REGULATORY STATUS — A biosimilar is a biologic product that is highly similar in composition, strength, and biological properties and has no clinically meaningful differences in safety, purity, and potency to the FDA-approved reference product. Although Merilog has been designated as a biosimilar to the reference product NovoLog, it has not received interchangeability status from the FDA. Merilog cannot be substituted as a lower-cost alternative to NovoLog by the pharmacist without permission from the prescriber. 

CLINICAL STUDIES — FDA approval of Merilog was based on the results of an open-label trial (GEMELLI 1) in 597 patients with type 1 or type 2 diabetes. Patients were randomized to receive mealtime Merilog or NovoLog, each in addition to long-acting insulin glargine (Lantus). The mean decrease in A1C levels from baseline to 26 weeks with Merilog was noninferior to that with NovoLog (-0.38% with Merilog vs -0.30% with NovoLog). Fasting plasma glucose, postprandial glucose excursions, and adverse effects were also similar between the two groups.1 

DOSAGE AND ADMINISTRATION — Like NovoLog, Merilog is supplied in 3-mL prefilled pens and 10-mL multidose vials containing 100 units/mL of insulin aspart. The drug should be administered subcutaneously into the abdomen, thigh, buttocks, or upper arm 5-10 minutes before a meal. The injection site should be rotated to minimize the risk of lipodystrophy and cutaneous amyloidosis. 

COST — The wholesale acquisition cost (WAC) for one Merilog 3-mL pen is $26.90 and for one 10-mL vial is $69.60; the cost for one NovoLog 3-mL pen is $27.90 and for one 10-mL vial is $72.30.2 The Medicare Part D negotiated rate for a 30-day supply of NovoLog is $119.

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