FDA Approves a Second Once-Weekly Basal Insulin: What the QWINT Data Show

Once-weekly basal insulin options for adults with type 2 diabetes have doubled in 2026, with the FDA approval of insulin efsitora alfa-gobe (Onswik) following the March clearance of insulin icodec-abae (Awiqli). Efsitora pairs a fixed weekly regimen with two high-concentration pen formulations built for a wide dosing range.

On a recent episode of Diabetes Dialogue, cohosts Diana Isaacs, PharmD, and Natalie Bellini, DNP, reviewed the September 24, 2026, approval of Eli Lilly's efsitora, its supporting phase 3 evidence, and practical considerations for prescribing.

Watch the full episode discussing the FDA’s approval of efsitora alfa-gobe here.

The approval rests on four phase 3 QWINT trials comparing efsitora with daily insulin glargine U-100 or insulin degludec U-100. Efsitora met the primary endpoint of noninferior A1C reduction in each study, with reductions ranging from 0.81 to 1.26 percentage points. Because insulin trials target comparability rather than superiority, these results support substituting efsitora for daily basal insulin without sacrificing glycemic control.

Hypoglycemia data offer a clearer point of differentiation. Rates of clinically significant or severe hypoglycemia were similar to daily comparators across the program, but insulin-naive participants in QWINT-1 experienced 43% fewer events than those receiving glargine. A flatter steady-state profile may account for the gap, since glargine varies between individuals and may not provide full 24-hour coverage in every patient.

Titration strategy likely contributes as well, and optimal initiation and titration approaches are still being refined, as occurred with icodec. The indication excludes type 1 diabetes, where trials showed higher hypoglycemia rates, although clinicians can envision future use cases in this population.

Dosing logistics differ meaningfully from icodec, a U-700 formulation dosed in 10-unit increments. The efsitora U-500 pen delivers up to 400 units per injection in five-unit increments, while the U-1000 pen delivers up to 800 units in 10-unit increments for patients with higher requirements. Dividing weekly doses by seven gives the daily equivalent, so a 400-unit injection corresponds to roughly 57 units per day.

With two weekly basal insulins now available, clinicians face a new learning curve around pen concentrations, dose increments, and quantities per prescription. Efsitora's hypoglycemia profile in insulin-naive patients may make it an appealing option for basal insulin initiation, where reducing injection burden could help address delays in starting therapy.

Editors’ Note: Isaacs reports disclosures with Dexcom, Abbott, Lilly, Novo Nordisk, Medtronic, Insulet, and others. Bellini reports disclosures with Abbott Diabetes Care, MannKind, Povention Bio, and others.

References

1. 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

2. Philis-Tsimikas A, Bergenstal RM, Bailey TS, et al. Once-weekly insulin efsitora alfa versus once-daily insulin degludec in adults with type 2 diabetes currently treated with basal insulin (QWINT-3): a phase 3, randomised, non-inferiority trial. Lancet. 2025;405(10497):2279-2289. doi:10.1016/S0140-6736(25)01044-X

3. Blevins T, Dahl D, Pérez Manghi FC, et al. Once-weekly insulin efsitora alfa versus once-daily insulin glargine U100 in adults with type 2 diabetes treated with basal and prandial insulin (QWINT-4): a phase 3, randomised, non-inferiority trial. Lancet. 2025;405(10497):2290-2301. doi:10.1016/S0140-6736(25)01069-4