Updated September 4, 2026
Retatrutide is no longer a drug candidate supported by one or two promising trials.
Eli Lilly has built a broad clinical development program around the investigational triple hormone receptor agonist, testing it across obesity, type 2 diabetes, cardiovascular disease, chronic kidney disease, obstructive sleep apnea, knee osteoarthritis, chronic low back pain, long-term weight maintenance, and different dosing strategies.
That program is mainly organized under two names: TRIUMPH and TRANSCEND.
The original TRIUMPH program consisted of four Phase 3 registrational trials involving more than 5,800 participants. Since then, Lilly has added head-to-head, maintenance, pain, dosing, escalation, and cardiovascular outcome studies. The TRANSCEND program focuses more heavily on type 2 diabetes and kidney-related questions.
Some of these studies now have results. Others will not report for several years.
And their publication status matters. As of September 2026, some findings have been published in peer-reviewed journals, some have been presented at scientific meetings, and others exist only as topline company reports.
Here is where the entire retatrutide clinical trial pipeline stands.
TL;DR: The Retatrutide Trial Pipeline
The first four TRIUMPH trials established the main Phase 3 obesity program. TRIUMPH-1 tested obesity without diabetes and also included knee osteoarthritis and obstructive sleep apnea substudies. TRIUMPH-2 studied obesity or overweight with type 2 diabetes. TRIUMPH-3 focused on severe obesity with established cardiovascular disease. TRIUMPH-4 specifically tested obesity with knee osteoarthritis.
Since then, Lilly has added TRIUMPH-5 through TRIUMPH-9 and TRIUMPH-Outcomes.
TRANSCEND-T2D-1 has already produced the first peer-reviewed Phase 3 retatrutide efficacy paper. TRANSCEND-T2D-2 is comparing retatrutide directly with semaglutide, while TRANSCEND-T2D-3 is studying people with type 2 diabetes, renal impairment, and basal insulin use. TRANSCEND-CKD is a smaller mechanistic kidney study.
The pipeline now extends well beyond the question of whether retatrutide reduces body weight.
Retatrutide Clinical Trials at a Glance
| Trial | Main Population | Main Question | Status as of Sept. 2026 |
|---|---|---|---|
| TRIUMPH-1 | Obesity/overweight, no T2D | Weight loss; OA and OSA baskets | Results reported/presented |
| TRIUMPH-2 | Obesity/overweight + T2D | Weight loss | Topline results reported |
| TRIUMPH-3 | Severe obesity + CVD | Weight loss; CV analyses | Topline results reported |
| TRIUMPH-4 | Obesity/overweight + knee OA | Weight loss + knee pain | Topline results reported |
| TRIUMPH-5 | Obesity | Retatrutide vs. tirzepatide | Active, not recruiting |
| TRIUMPH-6 | Obesity | Maintenance of weight loss | Active, not recruiting |
| TRIUMPH-7 | Obesity/overweight + chronic low back pain | Pain + weight loss | Active, not recruiting |
| TRIUMPH-8 | Obesity/overweight, no T2D | Alternative dosing study | Active, not recruiting |
| TRIUMPH-9 | Obesity/overweight, no T2D | Dose-escalation strategies | Active, not recruiting |
| TRIUMPH-Outcomes | ASCVD and/or CKD | Cardiovascular + kidney events | Active, not recruiting |
| TRANSCEND-T2D-1 | Early T2D controlled with diet/exercise | A1C | Completed; peer reviewed |
| TRANSCEND-T2D-2 | T2D on metformin ± SGLT2i | Retatrutide vs. semaglutide | Active, not recruiting |
| TRANSCEND-T2D-3 | T2D + renal impairment + basal insulin | A1C | Active, not recruiting |
| TRANSCEND-CKD | Overweight/obesity + CKD | Kidney physiology | Completed; design paper published |
TRIUMPH-1: The Main Phase 3 Obesity Trial
ClinicalTrials.gov: NCT05929066
TRIUMPH-1 is the centerpiece of the retatrutide obesity program.
It randomized 2,339 adults with obesity or overweight to retatrutide 4 mg, 9 mg, 12 mg, or placebo. Participants did not have type 2 diabetes. The master protocol also contained separate basket studies for knee osteoarthritis and moderate-to-severe obstructive sleep apnea.
The main endpoint was percentage change in body weight at week 80.
Using Lilly’s efficacy estimand, average weight changes were:
| Group | Weight Change at Week 80 |
|---|---|
| Retatrutide 4 mg | -19.0% |
| Retatrutide 9 mg | -25.9% |
| Retatrutide 12 mg | -28.3% |
| Placebo | -2.2% |
A prespecified extension followed 532 participants with baseline BMI of at least 35 through week 104. Participants continuing from the 12 mg arm reached an average weight reduction of 30.3% under the efficacy estimand.
The detailed TRIUMPH-1 results were presented at the American Diabetes Association Scientific Sessions in June 2026. They have not yet appeared as a full peer-reviewed outcomes paper as of this update.
TRIUMPH-2: Obesity With Type 2 Diabetes
ClinicalTrials.gov: NCT05929079
TRIUMPH-2 asked a different question: how does retatrutide perform when obesity or overweight occurs alongside type 2 diabetes?
Lilly randomized 1,152 participants to retatrutide 4 mg, 9 mg, 12 mg, or placebo. The primary weight endpoint was evaluated at week 80.
The reported efficacy-estimand weight changes were:
| Group | Weight Change |
|---|---|
| Retatrutide 4 mg | -12.7% |
| Retatrutide 9 mg | -19.1% |
| Retatrutide 12 mg | -20.8% |
| Placebo | -4.0% |
A1C fell by as much as 1.6 percentage points among the retatrutide groups.
This population matters because it should not be treated as interchangeable with the non-diabetes population in TRIUMPH-1.
Lilly announced topline TRIUMPH-2 results in July 2026. Detailed peer-reviewed results have not yet been published.
TRIUMPH-3: Severe Obesity and Established Cardiovascular Disease
ClinicalTrials.gov: NCT05882045
TRIUMPH-3 moved into a higher-risk population.
Participants had a BMI of at least 35 kg/m² and established cardiovascular disease, including conditions such as prior myocardial infarction, stroke, or symptomatic peripheral artery disease. ClinicalTrials.gov records an actual enrollment of roughly 1,950 participants.
The primary endpoint was percentage change in body weight at week 80.
Reported efficacy-estimand changes were:
| Group | Weight Change |
|---|---|
| Retatrutide 9 mg | -21.6% |
| Retatrutide 12 mg | -22.6% |
| Placebo | -3.2% |
The study also collected cardiovascular-event data, but it was not the large event-driven outcomes trial designed to definitively establish cardiovascular benefit. The confidence intervals around the reported MACE analyses remained wide and included no effect.
That distinction is why TRIUMPH-Outcomes remains so important.
Lilly reported topline TRIUMPH-3 results in July 2026. A full peer-reviewed results paper is still pending.
TRIUMPH-4: Weight Loss and Knee Osteoarthritis Pain
ClinicalTrials.gov: NCT05931367
TRIUMPH-4 is one of the most interesting trials because body weight was only half of the story.
The 445 participants had obesity or overweight plus knee osteoarthritis and did not have diabetes. They were randomized to retatrutide 9 mg, 12 mg, or placebo.
The trial had co-primary endpoints at week 68:
body-weight change and change in WOMAC knee pain score.
The efficacy-estimand weight results were 26.4% reduction with 9 mg and 28.7% with 12 mg, compared with 2.1% with placebo.
WOMAC pain scores fell by 4.5 points with 9 mg and 4.4 points with 12 mg, versus 2.4 points with placebo.
TRIUMPH-4 was completed in November 2025. Lilly released topline results in December 2025, but the full trial results have not yet appeared as a peer-reviewed outcomes publication.
TRIUMPH-5: Retatrutide vs. Tirzepatide
ClinicalTrials.gov: NCT06662383
TRIUMPH-5 may eventually be one of the most important studies in the entire program.
Instead of comparing retatrutide with placebo, this trial directly compares it with tirzepatide.
Approximately 800 adults with obesity are being studied in a randomized, double-blind Phase 3 trial. The primary endpoint is percentage change in body weight at week 80.
That makes TRIUMPH-5 much more informative than comparing retatrutide and tirzepatide results from separate studies.
As of September 2026, the trial is active but no longer recruiting. Primary completion is estimated for December 2026.
No results are available yet.
TRIUMPH-6: Can Retatrutide Maintain Weight Loss?
ClinicalTrials.gov: NCT06859268
TRIUMPH-6 tackles a question that becomes more important as obesity drugs produce larger reductions in weight:
What happens during long-term maintenance?
Approximately 643 participants enter an 80-week retatrutide lead-in period. They then move into a 36-week randomized phase in which treatment is continued, altered, or replaced with placebo.
The primary endpoint is percentage change in body weight from week 0 through week 116. A key secondary measure looks at how much of the weight reduction achieved by week 80 remains at week 116.
The study is active, not recruiting, with completion currently estimated in April 2028. No results have been posted.
TRIUMPH-7: Chronic Low Back Pain
ClinicalTrials.gov: NCT07035093
TRIUMPH-7 expands the obesity-complication strategy into chronic low back pain.
Approximately 586 adults with obesity or overweight and chronic low back pain are being studied.
Unlike a conventional obesity trial, this study has two major clinical questions. It measures both change in pain intensity and percentage change in body weight through approximately week 72. Secondary measures include physical function, pain interference, sleep, inflammatory biomarkers, blood pressure, and metabolic outcomes.
As of the latest ClinicalTrials.gov update, TRIUMPH-7 is active but no longer recruiting. Completion is estimated for September 2027, and no results have been posted.
TRIUMPH-8: Another Phase 3b Obesity Study
ClinicalTrials.gov: NCT07232719
TRIUMPH-8 is a smaller Phase 3b trial involving about 250 adults with obesity or overweight who do not have type 2 diabetes.
The primary endpoint is percentage change in body weight at week 56. Secondary endpoints include waist circumference, systolic blood pressure, non-HDL cholesterol, and pharmacokinetic exposure.
Lilly’s development materials describe this part of the expanded program as exploring additional dosing options rather than simply repeating the original TRIUMPH-1 design.
The trial is active, not recruiting, with estimated completion in July 2027.
TRIUMPH-9: Testing Different Dose-Escalation Strategies
ClinicalTrials.gov: NCT07357415
TRIUMPH-9 was added after the original program and is important for a different reason: tolerability and escalation strategy.
The approximately 600-participant Phase 3b trial compares different retatrutide dose-escalation schemes in adults with obesity or overweight and without type 2 diabetes.
Its primary outcome is percentage change in body weight at week 104. Secondary outcomes include waist circumference, triglycerides, systolic blood pressure, hsCRP, quality of life, treatment satisfaction, and pharmacokinetics.
This study may help determine whether different escalation schedules can preserve efficacy while improving practical tolerability.
It is active, not recruiting, with estimated completion in late 2028.
TRIUMPH-Outcomes: The Cardiovascular and Kidney Outcome Trial
ClinicalTrials.gov: NCT06383390
TRIUMPH-Outcomes is fundamentally different from a weight-loss trial.
It is an event-driven Phase 3 study expected to include around 10,000 adults with BMI of at least 27 kg/m² and established atherosclerotic cardiovascular disease and/or chronic kidney disease. Participants may have type 2 diabetes, but diabetes is not required.
Its primary cardiovascular composite includes nonfatal myocardial infarction, nonfatal stroke, cardiovascular death, and hospitalization or an urgent visit for heart failure.
A separate primary kidney composite includes end-stage kidney disease, sustained decline in eGFR, cardiovascular death, or renal death.
This is the study that can answer a question the shorter TRIUMPH trials cannot:
Does retatrutide actually reduce major cardiovascular and kidney events, rather than simply improving cardiovascular risk markers?
The trial is active, not recruiting, with estimated completion in February 2029.
TRANSCEND-T2D-1: The First Peer-Reviewed Phase 3 Retatrutide Results
ClinicalTrials.gov: NCT06354660
TRANSCEND-T2D-1 studied 537 adults with type 2 diabetes inadequately controlled by diet and exercise alone.
Participants received retatrutide 4 mg, 9 mg, 12 mg, or placebo for 40 weeks.
The primary endpoint was change in A1C.
Unlike the TRIUMPH results discussed above, TRANSCEND-T2D-1 has already been fully published in The Lancet.
Using the treatment-regimen estimand, average A1C changes were -1.69, -1.86, and -1.94 percentage points across the three retatrutide groups, compared with -0.81 with placebo. Body weight fell by 11.5%, 13.9%, and 15.3%, respectively, versus 2.6% with placebo.
This currently provides the strongest fully peer-reviewed Phase 3 evidence for retatrutide.
TRANSCEND-T2D-2: Retatrutide vs. Semaglutide
ClinicalTrials.gov: NCT06260722
TRANSCEND-T2D-2 is another important head-to-head study.
Approximately 1,250 adults with type 2 diabetes inadequately controlled with metformin, with or without an SGLT2 inhibitor, are being randomized to retatrutide or semaglutide.
The primary endpoint is change in A1C at week 80. Body-weight change is among the key secondary measures.
ClinicalTrials.gov currently lists the trial as active, not recruiting. Primary completion had been estimated for August 2026, while overall study completion is estimated for January 2027.
As of September 4, 2026, no public efficacy results have been posted.
TRANSCEND-T2D-3: Type 2 Diabetes With Renal Impairment and Basal Insulin
ClinicalTrials.gov: NCT06297603
TRANSCEND-T2D-3 addresses a more medically complex diabetes population.
Participants have type 2 diabetes, moderate or severe renal impairment, and inadequate glycemic control despite basal insulin. Metformin and/or an SGLT2 inhibitor may also be used.
The study is expected to include around 320 participants.
Its primary endpoint is change in A1C at week 52. Secondary measures include fasting glucose, continuous-glucose-monitoring time in range, body weight, triglycerides, non-HDL cholesterol, and systolic blood pressure.
The study remains active but no longer recruiting. Primary completion is estimated for October 2026, with study completion expected in November.
TRANSCEND-CKD: A Mechanistic Kidney Study
ClinicalTrials.gov: NCT05936151
TRANSCEND-CKD is a smaller Phase 2b study rather than part of the Phase 3 diabetes registration program.
It enrolled 146 adults with overweight or obesity and chronic kidney disease, with or without type 2 diabetes.
The primary endpoint was change in measured glomerular filtration rate using iohexol clearance at week 24. Researchers also evaluated albuminuria, renal blood flow, MRI-based kidney measurements, sodium handling, and body weight.
The study is completed.
A peer-reviewed paper published in 2026 describes its rationale, design, and baseline characteristics, but does not yet provide the primary efficacy results.
This mechanistic study complements the much larger clinical-outcomes questions being tested in TRIUMPH-Outcomes.
Why Publication Status Matters
It is tempting to put every Phase 3 percentage into one table and treat all of it as equally established.
It is not.
The strongest current publication status belongs to TRANSCEND-T2D-1, which has a full peer-reviewed Phase 3 publication.
The original TRIUMPH trial designs also have a peer-reviewed methods paper.
But the major TRIUMPH-1 through TRIUMPH-4 efficacy findings currently come from conference presentations and company-reported Phase 3 results rather than completed peer-reviewed outcome manuscripts.
TRIUMPH-2 and TRIUMPH-3 are particularly recent. Lilly stated when it announced them in July 2026 that detailed results would subsequently be presented at scientific meetings and submitted for peer-reviewed publication.
That does not make the results meaningless. It simply means the evidence is still moving through the publication process.
What Comes Next for Retatrutide?
Lilly said in July 2026 that it had obtained the clinical data package needed to support global submissions for obesity, knee osteoarthritis pain, and obstructive sleep apnea, and that it plans to submit a U.S. Biologics License Application for retatrutide in the first quarter of 2027.
But the development program will continue well beyond an initial regulatory submission.
TRIUMPH-5 should give the first major direct comparison with tirzepatide. TRIUMPH-6 will help answer what happens during long-term maintenance. TRIUMPH-7 explores chronic low back pain. TRIUMPH-8 and TRIUMPH-9 test additional dosing and escalation strategies. And TRIUMPH-Outcomes will eventually provide the most important evidence on hard cardiovascular and kidney outcomes.
Retatrutide therefore should not be viewed as having one Phase 3 result.
It has become a broad clinical development program designed to test whether triple GIP, GLP-1, and glucagon receptor agonism can affect multiple diseases associated with obesity and metabolic dysfunction.
And because several key trials are still active, this is an article worth updating regularly.
References
ClinicalTrials.gov. TRIUMPH-1, NCT05929066. View TRIUMPH-1 trial record
Giblin K, et al. Retatrutide for the treatment of obesity, obstructive sleep apnea and knee osteoarthritis: Rationale and design of the TRIUMPH registrational clinical trials. Diabetes, Obesity and Metabolism. View on PubMed
Bajaj HS, et al. Efficacy and safety of retatrutide in people with type 2 diabetes: TRANSCEND-T2D-1. The Lancet. 2026. View on PubMed
ClinicalTrials.gov. TRIUMPH-5, NCT06662383. View TRIUMPH-5
ClinicalTrials.gov. TRIUMPH-6, NCT06859268. View TRIUMPH-6
ClinicalTrials.gov. TRIUMPH-Outcomes, NCT06383390. View TRIUMPH-Outcomes
ClinicalTrials.gov. TRANSCEND-T2D-2, NCT06260722. View TRANSCEND-T2D-2
ClinicalTrials.gov. TRANSCEND-T2D-3, NCT06297603. View TRANSCEND-T2D-3