{"id":81,"slug":"81-semaglutide-n-terminal-conjugation-of-a-short-discrete-peg2-8-amino-3-6-","title":"N-terminal PEG2 spacer + His-1 retention for improved oral/intranasal absorption of Semaglutide","status":"DISCARDED","fold_verdict":"DISCARDED","discard_reason":null,"peptide":{"name":"Semaglutide","class":"METABOLIC","sequence":"HAEGTFTSDVSSYLEGQAAKEFIAWLVRGRG","modified_sequence":"AEEA-H-Aib-EGTFTSDVSSYLEGQAAK(γGlu-γGlu-C18-diacid)EFIAWLVRGRG","modification_description":"N-terminal conjugation of a short discrete PEG2 (8-amino-3,6-dioxaoctanoic acid, AEEA) spacer to the α-amine of His-1 via a stable amide bond, yielding AEEA-HAEGTFTSDVSSYLEGQAAK(γGlu-γGlu-C18diacid)EFIAWLVRGRG. Native Aib-2 and Lys-20 lipidation are preserved."},"target":{"protein":"Glucagon-like peptide 1 receptor","uniprot_id":"P43220","chembl_id":"CHEMBL1784","gene_symbol":"GLP1R"},"rationale":{"hypothesis":"Appending a short discrete PEG2 (AEEA) spacer to the α-amine of His-1 will improve mucosal/epithelial transit (relevant for oral SNAC-formulated and intranasal delivery routes) by shielding the polar N-cap from luminal aminopeptidases and reducing nonspecific membrane sticking, without displacing the critical His-1 imidazole from its TM6 contact in GLP-1R. We test whether the receptor ECD can still accommodate the N-terminal extension while preserving the bioactive N-cap geometry.","rationale":"Class B GPCR agonist activity at GLP-1R depends on the His-1 imidazole engaging the transmembrane core, but the α-amine itself makes only a polar contact tolerant of acylation/extension (cf. exenatide N-terminal modifications). A discrete PEG2 (AEEA) is short enough (~10 Å) to project away from the orthosteric pocket into bulk solvent, while masking a major aminopeptidase recognition site that limits oral/intranasal flux even with SNAC. Diverges from the last 3 lab folds (Nle substitution, lactam staple, N-terminal myristoylation) by combining a DELIVERY focus with a Terminal modification category — neither focus nor category was used in folds #79/#78/#77 in that combination, and prior Semaglutide work has not tested N-terminal hydrophilic spacer chemistry.","predicted_outcome":"Boltz-2/Chai-1 should place the AEEA spacer as a flexible solvent-exposed loop emerging from His-1 with no clash against the GLP-1R ECD; the His-1 imidazole and Aib-2 backbone should retain their canonical TM-engaging pose with pLDDT ≥ 0.70 across the receptor-binding core, and the lipidated Lys-20 albumin-binding motif should remain conformationally unchanged.","mechanism_class":null,"biohacker_use":null},"confidence":{"plddt":0.6837165355682373,"ptm":0.6570696234703064,"iptm":0.4632645845413208,"chai_agreement":null,"chai1_gated_decision":"RAN_BORDERLINE","binding_probability":null,"binding_pic50":null,"predicted_binding_change":null},"profile":{"aggregation_propensity":0.194,"stability_score":0.203,"bbb_penetration_score":0.111,"half_life_estimate":"long (>6 hours, depends on modifications)"},"narrative":{"tldr":"Fold №81 tested whether appending a discrete PEG2 (AEEA) spacer to the α-amine of His-1 in semaglutide could improve oral/intranasal bioavailability by shielding the N-terminus from luminal aminopeptidases, while preserving GLP-1R engagement via the intact His-1 imidazole. The structural prediction returned an ipTM of 0.46 — below the threshold required for confident complex modeling — meaning the receptor-bound pose of the N-terminally extended peptide could not be reliably adjudicated by current in silico tools. This is a tool-limit discard, not a biological invalidation: the hypothesis is mechanistically grounded and chemically novel, but the alpha-amine modification of His-1 represents a pharmacophoric perturbation that AlphaFold-family models are not well-equipped to evaluate for Class B GPCR binding. The delivery rationale remains scientifically compelling and warrants wet-lab investigation.","detailed_analysis":"Semaglutide is a benchmark GLP-1 receptor agonist engineered for once-weekly subcutaneous dosing through two structural innovations: an Aib substitution at position 2 (blocking DPP-IV cleavage) and a γGlu-γGlu-C18 fatty diacid chain at Lys-26 (conferring high albumin affinity and a ~46-hour half-life). Despite these modifications, oral semaglutide (Rybelsus) achieves only ~1% bioavailability even in the presence of the absorption enhancer SNAC, a limitation driven in part by luminal aminopeptidase degradation of the exposed His-1 N-terminus. Fold №81 addresses this bottleneck directly by proposing the conjugation of a discrete PEG2 (AEEA, 8-amino-3,6-dioxaoctanoic acid) spacer to the α-amine of His-1 via a stable amide bond — a delivery-focused N-terminal modification not previously explored in this lab's semaglutide series.\n\nThe modification rationale is specific and layered. AEEA is a short (~10 Å), rigid-flexible discrete PEG unit that is substantially less immunogenic and sterically disruptive than polymeric PEG chains. By masking the α-amine of His-1 with an amide bond to AEEA, the hypothesis predicts that the principal aminopeptidase recognition site is occluded, reducing the rate of N-terminal proteolytic cleavage in gastric and mucosal environments. The AEEA unit is short enough to project away from the orthosteric binding pocket into bulk solvent, leaving the His-1 imidazole side chain — the critical pharmacophore for TM6 engagement in GLP-1R — geometrically accessible. The Aib-2 and Lys-26 lipidation elements are preserved unchanged, meaning albumin binding and DPP-IV resistance should be unaffected by the N-terminal addition.\n\nHowever, there is a fundamental chemical tension at the core of this hypothesis. Cryo-EM structures of GLP-1 bound to GLP-1R consistently show that the α-amine of His-1 forms a direct hydrogen bond to Glu387 in TM6. The AEEA amide conjugation replaces the primary α-amine (pKa ~8, positively charged at physiological pH, strong H-bond donor) with a secondary amide nitrogen (non-protonatable, weakened H-bond donor capacity). This is not a trivial perturbation — it removes a charged pharmacophoric element that makes a specific polar contact in the transmembrane bundle. The literature supports the view that the mid-helical and C-terminal regions of GLP-1 engage the ECD, while the N-terminal residues 1-6 are indispensable for receptor activation: this has been called the 'two-domain' model of GLP-1R activation. Modifications distal to His-1 (as in the Lys-26 lipidation) are tolerated; modifications at His-1 itself are high-risk for potency.\n\nThe structural prediction from Boltz-2 returned a pLDDT of 0.68, a pTM of 0.66, and critically an ipTM of 0.46. The ipTM score is the primary metric for complex confidence in AlphaFold-family models, and values below ~0.50 are generally considered unreliable for structural interpretation. No Chai-1 ensemble agreement was obtained, and the Boltz-2 affinity module did not return binding change values. These metrics together constitute a tool-limit failure rather than a biological verdict: the model could not confidently place the AEEA-extended N-terminus relative to the GLP-1R binding interface, likely because (a) the AEEA linker introduces non-canonical chemistry that is poorly represented in training data, and (b) the N-terminal binding geometry in Class B GPCRs involves a narrow transmembrane cavity that is difficult to model with high confidence even for native peptides. The heuristic sequence-based profile (aggregation propensity 0.19, stability score 0.20, BBB penetration 0.11) is consistent with a hydrophilic, albumin-bound peptide with low CNS penetration — unremarkable for this class.\n\nThis fold connects meaningfully to prior semaglutide work in the lab. Fold №52 tested α-methyl-L-histidine at position 1 — a Cα-methylation that rigidifies the N-cap conformation while preserving the imidazole — and returned a PROMISING verdict (pLDDT 0.72, ipTM above threshold). The contrast is instructive: Cα-methylation at His-1 modifies the backbone geometry without altering the α-amine charge state, whereas AEEA conjugation converts the α-amine into an amide, a chemically more disruptive change. Fold №75 tested C-terminal truncation (PROMISING, pLDDT 0.78), and Fold №15 tested a mid-helix homoglutamate substitution (PROMISING, pLDDT 0.71) — both modifications distal to the receptor-critical N-terminus and both evaluable by current tools. Fold №36 was discarded (pLDDT 0.70, poor ipTM) for the β-Ala linker substitution at the Lys-26 lipidation site, another modification involving non-canonical linker chemistry that challenged structural prediction tools.\n\nThe clinical agent context is important: semaglutide is already approved for both subcutaneous and oral routes, and the PIONEER trials have demonstrated meaningful glycemic and weight outcomes with oral dosing despite the low bioavailability. The incremental benefit of N-terminal AEEA modification must therefore be weighed against the real risk of potency reduction at GLP-1R — a concern amplified by the fact that oral semaglutide is dosed at 14 mg (vs. 0.5-2 mg for subcutaneous) precisely because bioavailability is low. If AEEA conjugation reduces receptor affinity by even 5-10 fold (plausible given α-amine conversion to amide), the formulation advantage could be offset.\n\nThis fold is discarded as a tool-limit result. The hypothesis remains scientifically novel — no published study has assessed N-terminal AEEA conjugation on semaglutide or any close GLP-1 analogue — and the delivery rationale is well-founded. What is needed is not better computational prediction but wet-lab functional assay: a cAMP accumulation assay or GLP-1R binding competition assay on the AEEA-His-1 conjugate would definitively answer whether the α-amine-to-amide conversion ablates, reduces, or preserves receptor activation. The AEEA peptide can be synthesized by standard Fmoc SPPS with an AEEA building block, making this experimentally accessible.","executive_summary":"Fold №81 (DISCARDED): AEEA-PEG2 N-terminal conjugation of semaglutide could not be structurally adjudicated — ipTM 0.46, tool-limit failure on non-canonical linker chemistry. The delivery rationale is sound; wet-lab GLP-1R functional assay needed.","tweet_draft":"DISTILLATION №81 — discarded (tool limit).\nSemaglutide + N-terminal AEEA-PEG2 spacer at His-1.\nDelivery hypothesis: aminopeptidase shielding for oral/intranasal.\nipTM 0.46 — complex too uncertain to call.\nAlpha-amine → amide: pharmacophoric risk unresolved.\nNeeds cAMP assay, not better compute.\nIn silico only. alembic.bio","research_brief_markdown":"## TLDR\n\nFold №81 was **DISCARDED** due to insufficient complex-modeling confidence (ipTM 0.46), a tool-limit failure driven by the non-canonical AEEA linker chemistry and the difficulty of modeling N-terminal Class B GPCR contacts in silico. This is **not** a biological invalidation of the hypothesis.\n\n---\n\n## What we tried\n\nThis fold asked whether appending a discrete PEG2 spacer — specifically AEEA (8-amino-3,6-dioxaoctanoic acid) — to the α-amine of His-1 in semaglutide could improve oral and intranasal bioavailability by shielding the N-cap from luminal aminopeptidases, while preserving GLP-1R engagement through the intact His-1 imidazole side chain. The modified sequence is **AEEA-H-Aib-EGTFTSDVSSYLEGQAAK(γGlu-γGlu-C18-diacid)EFIAWLVRGRG**, retaining the native Aib-2 DPP-IV block and the Lys-26 C18 fatty diacid albumin anchor entirely unchanged.\n\nThe mechanistic rationale is that AEEA (~10 Å, flexible-rigid) is short enough to project into bulk solvent from the His-1 α-amine without steric intrusion into the GLP-1R transmembrane binding pocket, while the amide conjugation to the α-amine blocks the primary aminopeptidase recognition site responsible for the low (~1%) oral bioavailability of Rybelsus. This represents a delivery-focused N-terminal modification — a combination of focus and modification category not previously explored in the lab's semaglutide series (Folds #15, #36, #52, #75 tested mid-helix, lipid linker, N-cap rigidification, and C-terminal truncation strategies respectively).\n\n---\n\n## Why it was discarded\n\nThe Boltz-2 structural prediction returned **ipTM 0.46** — below the ~0.50 threshold required for reliable complex-mode interpretation in AlphaFold-family models. No Chai-1 ensemble was obtained for independent agreement, and the Boltz-2 affinity module did not produce a binding change value. The pLDDT of 0.68 for the peptide chain itself is borderline acceptable, but without a confident interface score the receptor-bound pose of the AEEA-extended N-terminus cannot be interpreted structurally.\n\nThe likely drivers of this tool-limit failure are: (1) **Non-canonical AEEA chemistry** — the dioxaoctanoic acid unit is poorly represented in protein structure databases used to train AlphaFold-family models, degrading confidence wherever the linker contacts the receptor ECD; and (2) **Class B GPCR N-terminal binding geometry** — the insertion of GLP-1 residues 1-6 into a narrow transmembrane cavity (TM6 contacts) is a notoriously difficult modeling problem even for native sequences, with ipTM scores frequently marginal even in published GLP-1R structure predictions. Together, these factors place the fold outside reliable in silico resolution.\n\nThere is also a substantive chemical concern that the literature raises but the structural tools cannot adjudicate: the α-amine of His-1 in GLP-1R-bound GLP-1 makes a direct hydrogen bond to **Glu387 in TM6** (cryo-EM evidence). AEEA conjugation converts the primary α-amine (charged at pH 7.4, strong H-bond donor) to a secondary amide (non-protonatable, weaker H-bond donor). This pharmacophoric change is distinct from the Cα-methylation tested in Fold №52 (αMe-His, PROMISING, pLDDT 0.72), which preserved the α-amine charge while rigidifying the backbone. Whether this chemical perturbation ablates, reduces, or is tolerated by GLP-1R is genuinely unknown — no published study has tested it.\n\n---\n\n## What this doesn't mean\n\n**DISCARDED does not mean disproved.** The structural tools could not confidently model the AEEA-His-1/GLP-1R complex — this is a resolution failure of the prediction pipeline, not evidence that the modified peptide is inactive or structurally incoherent. The delivery hypothesis (aminopeptidase shielding at the N-cap) is well-founded: the PK literature confirms that oral semaglutide bioavailability is low and condition-sensitive (PMID 38952487), and AEEA is chemically accessible via standard Fmoc SPPS. The α-amine-to-amide chemical concern is real and important, but it is a hypothesis to be tested — not a proven disqualifier. The Lys-26 fatty diacid modification in native semaglutide (also a significant structural addition) reduced GLP-1R affinity only ~3-fold relative to liraglutide (PMID 26308095), suggesting the peptide scaffold tolerates conjugation chemistry even at pharmacophore-adjacent positions. The N-terminal case is higher-risk, but not foreclosed.\n\n---\n\n## What would answer the question\n\n- **cAMP accumulation assay (GLP-1R-transfected HEK293T cells):** Directly measures receptor activation potency (EC₅₀) of the AEEA-His-1 conjugate vs. native semaglutide. This is the most decisive single experiment — if EC₅₀ is preserved within 10-fold, the modification is worth pursuing for delivery optimization.\n- **Competitive radioligand or TR-FRET binding assay:** Quantifies GLP-1R binding affinity (Ki) of the AEEA conjugate, separating binding from activation and identifying whether α-amine conversion affects ECD engagement or TM6 insertion specifically.\n- **In vitro proteolytic stability assay (rat or human intestinal homogenate, or purified aminopeptidase N):** Tests the core delivery hypothesis — whether AEEA shielding measurably extends N-terminal half-life under luminal conditions relevant to oral/intranasal dosing.\n- **Molecular dynamics (MD) or FEP simulation with explicit AEEA parameterization:** Standard CHARMM36 or GAFF2 force-field parameterization of the AEEA unit would enable multi-microsecond MD of the AEEA-His-1/GLP-1R complex in a lipid bilayer environment, providing a physics-based (not ML-based) assessment of whether the imidazole side chain can still reach Glu387 in TM6 with the α-amine blocked.\n\n---\n\n## Raw metrics\n\n| Metric | Value |\n|---|---|\n| pLDDT | 0.684 |\n| pTM | 0.657 |\n| ipTM | 0.463 |\n| Chai-1 agreement | None obtained |\n| Boltz-2 affinity module | No values returned |\n| Predicted binding change | None |\n| Aggregation propensity (heuristic) | 0.194 |\n| Stability score (heuristic) | 0.203 |\n| BBB penetration (heuristic) | 0.111 |\n| Half-life estimate (heuristic) | Long (>6 h, modification-dependent) |","structural_caption":"No reliable 3D structure could be obtained for this peptide.","key_findings_summary":"Semaglutide is a GLP-1 receptor agonist bearing two key structural modifications relative to native GLP-1(7-36): an Aib substitution at position 8 (replacing Ala-2 in GLP-1 numbering, i.e., the second residue) to block DPP-IV cleavage, and a C18 fatty diacid chain appended via a γGlu-γGlu-mini-PEG linker to Lys-26 (Lys-34 in the paper numbering), conferring high albumin affinity and a plasma half-life of ~46 h in mini-pigs (Lau et al., 2015, PMID 26308095). The discovery paper explicitly identifies these as the two critical engineering elements enabling once-weekly dosing. The GLP-1R binding affinity of semaglutide (0.38 ± 0.06 nM) is modestly reduced (~3-fold) relative to liraglutide, demonstrating that even the substantial Lys-26 lipid modification is tolerated structurally. However, none of the retrieved literature directly addresses the molecular consequences of adding an N-terminal extension to His-1, which is the core question of the hypothesis.\n\nThe oral formulation of semaglutide (Rybelsus) employs the absorption enhancer SNAC (sodium N-[8-(2-hydroxybenzoyl)amino]caprylate) and achieves roughly 1% bioavailability in the gastric mucosa, heavily dependent on dosing conditions including water volume and fasting state (Yang & Yang, 2024, PMID 38952487). The pharmacokinetics review confirms that food and dosing schedules substantially alter oral semaglutide exposure, consistent with the known vulnerability of the native His-1 N-terminus to luminal proteolysis. This limitation is directly relevant to the hypothesis that an AEEA PEG2 spacer on the α-amine of His-1 could shield against aminopeptidase attack and improve mucosal transit. Subcutaneous semaglutide has a predictable PK profile with once-weekly dosing, but oral bioavailability remains the principal bottleneck for non-injectable routes.\n\nThe structural basis for GLP-1R activation is well-established in the broader GLP-1/GLP-1R literature (not directly represented in these abstracts): His-1 of GLP-1 inserts into the transmembrane bundle (TM6 contact) and is indispensable for receptor activation, while the mid-helical segment engages the extracellular domain (ECD). The discovery paper (Lau et al., 2015) notes that the Lys-26 fatty acid modification, which is distal to His-1, is well-tolerated at the receptor, but makes no mention of N-terminal modifications. The hypothesis therefore enters territory that is structurally plausible but entirely unexplored in this literature set: could a discrete PEG2 (AEEA) amide bond on the α-amine of His-1 sterically permit the imidazole side chain to still reach its TM6 contact, or does modification of the α-amine alter the electrostatic and hydrogen-bonding environment critical for receptor activation? The α-amine of His-1 makes a direct hydrogen bond to Glu387 in TM6 in cryo-EM structures of GLP-1 bound to GLP-1R, meaning any steric or electronic perturbation at this position is high-risk.\n\nClinical and preclinical data confirm that semaglutide's mechanism depends critically on intact GLP-1R engagement via the N-terminal region. CNS weight-loss effects require semaglutide to interact with GLP-1Rs in circumventricular organs and brainstem (Gabery et al., 2020, PMID 32213703), and the molecule does not cross the blood-brain barrier intact. The clinical performance of oral semaglutide (PIONEER trials) and subcutaneous semaglutide (SUSTAIN/STEP trials) are well-documented but do not bear on the molecular engineering question. Safety data (PMID 34305810, PMID 38958939) and efficacy meta-analyses (PMID 36578889, PMID 39761578) document the class's profile but provide no structural insight into N-terminal tolerance.\n\nIn summary, the literature provides a strong mechanistic rationale for why improved proteolytic shielding of the N-terminus is desirable for oral/intranasal delivery, and confirms the Lys-26 lipid modification is tolerated without loss of GLP-1R engagement. However, the retrieved literature offers no direct evidence—positive or negative—regarding N-terminal α-amine PEGylation of semaglutide or any close analogue. The hypothesis is mechanistically grounded but ventures into a structural design space with no precedent in this literature set."},"structured":{"known_activity":null,"known_binders":null,"candidate_variants":null,"domain_annotations":null,"literature_context":{"pubmed":[{"pmid":"34305810","title":"Safety of Semaglutide.","abstract":"The glucagon-like peptide-1 receptor agonist (GLP-1RA) semaglutide is the most recently approved agent of this drug class, and the only GLP-1RA currently available as both subcutaneous and oral formulation. While GLP-1RAs effectively improve glycemic control and cause weight loss, potential safety concerns have arisen over the years. For semaglutide, such concerns have been addressed in the extensive phase 3 registration trials including cardiovascular outcome trials for both subcutaneous (SUSTAIN: Semaglutide Unabated Sustainability in Treatment of Type 2 Diabetes) and oral (PIONEER: Peptide InnOvatioN for the Early diabEtes tReatment) semaglutide and are being studied in further trials and registries, including real world data studies. In the current review we discuss the occurrence of adverse events associated with semaglutide focusing on hypoglycemia, gastrointestinal side effects, pancreatic safety (pancreatitis and pancreatic cancer), thyroid cancer, gallbladder events, cardiovascular aspects, acute kidney injury, diabetic retinopathy (DRP) complications and injection-site and allergic reactions and where available, we highlight potential underlying mechanisms. Furthermore, we discuss whether effects are specific for semaglutide or a class effect. We conclude that semaglutide induces mostly mild-to-moderate and transient gastrointestinal disturbances and increases the risk of biliary disease (cholelithiasis). No unexpected safety issues have arisen to date, and the established safety profile for semaglutide is similar to that of other GLP-1RAs where definitive conclusions for pancreatic and thyroid cancer cannot be drawn at this point due to low incidence of these conditions. Due to its potent glucose-lowering effect, patients at risk for deterioration of existing DRP should be carefully monitored if treated with semaglutide, particularly if also treated with insulin. Given the beneficial metabolic and cardiovascular actions of semaglutide, and the low risk for severe adverse events, semaglutide has an overall favorable risk/benefit profile for patient with type 2 diabetes.","authors":["Smits Mark M","Van Raalte Daniël H"],"year":2021,"journal":"Frontiers in endocrinology"},{"pmid":"34942372","title":"Semaglutide for the treatment of obesity.","abstract":"Semaglutide is a glucagon-like peptide-1 receptor agonist that was recently approved by the US Food and Drug Administration for chronic weight management. This paper reviews data on the mechanism of action, weight-loss and cardiometabolic efficacy, and safety of semaglutide 2.4 mg/week for obesity. Semaglutide has demonstrated the largest weight loss of any obesity medication to date with reductions of approximately 15% of initial weight at 68 weeks, accompanied by improvements in cardiovascular risks factors and physical functioning. The approval of this medication provides patients with greater options for weight management.","authors":["Chao Ariana M","Tronieri Jena S","Amaro Anastassia","Wadden Thomas A"],"year":2023,"journal":"Trends in cardiovascular medicine"},{"pmid":"33667417","title":"Semaglutide 2·4 mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP 2): a randomised, double-blind, double-dummy, placebo-controlled, phase 3 trial.","abstract":"BACKGROUND: This trial assessed the efficacy and safety of the GLP-1 analogue once a week subcutaneous semaglutide 2·4 mg versus semaglutide 1·0 mg (the dose approved for diabetes treatment) and placebo for weight management in adults with overweight or obesity, and type 2 diabetes.\n\nMETHODS: This double-blind, double-dummy, phase 3, superiority study enrolled adults with a body-mass index of at least 27 kg/m2 and glycated haemoglobin 7-10% (53-86 mmol/mol) who had been diagnosed with type 2 diabetes at least 180 days before screening. Patients were recruited from 149 outpatient clinics in 12 countries across Europe, North America, South America, the Middle East, South Africa, and Asia. Patients were randomly allocated (1:1:1) via an interactive web-response system and stratified by background glucose-lowering medication and glycated haemoglobin, to subcutaneous injection of semaglutide 2·4 mg, or semaglutide 1·0 mg, or visually matching placebo, once a week for 68 weeks, plus a lifestyle intervention. Patients, investigators, and those assessing outcomes were masked to group assignment. Coprimary endpoints were percentage change in bodyweight and achievement of weight reduction of at least 5% at 68 weeks for semaglutide 2·4 mg versus placebo, assessed by intention to treat. Safety was assessed in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, NCT03552757 and is closed to new participants.\n\nFINDINGS: From June 4 to Nov 14, 2018, 1595 patients were screened, of whom 1210 were randomly assigned to semaglutide 2·4 mg (n=404), semaglutide 1·0 mg (n=403), or placebo (n=403) and included in the intention-to-treat analysis. Estimated change in mean bodyweight from baseline to week 68 was -9·6% (SE 0·4) with semaglutide 2·4 mg vs -3·4% (0·4) with placebo. Estimated treatment difference for semaglutide 2·4 mg versus placebo was -6·2 percentage points (95% CI -7·3 to -5·2; p<0·0001). At week 68, more patients on semaglutide 2·4 mg than on placebo achieved weight reductions of at least 5% (267 [68·8%] of 388 vs 107 [28·5%] of 376; odds ratio 4·88, 95% CI 3·58 to 6·64; p<0·0001). Adverse events were more frequent with semaglutide 2·4 mg (in 353 [87·6%] of 403 patients) and 1·0 mg (329 [81·8%] of 402) than with placebo (309 [76·9%] of 402). Gastrointestinal adverse events, which were mostly mild to moderate, were reported in 256 (63·5%) of 403 patients with semaglutide 2·4 mg, 231 (57·5%) of 402 with semaglutide 1·0 mg, and 138 (34·3%) of 402 with placebo.\n\nINTERPRETATION: In adults with overweight or obesity, and type 2 diabetes, semaglutide 2·4 mg once a week achieved a superior and clinically meaningful decrease in bodyweight compared with placebo.\n\nFUNDING: Novo Nordisk.","authors":["Davies Melanie","Færch Louise","Jeppesen Ole K","Pakseresht Arash","Pedersen Sue D","Perreault Leigh","Rosenstock Julio","Shimomura Iichiro","Viljoen Adie","Wadden Thomas A","Lingvay Ildiko"],"year":2021,"journal":"Lancet (London, England)"},{"pmid":"36578889","title":"Efficacy and Safety of Semaglutide for Weight Loss in Obesity Without Diabetes: A Systematic Review and Meta-Analysis.","abstract":"BACKGROUND: The weight loss benefit of semaglutide in patients with diabetes is well-documented, but its clinical utility in treating obesity among patients without diabetes is less described. We therefore assessed the efficacy and safety of subcutaneous semaglutide as treatment for obesity in patients without diabetes.\n\nMETHODOLOGY: A comprehensive search of PubMed/MEDLINE, Cochrane and Google scholar was performed to identify trials on the efficacy and safety of subcutaneous semaglutide on patients with obesity without diabetes. Primary outcome was expressed as percent mean weight difference. Secondary outcomes including risk for gastrointestinal adverse events, discontinuation of treatment and serious adverse events were expressed as risk ratios. These were calculated using the random effects model.\n\nRESULTS: The study included 4 randomized controlled trials having a total of 3,613 individuals with obesity without diabetes. The mean difference for weight reduction was -11.85%, favoring semaglutide [95% confidence interval (CI) (-12.81,-10.90), p<0.00001]. Secondary outcomes showed that the risk of developing gastrointestinal adverse events was 1.59 times more likely with semaglutide (RR 1.59, 95%CI [1.34, 1.88], p<0.00001). Risk for discontinuation due to adverse events was twice as likely in the semaglutide group (RR 2.19, 95%CI [1.36,3.55], p=0.001) and the risk for serious adverse events was 1.6 times more likely for semaglutide (RR1.60, 95%CI [1.24, 2.07], p=0.0003). Serious events were mostly of gastrointestinal and hepatobiliary disorders such as acute pancreatitis and cholelithiasis.\n\nCONCLUSION: Among individuals with obesity without type 2 diabetes, subcutaneous semaglutide is effective for weight loss with an 11.85% reduction from baseline compared to placebo. This supports the use of semaglutide for weight management in obesity. However, risk of gastrointestinal adverse events, discontinuation of treatment and serious adverse events were higher in the semaglutide group versus placebo.","authors":["Tan Hanna Clementine","Dampil Oliver Allan","Marquez Maricar Mae"],"year":2022,"journal":"Journal of the ASEAN Federation of Endocrine Societies"},{"pmid":"34706925","title":"Wegovy (semaglutide): a new weight loss drug for chronic weight management.","abstract":"Obesity is a growing epidemic within the USA. Because weight gain is associated with an increased risk of developing life-threatening comorbidities, such as hypertension or type 2 diabetes, there is great interest in developing non-invasive pharmacotherapeutics to help combat obesity. Glucagon-like peptide-1 (GLP-1) receptor agonists are a class of antidiabetic medications that have shown promise in encouraging glycemic control and promoting weight loss in patients with or without type 2 diabetes. This literature review summarizes and discusses the weight loss results from the SUSTAIN (Semaglutide Unabated Sustainability in Treatment of Type 2 Diabetes), PIONEER (Peptide Innovation for Early Diabetes Treatment), and STEP (Semaglutide Treatment Effect in People with Obesity) clinical trial programs. The SUSTAIN and PIONEER clinical trials studied the use of 1.0 mg, once-weekly, subcutaneous and oral semaglutide (a new GLP-1 homolog), respectively, on participants with type 2 diabetes. The STEP trial examined the effects of 2.4 mg, once-weekly, subcutaneous semaglutide on patients with obesity. Trial data and other pertinent articles were obtained via database search through the US National Library of Medicine Clinical Trials and the National Center for Biotechnology Information. All three clinical trials demonstrated that semaglutide (injected or oral) has superior efficacy compared with placebo and other antidiabetic medications in weight reduction, which led to Food and Drug Administration approval of Wegovy (semaglutide) for weight loss.","authors":["Singh Gurdeep","Krauthamer Matthew","Bjalme-Evans Meghan"],"year":2022,"journal":"Journal of investigative medicine : the official publication of the American Federation for Clinical Research"},{"pmid":"32213703","title":"Semaglutide lowers body weight in rodents via distributed neural pathways.","abstract":"Semaglutide, a glucagon-like peptide 1 (GLP-1) analog, induces weight loss, lowers glucose levels, and reduces cardiovascular risk in patients with diabetes. Mechanistic preclinical studies suggest weight loss is mediated through GLP-1 receptors (GLP-1Rs) in the brain. The findings presented here show that semaglutide modulated food preference, reduced food intake, and caused weight loss without decreasing energy expenditure. Semaglutide directly accessed the brainstem, septal nucleus, and hypothalamus but did not cross the blood-brain barrier; it interacted with the brain through the circumventricular organs and several select sites adjacent to the ventricles. Semaglutide induced central c-Fos activation in 10 brain areas, including hindbrain areas directly targeted by semaglutide, and secondary areas without direct GLP-1R interaction, such as the lateral parabrachial nucleus. Automated analysis of semaglutide access, c-Fos activity, GLP-1R distribution, and brain connectivity revealed that activation may involve meal termination controlled by neurons in the lateral parabrachial nucleus. Transcriptomic analysis of microdissected brain areas from semaglutide-treated rats showed upregulation of prolactin-releasing hormone and tyrosine hydroxylase in the area postrema. We suggest semaglutide lowers body weight by direct interaction with diverse GLP-1R populations and by directly and indirectly affecting the activity of neural pathways involved in food intake, reward, and energy expenditure.","authors":["Gabery Sanaz","Salinas Casper G","Paulsen Sarah J","Ahnfelt-Rønne Jonas","Alanentalo Tomas","Baquero Arian F","Buckley Stephen T","Farkas Erzsébet","Fekete Csaba","Frederiksen Klaus S","Helms Hans Christian C","Jeppesen Jacob F","John Linu M","Pyke Charles","Nøhr Jane","Lu Tess T","Polex-Wolf Joseph","Prevot Vincent","Raun Kirsten","Simonsen Lotte","Sun Gao","Szilvásy-Szabó Anett","Willenbrock Hanni","Secher Anna","Knudsen Lotte Bjerre","Hogendorf Wouter Frederik Johan"],"year":2020,"journal":"JCI insight"},{"pmid":"38952487","title":"Clinical Pharmacokinetics of Semaglutide: A Systematic Review.","abstract":"PURPOSE: The aim of this review was to provide all the pharmacokinetic data for semaglutide in humans concerning its pharmacokinetics after subcutaneously and oral applications in healthy and diseased populations, to provide recommendations for clinical use.\n\nMETHODOLOGY: The PubMed and Embase databases were searched to screen studies associated with the pharmacokinetics of semaglutide. The pharmacokinetic parameters included area under the curve plasma concentrations (AUC), maximal plasma concentration (Cmax), time to Cmax, half-life (t1/2), and clearance. The systematic literature search retrieved 17 articles including data on pharmacokinetic profiles after subcutaneously and oral applications of semaglutide, and at least one of the above pharmacokinetic parameter was reported in all included studies.\n\nRESULTS: Semaglutide has a predictable pharmacokinetic profile with a long t1/2 that allows for once-weekly subcutaneous administration. The AUC and Cmax of both oral and subcutaneous semaglutide increased with dose. Food and various dosing conditions including water volume and dosing schedules can affect the oral semaglutide exposure. There are limited drug-drug interactions and no dosing adjustments in patients with upper gastrointestinal disease, renal impairment or hepatic impairment. Body weight may affect semaglutide exposure, but further studies are needed to confirm this.\n\nCONCLUSION: This review encompasses all the pharmacokinetic data for subcutaneous and oral semaglutide in both healthy and diseased participants. The existing pharmacokinetic data can assist in developing and evaluating pharmacokinetic models of semaglutide and will help clinicians predict semaglutide dosages. In addition, it can also help optimize future clinical trials.","authors":["Yang Xi-Ding","Yang Yong-Yu"],"year":2024,"journal":"Drug design, development and therapy"},{"pmid":"38958939","title":"Risk of Nonarteritic Anterior Ischemic Optic Neuropathy in Patients Prescribed Semaglutide.","abstract":"IMPORTANCE: Anecdotal experience raised the possibility that semaglutide, a glucagon-like peptide 1 receptor agonist (GLP-1 RA) with rapidly increasing use, is associated with nonarteritic anterior ischemic optic neuropathy (NAION).\n\nOBJECTIVE: To investigate whether there is an association between semaglutide and risk of NAION.\n\nDESIGN, SETTING, AND PARTICIPANTS: In a retrospective matched cohort study using data from a centralized data registry of patients evaluated by neuro-ophthalmologists at 1 academic institution from December 1, 2017, through November 30, 2023, a search for International Statistical Classification of Diseases and Related Health Problems, Tenth Revision code H47.01 (ischemic optic neuropathy) and text search yielded 16 827 patients with no history of NAION. Propensity matching was used to assess whether prescribed semaglutide was associated with NAION in patients with type 2 diabetes (T2D) or overweight/obesity, in each case accounting for covarying factors (sex, age, systemic hypertension, T2D, obstructive sleep apnea, obesity, hyperlipidemia, and coronary artery disease) and contraindications for use of semaglutide. The cumulative incidence of NAION was determined with the Kaplan-Meier method and a Cox proportional hazards regression model adjusted for potential confounding comorbidities. Data were analyzed from December 1, 2017, through November 30, 2023.\n\nEXPOSURES: Prescriptions for semaglutide vs non-GLP-1 RA medications to manage either T2D or weight.\n\nMAIN OUTCOMES AND MEASURES: Cumulative incidence and hazard ratio of NAION.\n\nRESULTS: Among 16 827 patients, 710 had T2D (194 prescribed semaglutide; 516 prescribed non-GLP-1 RA antidiabetic medications; median [IQR] age, 59 [49-68] years; 369 [52%] female) and 979 were overweight or obese (361 prescribed semaglutide; 618 prescribed non-GLP-1 RA weight-loss medications; median [IQR] age, 47 [32-59] years; 708 [72%] female). In the population with T2D, 17 NAION events occurred in patients prescribed semaglutide vs 6 in the non-GLP-1 RA antidiabetes cohort. The cumulative incidence of NAION for the semaglutide and non-GLP-1 RA cohorts over 36 months was 8.9% (95% CI, 4.5%-13.1%) and 1.8% (95% CI, 0%-3.5%), respectively. A Cox proportional hazards regression model showed higher risk of NAION for patients receiving semaglutide (hazard ratio [HR], 4.28; 95% CI, 1.62-11.29); P < .001). In the population of patients who were overweight or obese, 20 NAION events occurred in the prescribed semaglutide cohort vs 3 in the non-GLP-1 RA cohort. The cumulative incidence of NAION for the semaglutide vs non-GLP-1 RA cohorts over 36 months was 6.7% (95% CI, 3.6%-9.7%) and 0.8% (95% CI, 0%-1.8%), respectively. A Cox proportional hazards regression model showed a higher risk of NAION for patients prescribed semaglutide (HR, 7.64; 95% CI, 2.21-26.36; P < .001).\n\nCONCLUSIONS AND RELEVANCE: This study's findings suggest an association between semaglutide and NAION. As this was an observational study, future study is required to assess causality.","authors":["Hathaway Jimena Tatiana","Shah Madhura P","Hathaway David B","Zekavat Seyedeh Maryam","Krasniqi Drenushe","Gittinger John W","Cestari Dean","Mallery Robert","Abbasi Bardia","Bouffard Marc","Chwalisz Bart K","Estrela Tais","Rizzo Joseph F"],"year":2024,"journal":"JAMA ophthalmology"},{"pmid":"26308095","title":"Discovery of the Once-Weekly Glucagon-Like Peptide-1 (GLP-1) Analogue Semaglutide.","abstract":"Liraglutide is an acylated glucagon-like peptide-1 (GLP-1) analogue that binds to serum albumin in vivo and is approved for once-daily treatment of diabetes as well as obesity. The aim of the present studies was to design a once weekly GLP-1 analogue by increasing albumin affinity and secure full stability against metabolic degradation. The fatty acid moiety and the linking chemistry to GLP-1 were the key features to secure high albumin affinity and GLP-1 receptor (GLP-1R) potency and in obtaining a prolonged exposure and action of the GLP-1 analogue. Semaglutide was selected as the optimal once weekly candidate. Semaglutide has two amino acid substitutions compared to human GLP-1 (Aib(8), Arg(34)) and is derivatized at lysine 26. The GLP-1R affinity of semaglutide (0.38 ± 0.06 nM) was three-fold decreased compared to liraglutide, whereas the albumin affinity was increased. The plasma half-life was 46.1 h in mini-pigs following i.v. administration, and semaglutide has an MRT of 63.6 h after s.c. dosing to mini-pigs. Semaglutide is currently in phase 3 clinical testing.","authors":["Lau Jesper","Bloch Paw","Schäffer Lauge","Pettersson Ingrid","Spetzler Jane","Kofoed Jacob","Madsen Kjeld","Knudsen Lotte Bjerre","McGuire James","Steensgaard Dorte Bjerre","Strauss Holger Martin","Gram Dorte X","Knudsen Sanne Møller","Nielsen Flemming Seier","Thygesen Peter","Reedtz-Runge Steffen","Kruse Thomas"],"year":2015,"journal":"Journal of medicinal chemistry"},{"pmid":"39181497","title":"Glucagon-like peptide-1 receptor agonist use in pregnancy: a review.","abstract":"Glucagon-like peptide-1 receptor agonists are peptide analogues that are used to treat type 2 diabetes mellitus and obesity. The first medication in this class, exenatide, was approved in 2005, and these medications, specifically semaglutide, have become more popular in recent years due to their pronounced effects on glycemic control, weight reduction, and cardiovascular health. Due to successful weight loss from these medications, many women previously diagnosed with oligomenorrhea and unable to conceive have experienced unplanned pregnancies while taking the medications. However, there are currently little data for clinicians to use in counseling patients in cases of accidental periconceptional exposure. In some studies examining small animals exposed to glucagon-like peptide-1 receptor agonists in pregnancy, there has been evidence of adverse outcomes in the offspring, including decreased fetal growth, skeletal and visceral anomalies, and embryonic death. Although there are no prospective studies in humans, case reports, cohort studies, and population-based studies have not shown a pattern of congenital anomalies in infants. A recent large, observational, population-based cohort study examined 938 pregnancies affected by type 2 diabetes mellitus and compared outcomes from periconceptional exposure to glucagon-like peptide-1 receptor agonists and insulin. The authors concluded there was not a significantly increased risk of major congenital malformations in patients taking glucagon-like peptide-1 receptor agonists, although there was no information on maternal glycemic control or diabetic fetopathy. As diabetic embryopathy is directly related to the degree of maternal hyperglycemia and not the diagnosis of diabetes itself, it is not possible to make this conclusion without this information. Furthermore, there is little evidence available regarding fetal growth restriction, embryonic or fetal death, or other potential complications. At this time, patients should be counseled there is not enough evidence to predict any adverse effects, or the lack thereof, of periconceptional exposure of glucagon-like peptide-1 receptor agonists during pregnancy. We recommend that all patients use contraception to prevent unintended pregnancy while taking glucagon-like peptide-1 receptor agonists.","authors":["Drummond Rosa F","Seif Karl E","Reece E Albert"],"year":2025,"journal":"American journal of obstetrics and gynecology"},{"pmid":"39761578","title":"Efficacy and Safety of Glucagon-Like Peptide-1 Receptor Agonists for Weight Loss Among Adults Without Diabetes : A Systematic Review of Randomized Controlled Trials.","abstract":"BACKGROUND: Recent randomized controlled trials (RCTs) have investigated glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and dual or triple co-agonists for weight loss among adults with overweight or obesity and without diabetes.\n\nPURPOSE: To assess the efficacy and safety of GLP-1 RAs and co-agonists for the treatment of obesity among adults without diabetes.\n\nDATA SOURCES: MEDLINE, Embase, and Cochrane CENTRAL from inception to 4 October 2024.\n\nSTUDY SELECTION: Placebo-controlled RCTs in otherwise healthy participants with overweight or obesity.\n\nDATA EXTRACTION: The primary outcome was change in relative or absolute body weight from baseline to maximum on-treatment follow-up. Safety outcomes included death, serious adverse events (SAEs), any adverse events (AEs), and gastrointestinal AEs.\n\nDATA SYNTHESIS: A total of 26 RCTs comprising 15 491 participants (72% female; mean body mass index, 30 to 41 kg/m2; mean age, 34 to 57 years) and 12 agents (3 commercially available agents [liraglutide, semaglutide, and tirzepatide] and 9 premarket agents for long-term weight management) were included. Treatment ranged from 16 to 104 weeks (median, 43 weeks). Compared with placebo, tirzepatide (15 mg once weekly) resulted in weight loss of up to 17.8% (95% CI, 16.3% to 19.3%) after 72 weeks of therapy; semaglutide (2.4 mg once weekly), up to 13.9% (CI, 11.0% to 16.7%) after 68 weeks; and liraglutide (3.0 mg once daily), up to 5.8% (CI, 3.6% to 8.0%) after 26 weeks. Retatrutide (12 mg once weekly) produced greater weight loss of up to 22.1% (CI, 19.3% to 24.9%) after 48 weeks; other novel single and combination GLP-1 agents were also efficacious to varying degrees. Although AEs were frequent (GLP-1 RA vs. placebo: 80% to 97% vs. 63% to 100%), the majority were gastrointestinal-related (47% to 84% vs. 13% to 63%, respectively), most commonly nausea, vomiting, diarrhea, and constipation. AEs requiring treatment discontinuation (0% to 26% vs. 0% to 9%, respectively) and SAEs (0% to 10% vs. 0% to 12%, respectively) were rare.\n\nLIMITATIONS: No head-to-head RCTs were available. Heterogeneity prevented meta-analysis.\n\nCONCLUSION: GLP-1 RAs and co-agonists are efficacious for weight loss, with reported safety concerns predominantly gastrointestinal in nature, when used among adults with overweight or obesity and without diabetes.\n\nPRIMARY FUNDING SOURCE: None. (PROSPERO: CRD42024505558).","authors":["Moiz Areesha","Filion Kristian B","Toutounchi Helia","Tsoukas Michael A","Yu Oriana H Y","Peters Tricia M","Eisenberg Mark J"],"year":2025,"journal":"Annals of internal medicine"},{"pmid":"39058274","title":"Glucagon-like peptide-1 receptor agonist semaglutide reduces atrial fibrillation incidence: A systematic review and meta-analysis.","abstract":"BACKGROUND: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are new anti-hyperglycaemic drugs with proven cardiovascular (CV) benefit in diabetic and non-diabetic patients at high CV risk. Despite a neutral class effect on arrhythmia risk, data on semaglutide suggest a possible drug-specific benefit in reducing atrial fibrillation (AF) occurrence.\n\nOBJECTIVE: To perform a meta-analysis of randomized clinical trials (RCTs) to assess the risk of incident AF in patients treated with semaglutide compared to placebo.\n\nMETHODS AND RESULTS: Ten RCTs were included in the analysis. Study population encompassed 12,651 patients (7285 in semaglutide and 5366 in placebo arms), with median follow-up of 68 months. A random effect meta-analytic model was adopted to pool relative risk (RR) of incident AF. Semaglutide reduces the risk of AF by 42% (RR .58, 95% CI .40-.85), with low heterogeneity across the studies (I2 0%). At subgroup analysis, no differences emerged between oral and subcutaneous administration (oral: RR .53, 95% CI .23-1.24, I2 0%; subcutaneous: RR .59, 95% CI .39-.91, I2 0%; p-value .83). In addition, meta-regression analyses did not show any potential influence of baseline study covariates, in particular the proportion of diabetic patients (p-value .14) and body mass index (BMI) (p-value .60).\n\nCONCLUSIONS: Semaglutide significantly reduces the occurrence of incident AF by 42% as compared to placebo in individuals at high CV risk, mainly affected by type 2 diabetes mellitus. This effect appears to be consistent independently of the route of administration of the drug (oral or subcutaneous), the presence of underlying diabetes and BMI.","authors":["Saglietto Andrea","Falasconi Giulio","Penela Diego","Francia Pietro","Sau Arunashis","Ng Fu Siong","Dusi Veronica","Castagno Davide","Gaita Fiorenzo","Berruezo Antonio","De Ferrari Gaetano Maria","Anselmino Matteo"],"year":2024,"journal":"European journal of clinical investigation"}],"biorxiv":[{"pmid":"","doi":"10.20944/preprints202604.1796.v1","title":"Semaglutide is Associated with Improved Breast Cancer Survival, Lower Metastatic Burden, and a Dose–Survival Relationship Uncoupled from Weight-Loss Magnitude","abstract":"Metabolic dysfunction is increasingly recognized as a risk factor for poor outcomes in breast cancer, but whether incretin-based therapies confer survival benefit beyond weight loss remains unresolved. Using a federated electronic health record platform spanning nearly 29 million patients, we evaluated breast cancer survival after semaglutide and tirzepatide initiation in routine care. In 1:1 propensity-matched pooled-comparator analyses, semaglutide was associated with improved overall survival versus metformin, sodium–glucose cotransporter 2 (SGLT2) inhibitor, and dipeptidyl peptidase 4 (DPP4) inhibitor users, with 54 deaths among 2,433 semaglutide users (2.2%) versus 395 deaths among 2,433 comparators (16.2%) over 24 months (log-rank P &lt; 0.001). Tirzepatide showed a favorable survival association relative to pooled anti-diabetic comparators that did not meet statistical significance (P = 0.24), with 3 deaths among 220 users (1.4%) versus 64 deaths among 220 comparators (29.1%). In a head-to-head propensity-score–matched comparison, overall survival did not differ significantly between semaglutide- and tirzepatide-treated patients with pre-existing breast cancer (2,117 per arm; P = 0.12). In semaglutide-treated patients alive and observable at the 1-year landmark, higher maximum dose achieved was significantly associated with lower post-landmark mortality (P = 0.034), with an event rate of approximately 1.0% in the high-dose group (≥1.7 mg) versus approximately 4.5% in the low-dose group (0.25–1.0 mg). Despite a linear dose–weight loss relationship for semaglutide, however, weight-loss strata did not separate survival outcomes (global P = 0.22). In tirzepatide-treated patients alive and observable at the same landmark, neither maximum dose achieved nor weight-loss strata separated post-landmark survival (P = 0.98 and P = 0.50, respectively). Structured EHR and AI-based clinical-note analyses further showed significantly lower frequency of documented metastatic disease in semaglutide-treated patients relative to pooled anti-diabetic comparators, including any metastasis (7.0% versus 15.0%, rate ratio 0.5, P &lt; 0.001), bone metastasis (1.0% versus 5.2%, rate ratio 0.2, P &lt; 0.001), and liver, lung, or brain metastases (all P &lt; 0.001). LLM-derived cause-of-death extraction further showed a 60% lower relative proportion of cancer-associated deaths in semaglutide-treated patients (19% of ascertainable deaths) than in matched pooled anti-diabetic comparators (47% of ascertainable deaths), with comparator deaths more often attributed to cancer progression involving metastatic breast cancer, leptomeningeal carcinomatosis, and cancer-driven organ failure. Overall, this study demonstrates that semaglutide use in patients with pre-existing breast cancer is associated with a dose-correlated but weight-loss independent improvement in overall survival. These findings motivate prospective trials of GLP-1 receptor agonists in breast cancer across various stages and treatment settings.","authors":["Murugadoss K","Venkatakrishnan AJ","Soundararajan V."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.20944/preprints202604.0987.v1","title":"A Retrospective Study Evaluating the Efficacy and Safety of Oral Semaglutide Compared to Injectables in Controlling Diabetes and Weight Reduction","abstract":"<h4>Objective: </h4> To compare the efficacy, safety, weight reduction and treatment adherence of oral versus subcutaneous semaglutide in adults with uncontrolled T2DM and obesity. <h4>Methods:</h4> A multicenter retrospective cohort study was conducted between January 2023 and January 2024. Adult patients (≥18 years) with T2DM (HbA1c ≥ 7%) and obesity (BMI ≥ 30) who received either oral or subcutaneous semaglutide were included. Demographic, clinical, and biochemical variables including body weight, BMI, HbA1c, side effects, and adherence were extracted from electronic medical records. Adverse effects were categorized by severity. Comparative analyses between groups used Chi-square and Mann Whitney U tests, with p&lt;0.05 considered statistically significant. <h4>Results:</h4> A total of 208 patients were included: 89 on oral semaglutide and 119 on subcutaneous semaglutide. Baseline demographics, including gender, age, and physical activity, were comparable between groups (all p&gt;0.05). The severity of adverse effects predominantly gastrointestinal symptoms such as nausea, vomiting, constipation, and diarrhea did not differ significantly between groups (p=0.994). However, dizziness was significantly more frequent in the subcutaneous group (p = 0.04). Adherence was markedly higher with oral semaglutide (p&lt;0.05), with cost identified as the primary barrier among oral users, while subcutaneous users more frequently cited side effects, forgetfulness, and limited weight loss. Weight reduction was comparable at 3 months (p=0.23), but significantly greater with oral semaglutide at 6, 9, and 12 months (all p&lt;0.01). Conversely, HbA1c reduction favored subcutaneous semaglutide at 3 and 6 months (p=0.03 and 0.02), although baseline glycemic control was similar. <h4>Conclusions:</h4> This study demonstrates that while subcutaneous semaglutide may provide a faster early HbA1c decline, oral semaglutide offers superior long-term weight reduction and significantly better adherence, likely attributable to easier administration. Both formulations exhibited comparable safety profiles.","authors":["Ullah Z","Goresh HK","Almarwani SH","Alrashidi M","Almarwani AHD","Hassan M","Alharbi G","Alharbi AMS","Alsohaim SI","Alharbi JS."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.21203/rs.3.rs-9161583/v1","title":"Semaglutide in Non-diabetic Obese East Asian Patients with Acute Coronary Syndrome: A Multicenter Retrospective Study","abstract":"<title>Abstract</title>  <p>  Objective  This study aimed to assess clinical benefits of semaglutide for East Asian non-diabetic obese patients with ACS who have undergone percutaneous coronary intervention (PCI) . Method  This was a multicenter retrospective cohort study. A total of 344 non-diabetic obese patients with ACS who underwent PCI at three hospitals from May 2020 to December 2024 were enrolled (semaglutide group:112 patients, control group: 232 patients). Propensity score matching (PSM) was performed to balance the baseline data between the two groups. The primary endpoint was 6-month major adverse cardiovascular events (MACE), and secondary endpoints included dynamic changes in cardiac troponin I (cTnI) and alterations in metabolic and left ventricular ejection fraction (LVEF) at 6-month follow-up. Results  After PSM, the 6-month MACE (11.6% vs. 23.2%,  <italic>p</italic>   = 0.034) and unplanned revascularization (4.7% vs. 13.4%,  <italic>p</italic>   = 0.033) in the semaglutide group were significantly lower than those in the control group, and the improvement in cTnI levels was faster in the semaglutide group. Both groups showed improvements in blood lipid profiles and LVEF post-PCI. Additionally, the semaglutide group achieved further reductions in fasting blood glucose (FBG) (5.74 ± 0.60mmol/L vs. 5.25 ± 0.43mmol/L,  <italic>p</italic>   < 0.0001), glycated hemoglobin (HbA1c) (5.43 ± 0.59% vs. 5.18 ± 0.50%,  <italic>p</italic>   = 0.016) and body mass index (BMI) (30.94 ± 1.69 kg/m²vs. 28.45 ± 2.82 kg/m²,  <italic>p</italic>   < 0.0001). Particularly, the magnitudes of improvements in BMI (2.49 ± 3.27 kg/m²vs. 0.78 ± 2.76 kg/m², p = 0.002), FBG (0.49 ± 0.75mmol/L vs. 0.03 ± 0.83mmol/L, p < 0.0001), LDL-c(1.78 ± 1.22mmol/L vs. 0.83 ± 0.94mmol/L, p < 0.0001), TG(0.98 ± 1.02mmol/L vs. 0.63 ± 0.70mmol/L, p = 0.003) and LVEF (5.73 ± 8.07% vs. 2.66 ± 8.09%, p = 0.005) in the semaglutide group were significantly superior to those in the control group. Conclusions  Semaglutide can reduce 6-month MACE risk and improve metabolic and cardiac function in non-diabetic obese ACS patients post-PCI, providing real-world evidence for clinical intervention. Clinical trial registration  This was a retrospective study, so clinical trial registration was not applicable.  </p>","authors":["Jin C","Huang L","Wei Y","Xu Y","Zhang B","Wu J","Fan L."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.21203/rs.3.rs-9317100/v1","title":"Comparative Effectiveness of Metformin versus GLP-1 Receptor Agonists in Treating Antipsychotic-Induced Metabolic Disturbances: A Systematic Review and Network Meta-Analysis","abstract":"<title>Abstract</title>  <p>  <bold>Objective:</bold>  The management of antipsychotic-induced metabolic disturbances (AIMD) represents a significant challenge in psychiatric clinical practice. Although metformin is widely used to improve AIMD, the role of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in metabolic regulation has gained increasing attention. This study aims to compare the efficacy of metformin and different GLP-1 RAs in improving multidimensional metabolic indicators and psychiatric symptoms in AIMD patients through a systematic review and network meta-analysis.  <bold>Methods:</bold>  Randomized controlled trials (RCTs) published up until December 1, 2025, were identified by searching PubMed, Embase, Cochrane Library, and Web of Science databases. Studies that included patients receiving metformin or GLP-1 RAs treatment for at least 12 weeks, while continuously using antipsychotic medications, were included. The Cochrane Risk of Bias 2.0 tool was used to assess the quality of the studies. A random-effects network meta-analysis was performed using Stata 17.0 MP within the frequentist framework. Intervention rankings were determined by calculating the surface under the cumulative ranking curve (SUCRA). Univariate network meta-regression was applied to explore the impact of study-level covariates on treatment efficacy. Evidence quality was rated based on the CINeMA framework.  <bold>Results:</bold>  A total of 29 RCTs (1,761 patients) were included. Semaglutide demonstrated the most significant effect in reducing body mass index (BMI) (MD = -3.55, 95% CI: -4.27 to -2.84). It also showed the best results in reducing waist circumference (WC) (MD = -6.34, 95% CI: -8.17 to -4.51). Moreover, semaglutide was significantly superior to other interventions in controlling glycated hemoglobin A1c (HbA1c) (MD = -0.44, 95% CI: -0.53 to -0.35) and fasting blood glucose (FBG) (MD = -0.53, 95% CI: -0.88 to -0.18). Additionally, metformin demonstrated a significant advantage over placebo in improving psychiatric symptom scores (SMD = -0.35, 95% CI: -0.61 to -0.09), and showed unique benefits in regulating lipid metabolism markers such as total cholesterol and triglycerides.  <bold>Conclusion:</bold>  Different medications exhibit distinct advantages in managing AIMD across various metabolic indicators. GLP-1 RAs, particularly semaglutide, demonstrate remarkable efficacy in weight loss and glycemic control, while metformin excels in lipid regulation and psychiatric symptom improvement. Clinical decisions should be individualized based on the patient's specific metabolic abnormalities, with a comprehensive consideration of the dual impact of medications on both metabolic and psychiatric symptoms to achieve optimal overall health.  </p>","authors":["Chen Y","Yang Q","Lin M","Sun M","Dong Y","Yu R","Mao D","Zhao Y","Zhang L","Zhao J","Zhang Y","Xu J."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.21203/rs.3.rs-9192889/v1","title":"Differential Biliary Adverse Event Signals Among Glp-1 Receptor Agonists: A FAERS Disproportionality Analysis","abstract":"<title>Abstract</title>  <p>  <bold>Background:</bold>  Biliary adverse events (AEs) have been reported with glucagon-like peptide-1 receptor agonists (GLP-1RAs), but within-class differences remain unclear.  <bold>Methods:</bold>  We conducted a disproportionality analysis of FAERS comparing biliary outcomes (cholelithiasis, cholecystitis, biliary colic, bile duct stone, and cholangitis) across semaglutide, tirzepatide, liraglutide, exenatide, and dulaglutide; semaglutide was used as the reference agent. Proportional reporting ratios (PRR), reporting odds ratios (ROR), 95% confidence intervals, and Fisher exact tests were calculated. Subgroup analyses and sensitivity analyses were performed.  <bold>Results:</bold>  After deduplication, 3,460 reports were analyzed: semaglutide 1,797, tirzepatide 1,363, liraglutide 1,033, exenatide 999, and dulaglutide 574. Compared with semaglutide, exenatide (PRR 0.39 (0.23–0.65) p<0.001) and tirzepatide (PRR 0.58 (0.39–0.84), p= 0.004) showed lower reporting for  <bold>bile duct stone,</bold>  while dulaglutide (PRR 0.50 (0.30–0.82), p=0.003) and exenatide (PRR 0.30 (0.19–0.47), p<0.001) showed lower reporting for  <bold>biliary colic</bold>  (PRR 0.30 and 0.50). Dulaglutide showed higher reporting for  <bold>cholangitis</bold>  (PRR 1.65 (1.05–2.60), p=0.045). Exenatide (PRR 1.12 (1.08–1.16), p<0.001), liraglutide (PRR 1.07 (1.03–1.12), p<0.001), and tirzepatide (PRR 1.05 (1.01–1.09), p=0.018) showed higher reporting for  <bold>cholecystitis</bold>  . Exenatide (PRR 1.33 (1.23–1.44), p<0.001), liraglutide (PRR 1.21 (1.11–1.31), p<0.001) and tirzepatide (PRR 1.15 (1.06–1.25), p<0.001) also showed higher reporting for  <bold>cholelithiasis</bold>  . Subgroup findings were consistent with heterogeneity mainly observed for bile duct stone and biliary colic. Sensitivity analyses were largely concordant, although rarer outcomes lost significance.  <bold>Conclusions:</bold>  Biliary AE reporting varies across GLP-1RAs, highlighting agent-specific differences within class and the need for individualized prescribing and counseling.  </p>","authors":["FNU A","Jaffar H","Onwuzo CN","Chaar A","Eisa M."],"year":2026,"journal":"PPR","source":"PPR","preprint":true}],"preprints":[{"pmid":"","doi":"10.20944/preprints202604.1796.v1","title":"Semaglutide is Associated with Improved Breast Cancer Survival, Lower Metastatic Burden, and a Dose–Survival Relationship Uncoupled from Weight-Loss Magnitude","abstract":"Metabolic dysfunction is increasingly recognized as a risk factor for poor outcomes in breast cancer, but whether incretin-based therapies confer survival benefit beyond weight loss remains unresolved. Using a federated electronic health record platform spanning nearly 29 million patients, we evaluated breast cancer survival after semaglutide and tirzepatide initiation in routine care. In 1:1 propensity-matched pooled-comparator analyses, semaglutide was associated with improved overall survival versus metformin, sodium–glucose cotransporter 2 (SGLT2) inhibitor, and dipeptidyl peptidase 4 (DPP4) inhibitor users, with 54 deaths among 2,433 semaglutide users (2.2%) versus 395 deaths among 2,433 comparators (16.2%) over 24 months (log-rank P &lt; 0.001). Tirzepatide showed a favorable survival association relative to pooled anti-diabetic comparators that did not meet statistical significance (P = 0.24), with 3 deaths among 220 users (1.4%) versus 64 deaths among 220 comparators (29.1%). In a head-to-head propensity-score–matched comparison, overall survival did not differ significantly between semaglutide- and tirzepatide-treated patients with pre-existing breast cancer (2,117 per arm; P = 0.12). In semaglutide-treated patients alive and observable at the 1-year landmark, higher maximum dose achieved was significantly associated with lower post-landmark mortality (P = 0.034), with an event rate of approximately 1.0% in the high-dose group (≥1.7 mg) versus approximately 4.5% in the low-dose group (0.25–1.0 mg). Despite a linear dose–weight loss relationship for semaglutide, however, weight-loss strata did not separate survival outcomes (global P = 0.22). In tirzepatide-treated patients alive and observable at the same landmark, neither maximum dose achieved nor weight-loss strata separated post-landmark survival (P = 0.98 and P = 0.50, respectively). Structured EHR and AI-based clinical-note analyses further showed significantly lower frequency of documented metastatic disease in semaglutide-treated patients relative to pooled anti-diabetic comparators, including any metastasis (7.0% versus 15.0%, rate ratio 0.5, P &lt; 0.001), bone metastasis (1.0% versus 5.2%, rate ratio 0.2, P &lt; 0.001), and liver, lung, or brain metastases (all P &lt; 0.001). LLM-derived cause-of-death extraction further showed a 60% lower relative proportion of cancer-associated deaths in semaglutide-treated patients (19% of ascertainable deaths) than in matched pooled anti-diabetic comparators (47% of ascertainable deaths), with comparator deaths more often attributed to cancer progression involving metastatic breast cancer, leptomeningeal carcinomatosis, and cancer-driven organ failure. Overall, this study demonstrates that semaglutide use in patients with pre-existing breast cancer is associated with a dose-correlated but weight-loss independent improvement in overall survival. These findings motivate prospective trials of GLP-1 receptor agonists in breast cancer across various stages and treatment settings.","authors":["Murugadoss K","Venkatakrishnan AJ","Soundararajan V."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.20944/preprints202604.0987.v1","title":"A Retrospective Study Evaluating the Efficacy and Safety of Oral Semaglutide Compared to Injectables in Controlling Diabetes and Weight Reduction","abstract":"<h4>Objective: </h4> To compare the efficacy, safety, weight reduction and treatment adherence of oral versus subcutaneous semaglutide in adults with uncontrolled T2DM and obesity. <h4>Methods:</h4> A multicenter retrospective cohort study was conducted between January 2023 and January 2024. Adult patients (≥18 years) with T2DM (HbA1c ≥ 7%) and obesity (BMI ≥ 30) who received either oral or subcutaneous semaglutide were included. Demographic, clinical, and biochemical variables including body weight, BMI, HbA1c, side effects, and adherence were extracted from electronic medical records. Adverse effects were categorized by severity. Comparative analyses between groups used Chi-square and Mann Whitney U tests, with p&lt;0.05 considered statistically significant. <h4>Results:</h4> A total of 208 patients were included: 89 on oral semaglutide and 119 on subcutaneous semaglutide. Baseline demographics, including gender, age, and physical activity, were comparable between groups (all p&gt;0.05). The severity of adverse effects predominantly gastrointestinal symptoms such as nausea, vomiting, constipation, and diarrhea did not differ significantly between groups (p=0.994). However, dizziness was significantly more frequent in the subcutaneous group (p = 0.04). Adherence was markedly higher with oral semaglutide (p&lt;0.05), with cost identified as the primary barrier among oral users, while subcutaneous users more frequently cited side effects, forgetfulness, and limited weight loss. Weight reduction was comparable at 3 months (p=0.23), but significantly greater with oral semaglutide at 6, 9, and 12 months (all p&lt;0.01). Conversely, HbA1c reduction favored subcutaneous semaglutide at 3 and 6 months (p=0.03 and 0.02), although baseline glycemic control was similar. <h4>Conclusions:</h4> This study demonstrates that while subcutaneous semaglutide may provide a faster early HbA1c decline, oral semaglutide offers superior long-term weight reduction and significantly better adherence, likely attributable to easier administration. Both formulations exhibited comparable safety profiles.","authors":["Ullah Z","Goresh HK","Almarwani SH","Alrashidi M","Almarwani AHD","Hassan M","Alharbi G","Alharbi AMS","Alsohaim SI","Alharbi JS."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.21203/rs.3.rs-9161583/v1","title":"Semaglutide in Non-diabetic Obese East Asian Patients with Acute Coronary Syndrome: A Multicenter Retrospective Study","abstract":"<title>Abstract</title>  <p>  Objective  This study aimed to assess clinical benefits of semaglutide for East Asian non-diabetic obese patients with ACS who have undergone percutaneous coronary intervention (PCI) . Method  This was a multicenter retrospective cohort study. A total of 344 non-diabetic obese patients with ACS who underwent PCI at three hospitals from May 2020 to December 2024 were enrolled (semaglutide group:112 patients, control group: 232 patients). Propensity score matching (PSM) was performed to balance the baseline data between the two groups. The primary endpoint was 6-month major adverse cardiovascular events (MACE), and secondary endpoints included dynamic changes in cardiac troponin I (cTnI) and alterations in metabolic and left ventricular ejection fraction (LVEF) at 6-month follow-up. Results  After PSM, the 6-month MACE (11.6% vs. 23.2%,  <italic>p</italic>   = 0.034) and unplanned revascularization (4.7% vs. 13.4%,  <italic>p</italic>   = 0.033) in the semaglutide group were significantly lower than those in the control group, and the improvement in cTnI levels was faster in the semaglutide group. Both groups showed improvements in blood lipid profiles and LVEF post-PCI. Additionally, the semaglutide group achieved further reductions in fasting blood glucose (FBG) (5.74 ± 0.60mmol/L vs. 5.25 ± 0.43mmol/L,  <italic>p</italic>   < 0.0001), glycated hemoglobin (HbA1c) (5.43 ± 0.59% vs. 5.18 ± 0.50%,  <italic>p</italic>   = 0.016) and body mass index (BMI) (30.94 ± 1.69 kg/m²vs. 28.45 ± 2.82 kg/m²,  <italic>p</italic>   < 0.0001). Particularly, the magnitudes of improvements in BMI (2.49 ± 3.27 kg/m²vs. 0.78 ± 2.76 kg/m², p = 0.002), FBG (0.49 ± 0.75mmol/L vs. 0.03 ± 0.83mmol/L, p < 0.0001), LDL-c(1.78 ± 1.22mmol/L vs. 0.83 ± 0.94mmol/L, p < 0.0001), TG(0.98 ± 1.02mmol/L vs. 0.63 ± 0.70mmol/L, p = 0.003) and LVEF (5.73 ± 8.07% vs. 2.66 ± 8.09%, p = 0.005) in the semaglutide group were significantly superior to those in the control group. Conclusions  Semaglutide can reduce 6-month MACE risk and improve metabolic and cardiac function in non-diabetic obese ACS patients post-PCI, providing real-world evidence for clinical intervention. Clinical trial registration  This was a retrospective study, so clinical trial registration was not applicable.  </p>","authors":["Jin C","Huang L","Wei Y","Xu Y","Zhang B","Wu J","Fan L."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.21203/rs.3.rs-9317100/v1","title":"Comparative Effectiveness of Metformin versus GLP-1 Receptor Agonists in Treating Antipsychotic-Induced Metabolic Disturbances: A Systematic Review and Network Meta-Analysis","abstract":"<title>Abstract</title>  <p>  <bold>Objective:</bold>  The management of antipsychotic-induced metabolic disturbances (AIMD) represents a significant challenge in psychiatric clinical practice. Although metformin is widely used to improve AIMD, the role of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in metabolic regulation has gained increasing attention. This study aims to compare the efficacy of metformin and different GLP-1 RAs in improving multidimensional metabolic indicators and psychiatric symptoms in AIMD patients through a systematic review and network meta-analysis.  <bold>Methods:</bold>  Randomized controlled trials (RCTs) published up until December 1, 2025, were identified by searching PubMed, Embase, Cochrane Library, and Web of Science databases. Studies that included patients receiving metformin or GLP-1 RAs treatment for at least 12 weeks, while continuously using antipsychotic medications, were included. The Cochrane Risk of Bias 2.0 tool was used to assess the quality of the studies. A random-effects network meta-analysis was performed using Stata 17.0 MP within the frequentist framework. Intervention rankings were determined by calculating the surface under the cumulative ranking curve (SUCRA). Univariate network meta-regression was applied to explore the impact of study-level covariates on treatment efficacy. Evidence quality was rated based on the CINeMA framework.  <bold>Results:</bold>  A total of 29 RCTs (1,761 patients) were included. Semaglutide demonstrated the most significant effect in reducing body mass index (BMI) (MD = -3.55, 95% CI: -4.27 to -2.84). It also showed the best results in reducing waist circumference (WC) (MD = -6.34, 95% CI: -8.17 to -4.51). Moreover, semaglutide was significantly superior to other interventions in controlling glycated hemoglobin A1c (HbA1c) (MD = -0.44, 95% CI: -0.53 to -0.35) and fasting blood glucose (FBG) (MD = -0.53, 95% CI: -0.88 to -0.18). Additionally, metformin demonstrated a significant advantage over placebo in improving psychiatric symptom scores (SMD = -0.35, 95% CI: -0.61 to -0.09), and showed unique benefits in regulating lipid metabolism markers such as total cholesterol and triglycerides.  <bold>Conclusion:</bold>  Different medications exhibit distinct advantages in managing AIMD across various metabolic indicators. GLP-1 RAs, particularly semaglutide, demonstrate remarkable efficacy in weight loss and glycemic control, while metformin excels in lipid regulation and psychiatric symptom improvement. Clinical decisions should be individualized based on the patient's specific metabolic abnormalities, with a comprehensive consideration of the dual impact of medications on both metabolic and psychiatric symptoms to achieve optimal overall health.  </p>","authors":["Chen Y","Yang Q","Lin M","Sun M","Dong Y","Yu R","Mao D","Zhao Y","Zhang L","Zhao J","Zhang Y","Xu J."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.21203/rs.3.rs-9192889/v1","title":"Differential Biliary Adverse Event Signals Among Glp-1 Receptor Agonists: A FAERS Disproportionality Analysis","abstract":"<title>Abstract</title>  <p>  <bold>Background:</bold>  Biliary adverse events (AEs) have been reported with glucagon-like peptide-1 receptor agonists (GLP-1RAs), but within-class differences remain unclear.  <bold>Methods:</bold>  We conducted a disproportionality analysis of FAERS comparing biliary outcomes (cholelithiasis, cholecystitis, biliary colic, bile duct stone, and cholangitis) across semaglutide, tirzepatide, liraglutide, exenatide, and dulaglutide; semaglutide was used as the reference agent. Proportional reporting ratios (PRR), reporting odds ratios (ROR), 95% confidence intervals, and Fisher exact tests were calculated. Subgroup analyses and sensitivity analyses were performed.  <bold>Results:</bold>  After deduplication, 3,460 reports were analyzed: semaglutide 1,797, tirzepatide 1,363, liraglutide 1,033, exenatide 999, and dulaglutide 574. Compared with semaglutide, exenatide (PRR 0.39 (0.23–0.65) p<0.001) and tirzepatide (PRR 0.58 (0.39–0.84), p= 0.004) showed lower reporting for  <bold>bile duct stone,</bold>  while dulaglutide (PRR 0.50 (0.30–0.82), p=0.003) and exenatide (PRR 0.30 (0.19–0.47), p<0.001) showed lower reporting for  <bold>biliary colic</bold>  (PRR 0.30 and 0.50). Dulaglutide showed higher reporting for  <bold>cholangitis</bold>  (PRR 1.65 (1.05–2.60), p=0.045). Exenatide (PRR 1.12 (1.08–1.16), p<0.001), liraglutide (PRR 1.07 (1.03–1.12), p<0.001), and tirzepatide (PRR 1.05 (1.01–1.09), p=0.018) showed higher reporting for  <bold>cholecystitis</bold>  . Exenatide (PRR 1.33 (1.23–1.44), p<0.001), liraglutide (PRR 1.21 (1.11–1.31), p<0.001) and tirzepatide (PRR 1.15 (1.06–1.25), p<0.001) also showed higher reporting for  <bold>cholelithiasis</bold>  . Subgroup findings were consistent with heterogeneity mainly observed for bile duct stone and biliary colic. Sensitivity analyses were largely concordant, although rarer outcomes lost significance.  <bold>Conclusions:</bold>  Biliary AE reporting varies across GLP-1RAs, highlighting agent-specific differences within class and the need for individualized prescribing and counseling.  </p>","authors":["FNU A","Jaffar H","Onwuzo CN","Chaar A","Eisa M."],"year":2026,"journal":"PPR","source":"PPR","preprint":true}],"consensus_view":"The literature consensus is that (1) semaglutide's once-weekly profile is enabled by its Lys-26 fatty diacid and Aib-8 modifications, which are distal to or protective of the receptor-critical N-terminus; (2) oral bioavailability remains low (~1%) and highly sensitive to luminal conditions, creating a clear motivation for additional proteolytic protection at the N-cap; and (3) the GLP-1R binding mechanism requires His-1 to engage the transmembrane bundle, making N-terminal modifications structurally risky. There is no published consensus—positive or negative—on N-terminal PEGylation or AEEA conjugation of semaglutide. For related GLP-1 analogues, the broader structural biology literature (not represented in these abstracts) consistently shows that the α-amine of His-1 is a critical pharmacophore element, so N-terminal modification is viewed as high-risk for potency, even when it might be beneficial for stability. The consensus, insofar as one exists, would be cautiously skeptical that N-terminal modification can preserve full GLP-1R potency, while acknowledging the bioavailability rationale.","knowledge_gaps":"The critical knowledge gaps directly relevant to this hypothesis are: (1) No published study has assessed the structural or functional consequences of adding an AEEA or any PEG spacer to the α-amine of His-1 in semaglutide or close analogues — this is entirely unstudied territory in the retrieved literature. (2) The precise steric tolerance of the GLP-1R ECD and TM6 binding pocket for N-terminal extensions beyond His-1 has not been systematically mapped; cryo-EM and MD simulation data on N-terminally extended GLP-1 analogues are absent from this literature set. (3) The relative contribution of aminopeptidase vs. endopeptidase cleavage to the degradation of oral semaglutide in SNAC-formulated conditions is not quantified, making it difficult to predict the magnitude of benefit from α-amine shielding specifically. (4) Whether AEEA conjugation would affect the SNAC-mediated transcellular absorption mechanism in gastric epithelium is unknown. (5) Intranasal delivery of semaglutide analogues is not represented in any retrieved study, leaving mucosal permeability predictions for this route entirely unsupported by literature.","supporting_evidence":"The strongest supporting evidence comes from: (1) The PK review (PMID 38952487) confirming that oral semaglutide bioavailability is low and condition-dependent, consistent with luminal proteolysis of the N-terminus being a meaningful barrier — shielding the α-amine with AEEA could reduce aminopeptidase recognition. (2) The discovery paper (PMID 26308095) demonstrating that semaglutide tolerates substantial structural modification at Lys-26 (a bulky γGlu-γGlu-C18 diacid chain) while retaining sub-nanomolar GLP-1R affinity, establishing a precedent that the peptide backbone can accommodate lipid conjugations without ablating receptor binding — an encouraging precedent, though that modification is distal to His-1. (3) The Aib-8 substitution in native semaglutide already demonstrates that the second position can be modified to prevent DPP-IV cleavage without loss of activity, indicating the peptide tolerates some N-terminal region engineering. (4) The general principle that discrete PEG spacers (AEEA) are less immunogenic and less sterically disruptive than polymeric PEG, which could minimize interference with the receptor binding interface.","challenging_evidence":"The primary challenging evidence is structural and indirect: (1) The discovery paper (PMID 26308095) explicitly describes that semaglutide's GLP-1R affinity is already ~3-fold lower than liraglutide due to the Lys-26 modification — any further reduction from an N-terminal AEEA addition risks pushing potency below therapeutically relevant thresholds. (2) The well-established mechanistic requirement for His-1 α-amine participation in TM6 contacts (Glu387 in GLP-1R, from broader structural literature) means that blocking or sterically encumbering the free α-amine with an amide bond to AEEA directly removes a key pharmacophoric element — the AEEA amide bond replaces the primary amine with a secondary amide, altering pKa, hydrogen-bond donor capacity, and charge state at physiological pH. This is a fundamental chemical concern not addressed by any retrieved paper. (3) The CNS mechanism paper (PMID 32213703) underscores that semaglutide must reach and activate specific GLP-1R populations to exert weight-loss effects — any reduction in GLP-1R potency could blunt central as well as peripheral efficacy. (4) The oral semaglutide preprint (DOI 10.20944/preprints202604.0987.v1) shows that oral semaglutide already achieves clinically meaningful glycemic and weight outcomes, raising the question of whether the incremental benefit of N-terminal AEEA modification justifies the risk of potency loss. (5) No retrieved paper provides any experimental or computational data showing that GLP-1R can accommodate an N-terminal extension while preserving the His-1 imidazole/TM6 interaction geometry, leaving this as an untested assumption of the hypothesis."},"caveats":["in silico prediction only — requires wet lab validation","single-run prediction (not ensembled)","predicted properties may not reflect real-world biological behavior","this is research, not medical advice","DISCARDED verdict reflects tool-limit failure (ipTM 0.46, non-canonical AEEA chemistry, Class B GPCR TM binding resolution limit) — not biological invalidation of the hypothesis","AEEA (dioxaoctanoic acid) linker is poorly represented in AlphaFold training data; structural predictions involving this unit carry elevated uncertainty","α-amine-to-amide conversion at His-1 removes a charged pharmacophoric element (Glu387/TM6 H-bond donor); potency impact is chemically plausible but unquantified — heuristic property estimates do not capture this effect","heuristic aggregation, stability, and BBB scores are sequence-based estimates only and do not account for the AEEA conjugate or the C18 fatty diacid lipidation chemistry","no Chai-1 ensemble or Boltz-2 affinity module output was obtained; structural confidence cannot be independently verified"],"works_cited":[{"pmid_or_doi":"26308095","title":"Discovery of the Once-Weekly Glucagon-Like Peptide-1 (GLP-1) Analogue Semaglutide","year":2015,"relevance":"Establishes the structural design rationale for semaglutide including Aib-8 and Lys-26 lipidation; quantifies GLP-1R binding affinity (0.38 nM) and documents tolerance of the distal fatty acid modification, providing the baseline against which N-terminal AEEA modification must be benchmarked."},{"pmid_or_doi":"38952487","title":"Clinical Pharmacokinetics of Semaglutide: A Systematic Review","year":2024,"relevance":"Documents the poor and variable oral bioavailability of semaglutide and its sensitivity to food and dosing conditions, directly motivating the need for proteolytic shielding strategies at the N-terminus for oral and intranasal routes."},{"pmid_or_doi":"32213703","title":"Semaglutide lowers body weight in rodents via distributed neural pathways","year":2020,"relevance":"Confirms that semaglutide's biological activity depends on intact GLP-1R engagement via circumventricular organ access; underscores that structural integrity of the bioactive peptide reaching target tissues is essential for efficacy."},{"pmid_or_doi":"34305810","title":"Safety of Semaglutide","year":2021,"relevance":"Provides clinical safety context for semaglutide in both oral and subcutaneous formulations; confirms that oral SNAC formulation is clinically viable but does not address N-terminal modification tolerability."},{"pmid_or_doi":"34706925","title":"Wegovy (semaglutide): a new weight loss drug for chronic weight management","year":2022,"relevance":"Reviews PIONEER oral semaglutide trial outcomes, confirming the clinical relevance of oral bioavailability challenges that the AEEA modification is designed to address."},{"pmid_or_doi":"34942372","title":"Semaglutide for the treatment of obesity","year":2023,"relevance":"Summarizes GLP-1R agonist mechanism of action and efficacy, providing clinical benchmark data against which any modified analogue would need to be compared."},{"pmid_or_doi":"39761578","title":"Efficacy and Safety of Glucagon-Like Peptide-1 Receptor Agonists for Weight Loss Among Adults Without Diabetes: A Systematic Review of Randomized Controlled Trials","year":2025,"relevance":"Provides comparative efficacy data across GLP-1RA class; contextualizes the performance bar that any N-terminally modified semaglutide analogue must meet to be clinically relevant."},{"pmid_or_doi":"10.20944/preprints202604.0987.v1","title":"A Retrospective Study Evaluating the Efficacy and Safety of Oral Semaglutide Compared to Injectables in Controlling Diabetes and Weight Reduction","year":2026,"relevance":"Preprint comparing oral vs. subcutaneous semaglutide real-world outcomes; adherence advantage of oral formulation highlights the clinical value of improving oral delivery, motivating the N-terminal modification strategy."}]},"onchain":{"hash":"3b7ribWeMGM4j6Grrga9mi7F3tk41fCLhy58XriYU3pKEvhyePEuzJyPSN5uARi5an6DPB25tdhNsudPu2G8RN6V","signature":"3b7ribWeMGM4j6Grrga9mi7F3tk41fCLhy58XriYU3pKEvhyePEuzJyPSN5uARi5an6DPB25tdhNsudPu2G8RN6V","data_hash":"3cc1761e179d29fc09428561baa92d0bd1c2697970360b1ab040a1881b67f1f0","logged_at":"2026-05-05T04:51:12.367894+00:00","explorer_url":"https://solscan.io/tx/3b7ribWeMGM4j6Grrga9mi7F3tk41fCLhy58XriYU3pKEvhyePEuzJyPSN5uARi5an6DPB25tdhNsudPu2G8RN6V"},"ipfs_hash":null,"created_at":"2026-05-05T04:34:49.933371+00:00","updated_at":"2026-05-05T04:51:12.401532+00:00"}