Two pre-conference data releases published Sunday in advance of the European Congress on Obesity now sit alongside this week’s Medicare GLP-1 Bridge announcement and demolish a concern that has limited GLP-1 prescribing in older patients: that the drugs are less effective in adults 65 and over. Both orforglipron / Foundayo and semaglutide produce clinically meaningful weight loss in 65+ adults, with safety profiles comparable to younger populations.

The timing of the data releases is not coincidental. Lilly and Novo Nordisk both timed their elderly-subgroup publications to align with the Medicare GLP-1 Bridge launch on July 1. Each company is building the evidence case for a patient population about to gain access to its products at a $50/month copay.

The Orforglipron 65+ Subgroup Data

A post-hoc analysis of the ATTAIN-1 and ATTAIN-2 trials, published May 11 ahead of presentation at ECO, reports orforglipron efficacy in adults 65 and older. The analyses pooled 616 randomized participants — 196 from ATTAIN-1 (obesity without T2D) and 420 from ATTAIN-2 (obesity with T2D).

ATTAIN-1 (65+ subgroup, obesity without T2D), Week 72 weight loss:

• 6 mg orforglipron: −7.9%
• 12 mg orforglipron: −11.3%
• 36 mg orforglipron: −13.0%
• Placebo: −1.6%

All three orforglipron doses produced statistically significant weight loss versus placebo. The 36 mg dose efficacy of 13.0% in adults 65+ is roughly comparable to the broader ATTAIN-1 population result (approximately 14.9% across all ages), suggesting modest but not clinically dispositive age-related attenuation of effect.

ATTAIN-2 (65+ subgroup, obesity with T2D), Week 72 weight loss:

• 6 mg orforglipron: −7.5%
• 12 mg orforglipron: −8.3%
• 36 mg orforglipron: −12.2%
• Placebo: −2.3%

Safety in the 65+ subgroup was consistent with the overall ATTAIN populations and the GLP-1 class. No new safety signals emerged specific to older adults.

The Semaglutide 65+ Pooled Analysis

A separate analysis, also published May 11 ahead of ECO, pooled data from six STEP trials (STEP 1, 3, 4, 5, 8, 9) to assess semaglutide 2.4 mg efficacy in adults 65 and older. The pooled cohort included 358 randomized participants across the six trials.

Pooled STEP analysis, 65+ subgroup, Week 68:

• Semaglutide 2.4 mg weight loss: −15.4%
• Placebo: −5.1%
• Mean waist circumference change with semaglutide: −14.3 cm vs. −6.0 cm placebo

The 15.4% weight loss figure is striking because it is statistically indistinguishable from the younger-adult STEP populations (approximately 15–17% across the original trial publications). The age-related attenuation that had been hypothesized — based on physiological differences in older adults — does not appear in the data.

Threshold achievement rates with semaglutide versus placebo:

• ≥10% weight loss: 66.5% vs. 15.5%
• ≥15% weight loss: 46.8% vs. 6.4%
• ≥20% weight loss: 28.6% vs. 2.7%

Safety profile was acceptable for the population. Adverse event rates were comparable to the general STEP population (89.1% vs. 84.5%), with serious adverse events slightly higher (19.0% vs. 12.7%) — a result expected given that older adults carry more baseline comorbidities and concomitant medication exposure.

Why the Timing Matters

The publication dates for both data releases — Sunday May 10–11, less than 48 hours before ECO Day 1 — are designed to set the narrative ahead of the conference. They also coincide precisely with the Medicare GLP-1 Bridge announcement that confirmed implementation details the same week.

Medicare’s GLP-1 Bridge program covers Wegovy (injectable and pill), Zepbound KwikPen, and Foundayo at a $50 monthly copay for eligible Part D and MA-PD beneficiaries starting July 1, 2026. The program runs through December 31, 2027 and gives roughly 65 million Medicare beneficiaries access to branded GLP-1s at substantially below list-price cost.

The clinical and financial barriers that previously limited GLP-1 prescribing in the Medicare population are both being addressed in the same week. The clinical question — does this drug work in older adults? — now has data answers in the 12–15% weight loss range for both the orforglipron 36 mg and semaglutide 2.4 mg doses. The financial question — can my patient afford this? — has a $50/month answer starting July 1.

What the Data Doesn’t Address

Three honest scope limits.

Both analyses are post-hoc subgroup studies, not prospective trials designed to assess GLP-1 efficacy in older adults. Post-hoc analyses can be statistically reliable but are not equivalent to prospectively powered trials. A dedicated 65+ trial would provide stronger evidence; the post-hoc subgroup data is the strongest evidence currently available.

The 65+ population is heterogeneous. The 65–70 cohort, the 70–80 cohort, and the 80+ cohort have substantially different comorbidity profiles, frailty risks, and treatment goals. The subgroup analyses pool across these subpopulations, which means clinically meaningful variation within the 65+ population may be obscured.

The trials enrolled patients meeting the broader inclusion criteria, not patients with the specific clinical profiles that drive obesity prescribing in 65+ populations — heart failure, advanced osteoarthritis, severe sleep apnea, frailty, polypharmacy. Real-world 65+ patients may have different efficacy profiles than the trial subpopulations.

What This Means

For prescribers managing 65+ patients with obesity: the evidence base is now adequate to support GLP-1 therapy when clinically appropriate. The pre-ECO data, combined with the Medicare Bridge access window, removes the two most-cited barriers to prescribing in this population.

For 65+ patients and their families: $50/month access to a branded GLP-1 with documented efficacy in the same age group is meaningfully different from the cost-prohibitive list-price environment that has prevailed until now. Whether GLP-1 therapy is the right treatment for any individual patient is a clinical conversation with a qualified provider — but the evidence and access barriers are both lower than they were a week ago.

For the broader Peptidings audience: this is a continued instance of clinical evidence and regulatory direction aligning around the legitimate, FDA-approved, clinician-supervised channels for GLP-1 access. The gray-market peptide ecosystem operates in increasingly unfavorable contrast to the formal channels.

References

1. Daily Orforglipron Treatment Reduces Weight and Blood Sugar in Seniors. News-Medical. May 11, 2026. News-Medical
2. Post-Hoc Analysis of Orforglipron in Adults Over 65. MedicalXpress. May 11, 2026. MedicalXpress
3. Semaglutide Shows Sustained Weight Loss Benefits in Older Adults. News-Medical. May 11, 2026. News-Medical
4. Pooled Analysis Reveals Semaglutide Shows Good Efficacy in Older Adults Aged Over 65. MedicalXpress. May 11, 2026. MedicalXpress
5. Orforglipron Obesity Treatment for Adults 65+ Data to Be Presented at ECO 2026. GeneOnline. May 11, 2026. GeneOnline