Association of Generic Competition With Price Decreases in Physician-Administered Drugs and Estimated Price Decreases for Biosimilar Competition.

Importance: Price decreases of biologic and biosimilar products in Medicare Part B have been minimal, even with biosimilar competition. Medicare reimburses clinicians for biologics and biosimilars differently than for brand-name and generic drugs, which has generated greater price reductions. Objective: To characterize the nature of price competition among brand-name and generic drugs under Medicare Part B and to estimate the cost savings to the program of subjecting biologic and biosimilar therapies to a similar price competition. Design, Setting, and Participants: This cohort study analyzed all brand-name drugs and their approved generic versions as well as biologics and biosimilars that were reimbursed under Medicare Part B from quarter 1 of 2005 to quarter 2 of 2021. Two separate data sets were created: brand-name and generic drugs as well as biologics and biosimilars data sets. Brand-name products with generic versions that were introduced before 2005 were excluded, and so were vaccines. Exposures: Number of generic and biosimilar competitors over time. Main Outcomes and Measures: Price change as a percentage of the brand-name drug or biologic price in the quarter before generic or biosimilar competition. Price change was modeled using a linear, fixed-effects time series regression, with the number of generic or biosimilar competitors as the main covariate. Time was expressed as the number of quarters since the first generic or biosimilar competitor entered the market. Savings were estimated by projecting the regression model of brand-name and generic drug competition to observed biologic and biosimilar competition and by applying the estimated price reduction to actual Medicare spending for those products from 2015 to 2019. Results: Of the 988 Healthcare Common Procedure Coding System codes identified, 50 (5.0%) met the inclusion criteria for the brand-name and generic drug data set and 28 (2.8%) met the criteria for the biologic and biosimilar data set. The first generic competitor was associated with reduced drug prices by 17.0%, the second competitor with a 39.5% decrease, the third competitor with a 52.5% decrease, and the fourth and more competitors with a 70.2% decrease (price decline was measured from brand-name drug price before the first generic competitor rather than from price established with fewer competitors). If biologics and biosimilars were subject to the same Medicare reimbursement framework as brand-name and generic drugs, Medicare spending on these products was estimated to have been 26.6% lower ($1.6 billion) from 2015 to 2019. Conclusions and Relevance: This study found minimal uptake of biosimilars and limited price reductions for biologics and biosimilars under the current Medicare Part B reimbursement policy. Adopting the bundled biosimilar reimbursement structure for biologic and biosimilar therapies may be associated with substantial savings and encourage greater biosimilar market entry.