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World Obesity Day 2025: Recent Developments and the Road Ahead

  • March 4, 2025

March 4th marks World Obesity Day, a unified day of action that calls for a cohesive, cross-sector response to the obesity crisis. The past year has been transformative for obesity research and treatment, with new therapies, evolving diagnostic frameworks, and updated regulatory guidelines shaping the landscape. As we reflect on the latest developments and anticipate what’s ahead, it’s clear that scientific innovation is redefining how we approach obesity management. In this blog, we aim to summarize the major events of 2024 and outline key developments anticipated in 2025.

Author: Yulia Lurye, MD
Sr. Medical Director,
Medical Deprtment, Medpace

Regulatory Updates: FDA, EMA, and NICE

FDA Guidance

In January 2025, the FDA released updated guidance titled “Obesity and Overweight: Developing Drugs and Biological Products for Weight Reduction.” The FDA continues to define eligiblility for clinical trials populations using BMI thresholds (>27 with comorbidities or >30 without). A summary of the key changes compared to the 2007 guidance can be found in this newly-published blog.

EMA Guidance

In Europe, the “Guideline on clinical evaluation of medicinal products used for weight management” from June 23, 2016, remains in use. Feedback on the December 2024 revision of the addendum for pediatric weight control medicinal products is being collected.

Meanwhile, the EMA organized a multistakeholder workshop addressing shortages of GLP-1 receptor agonists, which took place on July 1, 2024. The European Shortages Monitoring Platform to fully launched in February 2025. Novo Nordisk and Eli Lilly have responded to shortages by expanding manufacturing capacity. Both companies expect significantly improved availability of GLP-1 receptor agonists by 2025.

NICE Guidance

In December 2024, NICE issued new guidance recommending tirzepatide for adults with a BMI over 35 and at least one weight-related condition. This followed earlier criteria established for semaglutide and liraglutide. The BMI threshold over 35 kg/m² and at least one weight-related condition applies to initiating tirzepatide, semaglutide, and liraglutide in NICE’s Guideline NG246: “Overweight and Obesity Management”, published on January 14, 2025.

Advances in Obesity Definitions and Concepts

New Clinical Frameworks

New definitions and frameworks for obesity have been proposed. The Lancet Diabetes and Endocrinology Commission introduced a definition of clinical obesity and an algorithm to differentiate between preclinical and clinical obesity. The European Association for the Study of Obesity (EASO) released an updated framework for diagnosing, staging, and managing obesity as an adiposity-based chronic disease. Both frameworks agree that BMI alone is insufficient for diagnosing obesity, and that anthropometrical component should be complemented by clinical component.  The Lancet commission offers a third component of obesity as a disease – impairment of day-to-day activities. The EASO also emphasizes the importance of clinical staging of obesity.

BMI ranges were removed from FDA labels for weight management products, Wegovy® and Zepbound®. Additionally, both the FDA and EMA have approved updates to the Wegovy® label to reflect cardiovascular risk reduction data from the SELECT and STEP HFpEF trials.

Highlights of 2024 and Early 2025 Clinical Trial Results

  • Semaglutide (sc): The FLOW study, which was stopped early after meeting pre-specified efficacy criteria in an interim analysis, showed a 24% reduction in major kidney disease events and an 18% reduction in MACE over three years compared to placebo.1 New data from the STEP UP study demonstrated a 20.7% weight loss effect at a 7.2 mg dose over 72 weeks. In a past STEP-1 study of semaglutide, a dose of 2.4 mg showed 15.6% weight-loss for in-trial observation period, and 16.9% for on-treatment observation period. With an increased dose, injectable semaglutide came very close to the benchmark set by the highest dose of tirzepatide in the SURMOUNT-1 study – 22.5%.2
  • Oral Semaglutide: The OASIS 4 study showed that a 25 mg dose delivered efficacy close to that of the 50 mg dose, but with better tolerability. The estimated mean bodyweight change was –15.1% with oral semaglutide 50 mg from baseline to week 68, and –13.6% with oral semaglutide 25 mg from baseline to week 64.3
  • Tirzepatide: In the SURMOUNT-5 head-to-head study, tirzepatide demonstrated a 47% greater relative weight loss compared to Wegovy® (semaglutide). On average, tirzepatide achieved a 20.2% weight loss compared to 13.7% with Wegovy® at 72 weeks.4 In the SUMMIT study, tirzepatide reduced the risk of heart failure outcomes by 38% and significantly improved symptoms and physical limitations associated with heart failure.5 Additionally, the SYNERGY-NASH study revealed that tirzepatide was superior to placebo in resolving MASH, with over half of participants achieving improvement in fibrosis at 52 weeks.6
  • Retatrutide: Triple-hormone receptor agonist set a new benchmark in weight loss with Phase 2 data showing a 24.2% weight loss at 48 weeks (12 mg dose).7
  • Survodutide: In a Phase 2 study focused on metabolic dysfunction-associated steatohepatitis (MASH), 83% of participants treated with survodutide achieved statistically significant improvements in MASH. The drug also met all secondary endpoints, including a significant improvement in liver fibrosis.8
  • Pemvidutide: In the MOMENTUM Phase 2 study, pemvidutide demonstrated a mean weight loss of 15.6% at the highest studied dose (2.4 mg) within 48 weeks. Notably, weight loss continued in a near-linear fashion at the 2.4 mg dose by the end of treatment. In an MRI sub-study the lean loss ratio, defined as the change in lean mass compared to the change in total mass, was 21.9%. Lean mass preservation was greater in subjects aged 60 years and older, in whom the lean loss ratio was only 19.9%. In addition to lean mass preservation, there was a preferential reduction of visceral adipose tissue (VAT), the adipose tissue associated with cardiovascular risk. At the 2.4 mg dose of pemvidutide, VAT was reduced by 28.3% at Week 48 compared to a 19.5% loss in subcutaneous adipose tissue.9
  • MariTide: A Phase 2 study showed that MariTide achieved a 20% weight loss at 52 weeks with no plateau observed. Unlike other dual incretin mimetics (GLP-1/GIP agonists), MariTide acts as a GIP antagonist and offers the convenience of monthly injections.10
  • Orforglipron: A Phase 2 study demonstrated a weight loss of 14.7% at 36 weeks. Orforglipron stands out as a non-peptide-based incretin mimetic that doesn’t require special storage conditions and can be taken independently of meals, unlike oral semaglutide.11
  • VK2735: Data from Phase 1 and Phase 2 trial evaluating VK2735 (dosed subcutaneously) for metabolic disorders demonstrated encouraging safety and tolerability profile as well as positive signs of clinical benefit. Patients receiving weekly doses of VK2735 demonstrated statistically significant reductions in mean body weight after 13 weeks, ranging up to 14.7% from baseline. VK2735 is a novel dual GLP-1/GIP receptor agonist, which is being developed in both oral and injectable formulations.12
  • CagriSema: In the REDEFINE-1 Phase 3 study, CagriSema, which a combination of GLP-1-RA and amylin receptor agonist, achieved a weight loss of 22.7% over 68 weeks, matching tirzepatide’s benchmark.13
  • Amycretin: Another dual GLP-1 and amylin receptor demonstrated impressive Phase 2 results: a 22% weight reduction over just 36 weeks. This matched CagriSema’s efficacy but in half the treatment duration.14
  • CT-388: A novel dual GLP-1/GIP receptor agonist demonstrated positive results in a phase Ib study. Over 24 weeks, a once-weekly subcutaneous injection of CT-388 achieved a clinically meaningful and statistically significant mean placebo-adjusted weight loss of 18.8%. CT-388 is a weekly injectable signal-biased dual GIP/GLP-1 receptor agonist, with minimal-to-no β-arrestin recruitment on both receptors, which leads to reduced receptor internalization and potentially prolonged pharmacological activity.15
  • HRS9531: Jiangsu Hengrui Pharmaceuticals and Kailera Therapeutics reported positive topline data from a Phase 2 trial of GLP-1/GIP receptor agonist HRS9531in obesity: mean weight loss of 22.8% (21.1% placebo adjusted) at 36 weeks, and favorable safety profile with most adverse events being mild.16

Anticipated Results of Clinical Trials in 2025 and Beyond

  • Orforglipron: Insights from the ATTAIN-1 Phase 3 study (primary completion in July 2025) are highly anticipated, considering strong results of Phase 2 results: 14.7% weight loss at 36 weeks. Following this, the ATTAIN-MAINTAIN Phase 3b study (NCT06584916) will evaluate Orforglipron for sustaining weight loss in participants who completed the SURMOUNT-5 study. This trial aligns with the concept of sustainable weight reduction, investigating the effect of transitioning from weekly GLP1-RAs injectables to daily oral treatment.
  • Retatrutide: Results from the Phase 2b renal function trial (expected Q4 2025) will provide valuable insights. Additionally, the TRIUMPH-1 and TRIUMPH-2 Phase 3 master studies in obesity and type 2 diabetes have completed enrollment, with final results expected by mid-2026. In 2027, the TRIUMPH-5 study will provide a comparison of retatrutide and tirzepatide, and results on long-term outcomes from the TRIUMPH-OUTCOMES study are expected by 2029.
  • Tirzepatide: Results from the SURPASS-CVOT study (June 2025) will add light on tirzepatide by demonstrating an impact on major adverse cardiovascular events in people with type 2 diabetes. The SURMOUNT-MMO study, investigating tirzepatide’s effect on morbidity and mortality in adults with obesity, concluded enrollment in February 2024, with results expected in 2027.
  • CT-388: A Phase 2 study of CT-388has completed its recruitment. . Results are expected in Q1 2026.
  • Survodutide: Completion of the Phase 3 SYNCHRONIZE-1 study is expected in December 2025. Having achieved 19% weight loss at 48 weeks in Phase 2, will it show efficacy > 25% over a year-long maintenance therapy?
  • Pemvidutide: Results from the Phase 2b IMPACT Trial in MASH are anticipated by mid-2025. The VELOCITY Phase 3 program for obesity and type 2 diabetes is in the planning stages.

Looking Ahead: A Commitment to Innovation in Obesity Care

In December 2024, JAMA reported that for the first time in over a decade, BMI and obesity prevalence in the U.S. decreased, dropping from 46% in 2022 to 45.6% in 2023. The most notable decline occurred in the South, which had the highest per capita dispensing rate of GLP-1 receptor agonists.

As we observe World Obesity Day, these latest breakthroughs in the field of obesity management offer hope for more effective, personalized, and accessible treatments. However, sustained progress will require continued collaboration among researchers, clinicians, regulatory agencies, and industry leaders.

At Medpace, we remain committed to advancing obesity research and partnering with Sponsors to bring novel therapies to market. Our medical, operations, and regulatory staff understand the complexities of obesity trials from the perspective of the Sponsor, the clinical investigator, the scientific leader, and the reviewer at the regulatory agencies. Our matured relationships with global thought leaders, investigative sites, global ‘flagship’ metabolic site networks, and patient advocacy groups, as well as knowledge of effective patient retention strategies, ensure efficient and quality patient enrollment and retention which is key to the success of these programs.

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List of References

1. Felice Gragnano, Vincenzo De Sio, Paolo Calabrò, FLOW trial stopped early due to evidence of renal protection with semaglutide, European Heart Journal – Cardiovascular Pharmacotherapy, Volume 10, Issue 1, January 2024, Pages 7–9, https://doi.org/10.1093/ehjcvp/pvad080

2. Novo Nordisk A/S, Semaglutide 7.2 mg s.c. achieved 20.7% weight loss in the STEP UP obesity trial, and 18.7% regardless of treatment adherence, Novo Nordisk, 17 January 2025, https://www.novonordisk.com/news-and-media/news-and-ir-materials/news-details.html?id=915087

3. Efficacy and safety of oral semaglutide 25 mg in adults with . . . 23 October 2024, https://sciencehub.novonordisk.com/content/dam/sciencehub/global/en/congresses-and-scientific-publications/congresses/ow2024/Garvey/documents/Garvey_OASIS_4_OW24-oral_Final_23Oct24.pdf

4. Rodriguez PJ, Goodwin Cartwright BM, Gratzl S, et al. Semaglutide vs Tirzepatide for Weight Loss in Adults With Overweight or Obesity. JAMA Intern Med. 2024;184(9):1056–1064. doi:10.1001/jamainternmed.2024.2525

5. Lilly’s tirzepatide successful in phase 3 study showing benefit in adults with heart failure with preserved ejection fraction and obesity | Eli Lilly and Company, 1 August 2024, Eli Lilly and Company. https://investor.lilly.com/news-releases/news-release-details/lillys-tirzepatide-successful-phase-3-study-showing-benefit

6. Lilly’s tirzepatide was superior to placebo for MASH resolution, and more than half of patients achieved improvement in fibrosis at 52 weeks | Eli Lilly and Company, 8 June 2024, Eli Lilly and Company. https://investor.lilly.com/news-releases/news-release-details/lillys-tirzepatide-was-superior-placebo-mash-resolution-and-more

7. Lilly’s phase 2 retatrutide results published in The New England Journal of Medicine show the investigational molecule achieved up to 17.5% mean weight reduction at 24 weeks in adults with obesity and overweight | Eli Lilly and Company, 26 June, 2023, Eli Lilly and Company. https://investor.lilly.com/news-releases/news-release-details/lillys-phase-2-retatrutide-results-published-new-england-journal

8. Survodutide Phase II Trial Shows 83% of Adults Treated Achieved Groundbreaking Results in Liver Disease due to MASH, with Significant Improvements in Fibrosis. Boehringer-Ingelheim.com, 26 February 2024, www.boehringer-ingelheim.com/human-health/metabolic-diseases/survodutide-top-line-results-mash-fibrosis

9. CORRECTION – Altimmune presents results of a Phase 2 MRI-Based Body Composition Sub-Study at 60th Annual Meeting of the European Association for the Study of Diabetes – Altimmune, 10 September 2024, Altimmune. https://ir.altimmune.com/news-releases/news-release-details/correction-altimmune-presents-results-phase-2-mri-based-body

10. MariTide Update, Amgen, 26 November 2024, https://investors.amgen.com/static-files/0176d78e-920b-45b3-b9cc-a727e58e80da

11. Lilly’s phase 2 results published in the New England Journal of Medicine show orforglipron, a once-daily oral nonpeptide GLP-1 receptor agonist, achieved up to 14.7% mean weight reduction at 36 weeks in adults with obesity or overweight | Eli Lilly and Company, 23 June 2023, Eli Lilly and Company. https://investor.lilly.com/news-releases/news-release-details/lillys-phase-2-results-published-new-england-journal-medicine

12. Viking Therapeutics Reports New Data from VK2735 Obesity Program at ObesityWeek® 2024, 4 November 2024, Viking Therapeutics InvestorRoom. https://ir.vikingtherapeutics.com/2024-11-04-Viking-Therapeutics-Reports-New-Data-from-VK2735-Obesity-Program-at-ObesityWeek-R-2024

13. Novo Nordisk A/S: CagriSema demonstrates superior weight loss in adults with obesity or overweight in the REDEFINE 1 trial, 20 December 2024, Novo Nordisk. https://www.novonordisk.com/news-and-media/news-and-ir-materials/news-details.html?id=915082

14. Novo Nordisk successfully completes phase 1b/2a trial with subcutaneous amycretin in people with overweight or obesity, 24 January 2025, Novo Nordisk. https://www.novonordisk.com/news-and-media/news-and-ir-materials/news-details.html?id=915251

15. Chakravarthy, M. V., Argüelles-Tello, F. A., Sanchez-Sanchez, L. L., Ortiz, W. G., Elliott, M., Wu, J., Acosta, L., Rankin, J. E., & Steinberg, A, 12 September 2024, Safety, pharmacokinetics, and pharmacodynamics of CT-388, a signal-biased dual GLP-1/GIP receptor agonist, over 24 weeks in adults with obesity. https://medically.roche.com/global/en/medical-material.3d8d7ba5-5a5d-4b7d-bed7-f4f5e05e5a6e.qr.html?cid

16. Kailera, 12 January 2025, Jiangsu Hengrui Pharmaceuticals and Kailera Therapeutics Report Positive Topline Data from 8 mg Dose of Phase 2 Obesity Trial of GLP-1/GIP Receptor Dual Agonist HRS9531 – Kailera. https://www.kailera.com/press-release/jiangsu-hengrui-pharmaceuticals-and-kailera-therapeutics-report-positive-topline-data-from-8-mg-dose-of-phase-2-obesity-trial-of-glp-1-gip-receptor-dual-agonist-hrs9531/

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