Once-weekly insulin efsitora alfa versus once-daily insulin degludec in adults with type 1 diabetes (QWINT-5): a phase 3 randomised non-inferiority trial

Background: Insulin efsitora alfa (efsitora) is a once-weekly basal insulin. This phase 3 study aimed to assess the efficacy and safety of efsitora compared with insulin degludec (degludec) in adults with type 1 diabetes.

Methods: This randomised, 52-week, parallel-design, open-label, treat-to-target non-inferiority study conducted at 82 global health-care centres, randomly assigned (1:1) adults (ie, those aged ≥18 years) with type 1 diabetes glycated haemoglobin A_1c (HbA_1c) 7·0-10·0% (53·0-85·8 mmol/mol) to efsitora (n=343) or, degludec (n=349), both in combination with insulin lispro. The primary endpoint was the change in HbA_1c from baseline to week-26 (non-inferiority margin=0·4%). The trial was registered at ClinicalTrials.gov (NCT05463744) and is completed.

Findings: Between Aug 12, 2022, and May 7, 2024, of 893 participants enrolled, 692 (77%) participants were randomly assigned to once-weekly efsitora or once-daily degludec, and 623 (90%) participants completed the study. Mean HbA_1c decreased from 7·88% (62·66 mmol/mol) at baseline to 7·41% (57·5 mmol/mol) at week 26 with efsitora and from 7·94% (63·3 mmol/mol) at baseline to 7·36% (56·9 mmol/mol) at week 26 with degludec. Mean HbA_1c change from baseline to week 26 was -0·51% with efsitora and -0·56% with degludec (estimated treatment difference 0·052%, 95% CI -0·077 to 0·181; p=0·43), confirming a non-inferiority margin of 0·4% for efsitora compared with degludec. Rates of combined level 2 (<54 mg/dL [3·0 mmol/L]) or level 3 severe hypoglycaemia were higher with efsitora compared with degludec (14·03 vs 11·59 events per patient year of exposure; estimated rate ratio 1·21, 95% CI 1·04 to 1·41; p=0·016) during weeks 0-52, with the highest rates during weeks 0-12. Severe hypoglycaemia incidence was higher with efsitora (35 [10%] of 343) versus degludec (11 [3%] of 349) during weeks 0-52. Overall incidence of treatment-emergent adverse events was similar across treatment groups. One death not related to the study treatment occurred in the degludec group.

Interpretation: In adults with type 1 diabetes, once-weekly efsitora showed non-inferior HbA_1c reduction compared with daily insulin degludec. Higher rates of combined level 2 or level 3 hypoglycaemia and greater incidence of severe hypoglycaemia in participants treated with efsitora compared with participants treated with degludec might suggest the need for additional evaluation of efsitora dose initiation and optimisation in people with type 1 diabetes.

Funding: Eli Lilly and Company.