Introduction:

Retatrutide (LY3437943) is a triple-agonist peptide (GLP-1, GIP, glucagon) advancing through a broad Phase 3 TRIUMPH program after Phase 2 studies showed large, dose-dependent weight reduction and favorable metabolic signals.¹⁻³ Ongoing trials span weight management, outcomes (CV/renal), musculoskeletal pain in obesity, and comorbidity subpopulations.⁴⁻¹¹

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Key Trials at a Glance (as of August 16, 2025)

Insert Figure 1: Horizontal timeline of major retatrutide trials (Phase 2 → Phase 3 TRIUMPH program), with estimated primary completion dates.
ALT: “Timeline of retatrutide trials from Phase 2 through ongoing Phase 3 studies.”
Caption: “Figure 1. Retatrutide clinical development milestones and expected readouts.”

Program / NCT	Phase	Population / Focus	Status*	Duration / Est. Primary Completion
TRIUMPH-Outcomes (NCT06383390)	3	BMI ≥27 with ASCVD and/or CKD; event-driven CV & kidney outcomes	Recruiting across global sites⁶⁻¹²	~5 years; Est. primary completion Feb 2029⁹
Maintenance of Weight Reduction (NCT06859268)	3	Adults with obesity; weight-loss maintenance after open-label lead-in	Active – Recruiting (last updated Jul 28, 2025)⁴	80-wk lead-in + 36-wk RCT; Est. completion Apr 2028⁴
Chronic Low Back Pain in Obesity (NCT07035093)	3	Adults with obesity/overweight + chronic low back pain	Active – Recruiting (last updated Jul 11, 2025)⁵	~80 weeks; Est. completion Sep 2027⁵
Head-to-Head vs Tirzepatide (NCT06662383; “TRIUMPH-5”)	3	Adults with obesity; retatrutide vs tirzepatide	Active – Not Recruiting; ~800 planned; ~89 weeks⁷⁻⁸,¹¹	Started Nov 2024; primary readout expected after ~89 wks⁷,¹¹
Obesity + OA of Knee (TRIUMPH-4) (NCT05931367)	3	Overweight/obesity with knee osteoarthritis	Active – Not Recruiting; ~77 weeks³,¹³	Started Aug 2023; Est. primary completion Dec 2025¹³
Renal Function in CKD (mixed T2D/no-T2D) (NCT05936151)	2	Overweight/obesity with CKD	Active – Not Recruiting (last updated May 5, 2025)¹⁰,¹⁴	~31 weeks; kidney endpoints (e.g., measured GFR, UACR)¹⁰,¹⁵

*Status reflects site/registry listings most recently updated in July 2025 where available.

Insert Figure 2: World map with pins for active trial geographies (US, Canada, UK, EU, LATAM, etc.), using HP brand colors.
ALT: “Global map of current retatrutide trial sites by study.”
Caption: “Figure 2. Geographic footprint of active Phase 3 retatrutide trials.”

Completed/Published Signals Informing Phase 3

• Phase 2 obesity trial (NEJM 2023): Up to 24% mean weight reduction at 48 weeks; robust lipid and liver fat improvements noted in follow-up reporting.¹,²,¹⁶
  
• Program expansion: Lilly’s TRIUMPH Phase 3 suite spans weight management, outcomes, and comorbid populations.⁶

What to Watch Next

1. First Phase 3 readouts from condition-specific RCTs (e.g., OA knee, back pain) likely before the outcomes trial, given shorter durations.³,⁵,¹³
   
2. Head-to-head efficacy/tolerability vs tirzepatide (NCT06662383) — pivotal for comparative positioning once results mature.⁷⁻⁸,¹¹

CV/renal outcomes (TRIUMPH-Outcomes) — decisive, but on a longer horizon (event-driven; est. primary completion 2029).⁹

FAQs: Retatrutide Trials

Related Articles

• What is Retatrutide
• How Does Retatrutide Work
• Retatrutide Benefits
• Retatrutide Side Effects & Safety
• Semaglutide vs Tirzepatide vs Retatrutide
• What is Semaglutide
• What is Tirzepatide

References

1. Jastreboff AM, et al. N Engl J Med. 2023;389(2):145–158. “Triple–Hormone-Receptor Agonist Retatrutide for Obesity.” https://www.nejm.org/doi/full/10.1056/NEJMoa2301972 New England Journal of Medicine
   
2. Lilly press release (Phase 2 publication). https://investor.lilly.com/news-releases/news-release-details/lillys-phase-2-retatrutide-results-published-new-england-journal Lilly Investor Relations
   
3. Abouelmagd AA, et al. Review of early-phase data. Front Endocrinol/PMC (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC12026077/ PMC