Zealand Pharma A/S and Roche Holding AG have strengthened the case for petrelintide as a potential alternative or complement to GLP-1-based obesity medicines after a Phase 2 trial showed up to 9.2% mean weight reduction over 28 weeks in people who were overweight or obese and also had type 2 diabetes. The once-weekly amylin analog met the primary endpoint across all three tested dose groups, with weight loss ranging from 7.4% to 9.2% compared with 2.0% for placebo, while the highest-dose response was accompanied by an HbA1c decline of as much as 0.65% versus a 0.23% increase in the placebo group.
The topline results are particularly important because Zealand Pharma and Roche are no longer deciding whether petrelintide deserves late-stage development. The partners have already started the registrational ZUPREME Phase 3 program across approximately 7,000 participants, meaning the October 7 data serve as another validation point for a development strategy already moving at commercial scale. The larger question is whether petrelintide can preserve what has emerged as its most differentiated feature so far: meaningful weight loss with gastrointestinal tolerability that appears relatively close to placebo.
That question matters in an obesity market where absolute weight reduction remains critical but is no longer the only competitive measure. Treatment persistence, nausea, vomiting, diarrhea, constipation, dose-escalation burden and the willingness of patients to remain on chronic therapy are increasingly important as Eli Lilly and Company, Novo Nordisk A/S, Roche Holding AG and numerous biotechnology companies expand their next-generation metabolic pipelines. Petrelintide is being developed partly around the thesis that amylin biology could deliver a different balance between efficacy and tolerability than conventional incretin approaches.
How much weight did petrelintide produce in the ZUPREME-2 diabetes trial?
ZUPREME-2 enrolled 220 participants in the United States who were overweight or obese and had type 2 diabetes treated with metformin with or without an SGLT2 inhibitor. Participants entered the trial with an average body mass index of 36.3 kilograms per square meter and mean baseline HbA1c of 8.0%, giving the study a population in which both weight reduction and glucose control were clinically relevant treatment objectives.
After 28 weeks, all three once-weekly petrelintide dose groups produced statistically significant reductions in body weight compared with placebo. Mean weight loss under the efficacy estimand ranged from 7.4% to 9.2% across active-treatment groups, while placebo recipients lost 2.0%. Zealand Pharma said results remained broadly consistent under the treatment-regimen estimand, an important detail because large differences between estimands can sometimes indicate that treatment discontinuations or missing data materially affected the apparent magnitude of benefit.
The trial used dose escalation every four weeks, with the escalation period lasting as long as 16 weeks before patients entered maintenance dosing. That approach is relevant when evaluating tolerability because many gastrointestinal adverse events associated with metabolic drugs occur during dose increases rather than after patients have stabilized on maintenance treatment.
Petrelintide also produced improvements in waist circumference, glucose-related measures and other metabolic parameters evaluated as secondary endpoints, although the company has not yet released the full detailed dataset. Full ZUPREME-2 findings are expected to be presented at a future scientific meeting, where clinicians will be able to examine dose-by-dose efficacy, safety, responder thresholds and additional cardiometabolic effects more closely.
Why could the HbA1c result matter as much as the weight-loss number?
The latest study was the first major petrelintide dataset specifically focused on people with obesity or overweight and established type 2 diabetes. That is an important test because metabolic drugs that perform strongly in people without diabetes do not always reproduce identical weight-loss effects in patients whose glucose regulation, insulin sensitivity and background medication use differ substantially.
Petrelintide reduced HbA1c by as much as 0.65 percentage points from baseline, while placebo recipients experienced an increase of 0.23 percentage points. Across the active-treatment groups, the placebo-adjusted HbA1c benefit ranged from approximately 0.61 to 0.88 percentage points. Those reductions provide early evidence that petrelintide may improve glycemic control while reducing weight rather than functioning purely as a weight-management agent.
That dual effect is strategically valuable because obesity and type 2 diabetes frequently overlap, creating a large population for whom treatment decisions are shaped by both body weight and glucose management. A therapy that lowers weight meaningfully while also improving HbA1c could potentially compete for patients who might otherwise be considered for GLP-1 or dual-incretin medicines, although direct comparative trials would be needed before concluding that petrelintide offers a superior clinical profile.
The result also supports Roche’s broader ambition to build a cardiovascular, renal and metabolic franchise rather than a single obesity product. The pharmaceutical group has been expanding across incretin, amylin and combination approaches, allowing it to test whether different biological mechanisms can be matched to different patient types rather than relying on one therapeutic pathway.
Why is the 1.9% gastrointestinal discontinuation rate attracting attention?
The most strategically interesting feature of ZUPREME-2 may not be the 9.2% headline weight-loss figure. Only 1.9% of participants receiving petrelintide discontinued treatment because of gastrointestinal adverse events, compared with 1.7% in the placebo group. The most frequently reported adverse events were gastrointestinal, but Zealand Pharma said the vast majority were mild and primarily occurred during dose escalation.
That pattern is consistent with earlier petrelintide data. In the 42-week ZUPREME-1 Phase 2 study involving people with overweight or obesity without type 2 diabetes, the therapy produced up to 10.7% mean weight loss compared with 1.7% for placebo. At the maximally effective dose in that study, no vomiting was reported and no participants discontinued because of gastrointestinal adverse events.
Taken together, the trials create a consistent early narrative around tolerability, although Phase 3 development will provide a much more demanding test because thousands of patients will be exposed across broader populations and for longer periods. Small differences that appear insignificant in a few hundred participants can become clinically important when a medicine is used by millions of people over many years.
The potential commercial importance is straightforward. Obesity drugs are intended for chronic use, but a medicine cannot deliver long-term weight control if large numbers of patients stop taking it because of nausea, vomiting or other adverse effects. A product offering moderately lower peak weight loss than the most potent incretin agents could still occupy an important market position if it proves easier for patients to tolerate and remain on consistently.
What is petrelintide and how does an amylin drug differ from GLP-1 medicines?
Petrelintide is a long-acting analog of amylin, a hormone naturally produced by pancreatic beta cells and released alongside insulin after food intake. Amylin signaling contributes to satiety and helps regulate how quickly people feel full, providing a biological route to reduce caloric intake without relying entirely on the GLP-1 receptor pathway that dominates the current obesity-drug market.
Zealand Pharma designed petrelintide for once-weekly subcutaneous administration and with physical properties intended to support combination or co-formulation with other peptide drugs. That engineering becomes especially important because Roche is not viewing petrelintide solely as a standalone medicine. The partners also plan to combine it with Roche’s GLP-1/GIP dual agonist enicepatide, previously known as CT-388.
The strategic logic is to use different hormonal pathways to achieve greater weight reduction while potentially avoiding the need to push one mechanism to doses that become difficult to tolerate. Amylin could therefore serve either as a primary therapy for people seeking meaningful weight loss with a potentially gentler tolerability profile or as one component of a more potent combination regimen for people requiring greater weight reduction.
That approach mirrors a broader change across obesity research. Companies are increasingly exploring amylin analogs, glucagon combinations, muscle-preserving agents and other mechanisms that could supplement or diversify treatment beyond first-generation GLP-1 products.
How does ZUPREME-2 compare with the earlier ZUPREME-1 trial?
ZUPREME-1 enrolled 493 people who were overweight or obese but did not have type 2 diabetes. After 42 weeks, participants receiving petrelintide achieved up to 10.7% mean body-weight reduction compared with 1.7% for placebo, with the highest-performing dose continuing to show weight loss through the later stages of treatment.
The study also produced the tolerability findings that initially strengthened industry interest in the asset. At the maximally effective dose, there were no vomiting events and no discontinuations caused by gastrointestinal adverse events, while diarrhea and constipation rates remained in the single-digit range and were similar to placebo. Nearly all participants in the strongest-performing group reached the intended maintenance dose.
ZUPREME-2 extends that profile into diabetes, where metabolic disease can make drug development more complicated. Achieving up to 9.2% weight loss after only 28 weeks in a type 2 diabetes population, together with improved HbA1c and limited gastrointestinal discontinuation, reduces the risk that the earlier tolerability and efficacy profile was restricted to patients without diabetes.
The two studies should not be compared as if they were head-to-head trials because treatment duration, populations, doses and other design features differed. The more important observation is that petrelintide has now produced meaningful weight loss with similar tolerability characteristics across two distinct Phase 2 populations.
Why did Roche commit up to $5.3 billion to petrelintide?
Roche entered the program through a global collaboration and licensing agreement with Zealand Pharma in 2025 that carries potential consideration of up to $5.3 billion. The arrangement included $1.65 billion in upfront cash payments, up to $1.2 billion in development milestones largely linked to Phase 3 progression and up to $2.4 billion in sales-related milestones.
The economics demonstrate how highly Roche valued the opportunity before the latest Phase 2 results arrived. Zealand Pharma and Roche will share profits and losses 50-50 in the United States and Europe, while Roche holds exclusive commercialization rights elsewhere and Zealand Pharma can receive tiered double-digit royalties reaching the high teens on net sales outside those jointly commercialized regions.
Roche is also responsible for commercial manufacturing and supply, addressing one of the largest challenges facing smaller biotechnology companies trying to compete in the obesity market. Successful obesity drugs require enormous manufacturing capacity because patient populations can reach millions, making commercial scale almost as important as clinical efficacy.
For Zealand Pharma, the partnership provides large-pharma infrastructure while preserving substantial economics in the two most commercially important Western markets. For Roche, the agreement adds an amylin franchise that can be developed independently and combined with its own incretin assets, giving the company multiple potential routes into a market currently dominated by Eli Lilly and Company and Novo Nordisk A/S.
What does the 7,000-patient Phase 3 program need to prove?
The registrational ZUPREME program includes three Phase 3 trials and is expected to enroll approximately 7,000 people in total. ZUPREME-3 will evaluate petrelintide in people with overweight or obesity without type 2 diabetes, while ZUPREME-4 will focus on participants who also have type 2 diabetes. ZUPREME-5 extends the program into people with overweight or obesity and established cardiovascular disease.
The inclusion of a cardiovascular-disease population is particularly notable because the obesity market is increasingly being judged on outcomes that extend beyond kilograms lost. Cardiovascular-event reduction, diabetes prevention, kidney effects, sleep apnea, liver disease and other comorbidities have become important drivers of reimbursement and clinical positioning as obesity treatment becomes integrated more deeply into chronic-disease management.
Phase 3 will also determine whether the attractive gastrointestinal profile remains intact when petrelintide is used in a much larger population. Investors and clinicians will be watching total discontinuation rates, nausea, vomiting, diarrhea, constipation, injection-site reactions, gallbladder complications and other safety signals associated with long-term metabolic treatment.
The large program therefore creates two simultaneous tests. Roche and Zealand Pharma must show that petrelintide produces enough weight reduction to compete meaningfully in a market where double-digit and even substantially higher losses are increasingly expected, while also proving that improved tolerability is strong enough to become a genuine clinical advantage rather than simply an encouraging Phase 2 observation.
Could petrelintide become more valuable as part of a combination with Roche’s enicepatide?
The standalone program may be only one part of the eventual franchise. Roche and Zealand Pharma are also developing a fixed-dose combination of petrelintide with enicepatide, Roche’s dual GLP-1/GIP receptor agonist previously known as CT-388. A Phase 2 program has been planned to evaluate whether combining the mechanisms can deliver greater weight reduction while retaining acceptable tolerability.
That concept could become commercially important if petrelintide proves capable of offsetting some of the treatment-experience limitations that can occur when incretin drugs are pushed to higher doses. Rather than competing directly with GLP-1 biology, the amylin mechanism could become a complementary component of a next-generation regimen.
Roche therefore has several strategic options. Petrelintide could succeed as a standalone treatment for patients prioritizing tolerability, enicepatide could compete as a potent incretin-based therapy, and a combined product could target patients requiring greater efficacy. A portfolio with those choices could allow physicians to tailor treatment more closely to individual needs rather than relying on a single obesity drug for every patient.
Whether that flexibility translates into commercial advantage will depend on Phase 3 and combination data. The obesity market is evolving rapidly, and competing companies are pursuing oral therapies, monthly injections, multi-receptor agonists and medicines designed to protect muscle mass, meaning petrelintide will enter a considerably more competitive environment if it eventually reaches approval.
Why did Zealand Pharma shares barely move despite positive petrelintide data?
Zealand Pharma shares closed October 7 at DKK 249.40 in Copenhagen, down about 0.7% for the session, despite the positive ZUPREME-2 announcement. That muted reaction contrasts with the large share-price moves often associated with obesity-trial readouts and suggests the market had already incorporated substantial expectations around a program that had previously produced positive Phase 2 data and entered Phase 3 development.
Recent sentiment around Zealand Pharma has also been complicated by another obesity program. Shares fell sharply earlier in October after investors focused on treatment discontinuations related to gastrointestinal adverse events in Phase 3 studies of survodutide, the separate GLP-1/glucagon drug licensed to Boehringer Ingelheim. Petrelintide is a different molecule with a different mechanism and development partnership, but both assets contribute to Zealand Pharma’s broader valuation.
The subdued response may therefore reflect investors balancing several factors at once: encouraging petrelintide efficacy, unusually low gastrointestinal discontinuation, an already initiated Phase 3 program, expectations that positive ZUPREME-2 data were largely anticipated, and lingering volatility around Zealand Pharma’s wider obesity portfolio. The share move should not be interpreted as evidence that the clinical results were weak.
From a strategic perspective, the more important development is that petrelintide has now cleared another biological hurdle while Roche commits resources to a development program involving thousands of patients. The value inflection is increasingly shifting away from small Phase 2 studies and toward Phase 3 confirmation, regulatory execution and evidence that the tolerability proposition survives at commercial scale.
Can petrelintide become a credible alternative to today’s leading obesity drugs?
Petrelintide does not yet have the evidence required to claim superiority over approved GLP-1 or dual-incretin treatments. Eli Lilly and Company and Novo Nordisk A/S have established extensive clinical datasets, regulatory approvals and commercial infrastructure, while their leading medicines can generate greater weight reduction than has so far been reported with petrelintide monotherapy.
The opportunity may instead lie in differentiation. Obesity is a heterogeneous chronic disease, and not every patient needs or tolerates the most aggressive available weight-loss approach. A once-weekly therapy producing meaningful weight loss with low gastrointestinal discontinuation could occupy an important position if Phase 3 confirms the profile seen so far.
The latest ZUPREME-2 results strengthen that possibility because they show that the profile extends into type 2 diabetes rather than being confined to obesity alone. The combination of up to 9.2% weight loss, improved HbA1c and a gastrointestinal discontinuation rate close to placebo gives Roche and Zealand Pharma a credible foundation for arguing that treatment experience may matter alongside headline efficacy.
The decisive evidence will now come from the roughly 7,000-patient Phase 3 program. If petrelintide can reproduce meaningful weight reduction across people with and without diabetes, preserve low treatment-discontinuation rates and demonstrate benefits in patients with cardiovascular disease, Roche could emerge with a differentiated amylin franchise at a time when the obesity market is broadening well beyond the first wave of GLP-1 medicines.
