Eli Lilly and Company says the highest doses of its next-generation weight loss drug helped patients lose an average of 28.7 percent of their body weight in a new study, significantly more than its popular Zepbound drug currently on the market.

The drugmaker released results of its successful Phase 3 trial on Thursday, reporting that patients with obesity lost an average of 71.2 pounds in 68 weeks using 12-mg doses of retatrutide. Lilly describes it as a first-in-class drug that targets three appetite-regulating hormones: GIP, GLP-1, and glucagon. Current weight loss drugs only target one or two of those appetite-regulating hormones.

The drug also helps significantly reduce pain associated with knee osteoarthritis, a condition linked to obesity.

Nearly 40 percent of the patients receiving the highest doses lost more than 30 percent of their body weight and around a quarter of study participants on that dose lost more than 35 percent of their body weight.

Patients taking a lower 9 mg dose of the drug lost an average of 26.4 percent of their body weight, with nearly half of participants losing more than a quarter of their weight.

The most common side effects reported by patients were nausea, diarrhea, and constipation — similar to complaints from patients on current GLP-1 weight loss drugs.

Lilly reported that some patients in the study, called TRIUMPH-4, dropped out early because they had lost so much weight that they perceived it as excessive.

The company will continue late-stage trials of the once-weekly treatment for obesity and type 2 diabetes next year in an effort to get the drug approved for sale. Lilly says it will also test a lower maintenance 4 mg dose. A timeline for final approval was unclear.

“We are encouraged by the results of TRIUMPH-4, which highlight the powerful effect of retatrutide, a first-in-class triple agonist, on body weight, pain, and physical function,” the president of Lilly Cardiometabolic Health, Kenneth Custer, said in a statement. “With seven additional Phase 3 readouts expected in 2026, we believe retatrutide could become an important option for patients with significant weight loss needs and certain complications, including knee osteoarthritis.”

About one in eight adults say they are currently taking a GLP-1 drug to lose weight or treat a chronic condition, according to a KFF Health Tracking Poll. BMO Capital markets has predicted the global market for the growing and lucrative weight-loss drugs will reach $100 billion by 2035.

Lilly has overtaken rival Novo Nordisk — the maker of Wegovy and Ozempic — to dominate sales. Zepbound jumped in popularity after clinical trials showed it was more effective than Wegovy and had fewer complaints about side effects.

Both companies have been lowering prices of their weight loss drugs for self-pay customers. Many insurance companies have balked at covering the drugs because of their high prices while the drugs were too expensive for many patients to pay out-of-pocket — especially on a long-term basis.

The drug makers are now selling the drugs directly to consumers through their websites with starting doses as low as $199 a month and higher doses for under $450 a month. That compares to list prices north of $1,000 a month.

The Trump administration recently negotiated with the drug companies to lower what they charge Medicaid programs for weight loss drugs. Under the agreement, Medicare enrollees will have access to them sometime next year with a $50 copay.