Costs of Dose Escalation in RA Likely to Be Offset by Savings From Infliximab Biosimilars

Using a biosimilar can produce substantial cost savings in patients who are receiving infliximab therapy for inflammatory diseases like rheumatoid arthritis (RA), but dose escalations, which are frequent for those who use infliximab, can increase the cost of therapy, even with a biosimilar.

Recently, in a paper appearing this month in Arthritis Research and Therapy, investigators studied the frequency of dose escalation with biosimilar infliximab versus using an alternative agent—like golimumab—that is subject to fewer dose escalations.

In the study, the authors assembled 2 cohorts of Medicare beneficiaries with RA who were starting treatment with either infliximab (n = 5147) or intravenous golimumab (n = 2843). They used CMS fee-for-service Medicare data from 2012 to 2016 to compare dose escalation (defined as a dose increase of 100 mg or more for infliximab or 50 mg or more for golimumab, or increased frequency of dosing), persistence, and the cost to Medicare.

A hypothetical modeling scenario was used to compare dose-escalated infliximab versus golimumab using Medicare-approved amounts in the first quarter of 2016 to evaluate the extent to which dose escalation would be needed before it offset higher Medicare-approved payment a mounts for golimumab, and the model took into account potential discounts for biosimilar infliximab.

They found that dose escalation occurred in 49% of patients receiving infliximab, versus just 5% of those receiving golimumab. Physician ownership of infusion centers was associated with an increased likelihood that infliximab doses would be increased (odds ratio, 1.25; 95% CI, 1.09-1.44).

The mean costs paid by Medicare over the initial 18 months of treatment were higher for golimumab ($28,146, standard deviation [SD]; $16,030) than for infliximab ($21,216; SD, $15,819). Among patients who persisted with treatment through 18 months, least square mean costs were $43,940 for golimumab and $34,671 for infliximab.

In the modeling scenario used to evaluate the level of dosing that would be required to offset higher costs of golimumab use, all dosing frequencies of infliximab at doses of either 3 mg/kg or 5 mg/kg yielded lower annual costs than golimumab. At 10 mg/kg every 6 weeks, infliximab became more costly than golimumab unless discounts of 30% of higher were applied. At 10 mg/kg every 4 weeks, discounts of 50% of greater would be necessary. Given the 21% average sales price discount of the biosimilar Inflectra in 2019, even a dose of infliximab at 8 mg/kg every 6 weeks would be cost-neutral or cost-saving versus golimumab.

The authors conclude that, “costs associated with dose escalating infliximab to 10 mg/kg every 4 or 6 weeks are substantial and likely offset even appreciable dose savings associated with biosimilars,” and, in patients who require such escalations, using an alternative therapy is likely to be less expensive while achieving similar outcomes. For all other lower doses, costs associated with dose escalation are likely to be offset by biosimilar savings.

Reference

Curtis JR, Xie F, Kay J, Kallich JD. Will savings from biosimilars offset increased costs related to dose escalation? A comparison of infliximab and golimumab for rheumatoid arthritis [published online December 12, 2019]. Arthritis Res Ther. doi: 10.1186/s13075-019-2022-8.