Lilly’s Weight Loss Mastery Shows Benefits in Menopause, Sleep Apnea, More

Lilly Unveils Retatrutide and Foundayo Data at ADA Scientific Sessions

Eli Lilly presented new data for its pipeline assets, retatrutide and Foundayo, at the American Diabetes Association Scientific Sessions. The triple agonist retatrutide demonstrated significant weight loss of 28.3% (70 pounds) at 80 weeks in the Phase 3 TRIUMPH-1 trial, alongside reductions in osteoarthritis knee pain by 73% and moderate-to-severe sleep apnea severity by 60%. In the Phase 3 TRANSCEND-T2D-1 trial for patients with diabetes, retatrutide achieved A1C reductions of up to 2% and 16.8% (36.6 pounds) weight loss at 40 weeks. Additionally, the oral GLP-1 Foundayo showed weight loss benefits in women across all stages of menopause in the Phase 3 ATTAIN program, with perimenopausal women losing up to 14.4% (31.4 pounds) and postmenopausal women losing 14.1% (28.2 pounds) at 72 weeks.

• Retatrutide, Lilly's triple agonist, showcased impressive broad benefits in the Phase 3 TRIUMPH-1 trial, achieving an average weight loss of 28.3% or 70 pounds over 80 weeks. Beyond weight, it significantly reduced osteoarthritis knee pain by 73% and moderate-to-severe sleep apnea severity by 60%, highlighting its potential to address multiple obesity-related complications simultaneously.
• In the Phase 3 TRANSCEND-T2D-1 trial involving patients with diabetes, retatrutide demonstrated strong glycemic control, leading to A1C reductions of up to 2%. Concurrently, patients experienced substantial weight loss, averaging 16.8% or 36.6 pounds over 40 weeks, with nearly half achieving normal A1C levels, underscoring its efficacy in managing both diabetes and associated weight.
• Lilly's oral GLP-1, Foundayo, presented compelling data from the Phase 3 ATTAIN program, showing significant weight loss in women across all stages of menopause. Perimenopausal women achieved up to 14.4% (31.4 pounds) weight loss, while postmenopausal women lost 14.1% (28.2 pounds) at 72 weeks, addressing a critical need for weight management during hormonal changes.

Retatrutide: Addressing Obesity and Its Related Complications

Beyond obesity, retatrutide is being investigated for several therapeutic indications, with type 2 diabetes mellitus representing the most advanced clinical development program. A phase 2, randomised, double-blind, double-dummy, placebo-controlled and active comparator-controlled trial was conducted across 42 research centers in the USA, enrolling 281 adults aged 18-75 years with type 2 diabetes, glycated hemoglobin levels of 7.0-10.5%, and BMI of 25-50 kg/m². Participants were randomly assigned to receive once-weekly injections of placebo, 1.5 mg dulaglutide, or various retatrutide maintenance doses ranging from 0.5 mg to 12 mg with different escalation protocols. The primary endpoint assessed change in HbA1c from baseline to 24 weeks, with secondary endpoints including change in HbA1c and bodyweight at 36 weeks.

Preclinical investigations have explored retatrutide's therapeutic potential in diabetic kidney disease using db/db mouse models. In these studies, mice received intraperitoneal injections of retatrutide at 10 nmol/kg for 10 weeks, with comparisons made against liraglutide and tirzepatide at equivalent doses. The intervention model focused on assessing blood glucose control, weight reduction, serum biochemical indicators, and renal inflammation and fibrosis markers. Retatrutide demonstrated superior effectiveness in improving renal function compared to the comparator agents, particularly in suppressing pro-inflammatory cytokines including TNF-α, caspase-1, and NLRP3, as well as pro-fibrotic factors such as fibronectin, α-SMA, and collagen I.

Additional indications under investigation include polycystic ovarian syndrome (PCOS), where retatrutide is reportedly seeking FDA approval, and metabolic dysfunction-associated steatohepatitis (MASH), which remains in late-stage clinical development. For PCOS, research has focused on the enhanced weight loss and insulin sensitivity improvements provided by the triple receptor agonism, with studies demonstrating improvements in PCOS-specific symptoms including dysmenorrhea and dysmorphic ovarian morphology. However, detailed intervention models for these latter indications were not comprehensively described in the available literature.

Foundayo: A New Option for Menopausal Weight Management

Recent literature identifies key unmet needs in obesity treatment centered around access barriers, personalized care approaches, and specialized population management. Research consistently highlights significant gaps between treatment availability and patient access, alongside the need for more individualized therapeutic strategies.

Access and Communication Barriers
• Major barriers to obesity medication initiation include insurance restrictions (38%), concerns about side effects (37%), and cost (31%)
• Communication gaps exist where healthcare provider discussions frequently address side effects and administration, but treatment duration and lifestyle integration discussions are less consistent
• Clinical inertia, polypharmacy, and socioeconomic disparities hinder treatment adherence and medical therapy implementation
• Addressing systemic barriers, stigma, education, and access challenges is essential to maximize utility of obesity pharmacotherapy in clinical practice

Treatment Duration and Continuity Challenges
• 56% of patients expected to be on obesity medications for limited periods (20% anticipating less than one year, 28% less than two years)
• Anticipated treatment duration varies with out-of-pocket costs, creating sustainability concerns
• Most patients (91%) using GLP-1 receptor agonists had previously attempted a median of 3 unique weight management strategies prior to medication initiation
• Need for early intervention, robust patient-provider communication, equitable access, and financial support to optimize treatment outcomes

Specialized Population Needs
• Heart failure patients require multidisciplinary team approach including cardiologists, primary care physicians, endocrinologists, nephrologists, pharmacists, dietitians, and mental health professionals
• South Asian populations need region-specific adaptations including lower BMI thresholds (>25 kg/m²) and specialized screening approaches
• Genetic screening requirements identified for severe obesity patients, with 17.1% carrying two or more rare variants in separate genes indicating oligogenic inheritance patterns

Individualized Treatment Approaches
• Anti-obesity treatments should be individualized and multidisciplinary, moving beyond one-size-fits-all approaches
• Need for algorithms addressing long-term medications based on drugs that increase or decrease body weight, results, contraindications, and medication recommendations
• 94% of patients with obesity have at least one comorbidity requiring coordinated care management strategies

Lilly's Expanding Footprint in the Obesity Treatment Landscape

The obesity treatment landscape has undergone a fundamental transformation over the past five years, driven predominantly by the emergence of highly effective pharmacological interventions that rival surgical outcomes. The approval of semaglutide 2.4 mg for chronic weight management in April 2021, following the landmark STEP 1-4 trial results, marked a pivotal moment with demonstrated weight loss of 15-17% and evidence of cardioprotection. This was followed by tirzepatide's approval in 2022, which achieved unprecedented weight loss of up to 22.5% in non-diabetic individuals with obesity—results comparable to some types of bariatric surgery. Current clinical practice data shows dramatic efficacy differences among anti-obesity medications, with phentermine achieving ≥5% weight loss in 87.2% of patients at 6 months, while tirzepatide demonstrates the highest absolute weight reduction of 9-12 kg at 6 months depending on dose.

The therapeutic pipeline continues to expand beyond traditional GLP-1 receptor agonists toward novel multi-target approaches that promise even greater efficacy. Triple receptor agonists such as retatrutide (targeting GLP-1/GIP/glucagon) have progressed to phase 3 trials with early data suggesting weight loss potential in the 22.5% range at highest doses. Combination therapies like cagrisema, which combines cagrilintide with semaglutide 2.4 mg, are also advancing to phase 3 development with similar weight loss expectations. The pediatric obesity treatment landscape has simultaneously evolved, with liraglutide becoming the first GLP-1 receptor agonist approved for children aged 12-17 years in 2020, while ongoing trials are evaluating semaglutide in pediatric populations.

Clinical practice patterns reflect this pharmacological revolution, with referral data from 2022-2024 showing increasing utilization of GLP-1 receptor agonists, particularly semaglutide which comprises 78.3% of pharmacological referrals. Notably, patients receiving shared medical appointments demonstrated significantly higher anti-obesity medication prescription rates (49.8% versus 12.3%) and superior weight loss outcomes compared to traditional care models. The treatment paradigm has also expanded to encompass cardiovascular outcome considerations, with ongoing trials including SELECT, SURPASS, SUMMIT, and SURMOUNT-MMO examining long-term cardiovascular benefits, while emerging evidence links weight reduction to decreased obesity-related cancer risk across multiple time intervals.

Lilly's Dual Metabolic Breakthroughs Reshape Obesity and Diabetes Care

The recent data presented by Eli Lilly heralds a transformative period in the management of obesity and type 2 diabetes, showcasing a dual approach that promises to redefine therapeutic expectations. At the forefront is retatrutide, a groundbreaking triple agonist that has demonstrated an unprecedented level of weight loss, reaching 28.3% at 80 weeks in the TRIUMPH-1 trial. This remarkable efficacy extends beyond mere weight reduction, showing significant improvements in obesity-related comorbidities such as osteoarthritis knee pain and moderate-to-severe sleep apnea. For patients with type 2 diabetes, retatrutide also delivered robust glycemic control, with A1C reductions up to 2%. This positions retatrutide not just as another weight loss drug, but as a comprehensive metabolic modulator capable of addressing multiple facets of these complex diseases, potentially setting a new benchmark for pharmacotherapy.

Complementing this injectable powerhouse is Foundayo, an oral GLP-1 that offers a different, yet equally impactful, strategic advantage. Its demonstrated weight loss benefits in women across all stages of menopause address a specific, often challenging, patient population. The convenience of an oral formulation could significantly enhance patient adherence and expand access to effective treatment, particularly for individuals who prefer non-injectable options.

However, this exciting progress comes with important considerations. While the efficacy of retatrutide is compelling, the need for long-term cardiovascular outcome trials (CVOTs) is paramount. Previous observations of dose-dependent increases in heart rate and mild-to-moderate cardiac arrhythmias underscore the importance of thoroughly evaluating its cardiovascular safety profile. Furthermore, the high acquisition costs of these advanced incretin therapies, as evidenced by real-world data showing significant increases in medication expenditure, present a substantial barrier to widespread access and long-term patient persistence. Managing common gastrointestinal side effects, such as nausea and vomiting, will also be crucial for patient tolerability and sustained adherence. As the field moves towards more potent multi-receptor agonists and accessible oral formulations, balancing groundbreaking efficacy with comprehensive safety, affordability, and patient-centric care will be key to realizing the full potential of these next-generation metabolic treatments.