Petrelintide
Once-weekly amylin analogue from Zealand and Roche aiming for double-digit weight loss with essentially placebo-level nausea, now heading into phase 3.
Also known as long-acting amylin analogue, ZP8396
Human RCT — Randomised controlled trials in humans, but not an approved product for this use.
ZUPREME-1 phase 2 reported up to 10.7% mean weight loss at 42 weeks versus 1.7% for placebo, with adverse-event discontinuations matching placebo. Zealand and Roche committed to phase 3 starting in the second half of 2026, and ZUPREME-2 in obesity with type 2 diabetes reads out later in 2026. Nothing is approved and no human long-term safety data exists.
How it works
Petrelintide is an acylated, non-aggregating amylin analogue engineered for once-weekly dosing and for a smoother exposure curve than earlier amylin agents. It activates amylin receptors - calcitonin receptor complexed with RAMPs - in the area postrema and hypothalamus, driving meal termination and reducing the hunger rebound that accompanies weight loss. The interesting result from ZUPREME-1 is tolerability rather than raw efficacy: no vomiting and no gastrointestinal discontinuations in the most effective arm, which is unheard of in this field. The working thesis is that amylin monotherapy can deliver GLP-1-adjacent weight loss with a far gentler side-effect profile and better lean-mass retention, but that thesis has not yet been tested in phase 3.
Targets: Amylin receptors (AMY1-3), Calcitonin receptor
Dosing
| Protocol | Dose | Frequency | Route |
|---|---|---|---|
| ZUPREME-1 phase 2 dosingSame day each week. | — | once weekly | subcutaneous |
- · Phase 2 used escalating once-weekly subcutaneous doses over 42 weeks reaching up to 10.7% mean weight loss. The exact maintenance milligram figures have not been consistently reported in public materials, and phase 3 dosing is not yet fixed, so no specific dose is given here rather than guessing at one.
Titration
Stepped weekly escalation was used in phase 2. The unusually clean tolerability means titration is likely to be less of a limiting factor than with incretins.
Cycling
Being developed as chronic therapy; no cycling rationale.
Pharmacology
- Half-life
- Long enough for once-weekly dosing; precise human half-life not publicly detailed.
- Onset
- Weight loss accrued steadily through 42 weeks in phase 2 with no plateau.
- Routes
- subcutaneous
- Molecule
- Acylated long-acting human amylin analogue
Handling
- Diluent
- Bacteriostatic water for research-grade material
- Typical mix
- 1 or 2 mL
- Lyophilised
- Refrigerate at 2-8 C.
- Reconstituted
- Refrigerated, use within about 28 days.
- Light sensitive
- Yes — keep it out of the light
Mixing
As with all amylin analogues, aggregation is the main handling risk - swirl gently and inspect for cloudiness.
Side effects
- commonNausea— Notably milder than incretins; largely confined to escalation.
- uncommonInjection-site reactions
- uncommonConstipation
Do not use if
- Pregnancy.
- Not enough long-term human safety data exists to define contraindications properly - this is a phase 2 molecule.
Combining it
- synergysemaglutide — Amylin plus GLP-1 is the logical combination and is being explored; separate receptors, additive satiety.
- redundantcagrilintide — Both are long-acting amylin analogues.
What to monitor
- · Weight and body composition.
- · Nausea during escalation.
- · Protein intake.
Legal status
Investigational; not approved anywhere. Research-chemical supply exists but purity and identity are unverifiable.
References
- Roche 2026, ZUPREME-1 phase 2 topline results in overweight and obesity (trial)
- Zealand Pharma petrelintide pipeline disclosures (other)
Mechanism in depth
Petrelintide's design thesis is that the nausea and vomiting which limit incretin dosing are not an inevitable price of appetite suppression, and that selective amylin receptor agonism can deliver most of the weight loss with something close to placebo-level gastrointestinal side effects. The ZUPREME-1 phase 2 result is the evidence for that: up to 10.7% mean weight loss at 42 weeks against 1.7% for placebo, with adverse-event discontinuation rates matching placebo. That last number is the interesting one. In incretin trials, discontinuation for adverse events typically runs several times placebo, and it is the main reason real-world adherence is so much worse than trial adherence. If a drug can produce double-digit weight loss that people actually keep taking, the area under the curve over three years may beat a stronger drug that a third of users abandon. The mechanistic argument for selectivity is that cagrilintide retains calcitonin receptor activity, and calcitonin receptor signalling in the area postrema is thought to contribute to the emetic response; a cleaner amylin receptor agonist should therefore separate satiation from nausea. Whether petrelintide's tolerability advantage is really due to receptor selectivity or simply to a flatter exposure profile has not been demonstrated. What is certain is that the weight loss is meaningfully below the incretins - 10.7% is roughly liraglutide territory - so the pitch is tolerability and lean-mass preservation, not maximum efficacy. Phase 3 was committed to for the second half of 2026, which means no long-term human safety data exists.
What usually goes wrong
The main risk is what is in the vial. Petrelintide is in phase 2 and 3, has no commercial supply, and anything sold under the name is unverifiable - the amylin analogues are structurally similar enough that a supplier could ship cagrilintide, or nothing, and no user could tell. Beyond that, the honest limitation is efficacy expectations: 10.7% is real and is roughly half of what tirzepatide delivers, so someone choosing petrelintide is explicitly trading efficacy for tolerability.
Bloodwork worth running
| Marker | When | Why it matters |
|---|---|---|
| Body composition by DEXA | Baseline and every 3-4 months. | The amylin class claim is lean-mass preservation. Without a scan you cannot tell whether you are getting it.Act if: No established threshold; use the proportion of loss that is lean tissue as the decision variable. |
| HbA1c and fasting glucose | Baseline and 3-monthly. | ZUPREME-2 in obesity with type 2 diabetes is still reading out. Amylin agonism suppresses glucagon, so glucose falls modestly.Act if: Hypoglycaemia on background insulin means cut the insulin. |
| Calcium and bone turnover markers | Baseline and annually. | The whole amylin class touches the calcitonin receptor to some degree, and long-term bone data does not exist for any of them.Act if: No established threshold - this is an acknowledged gap. |
Pharmacokinetics
- Crosses blood-brain barrier
- partial
- Accumulates
- Yes — doses stack before steady state
- Metabolism
- Presumed proteolytic degradation plus beta-oxidation of the acyl chain, by analogy with other acylated peptide analogues.
- Elimination
- Presumed catabolic.
Receptor targets
- Amylin receptors (AMY1R, AMY2R, AMY3R) — Not verified; described as a selective long-acting amylin receptor agonist
Meal-terminating satiation through the area postrema, slowed gastric emptying and postprandial glucagon suppression, with a weekly duration.
- Calcitonin receptor (CTR) — Reduced relative to cagrilintide, per the design rationale
Lower calcitonin receptor engagement is the claimed source of the improved gastrointestinal tolerability and would also reduce the theoretical bone-turnover concern that applies to cagrilintide.
Trials
- Petrelintide phase 1 programme Phase 1 · 2026
Safety, tolerability, pharmacokinetics and pharmacodynamics across two randomised controlled phase 1 trials.
- ZUPREME-1 Phase 2 · 42 weeks · 2025
Reported as up to 10.7% mean weight loss versus 1.7% for placebo, with adverse-event discontinuation matching placebo. Sponsor-reported; not confirmed against a peer-reviewed publication in this session.
What to expect, and when
Weight loss accrued steadily through 42 weeks in phase 2 without an obvious plateau, which is a favourable shape. Steady state and onset timing are not published in a form that could be verified.
Stacking and comparisons
The stated development strategy is petrelintide both as monotherapy and in combination with an incretin - Zealand and Roche have a semaglutide-like partner in development. In practice nobody outside a trial has access to real petrelintide, so stacking discussion is theoretical. The mechanistically sound combination is with a GLP-1 agonist, for the same reason CagriSema works: separate receptors, additive satiety, non-additive nausea.
Against cagrilintide: petrelintide is the more selective molecule with better reported tolerability and comparable weight loss, which if it holds up makes cagrilintide look first-generation. Against eloralintide: Lilly's selective amylin agonist reported around 20% at 48 weeks in phase 2, roughly double petrelintide's figure - if both results replicate, eloralintide is simply the better drug. Against semaglutide and tirzepatide: petrelintide loses clearly on weight and wins clearly on tolerability, and which of those matters more depends entirely on whether you can stay on an incretin.
Rough cost
Investigational; no legitimate supply exists. Grey-market listings exist but identity cannot be verified.
Genuinely uncertain
- No verifiable pharmacokinetic parameter values - the phase 1 papers exist but their numbers were not extracted in this session.
- The ZUPREME-1 efficacy and tolerability figures are sponsor communications and were not confirmed against a peer-reviewed publication.
- Sequence, acylation chemistry and receptor selectivity ratios are not verified.
- No dosing ladder is published in a verifiable form, so none is given.
- No long-term human safety data exists for any long-acting amylin analogue.
Papers
- Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Petrelintide for Weight Management: Two Randomized, Controlled Phase 1 Trials Braendholt Olsen M et al., Diabetes Obes Metab, 2026 · PMID 42017294
The only peer-reviewed petrelintide human pharmacology that could be resolved in this session.