The Centers for Medicare and Medicaid Services (CMS) established guidance for Medicare Part B step therapy effective in 2019. When a new step therapy edit is implemented for a Medicare Part B drug, patients already taking that medication are able to maintain their current treatment, even when the beneficiary’s existing therapy becomes non-preferred on their Medicare plan. The beneficiary will not need to change medications or obtain additional prior authorizations to remain on their current, non-preferred medication, assuming there is confirmation of the existing treatment within the last 365 days.

Since this change, Medicare Advantage programs have amended their step therapy programs to include more biosimilars as preferred options. Drug categories with more available biosimilars on the market have been prone to extending and enhancing their step therapy coverage as more products become available. For drug categories lacking extensive biosimilar options, there are significantly less step therapy edits in place; however, policies are subject to change. This focus on biosimilars can provide a more cost-effective alternative to a reference biologic, while maintaining the same efficacy. While biosimilars are increasing in popularity and market availability is expanding, there has also been a corresponding increase in the implementation of step therapy edits for these products in Medicare plans.

For example, in 2023, 54% of Medicare Advantage enrollees were in plans that required step therapy for ten commonly used rheumatoid arthritis drugs covered under Part B.¹ According to UPMC Health Plan, patients beginning a new treatment may be required to start with a less expensive medication, such as a biosimilar of infliximab (e.g., Inflectra), before advancing to reference biologics like Remicade.

This model is associated with a greater probability of prescribing preferred therapy for the first administration. How will this impact future biosimilar launches?

1. Frazier, L; Tripp, A, et al. MA Plans Increase Use of Step Therapy for Part B Drugs. Avalere. Published May 24, 2024. https://avalere.com/insights/ma-plans-increase-use-of-step-therapy-for-part-b-drugs