Real-World Costs of Biologic Agents for Rheumatoid Arthritis

San Francisco—When assessing the treatment costs of biologic agents used to treat patients with rheumatoid arthritis (RA), health plans should calculate reimbursed dollars plus patient copayments rather than wholesale acquisitions costs (WACs) to get the actual cost of these agents.

This is the conclusion of a study presented in a poster session at the AMCP meeting. The poster was titled Calculation of Annual Biologic Treatment Costs in Rheumatoid Arthritis—A Comparison of Methods and Relationship to Adherence.

This study was undertaken to better understand the real-world costs of biologic agents used to treat RA by comparing annual WAC-based cost calculations versus actual reimbursed costs, and by looking at how adherence to prescribed treatment regimens affects costs.

Using data from the Thomson Reuters MarketScan^® database, the study included 10,541 RA patients treated with adalimumab (ADA) (n=3417), etanercept (ETA) (n=4898), and infliximab (IFX) (n=2226). All patients included in the analysis were at least 18 years of age, had ≥2 ETA and ADA or ≥4 IFX claims submitted between January 2003, and June 2008, were continuously enrolled for 12 months prior and ≥12 months after index date, had ≥2 RA claims, and had no gap in therapy for ≥180 days.

Patients were not included if they had submitted any biologic claims 6 months prior to index date, had switched therapy during the 12-month follow-up period, or had a diagnosis of other inflammatory diseases.

The study used recommended prescribing regimens for each biologic to calculate costs and assess treatment adherence. The prescribed regimen for ADA is administration at 40 mg every other week with an increase in frequency to 40 mg every week if needed.

The prescribed regimen for ETA is administration at 50 mg every week, and for IFX, administration at weeks 0, 2, 6, and every 4 to 8 weeks thereafter.

Treatment adherence was defined as gaps in therapy in excess of days supply of ETA and ADA, and the number of days between infusion dates after the third infusion for consecutive IFX claims beyond the expected 56 days.

Costs were calculated using cumulative dose multiplied by the WAC, as well as amounts paid by the healthcare plan and patient. Drug costs were based on April 2010 WAC.

The study found that WAC-based calculations were significantly higher than the healthcare plan reimbursed amounts. The mean biologic drug cost of ADA, ETA, and IFX using WAC-based calculations were $21,394, $19,392, and $22,338, respectively. The costs for these same drugs based on the healthcare plan reimbursement amount were $17,167, $15,586, and $19,054, respectively; costs of patient copayments were $354, $337, and $84, respectively.

The investigators suggest that the lower costs of ADA and ETA compared to IFX, despite the more frequent dosing of ADA and ETA, may be partially due to underutilization of ADA and ETA treatment. The study found that the average gap in excess of days supply over 12 months of follow-up was 9.8 days for ADA-treated patients and 11.5 days for ETA-treated patients, with no gap in therapy for IFX-treated patients.

In addition, the study found that the gap in therapy for the first 5 fills was >7 days for >20% of patients treated with ADA and ETA, whereas patients undergoing IFX treatment were within 2 days of the recommended prescribing regimen over the first 5 maintenance infusions.

This study was supported by Janssen Scientific Affairs, LLC.