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.


Rate of Serious Infections in RA Patients Who Subsequently Receive Other Biologic Therapies after Discontinuing Rituximab Treatment.

Genovese8,  Mark C., Breedveld4,  Ferdinand, Emery2,  Paul, Cohen6,  Stanley B., Keystone9,  Ed C., Matteson5,  Eric L., Burke7,  Laura

Biogen Idec
Chapel Allerton Hospital, Leeds, United Kingdom
Genentech
Leiden Univ
Mayo Clinic, Rochester, MN
Rheumatology Associates, Dallas, TX
Roche
Stanford Univ, Sunnyvale, CA
University of Toronto, Toronto, ON, Canada

Purpose:

Rituximab (RTX) selectively targets CD20+ B-cells and is approved for treatment of RA patients (pts) who had an inadequate response to >=1 TNF-inhibitor(s) (TNFi). The pharmacodynamic effect of RTX may be long lasting. The safety of treatment with other biologic disease-modifying antirheumatic drugs (BDMARDs) during this period of peripheral B-cell depletion in pts who have discontinued RTX is an important clinical question. The purpose of this analysis is to describe the rate of serious infection events (SIEs) in pts treated with RTX, who subsequently received a BDMARD.

Methods:

Pts with moderately-to-severely active RA who received RTX + methotrexate within an international clinical trial program were included. Following completion or withdrawal from their studies, pts entered safety follow-up (SFU) and peripheral B-cell counts were monitored for >=48 wks. During SFU, pts were permitted to receive BDMARDs. All SIEs, defined as serious adverse events or infections that required IV antibiotics, were collected.

Results:

As of Sept 2009, 3189 RA pts had received >=1 course of RTX providing 9365 pt-yrs of follow-up (SIE rate / 100 pt-yrs: 4.34 [95% CI: 3.93, 4.78]). Of pts who entered SFU, 283 pts were subsequently treated with BDMARD (median time 8.5 mo [range: 0.1–52] after last RTX infusion). 87 (30.7%) pts received their BDMARD < 6 mo of their last RTX infusion. 230 of the 283 pts received TNFi after RTX. Median follow-up time after receipt of the subsequent BDMARD was 11 mo (7—17). At the time of receiving further BDMARD treatment, 83% had peripheral B-cell counts below lower limit of normal (LLN) (<80 cells/mL). During treatment with RTX and prior to receipt of the BDMARD, the 283 pts had 6.01 SIEs / 100 pt-yrs (Table). Following initiation of BDMARD, the SIE rate was 4.97 / 100 pt-yrs. Median time to SIE after initiating BDMARD was 11 mo (range: 2—21). In 43 pts who received abatacept (ABA) as their 1st subsequent BDMARD post RTX, there was 1 SIE before and 1 after receiving ABA (97.7 total pt-yrs). Overall, the infections were variable and typical for RA pts, with no opportunistic or fatal infections. In subgroup analysis of 174 patients with CD19+ counts <20 cells/ mL at the time of receipt of their next BDMARD, SIE rate / 100 pt-yrs was 6.28 (3.79, 10.42). In pts who received BDMARD <6 mo (n= 87) or >=6 mo (n= 196) post RTX, SIE rates were 5.04 (2.26, 11.22) and 4.94 (2.66, 9.18), respectively.

Conclusion:

In this updated analysis, the use of other BDMARDS in RA pts previously treated with RTX was not associated with an increase in the rate of serious infections. The rate of serious infections is consistent with rates seen in long-term safety analyses.

To cite this abstract, please use the following information:
Genovese, Mark C., Breedveld, Ferdinand, Emery, Paul, Cohen, Stanley B., Keystone, Ed C., Matteson, Eric L., et al; Rate of Serious Infections in RA Patients Who Subsequently Receive Other Biologic Therapies after Discontinuing Rituximab Treatment. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :403
DOI: 10.1002/art.28172

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