Advisory Board Research Articles

6418 Treatment of Subclinical Hyperthyroidism and Incident Atrial Fibrillation

Abstract Disclosure: M. Jay: None. P. Huan: None. N. Cliffe: None. J. Rakoff: None. E. Morris: None. P. Kavsak: Advisory Board Member; Self; Roche Diagnostics, QuidelOrtho, Siemens. Consulting Fee; Self; QuidelOrtho, Roche Diagnostics. Grant Recipient; Self; QuidelOrtho. Speaker; Self; Abbott Laboratories. Other; Self; Siemens(Other Research Support (includes receipt of drugs, supplies, equipment or other in-kind support), Speaker/Honoraria)). M. Luthra: Advisory Board Member; Self; Bayer, Inc., Novonordisk. Consulting Fee; Self; Bayer, Inc., Novonordisk. Speaker; Self; Lilly/BI alliance, Novonordisk, Sanofi. Z. Punthakee: None. Background: Treating overt hyperthyroidism prevents atrial fibrillation (AF). Though subclinical hyperthyroidism (SH) has been associated with AF risk, it is unknown whether treating SH prevents AF. Objective: We aimed to identify the association between treating SH and incident AF in outpatients. Methods: In a retrospective chart review, 2169 patients ≥ 18 years, diagnosed with SH between 2000-2021 were identified using the regional biochemistry database. After excluding those with prior AF, hypothyroidism, thyroid cancer, pituitary disease, and pregnancy, 360 patients categorized as treated (n=131) or untreated (n=229) were analyzed. The primary outcome was incident AF. Incidence rates were compared between the two groups over the time since SH treatment start for the treated group, and time since diagnosis of SH for the untreated group. Pharmacoepidemiologic Cox analysis adjusted for age and hypertension, with treatment as a time dependent covariate was used to account for untreated time in the treated group. Secondary outcomes were AF prevalence, P wave duration on ECG, as well as ventricular and ascending aorta diameters on echocardiogram. We included sensitivity and subgroup analyses. Results: Mean age of patients with SH was 55.19 years, 78% were female, 43% had toxic nodules and 14% had Grave’s disease. Amongst the 19 patients who developed AF, 58% had toxic nodules and no patient had Grave’s disease. In the treated and untreated groups, AF occurred in 3.1% and 6.6% (p=0.15) and AF incidence was 0.8 and 1.4 %/year (p=0.31), respectively. The hazard ratio (HR) was 0.60 (95% CI 0.19-1.92; p=0.39). In the subgroup of patients with free T4 (FT4) ≥ 15 pmol/L, AF incidence was 0.5 and 3.0 %/yr in the treated and untreated groups, respectively (p=0.01), while adjusted HR was 0.185 (95% CI 0.022-1.59, p=0.12). In those with TSH ≤ 0.1 mU/L, treatment was not associated with AF incidence. As some cases of AF were documented nearly simultaneously with treatment of SH, a sensitivity analysis was performed reassigning 2 patients diagnosed with AF <30 days after starting SH treatment to the untreated group. Here, in the treated and untreated groups, AF occurred in 1.6% and 7.4% (p=0.02), and AF incidence was 0.4 and 1.8 %/year (p=0.02), respectively. The HR was 0.25 (0.06-1.13; p=0.07). In the treated versus untreated groups, the mean p wave duration, ventricular diameter, and ascending aorta diameter were 73.47 vs 73.42 ms (p=0.99), 4.29 vs 4.34 cm (p=0.86), and 3.33 vs 3.23 cm (p=0.58), respectively. Conclusions: We report the first study assessing the effect of treating SH in preventing incident AF. There was an overall trend towards lower AF following treatment of SH. Lack of statistical significance may be related to small sample size, supporting the need for larger scale studies. These data suggest the etiology of SH (toxic nodules) and FT4 levels could be factored into treatment decisions. Presentation: 6/2/2024

7255 Tirzepatide Helps Achieve Glycemic Control and Lower Triglycerides in Seven Patients with Lipodystrophy

Abstract Disclosure: R. Meral: None. E.D. Frontera: None. M. Celik Guler: None. M.C. Foss de Freitas: None. N. Nachawi: None. D.T. Broome: Consulting Fee; Self; Tayco, Inc.. Research Investigator; Self; Novo Nordisk, Fractyl Laboratories, Rhythm Pharmaceuticals. S.I. Taylor: None. E.A. Oral: Advisory Board Member; Self; Amryt, Regeneron Pharmaceuticals. Consulting Fee; Self; Regeneron Pharmaceuticals, Amryt, Third Rock Ventures. Grant Recipient; Self; Regeneron Pharmaceuticals, Amryt. Research Investigator; Self; Novo Nordisk, Fractyl, Ionis Pharmaceuticals Inc., GI Dynamics, Rhythm Pharmaceuticals. Other; Self; Amryt. Lipodystrophy encompasses a group of rare disorders associated with severe metabolic disease. These disorders are defined by abnormal distribution of fat, with near-total (generalized lipodystrophy, GL) or partial (partial lipodystrophy, PL; i.e. familial partial lipodystrophy, FPLD) absence of adipocyte mass leading to a decreased ability to store triglycerides safely. Excess triglycerides are more likely to be stored in ectopic tissues such as hepatocytes, which leads to the metabolic manifestations of the disease state. Patients with GL have near absent levels of leptin hormone and leptin replacement therapy leads to dramatic improvement, which has mainly been attributed to a reduction in caloric intake. Patients with PL are not as leptin deficient and their response to leptin replacement therapy has been variable. We hypothesized that the clinical use of tirzepatide in patients with lipodystrophy may lead to favorable outcomes through the reduction of caloric intake. We closely observed 7 patients who were prescribed tirzepatide for their diabetes with information presented respectively [Age: 44; 54; 34; 53; 44; 46; 38 years | Sex: F; F; F; F; F; M; F | Subtype: FPLD type 1; FPLD type 2; FPLD type 1; Acquired GL; FPLD type 2; FPLD type 1; FPLD type 3]. At baseline, all patients had poor control of their disease despite aggressive medical therapy (except patient #5). Follow-up durations varied due to the observational nature of the study [follow-up duration (months): 6; 12; 7; 3; 8; 9; 5]. Reductions in A1c, triglycerides, and body mass index (BMI) were observed [A1c (%): 13.4->7.1; 7.1->6.6; 7.6->5.2; 8.7->6.9; 5.4->5.1; 8.9->7.8; 9.7->7.1 | triglycerides (mg/dL): 539->339; 164->109; 367->NA; 151->113; 388->101; 459->319; 4081->259 | BMI (Kg/m2): 25.0->24.5; 30.6->28.3; 37.7->33.9; 22.8->20.9; 27.6->23.4; 40.1->37.9; 24.0->24.9]. Those who were on insulin had decreased daily requirements [total daily insulin requirement (units): 160->25; 82->18; not on insulin; 85->0; not on insulin; 280->200; 124->111]. All patients reported a reduction in their daily food intake. Treatment related complications were limited to known gastrointestinal issues which the patients rated as tolerable. Based on our results, a randomized controlled trial to test the efficacy of tirzepatide in patients with lipodystrophy may be warranted. Presentation: 6/3/2024

5124 Increased Copeptin May Reflect Vasopressin-Related Metabolic Changes After Bariatric Surgery

Abstract Disclosure: F. Galbiati: None. A. Aulinas Maso: None. I. Becetti: None. M. Lauze: None. V. Singhal: None. E.A. Lawson: Research Investigator; Self; received research funding and study drug from Tonix Pharmaceuticals. M. Bredella: None. M. Bredella: None. M. Misra: Advisory Board Member; Self; key opinion leader for Lumos Pharma. Consulting Fee; Self; Up To Date, Receives royalties. Objective: Vasopressin (AVP) is a neurohormone that decreases fat mass, promotes muscle regeneration, improves glucose homeostasis, and protects against hypoglycemia in animals and humans. Copeptin, a stable cleavage product of AVP, is positively associated with body mass index (BMI), insulin resistance, and metabolic syndrome in adults, suggesting an adaptive increase in AVP to counteract metabolic disruption. Similarly, copeptin was positively correlated with BMI in children. Metabolic and bariatric surgery (MBS) is highly effective at reducing metabolic complications of obesity, and underlying mechanisms may provide insights into novel therapeutics for obesity management. No study has investigated copeptin pre- and post-MBS in humans. We hypothesized that after MBS, (1) copeptin would increase and (2) increased copeptin would be associated with improved metabolic parameters. Methods: Longitudinal study in 64 adolescents and young adults (78% females; age [mean±SD] 18.7±2.8 years) with obesity (BMI 45.6±6.8 kg/m2). 34 underwent MBS (sleeve gastrectomy or Roux-en-Y gastric bypass) and 30 underwent non-surgical (NS) lifestyle management. We measured fasting circulating copeptin, %fat, and lean mass by dual-energy X-ray absorptiometry, hemoglobin A1c (HbA1c), and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) at baseline and 12 months. Results: Groups were similar for age, sex, race, and pubertal stage. Baseline BMI and %fat were higher in MBS (p≤.012). Baseline copeptin, %lean mass, HbA1c, and HOMA-IR did not differ across groups (p≥.103). MBS vs NS 12-month changes were [median(IQR)]: BMI -29.0 (-33.7, -16.5)% and 0.54 (-3.10, +4.37)%; %fat -8.03 (-13.33, -4.25) and -0.68 (-2.92, 0.64); %lean mass 7.73 (3.45, 12.38) and 0.83 (-.58, 2.73); HbA1c -0.40 (-0.52, -0.20) and -0.10 (-0.20, -0.02); HOMA-IR (mean±SD) -2.47±2.17 and 0.76±2.42 (ps≤.001). Baseline copeptin was correlated negatively with %fat (rho=-.25; p=.045), and positively with %lean mass (trend-level rho=.25, p=0.051). Copeptin increased in the MBS group and decreased in the NS group (time-x;-treatment effect: p=.017). Overall, copeptin change was correlated negatively with %fat change (rho=-.29; p=.025) and positively with %lean mass change (trend-level rho=0.24, p=.070). Copeptin change was positively correlated with changes in %lean mass (rho=.37, p=.045), HbA1c (rho=.46; p=.010), and HOMA-IR (rho=.53; p=.004), only after MBS. Conclusion: Overall, increase in copeptin over 12 months was associated with improved body composition, suggesting that increased AVP following MBS may contribute to its associated metabolic improvements. However, within the MBS group, improved glucose homeostasis was associated with reductions in copeptin, suggesting a possible protective mechanism against post-bariatric hypoglycemia. Presentation: 6/2/2024

9318 Growth Response To Oral Growth Hormone Secretagogue LUM-201 In Children With Moderate GH Deficiency (GHD) Is Dependent On The Pattern Of Pulsatile GH Secretion Induced By LUM-201

Abstract Disclosure: A. Roslan: None. R. Roman: None. A. Avila: None. D. Said: None. I. Baier: None. E. Brincks: Employee; Self; Lumos Pharma, Inc.. Stock Owner; Self; Lumos Pharma, Inc. A. Bruchey: Employee; Self; Lumos Pharma, Inc.. Stock Owner; Self; Lumos Pharma, Inc. J. McKew: Employee; Self; Lumos Pharma, Inc.. Stock Owner; Self; Lumos Pharma, Inc. P. Pitukcheewanont: Employee; Self; Lumos Pharma, Inc.. Stock Owner; Self; Lumos Pharma, Inc.. M. Johnson: None. T. Garner: Consulting Fee; Self; Lumos Pharma, Inc.. Grant Recipient; Self; Novo Nordisk. M.O. Thorner: Consulting Fee; Self; Lumos Pharma, Inc.. Stock Owner; Self; Lumos Pharma, Inc. P.E. Clayton: Advisory Board Member; Self; Lumos Pharma, Inc.. Consulting Fee; Self; Lumos Pharma, Inc.. Grant Recipient; Self; Novo Nordisk. A. Stevens: Consulting Fee; Self; Lumos Pharma, Inc. F. Cassorla: Consulting Fee; Self; Lumos Pharma, Inc.. Background: Oral GH secretagogue, LUM-201, increases growth rates in children with moderate GHD in Phase 2 trials (OraGrowtH210 and 212) [ENDO 2023, OR21-06]. GH pulse profiles at baseline (D1) and 6 months (6M) were assessed in OraGrowtH212. This study aims to understand relationships between pulse profiles and growth response to LUM-201. Methods: The OraGrowtH212 trial is being conducted at a single site (Chile). 22 prepubertal children (M 14: F 8) with moderate GHD (peak GH level on two stimulation tests >3 and <10ng/ml), who had basal IGF-I >30ng/ml and an acute GH response to 0.8mg/kg LUM-201 of ≥5ng/ml, were randomised to receive LUM-201 1.6 or 3.2 mg/kg/day. 10min samples over 12hrs (08.00-20.00) were collected at D1 and M6 for measurement of GH concentration (ng/ml), with GH secretion rates (ng/ml/min) derived by deconvolution analysis. A univariate Spearman’s rank correlation matrix was used to screen for relationships (significant at p<0.05) between D1 characteristics, D1 height velocity, 6M annualised height velocity (AHV) and interpulse, pulsatile and total GH secretion at D1 and M6.The pattern of pulsatile GH secretion in the 12hr profile was characterised using Functional Principal Component Analysis (FPCA) - used to explore the dominant modes of variation in functional data, in this case the GH time series. Subjects were grouped into tertiles based on 6M AHV (High [mean 8.9cm/yr], Medium [7.7], and Low [6.7]), and the 12hr profiles were divided into three 4hr intervals. The interquartile range (IQR) for mean GH secretion (representing variation in amount) and principal components [PCs] (variation in pattern) for all subjects in each AHV tertile at D1 and M6 were generated. Results: All GH secretion parameters increased significantly from D1 to M6 (p<0.01). Age was negatively associated with 6m AHV (rs= -0.46), and D1 pulsatile GH secretion was positively associated with D1 AHV (rs = +0.51). However, GH secretion at D1 and M6 was not correlated with 6m AHV. In the FPCA, the difference in IQR for mean GH secretion from D1 to 6M was highest over 0-4hrs for subjects in the high and medium AHV tertiles (5- and 3.3-fold greater respectively compared to the other time intervals), while subjects with low AHV had the highest difference over 8-12hrs (42-fold greater). Using the first PC (which accounts for ∼50% of total variation), the change in IQR was highest over 0-4 and 4-8hrs in the high AHV tertile (3-fold greater compared to other time intervals), over 0-4hrs in the medium tertile (46-fold greater) and over 8-12hrs in the low tertile (3.4-fold greater). Conclusions: Oral LUM-201 stimulates significant increases in GH secretion over 6 months in children with moderate GH deficiency. Complex relationships exist between growth response and both the amount and pattern of GH secretion, with the highest growth responses to LUM-201 associated with the greatest pulsatile activity early in the profile. Presentation: 6/3/2024

8026 Growth Hormone Receptor (GHR) is Independently Associated with Body Composition and Glycemic Measures in Youth with Type 2 Diabetes (T2D)

Abstract Disclosure: C. Lu: None. D. Wolfs: None. L. El ghormli: None. L.M. Laffel: None. M. Patti: Advisory Board Member; Self; Fractyl Health. Consulting Fee; Self; AstraZeneca, Hamni, MBX Biosciences. Grant Recipient; Self; Dexcom. E. Isganaitis: None. Background: T2D is more severe in youth than in adults, with growth and puberty as potential drivers. Growth hormone (GH) action, which peaks during puberty, also regulates carbohydrate metabolism. We previously showed that higher plasma levels of GHR are associated with hyperglycemia, insulin resistance, and decreased insulin secretion in youth with T2D. Plasma GHR is higher in obesity, and reductions in GHR after bariatric surgery may mediate improvements in glycemia. The association of GHR with body composition in youth with T2D has not been previously studied. Hypothesis: We hypothesize that the association of GHR with glycemic outcomes in youth with T2D is mediated by differences in body composition, and that associations between GHR and body composition differ by sex. Methods: Utilizing plasma samples from Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study (N=398), we examined association of plasma GHR (ELISA; ng/mL) with a) body composition measures including zBMI, absolute lean mass (kg), percent body fat (dual-energy x-ray absorptiometry), and b) glycemic outcomes including hemoglobin A1c (HbA1c), fasting glucose (mg/dL), 1/fasting C-peptide (mL/ng), C-peptide index (ng/mL per mg/dL), and C-peptide oral disposition index (CODI; mL/uU x ng/mL per mg/dL), stratified by sex. Linear regressions were adjusted for age, race/ethnicity, and Tanner stage in the base models, with additional adjustments for HbA1c, zBMI, lean mass, or percent fat. Results: This subcohort of youth with T2D from the TODAY study included 150 males and 248 females, mean age 13.9 ± 2.0 years. Females had lower zBMI (+2.2 ± 0.4 vs. +2.3 ± 0.5, p=0.005), lower lean mass (51 ± 10 vs. 59 ± 14, p<0.001), and higher percent body fat (39 ± 5 vs. 34 ± 6, p<0.001). Higher log2 GHR was associated with higher zBMI (B=0.44, SE=0.04, p<0.001), higher lean mass (B=4.3, SE=1.2, p<0.001), and higher percent fat (B=4.4, SE=0.7, p<0.001), even after adjustment for HbA1c, and without sex-specific differences. Higher log2 GHR was associated with higher HbA1c (B=0.35, SE=0.08, p<0.001), higher fasting glucose (B=9.0, SE=2.6, p<0.001), lower 1/fasting C-peptide (B=-0.17, SE=0.01, p<0.001), and lower CODI (B=-0.001, SE=0.001, p=0.02). These associations did not change with further adjustments for zBMI, lean mass, or percent fat, suggesting that associations between GHR and glycemia are independent of obesity or body composition. In analyses stratified by sex, the effect of GHR on CODI was attenuated after adjustment for lean mass in males only. Conclusion: Plasma GHR is independently associated with body composition and glycemia in youth with T2D. There were no sex differences in associations of GHR with HbA1c and insulin resistance. However, the association of GHR with beta cell function may be mediated by lean mass in boys but not in girls, although power was more limited in the sex-stratified analyses. Presentation: 6/3/2024

12542 Results Of The Foresight Trial Support The Efficacy And Safety Of Once-weekly Lonapegsomatropin In Adults With Growth Hormone Deficiency (ghd)

Abstract Disclosure: B.M. Biller: Consulting Fee; Self; HRA Pharmaceuticals, Novartis Pharmaceuticals, Sparrow, Strongbridge Biopharma. Grant Recipient; Self; Strongbridge Biopharma. A. Gilis-Januszewska: Speaker; Self; Ipsen, Novartis Pharmaceuticals, Novo Nordisk, Recordati, Teva Pharmaceutical Industries Ltd.. M. Doknic: None. A.M. Pico: None. M. Fleseriu: Consulting Fee; Self; Ascendis, GlaxoSmithKline, Johnson &Johnson, Karyopharm, Novo Nordisk, Pfizer, Inc., Pharmacosmos. Research Investigator; Self; Ascendis. G. Raverot: None. A.M. Isidori: None. Y. Takahashi: None. J.M. Garcia: None. J.M. Silverstein: None. I. Bancos: None. E. Huang: Employee; Self; Ascendis Pharma, Inc. J. Kang: Employee; Self; Ascendis Pharma, Inc. A.S. Komirenko: Employee; Self; Ascendis Pharma, Inc. L. Domrzalski: Employee; Self; Ascendis Pharma, Inc. A. Shu: Employee; Self; Ascendis Pharma, Inc. K. Yuen: Advisory Board Member; Self; Amryt, Ascendis, Corcept, Crinetics, Novo Nordisk, Recordati, Strongbridge, Xeris. Grant Recipient; Self; Amryt, Ascendis, Corcept, Crinetics. Speaker; Self; Corcept, Novo Nordisk, Recordati. Background: Adult GHD (aGHD) is characterized by metabolic abnormalities due to insufficient growth hormone (GH) production. Lonapegsomatropin was designed to provide sustained release of unmodified somatropin, with the identical amino acid sequence as endogenous GH, and once-weekly injection reduces the burden of daily GH replacement therapy. MethodsForesiGHt was a randomized, parallel-3-arm, placebo(PL)-controlled (double-blind) and active-controlled (open-label) trial designed to establish the efficacy and safety of lonapegsomatropin in aGHD. It evaluated 259 adults with GHD across 21 countries who were GH treatment-naïve or not treated with GH in the prior year, randomized 1:1:1 to receive lonapegsomatropin, once-weekly PL, or daily somatropin (dGH). Fixed dosing was based on age and oral estrogen intake, and designed to be comparable across lonapegsomatropin and dGH arms. Following a 12-week (w) titration period to target maintenance dose, fixed doses were administered for 26w. ResultsBaseline (BL) characteristics were similar between arms. Lonapegsomatropin demonstrated superiority on the primary efficacy endpoint of change from BL in trunk percent fat at Week 38 vs PL (lonapegsomatropin -1.7% vs PL 0.4%, LS mean difference -2.0%, p < 0.0001) and on the key secondary efficacy endpoints of change from BL in total body lean mass (lonapegsomatropin 1.6 kg vs PL -0.1 kg, LS mean difference 1.7 kg, p < 0.0001) and change from BL in trunk fat mass (lonapegsomatropin -0.5 kg vs PL 0.2 kg, LS mean difference -0.7 kg, p = 0.0053). Mean total exposure and maintenance doses were similar for lonapegsomatropin and dGH arms, with larger changes from BL in average IGF-I SDS mean at Week 38 in the lonapegsomatropin arm (1.4) vs dGH arm (0.5). To assess outcomes at comparable weekly IGF-I exposure, a post-hoc analysis was performed in a subset of participants with average IGF-I SDS ≤1.75 SDS at Week 38. Mean IGF-I SDS for these subsets were similar (lonapegsomatropin -0.1, dGH -0.5), and comparable effects in fat and lean tissue compartments were demonstrated (change from BL in trunk percent fat mean -2.4% and -2.6% respectively; change from BL in total body lean mass mean 1.7 kg and 1.4 kg respectively). In the safety population, the incidence of severe AEs was low (lonapegsomatropin, 3.4%; placebo, 1.2%; dGH, 2.3%) and the incidence of treatment-related AEs was similar (lonapegsomatropin 24.7%, dGH 22.1%). Injection site reaction incidence was low and similar for lonapegsomatropin (4.5%), dGH (5.8%) and placebo (4.8%), and A1c levels remained stable in all treatment arms. ConclusionsThe results of the foresiGHt trial indicate that lonapegsomatropin is a safe, efficacious, and tolerable replacement for endogenous GH. Once-weekly dosing may be impactful for adults with GHD who typically manage multiple other medical therapies. Presentation: 6/3/2024

8159 Single Nuclei RNA-Sequencing Reveals Novel Cellular Diversity in Human Neck Adipose Tissue

Abstract Disclosure: H. Camara: None. S.D. Kodani: Employee; Self; Hoxton Farm. S. Yang: None. V. Efthymiou: None. K. An: None. A. Gupta: None. F. Shamsi: None. A. Streets: None. M.E. Patti: Advisory Board Member; Self; Fractyl Laboratories. Consulting Fee; Self; AstraZeneca, Hamni, MBX Biosciences. Grant Recipient; Self; Dexcom. Y. Tseng: Consulting Fee; Self; LyGenesis. Other; Self; BioHaven. Adipose tissue plays a crucial role in maintaining metabolic health. It fulfills distinct functions through two types of fat: white adipose tissue (WAT), the primary site of triglyceride storage, and brown adipose tissue (BAT) along with related beige fat, specializing in thermogenic energy expenditure. Despite the scarcity of BAT in humans, these thermogenic adipocytes efficiently utilize glucose and triglycerides and act as an endocrine organ by secreting batokines. Hence, increased BAT activity is associated with improved metabolic health in humans. In adults, thermogenic adipose tissue is localized in deep neck planes, exhibiting a gradient from white to beige/brown from superficial to deep layers. Mounting evidence suggests the diverse cell types within the adipose tissue and their dynamic interactions play an important role in its versatile functions. To understand the cellular compositions of human adipose tissue and directly compare the differences between human BAT vs. WAT, we collected 30 paired samples of superficial, intermediate and deep human neck adipose tissue from 15 participants who underwent anterior cervical discectomy fusion or thyroid surgery and subjected the frozen tissues to single-nucleus RNA sequencing (snRNA-seq). The integration of the samples yielded 41,337 good-quality nuclei. As expected, white adipocytes (WAd) were the dominant cell type, comprising 38% of the total cells captured. Further analysis of the WAd cluster revealed increased expression of brown adipocyte-associated genes, such as EBF2 and COBL, and enrichment of oxidative phosphorylation pathway score in cells from deep neck samples, indicating increased thermogenic potential. Bona fide brown adipocytes (BAds), marked by the expression of PPARGC1A, were predominantly located in the deep neck samples (>80%) but comprised less than 2% of the dataset. Despite their low numbers, cell-cell communication analysis by CellChat predicted that BAds account for most of the communication events within this niche, highlighting their endocrine importance. snRNA-seq also captured non-adipocyte cells, including adipocyte progenitors, smooth muscle, immune, Schwann and neuron-associated cells. Among these, a novel Neuron-Associated Cell-1, marked by the expression of CNTNAP2, emerged as the second most abundant in the dataset (∼10% of total). Another neuron-associated cell population marked by expression of DNAH11, though less abundant (∼1%), was enriched in deep neck samples, potentially regulating the high levels of thermogenic potential in this region. Taken together, the identified subpopulations and their gene expression profiles offer new insights into the tissue's role in metabolic regulation. This knowledge could be pivotal for developing targeted therapies for obesity and related disorders. Presentation: 6/1/2024

8647 Reversal Of Left Atrial Dilation In Heart Failure With Preserved Ejection Fraction (HFpEF) Treated With A GLP-1 Receptor Agonist And A Mineralocorticoid Receptor Antagonist

Abstract Disclosure: M. Marino: None. L.S. Phillips: Advisory Board Member; Self; Diasyst, Inc.. Research Investigator; Self; Abbvie, Research Support, Jansen Pharmaceuticals, Research Support, Novo Nordisk, Research Support, Abbott Laboratories, Research Support, GlaxoSmithKline, Research Support, Sanofi-Aventis, Research Support, Pfizer, Inc.. Background: HFpEF is a major public health problem, since contributors include age, hypertension, hyperglycemia, and inactivity - and the US population is aging, hypertension and hyperglycemia are often inadequately treated, and inactivity is common. Moreover, management is difficult, since few medications have improved outcomes, and there is little long-term experience with sodium-glucose co-transporter-2 (SGLT-2) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, and mineralocorticoid receptor antagonists. Clinical Case: In October 2010, a 69-year-old male with a history of lung adenocarcinoma with left lower lobe segmentectomy, prostate cancer post prostatectomy, and well-managed hypertension and hyperglycemia experienced severe shortness of breath while running on a track as part of his routine exercise. A left heart catheterization was performed to determine if the symptoms reflected inadequate perfusion, revealing only 30% stenosis in the left anterior descending coronary artery, ruling out coronary disease as the primary etiology. However, the left ventricular end diastolic pressure (LVEDP) was elevated (25 mmHg vs. normal <12), indicating heart failure. A transthoracic echocardiogram (TTE) in December 2010 revealed a normal left ventricular ejection fraction (EF 65%), a severely dilated left atrium [left atrial volume index (LAVI) 57 mL/m2 vs. normal <34], and diastolic dysfunction [flow velocity across the mitral valve (E/A ratio 1.61 and E/e’ 7.26). The patient was given pioglitazone 30mg daily before and nebivolol 2.5mg BID after the TTE, but in March 2011, a TTE showed an EF of 57% with persistent left atrial dilation (LAVI 50 mL/m2). A dipeptidyl peptidase-4 (DPP-4) inhibitor (sitagliptin 100mg daily) was begun August 2011, changed to liraglutide 1.8mg daily in December 2011, and eplerenone 75mg daily was begun February 2012. In June 2012, the LAVI was markedly improved (39 mL/m2). The nebivolol was switched to irbesartan 225mg daily in August 2012, and canagliflozin 300mg daily was added September 2013. A repeat TTE in March 2014 found an EF of 60%, and showed that the LAVI had returned to normal (34 mL/m2). During this period, mean blood pressure was 111/67 mmHg, LDL cholesterol 57 mg/dL, and HbA1c 5.4%, indicating that inadequate risk factor management was unlikely to be contributing to the diastolic dysfunction. Presently, the patient takes semaglutide, pioglitazone, telmisartan, empagliflozin, and eplerenone, continues to exercise vigorously, and a recent TTE showed an EF of 62% with mild left atrial dilation (LAVI 36.6). Conclusion: Left atrial dilation was improved after addition of a GLP-1 receptor agonist and a mineralocorticoid receptor antagonist, prior to use of an SGLT-2 inhibitor. Future investigations are needed to further understand the cardiovascular utility of these medications - beyond glycemic control and electrolyte balance. Presentation: 6/3/2024

5043 Skeletal Microstructure in Men with Celiac Disease

Abstract Disclosure: A. Rubenstein: None. A. Kondapalli: None. S. Agarwal: None. M. Bucovsky: None. I. Colon: None. N. Kil: None. S. Lewis: None. B. Lebwohl: None. P. Green: None. M. Walker: Advisory Board Member; Self; Alexion Pharmaceuticals, Inc.. The pathophysiology of osteoporosis related to celiac disease (CD) remains incompletely understood. High resolution peripheral quantitative computed tomography (HRpQCT) has revealed microarchitectural deficits in women with CD, but no data exist in men. We prospectively studied bone health using DXA and HRpQCT in 17 men with duodenal biopsy-confirmed CD (mean age 43±16 years; 82% white, 6% Asian, 12% other) and 5 male controls (mean age 40±12 years; 80% white, 20% Asian). Compared to controls, men with CD had lower self-rated health scores (p<0.05), but age, BMI, alcohol use, physical activity, acid blocker use, and vitamin D intake did not differ. Among patients with CD, 23.5% had other autoimmune diseases (type 1 diabetes, hypothyroidism, vitiligo, systemic sclerosis). At CD diagnosis, mean age was 34.3 ± 14.8. CD patients had a mean CD and gluten-free diet duration of 8 years. 29% of patients (n=5/17) were enrolled within 13 months of CD diagnosis. Mean tissue transglutaminase IgA, serum calcium, PTH, Vitamin D, and alkaline phosphatase were normal, but vitamin D levels were < 30 ng/mL in 36% (n=5/14) and PTH was elevated in 11% (n=1/9). T- (-0.5±1.5 vs. 0.8±0.8, p=0.03) and Z-scores (-0.1±1.4 vs. 1.1±0.9, p=0.05) by DXA were normal at all sites but tended to be lower at the 1/3-radius only in CD compared to controls. By HRpQCT, there were no differences. Compared to a larger control group including HRpQCT data from an additional 14 normative database controls (n=19), CD had lower radial cortical (-4.7%, p=0.02) and tibial trabecular (-13.3%, p=0.04) vBMD and a trend toward lower cortical volumetric BMD (vBMD; -3.5%, p=0.06) at the tibia. Within the CD group, longer CD duration was associated with worse tibial cortical vBMD at (r=-0.55, p=0.02). Higher PTH (n=9) correlated with lower lumbar spine areal BMD (r=-0.75, p=0.02), tibial trabecular thickness (Tb.Th; r=-0.77, p=0.02) as well as radial cortical vBMD (r=-0.81, p<0.01), trabecular Tb.Th (r=-0.78, p=0.01), and cortical thickness (r=-0.75, p=0.02). Those with greater dietary vitamin D intake had higher total vBMD (r=0.50, p=0.04) and trabecular thickness at the tibia (r=0.51, p=0.04). Similarly, higher 25-hydroxy vitamin D levels were associated with higher total hip aBMD (r=0.58, p=0.03). In summary, CD in men is associated with lower areal BMD at the 1/3-radius by DXA and lower vBMD at the radius and tibia by HRpQCT. Low vitamin D levels and secondary hyperparathyroidism may contribute. Further work is needed to understand the extent and pathophysiology of skeletal disease in men with CD. Presentation: 6/3/2024

12418 Patient- And Caregiver-reported Experiences Of Hunger, Weight, And Energy In Acquired Hypothalamic Obesity Before And During Setmelanotide Treatment

Abstract Disclosure: C.L. Roth: Advisory Board Member; Self; Rhythm Pharmaceuticals, Inc. A.H. Shoemaker: Advisory Board Member; Self; Saniona, Rhythm Pharmaceuticals, Inc. Speaker; Self; Saniona, Rhythm Pharmaceuticals, Inc. C. Ervin: Other; Self; Rhythm Pharmaceuticals, Inc. L. Norcross: Other; Self; Rhythm Pharmaceuticals, Inc. S. Fehnel: Other; Self; Rhythm Pharmaceuticals, Inc. C. Huber: Employee; Self; Rhythm Pharmaceuticals, Inc.. Stock Owner; Self; Rhythm Pharmaceuticals, Inc. C. Scimia: Employee; Self; Rhythm Pharmaceuticals, Inc.. Stock Owner; Self; Rhythm Pharmaceuticals, Inc. M.J. Abuzzahab: Consulting Fee; Self; Rhythm Pharmaceuticals, Inc., Ascendis, Novo Nordisk, Lumos, Soleno, Pfizer, Inc.. Speaker; Self; Rhythm Pharmaceuticals, Inc., Ascendis, Novo Nordisk, Lumos, Soleno, Pfizer, Inc.. Background: Acquired hypothalamic obesity (HO) is a rapid-onset, severe obesity caused by hypothalamic injury that may impair melanocortin-4 receptor (MC4R) pathway signaling and lead to hyperphagia, decreased energy expenditure, and severe obesity, for which no approved therapies exist. We describe experiences or caregiver observations of hunger, weight, and energy in patients with HO before and after investigational treatment with the MC4R agonist setmelanotide. Methods: In-depth qualitative interviews were conducted via Zoom by 2 members of the study team with patients or caregivers of patients who completed a Phase 2 trial of setmelanotide (NCT04725240) and enrolled in the open-label long-term extension (NCT03651765). Eligible patients were aged ≥12 years and eligible caregivers were aged ≥18 years and full-time caregivers of patients aged <12 years or unable to self-report. Interview transcripts were analyzed using a thematic approach. Results: Five participants (3 patients, 2 caregivers) completed interviews. After hypothalamic damage (before setmelanotide), all participants described unrelenting hunger, drastically reduced energy or physical activity, and substantial weight gain negatively impacting self-esteem, emotions, and family dynamics. With setmelanotide, all participants reported reduced weight or body mass index, and 4 reported reduced hunger, which was accompanied by improved food-seeking behaviors, sleep (eg, not waking at night for food), self-confidence, and mood. Participants identified reduced hunger and weight and improved emotions or mood as the most important treatment benefits. Additional benefits were improved social engagement, physical activity, and school/work performance. All reported satisfaction and a desire to continue setmelanotide. Conclusions: Patients experienced negative consequences of hypothalamic damage on hunger, weight, and energy that were alleviated by setmelanotide, resulting in broad benefits for patients and caregivers. Presentation: 6/1/2024

8604 Ectopic Cushing’s Syndrome Associated with a Metastatic Pancreatic Mixed Neuroendocrine Non-neuroendocrine Neoplasm (MiNEN) with Amphicrine Features

Abstract Disclosure: A. DeMarsilis: None. C. Jiang: None. O. Lavrynenko: None. D. Motavalli: None. C. Musurakis: None. Z.H. Taxin: None. E.D. Rosen: Advisory Board Member; Self; Source Bio, Inc.. Consulting Fee; Self; Novartis Pharmaceuticals, Gensaic. M.S. Irwig: None. Background: Ectopic Cushing’s Syndrome (CS) makes up 9-18% of ACTH-dependent CS cases, of which fewer than 15% are attributed to pancreatic neuroendocrine tumors (1). Mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs) are rare, aggressive carcinomas, often driven by high-grade neuroendocrine components, with a poor prognosis (2). Amphicrine neoplasms contain neuroendocrine and exocrine components in the same cell. Clinical Case: A 34 year-old woman with asthma, hypertension, and depression presented with new onset lower extremity edema, facial hirsutism, mood changes, polyuria and polydipsia. She had an elevated morning serum cortisol of 52 ug/dL (normal < 20) with plasma ACTH 42 pg/mL (normal < 50), 24-hour urine free cortisol of 1003 mcg (normal < 50), K+ of 2.6 mEq/L, and fasting glucose 164 mg/dL. CT showed multiple hepatic lesions, pulmonary nodules, a pancreatic tail lesion, and lymphadenopathy concerning for metastatic disease. Her adrenal glands were thickened bilaterally without nodules. A pituitary MRI was normal. These findings were concerning for ectopic CS. She was admitted due to rapidly developing symptoms. Potassium, insulin, sitagliptin, and prophylactic anticoagulation were started. Spironolactone and ketoconazole were initiated while awaiting biopsy results of liver and pancreas lesions. Osilodrostat was not available and a trial of metyrapone was poorly tolerated. The liver and pancreatic tail lesion biopsy revealed metastatic MiNEN with amphicrine features, of pancreatic origin, with Ki67 proliferation index of 70%. Section staining of pancreas and liver biopsies were negative for ACTH. A Ga-68 Dotatate scan showed minimal uptake, so octreotide was not prescribed. Palliative chemotherapy was planned. Although ketoconazole was titrated to 1600 mg/day, urine free cortisol levels and serum free cortisol levels did not reach target. Cushing disease was considered but not suspected, as ACTH levels remained modest despite a relative decrease in cortisol level. Given significant morbidity from uncontrolled hypercortisolism, and plans for urgent initiation of systemic chemotherapy, after multidisciplinary discussion the patient was treated with a surgical bilateral adrenalectomy. Post-operative morning serum cortisol measured 8.3 ug/dL. After one week, palliative chemotherapy with FOLFIRINOX (oxaliplatin, leucovorin, fluorouracil, and irinotecan) was initiated. She was discharged home on stress dose steroids with plan for taper. Conclusion: Ectopic ACTH secretion is a rare phenomenon, particularly when presenting with a rare case of metastatic pancreatic MiNEN with amphicrine features, associated with significant morbidity. To improve tolerance and survival of further treatment, early surgical bilateral adrenalectomy should be considered.

7010 The Incidence Of Cushing Syndrome In Wisconsin Is More Common Than Population-Based Studies From Europe

Abstract Disclosure: T. Matoska: None. T.B. Carroll: Consulting Fee; Self; Corcept Therapeutics. Research Investigator; Self; Corcept Therapeutics. T.S. Wang: None. S. Dream: None. N. Zwagerman: None. J.W. Findling: Advisory Board Member; Self; Corcept Therapeutics, Recordati, Diurnal. Introduction: Endogenous neoplastic hypercortisolism [Cushing syndrome (CS)] is considered to be a rare disorder. Population-based studies from Europe estimate the incidence of CS to range from 1.8-3.2 cases/million patient-years, and there is limited data reporting the incidence of CS in the United States. All previous studies have shown that pituitary ACTH secreting tumors [Cushing disease (CD)] are the most common cause of CS. Based on our clinical experience, we speculated that the incidence of CS was more common than reported and that adrenal CS (ACS) was more common than CD. This study reports the incidence and etiology of CS from a single tertiary care center in Wisconsin (WI). Methods: Institutional clinic records between May 1, 2017, and December 31, 2022, were queried to identify WI residents treated for CS. Only patients diagnosed and treated at our institution during the study period were included. The diagnosis of CS was established with standard guideline-supported biochemical testing and appropriate imaging. Patients diagnosed with exogenous CS and those who did not undergo therapy for CS were excluded. Results: The query identified 185 patients who were diagnosed and treated for CS. These patients resided in 27 of the 72 WI counties representing a population of 4.5 million of the total WI population of 5.9 million. This suggests that, at a minimum, the incidence of CS in WI is 7.2 cases/million patient-years. Moreover, data from the WI Hospital Association show our institution treated <50% of all patients with CS discharged from WI hospitals from 2019-2023. Mean age at diagnosis was 52.4 years (SD 14.7) and 135 (73%) were female. Of the total cohort, 111 (60%) had ACS, 68 (36.8%) had CD, and 6 (3.2%) had ectopic ACTH syndrome (EAS). Patients with ACS had significantly lower LNSC, DST cortisol, and UFC when compared to those with CD and EAS. ACS had mean (SD) LNSC, DST cortisol, and UFC of 0.236 µg/dL (0.367), 6.5 µg/dL (8.7), and 64.2 µg/24h (92.8), respectively. CD had mean (SD) LNSC, DST cortisol, and UFC of 0.425 µg/dL (0.403), 11.7 µg/dL (7.5), and 151.1 µg/24h (287.4), respectively. EAS had mean (SD) LNSC, DST cortisol, and UFC of 3.189 µg/dL (0.931), 42.5 µg/dL (40.5), and 1514.2 µg/24h (1278.9), respectively. Overt physical features of CS were documented in the medical record of 117 (63.2%) patients at diagnosis ((ACS: 49 (44%); CD: 62 (91%); EAS: 6 (100%)). Conclusion: This study suggests that ACS is more common than CD as a cause of CS, and patients with ACS more frequently presented without physical features of hypercortisolism, probably due to the milder degree of cortisol excess. The incidence of CS in WI is at least 7.2 cases/million patient-years. As our institution cares for <50% of patients with CS in WI, the true incidence is likely far greater and may approach 14-15 cases/million patient-years. Presentation: 6/1/2024

6612 Both Overt And Mild Hypercortisolism Accelerate Biological Aging

Abstract Disclosure: K. Yu: None. J. Saini: None. J.N. Farr: None. F. Vanessa: None. S. Khosla: None. I. Bancos: Advisory Board Member; Self; AstraZeneca, Adrenas, Neurocrine, Spruce, Recordati, Xeris, Novo Nordisk, HRA Pharmaceuticals, Sparrow, Diurnal, Corcept. Research Investigator; Self; HRA Pharmaceuticals, Recordati. Importance: Patients with both mild autonomous cortisol secretion (MACS) and overt Cushing syndrome (CS) demonstrated high prevalence of aging-related morbidity and an increased mortality. Objective: To determine whether p16INK4a in T cell, a cell cycle enzyme that associated with chronological aging and cell senescence, is associated with hypercortisolism and hypercortisolism-related comorbidities. Design, Setting, and Participants: In this single-center cross-sectional study, we prospectively recruited consecutive patients with hypercortisolism between July 1, 2020 and August 24 2022. Patients were included if they were diagnosed with Cushing syndrome (CS) or mild autonomous cortisol secretion (MACS). Age- (± 2 years) and sex-matched referent subjects without known adrenal disorders were included if abdominal imaging was available. Participants on exogenous glucocorticoids within 3 months prior were excluded. Exposure: Presence of hypercortisolism (MACS and CS). Main Outcomes and Measures: Primary outcomes included p16INK4a, advanced glycation end products (AGE) reader result, Frailty Index score, frailty (defined as frailty index>0.31), and physical performances in patients and matched referents at index date. Secondary outcomes included correlation between biological age markers, hormonal workup and the risk of comorbidities. p16INK4a expression analysis was adjusted for age, sex, smoking, and alcohol use for all analyses except for associations with CVD and frailty. Results: Of 85 patients (87% women, mean age 53 years), 51 (60%) had MACS (34 had matched referents), 34 (40%) had overt CS (16 had matched referents). Patients with CS demonstrated a median 1.9-fold higher p16INK4a expression (P<.001), and patients with MACS showed a median of 1.70-fold p16INK4a expression (P=.013), when compared to referent subjects. Age- and sex-adjusted p16INK4a expression was associated with frailty index score (r=0.23, P=.035), time-up-and-go test (r=0.28, P=.048), gait speed (r=-0.36, P=.035), but not with AGE reader result, 6-minute walk test, or hand grip measurement. The p16INK4a expression was associated with history of cardiovascular disease (age-adjusted odds ratio (aOR)=3.70, 95% confidence interval (CI), 1.20-11.43) and frailty (aOR=2.27, 95%CI, 1.04-4.98). Conclusion and relevance: We demonstrated evidence of cell senescence in both patients with CS and patients with MACS. Further studies need to determine the impact of surgical, cortisol-lowering, and senolytic medical therapies in MACS on cell senescence and associated aging-related comorbidities. Presentation: 6/1/2024

5065 Cyproterone Acetate Versus Spironolactone In Transgender Women Commencing Estradiol: A Randomized Controlled Trial

Abstract Disclosure: L.M. Angus: Advisory Board Member; Self; Kirin Brewery. Speaker; Self; Kirin Brewery. S. Leemaqz: None. A. Kasielska-Trojan: None. M. Mikołajczyk: None. J. Doery: None. J.D. Zajac: None. A.S. Cheung: None. Background: Transgender women commonly use cyproterone acetate or spironolactone as anti-androgens with estradiol to assist with feminization. However, the optimal anti-androgen is unclear. We aimed to assess the effect of these anti-androgens on breast development and hypothesized that cyproterone acetate would result in greater breast development than spironolactone due to greater androgen receptor antagonism and suppression of serum total testosterone. Design: Double-blind, randomised controlled trial Methods: Transgender women newly commencing estradiol were randomized to spironolactone 100mg daily or cyproterone acetate 12.5mg daily for six months. The primary outcome was measurement of breast development via breast chest distance with secondary outcomes of estimated breast volume using the BreastIdea Volume Estimator application and serum total testosterone using LCMS. Results: Fifty-five participants were included in per protocol analysis (cyproterone acetate group n=28, spironolactone group n=27). Baseline age, body mass index, breast indices, serum estradiol and serum total testosterone were comparable. At six months, the mean (standard deviation) breast chest distance was 9.2cm (3.0) in the cyproterone group versus 8.3cm (2.7) in the spironolactone group (p=0.27). The mean (SD) estimated breast volume was 190.25 mL (158.60) in the cyproterone acetate group and 157.84mL (112.03) in the spironolactone group (p=0.39) with significant inter-individual variation (range 20.27 - 787.77 mL). The mean (SD) serum total testosterone was 1.48 nmol/L (3.45) in the cyproterone acetate group and 4.29 nmol/L (5.44) in the spironolactone group (p=0.04). Serum estradiol levels were comparable. Use of cyproterone acetate was associated with mild hyperprolactinaemia and spironolactone with an increase in serum urea and creatinine. Conclusions: Choice of anti-androgen should be individualised based on clinician and patient preference, with consideration of associated side effects. Further research is needed to optimise breast development in transgender women. Presentation: 6/3/2024

12497 Stage 1 Results Of The Phase 2 Daybreak Trial Assessing Setmelanotide In Patients With Early-onset, Severe Obesity And Hyperphagia Who Carried A Confirmed Variant Related To The Melanocortin-4 Receptor Pathway

Abstract Disclosure: G. Ortiz: Speaker; Self; Rhythm Pharmaceuticals, Inc. S.B. Ten: Advisory Board Member; Self; Rhythm Pharmaceuticals, Inc. Speaker; Self; Rhythm Pharmaceuticals, Inc. W. Herring: Advisory Board Member; Self; Rhythm Pharmaceuticals, Inc, Novo Nordisk. O. Pinhas-Hamiel: None. E.A. Oral: Consulting Fee; Self; Rhythm Pharmaceuticals, Inc., Akcea Therapeutics, Ionis Pharmaceuticals Inc., Morphic Medical, Fractyl Laboratories, Regeneron Pharmaceuticals, Amryt Pharmaceuticals (now Chiesi), Third Rock Ventures, Rejuvenate Bio, NIDDK. Other; Self; Has patents for use of metreleptin in lipodystrophy and recombinant leptin or analogues in NASH. N. Rosano: Consulting Fee; Self; Novo Nordisk. Speaker; Self; Rhythm Pharmaceuticals, Inc. D. Koren: Employee; Self; Rhythm Pharmaceuticals, Inc.. Stock Owner; Self; Rhythm Pharmaceuticals, Inc. H. Lee: Employee; Self; Rhythm Pharmaceuticals, Inc.. Stock Owner; Self; Rhythm Pharmaceuticals, Inc. J. Garrison: Employee; Self; Rhythm Pharmaceuticals, Inc.. Stock Owner; Self; Rhythm Pharmaceuticals, Inc. O. Ohayon: Employee; Self; Rhythm Pharmaceuticals, Inc.. Stock Owner; Self; Rhythm Pharmaceuticals, Inc. P. Sleiman: Employee; Self; Rhythm Pharmaceuticals, Inc.. Stock Owner; Self; Rhythm Pharmaceuticals, Inc. M. Wabitsch: Consulting Fee; Self; Rhythm Pharmaceuticals, Inc.. Speaker; Self; Rhythm Pharmaceuticals, Inc.. Other; Self; Rhythm Pharmaceuticals, Inc. E. van den Akker: Speaker; Self; Federatie Medisch Specialisten, Stichting Kwaliteitsgelden Medisch Specialisten, Medialane TV, Pfizer, Inc.. Other; Self; Nederlandse Hartstichting/ZonMW, Stichting Erasmus Trustfonds, Rhythm Pharmaceuticals, Inc. J. Argente: Advisory Board Member; Self; Rhythm Pharmaceuticals, Inc. Speaker; Self; Rhythm Pharmaceuticals, Inc.. I. Farooqi: None. Background: DAYBREAK (NCT04963231) was designed to evaluate setmelanotide in individuals who carried a confirmed variant in ≥1 of 31 genes with strong or very strong relevance to the melanocortin-4 receptor (MC4R) pathway, which regulates energy balance and satiety. Methods: DAYBREAK is a 2-stage, double-blind, placebo-controlled trial conducted at 37 sites across 8 countries. Individuals aged 6 to 65 years with body mass index (BMI) ≥40 kg/m2 (aged ≥18 years) or ≥97th percentile (aged ≥6 to <18 years) and hyperphagia who carried variants classified as uncertain significance (VUS), likely pathogenic, or pathogenic according to the American College of Medical Genetics (ACMG) criteria in ≥1 of the 31 genes were eligible. Individuals with ≥5% BMI reduction from baseline (ie, responders) at the end of the 16-week, open-label run-in period (Stage 1) were eligible to enter a 24-week, double-blind, randomized, placebo-controlled period (Stage 2). The primary endpoint of Stage 1 was the proportion of responders per gene cohort at the end of the Stage. Results: A total of 164 individuals were enrolled; 100 patients who completed Stage 1 and 12 who discontinued treatment within a prespecified 2 weeks before the end of Stage 1 were included in the completers analysis. Participants were divided into 15 gene cohorts; of 7 cohorts with ≥5 patients, 6 (SEMA3[A-G], PLXNA[1-4], PHIP, TBX3, MAGEL2, and SIM1) showed potential setmelanotide efficacy (KSR2 did not). Response rates across cohorts (range, 25.0%-56.3%), intracohort response magnitudes (percent BMI change from baseline to Week 16; range, −6.4% to −4.0%), and intracohort variant types varied. While response rate was highest in the PHIP cohort (56.3% of the full cohort and 69.2% of completers), ≥1 patient per cohort achieved ≥10% BMI reduction. Because ∼80% of VUS are eventually reclassified to benign or likely benign, the inclusion of VUS may have contributed to response variability. An ad hoc analysis showed an increased response rate with updated versus starting ACMG variant classification. Overall, 49 responders across 6 gene cohorts were randomized into Stage 2. Setmelanotide was well tolerated with no new safety concerns. Conclusions: DAYBREAK Stage 1 identified 6 additional genes or gene families in the MC4R pathway that respond to setmelanotide. Response was associated with predicted variant pathogenicity, allowing for further refinement of patient selection. Stage 2 results will further elucidate Stage 1 findings. Presentation: 6/3/2024

12362 Pathophysiology From Oxidative Stress Effectively Monitored In A Pre-clinical Model Of Type 2 Diabetes (T2D) With Point-of-care Microscale Magnetic Resonance (µNMR)

Abstract Disclosure: A.T. Alves: ; Co-Founder. ; Self. ; LarmorBio. S.S. Thamarath: ; Co-Founder. ; Self. ; LarmorBio. S. Fjordside: Employee; Self; Novo Nordisk. S. Sassower, MS.EE: ; Co-Founder. ; Self. ; LarmorBio. J. Han: None. L. Bouchard: Advisory Board Member; Self; LarmorBio. R. Rohr, BS.EE: ; Co-Founder, CEO. ; Self. ; LarmorBio. A.P. Chambers: Employee; Self; Novo Nordisk. The declining age of onset of T2D is a vital factor influencing its prospective burden. An early manifestation of the disease leads to an extended duration, which amplifies and accelerates the risk of micro and macrovascular complications. Oxidative stress is a major driver in the pathogenesis of T2D. Early detection and prevention of oxidative stress overload can improve and potentially modify the long-term harmful outcomes of metabolic diseases, including chronic hyperglycaemia.A novel µNMR assay was developed to monitor oxidative stress from minimally invasive plasma samples at the point of care. This approach is highly sensitive to redox changes in the blood microenvironment, including increased ferric iron (Fe3+), protein oxidation, and lipid peroxidation[1]. We hypothesized that oxidative stress would increase significantly faster in the disease group, enabling disease progression monitoring throughout the study and near real-time subject risk stratification based on the core pathophysiology of the diabetic phenotype.This 15-week longitudinal study (6th - 21st week of age) quantified oxidative stress in db/db and db/+ mice (n = 15 per group), accompanied by HbA1c, blood glucose (BG), and body weight (BW). The assay detailed separation (P ≤ 0.01) between the db/db and db/+ mice from the onset of the diabetic phenotype of db/db at 10 weeks of age (mean HbA1c = 6.5%). The oxidative stress monitored continued to increase in the subsequent weeks, where the HbA1c of db/db mice reached maximum (mean HbA1c = 8.8%). The definition of good (HbA1c ≤ 8) and poor (HbA1c > 8) glycaemic control was defined where sub-stratification (P ≤ 0.05) was achieved. Furthermore, the assay highlights a positive correlation with BW (ρ+/db = 0.52, P ≤ 0.0001, ρdb/db = 0.57, P ≤ 0.0001). In the two groups of mice, a positive correlation of oxidative stress with HbA1c (ρ = 0.58, P ≤ 0.0001) and BG (ρ = 0.47, P ≤ 0.0001) was reported. During the 15-week study, the control db/+ group exhibited a 13% mean increase in oxidative stress. In contrast, the db/db group demonstrated a cumulative 20% increase. Notably, considering the diabetic phenotype of the db/db mice, we quantified oxidative stress attributed to aging at 13%.In view of changing diabetes demographics, a multimodal approach of targeted sub-phenotype treatment combined with advanced metabolic monitoring may provide holistic, clinically relevant information to reduce the micro and macrovascular burden of diabetes. In summary, the µNMR assay is an effective method for real-time monitoring of oxidative stress assessment in metabolic disease research and opens new possibilities for cardiometabolic risk assessment and targeted interventions.(1) Peng, W.K. et.al., npj Aging Mech Dis 2020, 6, 11 Presentation: 6/1/2024

7425 Biochemical Response, Symptom Control, and Safety of Oral Octreotide Capsules Treatment in Acromegaly: A Post Hoc Analysis of a Large Pooled Database from Three Phase 3 Clinical Trials

Abstract Disclosure: M. Fleseriu: Consulting Fee; Self; Novo Nordisk, Amryt Pharma Holdings Ltd, Ascend Therapeutics (A Besins Healthcare company). Speaker; Self; Xeris Pharmaceuticals, Inc., RECORDATI_RARE_DISEASES_INC., Ipsen Pharma SAS. S.L. Samson: Advisory Board Member; Self; Amryt. Research Investigator; Self; Amryt. N. Biermasz: Advisory Board Member; Self; Recordati, Pfizer Global R&D. Grant Recipient; Self; Macro Registry Grant, Amryt. C.J. Strasburger: Advisory Board Member; Self; Sandoz, Ipsen, Recordati. Consulting Fee; Self; Ascendis, Amryt, Novo Nordisk, Merck, Sandoz, Recordati. Speaker; Self; Ipsen, Novo Nordisk, HRA-Pharma. S. Fuchs Orenbach: Employee; Self; Chiesi Global Rare Diseases. J.A. Crompton: Employee; Self; Chiesi Global Rare Diseases. S. Melmed: Advisory Board Member; Self; Ionis, Crinetics. Consulting Fee; Self; Ipsen. Grant Recipient; Self; Pfizer. Background: Treatment with oral octreotide capsules (OOC) was evaluated in three phase 3 trials (CH-ACM-01, OPTIMAL, MPOWERED) in patients with acromegaly who previously tolerated and responded to the injectable somatostatin receptor ligands (iSRLs) octreotide and lanreotide. Results demonstrated efficacy and safety despite differences in trial design. Pooling data from all three trials can provide further insight into the biochemical response, symptom improvement, and safety profile of OOC. Objective: Analyze the biochemical changes, symptom control, and safety of OOC through a pooled analysis of phase 3 clinical trial datasets. Methods: Patients included were aged ≥18 years with acromegaly and responded biochemically to iSRL therapy before the initiation of OOC (defined as IGF-I <1.3 × ULN and mean integrated GH <2.5 ng/mL for CH-ACM-01 and MPOWERED, and IGF-I ≤1.0 × ULN for OPTIMAL). Data analyzed were from the following periods: baseline until the end of the double-blind placebo-controlled phase of OPTIMAL (36 weeks); the run-in phase of MPOWERED (26 weeks); end of dose escalation (2-5 months; efficacy data) and end of fixed dose phase (up to 7 months, safety data) for CH-ACM-01. Effect of prior iSRL dose was analyzed using a random effects meta-analysis. Symptom severity was scored using the Acromegaly Index of Severity (AIS) tool. Results: Efficacy, symptom, and safety data were available for 318, 194, and 329 patients, respectively. The overall response rate was 65% with no effect of prior iSRL dose (p>0.05). Mean (SD) IGF-I change from baseline was +0.17 (0.32; n=214), +0.19 (0.39; n=81), and +0.22 (0.57; n=23) for patients with baseline IGF-I levels ≤1 × ULN, 1 to <1.3 × ULN, and ≥1.3 × ULN. Twenty percent (16/81) and 35% (8/23) of patients with baseline IGF-I of 1 to <1.3 x ULN and ≥1.3 x ULN shifted to an improved category of response. There was a median decrease of one symptom per patient (p<0.05) and a mean decrease of 0.8 in AIS (p<0.05). The proportion of OOC responders reporting ≤1, 2, or 3 moderate/severe acromegaly symptoms at baseline and month 6 decreased from 56% to 39%, 32% to 20%, and 20% to 12%. At month 6, improvement was seen for all individual symptoms (joint pain, swelling, sweating, fatigue, headache) of moderate/severe grade and was significant for joint pain (36% to 22%) and swelling (15% to 10%) (p<0.02). Most adverse events (AEs) were gastrointestinal (GI) in nature (54%, n=179/329) with a median onset and duration of 15 and 12 days for first reported GI events. Conclusion: Pooled analysis confirms overall maintenance of biochemical control in patients previously responding to iSRL therapy, with decreased symptom burden in OOC responders. OOC was generally well tolerated with no new safety signals. GI-related AEs were largely transient. These results support OOC as a therapeutic option for treating acromegaly. Presentation: 6/3/2024

6989 Novel Use of Dual GIP/GLP-1 Receptor Agonist in HNF4A-MODY

Abstract Disclosure: A. Mehdi: None. M.C. Foss de Freitas: Advisory Board Member; Self; PTC Pharmaceuticals. Other; Self; Scientific presenter in a symposium funded by Amryt Pharmaceuticals. C.L. Martin: None. B.E. Gregg: None. N. Nachawi: None. E. Frontera: None. E.A. Oral: Consulting Fee; Self; Amryt Pharmaceuticals, Akcea Therapeutics, Ionis Pharmaceuticals Inc., Regeneron Pharmaceuticals. Grant Recipient; Self; Amryt Pharmaceuticals (now part of Cheisi, manufacturer of metreleptin), Akcea Therapeutics, Ionis Pharmaceuticals Inc., Regeneron Pharmaceuticals, Novo Nordisk, Rhythm Pharmaceuticals, Fractyl Laboratories, GI Dynamics (now Morfic Medical. Other; Self; Royalty rights from the use of Metreleptin in lipodystrophy. W.H. Herman: Advisory Board Member; Self; Member of the Data Safety and Monitoring Board for Merck Sharp & Dohme, LLC, Memer of the Data Safety and Monitoring Board for Rivus Pharmaceuticals. Other; Self; Chair for the National Committee for Quality Assurance (NCQA) Healthcare Effectiveness Data and Information Set (HEDIS) Workgroup. D.T. Broome: Consulting Fee; Self; Tayco, Inc. Research Investigator; Self; Novo Nordisk, Fractyl Laboratories, Rhythm Pharmaceuticals, Inc. HNF4A-MODY (formerly MODY-1) is an autosomal dominant form of diabetes caused by a mutation in the transcription factor HNF4A[1],2. Affected patients are initially very sensitive to the anti-hyperglycemic effect of sulfonylureas, but become unresponsive to sulfonylureas at a rate of 1-4% per year3. Recently, the efficacy of glucagon-like peptide-1 receptor agonists has been demonstrated in HNF4A-MODY2, but there have been no reports on the use of dual gastric inhibitory polypeptide/glucagon-like peptide-1 receptor agonists (dual GIP/GLP-1 RA) in HNF4A-MODY. This report describes a patient with HNF4A-MODY who was treated with a dual GIP/GLP-1 RA. A 42-year-old White male with a pathogenic heterozygous mutation in Q268X was diagnosed with HNF4A-MODY at the age of 10 years (part of the RW pedigree)3. He was diagnosed with diabetes at age 20, treated with metformin from age 20 to age 30, and had glipizide extended release added at age 30. His dose of glipizide was titrated over 9-years to the maximum therapeutic dose. At the age of 40, when his HbA1c was no longer controlled, dulaglutide 1.5 mg once weekly was added. Thereafter, his HbA1c was well controlled between 5.5-7.0%, until it increased to 7.7%. He was then transitioned from dulaglutide to tirzepatide 5 mg once weekly for 4 weeks, 7.5 mg once weekly for 4 weeks, then 10 mg once weekly. He has been maintained on tirzepatide 10 mg once weekly, glipizide extended release 10 mg once daily, and metformin 1,000 mg twice daily without significant side effects. His HbA1c improved from 7.7% to 5.8% and he lost 7 lbs since transitioning from dulaglutide to tirzepatide (while on tirzepatide for 4 months in total). During his recent visit, he was without significant hyper- or hypoglycemia and his BMI was 31.2 kg/m2. (down from 32.32 kg/m2). To our knowledge, this is the first case report demonstrating preliminary efficacy of dual GIP/GLP-1 receptor agonist in HNF4A-MODY. While it is known that GIP and GLP-1 can cause glucose stimulated insulin secretion, and the mechanism of GLP-1 was previously described in MODY4, the differential effects and/or predominance of GIP or GLP-1 in MODY requires further investigation.

6820 Assessing The Efficacy And Safety Of Setrusumab For Osteogenesis Imperfecta: Updated Phase 2 Data From The Phase 2/3 Orbit Study

Abstract Disclosure: G.S. Gottesman: Advisory Board Member; Self; Ultragenyx, Kyowa Kirin, Inc. Consulting Fee; Self; Ultragenyx. Research Investigator; Self; Alexion Pharmaceuticals, Inc., Ultragenyx. T.O. Carpenter: Advisory Board Member; Self; Ultragenyx. Consulting Fee; Self; Ultragenyx. Research Investigator; Self; Ultragenyx. M. Wallace: Advisory Board Member; Self; Ultragenyx. Consulting Fee; Self; Novosteo. P. Smith: Grant Recipient; Self; Ultragenyx. Research Investigator; Self; Ultragenyx. E.A. Imel: Consulting Fee; Self; Ultragenyx. Grant Recipient; Self; Ultragenyx. Research Investigator; Self; Ultragenyx. H. Wang: Employee; Self; Ultragenyx. Stock Owner; Self; Ultragenyx. H.M. Byers: Employee; Self; Ultragenyx. Stock Owner; Self; Ultragenyx. S. Krolczyk: Employee; Self; Ultragenyx. Stock Owner; Self; Ultragenyx. E.M. Lewiecki: Consulting Fee; Self; Amgen Inc, Radius Health, Inc. Grant Recipient; Self; Amgen Inc, Radius Health, Inc, Ultragenyx. Research Investigator; Self; Amgen Inc, Radius Health, Inc, Ultragenyx. Speaker; Self; Amgen Inc, Kyowa Kirin, Inc. Osteogenesis imperfecta (OI) is a rare genetic disorder characterized by bone fragility and low bone mass with no universally accepted treatment. Setrusumab is a fully human anti-sclerostin monoclonal antibody that improved bone mineral density (BMD), bone strength, and bone turnover markers in adults with OI (ASTEROID; NCT03118570). In the ongoing Phase 2/3 Orbit study (NCT05125809), Phase 2 evaluated the efficacy and safety of setrusumab in pediatric and young-adult cohorts with OI based on PK/PD, safety, and BMD data, to determine the dosing strategy for the Phase 3 portion. Subjects with OI Types I, III, or IV, ages 5 to <26 years, were randomized 1:1 to receive 20 or 40 mg/kg setrusumab intravenously monthly. Six-month data as of August 2023 are presented. Twenty-four subjects (50% female, 75% <18 years of age) with OI Type I (n=17/24, 71%) or III/IV (n=7/24, 29%) were enrolled and randomized to receive 20 mg/kg (n=14/24) or 40 mg/kg (n=10/24) of setrusumab. The mean (SD) baseline-corrected area under the effect curve (AUEC) for serum P1NP in the 20 mg/kg setrusumab group was 4153 (4407) µg/(L*day) over month one of treatment, and 5256 (5521) µg/(L*day) in the 40 mg/kg group. Mean (SE) change from baseline in lumbar spine BMD in the 20 mg/kg group was 9.1% (1.8%) and 12.8% (2.5%) at M3 and M6, respectively (all p<0.05 vs baseline) and 9.3% (2.4%) and 16.1% (3.9%) in the 40 mg/kg group (M6 p<0.05 vs baseline). Mean (SE) baseline BMD Z-score in the 20 mg/kg group of 2.1 (0.8) improved by 0.6 (0.8) at M3 and 0.9 (0.8) at M6, and improved from 1.1 (0.4) at baseline by 0.5 (0.4) and 0.9 (0.4) at M3 and M6, respectively, in the 40 mg/kg group (all p<0.05 vs baseline). The median annualized fracture rate (excluding fingers, toes, face, and skull) was reduced significantly from 0.7 to 0 (p=0.042) after setrusumab initiation (calculated reduction of 67%). No new radiographically confirmed fractures excluding fingers, toes, face, and skull were reported in 20/24 (83%) subjects after starting setrusumab, while only 4/24 (17%) reported fractures (precipitating events: one subject: slipped on ice, stubbed toe, one subject each: fell off of tricycle, bending over in bed, tripped and fell). Setrusumab treatment resulted in no unexpected adverse events. Treatment-related adverse events included infusion-related reaction (7/24, 29%), headache (3/24, 13%) infusion site pain, bone pain, and upper respiratory tract infection (each 1/24, 4%). In Orbit Phase 2, we observed significant improvements from baseline in lumbar spine BMD at M3 and M6 at both 20 and 40 mg/kg doses, with no marked differences between dose groups. Fracture rates significantly decreased with setrusumab initiation, with 83% of subjects reporting no new fractures. Presentation: 6/1/2024

12459 Exceptional Response To A Single Dose Of Pembrolizumab As Salvage Therapy In A Patient With Metastatic Adrenocortical Carcinoma (ACC)

Abstract Disclosure: L. Branchaud-Croisetière: None. J. Castilloux: None. E. Turcotte: None. A. Bégin: None. M. St-Jean: Advisory Board Member; Self; GlaxoSmithKline, HRA Pharmaceuticals. Research Investigator; Self; AstraZeneca, Novo Nordisk, Spruce Biosciences. Speaker; Self; GlaxoSmithKline, Recordati Rare Diseases. In advanced ACC, limited effective treatment options are available beyond mitotane and cytotoxic chemotherapy. PD-L1 blockade has shown promising results in small numbers of advanced ACC. In ACC, the reported partial response rate to pembrolizumab is around 25%.[1] Only one case of a significant partial response to a single dose of Pembrolizumab as salvage therapy for metastatic ACC was previously published.[1] In April 2023, a 19-year-old woman presented with severe hypertension, hypokalemia and clinical signs of Cushing syndrome (CS). Thoraco-abdominal scan revealed a left-sided cluster of confluent adrenal masses (7.3 x 14.4 x 11.4 cm), a left cortical renal lesion (2.8x2x2.1cm), a right ovarian teratoma (7.9 x 7.8x7.9 cm) and at least 25 pulmonary micronodules. FDG-PET SCAN revealed a significant hypermetabolism of the left adrenal lesions (SUV 18.6), ovarian teratoma (SUV 5.5) and pulmonary micronodules (SUV 1.1-2). Cortisol and androgens secretion was confirmed biochemically. Initially, she was not candidate for a debulking surgery because the tumor was surrounding the aorta, and mesenteric arteries. Hypertension and hypokalemia were treated with spironolactone, amlodipine, amiloride and irbesartan. Cushing syndrome was treated with metyrapone. In April 2023, Etoposide-Doxorubicine-Cisplatin (EDP) was administered in combination with Mitotane (max: 8g/day). After 6 cycles of EDP-M the disease regressed slightly but was considered stable based on RECIST criteria. After 8 cycles, the follow-up imaging showed a progression of the adrenal lesion (9.2x18.2cm) but stable pulmonary micronodules. A biopsy of the adrenal lesion, for therapeutic purpose, revealed microsatellite stability (MSS). The patient refused germinal genetic testing. It was decided in multidisciplinary tumor board to try Pembrolizumab. In December 2023, she received one cycle of Pembrolizumab (140mg), but the treatment was complicated by grade 4 immune-mediated hepatitis. A few weeks following Pembrolizumab she completely normalized her blood pressure and hypokalemia despite cessation of all her anti-hypertensive drugs. Pembrolizumab and Mitotane were stopped and hepatitis completely resolved after two months of Mycophenolate Mofetil and ongoing decreasing dose of prednisone. In March 2024, CT scan showed a 60% regression of the adrenal mass (4.1 x 7.2 cm), stability of the renal lesion and ovarian teratoma and complete resolution of the pulmonary micronodules. We suspect an ongoing effect of immunotherapy and Mitotane, since Mitotane levels were still in the therapeutic range (15.1 mg/L) six weeks following cessation. Mitotane was resumed in March 2024. The patient will potentially have a resection of the left adrenal lesion in the next month. This is second published case of a significant response to Pembrolizumab as second-line therapy for advanced ACC. [1] Raj Net al. J Clin Oncol. 2020 Presentation: 6/1/2024