A novel somatostatin receptor ligand for human ACTH - and GH -secreting pituitary adenomas.

OBJECTIVE: Somatostatin receptor ligands have come to play a pivotal role in the treatment of both ACTH- and GH-secreting pituitary adenomas. Clinical efficacy averages 30-50%, thus a considerable number of patients with Cushing's disease or acromegaly remain unresponsive to this therapeutic approach. HTL0030310 is a new somatostatin receptor ligand selective for subtype 5 over subtype 2, thus with a different receptor profile compared to clinical somatostatin receptor ligands. DESIGN: Assessment of the effect of HTL0030310 on hormone secretion in human ACTH- and GH-secreting pituitary adenomas in vitro. METHODS: Primary cultures from 3 ACTH-secreting and 5 GH-secreting pituitary adenomas were treated with 1, 10 and 100 nM HTL0030310 alone or with 10 nM CRH or GHRH, respectively. Parallel incubations with 10 nM pasireotide were also carried out. ACTH and GH secretion were assessed after 4 and 24 hour incubation; SSTR2, SSTR3, SSTR5, GH and POMC expression were evaluated after 24 hours. RESULTS: HTL0030310 reduced unchallenged ACTH and POMC levels up to 50% in 2 ACTH-secreting adenomas and blunted CRH-stimulated ACTH/POMC by 20-70% in all 3 specimens. A reduction in spontaneous GH secretion was observed in 4 GH-secreting adenomas and in 2 specimens during GHRH co-incubation. SSTRs expression was detected in all specimens. CONCLUSIONS: This first study on a novel somatostatin receptor 5-preferring ligand indicates that HTL0030310 can inhibit hormonal secretion in human ACTH- and GH-secreting pituitary adenomas. These findings suggest a potential new avenue for somatostatin ligands in the treatment of Cushing's disease and acromegaly.

Modern approach to resistant acromegaly.

BACKGROUND: Targets of acromegaly treatment are normalization of biochemical values, removal/reduction/stabilization of the pituitary mass, control of clinical activity and mortality with a multimodal/multidisciplinary approach. Despite significant technological and pharmacological progress, still several patients with acromegaly bear a resistant somatotroph adenoma and active disease may persist for many years with resultant poor clinical outcomes. AIM: To review briefly definition and pathophysiology of resistance to acromegaly treatment and the options of medical treatment in this context, exploring the role of novel clinical and molecular biomarkers in the personalization of therapy and proposing updates to the currently available guidelines for the treatment of resistant GH-secreting adenomas. CONCLUSIONS: In the last few years, in parallel with the increased number of medical options available for the therapy of acromegaly, relevant advances occurred in the understanding of the role of novel molecular and clinical biomarkers in predicting the responsiveness to second-line medical treatments, such as Pegvisomant and Pasireotide LAR, and helping clinicians in the personalization of the follow-up and treatment of resistant somatotroph adenomas. The integration of these findings into the existing guidelines may represent a possibly important step forward in the management of "difficult" acromegaly patients.

Predictive Factors of Somatostatin Receptor Ligand Response in Acromegaly-A Prospective Study.

CONTEXT: Somatostatin receptor ligands (SRLs) are the cornerstone medical treatments for acromegaly; however, many patients remain unresponsive to SRLs. Well-established predictive markers of response are needed. OBJECTIVE: We aimed to explore the relationship between responsiveness to SRLs relative to somatostatin (SST)2A and 5 receptor expression, adenoma granularity, and T2-weighted magnetic resonance imaging (MRI) signal intensity (T2WSI). METHODS: We conducted a multicentric, prospective, observational cohort study, in France. Forty-nine naïve patients (ie, patients without preoperative SRL treatment) with active acromegaly following surgery were treated with octreotide (group 1; n = 47), or pasireotide if uncontrolled under first-generation SRLs (group 2; n = 9). Data were collected at baseline and months 3 and 6. Biochemical measurements, immunohistochemistry studies, and MRI readings were centralized. RESULTS: In group 1, IGF-I decrease from baseline to month 6 positively correlated with SST2A immunoreactive score (IRS), P = 0.01. Densely granulated/intermediate adenomas had a greater IGF-I and GH decrease under octreotide compared with sparsely granulated adenomas (P = 0.02 and P = 0.006, respectively), and expressed greater levels of SST2A (P < 0.001), coupled with lower levels of SST5 (P = 0.004). T2WSI changed between preoperative MRI and month 6 MRI in one-half of the patients. Finally, SST5 IRS was higher in preoperative hyperintense compared with preoperative hypointense adenomas (P = 0.04), and most sparsely granulated and most hyperintense adenomas expressed high SST5 levels. CONCLUSION: We prospectively confirm that SST2A and adenoma granularity are good predictors of response to octreotide. We propose the IRS for scoring system harmonization. MRI sequences must be optimized to be able to use the T2WSI as a predictor of treatment response.

Persistent remission of acromegaly in a patient with GH-secreting pituitary adenoma: Effect of treatment with pasireotide long-acting release and consequence of treatment withdrawal.

WHAT IS KNOWN AND OBJECTIVE: Somatostatin analogues (SSAs) have been used for the treatment of acromegaly for several decades. However, a unified conclusion on the duration of SSAs therapy or the possibility of medication withdrawal is still missing. We aimed to report a case of acromegaly cured by pasireotide long-acting release (PAS-LAR) and provide some information on the withdrawal of SSAs after stable regression in acromegalic patients. CASE SUMMARY: A 55-year-old male patient, who was diagnosed with acromegaly and refused surgery and received PAS-LAR as initial treatment, had maintained stability for ten years under the regular treatment with PAS-LAR. The pituitary microadenoma was also decreased during the treatment. After the PAS-LAR discontinuation for 21 months, no evidence of biochemical or clinical recurrence was found in this patient. WHAT IS NEW AND CONCLUSION: The use of PAS-LAR in a subset of naive-treatment patients is promising to induce long-term regression. A subgroup of patients with mild and well-controlled acromegaly might hope for perpetual remission after the withdrawal of medication.

Differences in somatostatin receptor subtype expression in patients with acromegaly: new directions for targeted therapy?

PURPOSE: To analyze the expression of somatostatin receptor (SSTR)2a and 5 by immunohistochemistry (IHC) in surgically resected somatotrophic pituitary adenomas and to associate expression rates with tumor size and clinical, biochemical, and histological parameters and response to somatostatin analog (SA) therapy. METHODS: Forty-three microsurgically treated patients with histopathologically proven growth hormone (GH)-producing pituitary adenoma were included (WHO 2017). SSTR subtype expression was analyzed in adenoma tissues using monoclonal antibodies (Abcam, SSTR2a-UMB1, SSTR5-UMB4). Expression rates were classified as low (≤ 20% staining positivity), moderate (21-50%), and high (> 50%). Furthermore, biochemical parameters such as human growth hormone (hGH) and insulin-like growth factor-1 (IGF-1) levels were measured and clinical, biochemical, radiological, and histological data were evaluated. RESULTS: Of the 43 patients included in this study, 28 were female and 15 were male. The median age was 52 years (range 17-72 years). The median tumor size was 1.2 cm (range: 0.13-3.93 cm). All resected tumors showed positivity for somatotrophic hormone (STH). In all tissue samples, SSTR2a signal expression was detectable in immunohistochemistry, while only 39 samples were positive for SSTR5. Thirty-six samples had a high expression of SSTR2a, while three had a moderate and four a low SSTR2a signal. In comparison, SSTR5 signal was high in 26 out of 43 samples, while seven adenomas showed a moderate and six cases a low expression rate of SSTR5. The median IGF-1 was 714.2 µg/l and the median GH 19.6 mU/l (= 6.53 µg/l). The present study indicates that there is no significant relationship between the expression rates of receptor subtypes and the parameters we analyzed. However, our study revealed that smaller adenomas have a lower baseline GH level (p = 0.015), CONCLUSION: IHC with monoclonal antibodies appears to be a suitable method to determine the expression rates of SSTR2a and 5 at protein levels, as it is not possible to draw conclusions regarding receptor subtypes solely on the basis of the parameters analyzed.

The Future of Somatostatin Receptor Ligands in Acromegaly.

Currently, the first-generation somatostatin receptor ligands (fg-SRLs), octreotide LAR and lanreotide autogel, are the mainstays of acromegaly treatment and achieve biochemical control in approximately 40% of patients and tumor shrinkage in over 60% of patients. Pasireotide, a second-generation SRL, shows higher efficacy with respect to both biochemical control and tumor shrinkage but has a worse safety profile. In this review, we discuss the future perspectives of currently available SRLs, focusing on the use of biomarkers of response and precision medicine, new formulations of these SRLs and new drugs, which are under development. Precision medicine, which is based on biomarkers of response to treatment, will help guide the decision-making process by allowing physicians to choose the appropriate drug for each patient and improving response rates. New formulations of available SRLs, such as oral, subcutaneous depot, and nasal octreotide, may improve patients' adherence to treatment and quality of life since there will be more options available that better suit each patient. Finally, new drugs, such as paltusotine, somatropin, ONO-5788, and ONO-ST-468, may improve treatment adherence and present higher efficacy than currently available drugs.

More than a decade of real-world experience of pegvisomant for acromegaly: ACROSTUDY.

OBJECTIVE: To report the final long-term safety and efficacy analyses of patients with acromegaly treated with pegvisomant from the ACROSTUDY. DESIGN: Global (15 countries), multicentre, non-interventional study (2004-2017). METHODS: The complete ACROSTUDY cohort comprised patients with acromegaly, who were being treated with pegvisomant (PEGV) prior to the study or at enrolment. The main endpoints were long-term safety (comorbidities, adverse events (AEs), pituitary tumour volumes, liver tests) and efficacy (IGF1 changes). RESULTS: Patients (n = 2221) were treated with PEGV for a median of 9.3 years (range, 0-20.8 years) and followed up for a median of 7.4 years (range, 0-13.9 years). Before PEGV, 96.3% had received other acromegaly treatments (surgery/radiotherapy/medications). Before PEGV treatment, 87.2% of patients reported comorbidities. During ACROSTUDY, 5567 AEs were reported in 56.5% of patients and of these 613 were considered treatment-related (in 16.5% of patients) and led to drug withdrawal in 1.3%. Pituitary imaging showed a tumour size increase in 7.1% of patients; the majority (71.1%) reported no changes. Abnormal AST or ALT liver tests occurred in 3.2% of patients. IGF1 normalization rate improved over time, increasing from 11.4% at PEGV start to 53.7% at year 1, and reaching 75.4% at year 10 with the use of ≥30 mg PEGV/day in an increasing proportion of patients. CONCLUSION: This comprehensive review of the complete cohort in ACROSTUDY confirmed the overall favourable benefit-to-risk profile and high efficacy of PEGV as mono- and combination therapy in patients with an aggressive course/uncontrolled/active acromegaly requiring long-term medical therapy for control.

Pasireotide in the Personalized Treatment of Acromegaly.

The delay in controlling the disease in patients who do not respond to first-line treatment with first generation somatostatin receptor ligands (first-generation SRLs) can be quantified in years, as every modification in the medical therapy requires some months to be fully evaluated. Considering this, acromegaly treatment should benefit from personalized medicine therapeutic approach by using biomarkers identifying drug response. Pasireotide has been positioned mostly as a compound to be used in first-generation SRLs resistant patients and after surgical failure, but sufficient data are now available to indicate it is a first line therapy for patients with certain characteristics. Pasireotide has been proved to be useful in patients in which hyperintensity T2 MRI signal is shown and in those depicting low SST2 and high expression of SST5, low or mutated AIP condition and sparsely granulated immunohistochemical pattern. This combination of clinical and pathological characteristics is unique for certain patients and seems to cluster in the same cases, strongly suggesting an etiopathogenic link. Thus, in this paper we propose to include this clinico-pathologic phenotype in the therapeutic algorithm, which would allow us to use as first line medical treatment those compounds with the highest potential for achieving the fastest control of GH hypersecretion as well as a positive effect upon tumor shrinkage, therefore accelerating the implementation of precision medicine for acromegaly. Moreover, we suggest the development, validation and clinical use of a pasireotide acute test, able to identify patients responsive to pasireotide LAR as the acute octreotide test is able to do for SRLs.

Epithelial-Mesenchymal Transition in the Resistance to Somatostatin Receptor Ligands in Acromegaly.

Epithelial-mesenchymal transition (EMT) is a dynamic process by which epithelial cells loss their phenotype and acquire mesenchymal traits, including increased migratory and invasive capacities. EMT is involved in physiological processes, such as embryogenesis and wound healing, and in pathological processes such as cancer, playing a pivotal role in tumor progression and metastasis. Pituitary tumors, although typically benign, can be locally invasive. Different studies have shown the association of EMT with increased tumor size and invasion in pituitary tumors, and in particular with a poor response to Somatostatin Receptor Ligands (SRLs) treatment in GH-producing pituitary tumors, the main cause of acromegaly. This review will summarize the current knowledge regarding EMT and SRLs resistance in acromegaly and, based on this relation, will suggest new biomarkers and possible therapies to SRLs resistant tumors.

MANAGEMENT OF ENDOCRINE DISEASE: Etiology and outcome of acromegaly in patients with a paradoxical GH response to glucose.

To gain more insight on the pathogenesis of somatotroph pituitary adenomas, recent studies have focused on a subgroup of patients with acromegaly displaying a paradoxical growth hormone (GH) response during oral glucose tolerance test (OGTT). The paradoxical rise of GH after oral glucose intake occurs in about one-third of acromegaly patients and has been pathogenetically linked, by analogy to glucose-dependent insulinotropic polypeptide (GIP)-dependent Cushing's syndrome, to the ectopic expression of GIP receptor (GIPR) in somatotroph adenoma cells. GIPR-expressing adenomas are negative for activating GNAS gene mutations and display distinct cytogenetic and DNA methylation profiles, highlighting their unique molecular pathogenesis. Acromegaly patients with a paradoxical GH response pattern seem to display higher insulin-like growth factor-1 (IGF-1) concentrations and harbour smaller adenomas that are more often of the densely granulated phenotype. They seem also to show a better response to somatostatin receptor ligands. In addition, persistent paradoxical GH response after surgery may be a biological marker of the residual disease postoperatively. Targeted therapy to antagonize GIP receptor on GIPR-expressing somatotroph adenomas could be a new treatment approach for acromegaly patients with a paradoxical pattern of GH response to OGTT.

CDKN2A (p16INK4A) affects the anti­tumor effect of CDK inhibitor in somatotroph adenomas.

The altered cell cycle is associated with aberrant growth factor signaling in somatotroph adenoma, which is the primary cause of acromegaly. The aim of the present study was to investigate the pathological role of the INK4 family and evaluate the effectiveness of CDK4 inhibitor, palbociclib, in somatotroph adenoma. RNA­Seq, RT­PCR, and immunohistochemistry were applied to measure the levels and correlations of the INK4 family with angiogenesis, CDKs, EMT, and therapeutic targets. MTS, flow cytometry, and ELISA were used to investigate the bio­activity in GH3 and GT1­1 cell lines after palbociclib treatment. Compared with lactotroph adenoma, gonadotroph adenoma, and corticotroph adenoma, somatotroph samples demonstrated higher expression of CDKN2A and SSTR2 but a lower expression of EGFR, CDK4, and CDH2 (P<0.05). CDKN2A positively correlates with SSTR2, and negatively with CDK4, EGFR, and CDH2. Patients with lower CDKN2A had larger tumor size (P=0.016) and more invasive potential (P=0.023). Palbociclib inhibited cell proliferation, induced G1 phase arrest, reduced GH/IGF­1 secretion of GH3 and GT1­1 cell lines (P<0.05), and had a more prominent role in GH3 cells (P<0.05). CDKN2A inhibited the bio­activity by modulating CDK4, and high CDKN2A predicted the insensitivity to CDK4 inhibitor, palbociclib, in somatotroph adenoma patients. In summary, the present study shows CDKN2A inhibited the bio­activity by modulating CDK4, and high CDKN2A predicts the insensitivity to CDK4 inhibitor, Palbociclib, in somatotroph adenoma patients.

Resistance to Dopamine Agonists in Pituitary Tumors: Molecular Mechanisms.

Pituitary neuroendocrine tumors (PitNET) are commonly benign tumors accounting for 10-25% of intracranial tumors. Prolactin-secreting adenomas represent the most predominant type of all PitNET and for this subtype of tumors, the medical therapy relies on the use of dopamine agonists (DAs). DAs yield an excellent therapeutic response in reducing tumor size and hormonal secretion targeting the dopamine receptor type 2 (D2DR) whose higher expression in prolactin-secreting adenomas compared to other PitNET is now well established. Moreover, although DAs therapy does not represent the first-line therapy for other PitNET, off-label use of DAs is considered in PitNET expressing D2DR. Nevertheless, DAs primary or secondary resistance, occurring in a subset of patients, may involve several molecular mechanisms, presently not fully elucidated. Dopamine receptors (DRs) expression is a prerequisite for a proper DA function in PitNET and several molecular events may negatively modify DR membrane expression, through the DRs down-regulation and intracellular trafficking, and DR signal transduction pathway. The current mini-review will summarise the presently known molecular events that underpin the unsuccessful therapy with DAs.

Pegvisomant and Pasireotide LAR as second line therapy in acromegaly: clinical effectiveness and predictors of response.

BACKGROUND: The treatment of acromegaly resistant to first-generation somatostatin receptor ligands (SRLs) is often difficult. Pegvisomant and Pasireotide LAR are mostly used in these subset of patients, as second line therapies. Choice of the type of second line therapies is difficult, since predictors of response are still unclear, impairing personalized therapy. We aimed to investigate predictors of response to Pegvisomant and Pasireotide LAR. METHODS: Seventy-four acromegaly patients entered this observational, cross-sectional and retrospective study if (i) resistant to high dose first-generation SRLs and (ii) treated with Pegvisomant and Pasireotide LAR for at least 12 consecutive months. Patients treated with radiotherapy in the previous 10 years were excluded. RESULTS: Fourty-one patients were treated with Pegvisomant and 33 with Pasireotide LAR. At the end of the study, acromegaly was controlled in 35 patients treated with Pegvisomant (85.4%) and in 23 treated with Pasireotide LAR (69.7%). In this cohort, a poor Pegvisomant response and a shorter progression free time were observed in cases with tumor extension to the third ventricle (P = 0.004, HR: 1.6, 95%CI: 1.2-4.6), with a Ki67-Li >4% (P = 0.004, HR: 3.49, 95%CI: 1.4-4.0) and with pre-treatment IGF-I >3.3×ULN (P=0.03, HR: 1.3, 95%CI: 1.1-6.0). A poor Pasireotide LAR response and a shorter progression free time were observed in cases with tumor extension to the third ventricle (P=0.025, HR: 1.6 95%CI: 1.4-3.4), pre-treatment IGF-I >2.3×ULN (P=0.049, HR: 2.4, 95%CI: 1.4-8.0), absent/low SST5 membranous expression (P=0.023 HR: 4.56 95%CI: 1.3-6.4) and in patients carried the d3-delated GHR isoform (P=0.005, HR: 11.37, 95%CI: 1.3-20.0). CONCLUSION: Molecular and clinical biomarkers can be useful in predicting the responsiveness to Pegvisomant and Pasireotide LAR.

Surgical and Pharmacological Outcomes in Acromegaly: Real-Life Data From the Mexican Acromegaly Registry.

CONTEXT: Acromegaly registries constitute a valuable source of therapeutic outcome information in real-life. OBJECTIVE: The objective of this work is to analyze surgical and pharmacological outcomes in the Mexican Acromegaly Registry (MAR). DESIGN AND METHODS: Data were extracted from the MAR informatic platform. Surgical remission was defined by a postoperative postglucose (GH) of less than 1 ng/mL and an insulin-like growth factor 1 (IGF-1) of less than 1.2 × upper limit of normal (ULN). Pharmacological remission was defined by a basal GH of less than 1 ng/mL and an IGF-1 of less than 1.2 × ULN. RESULTS: A total of 650 surgical outcomes were analyzed (94.6% transsphenoidal). Surgical remission was achieved in 40.15%, whereas 44.15% remained biochemically active. Persistently active disease after surgery was significantly associated with harboring an invasive macroadenoma, a basal GH of greater than 10 ng/mL, and/or an IGF-1 of greater than 2 × ULN at diagnosis on bivariate and multivariate analysis. The outcome of monotherapy with first-generation somatostatin analogs (SSAs) was evaluated in 267 patients (adjunctive in 65%), of whom 28.4% achieved remission. Persistently active disease was significantly associated with harboring an invasive macroadenoma as well as with pretreatment basal GH and IGF-1 levels of greater than 10 ng/mL and greater than 2 × ULN, respectively, on bivariate and multivariate analysis. Combined therapy with SSA and cabergoline was analyzed in 100 patients, of whom 19% achieved remission and 44% remained active; in this subset of patients, only a pretreatment IGF-1 of greater than 2 × ULN was significantly associated with persistent disease activity. CONCLUSION: Surgical and pharmacological outcomes in acromegaly are highly dependent on tumor size/invasiveness as well as on the degree of hypersomatotropinemia.

miR-34a is upregulated in AIP-mutated somatotropinomas and promotes octreotide resistance.

Pituitary adenomas (PAs) are intracranial tumors associated with significant morbidity due to hormonal dysregulation, mass effects and have a heavy treatment burden. Growth hormone (GH)-secreting PAs (somatotropinomas) cause acromegaly-gigantism. Genetic forms of somatotropinomas due to germline AIP mutations (AIPmut+) have an early onset and are aggressive and resistant to treatment with somatostatin analogs (SSAs), including octreotide. The molecular underpinnings of these clinical features remain unclear. We investigated the role of miRNA dysregulation in AIPmut+ vs AIPmut- PA samples by array analysis. miR-34a and miR-145 were highly expressed in AIPmut+ vs AIPmut- somatotropinomas. Ectopic expression of AIPmut (p.R271W) in Aip-/- mouse embryonic fibroblasts (MEFs) upregulated miR-34a and miR-145, establishing a causal link between AIPmut and miRNA expression. In PA cells (GH3), miR-34a overexpression promoted proliferation, clonogenicity, migration and suppressed apoptosis, whereas miR-145 moderately affected proliferation and apoptosis. Moreover, high miR-34a expression increased intracellular cAMP, a critical mitogenic factor in PAs. Crucially, high miR-34a expression significantly blunted octreotide-mediated GH inhibition and antiproliferative effects. miR-34a directly targets Gnai2 encoding Gαi2, a G protein subunit inhibiting cAMP production. Accordingly, Gαi2 levels were significantly lower in AIPmut+ vs AIPmut- PA. Taken together, somatotropinomas with AIP mutations overexpress miR-34a, which in turn downregulates Gαi2 expression, increases cAMP concentration and ultimately promotes cell growth. Upregulation of miR-34a also impairs the hormonal and antiproliferative response of PA cells to octreotide. Thus, miR-34a is a novel downstream target of mutant AIP that promotes a cellular phenotype mirroring the aggressive clinical features of AIPmut+ acromegaly.

T2-signal intensity, SSTR expression, and somatostatin analogs efficacy predict response to pasireotide in acromegaly.

OBJECTIVE: T2-signal intensity and somatostatin (SST) receptor expression are recognized predictors of therapy response in acromegaly. We investigated the relationship between these predictors and the hormonal and tumoral responses to long-acting pasireotide (PAS-LAR) therapy, which were also compared with responsiveness to first-generation somatostatin receptor ligands (SRLs). DESIGN: The PAPE study is a cohort study. METHODS: We included 45 acromegaly patients initially receiving SRLs, followed by combination therapy with pegvisomant, and finally PAS-LAR. We assessed tumor volume reduction (≥25% from baseline), IGF-1 levels (expressed as the upper limit of normal), and T2-weighted MRI signal and SST receptor expression of the adenoma. RESULTS: Patients with significant tumor shrinkage during PAS-LAR showed higher IGF-1 levels during PAS-LAR (mean (S.D.): 1.36 (0.53) vs 0.93 (0.43), P = 0.020), less IGF-1 reduction after first-generation SRLs (mean (S.D.): 0.55 (0.71) vs 1.25 (1.07), P = 0.028), and lower SST2 receptor expression (median (IQR): 2.0 (1.0-6.0) vs 12.0 (7.5-12.0), P = 0.040). Overall, T2-signal intensity ratio was increased compared with baseline (mean (S.D.): 1.39 (0.56) vs 1.25 (0.52), P = 0.017) and a higher T2-signal was associated with lower IGF-1 levels during PAS-LAR (ß: -0.29, 95% CI: -0.56 to -0.01, P = 0.045). A subset of PAS-LAR treated patients with increased T2-signal intensity achieved greater reduction of IGF-1 (mean (S.D.): 0.80 (0.60) vs 0.45 (0.39), P = 0.016). CONCLUSIONS: Patients unresponsive to SRLs with a lower SST2 receptor expression are more prone to achieve tumor shrinkage during PAS-LAR. Surprisingly, tumor shrinkage is not accompanied by a biochemical response, which is accompanied with a higher T2-signal intensity.

Efficacy and safety of lanreotide autogel compared with lanreotide 40 mg prolonged release in Chinese patients with active acromegaly: results from a phase 3, prospective, randomized, and open-label study (LANTERN).

BACKGROUND: Lanreotide autogel is a somatostatin analog (SSA) approved for the treatment of acromegaly in 73 countries worldwide; however, it is not yet approved in China. The aim of this study was to evaluate the efficacy and safety of lanreotide autogel compared with lanreotide 40 mg prolonged release (PR) in Chinese patients with active acromegaly. METHODS: LANTERN was a phase 3, randomized, open-label, non-inferiority study. Patients with active acromegaly who had undergone surgery ≥3 months prior, or were unlikely or unable to undergo surgery, were treated with lanreotide autogel 60/90/120 mg (monthly deep subcutaneous injection) or lanreotide 40 mg PR (intramuscular injection every 7, 10, or 14 days) for 32 weeks. Primary endpoint was mean change-from-baseline in age-adjusted insulin-like growth factor-1 (IGF-1) standard deviation scores (SDS) at the end-of-study. Secondary endpoints included: growth hormone (GH) levels ≤2.5 µg/L or ≤ 1.0 µg/L, ≥20% reduction in tumor volume (TV) and safety. RESULTS: In total, 128 patients were randomized and received study treatment. Lanreotide autogel was non-inferior to lanreotide 40 mg PR: treatment difference (95% CI) for IGF-1 SDS between groups was - 0.32 (- 0.74, 0.11; per protocol population) and - 0.27 (- 0.63, 0.09; intention-to-treat [ITT] population), respectively. Reductions in IGF-1 (- 6.453 vs - 7.003) and GH levels (- 9.548 µg/L vs - 13.182 µg/L), and the proportion of patients with ≥1 acromegaly symptom (- 20.3% vs - 32.5%) were observed from baseline to end-of-study in lanreotide autogel and lanreotide 40 mg PR groups, respectively. In the lanreotide autogel group, 45.5% (25/55) patients achieved ≥20% reduction in TV compared with 50.9% (25/53) in lanreotide 40 mg PR group (ITT). Safety profiles were similar in both treatment groups. CONCLUSIONS: Lanreotide autogel was non-inferior to lanreotide 40 mg PR in Chinese patients with active acromegaly after 32 weeks of treatment. TRIAL REGISTRATION: Retrospectively registered on ClinicalTrials.gov: NCT02493517 (9 July 2015); prospectively registered on chinadrugtrials.org.cn: CTR20140698 (24 October 2014).

BRD4 as a therapeutic target for nonfunctioning and growth hormone pituitary adenoma.

BACKGROUND: Nonfunctioning pituitary adenoma (NFPA) and growth hormone pituitary adenoma (GHPA) are major subtypes of pituitary adenomas (PAs). The primary treatment is surgical resection. However, radical excision remains challenging, and few effective medical therapies are available. It is urgent to find novel targets for the treatment. Bromodomain-containing protein 4 (BRD4) is an epigenetic regulator that leads to aberrant transcriptional activation of oncogenes. Herein, we investigated the pathological role of BRD4 and evaluated the effectiveness of BRD4 inhibitors in the treatment of NFPA and GHPA. METHODS: The expression of BRD4 was detected in NFPA, GHPA, and normal pituitary tissues. The efficacies of BRD4 inhibitors were evaluated in GH3 and MMQ cell lines, patient-derived tumor cells, and in vivo mouse xenograft models of PA. Standard western blots, real-time PCR, and flow cytometry experiments were performed to investigate the effect of BRD4 inhibitors on cell cycle progression, apoptosis, and the expression patterns of downstream genes. RESULTS: Immunohistochemistry studies demonstrated the overexpression of BRD4 in NFPA and GHPA. In vitro and in vivo studies showed that treatment with the BRD4 inhibitor ZBC-260 significantly inhibited the proliferation of PA cells. Further mechanistic studies revealed that ZBC-260 could downregulate the expression of c-Myc, B-cell lymphoma 2 (Bcl2), and related genes, which are vital factors in pituitary tumorigenesis. CONCLUSION: In this study, we determined the overexpression of BRD4 in NFPA and GHPA and assessed the effects of BRD4 inhibitors on PA cells in vitro and in vivo. Our findings suggest that BRD4 is a promising therapeutic target for NFPA and GHPA.

Therapeutic Effect of a Novel Chimeric Molecule Targeting Both Somatostatin and Dopamine Receptors on Growth Hormone-Secreting Pituitary Adenomas.

BACKGROUND: Acromegaly is a rare disease primarily caused by growth hormone (GH)-secreting pituitary adenomas, and its treatment is costly. Moreover, some patients are unresponsive to treatment. Hence, there are increasing efforts to develop new drugs with improved effectiveness for this disease. BIM23B065 is a novel chimeric molecule that acts on both somatostatin and dopamine receptors. This study aimed to investigate the effects of BIM23B065 compared with those of a somatostatin receptor analog and a dopamine agonist. METHODS: The effects of BIM23B065 on the proliferation, GH and insulin-like growth factor-1 (IGF-1) levels, and extracellular signal-regulated kinase (ERK) 1/2 and cyclic AMP response element binding (CREB) phosphorylation of GH3 cells were investigated with MTS assay, enzyme-linked immunosorbent assay, and Western blotting, respectively. The dosage and treatment duration of BIM23B065 were tested in animal models of GH-secreting pituitary adenoma. The effect of BIM23B065 (3 mg/kg/day) on changes in IGF-1 levels before and after treatment was further investigated. RESULTS: In vitro, BIM23B065 treatment decreased GH release in the culture media and downregulated ERK 1/2 and CREB phosphorylation to 22% and 26%, respectively. In vivo, IGF-1 expression decreased to 50 % after 4 weeks of treatment with BIM23B065 using an osmotic pump implant. Moreover, magnetic resonance imaging results showed that the tumor size decreased significantly following treatment with BIM23B065 for 4 weeks. CONCLUSION: The novel chimeric molecule was effective in decreasing IGF-1 and GH levels and may serve as an effective therapeutic agent for acromegaly.