In this test of its effectiveness as a diet aid, people taking Victoza for over a year lost an average of 8 percent of their body weight, compared with 2.6 percent shed by those taking a placebo (dummy drug), researchers found.
"Liraglutide, an injection treatment already approved for diabetes treatment, can help reduce body weight in people with obesity when used at a higher dose than is usually used in diabetes," said lead researcher Dr. John Wilding, head of the department of obesity and endocrinology at the University of Liverpool in England.
"These results suggest liraglutide is effective and overall well-tolerated for obesity treatment," he said.
Although this study didn't compare Victoza with other weight loss drugs, Wilding said that a previous study showed Victoza could produce about twice as much weight loss as another drug, orlistat (Xenical).
Xenical works by reducing the amount of fat the intestines can absorb. People taking Xenical lose an average of five to seven pounds, studies have shown.
Victoza works by lowering blood sugar.
The results of the study were scheduled for presentation Thursday at the European Congress on Obesity in Sofia, Bulgaria. Data and conclusions presented at meetings are usually considered preliminary until published in a peer-reviewed medical journal.
Dr. David Katz, director of the Yale University Prevention Research Center in New Haven, Conn., wasn't surprised by the findings. "A number of drugs used to treat type 2 diabetes tend to produce weight loss as one of their effects," said Katz, who was not involved in the study.
This is predictable because the insulin resistance that precedes and often accompanies type 2 diabetes results in frequent hunger and weight gain. Lowering blood sugar results in weight loss, he said.
Whether Victoza improves long-term weight management or leads to better health outcomes over years when used for weight loss is unknown, he said.
"But for now, Victoza takes its place alongside other drugs studied initially for diabetes, but [found to be] potentially useful for weight loss as well," Katz said.
"Such drugs will never replace diet and physical activity, but may prove a reasonable addition to lifestyle intervention in some patients," Katz added.
For the study, Wilding and colleagues randomly selected 3,731 obese and overweight adults to take daily injections of Victoza or a placebo. The participants' average age was 45.
People in both groups also followed a diet containing 500 fewer calories than a normal diet. And they had to increase physical activity by walking briskly for 30 minutes at least five times a week.
Many participants (61 percent) had blood sugar levels that made them prediabetics, but none had full-blown type 2 diabetes, the researchers note.
The researchers found that almost two-thirds of those taking Victoza lost 5 percent or more of their body weight, and one-third lost 10 percent or more. Among those taking the placebo, 27 percent lost 5 percent of their body weight or more, and one in 10 lost 10 percent or more.
People taking Victoza also saw a drop in their blood sugar, blood pressure and cholesterol, the study found.
Based on these phase 3 trial findings, drug maker Novo Nordisk is asking the U.S. Food and Drug Administration to approve Victoza for weight loss. Phase 3 is the final step in the drug-approval process.
The most common side effects were nausea and diarrhea. Most of these were mild and short-lived, the researchers said.
Gallbladder and pancreas problems (pancreatitis) were more common among those taking Victoza, but the numbers were small. About 10 percent of the participants in both groups left the study because of side effects.
Wilding has served as a consultant to Novo Nordisk, which funded the study.
For more on obesity, visit the U.S. National Library of Medicine.