Avalere analyzed adherence to a combination oral and intravenous (IV) kidney cancer treatment regimen among Medicare fee-for-service (FFS) and Medicare Advantage (MA) patients enrolled in Medicare Part D. The analysis stratified patients based on whether they qualified for the Part D low-income subsidy (LIS). Qualifying patients receive cost-sharing assistance for the oral therapy. Because most of these patients are dually eligible for Medicaid, they also pay less in coinsurance for the IV therapy than patients who do not qualify for the LIS. Avalere found that LIS and non-LIS patients adhered to the oral treatment at similar rates, whereas LIS patients, despite their lower cost burden, adhered to the IV treatment at lower rates than non-LIS patients. This disparate rate of adherence may signal the presence of non-financial risk factors (e.g., lack of access to transportation or childcare) affecting LIS patients’ utilization of the IV therapy, resulting in potential health outcome disparities.

Analysis

Avalere’s analysis included Medicare FFS and MA patients who in 2019 were enrolled in Medicare Part D and were prescribed an oral/IV combination regimen to treat kidney cancer. The analysis used a metric called proportion of days covered (PDC)—a metric of the rate at which a prescription is refilled—to measure adherence to the oral therapy, and measured adherence to the prescribed IV schedule relative to the oral PDC metric: specifically, if a patient record showed an IV administration within each period covered by one oral fill—as clinical dosing guidelines specify—then that patient was considered adherent to the prescribed IV utilization schedule. Patients were considered adherent if the PDC was greater than 80%.

 Adherence to the Oral Component of the Combination Regimen

Results showed that LIS and non-LIS patients adhered to the oral component of the combination regimen at similar rates, with median PDCs of 72.4% and 72.1%, respectively. Median monthly out-of-pocket (OOP) costs, however, varied between groups: non-LIS patients paid $283 in FFS or $272 in MA, whereas LIS patients paid little to nothing in cost sharing for the oral therapy.

To investigate further how OOP burden may be associated with reduced adherence, Avalere stratified the non-LIS patients by whether they were enrolled in an employer group waiver plan (EGWP). This stratification isolated financial variables by enabling comparison of patients with similar demographic profiles who may experience different financial burden associated with treatment (i.e., because EGWP patients typically incur lower OOP costs because their plans have lower deductibles and fixed copays through supplemental benefits). Results showed a higher median proportion of days covered among EGWP patients (75.2%) than non-EGWP patients (71.7%), suggesting that cost may be one component of differential adherence.

Adherence to the IV Therapy Schedule

Results also showed that LIS and non-LIS patients differed in their rates of adherence to IV treatment schedules, as measured relative to their PDC metric for oral adherence. A higher percentage of LIS patients (76.8%) adhered less to IV treatment compared to non-LIS patients (83.2%). Avalere also stratified the non-LIS population by enrollment in an EGWP plan, finding that 81.3% of EGWP beneficiaries adhered to schedule compared to 82.1% of non-EGWP beneficiaries. Non-LIS patients in FFS paid a median monthly OOP cost of $652 for IV treatment, whereas those in MA paid a lower median monthly OOP cost of $558. LIS patients, most of whom are also eligible for Medicaid, paid lower OOP costs because of cost-sharing assistance via Medicaid’s medical benefit. Despite this reduced financial burden, these patients adhered to the IV treatment schedule at a lower rate than non-LIS beneficiaries, signaling the potential influence of non-financial factors such as social determinants of health (SDOH) that may pose barriers to access.

Discussion

Findings show that although patient OOP cost may impact medication adherence, other variables including social risk factors may impact adherence as well. Adherence barriers may also vary across treatments based on variables such as route of administration and coverage under the medical versus the pharmacy benefit.

LIS and non-LIS patients adhered to the oral treatment regimen at similar rates, despite differing OOP cost burdens. Had cost been the key adherence barrier, LIS patients may have adhered to the oral treatment regimen at higher rates. The similar adherence rates between LIS and non-LIS patients may suggest that  SDOH factors may have affected oral adherence among both patient cohorts. Conversely, EGWP patients paid lower OOP costs and adhered to the oral treatment regimen at higher rates than non-EGWP patients, signaling differences in adherence between these two groups related more directly to differences in OOP costs.

This analysis revealed a pattern of adherence challenges for both oral and IV regimens among LIS patients, suggesting that non-financial social risk factors may create barriers for low-income patients seeking treatment access. Such social risk factors may include:

• Health literacy challenges
• Lack of proximity to providers
• Difficulty identifying provider sites
• Lack of transportation to provider sites
• Lack of time for IV infusion appointments

As manufacturers plan for commercialization, especially for combination regimens, they should develop comprehensive patient support and access strategies, accounting for all factors likely to influence patient choice and access to effective treatment.

Funding for the research was provided by Janssen Pharmaceuticals. Avalere Health retained full editorial control.

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Methodology

This analysis used 100% Medicare FFS and Part D prescription drug event (PDE) data, accessed via a research collaboration with Inovalon under a Centers for Medicare & Medicaid (CMS) data use agreement. It also leveraged Inovalon’s MORE² registry to access a convenience sample of payer-sourced claims for MA patients. Avalere identified Medicare FFS and MA patients who, in 2019, were enrolled in Medicare Part D and were prescribed an oral/IV combination regimen to treat kidney cancer. The analysis included all such patients who submitted both a Part D claim for the oral drug and a Part B claim for the IV drug within a 30-day period.

To measure adherence to the oral therapy, Avalere used PDE data to calculate PDC, a measure of medication adherence based on CMS’s method of calculating its Part D star ratings measure. Avalere divided the number of days within the measurement period for which patient records showed coverage with treatment, by the total number of days in the measurement period​. Treatment coverage period was determined based on service date and days of drug fill supply​. The analysis adjusted for overlapping prescription fills such that each fill began when coverage for the preceding fill ended​. To calculate OOP costs for the oral therapy, Avalere used the patient pay amount reported on the PDE.

Avalere used Medicare Part B claims and a sample of MA claims to measure utilization and OOP costs for the IV therapy. A patient was considered adherent to the IV regimen if an IV administration for that patient was logged within the expected timeframe of each oral fill per clinical dosing guidelines. For dually eligible beneficiaries, Avalere calculated coinsurance for the IV therapy before application of any liability reduction via Medicaid.