The news: Eli Lilly’s next-generation weight loss drug delivered significant weight reductions, outperforming its currently approved Zepbound, according to new study data.

• Patients who stayed on the highest dose of the experimental drug, called retratrutide, lost an average 71.2 pounds, or 28.7% of their body weight, after 68 weeks. Zepbound weight loss averages around 21%, for comparison.
• Retratrutide is a first-in-class “triple-G” drug targeting GLP-1, GIP, and glucagon hormones. Zepbound targets two of those (GLP-1 and GIP).
• The study involved overweight or obese patients with knee osteoarthritis. Results from 7 additional retratrutide trials are due next year.

Why it matters: While Lilly’s new data shows the strongest weight loss results in a drug study so far, many patients stopped treatment over concerns and pronounced side effects.

• Lilly’s stock price rose 3.4% after the study data was released, underscoring its recent milestone as the first $1 trillion dollar healthcare company.
• However, it’s worth noting that 12.1% of patients stopped taking the drug because of adverse events, which included “perceived excessive weight loss,” per Lilly.
• Side effects were common, with nausea rates up to 43%, diarrhea 33%, and vomiting around 21% across the study.
• For context, in Zepbound trials, 5% to 7% of patients dropped out due to side effects, while patients on the highest dose experienced a nausea rate of 28%, diarrhea at 25%, and vomiting at 13%, per its FDA prescribing information.

Implications for pharma: Lilly’s results signal a new phase for obesity drugs where weight loss can reach up to 30%, but side effects and clinical risks rose alongside the results.

If treatments can cause excessive weight loss, pharma companies need to consider how they screen, inform, and monitor patients. Marketing will need to shift from highlighting efficacy numbers to delivering tailored patient guidance, clear risk communications, and stronger support tools. As people clamor for better results, it will be up to doctors and marketers to ensure safe and responsible use.