Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose: While tumor necrosis factor (TNF) blockers can be effective in treating rheumatoid arthritis (RA), the benefit of switching among TNF blockers is not clear. The objective of this study was to compare clinical outcomes and costs in US veterans who switch between adalimumab (ADA), etanercept (ETN), and infliximab (INF) to patients treated with the same TNF blocker.
Methods: The Veterans Affairs Rheumatoid Arthritis (VARA) registry is a longitudinal, observational, cohort study of US veterans with RA. It links to VA pharmacy and administrative data and documents longitudinal assessments of RA disease activity and outcomes. VARA patients initiating ADA, ETN, or INF from March 2003 (the date after which all agents were available within VA) to Sept 2010 were identified and followed until Sept 2011. A treatment course was defined as continuous TNF blocker use without a ≥90-day gap in treatment. The cost of TNF blockers with associated drug administration costs was determined for the first course initiated within the VA and compared to the second course with the same or a different TNF blocker.
Results: Data from 563 RA patients (204 ADA, 290 ETN, 69 INF) initiating TNF-blocker therapy were analyzed. All groups had a similar decrease in DAS28 during their first TNF-blocker course; however, baseline DAS28 prior to treatment and during treatment was higher during the first course for patients who eventually switched TNF blocker therapy. In the 61 patients who had 2 courses of therapy with DAS28 measurements available during both courses of treatment, there were no significant differences between mean DAS28 during the first and second TNF-blocker courses. Thus, patients who switched TNF-blocker therapies had higher DAS28 prior to and during TNF-blocker treatment compared with patients with a single TNF-blocker course or patients who had 2 courses with the same therapy interrupted by a ≥90-day gap; however, the relative change in DAS28 was the same in all groups during TNF-blocker treatment. While annualized costs were similar in all groups during the first course of therapy, these costs were significantly higher during the second course in patients who switched than for patients who restarted their initial TNF blocker (P<0.05).
Conclusion: In VARA patients receiving 2 courses of TNF-blocker therapy, improvements in DAS28 scores were not significantly different in patients treated with a different second agent than re-starting the initial agent. Patients who switched TNF blockers had higher DAS28 scores during the initial course and higher costs overall than patients who remained on the same TNF-blocker therapy. Because of potential confounding factors inherent in observational studies, more research is needed to understand reasons for switching and the effects of switching TNF blockers on overall outcomes in RA.
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Table: Comparison of patients with a single vs a second course with and without switching |
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|
|
Single course |
Second course, |
Second course, different TNF blocker (N=156) |
|||
|
|
Mean |
95% CI |
Mean |
95% CI |
Mean |
95% CI |
|
Age at start of Rx (yrs) |
63.1 |
61.9, 64.3 |
57.7 |
55.6, 59.8 |
59.0 |
57.5, 60.5 |
|
RA disease duration at Rx (yrs) |
10.6 |
9.3, 11.9 |
10.9 |
9.1, 12.7 |
9.9 |
8.4, 11.3 |
|
Male sex, n (%) |
234 (89) |
(85, 92) |
131 (92) |
(88, 97) |
142 (91) |
(87, 96) |
|
First TNF-Blocker Course |
|
|
|
|
|
|
|
Course duration (mos) |
34.1 |
30.7, 37.5 |
18.1 |
15.4, 20.9 |
18.0 |
14.9, 21.1 |
|
Annual drug and admin costs (US $ x 1000) |
13.8 |
13.4, 14.2 |
13.2 |
12.1, 14.3 |
14.2 |
13.4, 14.8 |
|
DAS28 before Rx |
4.5 |
4.3, 4.7 |
4.6 |
4.3, 4.9 |
5.3 |
5.0, 5.6 |
|
DAS28 after ≥90 days on Rx |
3.5 |
3.3, 3.7 |
3.5 |
3.3, 3.8 |
4.3 |
4.0, 4.6 |
|
Change in DAS28 on Rx |
-0.9 |
-1.2, -0.7 |
-1.1 |
-1.5, -0.6 |
-0.8 |
-1.3, -0.4 |
|
Second TNF-Blocker Course |
|
|
|
|
|
|
|
Course duration (mos) |
N/A |
N/A |
15.6 |
12.8, 18.5 |
17.7 |
14.9, 20.5 |
|
Annual drug and admin costs (US $ x 1000) |
N/A |
N/A |
12.9 |
12.1, 13.6 |
15.1 |
13.6, 16.5 |
|
DAS28 after ≥90 days on Rx |
N/A |
N/A |
3.4 |
3.1, 3.8 |
4.2 |
3.9, 4.5 |
|
Change in DAS28 1st to 2nd course |
N/A |
N/A |
-0.2 |
-0.6, 0.1 |
-0.2 |
-0.6, 0.1 |
|
CI, confidence interval; Rx, treatment; DAS28, disease activity score based on 28 joints |
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Sponsored by Immunex, a wholly owned subsidiary of Amgen and by Wyeth.
Disclosure:
G. W. Cannon,
Amgen,
2;
S. L. DuVall,
Anolinx LLC,
2,
Genentech ,
2,
Fa Hoffmann-La Roche Ltd,
2,
Amgen ,
2,
Shire PLC,
2,
Mylan Specialty LP,
2,
Merck and Co., Inc.,
2;
C. L. Hayden,
None;
L. Caplan,
None;
J. R. Curtis,
Roche/Genentech, UCB, Janssen, CORRONA, Amgen, Pfizer, BMS, Crescendo, AbbVie,
2,
Roche/Genentech, UCB, Janssen, CORRONA, Amgen, Pfizer, BMS, Crescendo, AbbVie,
5;
K. Michaud,
None;
T. R. Mikuls,
Roche/Genentech and Biogen IDEC Inc.,
2;
A. M. Reimold,
UCB,
5,
Abbvie,
2;
D. H. Collier,
Amgen Inc.,
1,
Amgen Inc.,
3;
G. Joseph,
Amgen Inc.,
3;
D. J. Harrison,
Amgen Inc.,
1,
Amgen Inc.,
3;
B. C. Sauer,
None.
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