Estimated Changes in Insulin Prices and Discounts After Entry of New Insulin Products, 2012-2019

IMPORTANCE: Despite the political salience of insulin prices, no study to date has quantified trends in insulin prices that account for manufacturer discounts (net prices). OBJECTIVE: To describe trends in insulin list prices and net prices faced by payers from 2012 to 2019 and estimate changes in net prices after the 2015 to 2017 entry of new insulin products. DESIGN, SETTING, AND PARTICIPANTS: This longitudinal study included an analysis of Medicare, Medicaid, and SSR Health drug pricing data from January 1, 2012, to December 31, 2019. Data analyses were performed from June 1, 2022, to October 31, 2022. EXPOSURES: US sales of insulin products. MAIN OUTCOMES AND MEASURES: Net prices faced by payers were estimated for insulin products as list prices minus manufacturer discounts negotiated in commercial and Medicare Part D markets (ie, commercial discounts). Trends in net prices were evaluated before and after the entry of new insulin products. RESULTS: Net prices of long-acting insulin products increased at an annual rate of 23.6% from 2012 to 2014 but decreased at an annual rate of 8.3% after the introduction of insulin glargine (Toujeo and Basaglar) and degludec (Tresiba) in 2015. Net prices of short-acting insulin increased at an annual rate of 5.6% from 2012 to 2017 but then decreased from 2018 to 2019 after the introduction of insulin aspart (Fiasp) and lispro (Admelog). For human insulin products, which did not experience entry of new products, net prices increased at an annual rate of 9.2% from 2012 to 2019. From 2012 to 2019, commercial discounts increased from 22.7% to 64.8% for long-acting insulin products, from 37.9% to 66.1% for short-acting insulin products, and from 54.9% to 63.1% for human insulin products. CONCLUSIONS AND RELEVANCE: In this longitudinal study of US insulin products, results suggest that insulin prices substantially increased from 2012 to 2015, even after accounting for discounts. The introduction of new insulin products was followed by substantial discounting practices that lowered net prices faced by payers.