Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Does Sequence Matter When Switching from One AntiTumor Necrosis Factor Agent to Another?

Baser3,  O., Roy1,  S., Akin2,  C., Cifaldi1,  M. A.

Abbott Laboratories, Abbott Park, IL
Brigham and Women's Hospital, Boston, MA
University of Michigan, Ann Arbor, MI

Background:

A significant proportion of patients with rheumatoid arthritis (RA) switch from one anti–tumor necrosis factor (anti-TNF) agent to another. This study examines patient characteristics, costs, and outcomes of switching from one anti-TNF to another. Predictors of switching between anti-TNFs are also examined.

Methods:

Continuously eligible adult patients in a large commercial administrative claims database with confirmed diagnoses of RA between January 2002 and December 2008 were included if they had initiated new anti-TNF treatment after a 12-month biologic-free period. Disease severity was estimated using a composite Severity Index for Rheumatoid Arthritis (SIFRA), a measure validated for administrative databases. Costs and outcomes were compared between groups 12 months after the switch, after adjusting for baseline differences in patient, disease, and prescriber characteristics through a propensity score-matching technique. Cox regression was used to determine the predictors of time to switch of biologic treatment.

Results:

There were 1,567 patients in the study who switched to a second anti-TNF. Of these patients, 48% (n=751) switched to ADA, 19% (n=294) to IFX, and 33% (n=522) to ETN. Patients who were younger (HR=0.40), used methotrexate (HR=0.76), or other DMARDs (e.g. SSZ, HCQ and Gold) at baseline (HR=0.73), and had a low SIFRA severity index (HR=0.85) experienced a shorter time to switching to a second anti-TNF. Patients who started with IFX or ETN switched to a second anti-TNF sooner than those who started on ADA (HR=0.86 for ETN and 0.85 for IFX vs. ADA). Patients switching from ETN to IFX instead of to ADA had more severe disease (p=0.002), had a greater comorbidity burden (p=0.002), were more likely to use MTX (p=0.0259), and were more likely to have had dose escalation prior to switch. Patients switching from ADA to IFX had a greater comorbidity burden compared with those who switched to ETN. Among switchers from IFX, slightly older patients with higher rates of respiratory infections were switched to ADA, compared with ETN. After adjusting for baseline differences, RA-related total annual health care costs were significantly lower for switches between the subcutaneously injected anti-TNFs (ETN-ADA, p<0.0001 both ways) compared with switches to their infusion counterpart (IFX). Among all possible anti-TNF sequences, RA-related total costs, as well as disease severity were lowest one year after a switch to ADA irrespective of which anti-TNF patients were switched from (table).

Conclusions:

The timing and outcomes of switching were observed to be different based on sequence of anti-TNFs used. Relative to ADA, patients switched sooner to a second anti-TNF if they had started on IFX or ETN. Both cost and disease severity outcomes appear to be better for switches to ADA compared with switches to IFX or to ETN.

Adjusted RA-Related Costs and Disease Severity Outcomes 1 Year After Switch

 ETN to IFXETN to ADAP- ValueIFX to ETNIFX to ADAP-ValueADA to ETNADA to IFXP- Value
Total RA-related cost$19,523$15,632<0.0001$15,324$14,9860.574$18,652$24,867<0.0001
SIFRA5.154.65<0.00015.014.710.00014.744.760.805

To cite this abstract, please use the following information:
Baser, O., Roy, S., Akin, C., Cifaldi, M. A.; Does Sequence Matter When Switching from One AntiTumor Necrosis Factor Agent to Another? [abstract]. Arthritis Rheum 2010;62 Suppl 10 :307
DOI: 10.1002/art.28076

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