Specialty Oral Anticancer Prescription Fill Rates After Medicare Part D Cost-Sharing Changes in 2024

Abstract

This study uses data from the Symphony Health Solutions Integrated Dataverse to determine whether provisions from the Inflation Reduction Act of 2022 were associated with prescription fill changes from January 1, 2023, to December 31, 2024, among Medicare Part D beneficiaries who did not receive low-income subsidies.

Medicare beneficiaries with cancer face high out-of-pocket costs for specialty oral anticancer medications, resulting in beneficiaries frequently not filling new prescriptions.^1,2 The Inflation Reduction Act eliminated the 5% co-insurance in the Medicare Part D catastrophic coverage phase for beneficiaries without low-income subsidies (LIS) as of January 1, 2024, effectively capping annual out-of-pocket prescription costs at approximately $3250 for specialty oral anticancer medication users.³ The cost-sharing design for full-LIS beneficiaries was unchanged. This study was conducted to determine whether these provisions from the act were associated with prescription fill changes among non-LIS beneficiaries.

Methods

We used the Symphony Health Solutions’ Integrated Dataverse claims database from January 1, 2023, to December 31, 2024 (the latest data available). We identified Medicare beneficiaries with a new insurer-approved specialty oral anticancer medication prescription (ie, index prescription) for solid tumors between January 1 and October 31 in both 2023 and 2024, ensuring 60-day follow-up. We determined beneficiaries’ index prescription out-of-pocket cost, index prescription fill rate at initial presentation (initial fill rate), and index prescription fill rate within 60 days (fill rate within 60 days). Initial fill denotes prescriptions that are paid for and picked up within the typical time frame (eg, 7-10 days) allowed before the claim is canceled and the drug returned to the pharmacy’s inventory. Using a difference-in-differences (DID) design, we used logistic regression to compare changes in fill rates among non-LIS beneficiaries relative to full-LIS beneficiaries before (2023) and after (2024) the act. Additional methods, including falsification test specifications, are reported in Supplement 1. This study was deemed exempt by the University of Texas MD Anderson institutional review board and followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.

Results

There were 8479 non-LIS and 2328 full-LIS beneficiaries with an insurer-approved index specialty oral anticancer medication prescription. From January through October 2023 to January through October 2024, mean index prescription out-of-pocket costs decreased from $2728 (95% CI, $2692-$2763) to $2196 (95% CI, $2159-$2231) (P < .001) for non-LIS beneficiaries and were unchanged from $2.83 (95% CI, $2.54-$3.13) to $1.99 (95% CI, $1.78-$2.19) (P = .11) for full-LIS beneficiaries (Figure 1).

Figure 1. Out-of-Pocket Costs (Unadjusted) for New Insurer-Approved Specialty Oral Anticancer Medication Prescriptions for Solid Tumors in 2023 and 2024.

Error bars represent 95% confidence intervals. LIS indicates low-income subsidy.

^aP < .001.

The act was associated with differential increases from 2023 to 2024 in both index prescription initial fill rates (21.8% to 34.5% for non-LIS beneficiaries and 71.5% to 73.6% for full LIS beneficiaries; percentage-point DID, 10.6 [95% CI, 5.3-15.8]) and 60-day fill rates (25.3% to 40.9% for non-LIS beneficiaries and 77.8% to 79.6% for full LIS beneficiaries; percentage-point DID, 13.8 [95% CI, 9.5-18.1]) (Figure 2). As a falsification test, there was no differential change from 2023 to 2024 in either index prescription initial fill rates (percentage-point DID, −3.6 [95% CI, −8.7 to 1.4]) or 60-day fill rates (percentage-point DID, −3.3 [95% CI, −8.1 to 1.5]).

Figure 2. Initial Fill Rates and Fill Rates Within 60 Days (Adjusted) for New Insurer-Approved Specialty Oral Anticancer Medication Prescriptions for Solid Tumors in 2023 and 2024.

Error bars represent 95% confidence intervals. DID indicates difference-in-differences; LIS, low-income subsidy; pp, percentage-point change.

^aP < .001.

Discussion

From 2023 to 2024, out-of-pocket costs for a new insurer-approved specialty oral anticancer medication prescription for solid tumors declined by more than $500 for non-LIS Medicare beneficiaries while remaining unchanged for full-LIS beneficiaries after enactment of the Inflation Reduction Act’s out-of-pocket cap in 2024. This policy was associated with a nearly 14 percentage-point increase in 60-day fill rates. However, despite this policy, less than half of non-LIS beneficiaries used insurance to fill their prescription. Despite capping out-of-pocket costs, the front-loaded out-of-pocket costs (mean, $2196) for a single new specialty oral anticancer prescription may be unaffordable for many.^1,2

This study has important limitations. Prescription fills were measured using insurance claims and prescriptions filled directly through pharmaceutical companies’ patient assistance programs could not be ascertained. In addition, not all pharmacies are included; however, prescriptions were insurer-approved, and it is unlikely that many patients would subsequently fill prescriptions at different pharmacies. Last, unobserved differences between full-LIS and non-LIS beneficiaries concurrent with the act change could bias the estimates, although no evidence of differential prepolicy trends was found. While this study suggests that an annual cap alone may not improve specialty oral anticancer medication fills for the majority of non-LIS Medicare beneficiaries, future research should study how the act’s 2025 out-of-pocket cap of $2000, combined with the opt-in Medicare Prescription Payment Plan, which allows beneficiaries to spread out-of-pocket costs across monthly payments, affects medication access.^4,5,6

Supplement 1.

eMethods

Supplement 2.

Data Sharing Statement