GLP‑1 news from 2021
21 dated, sourced GLP-1 developments from 2021: approvals, trial results, prices, lawsuits, compounding and culture.
- Business
Novo Nordisk to buy Dicerna Pharmaceuticals for $3.3 billion
Novo Nordisk agreed on Nov. 18, 2021, to acquire Dicerna Pharmaceuticals for $3.3 billion, or $38.25 a share, the Danish drugmaker's largest acquisition to that point. Dicerna is a specialist in RNA interference, a line of drug research separate from the GLP-1 medicines Novo Nordisk is best known for.
- Business
Wegovy supply problems that began in 2021 grew into a shortage FDA resolved in 2025
Supply problems that started within months of Wegovy's June 2021 approval grew into a shortage that FDA declared resolved on February 21, 2025. Wegovy had been on the shortage list since March 31, 2022 and Ozempic since August 23, 2022. The order gives compounders until April 22, 2025 under section 503A and May 22, 2025 under section 503B before that enforcement discretion ends.
- Regulation
Lilly filed Mounjaro application for type 2 diabetes in September 2021
Eli Lilly submitted new drug application 215866 for Mounjaro (tirzepatide) injection on September 14, 2021, and the FDA recorded receiving it on September 15, 2021. The application sought approval for adults with type 2 diabetes, and the FDA approved it; the approval letter is signed May 13, 2022 and sets a 24-month shelf life plus required pediatric, lactation and thyroid cancer studies.
- Research and trials
Obesity Society review finds only 16 of 315 supplement trials showed weight loss
A systematic review published in the journal Obesity examined 315 randomized controlled trials of dietary supplements and alternative therapies for weight loss. Only 52 of the trials were rated low risk of bias and adequate to support efficacy, and just 16 of those showed a significant weight difference from placebo, ranging from 0.3 to 4.93 kilograms. A perspective published alongside the review by The Obesity Society's Clinical Committee advised clinicians to weigh the thin evidence for these products and guide patients toward approaches that have been tested.
- Research and trials
Semaglutide 2.0 mg lowers blood sugar more than 1.0 mg in 40-week trial
In the SUSTAIN FORTE trial, weekly semaglutide 2.0 mg lowered HbA1c by an average of 2.2 percentage points over 40 weeks in adults with inadequately controlled type 2 diabetes, compared with 1.9 points for the 1.0 mg dose. Average weight loss was 6.9 kg versus 6.0 kg. Gastrointestinal side effects were reported by 34% of the higher-dose group and 31% of the lower-dose group, and serious adverse events were similar. Novo Nordisk funded the trial.
- Research and trials
Tirzepatide lowers A1c and weight more than semaglutide 1 mg in head-to-head trial
In a 40-week phase 3 trial, 1,879 adults with type 2 diabetes taking metformin were randomly assigned to tirzepatide 5 mg, 10 mg, or 15 mg, or semaglutide 1 mg, all once weekly. A1c fell by 2.01 to 2.30 percentage points with tirzepatide versus 1.86 points with semaglutide, and weight reductions were 1.9 kg to 5.5 kg greater with tirzepatide. The trial reported tirzepatide as noninferior and superior to semaglutide at all three doses.
- Research and trials
Tirzepatide cuts A1c by up to 2.07 points in phase 3 type 2 diabetes trial
In the 40-week SURPASS-1 trial, once-weekly tirzepatide lowered A1c by 1.87 to 2.07 percentage points in 478 adults with type 2 diabetes not controlled by diet and exercise alone, compared with a 0.04-point rise on placebo. Between 31% and 52% of participants on tirzepatide reached an A1c below 5.7%, versus 1% on placebo, and weight fell 7.0 to 9.5 kg. The most common side effects were mild to moderate gastrointestinal symptoms.
- Regulation
FDA approves Wegovy for weight management in obesity
On June 4, 2021, the FDA cleared Wegovy (semaglutide) injection for chronic weight management in adults with obesity, or in adults who are overweight with at least one related health condition. Novo Nordisk's product was the first semaglutide version carrying a weight-loss claim, after Ozempic in 2017 and Rybelsus in 2019 were approved for type 2 diabetes. Federal records list the decision under application 215256 with priority review.
- Prices
Wegovy launched in 2021 with a list price above $1,300 a month
Novo Nordisk brought Wegovy to the U.S. market in June 2021 at a list price above $1,300 a month, when insurance coverage for obesity medicines was uncommon. The list price stayed in that range for years before the company announced a significant reduction in February 2026, and self-pay prices now range from $149 to $399 a month depending on dose and formulation.
- Science
Study in obese mice ties tirzepatide's GIP receptor to insulin sensitivity without weight loss
A study published May 18, 2021, in the Journal of Clinical Investigation reports that tirzepatide raised the glucose infusion rate 1.7-fold in obese mice that were bred to lack the GLP-1 receptor and that lost no weight. The researchers traced the insulin-sensitizing effect to glucose disposal into white adipose tissue and attributed it to GIP receptor agonism.
- Culture
Exercise plus liraglutide beat either alone for fat loss in one-year trial
A randomized trial published in the New England Journal of Medicine found that adults with obesity who combined a structured exercise program with the GLP-1 drug liraglutide for one year lost more weight and body fat than those using either approach alone. The combination group lost 9.5 kg more than placebo, compared with 4.1 kg for exercise alone and 6.8 kg for liraglutide alone. Body-fat percentage fell 3.9 percentage points with the combination, roughly twice the reduction seen with either single treatment.
- Science
Mouse study links brain GIP receptors to dual GLP-1/GIP agonist advantage
A study published April 6, 2021, in Cell Metabolism reports that mice lacking GIP receptors in the central nervous system are protected from diet-induced obesity, and that a dual GLP-1/GIP agonist loses its superiority over a GLP-1-only agonist in those animals. The findings point to the brain as a key site for GIP's effects on body weight and food intake. Human data have not been reported.
- Research and trials
STEP 4 trial finds stopping weekly semaglutide leads to weight regain
In the STEP 4 trial published in JAMA, 803 adults with overweight or obesity who had already lost an average of 10.6% of their body weight on weekly semaglutide 2.4 mg were randomly assigned to keep taking the drug or switch to placebo. Over the next 48 weeks, those who continued lost another 7.9% of body weight while those on placebo gained 6.9% — a difference of 14.8 percentage points. Waist circumference, systolic blood pressure and physical functioning also moved in favor of continued treatment.
- Research and trials
Novo Nordisk reports 68-week weight loss data for semaglutide 2.4 mg
On March 23, 2021, Novo Nordisk reported that adults with obesity treated with semaglutide 2.4 mg achieved and maintained a significant amount of weight loss over a 68-week trial. The announcement did not include an average weight-loss percentage, the number of participants or the name of the trial. The FDA approved semaglutide for weight management under the brand name Wegovy on June 4, 2021.
- Research and trials
Semaglutide 2.4 mg produced 14.9% average weight loss in 68-week trial
In a 68-week trial, 1,961 adults with overweight or obesity but without diabetes lost an average of 14.9% of their body weight on weekly semaglutide 2.4 mg, compared with 2.4% on placebo, a difference of 12.4 percentage points. In the semaglutide group, 86.4% lost at least 5% of body weight, 69.1% lost at least 10% and 50.5% lost at least 15%.
- Research and trials
Semaglutide 2.4 mg cut weight 9.6% in adults with type 2 diabetes in STEP 2 trial
In the phase 3 STEP 2 trial, 1,210 adults with overweight or obesity and type 2 diabetes were assigned to weekly semaglutide 2.4 mg, semaglutide 1.0 mg or placebo for 68 weeks. Those on 2.4 mg lost an estimated 9.6 percent of body weight, versus 3.4 percent on placebo. Gastrointestinal side effects were more common with semaglutide than with placebo.
- Research and trials
Weekly semaglutide plus intensive counseling produced 16% average weight loss in STEP 3 trial
In the STEP 3 trial, 611 adults with overweight or obesity but without diabetes were assigned to weekly semaglutide 2.4 mg or placebo, both combined with intensive behavioral therapy and an initial low-calorie diet. Average weight loss over 68 weeks was 16.0% with semaglutide versus 5.7% with placebo, and 55.8% of semaglutide participants lost at least 15% of their body weight versus 13.2% on placebo. Gastrointestinal side effects were more frequent with semaglutide, and 3.4% of that group stopped treatment because of them.
- Research and trials
STEP 1 trial reports 14.9% average weight loss with semaglutide 2.4 mg
The New England Journal of Medicine published the STEP 1 trial on Feb. 10, 2021. Adults with overweight or obesity who took once-weekly semaglutide 2.4 mg plus lifestyle intervention lost an average of 14.9% of body weight over 68 weeks, versus 2.4% on placebo, and 50.5% lost at least 15%. About 4.5% of participants on the drug stopped treatment because of gastrointestinal side effects.
- Business
Higher-dose Trulicity lowers A1C and weight modestly in AWARD-11 trial
In the AWARD-11 trial of 1,842 people with type 2 diabetes, weekly dulaglutide (Trulicity) 4.5 mg lowered A1C by 1.77 percentage points at 36 weeks versus 1.54 points for the 1.5 mg dose. The 4.5 mg dose also produced 1.6 kg more weight loss than 1.5 mg, with slightly more nausea and vomiting at the higher doses.
- Science
Semaglutide 2.4 mg cut food intake 35% in 20-week obesity trial
In a 20-week trial of 72 adults with obesity, once-weekly semaglutide 2.4 mg reduced energy intake at a free-access lunch by 35% compared with placebo (1736 versus 2676 kilojoules) and lowered reported hunger and food cravings. The study found no evidence that the drug slowed gastric emptying at week 20, pointing to appetite control in the brain as the main driver. Body weight fell 9.9% with semaglutide versus 0.4% with placebo.