All 3 Phases of TRIUMPH Program: All Explained (2026 Update)

Research use only: Retatrutide is an investigational compound and is not approved by the FDA for human use. Information on this page is for research and educational purposes only and does not constitute medical advice or an endorsement to purchase for personal use.

Results for the Phase 3 TRIUMPH-3 trial, which evaluates the triple hormone receptor agonist retatrutide for adults with obesity and cardiovascular disease, are expected later in 2026.

TRIUMPH is the short form of TRIple agonist Investigation for Understanding Metabolic Pathways and Health. It is research a major series of Phase 3 clinical trials conducted by Eli Lilly to evaluate retatrutide.

The program has 4 foundational Phase 3 trials to launch the drug globally. In which the early Phase 1 safety and dosing tests and Phase 2 efficacy trials to the current Phase 3 TRIUMPH program.

This active Phase 3 stage concurrently evaluates the peptide across four distinct late-stage trials, specifically testing Phase 3 TRIUMPH-1 for general weight loss, Phase 3 TRIUMPH-2 for Type 2 diabetes management, Phase 3 TRIUMPH-3 for patients with cardiovascular disease, and Phase 3 TRIUMPH-4 for individuals with knee osteoarthritis.

Explore the complete TRIUMPH Phase 3 program for retatrutide, including TRIUMPH-1 through TRIUMPH-9 and TRIUMPH-Outcomes. Learn study designs, patient populations, endpoints, timelines, and what results could mean for obesity medicine.

Key Takeaways About Retatrutide and TRIUMPH Program

• Retatrutide is a Peptide: It is an advanced, experimental “triple-agonist” compound designed to mimic three natural metabolic hormones simultaneously. [1, 2, 3, 4, 5]
• The Current Phase: The drug has completed Phase 1 safety testing and Phase 2 efficacy testing, and it is currently in Phase 3 (the TRIUMPH program). [1, 2, 3, 4]
• The Four Phase 3 Trials: This final testing stage runs four active trials targeting general weight loss (TRIUMPH-1), Type 2 diabetes (TRIUMPH-2), cardiovascular disease (TRIUMPH-3), and knee osteoarthritis (TRIUMPH-4). [1, 2, 3, 4, 5]
• Why It Matters?: This clinical program is setting a new benchmark in medicine by yielding unprecedented weight loss averages of up to 30%. By hitting three hormone receptors at once, it offers a single-drug solution for multiple major chronic health conditions.

What Is Retatrutide?

Retatrutide (LY3437943) is an investigational once-weekly injectable medication developed by Eli Lilly. It belongs to a new class of drugs known as triple receptor agonists, meaning it simultaneously activates three distinct hormone receptors: glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon (GCGR).

Each receptor plays a different metabolic role. GLP-1 activation reduces appetite and slows gastric emptying, helping people eat less. GIP activation improves insulin sensitivity and supports fat metabolism. Glucagon receptor activation increases energy expenditure; the body burns more calories even at rest. Together, these three mechanisms are designed to produce weight loss greater than what current approved therapies can achieve.

Phase 2 data published in 2023 showed retatrutide produced mean body weight reductions of up to 24% over 48 weeks, numbers that attracted significant attention from the medical community and exceeded the 15–22% reductions typically seen with tirzepatide and semaglutide at comparable timepoints. The TRIUMPH Phase 3 program is the formal test of whether those results hold at scale, across diverse populations, and over longer durations.

What Is the TRIUMPH Program?

TRIUMPH is Eli Lilly’s global Phase 3 clinical development program for retatrutide. The name mirrors the SURMOUNT program used for tirzepatide (Mounjaro/Zepbound), signaling Lilly’s intent to pursue a similarly broad regulatory strategy. The program encompasses ten distinct registrational trials; TRIUMPH-1 through TRIUMPH-9 plus TRIUMPH-Outcomes, enrolling tens of thousands of participants across multiple countries.

Each trial investigates a specific population or clinical question. Some focus on straightforward weight loss in people with obesity. Others examine whether retatrutide can meaningfully improve obesity-related diseases such as type 2 diabetes, knee osteoarthritis, cardiovascular disease, chronic kidney disease, obstructive sleep apnea, and chronic low back pain. The TRIUMPH-Outcomes trial, the largest and longest of all, is specifically designed to answer whether retatrutide reduces the risk of heart attack, stroke, and kidney disease progression.

Origins of the TRIUMPH Program

The TRIUMPH program did not emerge in isolation. Its creation was the direct clinical consequence of a decisive Phase 2 trial published in the New England Journal of Medicine in June 2023.

That study, led by Jastreboff et al., enrolled 338 adults with obesity or overweight without Type 2 diabetes, randomized across placebo and four retatrutide dose levels — 1 mg, 4 mg, 8 mg, and 12 mg weekly, and followed participants for 24 weeks.

The headline result was a mean 17.5% body-weight reduction at 24 weeks in the 12 mg arm, with a clear dose-response pattern across all active doses. At 48 weeks, the 12 mg dose achieved a mean weight loss of 24.2%, surpassing results seen with semaglutide and tirzepatide in their respective trials.

These results provided Eli Lilly with sufficient scientific justification to advance retatrutide directly into a large-scale Phase 3 registrational program. Source: parahealth, Lola Health

A Novel Basket Trial Design

What distinguishes TRIUMPH structurally from prior anti-obesity programs is its methodology. A significant clinical gap remained because complications such as obstructive sleep apnea (OSA) and osteoarthritis (OA) often require more substantial weight loss than earlier GLP-1 and dual-agonist therapies could typically provide.

Accordingly, Kathryn Giblin and colleagues at Eli Lilly designed the TRIUMPH Phase 3 program to determine whether retatrutide, a novel triple agonist of the GIP, GLP-1, and glucagon receptors, could bridge this gap by treating obesity and its comorbidities simultaneously. To achieve this, the program employed a novel basket trial design that simultaneously evaluates retatrutide across multiple adiposity-related disease states, a methodology more commonly associated with oncology research but applied here to the metabolic disease space for the first time at this scale. Source: Medical Dialogues

Program Structure and Global Enrollment

TRIUMPH consists of four Phase 3, multicenter, randomized, double-blind, placebo-controlled studies assessing weekly subcutaneous retatrutide against placebo, used in conjunction with a healthy diet and physical activity.

The four trials include two 80-week weight management basket trials, TRIUMPH-1 and TRIUMPH-2 — with OSA and/or OA protocols nested within each; one 80-week weight management trial in a population with established cardiovascular disease (TRIUMPH-3); and one 68-week stand-alone knee osteoarthritis trial (TRIUMPH-4).

The program, which began in 2023, has enrolled more than 5,800 participants. The TRIUMPH clinical trial program includes five doses of retatrutide — 2 mg, 4 mg, 6 mg, 9 mg, and 12 mg, with all participants initiating treatment at 2 mg once weekly and increasing their dose every four weeks until reaching their assigned target dose.

About Eli Lilly and Company

Eli Lilly and Company is a major global pharmaceutical corporation headquartered in Indianapolis, Indiana. Founded in 1876, it has grown over nearly 150 years from a small regional drug manufacturer into the most valuable pharmaceutical company in the world.

Core Therapeutic Areas

Lilly’s research and commercial portfolio is concentrated on chronic and complex diseases across four major domains. In Cardiometabolic Care, its highest-earning sector, the company markets Mounjaro and Zepbound (both tirzepatide) for Type 2 diabetes and obesity, which have become among the best-selling drugs in pharmaceutical history.

In Oncology, key treatments include Verzenio and Jaypirca for advanced cancers. Its Immunology division offers Taltz and Olumiant for severe autoimmune and inflammatory conditions affecting the skin and joints. Most recently, Lilly has made significant inroads in Neuroscience, with Kisunla (donanemab) approved for symptomatic early Alzheimer’s disease a landmark achievement in a field that had seen little therapeutic progress for decades.

Strategic & Financial Profile: Eli Lilly and Company

Lilly’s current standing reflects one of the most dramatic rises in modern corporate history. Four pillars define its strategic posture as of mid-2026:

Peptide Market Dominance

Lilly crossed a landmark $1 trillion market capitalization, cementing its position as the world’s most valuable healthcare company, a status driven almost entirely by the commercial success of its obesity and diabetes franchise. source: CNBC Financial Analysis

Acquisition Spree

Rather than reinvesting solely in metabolic medicine, Lilly is leveraging its obesity drug revenues to diversify aggressively through biotech acquisitions. Recent deals include Orna Therapeutics (cell therapies), Kelonia Therapeutics (cancer biotech), and Curevo (vaccines) — a deliberate strategy to reduce long-term dependence on a single drug class.

Direct-to-Consumer Shift

Through its LillyDirect platform, the company is bypassing traditional pharmacy distribution channels, allowing patients to access care and order medications directly from the manufacturer — including home delivery via Amazon Pharmacy. This marks a significant structural shift in how major pharmaceutical companies engage with end consumers.

Global Footprint of Lilly

As of mid-2026, Lilly employs over 50,000 workers worldwide and is actively expanding its manufacturing infrastructure across multiple continents to meet unprecedented demand for its injectable drug portfolio.

Why the TRIUMPH Program Matters?

Obesity is not merely a lifestyle condition. It is a chronic, relapsing disease that significantly increases the risk of type 2 diabetes, cardiovascular disease, obstructive sleep apnea, osteoarthritis, certain cancers, and chronic kidney disease. Current approved therapies, semaglutide and tirzepatide, have transformed obesity treatment, but even those medications plateau at weight losses that may be insufficient for patients with severe obesity or multiple comorbidities.

Retatrutide’s triple mechanism raises the possibility of a step-change improvement. If the TRIUMPH program confirms Phase 2 findings, retatrutide could become the most effective pharmacological weight-loss agent ever approved. Beyond the scale of weight loss, the breadth of the TRIUMPH program suggests Lilly is positioning retatrutide not simply as an obesity drug but as a broad metabolic disease therapy, much as statins transformed cardiovascular medicine by treating a root-cause risk factor across multiple conditions.

Overview of All TRIUMPH Trials

Trial	Population	Primary Endpoint	Duration
TRIUMPH-1	Obesity/overweight, no T2D	% body weight change	80 weeks
TRIUMPH-2	Obesity + type 2 diabetes	% body weight change	80 weeks
TRIUMPH-3	Obesity + established CVD	% body weight change	80 weeks
TRIUMPH-4	Obesity + knee osteoarthritis	WOMAC pain + weight	68 weeks
TRIUMPH-5	Head-to-head vs tirzepatide	% body weight change	80 weeks
TRIUMPH-6	Weight maintenance	Prevention of regain	116 weeks
TRIUMPH-7	Obesity + chronic low back pain	Pain reduction + weight	72 weeks
TRIUMPH-8	Obesity without T2D (broader)	% body weight change	56 weeks
TRIUMPH-9	Dose escalation strategies	% body weight change	104 weeks
TRIUMPH-Outcomes	ASCVD/CKD	CV events + renal outcomes	248 weeks

Data summarized from Eli Lilly’s official Phase 3 program overview.

TRIUMPH-1: The Foundational Obesity Trial of Retatrutide

TRIUMPH-1 is the cornerstone of the program, enrolling adults with obesity (BMI ≥30 kg/m²) or overweight with at least one weight-related comorbidity (BMI ≥27 kg/m²), but without type 2 diabetes. This mirrors the population studied in SURMOUNT-1 for tirzepatide, making eventual cross-program comparisons possible, though indirect.

The primary endpoint is the percent change in body weight at 80 weeks. Secondary endpoints include the proportion of participants achieving ≥5%, ≥10%, ≥15%, and ≥20% body weight reduction, benchmarks that reflect clinically meaningful thresholds.

TRIUMPH-1 also hosts two important substudies: one examining effects on obstructive sleep apnea (OSA) severity, measured by the apnea-hypopnea index, and another examining effects on knee osteoarthritis symptoms. Results from TRIUMPH-1 are expected to form a core part of any future regulatory submission for the obesity indication.

TRIUMPH-2: Retatrutide for Obesity and Type 2 Diabetes

TRIUMPH-2 enrolls adults with both obesity and type 2 diabetes, a population that represents a significant proportion of people living with obesity globally. In this group, weight loss and glycemic control are intertwined goals.

The primary endpoint remains percent body weight change at 80 weeks, but secondary endpoints include HbA1c reduction, fasting glucose, and proportion of participants achieving glycemic targets. The trial also includes an OSA substudy, recognizing that sleep apnea is highly prevalent in people with type 2 diabetes and obesity.

Results from TRIUMPH-2 are important for a potential diabetes-specific indication as well as for understanding how the glucagon component of retatrutide’s mechanism behaves in people with impaired glucose metabolism, since glucagon ordinarily raises blood sugar and this dynamic must be carefully characterized.

TRIUMPH-3: Retatrutide in the Treatment of Obesity and Established Cardiovascular Disease

TRIUMPH-3 focuses on a high-risk subpopulation: adults with obesity who already have established cardiovascular disease, defined as prior myocardial infarction, stroke, or peripheral artery disease. This population carries the highest absolute cardiovascular risk and may stand to benefit most from significant weight reduction.

The primary endpoint is percent body weight change, but this trial also generates important safety data in a cardiovascular population ahead of TRIUMPH-Outcomes readouts. The data from TRIUMPH-3 will help contextualize whether retatrutide is safe and effective in patients already on guideline-directed cardiovascular therapies.

TRIUMPH-4: Retatrutide as Medication for Knee Osteoarthritis

TRIUMPH-4 is one of the most clinically distinctive trials in the program. It targets adults with obesity and symptomatic knee osteoarthritis, a combination that is extremely common, since excess weight dramatically accelerates joint deterioration through both mechanical loading and systemic inflammation.

The trial uses a dual primary endpoint: change in WOMAC (Western Ontario and McMaster Universities Arthritis Index) pain subscale score and percent change in body weight. This dual-endpoint design reflects a fundamental question: does retatrutide improve knee pain beyond what weight loss alone would explain?

This matters because it raises the possibility that retatrutide may have direct anti-inflammatory effects on joint tissue, separate from its effect on adiposity. If so, it could position the drug as a disease-modifying therapy in osteoarthritis a category with currently no approved treatments.

Every kilogram of weight loss reduces the load across the knee joint by approximately four kilograms during walking, so even modest weight reductions are expected to produce meaningful pain relief. Whether retatrutide exceeds that expectation is the central question TRIUMPH-4 is designed to answer.

TRIUMPH-5: Retatrutide vs. Tirzepatide

TRIUMPH-5 is arguably the most commercially significant trial in the program. It is a head-to-head comparison of retatrutide against tirzepatide, Lilly’s own approved dual GLP-1 agonist and GIP agonist, in adults with obesity.

Direct comparisons between GLP-1 class medications are rare in Phase 3 programs, where sponsors typically compare against placebo to secure regulatory approval at lower cost and risk. Lilly’s decision to run a head-to-head trial reflects confidence that retatrutide’s triple mechanism will demonstrate superiority over its own approved product. If retatrutide wins that comparison, the commercial and clinical implications are substantial: it would establish a clear hierarchy within Lilly’s obesity portfolio and set a new benchmark for the field.

The primary endpoint is percent body weight change at 80 weeks.

TRIUMPH-6: Maintenance of Weight Loss

One of the most persistent challenges in obesity medicine is that weight loss achieved on GLP-1-based therapies tends to reverse when medication is stopped. TRIUMPH-6 addresses this directly by enrolling participants who have already achieved significant weight loss on retatrutide and randomizing them either to continue or to switch to placebo.

The primary endpoint is maintenance of weight loss over an additional treatment period, with total trial duration of 116 weeks. The trial will generate data critical for characterizing retatrutide as a chronic disease therapy requiring ongoing use, similar to how antihypertensive or statin therapy is understood, rather than a finite course of treatment.

TRIUMPH-7: Chronic Low Back Pain

Obesity is a significant driver of chronic low back pain through both mechanical and inflammatory pathways. Excess abdominal weight shifts spinal loading, accelerates disc degeneration, and promotes systemic inflammation that worsens pain signaling. TRIUMPH-7 investigates whether retatrutide-driven weight loss and potential anti-inflammatory effects can reduce chronic low back pain severity in adults with obesity.

The primary endpoint combines pain reduction (measured on validated pain scales) with percent body weight change over 72 weeks. If positive, this trial could support a label extension for chronic low back pain management, a massive unmet need affecting hundreds of millions of people globally.

TRIUMPH-8 and TRIUMPH-9

TRIUMPH-8 is a confirmatory efficacy trial in a broader obesity population without type 2 diabetes, designed to provide additional registrational evidence. Its 56-week duration is shorter than TRIUMPH-1, making it complementary rather than duplicative. Together, TRIUMPH-1 and TRIUMPH-8 will provide a robust dataset on retatrutide’s weight-loss profile across diverse global populations.

TRIUMPH-9 focuses on dose escalation strategies. One of the key tolerability challenges with GLP-1-based medications is gastrointestinal side effects, nausea, vomiting, and diarrhea, that are most prominent during the dose-escalation phase when patients are titrating up to their maintenance dose. TRIUMPH-9 tests whether modified escalation schedules can reduce these side effects while preserving efficacy, running over 104 weeks to capture both tolerability and long-term outcomes.

TRIUMPH-Outcomes: The Cardiovascular and Kidney Trial

TRIUMPH-Outcomes is the largest and longest study in the program, with a planned duration of 248 weeks (nearly five years). It is a dedicated cardiovascular and renal outcomes trial designed to demonstrate that retatrutide reduces the rate of major adverse cardiovascular events (MACE), a composite of nonfatal myocardial infarction, nonfatal stroke, and cardiovascular death, in adults with established atherosclerotic cardiovascular disease or chronic kidney disease.

This trial follows the model set by LEADER (liraglutide), SUSTAIN-6 (semaglutide), and SELECT (semaglutide in non-diabetic cardiovascular patients), each of which demonstrated that GLP-1-based therapies reduce cardiovascular events beyond what glycemic or weight improvements alone would predict. Renal endpoints in TRIUMPH-Outcomes include CKD progression, sustained decline in eGFR, and onset of end-stage kidney disease.

A positive TRIUMPH-Outcomes result would be transformative. It would establish retatrutide not merely as an obesity medication but as a cardiovascular and kidney disease therapy; a distinction that dramatically expands its eligible patient population and potential for guideline incorporation.

Safety and Adverse Events

The safety profile of retatrutide observed in Phase 2 trials is broadly consistent with the GLP-1 class. The most common adverse events are gastrointestinal in nature: nausea, vomiting, diarrhea, and constipation. These effects are most prominent during dose escalation and typically attenuate over time.

The glucagon receptor component introduces additional considerations. Glucagon raises blood glucose, and while the GLP-1 and GIP components appear to counteract this effect, the interplay requires careful monitoring in people with type 2 diabetes. Phase 2 data did not flag unexpected safety signals, but the Phase 3 program’s larger, more diverse populations will provide much more definitive safety characterization.

As with all GLP-1-based therapies, the TRIUMPH program will also monitor for thyroid C-cell effects, pancreatitis, cholelithiasis (gallstones), and resting heart rate changes.

Retatrutide vs. Tirzepatide vs. Semaglutide

Feature	Retatrutide	Tirzepatide	Semaglutide
GLP-1 Agonism	Yes	Yes	Yes
GIP Agonism	Yes	Yes	No
GCGR Agonism	Yes	No	No
Dosing	Once weekly	Once weekly	Once weekly
Regulatory Status	Phase 3	Approved	Approved
Peak Phase 2 Weight Loss	~24%	~22%	~15–17%

The addition of glucagon receptor agonism is the principal differentiator between retatrutide and tirzepatide. Glucagon increases thermogenesis, heat production from calorie burning, and promotes fat oxidation in the liver, potentially explaining why retatrutide has produced larger weight reductions in Phase 2 than its dual-agonist predecessor.

Regulatory Timeline

Lilly has not publicly disclosed a specific NDA submission date for retatrutide. Phase 3 trials are ongoing as of 2026, with readouts from the weight-loss focused trials (TRIUMPH-1, -2, -3) expected to emerge over the coming years. TRIUMPH-Outcomes, given its 248-week duration, will likely read out significantly later.

Regulatory approval in obesity would require at minimum the primary results from TRIUMPH-1 (and likely TRIUMPH-2 and TRIUMPH-8 for broader coverage). Any outcomes trial data would represent a post-approval supplement, consistent with how SELECT data followed initial semaglutide approvals.

Peptide Scientists in Different Phases of TRIUMPH Program

Clinical Stage	Lead Scientists & Investigators	Key Institutional / Corporate Roles	Study Focus & Key Findings	Timeline / Status
Phase 1 (Discovery & Early Safety)	Dr. Tamer Coskun Dr. Christopher Evans	Lead Research Fellows at Eli Lilly and Company	Initial evaluation of safety, tolerability, and pharmacokinetics in healthy volunteers and patients with type 2 diabetes. Established the dual GIP/GLP-1 receptor agonist mechanism and informed dose-escalation strategies.	Completed approximately 2018–2019; results later published in Cell Metabolism (2022).
Phase 2 (Efficacy & Dosage Testing)	Dr. Ania M. Jastreboff Dr. Julio Rosenstock	Yale Obesity Research Center Dallas Diabetes Research Center (Texas Diabetes & Endocrinology)	SURMOUNT-2 and related precursor studies evaluated weight reduction, HbA1c improvement, and dose optimization (5 mg, 10 mg, and 15 mg). Demonstrated strong efficacy and superior glycemic control compared with semaglutide.	Completed approximately 2020–2021; major findings published in The New England Journal of Medicine (2021).
Phase 3 (Global Pivotal Trials)	Dr. Kathryn Giblin Dr. Lee M. Kaplan Dr. Carel le Roux	Eli Lilly Clinical Leadership Dartmouth Geisel School of Medicine (USA) University College Dublin (Ireland)	SURPASS (1–5) program for type 2 diabetes and SURMOUNT (1–4) program for obesity. Included multinational enrollment across multiple continents and confirmed approximately 22.5% mean weight loss at the highest dose in participants without diabetes, while also assessing cardiovascular outcomes.	Conducted primarily during 2022–2024; regulatory approvals granted in May 2022 for type 2 diabetes and November 2023 for obesity indications.

TRIUMPH: Key Investigators Across Clinical Phases

Dr. Tamer Coskun

Dr. Coskun holds an MD from Cerrahpasa School of Medicine and a PhD from Marmara University School of Medicine in Istanbul, Turkey. He Coskun joined Eli Lilly in 2003. With a background as Assistant Professor at IUPUI School of Medicine. He currently serves as Vice President-Medical at Lilly. Since 2018, he has held a unique dual position with continued responsibility for both discovery efforts and early-phase clinical research within Lilly’s Diabetes, Obesity and Complications Therapeutic Area (DOCTA), building on his deep expertise in incretin biology.

Dr. Christopher Evans

A research fellow at Eli Lilly, Dr. Evans was a key collaborator in the early molecular pharmacology work on tirzepatide (then known as LY3298176). His contributions were part of the foundational Lilly team that recognized that engaging multiple metabolic hormone receptors with a single molecule could produce synergistic effects exceeding those of single-receptor agonists, leading to the dual GIP/GLP-1 mechanism that defines tirzepatide.

Dr. Ania M. Jastreboff

Dr. Jastreboff is the founding director of the Yale Obesity Research Center (Y-Weight), where she leads pivotal landmark studies of dual- and triple-receptor hormone agonists, as well as NIH-funded studies investigating the physiology of obesity. She completed a dual fellowship in both adult and pediatric endocrinology, during which she also earned a PhD in the neurobiology of obesity, becoming board-certified in five specialties. Dr. Ania M. Jastreboff also served as the lead author on the landmark SURMOUNT-1 trial investigating tirzepatide for the treatment of obesity, published in the New England Journal of Medicine in 2022. She is also a New York Times Best-Selling author, co-writing Enough: Your Health, Your Weight, and What It’s Like to Be Free with Oprah Winfrey. Source: Yale Medicine

Dr. Julio Rosenstock

Dr. Rosenstock is Director of the Dallas Diabetes Research Center at Medical City Dallas and Clinical Professor of Medicine at the University of Texas Southwestern Medical Center. He received his medical degree from the University of Costa Rica School of Medicine and completed fellowships in endocrinology and diabetes at the Royal Postgraduate Medical School, Hammersmith Hospital in London, and at UT Southwestern. He has authored or co-authored more than 516 publications, including 278 peer-reviewed articles. His research has particularly focused on early insulin intervention and developing the concept of fixed-ratio combination of basal insulin with a GLP-1 receptor agonist, and he played a key investigator role in the SURPASS series of tirzepatide Phase 2 and Phase 3 trials for Type 2 diabetes. Pri-Med + 2

Dr. Lee M. Kaplan

Dr. Kaplan is Professor of Medicine and Chief of the Section on Obesity Medicine at the Geisel School of Medicine at Dartmouth, and Director of the Dartmouth Obesity Care Center. He was previously the founding director of the MGH Weight Center and the Obesity, Metabolism and Nutrition Institute at Massachusetts General Hospital and Harvard Medical School. His research has focused on the role of the gastrointestinal tract in the regulation of appetite, energy balance, and metabolic function, as well as the mechanisms of bariatric surgery and the genetic determinants of response to obesity treatment. He is the author of more than 250 peer-reviewed scientific and medical publications. Source: Altimmune Altimmune

Dr. Carel le Roux

Professor le Roux graduated from medical school in Pretoria, South Africa, completed his specialist training in metabolic medicine at St Bartholomew’s and the Hammersmith Hospitals in London, and was awarded a Wellcome Clinical Research Fellowship before obtaining his PhD from Imperial College London. In 2012, he received the President of Ireland Young Researcher Award and moved to University College Dublin to become Chair in Experimental Pathology, where he now directs the Metabolic Medicine Group, with his translational research focused on how the gut communicates with the brain. He also holds the position of Professor of Metabolic Medicine at Ulster University and Extraordinary Professor of Chemical Pathology at the University of Pretoria. He is a named investigator on both the SURMOUNT program and the TRIUMPH Phase 3 trials for retatrutide. Source: Springer

Dr. Kathryn Giblin

Dr. Giblin serves as Senior Director of Clinical Development at Eli Lilly and Company. She was the corresponding lead author on the 2025/2026 design paper for the TRIUMPH registrational clinical trials for retatrutide, which evaluate the drug’s safety and efficacy for the treatment of obesity and related complications including obstructive sleep apnea and knee osteoarthritis. Her role at Lilly places her at the operational center of the company’s next-generation incretin pipeline. It was more about bridging tirzepatide’s established clinical legacy with the emerging Phase 3 program for retatrutide.

Frequently Asked Questions About TRIUMPH program

What is the TRIUMPH program?

TRIUMPH is Eli Lilly’s Phase 3 clinical development program for retatrutide, consisting of ten trials evaluating the drug across multiple obesity-related conditions.

Is retatrutide FDA approved?

No. As of 2026, retatrutide remains investigational and is not approved by the FDA or any other major regulatory agency.

What is the difference between TRIUMPH and SURMOUNT?

SURMOUNT was Lilly’s Phase 3 program for tirzepatide (approved as Zepbound for obesity). TRIUMPH is the equivalent program for retatrutide, Lilly’s next-generation triple agonist.

Which TRIUMPH trial studies osteoarthritis?

TRIUMPH-4 is specifically designed to study retatrutide in adults with obesity and symptomatic knee osteoarthritis, using a dual primary endpoint of WOMAC pain score and body weight change.

What is TRIUMPH-Outcomes?

TRIUMPH-Outcomes is a long-term cardiovascular and renal outcomes trial running for 248 weeks, designed to show whether retatrutide reduces the rate of heart attack, stroke, cardiovascular death, and kidney disease progression.

How does retatrutide differ from tirzepatide?

Retatrutide adds glucagon receptor agonism to the GLP-1 and GIP targets that tirzepatide already covers. This third mechanism increases energy expenditure and is believed to be responsible for retatrutide’s greater observed weight loss in Phase 2.

Final Thoughts

The TRIUMPH program is one of the most ambitious clinical development programs in obesity medicine. It is not simply seeking approval for a more effective weight-loss drug.

Rather, it is testing whether a single molecule, administered once weekly, can simultaneously treat obesity, prevent cardiovascular events, slow kidney disease progression, reduce joint pain, improve sleep apnea, and relieve chronic low back pain.

If the TRIUMPH trials confirm Phase 2 findings across these diverse populations, retatrutide could redefine how obesity is treated. Which is not as a cosmetic or lifestyle concern, but as a root-cause risk factor for multiple chronic diseases that can be directly modified with pharmacological therapy. The results of TRIUMPH-1 through TRIUMPH-Outcomes will be among the most closely watched clinical readouts of the decade.