Standard of Care Versus Octreotide in Angiodysplasia-Related Bleeding (the OCEAN Study): A Multicenter Randomized Controlled Trial.

BACKGROUND & AIMS: Gastrointestinal angiodysplasias are vascular anomalies that may result in transfusion-dependent anemia despite endoscopic therapy. An individual patient data meta-analysis of cohort studies suggests that octreotide decreases rebleeding rates, but component studies possessed a high risk of bias. We investigated the efficacy of octreotide in reducing the transfusion requirements of patients with angiodysplasia-related anemia in a clinical trial setting. METHODS: The study was designed as a multicenter, open-label, randomized controlled trial. Patients with angiodysplasia bleeding were required to have had at least 4 red blood cell (RBC) units or parental iron infusions, or both, in the year preceding randomization. Patients were allocated (1:1) to 40-mg octreotide long-acting release intramuscular every 28 days or standard of care, including endoscopic therapy. The treatment duration was 1 year. The primary outcome was the mean difference in the number of transfusion units (RBC + parental iron) between the octreotide and standard of care groups. Patients who received at least 1 octreotide injection or followed standard of care for at least 1 month were included in the intention-to-treat analyses. Analyses of covariance were used to adjust for baseline transfusion requirements and incomplete follow-up. RESULTS: We enrolled 62 patients (mean age, 72 years; 32 men) from 17 Dutch hospitals in the octreotide (n = 31) and standard of care (n = 31) groups. Patients required a mean number of 20.3 (standard deviation, 15.6) transfusion units and 2.4 (standard deviation, 2.0) endoscopic procedures in the year before enrollment. The total number of transfusions was lower with octreotide (11.0; 95% confidence interval [CI], 5.5-16.5) compared with standard of care (21.2; 95% CI, 15.7-26.7). Octreotide reduced the mean number of transfusion units by 10.2 (95% CI, 2.4-18.1; P = .012). Octreotide reduced the annual volume of endoscopic procedures by 0.9 (95% CI, 0.3-1.5). CONCLUSIONS: Octreotide effectively reduces transfusion requirements and the need for endoscopic therapy in patients with angiodysplasia-related anemia. CLINICALTRIALS: gov, NCT02384122.

AGA Clinical Practice Update on the Use of Vasoactive Drugs and Intravenous Albumin in Cirrhosis: Expert Review.

DESCRIPTION: Cirrhosis is a major cause of morbidity and mortality in the United States and worldwide. It consists of compensated, decompensated, and further decompensated stages; median survival is more than 15 years, 2 years, and 9 months for each stage, respectively. With each stage, there is progressive worsening of portal hypertension and the vasodilatory-hyperdynamic circulatory state, resulting in a progressive decrease in effective arterial blood volume and renal perfusion. Vasoconstrictors reduce portal pressure via splanchnic vasoconstriction and are used in the management of variceal hemorrhage. Intravenous (IV) albumin increases effective arterial blood volume and is used in the prevention of acute kidney injury (AKI) and death after large-volume paracentesis and in patients with spontaneous bacterial peritonitis (SBP). The combination of vasoconstrictors and albumin is used in the reversal of hepatorenal syndrome (HRS-AKI), the most lethal complication of cirrhosis. Because a potent vasoconstrictor, terlipressin, was recently approved by the US Food and Drug Administration, and because recent trials have explored use of IV albumin in other settings, it was considered that a best practice update would be relevant regarding the use of vasoactive drugs and IV albumin in the following 3 specific scenarios: variceal hemorrhage, ascites and SBP, and HRS. METHODS: This expert review was commissioned and approved by the American Gastroenterological Association (AGA) Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership. It underwent internal peer review through standard procedures of Gastroenterology. These Best Practice Advice statements were drawn from a review of the published literature and from expert opinion. Some of the statements are unchanged from published guidelines because of lack of new evidence in the literature. Because systematic reviews were not performed, these Best Practice Advice statements do not carry formal ratings regarding the quality and evidence or strength of the presented considerations. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Vasoactive drugs should be initiated as soon as the diagnosis of variceal hemorrhage is suspected or confirmed, preferably before diagnostic and/or therapeutic endoscopy. BEST PRACTICE ADVICE 2: After initial endoscopic hemostasis, vasoactive drugs should be continued for 2-5 days to prevent early rebleeding. BEST PRACTICE ADVICE 3: Octreotide is the vasoactive drug of choice in the management of variceal hemorrhage based on its safety profile. BEST PRACTICE ADVICE 4: IV albumin should be administered at the time of large-volume (>5 L) paracentesis. BEST PRACTICE ADVICE 5: IV albumin may be considered in patients with SBP. BEST PRACTICE ADVICE 6: Albumin should not be used in patients (hospitalized or not) with cirrhosis and uncomplicated ascites. BEST PRACTICE ADVICE 7: Vasoconstrictors should not be used in the management of uncomplicated ascites, after large-volume paracentesis or in patients with SBP. BEST PRACTICE ADVICE 8: IV albumin is the volume expander of choice in hospitalized patients with cirrhosis and ascites presenting with AKI. BEST PRACTICE ADVICE 9: Vasoactive drugs (eg, terlipressin, norepinephrine, and combination of octreotide and midodrine) should be used in the treatment of HRS-AKI, but not in other forms of AKI in cirrhosis. BEST PRACTICE ADVICE 10: Terlipressin is the vasoactive drug of choice in the treatment of HRS-AKI and use of concurrent albumin can be considered when accounting for patient's volume status. BEST PRACTICE ADVICE 11: Terlipressin treatment does not require intensive care unit monitoring and can be administered intravenously through a peripheral line. BEST PRACTICE ADVICE 12: Terlipressin use is contraindicated in patients with hypoxemia and in patients with ongoing coronary, peripheral, or mesenteric ischemia, and should be used with caution in patients with acute-on-chronic liver failure grade 3. The benefits may not outweigh the risks in patients with serum creatinine >5 mg/dL and in patients listed for transplantation with a Model for End-stage Liver Disease ≥35.

Hepatorenal Syndrome With Acute Kidney Injury: Diagnosis and Medical Management.

OBJECTIVES: To review the current definitions and diagnostic criteria for acute kidney injury (AKI) and type 1 hepatorenal syndrome (HRS) now termed HRS-AKI and discuss the challenges in deciding the most appropriate medication regimens to treat patients with HRS-AKI. DATA SOURCES: PubMed (inception to April 2023) with bibliographies of retrieved articles searched for additional articles; organizational websites for clinical practice guidelines (CPGs). STUDY SELECTION AND DATA EXTRACTION: Randomized controlled trials (RCTs) evaluating albumin and vasoconstrictors for HRS-AKI. DATA SYNTHESIS: A major change in the most recent revision of definitions and diagnostic criteria for HRS-AKI is the elimination of the set cutoff serum creatinine values for AKI. This change should be considered when comparing studies of HRS-AKI over time. Albumin has been administered to both vasoconstrictor treatment and placebo groups in all recent RCTs; however, there has never been a large RCT evaluating a no-albumin group. Most prospective trials comparing a midodrine/octreotide combination or norepinephrine to placebo or terlipressin have enrolled less than 100 patients limiting any conclusions regarding clinically important outcomes. Terlipressin with albumin has shown mixed results for complete HRS-AKI reversal with no reductions in crude mortality but adverse effect concerns involving ischemic and pulmonary events. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Type 1 hepatorenal syndrome with acute kidney injury is a potentially life-threatening syndrome with diagnostic and treatment challenges. Albumin plus a vasoconstrictor has become the routine HRS-AKI treatment even though there has not been a large RCT evaluating a no-albumin group. Terlipressin is the vasoconstrictor of choice for HRS-AKI in current CPGs, but it has adverse effect concerns and, until recently, was not available in the United States. CONCLUSIONS: In conjunction with changes in the definitions and diagnostic criteria for HRS-AKI, debate continues regarding the optimal therapy for HRS-AKI, particularly considering recent trials demonstrating ischemic and pulmonary adverse events with terlipressin used in combination with albumin.

Liver transplant for primary biliary tract neuroendocrine tumor in a nine-year-old girl.

BACKGROUND: Neuroendocrine tumors (NETs) are rare epithelial neoplasms that arise most commonly from the gastrointestinal tract. In pediatrics, the most common site of origin is in the appendix, with the liver being the most common site of metastasis. Neuroendocrine tumors arising from the biliary tract are extremely rare. METHODS: We describe a case of a nine-year-old girl who presented with obstructive cholestasis and was found to have multiple liver masses identified on biopsy as well-differentiated neuroendocrine tumor with an unknown primary tumor site. RESULT: The patient underwent extensive investigation to identify a primary tumor site, including endoscopy, endoscopic ultrasound, and capsule endoscopy. The patient ultimately underwent definitive management with liver transplant, and on explant was discovered to have multiple well-differentiated neuroendocrine tumors, WHO Grade 1, with extensive infiltration into the submucosa of bile duct, consistent with primary biliary tract neuroendocrine tumor. CONCLUSION: Identifying the site of the primary tumor in NETs found within the liver can be challenging. To determine if an extrahepatic primary tumor exists, workup should include endoscopy, EUS, and capsule endoscopy. Children with well-differentiated hepatic NETs, with no identifiable primary tumor, and an unresectable tumor, are considered favorable candidates for liver transplantation.

Structural insights into somatostatin receptor 5 bound with cyclic peptides.

Somatostatin receptor 5 (SSTR5) is highly expressed in ACTH-secreting pituitary adenomas and is an important drug target for the treatment of Cushing's disease. Two cyclic SST analog peptides (pasireotide and octreotide) both can activate SSTR5 and SSTR2. Pasireotide is preferential binding to SSTR5 than octreotide, while octreotide is biased to SSTR2 than SSTR5. The lack of selectivity of both pasireotide and octreotide causes side effects, such as hyperglycemia, gastrointestinal disturbance, and abnormal glucose homeostasis. However, little is known about the binding and selectivity mechanisms of pasireotide and octreotide with SSTR5, limiting the development of subtype-selective SST analog drugs specifically targeting SSTR5. Here, we report two cryo-electron microscopy (cryo-EM) structures of SSTR5-Gi complexes activated by pasireotide and octreoitde at resolutions of 3.09 Å and 3.24 Å, respectively. In combination with structural analysis and functional experiments, our results reveal the molecular mechanisms of ligand recognition and receptor activation. We also demonstrate that pasireotide preferentially binds to SSTR5 through the interactions between Tyr(Bzl)/DTrp of pasireotide and SSTR5. Moreover, we find that the Q2.63, N6.55, F7.35 and ECL2 of SSTR2 play a crucial role in octreotide biased binding of SSTR2. Our results will provide structural insights and offer new opportunities for the drug discovery of better selective pharmaceuticals targeting specific SSTR subtypes.

Standards of care for medical management of acromegaly in pituitary tumor centers of excellence (PTCOE).

PURPOSE: A series of consensus guidelines on medical treatment of acromegaly have been produced in the last two decades. However, little information is available on their application in clinical practice. Furthermore, international standards of acromegaly care have not been published. The aim of our study was to report current standards of care for medical therapy of acromegaly, using results collected through an audit performed to validate criteria for definition of Pituitary Tumor Centers of Excellence (PTCOE). METHODS: Details of medical treatment approaches to acromegaly were voluntarily provided by nine renowned international centers that participated in this audit. For the period 2018-2020, we assessed overall number of acromegaly patients under medical treatment, distribution of patients on different treatment modalities, overall biochemical control rate with medical therapy, and specific control rates for different medical treatment options. RESULTS: Median number of total patients and median number of new patients with acromegaly managed annually in the endocrinology units of the centers were 206 and 16.3, respectively. Median percentage of acromegaly patients on medical treatment was 48.9%. Among the patients on medical treatment, first-generation somatostatin receptor ligand (SRL) monotherapy was used with a median rate of 48.7%, followed by combination therapies with a median rate of 29.3%. Cabergoline monotherapy was used in 6.9% of patients. Pegvisomant monotherapy was used in 7 centers and pasireotide monotherapy in 5 centers, with median rates of 7.9% and 6.3%, respectively. CONCLUSIONS: Current standards of care in PTCOEs include use of first-generation SRLs as the first medical option in about 50% of patients, as recommended by consensus guidelines. However, some patients are kept on this treatment despite inadequate control suggesting that cost-effectiveness, availability, patient preference, side effects, and therapeutic inertia may play a possible role also in PTCOE. Moreover, at odds with consensus guidelines, other monotherapies for acromegaly appear to have a marginal role as compared to combination therapies as extrapolated from PTCOE practice data. Presence of uncontrolled patients in each treatment category suggest that further optimization of medical therapy, as well as use of other therapeutic tools such as radiosurgery may be needed.

Newer parameters of the octreotide test in patients with acromegaly.

PURPOSE: Predicting the therapeutic effects of first-generation somatostatin receptor ligands (fg-SRLs) is important when assessing or planning effective treatment strategies in patients with acromegaly. The oft-used maximum growth hormone (GH) suppression rate parameter of the octreotide test has a suboptimal predictive value. Therefore, this study explored newer parameters of the octreotide test for predicting the therapeutic effect of long-acting fg-SRLs. METHODS: In this single-center retrospective study, the octreotide test parameters and the therapeutic effects of fg-SRL at 3 months were investigated in 45 consecutive treatment-naïve patients with acromegaly between April 2008 and March 2023. Additionally, the relationship between the octreotide test parameters and the therapeutic effects of fg-SRLs was investigated. Tumor shrinkage was evaluated based on changes in the longitudinal diameter of the macroadenomas. The area GH suppression rate-time under the curve (AUC) and the time to nadir GH level were calculated and compared with the maximum GH suppression rate. RESULTS: The AUC estimated reductions in serum insulin-like growth factor I, and tumor shrinkage. The time to nadir GH level predicted tumor shrinkage more robustly than the maximum GH suppression rate in patients with macroadenoma. CONCLUSION: The AUC and time to nadir GH level may potentially be newer parameters of the octreotide test for estimating the therapeutic effect of fg-SRLs.

Changes in multi-modality management of acromegaly in a tertiary centre over 2 decades.

PURPOSE: Acromegaly is a rare disease associated with chronic multisystem complications. New therapeutic strategies have emerged in the last decades, combining pituitary transsphenoidal surgery (TSS), radiotherapy or radiosurgery (RXT) and medical treatments. METHODS: This retrospective monocentric study focused on presentation, management and outcome of acromegaly patients diagnosed between 2000 and 2020, still followed up in 2020, with a minimum follow-up of 1 year, and comparison of the first vs. second decade of the study. RESULTS: 275 patients were included, 50 diagnosed before 2010 and 225 after 2010. 95% of them had normal IGF-1 levels (with or without treatment) at the last follow-up. Transsphenoidal surgery was more successful after 2010 (75% vs. 54%; p < 0.01), while tumor characteristics remained the same over time. The time from first treatment to biochemical control was shorter after 2010 than before (8 vs. 16 months; p = 0.03). Since 2010, RT was used less frequently (10% vs. 32%; p < 0.01) but more rapidly after surgery (26 vs. 53 months; p = 0.03). In patients requiring anti-secretory drugs after TSS, the time from first therapy to biochemical control was shorter after 2010 (16 vs. 29 months; p < 0.01). Tumor size, tumor invasiveness, baseline IGF-1 levels and Trouillas classification were identified as predictors of remission. CONCLUSION: The vast majority of patients with acromegaly now have successful disease control with a multimodal approach. They reached biochemical control sooner in the most recent half of the study period. Future work should focus on those patients who are still uncontrolled and on the sequelae of the disease.

Long-acting somatostatin analogs and well differentiated neuroendocrine tumors: a 20-year-old story.

PURPOSE: The specific indications of somatostatin analogs (SSAs) in patients with neuroendocrine tumor (NET) emerged over the time. The objective of this review is to summarize and discuss the most relevant data concerning long-acting SSAs in NET. METHODS: A narrative review was performed including publications focusing on therapy with the long-acting octreotide, lanreotide, and pasireotide in patients with NET. RESULTS: Long-acting SSAs confirm to be a manageable and widely used tool in patients with NET. Both long-acting octreotide and lanreotide are safe as the short-acting formulations, while patient compliance and adherence is further improved. Together with some randomized phase-3 trials, many retrospective and prospective studies have been performed in the last 20 years revealing a variable but substantial impact on progression free survival, not only in gastroenteropancreatic but also in lung and unknown primary NETs. The most frequent tumor response to SSAs is stable disease, but an objective response can be observed, more frequently by using high-dose schedules and in MEN1-related pancreatic NETs. Low tumor burden, low tumor grade (G1 and low G2), good performance status and use as first-line therapy are the main predictive factors to SSAs in NET patients. Pasireotide has been evaluated in few studies. This compound remains a promising SSA and would deserve to be further evaluated as a potential additional indication in NET therapy. CONCLUSIONS: Long-acting SSAs are an effective and safe initial therapy of patients with well differentiated NET, allowing tumor growth as well as symptoms control for long-time in selected patients.

Anesthetic key points in a patient with a terminal ileum neuroendocrine tumor and a rare carcinoid left heart disease presented for non-cardiac surgery: case report.

BACKGROUND: Carcinoid tumors are rare neuroendocrine malignancies presenting in an increasing number in our center. The incidence of carcinoid tumors is approximatively between 2.5 and 5 cases per 100,000 people of whom about 50% develop carcinoid syndrome. Once the carcinoid syndrome has developed, a carcinoid cardiomyopathy can occur. Carcinoid heart disease (CaHD) remains a serious and rare complication associated with a significant increase in morbidity and mortality. Although carcinoid tumors have been known and studied for several years, there are still scarce data on the anesthetic management and the peri operative period. CASE PRESENTATION: We describe a case of a Caucasian 44-year-old woman with an unusual presentation of left CaHD with an ileal neuroendocrine tumor and liver metastases. Our preoperative somatostatin administration protocol, limit the cardiac damage. The maintenance of stable hemodynamics, the use of balanced anesthetic technique, all along with a good understanding of the pathology, played a major role in the successful management of anesthesia. This case report allows us to introduce our decision algorithm for the management of this type of pathology in our tertiary hospital, Cliniques Universitaires Saint-Luc. CONCLUSION: Despite the paucity of data, anesthetic management of patients with carcinoid tumor can be safely performed with effective hemodynamic monitoring and a good understanding of the pathophysiology. Knowledge and application of a clear institutional algorithm for octreotide administration and multidisciplinary consultation at a referral center are essential for the management of these patients.

Octreotide's role in the management of post-esophagectomy chylothorax.

The use of octreotide in managing intrathoracic chyle leak following esophagectomy has gained popularity in the adult population. While the benefits of octreotide have been confirmed in the pediatric population, there remains limited evidence to support its use in the adults post-esophagectomy. Thus, we performed a single-institution cohort study to characterize its efficacy. The study was performed using a prospective, single-center database, from which clinicopathologic characteristics were extracted of patients who had post-esophagectomy chyle leaks. Kaplan-Meier and multivariable Cox regression analyses were performed to investigate the effect of octreotide use on chest tube duration (CTD), hospital length of stay (LOS), and overall survival (OS). In our cohort, 74 patients met inclusion criteria, among whom 27 (36.5%) received octreotide. Kaplan-Meier revealed no significant effect of octreotide on CTD (P = 0.890), LOS (P = 0.740), or OS (P = 0.570). Multivariable Cox regression analyses further corroborated that octreotide had no effect on CTD (HR = 0.62, 95% confidence interval [CI]: 0.32-1.20, P = 0.155), LOS (HR = 0.64, CI: 0.34-1.21, P = 0.168), or OS (1.08, CI: 0.53-2.19, P = 0.833). Octreotide use in adult patients with chyle leak following esophagectomy lacks evidence of association with meaningful clinical outcomes. Level 1 evidence is needed prior to further consideration in this population.

The Current and Promising Oral Delivery Methods for Protein- and Peptide-Based Drugs.

Drugs based on peptides and proteins (PPs) have been widely used in medicine, beginning with insulin therapy in patients with diabetes mellitus over a century ago. Although the oral route of drug administration is the preferred one by the vast majority of patients and improves compliance, medications of this kind due to their specific chemical structure are typically delivered parenterally, which ensures optimal bioavailability. In order to overcome issues connected with oral absorption of PPs such as their instability depending on digestive enzymes and pH changes in the gastrointestinal (GI) system on the one hand, but also their limited permeability across physiological barriers (mucus and epithelium) on the other hand, scientists have been strenuously searching for novel delivery methods enabling peptide and protein drugs (PPDs) to be administered enterally. These include utilization of different nanoparticles, transport channels, substances enhancing permeation, chemical modifications, hydrogels, microneedles, microemulsion, proteolytic enzyme inhibitors, and cell-penetrating peptides, all of which are extensively discussed in this review. Furthermore, this article highlights oral PP therapeutics both previously used in therapy and currently available on the medical market.

Pediatric Idiopathic Chylopericardium: A Case Managed with Thoracoscopic Window Pericardiotomy.

Idiopathic chylopericardium (CP) in the pediatric population is a rare entity with very few reported cases and is characterized by the accumulation of chyle in the pericardial cavity. There are no guidelines for the management of this rare entity. The present study reports a case of idiopathic CP in an infant and our experience of managing it by pericardial window creation using VATS and a multidisciplinary approach providing the optimum care for the child.

Prescribing Characteristics of Octreotide Immediate-Release and Long-Acting Release in Patients with Neuroendocrine Tumors.

BACKGROUND: Treatment recommendations for patients with neuroendocrine tumors (NETs) include the use of octreotide long-acting release (LAR) for long-term therapy and immediate-release (IR) as rescue therapy to control the breakthrough symptoms of carcinoid syndrome (CS). High doses of LAR are commonly used in clinical practice. This study aimed to evaluate the real-world utilization of LAR and preceding IR use at the prescription and patient levels. METHODS: We used an administrative claims database (2009-2018) containing privately insured enrollees. We calculated the normalized LAR dose from pharmacy claims and the initial mean IR daily dose at the prescription level. At the patient level, we conducted a retrospective cohort study that included patients continuously enrolled with ≥1 pharmacy claim of LAR and evaluated the frequency and the clinical reason for dose escalation of LAR. The definition of the above-label maximum dose of LAR was ≥30 mg/4 weeks. RESULTS: Nineteen percent of LAR prescriptions had an above-label maximum dose. Only 7% of LAR prescriptions had preceding IR use. There were 386 patients with NETs or CS vs. 570 with an unknown diagnosis. Comparing patients with NETs or CS to those with an unknown diagnosis, 22.3% vs. 11.0 % experienced dose escalations and 29.0% vs. 26.6% had IR use before dose escalation, respectively. LAR dose escalation occurred in 50.9% vs. 39.2% for symptom control, 12.3% vs. 7.1% for tumor progression control, and 16.6% vs. 6.0% for both reasons in NETs/CS and unknown groups, respectively. CONCLUSION: Octreotide LAR dosing above the label-maximum dose is common and IR rescue dosing appears to be underutilized.

Characteristics and response cutoff of octreotide suppression test in thyrotrophin (TSH)-secreting pituitary adenomas.

CONTEXT: Somatostatin analogs are recommended for preoperative therapy in thyrotrophin secreting pituitary adenomas (TSHomas). Octreotide suppression test (OST) was designed to differentiate TSHomas with resistance to thyroid hormones, while its ability to test the sensitivity of SSA has not been fully studied. OBJECTIVE: To test the sensitivity of SSA in TSHomas with OST. PATIENTS: We collected 48 pathologically confirmed TSHoma patients with complete 72 h' data of OST into analysis. INTERVENTION: Octreotide suppression test. MAIN OUTCOME: Sensitivity timepoint and cutoff of OST. RESULTS: During the entire OST, the TSH descended maximally 89.07% (73.85%, 96.77%), while the FT3 and FT4 declined slowly [43.40% (37.80%, 54.44%) and 26.59% (19.01%, 33.13%), respectively]. The 24th hour was the timepoint wherein the stability occurs for TSH, and the 48th hour for FT3 and FT4 during OST. In the patients who received both short- and long-acting somatostatin analogs (SSA), the 24-h timepoint was the most predictive timepoint for the percentage of TSH decline (Spearman's rank correlation analysis, r = .571, p < .001), while the 72-h timepoint was optimal for predicting the magnitude of TSH decline (Spearman's rank correlation analysis, r = .438, p = .005). In the 24th timepoint, a positive correlation was also observed between TSH suppression rate and the percentage decrease and absolute value decrease of FT3 and FT4. Furthermore, in patients treated with long-acting SSA, the 72-h timepoint was optimal for predicting both the percentage (Spearman's rank correlation analysis, r = .587, p = .01) and magnitude (Spearman's rank correlation analysis, r = .474, p = .047) of TSH decline. The 24th hour was the optimal timepoint with 44.54% (50% of median value of TSH in 72-hOST) decrease of TSH being the observing cutoff. The adverse effect of OST was predominantly occurred in the gastrointestinal system and no severe event occurred during OST. Paradoxical response could occur in OST and it did not influence the effect of SSA as long as sensitivity was confirmed. A high level of hormonal control was achieved in the SSA-sensitive patients. CONCLUSION: OST can be used as an efficient tool to guide the adequate use of SSA.

Optimal first-line treatment strategies of systemic therapy for unresectable gastrointestinal neuroendocrine tumors based on the opinions of Japanese experts.

There are several options for systemic therapy of gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN), including somatostatin analogues (SSA), molecular-targeted agents, cytotoxic agents, and peptide receptor radionuclide therapy. However, the effectiveness of each agent varies according to the primary site. Although SSA and everolimus are key drugs used for systemic therapy of neuroendocrine tumors arising from the gastrointestinal tract (GI-NET), the optimal strategy for selecting among these modalities remains unexplored. Japanese experts on GI-NET discussed and determined optimal first-line treatment strategies based on the results of previously reported pivotal trials. The consensus was reached that tumor aggressiveness and prognosis can be predicted using hepatic tumor load and Ki-67 labeling index, which are thought to be clinically important factors when selecting systemic therapy for unresectable GI-NET. SSA therapy is considered appropriate for patients with a low hepatic tumor load and low Ki-67 value and everolimus for those with contraindications to SSA therapy. There was also agreement that the treatment strategy should be determined according to whether the origin is in the midgut, considering the biological differences. Based on this strategy, the experts have tentatively created treatment maps and applied them in representative cases of unresectable GI-NET. Japanese experts proposed tentative maps for optimal first-line treatment in patients with unresectable GI-NET. Further investigation is warranted to validate the usefulness of these maps.

The effect of long-acting somatostatin analogues on the uptake of [177Lu]Lu-HA-DOTATATE.

PURPOSE: According to IAEA/EANM/SNMMI guidelines, long-acting somatostatin analogues (LA-SSAs) should be discontinued 4-6 weeks prior to peptide receptor radionuclide therapy (PRRT) to prevent somatostatin receptor saturation. The aim of this study was to determine the effect of continued use of long-acting SSAs during PRRT on the uptake of [177Lu]Lu-HA-DOTATATE on SPECT/CT. METHODS: Consecutive patients with neuroendocrine tumours who were treated with PRRT receiving 7.4 GBq of [177Lu]Lu-HA-DOTATATE were included. Patients were divided into 3 groups: (1) control (LA-SSA stopped > 6 weeks prior to PRRT), or continued treatment with (2) long-acting octreotide < 6 weeks prior to PRRT, or (3) long-acting lanreotide < 6 weeks prior to PRRT. The uptake of [177Lu]Lu-HA-DOTATATE was quantified in healthy tissues (spleen, liver, kidneys, bone marrow) and tumour lesions on SPECT/CT performed 24 h after PRRT. A Mann-Whitney U test was used to determine differences in uptake between the long-acting octreotide and long-acting lanreotide groups compared to the control group. RESULTS: Forty-two patients with 135 cycles of PRRT were included: 28 with lanreotide, 50 with octreotide, and 57 cycles without LA-SSAs. Uptake of [177Lu]Lu-HA-DOTATATE was significantly decreased in liver parenchyma in patients with lanreotide (p < 0.001) and in the spleen in patients with either octreotide or lanreotide (both p < 0.001). No differences were observed for uptake in kidneys, bone marrow, and blood pool. Uptake of [177Lu]Lu-HA-DOTATATE in tumours was the same in patients with lanreotide compared to the control (p = 0.862) and in patients with octreotide compared to the control (p = 0.201), independent of tumour location. CONCLUSION: Long-acting octreotide and lanreotide do not interfere with the uptake of [177Lu]Lu-HA-DOTATATE in tumour lesions 24 h post-injection. Uptake in healthy liver parenchyma significantly decreases after lanreotide administration prior to PRRT, while uptake in healthy spleen tissue significantly decreases with both octreotide and lanreotide administration.

Comparison of [18F]-OC PET/CT and contrast-enhanced CT/MRI in the detection and evaluation of neuroendocrine neoplasms.

OBJECTIVES: Gallium-68 (68Ga)-labeled somatostatin analog (SSA) PET imaging has been widely used in clinical practice of neuroendocrine neoplasms (NENs). Compared with 68Ga, 18F has a great practical and economic advantage. Although a few studies have shown the characteristics of [18F] AlF-NOTA-octreotide ([18F]-OC) in healthy volunteers and small NEN patient groups, its clinical value needs further investigation. Herein, this retrospective study aimed to evaluate the diagnostic accuracy of [18F]-OC PET/CT in detecting NENs, as well as to compare it with contrast-enhanced CT/MRI. METHODS: We retrospectively reviewed the data of 93 patients who had undergone [18F]-OC PET/CT and CT or MRI scans. Of these patients, there were 45 patients with suspected NENs for diagnostic evaluation, and 48 patients with pathologically confirmed NENs for detecting metastasis or recurrence. [18F]-OC PET/CT images were evaluated visually and semi-quantitatively by measuring maximum standardized uptake value of tumor (SUVmax), tumor-to-background SUVmax ratio (TBR), and SUVmax of hypophysis (SUVhypophysis). A total of 276 suspected NEN lesions were found in these 93 patients. The results of histopathology or radiographic follow-up served as the reference standard for the final diagnosis. RESULTS: Forty-five patients with suspected NENs were confirmed by histopathological examination via resection or biopsy. [18F]-OC PET/CT showed high radiotracer uptake in the lesions of G1-G3 NENs. [18F]-OC PET/CT showed superior performance with 96.3% of sensitivity, 77.8% of specificity, and 88.9% of accuracy in diagnosing NENs compared to CT/MRI. When cutoffs of SUVmax, TBR, and SUVhypophysis were 8.3, 3.1, and 15.4, [18F]-OC PET/CT had the best equilibrium between sensitivity and specificity for differentiating NEN from non-NEN lesions. For a total of 276 suspected NEN lesions, the sensitivity, specificity, and accuracy of [18F]-OC PET/CT for diagnosis of NENs were 90.5%, 82.1%, and 88.8%, respectively, and were higher than those of CT and MRI. G1 and G2 NENs had higher TBR and lower CT enhancement intensity than G3. The SUVmax and TBR had a positive correlation with CT enhancement intensity in G2 rather than in G1 or G3. CONCLUSIONS: [18F]-OC PET/CT is a promising imaging modality for initial diagnosis and detecting metastasis or postoperative recurrence in NENs.

The role of quantitative tumor burden based on [68 Ga]Ga-DOTA-NOC PET/CT in well-differentiated neuroendocrine tumors: beyond prognosis.

PURPOSE: We aimed to elucidate the role of quantitative tumor burden based on PET/CT of somatostatin receptors in well-differentiated neuroendocrine tumors (NETs). METHODS: This study enrolled patients with [68 Ga]Ga-DOTA-NOC PET/CT-positive advanced NETs who did not receive medical treatment prior to PET/CT. Tumor burden was calculated using methods based on the background threshold and relative fixed threshold values (30%, 40%, and 50%). The prognostic value of the measured tumor burden in reference to overall survival (OS) and progression-free survival (PFS) on treatment with octreotide long-acting repeatable (LAR) was assessed using Cox regression analysis, Harrell's C-index, and survival analysis. A classification and regression tree (CART) was used to determine the optimal threshold for tumor burden. RESULTS: A total of 204 patients were included. Somatostatin receptor-expressing tumor volume (SRETV) and liver SRETV derived from a relative fixed threshold of 30% (SRETV30 and liver SRETV30) were statistically significantly associated with OS (C-index: 0.802 [95% confidence interval (CI), 0.658-0.946] and 0.806 [95% CI, 0.664-0.948], respectively). Extrahepatic tumor burden was not correlated with OS (hazard ratio: 0.617, 95% CI: 0.241-1.574, P = 0.312). Among 155 patients with non-functional NETs with a ki-67 index of ≤ 10%, those with a high SRETV30 (P = 0.016) or high liver SRETV30 (P = 0.014) showed statistically significantly worse PFS on treatment with octreotide LAR. Patients receiving a higher dose of octreotide LAR normalized by SRETV30 or liver SRETV30 (a normalized dose or a liver normalized dose) showed prolonged PFS on treatment with octreotide LAR and a prolonged OS. CONCLUSION: Quantitative tumor burden based on [68 Ga]Ga-DOTA-NOC PET/CT was correlated with OS and PFS in patients with non-functional NETs with a ki-67 index of ≤ 10% who received octreotide LAR. Calculating normalized and liver normalized doses may help in selecting the starting dose of octreotide LAR.

Better Peptides via Chemical Glycosylation: Somatostatin Analogues Having a Human Complex-Type N-Glycan with Improved Drug Properties.

Somatostatin (somatotropin release-inhibiting factor, SRIF) is a growth hormone inhibitory factor in the form of a 14- or 28-amino acid peptide. SRIF affects several physiological functions through its action on five distinct SRIF receptor subtypes (sst1-5). Native SRIF has only limited clinical applications due to its rapid degradation in plasma. To overcome this obstacle, we have developed glycosylated SRIF analogues that possess not only metabolic stability but also high affinity to all five receptor subtypes by attaching human complex-type oligosaccharides. Such glycosylated SRIF analogues with improved pharmacokinetic profiles could be potent and novel therapeutic drugs for SRIF-related diseases in which several SRIF receptor subtypes are closely involved, and also shed light on new indications. Our results show that chemical glycosylation can be a powerful tool for the development of peptide and protein analogues superior to the original molecules with enhanced drug properties.