What is insulin glargine‑yfgn (Semglee) and how is it dosed for patients with type 1 or type 2 diabetes?

What is Insulin Glargine-yfgn (Semglee)?

Insulin glargine-yfgn (Semglee) is a biosimilar U-100 insulin glargine product that may be used interchangeably with the reference product (Lantus) when unavailable, providing comparable glycemic control. 1

Classification and Mechanism

• Insulin glargine-yfgn is a long-acting basal insulin analog designed to provide 24-hour glucose control with a relatively constant, peakless insulin profile. 2, 3
• The molecule is modified from human insulin by three amino acids, creating a stable compound that is soluble at acidic pH (≈4.0) but precipitates at the neutral pH of subcutaneous tissue, resulting in delayed, sustained absorption. 4
• It primarily controls blood glucose by suppressing hepatic glucose production between meals and during sleep, mimicking physiologic basal insulin secretion. 1, 2

Pharmacokinetic Profile

• Onset of action: Approximately 1 hour after subcutaneous injection 2, 3
• Peak action: No pronounced peak—provides relatively constant insulin levels over 24 hours 2, 5
• Duration of action: Approximately 24 hours, allowing once-daily dosing 2, 3

This peakless profile distinguishes insulin glargine from intermediate-acting insulins like NPH, which have pronounced peaks at 6–8 hours. 2

FDA-Approved Indications

• Indicated to improve glycemic control in adult and pediatric patients (≥6 years) with type 1 or type 2 diabetes mellitus. 3
• Not recommended for treatment of diabetic ketoacidosis. 3

Dosing Guidelines

Type 1 Diabetes

• Start with approximately one-third of total daily insulin requirements as basal insulin glargine; use short-acting prandial insulin to satisfy the remainder. 3
• Basal insulin typically comprises 40–60% of total daily dose in patients on multiple daily injection regimens. 1
• Must be used concomitantly with short-acting insulin to cover prandial needs. 2, 3

Type 2 Diabetes

• For insulin-naive patients: Start at 0.2 units/kg or up to 10 units once daily. 1, 3
• Patients with type 2 diabetes generally require higher doses (approximately ≥1 unit/kg/day) due to insulin resistance. 1
• Can be used alone or combined with oral antidiabetic agents or GLP-1 receptor agonists. 1

Dose Titration

• Increase dose by 10–15% or 2–4 units once or twice weekly until fasting blood glucose target is met. 1
• If basal insulin dose exceeds 0.5 units/kg/day and A1C remains above target, consider adding GLP-1 receptor agonists or prandial insulin rather than continuing to escalate basal insulin alone. 1, 6

Administration Guidelines

• Administer subcutaneously once daily at the same time every day (can be given at any time, but consistency is critical). 1, 3
• Inject into abdominal area, thigh, or deltoid; rotate injection sites within the same region to reduce risk of lipodystrophy and localized cutaneous amyloidosis. 3
• Do not administer intravenously, via insulin pump, or mix with any other insulin or solution due to its acidic pH. 1, 3
• Solution should appear clear and colorless with no visible particles; discard if cloudy or discolored. 3

Biosimilar Substitution

• Semglee (insulin glargine-yfgn) and Basaglar are biosimilar U-100 insulin glargine products that may be substituted for Lantus when unavailable, providing comparable glycemic control. 1
• When switching between insulin glargine formulations (e.g., U-100 to U-300), medical supervision with appropriate dose adjustments is required, as products are not interchangeable unit-for-unit. 1

Clinical Advantages Over NPH Insulin

• Significantly lower risk of nocturnal hypoglycemia compared to NPH insulin while achieving equivalent glycemic control. 1, 5, 4, 7
• More consistent absorption and more stable 24-hour glucose control due to peakless profile. 1, 5
• Greater treatment satisfaction reported by patients due to once-daily dosing and reduced hypoglycemia risk. 5, 7

Critical Safety Considerations

• Never share pens, syringes, or needles between patients, even if the needle is changed—risk of blood-borne pathogen transmission. 3
• Contraindicated during episodes of hypoglycemia and in patients with hypersensitivity to insulin glargine or excipients. 3
• Repeated injections into areas of lipodystrophy or localized cutaneous amyloidosis can cause hyperglycemia; sudden change to unaffected area may cause hypoglycemia. 3
• Increase frequency of blood glucose monitoring during any insulin regimen changes. 3

Storage Requirements

• Unopened vials/pens: Refrigerate at 2°C–8°C (36°F–46°F). 1
• In-use vials/pens: May be kept at room temperature to reduce injection-site irritation. 1
• Inspect visually before each use; any clumping, frosting, or precipitation indicates loss of potency. 1

Special Populations

• Elderly hospitalized patients with reduced oral intake should start with reduced total daily dose of 0.1–0.15 units/kg/day, given mainly as basal insulin. 1
• Puberty: Insulin requirements may increase dramatically to as much as 1.5 units/kg/day due to hormonal influences. 1
• Pregnancy: Higher doses may be needed, though definitive studies confirming benefits are lacking. 8

When Glargine May Not Last 24 Hours

• In some patients, insulin glargine may not provide full 24-hour coverage; consider dividing the dose into two daily injections if glucose control deteriorates before the next dose. 1
• Twice-daily dosing is particularly useful for patients with type 1 diabetes who have persistent glycemic variability or require high basal insulin doses. 1