SURMOUNT-5’s results reflect those of multiple real-world studies, which have found that tirzepatide treatment results in stronger weight loss than semaglutide.
Eli Lilly on Wednesday released data from the Phase IIIb SURMOUNT-5 study, demonstrating that Zepbound (tirzepatide) can elicit greater weight loss than its top competitor, Novo Nordisk’s Wegovy (semaglutide).
At 72 weeks, patients taking Zepbound lost 22.8 kg (50.3 lbs), versus 15.0 kg (33.1 lbs) for those in the Wegovy group. Lilly’s obesity drug led to a 47% greater relative weight loss versus Wegovy, according to the Indiana-based pharma, which noted that Zepbound reduced participants’ weight by 20.2% on average, as compared with 13.7% in Wegovy comparators.
Zepbound likewise emerged victorious in the secondary endpoint analysis of the percentage of patients achieving a specific level of weight loss, with 31.6% of treated patients losing at least 25% of their body weight, versus 16.1% in the Wegovy group.
Leonard Glass, senior vice president of global medical affairs at Lilly Cardiometabolic Health, in a statement said the pharma is “thrilled” by the findings of SURMOUNT-5, which will help patients and their healthcare providers “make informed decisions about treatment choice.”
“Zepbound is in a class of its own as the only FDA-approved dual GIP and GLP-1 receptor agonist obesity medication,” Glass added.
Truist Securities’ analyst Srikripa Devarakonda in a Wednesday investor note wrote that SURMOUNT-5’s readout “underscores [tirzepatide’s] competitiveness vs [semaglutide],” however adding that the data would only boost Lilly’s shares “marginally.” This lukewarm reception, according to Devarakonda, would be likely because Wegovy’s weight-loss results in the study were “in-line with investor expectations and confirmed prior cross-trial comparisons.”
Instead, Devarakonda anticipates upcoming catalysts in the weight-loss space, namely the readout of Novo Nordisk’s CagriSema—expected in the fourth quarter—and the FDA’s final decision on tirzepatide’s shortage status.
Similarly, BMO Capital Markets’ Evan David Seigerman wrote in a note that Wednesday’s results “come as expected for most, formalizing what in our view was already consensus knowledge.”
“Following today’s head-to-head trial, SURMOUNT-5 could provide Lilly the opportunity to claim superior advantage over Novo’s semaglutide in its labeling when speaking about efficacy. This advantage could provide incremental upside to tirzepatide sales, but does not necessarily represent a new understanding of the drug’s profile,” he added.
Wednesday’s data drop echoes previous studies, which have shown a stronger efficacy profile for tirzepatide than semaglutide. In July 2024, for instance, a cohort study published in JAMA Internal Medicine showed that patients treated with Lilly’s weight-loss therapy were significantly more likely to achieve weight loss.
Reductions in body weight were likewise greater for patients on tirzepatide, reaching a nearly 7% advantage at 12 months, the study found.
Meanwhile, in November 2023 analytics firm Truveta Research put out a comparative analysis of electronic health records, finding more rapid weight loss with Lilly’s diabetes drug Mounjaro (tirzepatide) versus Novo’s competitor Ozempic (semaglutide). At three months, patients on Mounjaro lost 5.9% of body fat compared with 3.6% in those on Novo’s drug. At 1 year, mean weight reduction in the Mounjaro arm jumped to 15.2%, while that in the Ozempic group increased to 7.9%.
SURMOUNT-5 could help Lilly gain ground on Novo, which has maintained a tenuous lead in the obesity space, driven primarily by its first-to-market advantage for Ozempic, which was approved in 2017. Mounjaro won the FDA’s greenlight in 2022. In the third quarter, Novo beat the consensus estimates for Ozempic and Wegovy sales, while Lilly’s Mounjaro and Zepbound disappointed analysts.
