Treatment of acromegaly with the nonpeptide, highly selective somatostatin receptor type 2 agonist paltusotine.

Injectable first-generation somatostatin receptor ligands (fg-SRLs) are the standard of care of medical treatment for acromegaly. While fg-SRLs control acromegaly in up to 50 % of patients, they may lead to bothersome injection pain and site reactions. Paltusotine is an investigational, highly selective somatostatin receptor subtype 2 agonist, which is administered orally once a day. To date, phase 2 and 3 clinical trials suggest paltusotine treatment can achieve biochemical and symptom control in acromegaly, with a safety profile comparable to those of the fg-SRLs. Since paltusotine is a once-daily oral drug, it may represent a future treatment option for addressing patient preference or improving quality of life.

Acromegaly Disease Control Maintained After Switching From Injected Somatostatin Receptor Ligands to Oral Paltusotine.

CONTEXT: Paltusotine is a nonpeptide selective somatostatin receptor 2 agonist in development as once-daily oral treatment for acromegaly. OBJECTIVE: To evaluate the efficacy and safety of paltusotine in the treatment of patients with acromegaly previously controlled with injected somatostatin receptor ligands (SRLs). METHODS: This phase 3, randomized, double-blind, placebo-controlled trial enrolled adults with acromegaly who had insulin-like growth factor I (IGF-I) ≤1.0 times the upper limit of normal (×ULN) while receiving a stable dose of depot octreotide or lanreotide. Patients were switched from injected SRLs and randomized to receive paltusotine or placebo orally for 36 weeks. The primary endpoint was proportion of patients maintaining IGF-I ≤1.0×ULN. Secondary endpoints were change in IGF-I level, change in Acromegaly Symptom Diary (ASD) score, and maintenance of mean 5-sample growth hormone (GH) <1.0 ng/mL. RESULTS: The primary endpoint was met: 83.3% (25/30) of patients receiving paltusotine and 3.6% (1/28) receiving placebo maintained IGF-I ≤1.0×ULN (odds ratio: 126.53; 95% CI: 13.73, >999.99; P<.0001). Paltusotine was also superior to placebo for all secondary endpoints: mean (±SE) change in IGF-I of 0.04±0.09×ULN versus 0.83±0.1×ULN (P<.0001); mean (±SE) change in ASD score of -0.6±1.5 versus 4.6±1.6 (P=.02); mean GH maintained at <1.0 ng/mL in 20/23 (87.0%) versus 5/18 (27.8%) patients (odds ratio: 16.61; 95% CI: 2.86, 181.36; P=.0003). The most common adverse events were acromegaly symptoms and gastrointestinal effects characteristic of SRLs. CONCLUSION: Replacement of injected SRLs by once-daily oral paltusotine was effective in maintaining both biochemical and symptom control in patients with acromegaly and was well tolerated.

Skeletal Muscle Evaluation in Patients With Acromegaly.

Context: Patients with acromegaly are characterized by chronic exposure to high growth hormone (GH) and insulin-like growth factor-1 levels, known for their anabolic effect on skeletal muscle. Therefore, an increased skeletal muscle mass could be hypothesized in these individuals. Herein, we have performed a systematic revision of published evidence regarding skeletal muscle mass, quality, and performance in patients with acromegaly. Evidence Acquisition: A systematic review of the literature in the PubMed database up to September 1, 2023, was conducted with the following query: acromegaly AND ("muscle mass" OR "skeletal muscle"). We excluded studies that did not compare different disease states or used nonradiological methods for the skeletal muscle analyses, except for bioelectrical impedance analysis. Evidence Synthesis: Fifteen studies met the inclusion criteria. A total of 360 patients were evaluated for skeletal muscle mass, 122 for muscle fatty atrophy, and 192 for muscle performance. No clear evidence of increased skeletal muscle mass in patients with active disease compared to control or healthy individuals emerged. As for skeletal muscle quality, we observed a trend toward higher fatty infiltration among patients with acromegaly compared to healthy participants. Likewise, patients with active disease showed consistently worse physical performance compared to control or healthy individuals. Conclusion: Skeletal muscle in acromegaly has lower quality and performance compared to that of healthy individuals. The small number of published studies and multiple confounding factors (eg, use of different radiological techniques) contributed to mixed results, especially regarding skeletal muscle mass. Well-designed prospective studies are needed to investigate skeletal muscle mass in patients with acromegaly.

Epigenetic control of adamantinomatous craniopharyngiomas.

INTRODUCTION: Studies addressing the methylation pattern in adamantinomatous craniopharyngioma (ACP) are lacking. OBJECTIVE: To identify methylation signatures in ACPs regarding clinical presentation and outcome. METHODS: Clinical and pathology data were collected from 35 ACP patients (54% male; 18.1 years [2-68]). CTNNB1 mutations and methylation profile (MethylationEPIC/Array-Illumina) were analyzed in tumoral DNA. Unsupervised machine learning analysis of this comprehensive methylome sample was achieved using hierarchical clustering and multi-dimensional scaling. Statistical associations between clusters and clinical features were achieved using Fisher's test and global biological process interpretations were aided by Gene Ontology enrichment analyses. RESULTS: Two clusters were revealed consistently by all unsupervised methods (ACP-1: n = 18; ACP-2: n = 17) with strong bootstrap statistical support. ACP-2 was enriched by CTNNB1 mutations (100% vs 56%, P = 0.0006), hypomethylated in CpG Island (CGI), non-CGI sites, and globally (P < 0.001), and associated with greater tumor size (24.1 vs 9.5cm3, P = 0.04). Enrichment analysis highlighted pathways on signaling transduction, transmembrane receptor, development of anatomical structures, cell-adhesion, cytoskeleton organization, and cytokine binding, and also cell-type specific biological processes as regulation of oligodendrocytes, keratinocyte, and epithelial cells differentiation. CONCLUSION: Two clusters of ACP patients were consistently revealed by unsupervised machine learning methods, being one of them significantly hypomethylated, enriched by CTNNB1 mutated ACPs, and associated with increased tumor size. Enrichment analysis reinforced pathways involved in tumor proliferation and in cell-specific tumoral microenvironment.

Diffusion-weighted imaging does not seem to be a predictor of consistency in pituitary adenomas.

PURPOSE: To prospectively evaluate the usefulness of T1-weighted imaging (T1WI) and diffusion-weighted imaging (DWI) sequences in predicting the consistency of macroadenomas. In addition, to determine their values ​​as prognostic factors of surgical outcomes. METHODS: Patients with pituitary macroadenoma and surgical indication were included. All patients underwent pre-surgical magnetic resonance imaging (MRI) that included the sequences T1WI before and after contrast administration and DWI with the apparent diffusion coefficient (ADC) map. Post-surgical MRI was performed at least 3 months after surgery. The consistency of the macroadenomas was evaluated at surgery, and they were grouped into soft and intermediate/hard adenomas. Mean ADC values, signal on T1WI and the ratio of tumor ADC values ​​to pons (ADCR) were compared with tumor consistency and grade of surgical resection. RESULTS: A total of 80 patients were included. A softened consistency was found at surgery in 53 patients and hardened in 27 patients. The median ADC in the soft consistency group was 0.532 × 10-3 mm2/sec (0.306 - 1.096 × 10-3 mm2/sec), and in the intermediate/hard consistency group was 0.509 × 10-3 mm2/sec (0.308 - 0.818 × 10-3 mm2/sec). There was no significant difference between the median values ​​of ADC, ADCR and signal on T1W between the soft and hard tumor groups, or between patients with and without tumor residue. CONCLUSION: Our results did not show usefulness of the DWI and T1WI for assessing the consistency of pituitary macroadenomas, nor as a predictor of the degree of surgical resection.

Biomarkers of response to treatment in acromegaly.

INTRODUCTION: Medical treatment of acromegaly is based in a `trial and error` approach. First-generation somatostatin receptor ligands (fg-SRL) are prescribed as first-line medical therapy to the vast majority of patients, despite lack of disease control in approximately 60% of patients. However, other drugs used in acromegaly treatment are available (cabergoline, pasireotide and pegvisomant). AREAS COVERED: In this article, we review and discuss the biomarkers of response to medical treatment in acromegaly. EXPERT OPINION: Biomarkers for fg-SRL that can already be applied in clinical practice are: gender, age, pretreatment GH and IGF-I levels, cytokeratin granulation pattern, and the expression of somatostatin receptor type 2. Using biomarkers of response could guide treatment towards precision medicine with greater efficacy and lower costs.

New Treatments for Acromegaly in Development.

Acromegaly treatment has greatly evolved in recent decades, but there are still patients whose acromegaly is not controlled with currently available treatments, and there is a need to improve the treatment burden. Fortunately, there are new treatments under development that may increase treatment efficacy and convenience.

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.

Refractory somatotroph adenomas.

Somatotroph adenomas are usually controlled with standard therapy, which can include surgery, medical treatment and radiotherapy. Some tumors have a more aggressive behavior and are refractory to standard therapy. In this review, we summarize the phenotype of these tumors and the current options for their management.

miR-383-5p, miR-181a-5p, and miR-181b-5p as Predictors of Response to First-Generation Somatostatin Receptor Ligands in Acromegaly.

Acromegaly is a chronic systemic disease caused in the vast majority of cases by growth hormone (GH)-secreting adenoma, with surgery being the first-line treatment. When a cure is not attained with surgery, first-generation somatostatin receptor ligands (fg-SRLs) are the most common medication prescribed. Predictors of response to fg-SRLs have been studied; however, they cannot fully predict the response to fg-SRL. MicroRNAs are small RNAs, the main role of which is messenger RNA (mRNA) post-transcriptional regulation. This study aimed to identify the microRNAs involved in resistance to treatment with fg-SRLs in acromegaly. Ten patients with acromegaly undergoing treatment with fg-SRLs were selected to undergo miRNA sequencing: five controlled and five uncontrolled with treatment. Bioinformatic analysis was performed to detect differentially expressed miRNAs. Then, the same 10 samples were used for validation by qPCR and an additional 22 samples were analyzed, totaling 32 samples. e We found 59 differentially expressed miRNAs in the first analysis. miR-181a-5p and miR-181b-5p were downregulated, and miR-383-5p was upregulated in the uncontrolled group. Receiver operating characteristic (ROC) curve analysis of miR-383-5p showed an NPV of 84.3% and a PPV of 84.5%. In summary, miR-181a-5p, miR-181b-5p, and miR-383-5p are biomarkers of response to fg-SRLs, and they can be used individually or included in prediction models as tools to guide clinical decisions.

ACROBAT Edge: Safety and Efficacy of Switching Injected SRLs to Oral Paltusotine in Patients With Acromegaly.

CONTEXT: Paltusotine is a once-daily, oral, nonpeptide small-molecule somatostatin receptor type 2 (SST2) agonist in clinical development for treatment of acromegaly. OBJECTIVE: This work aimed to evaluate change in insulin-like growth factor I (IGF-I) levels in patients switched from octreotide long-acting release or lanreotide depot monotherapy to paltusotine. METHODS: A phase 2, open-label, prospective, multicenter, multinational, nonrandomized, single-arm exploratory study was conducted in which dosage uptitrations were performed in a double-blinded manner. At 26 global sites, patients with acromegaly switched to paltusotine from injected somatostatin receptor ligand (SRL)-based therapy. Patients received 13-week treatment with once-daily oral paltusotine (10-40 mg/d). The primary end point was change from baseline to week 13 in IGF-I for patients who switched from long-acting octreotide or lanreotide depot monotherapy to paltusotine (group 1). All patients underwent a 4-week paltusotine washout at end of treatment period (wk 13-17). IGF-I, growth hormone (GH), patient-reported outcome, and safety data were collected. RESULTS: Forty-seven patients enrolled. In group 1 (n = 25), IGF-I and GH showed no significant change between SRL baseline and end of paltusotine treatment at week 13 (median change in IGF-I = -0.03×upper limit of normal [ULN]; P = .6285; GH = -0.05 ng/mL; P = .6285). IGF-I and GH rose significantly in the 4 weeks after withdrawing paltusotine (median change in IGF-I = 0.55×ULN; P < .0001 [median increase 39%]; GH = 0.72 ng/mL; P < .0001 [109.1% increase]). No patients discontinued because of adverse events (AE); no treatment-related serious AEs were reported. CONCLUSION: These results suggest once-daily oral paltusotine was effective in maintaining IGF-I values in patients with acromegaly who switched from injected SRLs. Paltusotine was well tolerated with a safety profile consistent with other SRLs.

Characterization of sporadic somatotropinomas with high GIP receptor expression.

PURPOSE: To analyze the expression of glucose-dependent insulinotropic polypeptide receptor (GIPR) in somatotropinomas specimens and compare clinical, biochemical, radiological, therapeutic, molecular, and pathological data among those who overexpressed (GIPR +) and those who did not overexpress (GIPR - ) GIPR. METHODS: Clinical, biochemical, radiological, molecular, and pathological data were collected. GNAS1 sequencing was performed with the Sanger method. Protein expression of somatostatin receptor subtypes 2 and 5 and CAM 5.2 were analyzed by immunohistochemistry. Quantitative real-time PCR was performed to analyze the mRNA expression of GIPR with the TaqMan® method. Positive expression was considered when the fold change (FC) was above 17.2 (GIPR +). RESULTS: A total of 74 patients (54% female) were included. Eighteen tumors (24%) were GIPR + . Gsp mutation was detected in 30 tumors (40%). GIPR + tumors were more frequently densely granulated adenomas (83% vs 47%, p = 0.028). There was no difference in clinical, biochemical, radiological, therapeutic (surgical cure or response to medical therapy), or other pathological features between GIPR + and GIPR -  tumors. Twenty-eight out of 56 (50%) GIPR -  tumors harbored a gsp mutation, whereas two out of 18 (11%) GIPR + tumors harbored a gsp mutation (p = 0.005). CONCLUSION: We described, for the first time, that GIPR + and gsp mutations are not mutually exclusive, but gsp mutations are less common in GIPR + tumors. GIPR + and GIPR -  tumors have similar clinical, biochemical, radiological, therapeutic, and pathological features, with the exception of a high frequency of densely granulated adenomas among GIPR + tumors.

TP53 mutations in functional corticotroph tumors are linked to invasion and worse clinical outcome.

Corticotroph macroadenomas are rare but difficult to manage intracranial neoplasms. Mutations in the two Cushing's disease mutational hotspots USP8 and USP48 are less frequent in corticotroph macroadenomas and invasive tumors. There is evidence that TP53 mutations are not as rare as previously thought in these tumors. The aim of this study was to determine the prevalence of TP53 mutations in corticotroph tumors, with emphasis on macroadenomas, and their possible association with clinical and tumor characteristics. To this end, the entire TP53 coding region was sequenced in 86 functional corticotroph tumors (61 USP8 wild type; 66 macroadenomas) and the clinical characteristics of patients with TP53 mutant tumors were compared with TP53/USP8 wild type and USP8 mutant tumors. We found pathogenic TP53 variants in 9 corticotroph tumors (all macroadenomas and USP8 wild type). TP53 mutant tumors represented 14% of all functional corticotroph macroadenomas and 24% of all invasive tumors, were significantly larger and invasive, and had higher Ki67 indices and Knosp grades compared to wild type tumors. Patients with TP53 mutant tumors had undergone more therapeutic interventions, including radiation and bilateral adrenalectomy. In conclusion, pathogenic TP53 variants are more frequent than expected, representing a relevant amount of functional corticotroph macroadenomas and invasive tumors. TP53 mutations associated with more aggressive tumor features and difficult to manage disease.

MicroRNA in Acromegaly: Involvement in the Pathogenesis and in the Response to First-Generation Somatostatin Receptor Ligands.

Acromegaly is a chronic and systemic disease due to excessive growth hormone and insulin-like growth factor type I caused, in the vast majority of cases, by a GH-secreting pituitary adenoma. About 40% of these tumors have somatic mutations in the stimulatory G protein alpha-subunit 1 gene. The pathogenesis of the remaining tumors, however, is still not fully comprehended. Surgery is the first-line therapy for these tumors, and first-generation somatostatin receptor ligands (fg-SRL) are the most prescribed medications in patients who are not cured by surgery. MicroRNAs are small, non-coding RNAs that control the translation of many mRNAs, and are involved in the post-transcriptional regulation of gene expression. Differentially expressed miRNAs can explain differences in the pathogenesis of acromegaly and tumor resistance. In this review, we focus on the most validated miRNAs, which are mainly involved in acromegaly's tumorigenesis and fg-SRL resistance, as well as in circulating miRNAs in acromegaly.

Acromegaly and Colorectal Neoplasm: An Update.

Acromegaly is a systemic disease caused by excessive inappropriate secretion of GH and IGF-I levels, resulting in many systemic complications, including cardiovascular, respiratory, metabolic diseases, and a possible increased risk of some neoplasias. Although many studies on acromegaly and cancer remain uncertain, most data indicate that colorectal cancer (CRC) incidence is increased in this population. The exact mechanism involved in the role of GH-IGF-I axis in CRC has not been fully explained, yet it is associated with local and circulating effects of GH and IGF-I on the colon, promoting angiogenesis, cell proliferation, risk of mutation, inhibition of tumor-suppressor genes and apoptosis, thus facilitating a tumor microenvironment. Nevertheless, population-based studies present controversial findings on CRC incidence and mortality. All worldwide guidelines and expert consensuses agree with the need for colonoscopic screening and surveillance in acromegaly, although there is no consensus regarding the best period to do this. This review aims to analyze the existing data on CRC and acromegaly, exploring its pathophysiology, epidemiological studies and their limitations, colonic polyp characteristics, overall cancer and CRC incidences and mortality, risk factors for colon cancer pathophysiology, and recommendation guideline aspects.

Innovative therapeutics in acromegaly.

Acromegaly is a systemic disease associated with increased morbidity and mortality that can be prevented with adequate disease control. Three modalities of treatment (surgery, medical treatment, and radiotherapy) are available; however, a significant proportion of patients still maintain disease activity despite treatment. Therefore, there is a need for innovations in the treatment of acromegaly that include changes in the current trial and error approach and the development of new drugs. In this review, we summarize the recent innovations in the treatment of acromegaly and address the future perspectives in this field.

Pituitary acting drugs: cabergoline and pasireotide.

First-line treatment for Cushing´s disease is transsphenoidal surgery. But in cases of persistent or recurrent disease after surgery, contraindications to surgery, severe hypercortisolism control before surgery, or for patients waiting for radiotherapy effects, medical therapy may be indicated. Pituitary-directed agents include cabergoline and pasireotide. Both drugs present similar potential for biochemical control and pasireotide has additionally been proved to reduce tumor volume. Moreover, pasireotide was evaluated in high quality studies. In respect to safety, both drugs are well tolerated and safe, but special attention should be given for cardiac valve disease and psychiatric disorder for cabergoline, and hyperglycemia for pasireotide.

Telomere length and Wnt/ß-catenin pathway in adamantinomatous craniopharyngiomas.

Objectives: To evaluate how telomere length behaves in adamantinomtous craniopharyngioma (aCP) and if it contributes to the pathogenesis of aCPs with and without CTNNB1 mutations. Design: Retrospective cross-sectional study enrolling 42 aCP patients from 2 tertiary institutions. Methods: Clinicopathological features were retrieved from the patient's charts. Fresh frozen tumors were used for RNA and DNA analyses. Telomere length was evaluated by qPCR (T/S ratio). Somatic mutations in TERT promoter (TERTp) and CTNNB1 were detected by Sanger and/or whole-exome sequencing. We performed RNA-Seq to identify differentially expressed genes in aCPs presenting with shorter or longer telomere lengths. Results: Mutations in CTNNB1 were detected in 29 (69%) tumors. There was higher frequency of CTNNB1 mutations in aCPs from patients diagnosed under the age of 15 years (85% vs 15%; P = 0.04) and a trend to recurrent disease (76% vs 24%; P = 0.1). No mutation was detected in the TERTp region. The telomeres were shorter in CTNNB1-mutated aCPs (0.441, IQR: 0.297-0.597vs 0.607, IQR: 0.445-0.778; P = 0.04), but it was neither associated with clinicopathological features nor with recurrence. RNAseq identified a total of 387 differentially expressed genes, generating two clusters, being one enriched for short telomeres and CTNNB1-mutated aCPs. Conclusions: CTNNB1: mutations are more frequent in children and adolescents and appear to associate with progressive disease. CTNNB1-mutated aCPs have shorter telomeres, demonstrating a relationship between the Wnt/ß-catenin pathway and telomere biology in the pathogenesis of aCPs.