression in these two pituitary adenoma subtypes and in normal human pituitaries. METHODS: ZAC1 and SSTR mRNA expression levels were evaluated using real-time RT-PCR (TaqMan) in 20 NFPA and compared with the expression levels in 23 somatotropinomas and five normal pituitaries. The NFPA invasiveness was evaluated using magnetic resonance imaging with Hardy's modified criteria. Ki-67 and p53 were evaluated using immunohistochemistry. RESULTS: A total of 20 patients with NFPA [6 males, median age 56 years (range: 30-78)], 23 with acromegaly [12 males, median age 43 years (range: 24-57)] and five normal pituitaries [4 males, median age 48 years (range: 36-54)] were included. Four of the patients (20%) had Hardy's grade 2 tumors; all of the others had Hardy's grade 3 tumors. The Ki-67 median expression was 2.35 (range: 0.2-9.23), and only four of the tumors (20%) were positive for p53. The ZAC1 mRNA expression was significantly lower in NFPA than in somatotropinomas and in normal pituitaries (p<0.001 for both), as well as the SSTR2 (p=0.001 and 0.01, respectively). The SSTR3 expression was higher in the NFPA than in the somatotropinomas and in the normal pituitaries (p=0.03 and 0.02, respectively). No correlation was found between the ZAC1 mRNA expression and the tumor invasiveness, Ki-67 and p53. CONCLUSION: ZAC1 and SSTR2 are underexpressed and SSTR3 is overexpressed in NFPA compared to those in somatotropinomas and in normal pituitaries, which might explain the lack of tumor shrinkage that is observed in response to commercially available SA therapy in patients with NFPA.