{"id":"exenatide","name":"Exenatide","aliases":["Byetta","Bydureon","exendin-4","AC2993"],"url":"https://lyoresearch.com/compounds/exenatide","class":{"id":"glp-1-agonists","name":"GLP-1 and incretin agonists","url":"https://lyoresearch.com/classes/glp-1-agonists"},"summary":"Exenatide is a synthetic copy of exendin-4, a peptide from Gila-monster saliva, and the drug that opened the GLP-1 class in 2005. It is approved for type 2 diabetes as a twice-daily injection and a weekly one. In the 14,752-person EXSCEL trial it was safe but did not significantly reduce cardiovascular events, unlike the drugs that followed it. A phase 3 trial testing it as a disease-modifying treatment for Parkinson's disease, the use it is most searched for today, found no benefit. It is prescription-only.","overall_grade":"A","overall_grade_meaning":"established in humans","human_trials":"EXSCEL (n=14,752) + DURATION programme + Parkinson's phase 3","regulatory_status":"Approved (Rx)","molecule":{"formula":"C184H282N50O60S","molecular_weight":"4187","cas":"141758-74-9","pubchem_cid":45588096,"note":null},"pharmacokinetics":{"basis":"label","route":"Subcutaneous injection, twice daily before meals","half_life":"About 2.4 hours","licensed_regimen":"5 mcg twice daily within 60 minutes before morning and evening meals; may increase to 10 mcg twice daily after 1 month","product":"Byetta","source":{"title":"Byetta prescribing information (DailyMed)","url":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=53d03c03-ebf7-418d-88a8-533eabd2ee4f"}},"outcomes":[{"outcome":"Blood glucose (HbA1c)","grade":"A","grade_meaning":"established in humans","effect_size":"moderate","adverse":false,"human_studies":"DURATION and AMIGO programmes","evidence":"Approval-grade HbA1c reductions with both formulations; the licensed indication since 2005.","references":[{"citation":"Exenatide (Byetta, Bydureon) product information and the AMIGO / DURATION programmes.","where":"FDA / EMA product information","url":"https://www.ema.europa.eu/en/medicines/human/EPAR/byetta"}]},{"outcome":"Body weight","grade":"A","grade_meaning":"established in humans","effect_size":"small","adverse":false,"human_studies":"Multiple RCTs","evidence":"Modest, consistent weight loss of a few kilograms in diabetes trials. Not approved for weight management.","references":[{"citation":"Exenatide (Byetta, Bydureon) product information and the AMIGO / DURATION programmes.","where":"FDA / EMA product information","url":"https://www.ema.europa.eu/en/medicines/human/EPAR/byetta"}]},{"outcome":"Major cardiovascular events (type 2 diabetes)","grade":"A","grade_meaning":"established in humans","effect_size":"not measurable","adverse":false,"human_studies":"1 large RCT (n=14,752, median 3.2 yr)","evidence":"Non-inferior to placebo for safety, but not superior: the 9% relative reduction missed statistical significance. The class benefit shown by liraglutide, semaglutide and dulaglutide was not demonstrated for exenatide.","references":[{"citation":"Holman RR, Bethel MA, Mentz RJ, et al. Effects of once-weekly exenatide on cardiovascular outcomes in type 2 diabetes.","where":"N Engl J Med, 2017","url":"https://pubmed.ncbi.nlm.nih.gov/28910237/"}],"verbatim":{"text":"Among patients with type 2 diabetes with or without previous cardiovascular disease, the incidence of major adverse cardiovascular events did not differ significantly between patients who received exenatide and those who received placebo.","citation":"Holman RR, Bethel MA, Mentz RJ, et al. Effects of once-weekly exenatide on cardiovascular outcomes in type 2 diabetes.","url":"https://pubmed.ncbi.nlm.nih.gov/28910237/"}},{"outcome":"Parkinson's disease progression","grade":"B","grade_meaning":"probable, not settled","effect_size":"not measurable","adverse":false,"human_studies":"1 phase 3 RCT (n=194, 96 wk) — negative; 1 phase 2 positive","evidence":"After a positive 62-person phase 2 in 2017, the 194-person phase 3 found motor scores worsened equally on exenatide and placebo over 96 weeks. The Lancet's editors have since issued an Expression of Concern on the phase 3 paper; the notice does not change the result, but readers should know it exists.","references":[{"citation":"Vijiaratnam N, Girges C, Auld G, et al. Exenatide once a week versus placebo as a potential disease-modifying treatment for people with Parkinson's disease in the UK: a phase 3, multicentre, double-blind, parallel-group, randomised, placebo-controlled trial.","where":"Lancet, 2025","url":"https://pubmed.ncbi.nlm.nih.gov/39919773/"},{"citation":"Athauda D, Maclagan K, Skene SS, et al. Exenatide once weekly versus placebo in Parkinson's disease: a randomised, double-blind, placebo-controlled trial.","where":"Lancet, 2017","url":"https://pubmed.ncbi.nlm.nih.gov/28781108/"},{"citation":"The Editors of The Lancet. Expression of Concern: Exenatide once a week versus placebo as a potential disease-modifying treatment for people with Parkinson's disease in the UK.","where":"Lancet, 2026","url":"https://pubmed.ncbi.nlm.nih.gov/42330995/"}],"verbatim":{"text":"At 96 weeks, MDS-UPDRS III OFF-medication scores had increased (worsened) by a mean of 5·7 points (SD 11·2) in the exenatide group, and by 4·5 points (SD 11·4) points in the placebo group (adjusted coefficient for the effect of exenatide 0·92 [95% CI -1·56 to 3·39]; p=0·47).","citation":"Vijiaratnam N, Girges C, Auld G, et al. Exenatide once a week versus placebo as a potential disease-modifying treatment for people with Parkinson's disease in the UK: a phase 3, multicentre, double-blind, parallel-group, randomised, placebo-controlled trial.","url":"https://pubmed.ncbi.nlm.nih.gov/39919773/"}},{"outcome":"Adverse effects","grade":"A","grade_meaning":"established in humans","effect_size":"moderate","adverse":true,"human_studies":"EXSCEL and programme","evidence":"Nausea and other gastrointestinal effects, injection-site nodules with the weekly formulation. Pancreatitis, pancreatic cancer and thyroid carcinoma did not differ from placebo in EXSCEL.","references":[{"citation":"Holman RR, Bethel MA, Mentz RJ, et al. Effects of once-weekly exenatide on cardiovascular outcomes in type 2 diabetes.","where":"N Engl J Med, 2017","url":"https://pubmed.ncbi.nlm.nih.gov/28910237/"}]}],"regions":[{"region":"European Union","status":"Approved, prescription-only","note":"Centrally authorised for type 2 diabetes (Byetta 2006; Bydureon 2011)."},{"region":"United States","status":"Approved, prescription-only","note":"FDA-approved 2005 (Byetta) and 2012 (Bydureon) for type 2 diabetes."},{"region":"United Kingdom","status":"Licensed, prescription-only","note":"MHRA-licensed for type 2 diabetes."},{"region":"Australia","status":"Registered, prescription-only","note":"On the ARTG for type 2 diabetes."},{"region":"Canada","status":"Authorised, prescription-only","note":"Health Canada-authorised for type 2 diabetes."},{"region":"Sport (WADA)","status":"Not prohibited","note":"GLP-1 receptor agonists are not on the Prohibited List."}],"faq":[{"q":"Does exenatide help Parkinson's disease?","a":"The phase 3 trial says no: 194 people over 96 weeks, and motor scores worsened equally on drug and placebo. An earlier 62-person phase 2 had been positive, which is why the larger trial was run. The Lancet has issued an Expression of Concern on the phase 3 paper without stating why."},{"q":"Does exenatide protect the heart like semaglutide?","a":"Not on the evidence. EXSCEL found no significant reduction in cardiovascular events; the 9% relative reduction missed significance. Liraglutide, semaglutide and dulaglutide each showed a benefit in their trials."},{"q":"Is exenatide still used?","a":"It remains approved and available, but has been largely superseded by weekly drugs with larger effects on weight and proven cardiovascular benefit."}],"references":[{"cite":"Holman RR, Bethel MA, Mentz RJ, et al. Effects of once-weekly exenatide on cardiovascular outcomes in type 2 diabetes.","where":"N Engl J Med, 2017","url":"https://pubmed.ncbi.nlm.nih.gov/28910237/","note":"EXSCEL; 14,752 patients; HR 0.91, P=0.06 for superiority."},{"cite":"Vijiaratnam N, Girges C, Auld G, et al. Exenatide once a week versus placebo as a potential disease-modifying treatment for people with Parkinson's disease in the UK: a phase 3, multicentre, double-blind, parallel-group, randomised, placebo-controlled trial.","where":"Lancet, 2025","url":"https://pubmed.ncbi.nlm.nih.gov/39919773/","note":"Exenatide-PD3; 194 participants; 96 weeks; no effect. See ref 5."},{"cite":"Exenatide (Byetta, Bydureon) product information and the AMIGO / DURATION programmes.","where":"FDA / EMA product information","url":"https://www.ema.europa.eu/en/medicines/human/EPAR/byetta","note":"Licensed indications and the glucose and weight data."},{"cite":"Athauda D, Maclagan K, Skene SS, et al. Exenatide once weekly versus placebo in Parkinson's disease: a randomised, double-blind, placebo-controlled trial.","where":"Lancet, 2017","url":"https://pubmed.ncbi.nlm.nih.gov/28781108/","note":"Phase 2; 62 participants; positive on the off-medication motor score — the result the phase 3 was designed to confirm."},{"cite":"The Editors of The Lancet. Expression of Concern: Exenatide once a week versus placebo as a potential disease-modifying treatment for people with Parkinson's disease in the UK.","where":"Lancet, 2026","url":"https://pubmed.ncbi.nlm.nih.gov/42330995/","note":"Notice attached to ref 2. No abstract; the reason is not stated in the notice."}],"last_reviewed":"2026-09-10","literature_searched_to":"2026-09-10","changelog":[{"date":"2026-09-10","note":"Initial publication. Grade A on the approval programme and EXSCEL; Parkinson's carries a null phase 3 (grade B, effect none) with the Expression of Concern noted."}],"license":"CC BY 4.0 — cite as “LYO Research” with a link.","methodology":"https://lyoresearch.com/methodology"}