Economic Benefit Suggested with Abatacept for RA

San Diego—Use of abatacept as first- or second-line treatment for patients with moderate-to-severe rheumatoid arthritis (RA) may have an economic benefit over other biologic disease-modifying antirheumatic drugs (DMARDs) agents, as suggested by data showing that patients treated by first- or second-line abatacept switch less frequently than patients on other biologic DMARDs.

These study results were presented during a poster session at the ACR/ARHP meeting, where investigators from Bristol-Myers Squibb used evidence from real-world observational studies to examine the frequency of switching therapies among patients with RA and the associated healthcare costs.

Using administrative data and medical and pharmacy claims from large US commercial health plan databases, the study included 2 retrospective cohort studies of adult patients with RA who initiated treatment with a biologic DMARD. Patients included in the studies had a diagnosis of RA, were >18 years of age, and had continuous eligibility for 6 months prior to the index date of initiating a biologic DMARD and 12 months post-index.

Each of the cohort studies included a population of patients newly initiated on biologic DMARD with 1 of 4 agents (ie, 1 of the 2 anti-TNF agents or abatacept) and a population of patients treated by second-line biologic DMARD. First-line biologic DMARDs were used in 9757 patients in the first study and 6320 in the second study. Second-line biologic DMARDs were used in 2174 in the first study and 1297 in the second study.

Patients in both study populations were categorized as switchers (ie, patients with a claim for a different bDMARD within 200% gap in days supply from the initial biologic DMARD) or nonswitchers (ie, patients who stayed on their index biologic DMARD in the post-index period).

According to Dr. Nadkarni, the rates of switching for the first- and second-line biologic DMARD populations in both cohorts were lower for abatacept compared to the anti-TNF agents (ie, adalimumab, etanercept, infliximab).

For patients who received an anti-TNF agent as first- and second-line biologic DMARD, 90% switched to a second anti-TNF agent.

The study then examined the cost outcomes based on switching and showed that patients who switched their first- and second-line biologic DMARD had higher healthcare costs at baseline as well as higher healthcare costs after switching compared to nonswitchers.

For example, in the first-line biologic DMARD population in the first study, the mean costs for switchers were $1416 higher per month post-switch compared with the post-index costs of nonswitchers ($3759 vs $2343, P<.05). Similarly, in the second-line biologic DMARD population in the first study, the mean costs for switchers were $1340 higher per month for post-switch compared with the post-index costs of nonswitchers ($3956 vs $2616; P<.05). Similar results were seen in the second study.

Emphasizing that these findings are consistent across 2 study cohorts, the investigators suggest that using abatacept as first- and second-line biologic DMARD treatment for RA may have an economic benefit.

Limitations of the study included the potential for data coding errors, lack of data on why people switched medications, and the omission of other biologic DMARD agents in the analysis, as well as the subcutaneous formulation of abatacept.