Cagrilintide Research Study: Phase 1b and Phase 2 Design Ledgers

Cagrilintide research study is best read as a study-design question, not as a single headline result. The phase 2 once-weekly trial (PMID 34798060) and the earlier phase 1b multiple-dose study (PMID 33894838) asked different questions, used different comparators, and reported different endpoints. Keeping those ledgers separate prevents a result from one design being presented as evidence from the other.

Research question: what was each trial designed to learn?

The phase 2 study evaluated a dose-response relationship for once-weekly cagrilintide in adults with overweight or obesity. Its primary question was the percentage change in bodyweight at week 26, with safety and tolerability assessed alongside the efficacy endpoint. The phase 1b study instead examined safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) when multiple doses of cagrilintide were given with semaglutide 2.4 mg. Its primary endpoint was treatment-emergent adverse events through follow-up, with concentration and exposure measures as secondary or exploratory endpoints. PMID 34798060; PMID 33894838.

Phase 2 group ledger: PMID 34798060

This multicentre, randomised, double-blind, placebo-controlled and active-controlled dose-finding trial ran at 57 sites in ten countries. Eligible participants were adults aged at least 18 years without diabetes, with a body-mass index of at least 30 kg/m², or at least 27 kg/m² with hypertension or dyslipidaemia. Randomisation assigned participants in a 6:1 ratio to once-weekly subcutaneous cagrilintide (0.3, 0.6, 1.2, 2.4, or 4.5 mg), once-daily liraglutide 3.0 mg, or volume-matched placebo groups. The treatment period was 26 weeks, including dose escalation of up to six weeks, followed by six weeks without treatment.

Between 1 March and 19 August 2019, 706 participants were assigned to cagrilintide dose groups (100-102 per dose), 99 to liraglutide, and 101 to placebo. The primary endpoint was percentage bodyweight change from baseline to week 26, analysed with both a trial-product estimand (assuming adherence) and a treatment-policy estimand (regardless of adherence). The paper reports mean reductions of 6.0%-10.8% (6.4-11.5 kg) across cagrilintide doses versus 3.0% (3.3 kg) with placebo under the trial-product estimand; the 4.5 mg cagrilintide group was reported as 10.8% versus 9.0% with liraglutide 3.0 mg. These values are results of this trial’s estimands and population.

Permanent treatment discontinuation occurred in 73 participants (10%), mostly because of adverse events (30 participants, 4%); 29 participants (4%) withdrew. Gastrointestinal adverse events were reported in 41%-63% of cagrilintide participants versus 32% with placebo, with nausea reported in 20%-47% versus 18%. The authors concluded that cagrilintide produced significant bodyweight reductions and was well tolerated in this study, while the registered phase 2 design and six-week off-treatment follow-up define the limits of what it tested.

Phase 1b group ledger: PMID 33894838

This randomised, placebo-controlled, multiple-ascending-dose phase 1b trial recruited otherwise healthy adults aged 18-55 years with a body-mass index of 27.0-39.9 kg/m² at one US centre. Six sequential overlapping cohorts assigned participants 3:1 to once-weekly subcutaneous cagrilintide (0.16, 0.30, 0.60, 1.2, 2.4, or 4.5 mg) or matched placebo, each in combination with once-weekly subcutaneous semaglutide 2.4 mg. Doses were co-escalated at four-week intervals to the target over 16 weeks, followed by four weeks at target and five weeks of follow-up; no lifestyle intervention was part of the study design.

Of 285 screened individuals, 96 were randomised and 95 were exposed and included in safety and full-analysis datasets. The primary endpoint was the number of treatment-emergent adverse events from baseline through follow-up. Secondary PK endpoints included AUC_{0-168 h} and C_max around weeks 19-20; exploratory measures included half-life, time to maximum concentration, clearance, volume of distribution, bodyweight, glycaemic parameters, and hormones.

The authors report dose-proportional cagrilintide exposure without an effect on semaglutide exposure or elimination. Cagrilintide half-life was 159-195 hours with median time to maximum concentration of 24-72 hours in the tested groups. At week 20, the exploratory bodyweight analysis reported mean reductions of 15.7% (SE 1.6) with cagrilintide 1.2 mg plus semaglutide 2.4 mg and 17.1% (SE 1.5) with cagrilintide 2.4 mg plus semaglutide 2.4 mg, versus 9.8% (SE 1.2) in pooled placebo cohorts; estimated treatment differences were -6.0% (95% CI -9.9 to -2.0) and -7.4% (95% CI -11.2 to -3.5), respectively. The 4.5 mg cagrilintide plus semaglutide 2.4 mg group showed a mean reduction of 15.4% (SE 1.3) versus 8.0% (SE 2.2) with matched placebo, with an estimated treatment difference of -7.4% (95% CI -12.8 to -2.1). These are week-20 exploratory results from this single-centre combination study of 95 exposed participants, not dose instructions or a product effect. Glycaemic parameters improved across treatment groups independently of cagrilintide dose. Of 566 adverse events in 92 participants, 207 (37%) were gastrointestinal; most were mild to moderate, and the proportion with at least one adverse event was similar across groups. The authors described the combination as well tolerated but stated that larger and longer trials were needed.

Endpoint and result table

What changed from phase 1b to phase 2?

The phase 1b study prioritised short-term safety and exposure characterisation for a cagrilintide-semaglutide combination in a small, healthy cohort. The phase 2 study expanded to 57 sites, used cagrilintide monotherapy arms with liraglutide and placebo comparators, and made week-26 bodyweight change the primary endpoint. This is a change in question and scale, not a direct validation of one trial by the other. The phase 1b PK results cannot be substituted for the phase 2 efficacy estimand, and the phase 2 weight result cannot establish the phase 1b combination’s PK behaviour.

What the papers can and cannot answer

• They can describe the named populations, randomisation, comparators, dose schedules, time windows, endpoints, and reported results under each protocol.
• They can show how endpoint choice and comparator affect interpretation of a cagrilintide study.
• They cannot establish that a supplied research material is the trial material or that a catalogue product reproduces a trial result.
• They cannot turn study doses, routes, or adverse-event frequencies into instructions, safety guarantees, or treatment recommendations.
• They cannot replace the registered protocol, full methods, statistical analysis, or longer-term evidence.

Keep trial evidence separate from material records

The public Cagrilintide Research Material Profile concerns catalogue and material-record terminology. It is not a trial report. A paper citation should remain linked to its own population, intervention, comparator, endpoint, and limitation. Do not attach the phase 2 or phase 1b results to a product page, batch, or material record as if the paper had tested that item.

Funding and competing-interest context: Both PubMed records identify Novo Nordisk A/S as the funder. Their conflict-of-interest statements also report company employment, shareholdings, consulting, speaking, research funding, or investigator sponsorship for named authors. These disclosures do not invalidate the results, but they are part of the context for interpreting the study reports.

References

• Lau DCW et al. Once-weekly cagrilintide for weight management in people with overweight and obesity: phase 2 trial. PMID 34798060.
• Enebo LB et al. Safety, tolerability, PK and PD of multiple cagrilintide doses with semaglutide 2.4 mg: phase 1b trial. PMID 33894838.

Research scope: This summary reports study details from the cited source and does not provide medical, veterinary, dosing, administration, safety, or treatment guidance. It does not represent a product-use recommendation.