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Objective: The phase 3 CHIASMA OPTIMAL study assessed efficacy and safety of oral octreotide capsules (OOC) in patients with acromegaly controlled on injectable somatostatin receptor ligands (SRLs). Sensitivity analyses were conducted for efficacy endpoints using two methods of imputation (i.e., the process of replacing clinical data with substitution values) to address missing data points due to some subjects reverting back to their prior injectable SRL treatment. Methods: Patients were ≥18 years of age and had evidence of active acromegaly with an average IGF-I ≤ 1.0 x ULN (utilizing the IDS iSYS assay calibrated to WHO recombinant reference standard 02/254). At baseline, patients were randomized to receive OOC or placebo for 36 weeks. The primary endpoint was proportion of patients maintaining biochemical response, defined as IGF-I ≤1.0 x ULN (2-value average at weeks 34 and 36) (Samson et al. ENDO 2020). Per study protocol, patient study discontinuations were considered non-responders regardless of clinical response at the time of discontinuation (non-response imputation). Additional exploratory analyses were performed utilizing the last observation carried forward (LOCF) analysis, as well as a completers analysis of response among the subgroup that completed the entire 36 weeks on study drug. The response rates reported for the primary end point are slightly adjusted for stratification differences as prespecified in the statistical analysis plan. Results: Twenty-eight patients received OOC and 12 failed to maintain biochemical response based on the primary endpoint. Seven of these 12 patients discontinued treatment early - 5 due to treatment failure and 2 due to AEs. The remaining 5 patients completed the 36-week protocol on study drug. Of these 5 patients, 4 had IGF-I values between >1.0 and ≤1.3 x ULN and 1 completed the study with an IGF-I of 1.7 x ULN with no clinical symptoms. 58.2% of patients in the OOC group met the primary endpoint of maintenance of biochemical response at the end of study using the non-response imputation. Using LOCF imputation, 64.3% (18/28) of patients met this endpoint. Of those completing the study (N=21), 76.2% maintained response. Conclusion: CHIASMA OPTIMAL primary endpoint was assessed using the non-response imputation for patients who discontinued treatment early, with a 58.2% response rate. However, when assessing the response rate based on LOCF imputation, or in study completers, similar to other phase 3 studies for acromegaly, the rate was imputed at 64.3% and 76.2%, respectively.

Introduction: Acromegaly (Acro) is a systemic disease characterized by high growth hormone (GH) and insulin like growth factor-I (IGF-I), insulin resistance, glucose intolerance (IGT) and higher diabetes mellitus (DM) risk in 15% - 38% of patients (pts). Moreover, different medical therapies of Acro are reported to have variable effects on glucose metabolism. An association between blood glucose (BG) and serum IGF-I levels in patients with DM and Acro has been suggested, while IGF-I levels and hemoglobin A1c (HbA1c) correlation is still controversial because of the multifactorial influence.Study aim: to investigate glucose metabolism in pts with Acro resistant to 1st gen somatostatin receptor ligands (SRLs) treated with Pegvisomant (Peg) or Pasireotide LAR (Pasi). Patients and Methods: Retrospective, international, multicenter study; consecutive pts enrolled according to following inclusion criteria for at least 6 consecutive months: (1) resistant to 1st gen SRLs, (2) treated with Pasi or Peg for active Acro. Patients with concomitant treatments with known action on glucose metabolism were excluded, with the exception of glucocorticoid replacement for central hypoadrenalism. Results: 72 pts with active Acro, mean age at study entry 37 ±15 yrs, 47 females (65.3%). 28 (38.9%) pts were treated with Pasi and 44 pts with Peg (61.1%). Peg was monotherapy in 18 pts (40.9%) and in combo with first generation SRLs for 26 pts (59.1%). The number of pts with IGT and DM2 was superimposable between the 2 groups (Pasi and Peg). In Pasi group, 19 pts had Acro control (67.9%); glucose metabolism worsened in 16 pts (57.1%). Worsening of glucose metabolism occurred most frequently in pts with persistently active Acro (62.5%) and in pts with higher BG and HbA1c values at study start. Similarly, HbA1c was higher in pts with active Acro, although HbA1c worsened during Pasi treatment both in euglycemic and IGT at study entry, regardless of Acro control. In Peg group, 31 pts reached Acro control (73%); glucose metabolism worsened in 12 (27.3%) but improved in 5 pts (11.4%). All pts who experienced glucose metabolism improvement had controlled Acro, regardless of the use of a combo with first generation SRL. Among the 13 pts with active Acro after Peg, BG worsened in 5 cases (38.4%). Moreover, we found that pts with worsening BG control had higher HbA1c (p=0.03) and required higher Peg doses (mean ±SD 25 ±10 mg/day; p=0.04). Patients with higher HbA1c had higher IGF-I, both at study entry and at study end and were treated with higher Peg dose (mean 25 mg/day). Conclusion: Impaired glucose metabolism was more frequent after Pasireotide treatment and in patients of both Pasireotide and Pegvisomant groups with altered pre-treatment glucose and persistently active disease. Therefore, in such acromegaly patients close monitoring of glucose status is recommended during treatment.

Introduction: Prolactinomas are the most frequent pituitary-secreting tumors. Medical therapy with cabergoline (CAB), a dopamine agonist (DA), is the first line treatment, but 10% of prolactinomas are resistant to CAB. Recently, in vitro studies have shown anti-tumoral activity of metformin and other biguanids in human prolactinomas1, which prompted us to investigate that possibility in vivo. Aim: To evaluate the effect of metformin (MET) on Prolactin (PRL) secretion in patients with CAB resistant prolactinomas. Design and Setting: Prospective interventional study in a single referral center. Subjects: Ten patients (7 M; mean age: 44 ± 12y) with CAB resistant (PRL: 148 ± 125ng/ml; range: 38 - 386) prolactinomas (all macroadenomas) and metabolic syndrome on maximally tolerated CAB doses (4.3 ± 1.2 mg/week; range: 2.0-7.0) for ≥ 6 months (45 ± 39mo; range: 6-120). Intervention: Oral extended release metformin (p.o.) was prescribed according to patient’s tolerance (mean dose: 1.3 ± 0.4 g; range: 1.0-2.0). Main Outcome Measurements: Serum PRL (Elecsys, Roche, Indianapolis, USA), body weight (BW), fasting glycemia (FG) and HbA1C were evaluated before and at two time points during metformin treatment (30-60 and 120-180 days). Results: BW, FG, and/or HbA1C reductions were observed in 9/10 patients and mean FG decreased significantly (P=0.04). No significant changes were observed in serum PRL levels during metformin treatment [134 ± 124 ng/ml vs 138 ± 132 ng/ml vs 144 ± 129 ng/ml, before, at 30-60 days and at 120-180 days, respectively (P=0.499, mixed-effects analysis with the Geisser-Greenhouse correction)]. Individually, two patients exhibited a ≥ 50% decrease in PRL levels at a single timepoint (one at 30-60 days, with a further increase at 120-180 days and the other at 120-180 days). Conclusion: Metformin, at usual doses, did not inhibit prolactin secretion in patients with cabergoline-resistant prolactinomas. The discrepancy between our results and in vitro studies is not clear, but may be related to the much higher concentrations of metformin used in vitro1 as compared to the serum concentrations observed in patients during metformin treatment2. References: 1Gao J et al. Metformin inhibits growth and prolactin secretion of pituitary prolactinoma cells and xenografts. J Cell Mol Med. 2018 22:6368-79; 2 Frid A et al. Novel assay of metformin levels in patients with type 2 diabetes and varying levels of renal function: clinical recommendations. Diabetes Care 2010 33:1291-3.

Background: Injectable somatostatin receptor ligands (SRLs) are the most widely used therapy to control acromegaly. Oral octreotide capsules have been formulated as a potential therapy for this disorder and the efficacy and safety was evaluated in the CHIASMA OPTIMAL prospective phase 3 study in patients with acromegaly who were controlled on injectable SRL treatment of varying doses (Samson et al. ENDO 2020). Methods: Patients with confirmed acromegaly, who had been receiving a stable dose of injectable SRL (≥3 months) up until study entry, were randomized to receive octreotide capsules (40 mg/day) or placebo for 36 weeks. Patients were dose titrated to 60 or 80 mg of oral octreotide or equivalent placebo through week 24 at the investigator’s discretion based on increase of IGF-I levels or worsening of acromegaly signs and symptoms. The primary efficacy endpoint was the proportion of patients who maintained their biochemical response at the end of 36 weeks, defined as average IGF-I ≤1 x ULN between Weeks 34 and 36. An analysis evaluated maintenance of response based on prior dose of injectable SRL. Prior doses of injectable SRL were categorized based on the following classifications: octreotide 10 mg every 4 weeks or lanreotide 60 mg every 4 weeks or 120 mg every 8 weeks were stratified as low; octreotide 20 mg every 4 weeks or lanreotide 90 mg every 4 weeks or 120 mg every 6 weeks were stratified as medium; octreotide 30 mg or 40 mg or lanreotide 120 mg every 4 weeks were stratified as high. Randomization was stratified based on low dose vs med/high dose and efficacy results compared for these strata. The response rates reported for the primary end point are slightly adjusted for stratification differences as prespecified in the statistical analysis plan. Results: Six patients (21.4%) in the octreotide capsule group had received prior treatment with low doses of injectable SRLs while 22 (78.6%) had received prior treatment with medium-high doses of injectable SRLs. Maintenance of response was observed in 16 patients receiving oral octreotide. This included 66.7% of patients (n=4) previously receiving low doses of injected SRLs and 54.5% of patients (n=12) on medium-high injected doses. The treatment effect was consistent irrespective of prior dose of injectable SRL (odds ratio: 5.4 in low dose and 5.9 in medium-high dose). Conclusion: The CHIASMA OPTIMAL study recruited a population receiving predominantly medium-high doses of injectable SRLs and demonstrated maintenance of response in 58% of patients. Oral octreotide treatment effect was consistent irrespective of prior dose of injectable SRL.

Background: A new lanreotide autogel/depot (LAN) syringe was developed based on feedback from a human factors study to improve user experience. Methods: PRESTO was a multinational, simulated-use study in nurses with ≥2 years’ experience injecting LAN or octreotide long-acting release (OCT LAR) in patients with acromegaly and/or neuroendocrine tumors, which aimed to assess injector preference between the LAN new syringe and the current OCT LAR syringe. Participating nurses were invited to test both the LAN new syringe (120 mg) and the current OCT LAR syringe (20 mg or 30 mg), using injection pads. The sponsor was not involved in these sessions. In an anonymous web-based questionnaire, nurses reported overall preference (‘strong’ or ‘slight’; primary endpoint), and rated and ranked the importance of nine attributes for each syringe (1 [not at all] to 5 [very much]). Results: In total, 90 nurses attended injection sessions and completed valid questionnaires. Overall, 97.8% of nurses expressed a preference (85.6% ‘strong’, 12.2% ‘slight’) for LAN new syringe (p Conclusions: The PRESTO study showed that nurses preferred the user experience of the LAN new syringe over the current OCT LAR syringe across all attributes tested.

Distinguishing non-specific signs and symptoms of acromegaly from treatment emergent adverse events (TEAEs) in patients treated with somatostatin receptor ligands has proven difficult given limited data from placebo-controlled studies. The phase 3 Octreotide capsules versus Placebo Treatment In MultinationAL centers (OPTIMAL) study provides a novel data set to evaluate the incidence of adverse events from patients randomized to octreotide capsules or placebo. A multinational, randomized, placebo-controlled study was conducted in 56 adult patients with active acromegaly. Eligible patients were ≥18 years of age, had active disease (IGF-I ≥1.3 x ULN after last pituitary surgery), and an average IGF-I ≤1.0 x ULN in response to a stable dose of somatostatin receptor ligand injection. Patients were randomized to octreotide capsule or placebo (28 per group) for 36 weeks, followed by an optional open-label extension for up to 1 year. Safety and tolerability were evaluated based on incidence of AEs, including incidence of new or worsening adverse events of special interest (AESIs). In this study, the safety profile of octreotide capsules was consistent with the known safety profile of injectable octreotide (Melmed et al 2015). No new or unexpected safety signals were detected. Nearly all patients (55/56) experienced a TEAE (28 patients [100.0%] in the octreotide capsule group and 27 patients [96.4%] in the placebo group). Thirty-three patients (58.9%) experienced a TEAE considered to be related to study drug by the blinded PI (64.3% of the octreotide capsule group [18 patients, 40 events] and 53.8% of the placebo group [15 patients, 41 events]). TEAEs with an incidence ≥5% that were more common in the octreotide capsule group vs placebo group included GI disorders, increased blood glucose, sinusitis, osteoarthritis, and cholelithiasis. TEAEs with an incidence ≥5% that were more common in the placebo group vs octreotide capsule group included arthralgia, headache, fatigue, hyperhidrosis, and peripheral swelling. GI disorders were the most common TEAE, reported in 64% of all patients (36/56) and at similar rates between octreotide capsule (68%) and placebo groups (61%). AESIs (defined as new or worsening signs of acromegaly) were observed in 15 patients (53.6%, 34 events total) in the octreotide capsule group and more frequently in 26 patients (92.9%, 82 events total) in the placebo group. In this study, the safety profile of octreotide capsules was consistent with the known safety profile of injectable octreotide. Most patients receiving octreotide capsules or placebo demonstrated TEAEs, although the profile of most common TEAEs varied between groups. TEAEs observed in the placebo group may be indicative of underlying disease activity. Further analysis may elucidate the difference between treatment related AEs and signs/symptoms of active disease in acromegaly.