On the 23rd (local time), the American Diabetes Association Annual Scientific Sessions (ADA 2025) kicked off in Chicago, where global pharmaceutical companies such as Eli Lilly and Co., Amgen Inc., and Denmark's Novo Nordisk presented major clinical trial data for diabetes and obesity treatment candidates. Stock prices are fluctuating as these companies experience mixed fortunes in their clinical trials for obesity treatment.
Eli Lilly has succeeded in confirming the blood sugar improvement and weight loss effects of an oral obesity treatment, predicting significant changes in the existing injection-centered obesity and diabetes treatment market. In contrast, Novo Nordisk's developing obesity drug received evaluations suggesting that it did not meet market expectations despite showing positive effects. Amgen's drug also exhibited side effects such as vomiting in its clinical trials.
◇Lilly's oral obesity drug emerges as a game changer
Eli Lilly reported that its clinical phase 3 trial of 'Orforglipron', an oral glucagon-like peptide (GLP)-1 mimetic taken once a day, showed an average weight reduction of 7.9% (7.25 kg) over 40 weeks. GLP-1 promotes the secretion of insulin, which is a postprandial blood sugar control hormone, while suppressing the secretion of glucagon, which raises blood sugar.
Orforglipron is a medication taken once a day, regardless of meals, and has drawn attention as an alternative to existing injectable obesity treatments. Originally developed by Japan's Chugai Pharmaceutical, Eli Lilly secured global rights in 2018 and has been developing it. This clinical trial was conducted on 559 adult patients with type 2 diabetes across five countries, including the United States, China, India, Japan, and Mexico.
The clinical trial confirmed improvements in blood sugar levels as well as weight loss. Participants showed a reduction in glycated hemoglobin levels by 1.3% to 1.6%, and about 65% brought their blood sugar levels back to normal ranges. Glycated hemoglobin is an indicator that shows the average blood sugar over the past 2 to 3 months. A glycated hemoglobin level above 6.5% indicates a diabetes diagnosis. Reported drug side effects included diarrhea, nausea, digestive disorders, and constipation, which were assessed to be similar to existing injectable GLP-1 treatments.
However, in this clinical trial, Orforglipron's weight reduction effect was found to be lower than that of existing obesity treatment injections like Wegovy and Zepbound. In clinical trials conducted over 52 to 72 weeks, Zepbound and Wegovy showed weight loss effects ranging from 15% to 20% or more, depending on the dosage. Nevertheless, Orforglipron received positive evaluations in the market for confirming safety and efficacy as an oral treatment. On that day, Eli Lilly's stock price closed up 1.51% compared to the previous day's closing.
Eli Lilly stated, "Orforglipron is effective enough to replace injections," adding that "it could significantly enhance patient adherence and treatment accessibility." Existing GLP-1 injectables are protein-based (peptide) and require refrigeration, making them more difficult to manufacture. Orforglipron, however, consists of small, stable non-peptide chemical substances that can be stored at room temperature and are easier to produce.
The company plans to submit Orforglipron for obesity treatment to the U.S. Food and Drug Administration (FDA) by the end of this year, with plans to expand its indications to diabetes by 2026.
◇Novo's stock falls despite successful clinical trial announcement
Novo Nordisk announced at this year's ADA 2025 that CagriSema, a follow-up drug to its GLP-1 obesity treatment Wegovy, showed an average weight loss of 20.4% over 68 weeks in its phase 3 clinical trial. The placebo group achieved only around 3% weight reduction.
CagriSema is a combination of 2.4 mg semaglutide, the active ingredient in Wegovy, and 2.4 mg of the long-acting amylin analogue, cagrilintide, administered through subcutaneous injection once a week. Cagrilintide is a drug that mimics amylin, a hormone released from the pancreas along with insulin, controlling appetite and enhancing satiety.
This clinical trial was conducted on 641 adults with obesity or overweight without type 2 diabetes, and the participants received subcutaneous injections once a week for 68 weeks. The results showed that patients with high treatment adherence lost an average of 22.7% of their weight over 68 weeks. 23.1% of participants lost more than 30% of their weight. Half (50.7%) of the participants had a body mass index (BMI) drop below 30.
The most commonly reported side effects included nausea, constipation, and vomiting, most of which were transient and mild to moderate in severity. The rate of treatment discontinuation due to adverse reactions was 6% for the CagriSema group and 3.7% for the placebo group, indicating good safety.
Novo Nordisk noted, "CagriSema demonstrates superior weight reduction effects compared to single agents, potentially setting a new standard in obesity treatment," and stated that it would explore CagriSema's various possibilities through clinical trials. The company is currently conducting follow-up clinical trials for CagriSema to obtain FDA approval, aiming for commercial launch in 2026.
Despite the successful clinical trial results, Novo Nordisk's stock price fell on the New York Stock Exchange. It is interpreted that this clinical data, which was lower than the projected '25% weight loss' forecasted during last month’s investor briefing, led to negative sentiment in the market. The company's stock price dropped from $81.05 at the close on the 12th to $70.10 on the 23rd.
◇Amgen highlights side effects of monthly injection
Amgen presented results from its phase 2 trial of MariTide, a long-acting injectable drug administered once a month, at the ADA this year. MariTide targets two pathways involved in blood sugar control and metabolism and is a candidate for obesity treatment administered once a month.
The company stated that it confirmed an average weight loss effect of 16.2% over 52 weeks in this phase 2 trial conducted on adult obesity patients. In the group of patients with diabetes, weight loss effects of 12.3% to 17% were confirmed.
However, gastrointestinal side effects such as vomiting and nausea were reported, resulting in a high dropout rate among clinical trial participants. Amgen announced plans to shift its dosage strategy in phase 3 by gradually increasing the dosage over 8 weeks. In this phase 2 trial, patients who rapidly increased their medication had a dropout rate of 50%, while the dropout rate for those who gradually increased their dosage was 22%.
As a result of this announcement, Amgen's stock price closed down 5.31% on the New York Stock Exchange compared to the previous day. Amgen stated, "The weight loss effects were comparable to existing GLP-1 treatments or better in some measures," adding, "We will optimize clinical design to increase sustainability of the treatment and enhance the feasibility of commercialization.”