Summary: In 795 insulin-naive adults with type 2 diabetes, once-weekly fixed-dose insulin efsitora was noninferior to once-daily glargine for change in HbA1c at 52 weeks (between-group difference -0.03 percentage points, 95% CI -0.18 to 0.12). Superiority was not shown (P=0.68), though efsitora produced less clinically significant or severe hypoglycaemia (rate ratio 0.57).
PICO Summary
| Element | Detail |
|---|---|
| Population | 795 adults with type 2 diabetes who had not previously received insulin therapy; 52-week, phase 3, open-label, treat-to-target randomised trial (multicentre). |
| Intervention | Once-weekly insulin efsitora alfa, fixed-dose regimen (started at 100 U weekly; stepped adjustments every 4 weeks to fixed doses of 150, 250 or 400 U), targeting fasting glucose 80 to 130 mg/dL (n approximately 397). |
| Comparison | Once-daily insulin glargine U100, titrated weekly or more often by a standard algorithm to the same glycaemic goals (n approximately 398). |
| Outcome | Primary endpoint (change in HbA1c at 52 weeks): efsitora -1.19 vs glargine -1.16 percentage points; between-group difference -0.03 percentage points (95% CI -0.18 to 0.12), confirming noninferiority (margin 0.4 percentage points). Superiority not shown (P=0.68). Combined clinically significant (glucose <54 mg/dL) or severe hypoglycaemia: 0.50 vs 0.88 events per participant-year (rate ratio 0.57, 95% CI 0.39 to 0.84). Mean weekly insulin dose 289.1 vs 332.8 U (difference -43.7 U, 95% CI -62.4 to -25.0); median dose adjustments 2 vs 8. |
Weekly efsitora vs daily glargine in insulin-naive type 2 diabetes
RCT · insulin-naive type 2 diabetes · 52 weeks
Once-weekly efsitora was noninferior to daily glargine for HbA1c reduction at 52 weeks, with less hypoglycaemia, a lower insulin dose, and fewer titration steps. Superiority was not shown.
Expert Commentary
This phase 3 trial met its prespecified noninferiority endpoint: once-weekly fixed-dose efsitora was noninferior to daily glargine for HbA1c reduction over 52 weeks, with a between-group difference of essentially zero. The verdict is therefore equivalence on glycaemic control, not superiority, which was formally not demonstrated (P=0.68); the earlier framing of efsitora as significantly better should be read as comparable. The accompanying signals are clinically attractive: a lower rate of clinically significant or severe hypoglycaemia, a lower total weekly insulin requirement, and far fewer titration steps, all of which speak to convenience and tolerability rather than added glucose-lowering potency. The principal caveat is the open-label design, which leaves titration behaviour and hypoglycaemia reporting vulnerable to bias and tempers confidence in the secondary safety differences. The trial was funded by the manufacturer (Eli Lilly), so independent replication and longer follow-up remain desirable. Can I use this with my patients? Not yet, because efsitora is investigational and not approved, but the data support it as a future option for insulin-naive type 2 diabetes patients who would value a weekly, simply titrated basal insulin. Clinicians should await regulatory approval and pragmatic outcome data before changing practice.
References
Rosenstock J, Bailey T, Connery L, et al. Weekly Fixed-Dose Insulin Efsitora in Type 2 Diabetes without Previous Insulin Therapy. N Engl J Med. 2025;393(4):325-335. doi:10.1056/NEJMoa2502796