Maintenance Trials and Drug Responders
Week Of May 9 – May 15, 2026
Lilly’s two maintenance trials, SURMOUNT-MAINTAIN and ATTAIN-MAINTAIN, read out at the European Congress on Obesity (ECO) 2026: step down to low-dose Zepbound or switch to oral Foundayo and you keep most of the weight off. Both trials also had placebo arms, and those patients regained substantially, confirming that stopping the drug entirely does not work. The Trial Spotlight walks through what the trials tested and what they don’t address, including whether people can ever successfully come off these drugs without regain. The Mechanism Explained covers a related ECO 2026 angle: Novo’s focus on “early responder” sub-analyses to extract 21.6% and 27.7% headlines from existing trials, and why segmentation has become important for pharma.
Some interesting things I saw this week: on the basic science side, this Nature paper on a brain reward circuit affected by next-generation weight-loss drugs adds a mechanistic angle to how these newer agents may be working beyond a simple appetite-suppression story; and if you enjoy knowing some of the more than 40-year history behind GLP-1s, this EASD video piece with some of the main researchers at the core of the discoveries is fascinating.
🔥 THIS WEEK’S KEY DEVELOPMENTS
Wegovy demonstrates weight loss and heart protection across all menopause stages
Novo Nordisk presented data at ECO 2026 showing that Wegovy (semaglutide) 7.2 mg achieved average weight loss of 22.6% in premenopausal women and approximately 19.8% in perimenopausal and postmenopausal women over 72 weeks in the STEP UP trial. Post-hoc analysis of the SELECT trial demonstrated cardiovascular risk reductions of 42% in perimenopausal and 13% in postmenopausal women compared to placebo. Additionally, real-world evidence associated Wegovy with a 42–45% lower risk of migraine and a 25% lower risk of depression compared to those using menopausal hormone therapy alone.
Press | Trials: NCT05646706 | NCT03574597 | Mechanism: GLP-1 receptor agonist (semaglutide)
High-dose Wegovy demonstrates 28% weight loss in early responders
Novo Nordisk presented sub-analyses from the Phase 3b STEP UP trial at the 2026 European Congress on Obesity, showing that semaglutide 7.2 mg (Wegovy) achieved a mean weight loss of 20.7% at week 72 compared to 17.5% for the 2.4 mg dose. Among early responders who lost at least 15% of their weight by week 24, those on the 7.2 mg dose reached an average weight loss of 27.7% by the end of the trial. Body composition data further indicated that 84% of the total weight loss across both semaglutide doses was attributed to fat mass reduction while maintaining functional muscle strength.
Press | Trials: NCT05646706 | Mechanism: GLP-1 receptor agonist (semaglutide)
Lilly reports SURMOUNT-MAINTAIN and ATTAIN-MAINTAIN maintenance results at ECO 2026
In SURMOUNT-MAINTAIN, participants continuing Zepbound (tirzepatide) at maximum tolerated dose held their prior weight loss over 52 weeks; those stepping down to a 5 mg dose regained 5.6 kg on average. In ATTAIN-MAINTAIN, participants switching from injectable Wegovy or Zepbound to oral Foundayo (orforglipron) regained 0.9 kg and 5.0 kg respectively. Both trials had placebo arms, which regained substantially more. The Trial Spotlight below discusses what these trials tested and did not test.
Press | Trials: NCT06584916 | NCT06047548 | Mechanism: GLP-1/GIP dual agonist (tirzepatide); GLP-1 receptor agonist (orforglipron)
📰 PRESS
FDA halts Aardvark’s ARD-101 and ARD-201 over cardiac safety concerns
Press | Mechanism: TAS2R (bitter taste receptor) agonist
Apotex launches generic Ozempic (Apo-Semaglutide) in Canada
Press | Mechanism: GLP-1 receptor agonist (semaglutide)
Wegovy pill achieves 21.6% weight loss and improved mobility in early responders (OASIS 4)
Press | Trials: NCT05564117 | Mechanism: GLP-1 receptor agonist (oral semaglutide 25 mg)
Endoscopic sleeve gastroplasty outperforms oral semaglutide in head-to-head weight-loss study at ESGE 2026 (12.7% vs 8.7% at 6 months)
Press | Mechanism: GLP-1 receptor agonist (oral semaglutide) vs endoscopic procedure
Hims reports $33 million impact from GLP-1 medication pivot
Eli Lilly pauses India obesity campaign following regulatory scrutiny
Press | Mechanism: GLP-1 receptor agonist
Hepta’s AI blood test predicts patient response to GLP-1 medications
Press | Mechanism: GLP-1 receptor agonist
💡 TRIAL SPOTLIGHT
Educational spotlight selected by editors
Less Drug, Still Drug: What Lilly’s Two Maintenance Trials Actually Tested
At the ECO 2026 conference, Eli Lilly presented data from two maintenance trials, SURMOUNT-MAINTAIN and ATTAIN-MAINTAIN, framed as showing patients can switch therapies and maintain weight loss. However, a closer look at the trial designs reveals a more nuanced story about chronic disease management rather than treatment cessation. SURMOUNT-MAINTAIN tested a dose reduction, not a switch, randomizing patients who had lost approximately 20% of their body weight on a 60-week open-label lead-in of maximum-tolerated Zepbound (tirzepatide) to either continue that dose, step down to a 5 mg dose, or take a placebo. While the maximum dose group maintained 100% of their loss, the 5 mg step-down arm regained an average of 5.6 kg, demonstrating that even a lower dose of the same drug allows for partial weight regain compared to the induction dose.
The ATTAIN-MAINTAIN trial evaluated switching from injectable Zepbound or Wegovy to oral Foundayo (orforglipron) versus placebo, but critically, not versus continuing the original injectable. The results showed that switching from dual-agonist Zepbound to the single-agonist Foundayo resulted in a 5.0 kg average regain, a predictable outcome when stepping down the mechanism of action, whereas the same-mechanism switch from Wegovy to Foundayo led to only a 0.9 kg regain. Both trials confirm that a lower-intensity incretin regimen is superior to stopping treatment altogether, where placebo arms saw substantial weight rebound.
Ultimately, these studies reinforce the view of obesity as a chronic condition requiring continuous therapy, much like statins for cardiovascular risk. They introduce commercially significant, potentially more tolerable or convenient maintenance options like lower-dose injectables or oral agents. What they do not demonstrate is that patients can stop incretin therapy and sustain their weight loss. The central question of whether an exit ramp from this drug class exists remains unanswered, with all current data suggesting that discontinuation leads to significant weight regain over time. The operating assumption for now remains lifelong treatment, with these trials mapping out the first options for a less intensive, long-term therapeutic journey.
ClinicalTrials.gov: NCT06047548 (SURMOUNT-MAINTAIN, tirzepatide step-down) | NCT06584916 (ATTAIN-MAINTAIN, orforglipron switch) | NCT05822830 (SURMOUNT-5, the run-in parent trial) | Lilly press release
🔬 MECHANISM EXPLAINED
Understanding the science behind the therapeutics
Beyond the Headline Number: How ‘Early Responder’ Segmentation Is Becoming Pharma’s New Fighting Axis (Example drugs: Semaglutide, Tirzepatide, Orforglipron)
As headline weight-loss numbers saturate across the maturing obesity pipeline with semaglutide at 15% and tirzepatide at 21%, the competitive battleground has shifted from trial-wide averages to early-responder segmentation, a transition vividly illustrated by Novo Nordisk’s ECO 2026 sub-analyses demonstrating that patients hitting specific early milestones achieve dramatically higher final numbers. By stratifying completed Phase 3 trials, Novo revealed that early responders, defined as hitting a 5% milestone on the 25 mg oral Wegovy in OASIS 4, achieved an impressive 21.6% weight loss at 64 weeks compared to the 16% trial average while driving clinical mobility improvements for 80% of functionally impaired participants. Those hitting a steeper 15% threshold by week 24 on the high-dose 7.2 mg injectable in STEP UP ultimately reached a striking 27.7% reduction at 72 weeks with 84% of that loss attributed to fat mass rather than lean tissue.
This clinical heuristic operates on the biological premise that a productive initial trajectory predicts long-term receptor responsiveness and tolerability, a concept further reinforced by demographic slicing that showed premenopausal women hitting 22.6% loss on the 7.2 mg dose and perimenopausal SELECT participants seeing a 42% cardiovascular event reduction alongside major real-world drops in migraine and depression risk versus hormone therapy alone. Much like the early 2000s statin market evolved past baseline lipid-lowering into risk-stratified high and moderate-intensity regimens, slicing data by responder status gives companies a rhetorically powerful tool to position assets, assert superiority over competitors like orforglipron or Viking’s oral VK2735 (which itself showed 80% of patients hitting a 10% benchmark at 13 weeks), and pinpoint the ideal candidates for the step-down maintenance protocols currently being operationalized in Lilly’s SURMOUNT-MAINTAIN and ATTAIN-MAINTAIN trials.
However, these segmentation figures remain hypothesis-generating, post-hoc selections from mature trials utilizing inconsistent definitions across the landscape, varying from 5% to 15% milestones depending on the study design, which invites critical questions regarding the exact proportion of patients who actually qualify as early responders and what alternative mechanisms those left behind might require. While pharmaceutical developers are advancing this profiling to guide future sequencing and maintenance paradigms, payers and regulators have not yet adopted responder-based criteria, meaning commercial coverage and formulary placement will continue to operate on flat label-level efficacy averages until this clinical framing catches up with policy over the next 12 to 24 months.
ClinicalTrials.gov: NCT05564117 (OASIS 4, oral sema 25 mg) | NCT05646706 (STEP UP, high-dose sema 7.2 mg) | NCT03574597 (SELECT, semaglutide CVOT) | NCT05822830 (SURMOUNT-5, tirzepatide vs semaglutide) | NCT05869903 (ATTAIN-1, orforglipron Phase 3)
🆕 NEWLY REGISTERED TRIALS (industry programs from 9 registered in last week)
Macupatide and Eloralintide Phase II evaluating the efficacy of these novel agents alone or in combination for weight management in adults with obesity or overweight (Eli Lilly, n=400)
[Weight Loss/Efficacy]
Trials: NCT07589608 | Mechanism: GIP receptor agonist + amylin receptor agonist (no GLP-1 component)
Petrelintide with Enicepatide (RO7795068) Phase II dose-finding study evaluating the safety and efficacy of this combination therapy for weight management in adults with obesity or overweight (Hoffmann-La Roche, n=486)
[Weight Loss/Efficacy]
Trials: NCT07589686 (ZYNERGY) | Mechanism: Amylin receptor agonist (petrelintide) + biased GLP-1/GIP dual agonist (enicepatide/CT-388)
NNC0487-0111 Phase I evaluating pharmacokinetics and tolerability in participants with reduced liver function compared to those with normal liver function (Novo Nordisk, n=35)
[Weight Loss/Efficacy]
Trials: NCT07587710 | Mechanism: Unimolecular GLP-1/amylin co-agonist (amycretin)
NNC0497-0040 Phase I evaluating safety and effect in healthy participants and individuals with overweight or obesity, including those with Type 1 Diabetes (Novo Nordisk, n=146)
[Weight Loss/Efficacy]
Trials: NCT07578584 | Mechanism: Mechanism not disclosed
This newsletter compiles publicly available information from press releases, news sources, and trial registries. Not investment advice.
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