Lilly shares gain after retatrutide adds weight-loss, sleep apnea, and diabetes benefits

Eli Lilly’s stock rose on June 8 after investors digested fresh Phase 3 data for retatrutide, the company’s investigational once-weekly obesity drug. The new results, disclosed June 6 and presented at the American Diabetes Association (ADA) 86th Scientific Sessions, add to Lilly’s pitch that the right obesity medicine can improve more than body weight, including common complications that often track alongside metabolic disease.

Retatrutide is designed to activate three hormone receptors involved in appetite and metabolism, acting as a “triple agonist” for GIP, GLP-1, and glucagon. In the company’s retatrutide Phase 3 program, Lilly reported outcomes from two studies: TRIUMPH-1 in adults with obesity or overweight and TRANSCEND-T2D-1 in adults with type 2 diabetes and inadequate glycemic control.

Lilly said TRIUMPH-1 was built as a master trial for obesity, with “nested” studies that targeted obesity-linked conditions. The company described two basket trials inside TRIUMPH-1: one evaluating knee osteoarthritis pain and another evaluating moderate-to-severe obstructive sleep apnea. Lilly said retatrutide met primary endpoints in each component at 80 weeks, with people on the higher 12 mg dose losing an average of 70.3 pounds (28.3%) and achieving clinically relevant improvements beyond weight.

The company reported that 65.3% of participants on retatrutide 12 mg achieved a body mass index below 30, a threshold that no longer meets the standard definition of obesity. It also said a pre-specified extension for participants starting with higher baseline BMI (at least 35) showed additional loss, with 12 mg participants losing an average of 85.0 pounds (30.3%) over 104 weeks. In the condition-focused endpoints, Lilly said retatrutide reduced knee osteoarthritis pain scores by up to 4.3 points (73.1%) and reduced obstructive sleep apnea severity by up to 36.1 events per hour (60.6%).

In TRANSCEND-T2D-1, Lilly reported that retatrutide achieved “primary and all key secondary endpoints” at 40 weeks in adults with type 2 diabetes who were managing with diet and exercise alone. The company said average A1C reductions were up to 2.0 percentage points from a baseline A1C of 7.9. It also disclosed achievement rates tied to typical diabetes goals, including up to 90% of participants reaching A1C below 7.0, up to 85% reaching A1C at or below 6.5, and up to 46% reaching a normoglycemia threshold below 5.7. Lilly added that at 40 weeks, weight loss on the 12 mg dose averaged 36.6 pounds (16.8%), and it said weight loss had not yet plateaued at that point.

Across both studies, Lilly said retatrutide improved some cardiovascular risk markers. For TRIUMPH-1 at 80 weeks, the company cited reductions “up to” 41.0% in triglycerides, 24.2% in non-HDL cholesterol, 12.3 mmHg in systolic blood pressure, and 9.5 cm in waist circumference. For TRANSCEND-T2D-1 at 40 weeks, it cited reductions “up to” 39.6% in triglycerides, 19.8% in non-HDL cholesterol, 6.4 mmHg in systolic blood pressure, and 4.9 in (12.4 cm) in waist circumference. It also said the safety profile was generally consistent with other incretin-based therapies, with nausea, diarrhea, constipation, and vomiting among the most common adverse events.

Lilly’s results come as competitors have pushed obesity drugs beyond a single “scale number,” with more attention on whether patients can keep taking therapy and whether treatment improves the conditions that drive healthcare costs. In industry commentary earlier this year, Axios noted that the obesity drug race is increasingly about keeping weight off and addressing long-term benefits and related outcomes, not just initial weight loss.

Still, key uncertainties remain. Lilly did not disclose, in the June 6 update, whether retatrutide has demonstrated long-term outcomes such as cardiovascular event reduction, nor did it provide detailed subgroup analyses that regulators and clinicians typically seek. The company also did not specify a timeline for regulatory filings or pricing, and it reiterated that retatrutide remains investigational and is “legally available only” to participants in its clinical trials.