Onswik (insulin efsitora alfa): FDA approval, pivotal trials and safety
Approved
Type
Therapeutic biologic · Subcutaneous
FDA-approved use
To improve glycemic control in adults with type 2 diabetes mellitus, as an adjunct to diet and exerciseWording from FDA's list of novel approvals.
FDA review
Standard review
Company
Eli Lilly
Application
BLA 761408
Specialty
Endocrinology
At a glance
Onswik is the second once-weekly basal insulin approved in the United States, for adults with type 2 diabetes. In the QWINT program it matched daily insulins on HbA1c; with its simplified fixed-step titration it caused less hypoglycemia than daily glargine and needed a median of 2 dose changes in a year instead of 8.
What it is and how it works
Efsitora alfa is a single-chain insulin fused to an antibody Fc fragment. Its large size slows clearance by the kidneys, binding to the neonatal Fc receptor protects it from breakdown, and lower affinity for the insulin receptor slows receptor-mediated clearance: together these give a week-long action. At the receptor it acts like human insulin.
928 adults with type 2 diabetes not previously treated with insulin, with or without GLP-1 receptor agonists.
Compared with
Insulin degludec once daily.
Primary endpoint
Change in HbA1c at week 52 (noninferiority margin 0.4 points).
Result
HbA1c fell from 8.21% to 6.97% with efsitora (-1.26 points) and from 8.24% to 7.05% with degludec (-1.17): difference -0.09 points (95% CI, -0.22 to 0.04), noninferior.
Other results
Time in range 64.3% versus 61.2% (difference 3.1 points; 95% CI, 0.1 to 6.1). Noninferior with and without GLP-1 receptor agonists.
Safety in the trial
Clinically significant or severe hypoglycemia 0.58 versus 0.45 events per participant-year (rate ratio 1.30; 95% CI, 0.94 to 1.78); no severe episodes with efsitora, six with degludec.
Phase 3, randomized (1:1), open-label, 52 weeks, testing a fixed-step regimen (four steps, changed no more than every 4 weeks) against daily glargine adjusted weekly.
Patients
795 adults with type 2 diabetes not previously treated with insulin.
Compared with
Insulin glargine U100 once daily.
Primary endpoint
Change in HbA1c at week 52 (noninferiority margin 0.4 points).
Result
HbA1c fell 1.19 points with efsitora and 1.16 points with glargine: difference -0.03 points (95% CI, -0.18 to 0.12), noninferior; superiority not shown.
Other results
Median of 2 dose adjustments in a year with efsitora versus 8 with glargine.
Safety in the trial
Clinically significant or severe hypoglycemia lower with efsitora: 0.50 versus 0.88 events per participant-year (rate ratio 0.57; 95% CI, 0.39 to 0.84).
How does Onswik (insulin efsitora alfa-gobe) compare with the alternatives (Awiqli (insulin icodec), Insulin glargine U100 or U300, Insulin degludec) for its approved use (to improve glycemic control in adults with type 2 diabetes mellitus, as an adjunct to diet and exercise)? Summarize head-to-head and indirect evidence, efficacy, safety and where each fits, with citations.
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Safety signals
Hypoglycemia is the main risk. Clinically significant or severe hypoglycemia was not significantly different from degludec in QWINT-2 (0.58 versus 0.45 events per participant-year) and lower than glargine in QWINT-1 (0.50 versus 0.88). The label says it is not recommended in type 1 diabetes because of increased severe hypoglycemia, warns about mix-ups between insulins, and says not to draw it from the pen into a syringe.
What it competes with
Onswik competes with Awiqli (insulin icodec), the first weekly basal insulin, and with daily basal insulins. The two weekly insulins have not been compared head to head in a published phase 3 trial.
Awiqli (insulin icodec)The first once-weekly basal insulin, approved March 2026.
Insulin glargine U100 or U300Daily basal insulin; the comparator in QWINT-1.
Insulin degludecDaily basal insulin; the comparator in QWINT-2.
GLP-1 receptor agonistsOften used before or with basal insulin.
Bottom line for clinicians
For adults with type 2 diabetes starting basal insulin, Onswik gives control equal to daily insulin with one weekly injection, and its fixed-step titration needs fewer adjustments. Not for type 1 diabetes.
Dosing, contraindications and full warnings are in the prescribing information.
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Last updated October 27, 2026 by 2 Minute Medicine.
For healthcare professionals. A summary of public FDA documents and published trials, not medical advice. Check the full prescribing information before prescribing.
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