Implications of Non-Medical Switching in Medicare Part D: An Updated Review of the Literature

OBJECTIVES: The Inflation Reduction Act (IRA) redesigns the Part D benefit with improvements in patient affordability while also shifting more liability on plans and other stakeholders. The law requires the Centers for Medicare & Medicaid Services to set a maximum fair price (MFP) for selected Medicare Part B and D drugs. One possible consequence of the MFP process is that price reductions of selected agents may lead insurers to implement strategies (e.g. prior authorization, step-edits) aimed to steer patients towards MFP drugs and deter access to other options used to treat the same clinical condition, leading to non-medical switching (NMS). Accordingly, we performed a rapid literature review to assess the clinical, equity and economic impact of NMS to better understand the potential implications of MFP-associated NMS.

METHODS: We conducted an update to a prior systematic review evaluating the impact of NMS on outcomes. Searches were conducted in PubMed, Scopus, and CINAHL Complete databases as well as in grey literature. Articles were included in qualitative synthesis and findings were summarized.

RESULTS: Our updated review demonstrates that studies evaluating the impact of NMS are negative, positive or neutral when it comes to key outcomes. This variation is likely driven by the a number of patient level and drug effectiveness factors that affect the outcomes of treatment for different populations within various drug classes.

CONCLUSIONS: Implementation of the IRA MFP drug provisions has the potential to increase the use of strategies that lead to NMS, that could prevent seniors from accessing alternative treatments in the same therapeutic area as one of the CMS selected drugs—even if those medicines are a better fit for an individual patient. Monitoring of formularies to ensure that access to therapeutic alternatives is appropriately protected after negotiated prices go into effect is essential.