Comment on: LY2963016 Insulin Glargine: A Review in Type 1 and 2 Diabetes

To the Editor,

Lamb and Syed [1] reviewed the pharmacological and clinical properties of LY2963016 insulin glargine 100 U/ml (LY insulin glargine), a biosimilar to insulin glargine 100 U/ml (Gla-100, Lantus^®). They considered several studies that compared LY insulin glargine and Gla-100 and concluded that the efficacy and safety profiles of these two insulins are similar.

I would like to draw to readers’ attention that, while the authors refer to Gla-100 as the reference insulin, this definition is only provided within the abstract and introduction. The main body of the article simply referred to “reference insulin glargine,” and I believe this may create some confusion. Indeed, since 2015, in most countries, a different formulation of insulin glargine has also been available in addition to insulin glargine 100 U/ml (Gla-100). This formulation is insulin glargine 300 U/ml (Gla-300), which has different characteristics (a prolonged duration of action, more even steady-state pharmacokinetic/pharmacodynamic [2] profile, and lower incidence of hypoglycemia [3, 4] than Gla-100).

To avoid potential misinterpretation by the reader on the similarities of LY insulin glargine and the reference molecule, I believe it should be clarified that Gla-100 is the “reference insulin” in the studies reviewed, not Gla-300.

Best regards,

Riccardo Perfetti