The US Food and Drug Administration (FDA) has approved insulin efsitora alfa-gobe (Onswik), a once-weekly basal insulin, to improve glycemic control in adults with type 2 diabetes, based on 4 phase 3 QWINT trials, Eli Lilly and Company announced on September 24, 2026.¹
According to Eli Lilly, efsitora is designed to maintain steady basal insulin levels across a full 7-day dosing interval, reducing basal injections from approximately 365 to 52 per year vs once-daily basal insulin. The US decision is the fourth global approval for efsitora in type 2 diabetes, following actions in the European Union, Mexico, and Japan.¹
"For over a century, Lilly has been developing insulins that transformed diabetes care for millions of people worldwide, but delays in initiating treatment and the burden of daily injections can have a real impact on patients' day-to-day experience managing type 2 diabetes," said Kenneth Custer, PhD, executive vice president and president, Lilly Cardiometabolic Health. "Onswik offers a new once-weekly basal insulin option for patients and reflects our continued commitment to deliver innovative treatment options that expand choice and provide greater flexibility in how people manage type 2 diabetes."
Insulin efsitora efficacy across the QWINT phase 3 trials
The QWINT program comprised 4 randomized, open-label registration trials comparing once-weekly efsitora with once-daily insulin glargine U-100 or insulin degludec U-100 in more than 3,400 insulin-naive and insulin-experienced adults.¹ Each trial met its primary end point of noninferior hemoglobin A1c (HbA1c) reduction from baseline, with a prespecified noninferiority margin of 0.4 percentage points.¹⁻⁵
In QWINT-1 (N = 795), insulin-naive participants started efsitora at 100 U weekly.² Doses escalated every 4 weeks, as needed, through fixed steps of 150 U, 250 U, and 400 U toward a fasting glucose goal of 80 to 130 mg/dL.² At week 52, HbA1c fell by 1.19 percentage points with efsitora and 1.16 percentage points with glargine (estimated treatment difference [ETD], −0.03 percentage points; 95% CI, −0.18 to 0.12).²
Participants receiving efsitora required a median of 2 dose adjustments, compared with 8 for glargine.² QWINT-2 (N = 928) enrolled insulin-naive adults with or without glucagon-like peptide-1 (GLP-1) receptor agonist therapy.³ At week 52, efsitora reduced HbA1c by 1.26 percentage points vs 1.17 percentage points with degludec (ETD, −0.09 percentage points; 95% CI, −0.22 to 0.04).³
In QWINT-3 (N = 986), adults already treated with basal insulin achieved HbA1c reductions of 0.81 vs 0.72 percentage points at week 26 (ETD, −0.09 percentage points; 95% CI, −0.19 to 0.01).⁴
QWINT-4 (N = 730) enrolled adults on basal-bolus regimens, pairing efsitora or glargine with prandial insulin lispro.⁵ From a baseline HbA1c of 8.18% in both groups, HbA1c fell by 1.01 percentage points with efsitora and 1.00 percentage points with glargine at week 26, establishing noninferiority.⁵
Efsitora Hypoglycemia Rates and Safety Profile
In QWINT-1, efsitora produced 0.50 combined level 2 or level 3 hypoglycemia events per participant-year vs 0.88 with glargine (estimated rate ratio [ERR], 0.57; 95% CI, 0.39–0.84).² In QWINT-2, rates were 0.58 vs 0.45 events per participant-year with degludec (ERR, 1.30; 95% CI, 0.94–1.78), with no severe episodes reported for efsitora and 6 for degludec.³
Through 78 weeks of QWINT-3, the level 2 or 3 hypoglycemia rate was 0.84 vs 0.74 events per patient-year of exposure (ERR, 1.14; 95% CI, 0.83–1.56; P = .43).⁴ Serious adverse events occurred in 16% (103/655) of efsitora recipients and 11% (37/331) of degludec recipients, primarily cardiovascular events in both groups.⁴ Time in range (70–180 mg/dL) during weeks 48 to 52 of QWINT-2 was 64.3% with efsitora vs 61.2% with degludec (ETD, 3.1 percentage points; 95% CI, 0.1–6.1).³
In the basal-bolus population of QWINT-4, level 2 or 3 hypoglycemia rates were 6.6 vs 5.9 events per patient-year of exposure (ERR, 1.11; 95% CI, 0.85–1.44; P = .44). Nocturnal event rates were 0.67 vs 1.00 events per patient-year (ERR, 0.67; 95% CI, 0.44–1.01; P = .058).⁵ Serious adverse events occurred in 7% (25/365) of efsitora recipients and 6% (23/365) of glargine recipients.⁵
According to Eli Lilly, efsitora demonstrated an overall safety profile similar to the daily basal insulins studied. The label advises against use in type 1 diabetes due to increased risk of severe hypoglycemia and includes warnings for hypokalemia and for heart failure with concomitant thiazolidinedione use.¹
Common adverse reactions include hypoglycemia, hypersensitivity reactions, injection site reactions, lipodystrophy, pruritus, rash, peripheral edema, and weight gain.¹
The Onswik KwikPen will reach the US market in the coming months in 2 concentrations, U-500 (1,500 units per pen) and U-1,000 (3,000 units per pen). The U-500 pen delivers up to 400 units per injection in 5-unit increments, while the U-1,000 pen delivers up to 800 units in 10-unit increments.¹
REFERENCES:
- Eli Lilly and Company. U.S. Food and Drug Administration (FDA) approves Lilly's Onswik (insulin efsitora alfa-gobe), a once-weekly basal insulin injection treatment for adults living with type 2 diabetes. Published September 24, 2026. Accessed September 24, 2026. https://investor.lilly.com/news-releases/news-release-details/us-food-and-drug-administration-fda-approves-lillys-onswiktm
- 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
- Wysham C, Bajaj HS, Del Prato S, et al. Insulin efsitora versus degludec in type 2 diabetes without previous insulin treatment. N Engl J Med. 2024;391(23):2201-2211. doi:10.1056/NEJMoa2403953
- 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
- 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
