Lilly Reports Phase 3 Retatrutide Results Against Semaglutide in Type 2 Diabetes

Eli Lilly announced positive topline results on October 28 from a Phase 3 trial comparing its investigational medicine retatrutide with injectable semaglutide 2 mg in adults with type 2 diabetes. The company reported greater average weight reduction with both retatrutide doses and a larger A1c reduction than the comparator. The findings remain a sponsor announcement: detailed results have not yet appeared in a peer-reviewed publication.

The study, called TRANSCEND-T2D-2, randomized 1,298 adults whose type 2 diabetes was not adequately controlled with metformin, with or without an SGLT2 inhibitor. Participants received weekly retatrutide at 9 mg or 12 mg, or weekly semaglutide 2 mg, for 80 weeks. The trial was open-label, meaning participants and study teams knew which treatment was given. At entry, participants’ mean A1c was 8.3%; their mean weight was 102.4 kilograms and mean body-mass index was 36.8.

Reported glucose and weight outcomes

Lilly reported that mean A1c fell by 2.2 percentage points in each retatrutide group and by 1.8 points with semaglutide. The company said the 12 mg dose met the trial’s statistical test for superiority on the key secondary A1c outcome; the 9 mg result was not reported as statistically superior on that measure. Both doses met the primary non-inferiority objective.

For body weight at week 80, the company reported average reductions of 19.5% (44.3 pounds) with 9 mg retatrutide and 20.9% (47.4 pounds) with 12 mg, compared with 9.4% (20.9 pounds) with semaglutide 2 mg. Lilly reported that both weight comparisons met its statistical test for superiority. These are trial averages, not a prediction for any individual, and the comparison is specifically against the 2 mg injectable semaglutide dose used in this study.

Adverse events and tolerability

Gastrointestinal events—including diarrhea, nausea, constipation, vomiting and indigestion—were among the most commonly reported adverse events. The company said most were mild or moderate and generally resolved during treatment. It reported discontinuation because of adverse events in 4.8% of participants receiving 9 mg retatrutide, 7.9% receiving 12 mg, and 2.7% receiving semaglutide. Lilly also reported dysesthesia, an abnormal skin sensation, in 4.8%, 6.5% and 2.7% of the respective groups. A complete assessment will require the full safety tables and methods, not only topline figures.

What the announcement does—and does not—show

Retatrutide acts on multiple hormone receptors and remains investigational. Lilly states that it has not been approved by the U.S. Food and Drug Administration or any other regulatory organization and cannot be legally sold or marketed for human use. The existence of a registered clinical trial in Canada is not marketing authorization. These results therefore do not establish retatrutide as an available treatment or support replacing a patient’s current therapy.

Interpretation is also limited by the open-label design and the fact that the announcement contains topline rather than a complete, independently reviewable dataset. The sponsor says detailed results will be presented at a future scientific meeting and submitted for publication. Those materials will be needed to assess the analysis plan, missing data, participant characteristics, full adverse-event profile and how the results compare with other treatment options. This trial should not be generalized to every GLP-1 medicine, dose, patient group or clinical setting.

Practical context for pharmacy teams

For now, the main practice point is to distinguish research news from an approved treatment option. Patients may encounter social-media posts or websites offering products under the retatrutide name. Pharmacists can explain that this trial evaluated a study medicine under a research protocol, while commercially marketed products claiming to be retatrutide are not approved medicines. Questions about an individual’s diabetes treatment should be addressed with their prescriber and pharmacist using currently authorized options and the patient’s clinical circumstances.