BUDGET IMPACT ANALYSIS OF KIRSTY AND MERILOG IN THE TREATMENT OF DIABETES MELLITUS FROM A U.S. PAYER PERSPECTIVE
Author(s)
Rosemond S. Amamoo, MD, MPH, MS1, Roselyn S. Amamoo, MD, MPH, MS1, Ivo Abraham, PhD1, Karen MacDonald, PhD2;
1R. Ken Coit College of Pharmacy, University of Arizona, Center for Health Outcomes and Pharmacoeconomic Research, Tucson, AZ, USA, 2Matrix45, LLC, Tucson, AZ, USA
1R. Ken Coit College of Pharmacy, University of Arizona, Center for Health Outcomes and Pharmacoeconomic Research, Tucson, AZ, USA, 2Matrix45, LLC, Tucson, AZ, USA
OBJECTIVES: About 1.2 million Americans are diagnosed with diabetes annually. Approximately 22.7% of diabetics use insulin. In 2025, the FDA approved Kirsty and Merilog as biosimilars of NovoLog, the reference insulin aspart. This study applied a budget impact model (BIM) to estimate the financial impact of adding Kirsty and Merilog to the insulin formulary for the treatment of adults with diabetes in a hypothetical US commercial insurance plan with one million members.
METHODS: Over a three-year period, with market splits of 90/10 (Y1), 87.5/12.5 (Y2), and 85/15 (Y3), the BIM evaluated scenarios with or without multi-dose vials and prefilled pens for Kirsty and Merilog, and the associated financial impact. An average adult body weight of 84 kg and an insulin dosage of 0.7 units/kg/day were used. Cost inputs comprised the reported wholesale acquisition cost (WAC) of the drugs. Since biosimilars have adverse event profiles similar to reference biologics, no adverse event costs were included in the cost inputs. The net budget impact per-member-per-month (PMPM) and per-member-per-year (PMPY) were estimated.
RESULTS: Kirsty and Merilog had identical WAC. The estimated three-year plan costs for NovoLog multi-dose vials and prefilled pens in the "without" scenario were $134,429,460 and $173,082,111, respectively. In the "with" scenario, this decreased to $117,498,514 and $151,282,991, with Kirsty/Merilog contributing $16,282,636 and $20,962,792, respectively. The annual net savings from the multi-dose vials range from $161,906 in 2026 to $272,098 in 2028, for a three-year total of $648,310, translating into savings of $0.05 PMPM and $0.65 PMPY. The annual net savings from prefilled pens range from $208,861 in 2026 to $351,010 in 2028, for a three-year total of $836,327, corresponding to savings of $0.07 PMPM and $0.84 PMPY.
CONCLUSIONS: The inclusion of biosimilars Kirsty and Merilog to the plan formulary yields savings over three years for both multi-dose vials and prefilled pens.
METHODS: Over a three-year period, with market splits of 90/10 (Y1), 87.5/12.5 (Y2), and 85/15 (Y3), the BIM evaluated scenarios with or without multi-dose vials and prefilled pens for Kirsty and Merilog, and the associated financial impact. An average adult body weight of 84 kg and an insulin dosage of 0.7 units/kg/day were used. Cost inputs comprised the reported wholesale acquisition cost (WAC) of the drugs. Since biosimilars have adverse event profiles similar to reference biologics, no adverse event costs were included in the cost inputs. The net budget impact per-member-per-month (PMPM) and per-member-per-year (PMPY) were estimated.
RESULTS: Kirsty and Merilog had identical WAC. The estimated three-year plan costs for NovoLog multi-dose vials and prefilled pens in the "without" scenario were $134,429,460 and $173,082,111, respectively. In the "with" scenario, this decreased to $117,498,514 and $151,282,991, with Kirsty/Merilog contributing $16,282,636 and $20,962,792, respectively. The annual net savings from the multi-dose vials range from $161,906 in 2026 to $272,098 in 2028, for a three-year total of $648,310, translating into savings of $0.05 PMPM and $0.65 PMPY. The annual net savings from prefilled pens range from $208,861 in 2026 to $351,010 in 2028, for a three-year total of $836,327, corresponding to savings of $0.07 PMPM and $0.84 PMPY.
CONCLUSIONS: The inclusion of biosimilars Kirsty and Merilog to the plan formulary yields savings over three years for both multi-dose vials and prefilled pens.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
EE116
Topic
Economic Evaluation
Topic Subcategory
Budget Impact Analysis
Disease
SDC: Diabetes/Endocrine/Metabolic Disorders (including obesity), STA: Biologics & Biosimilars