Background 

For Medicare beneficiaries, high-cost infused therapies may be covered under Medicare Part B or Part D, depending on coverage and how and where treatment is delivered. These coverage pathways can differ in payment, pharmacy or provider involvement, and beneficiary cost sharing. 

Part B generally covers drugs administered in physician offices or outpatient settings, while Part D may cover certain therapies dispensed through pharmacies. Beneficiary costs under Part B may also vary based on supplemental coverage, including Medigap or Medicaid, while Part D cost sharing varies by benefit phase and low-income subsidy (LIS) status. 

Understanding utilization across benefits can help stakeholders assess access pathways, patient populations, and potential areas for ongoing monitoring. 

Most Utilization Occurs in Part B, But Part D Plays a Growing Role 

Avalere Health analyzed Medicare FFS claims for a high-cost infused therapy in the ophthalmology space and identified nearly 2,500 beneficiaries with observed use in 2020 or 2021. 

Given the therapy was an infused product, as expected, most beneficiaries received treatment through Part B only during the study period. However, Part D use and transitions between benefits were observed: 

• Nearly 10% of beneficiaries (~200) had at least one claim for the therapy under the Part D benefit. 

• Forty-three percent of beneficiaries with a Part D claim were LIS beneficiaries. For comparison, 17% of beneficiaries with a Part B claim were dually eligible for Medicare and Medicaid. 

• The average time between observed administrations or fills was 27 days in Part B and 23 days in Part D. 

• Among the small number of beneficiaries (N<30) who transitioned between benefits, average time between observed administrations or fills was longer for Part B-to-Part D transitions (38 days) than for Part D-to-Part B transitions (20 days). 

Stakeholder Considerations 

Observed differences in Part B and Part D use may reflect coverage rules, site-of-care practices, pharmacy arrangements, supplemental coverage, and patient needs. Stakeholders can use claims data to monitor benefit pathways, identify populations with distinct coverage experiences, and assess whether transitions between benefits are associated with changes in treatment timing. 

For therapies covered under Part D, the Medicare Prescription Payment Plan allows beneficiaries to spread out-of-pocket costs across the remaining months of the plan year. Manufacturers, plans, pharmacies, and providers may consider how awareness of the program, enrollment timing, and beneficiary communications could affect patients’ experience of Part D cost sharing. 

Methods 

This analysis utilized the 100% Medicare fee-for-service (FFS) claims, accessed by Avalere via a research collaboration with Inovalon, Inc. and governed by a research-focused CMS Data Use Agreement (DUA).  Avalere Health analyzed claims from calendar years 2020 and 2021. The therapy was identified using applicable medical and pharmacy claim codes. Beneficiaries were assessed by benefit pathway, LIS status, and timing of observed administrations or prescription fills. 

Longitudinal analyses included beneficiaries continuously enrolled in Medicare fee-for-service during the study period and tracked monthly use across Part B and Part D. Results with fewer than 11 beneficiaries were suppressed in accordance with Centers for Medicare & Medicaid Services data-use requirements.