Spending on biologic drugs is a significant driver of drug expenditures for payers in private health plans. Biologic disease-modifying antirheumatic drugs (DMARDs) are some of the most effective and costly treatments in a physician's arsenal. Understanding the total annual expenditure, the average cost per prescription, and the impact of cost-sharing is important for drug benefit managers.
To assess drug utilization, expenditures, out-of-pocket (OOP) cost, and price trends of biologic DMARDs in patients with rheumatoid arthritis (RA) in a large managed care organization.
We conducted a retrospective database analysis of pharmacy claims data from January 2004 to December 2013 using the Optum Clinformatics Data Mart database, which covers 13.3 million lives. Pharmacy claims for 40,373 patients with RA were identified during the study period. In all, 9 biologic DMARDs approved for the treatment of RA, including infliximab, etanercept, adalimumab, certoizumab, golimumab, tocilizumab, anakinra, abatacept, and rituximab, and 1 nonbiologic oral, small molecule-targeted synthetic drug, tofacitinib, were included in this study. Descriptive statistics were used to analyze the total annual number of prescriptions, the total annual expenditures, the average annual cost per drug (a proxy of drug price), and the average OOP cost (copay plus deductible and coinsurance). All measurements were also stratified by study drugs and by insurance type.
Of the 40,373 patients with RA included in the study, approximately 76% were female (mean age, 55 years at diagnosis). Approximately 77% of the patients were white, and almost 48% lived in the South or Midwest region of the United States. Approximately 62% of patients had a point of service insurance plan. Expenditures on biologic DMARDs increased from $166 million in 2004 to $243 million in 2013, and the number of prescriptions and refills increased from 59,960 in 2004 to 105,295 in 2013. Prescriptions for biologic DMARDs increased more than 20% per patient from 2004 to 2013. The average cost per prescription remained relatively unchanged, at approximately $2300 per prescription, but the OOP expenditures increased from $36 (2.5%) per prescription to $128 (7%) during the study period. The OOP expenditures increased the most in HMO plans and in plans categorized as other (284% and 388%, respectively).
Spending on biologic DMARDs has been primarily driven by an increase in prescribing rates, as the average amount reimbursed per prescription remained relatively unchanged over time, despite a regular annual increase to the average wholesale acquisition cost of 2% to 10%. The OOP burden for patients has increased, but this does not appear to have limited the use of biologic DMARDs. The entrance of new biologic and nonbiologic DMARDs into the market in the past few years is eroding the market share for several established drugs, and may lead to different results, warranting a study of new trends.