Study Finds Lilly’s Tirzepatide Reduces A1C and Body Weight


Editor’s Note: This article was updated on 5/20/21 and adds to our ongoing coverage of Tirzepatide, a potential new treatment for people with Type 2 diabetes that is currently in development in clinical trials. 

Lilly Diabetes reported that in the 52-week SURPASS-4 clinical trials, the largest and longest of the programs to date, the highest dose of tirzepatide (15 mg) led to significant A1C and bodyweight reduction in adults with Type 2 diabetes. With the highest dose of tirzepatide, 91 percent of participants achieved an A1C that was less than seven percent.

SURPASS-4 isn’t the only clinical trial that’s shown positive results. The other clinical trial, SURPASS-3, a 52-week study, also showed the highest dose of tirzepatide (15 mg) reduced A1C 2.37 percent and body weight by 12.9 kg/28.4 lbs. In SURPASS-3, participants who received the highest dose and on average, have had diabetes for a little over 13 years, achieved an A1C of less than 5.7 percent — the level seen in people without diabetes.

In both studies, the overall safety profile is similar to that of a glucagon-like peptide (GLP-1 1) receptor agonist. Side effects were reported, with gastrointestinal side effects being the most commonly reported.

John Doupis, MD, PhD, director of the diabetes division and clinical research center at the Latriko Paleou Falirou Medical Center, provided remarks on the latest findings and acknowledged the importance of tirzepatide’s impact on managing Type 2 diabetes. “Tirzepatide delivered impressive results in this study, providing superior A1c reductions compared to insulin glargine–as well as the addition of significant weight loss–in people with Type 2 diabetes who have increased cardiovascular risk,” Doupis said in a news release.

Tirzepatide “is a once-weekly dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist that integrates the actions of both incretins into a single novel molecule.” In other words, tirzepatide works by decreasing food intake and increasing energy output which works in tandem to generate weight loss and regulate blood glucose levels. This also marks the first-ever dual GIP-GLP combo drug used for Type 2 treatment.

These new findings are similar to the results published in February when Lilly Diabetes reported tirzepatide significantly reduced A1C and body weight in adults with Type 2 diabetes. Participants who used the highest dose of tirzepatide reduced A1Cs by 2.37% and body weight by 12.9%; about 50% of patients in this study achieved an A1C of less than 5.7%.

The study observed that each of the tirzepatide doses led to lower A1Cs and reducded body weight. Lilly reported the following:

  • A1C reduction: -2.11% (5 mg), -2.30% (10 mg), -2.41% (15 mg), -1.39% (placebo)
  • Weight reduction: -6.4 kg (5 mg), -8.9 kg (10 mg), -10.6 kg (15 mg), +1.7 kg (placebo)
  • Percentage of participants achieving A1C <7%: 75.1% (5 mg), 82.9% (10 mg), 84.9% (15 mg), 48.8% (placebo)

The safety of tirzepatide was consistent with the glucagon-like peptide-1 (GLP-1). Side effects were reported with gastrointestinal being the most commonly reported.

Currently, tirzepatide is in its fifth and final study for blood glucose management in adults with Type 2 diabetes. SURPASS-4 included 2,002 study participants from the United States, Canada, Brazil, Australia, and Israel; patients were either given 5 mg, 10 mg, or 15mg of tirzepatide or a placebo (no treatment) in a 1:1:1:3 ratio during a 52-week period. This was done in order to demonstrate that using tirzepatide, especially higher doses of the medication, resulted in a greater outcome for A1C and body weight reductions opposed to no treatment.

“These strong results reinforce our belief that tirzepatide has the potential to be an exciting treatment for people living with Type 2 diabetes,” said Mike Mason, president of Lilly Diabetes in a press release. “We look forward to meeting our goal of bringing an important new therapy to people living with this condition, including sharing more detailed results at scientific congresses and submitting to regulatory authorities later this year.”

Further data about the SURPASS clinical trial will be presented at the 57th Annual Meeting of the European Association for the Study of Diabetes.


WRITTEN BY Makaila Heifner, POSTED 01/08/21, UPDATED 05/20/21

Makaila was diagnosed with Type 1 diabetes at 16 months old. Before joining the Beyond Type 1 team in 2019, she worked at several diabetes camps, including Camp Leo and DYF. Makaila earned her BA in Global Studies and a minor in Public Policy from the University of California, Berkeley. When she isn’t editing articles, Makaila is a fan of soup, public radio, and live music. Check her out on Instagram: @makailaheifner