RESEARCH - TNF antagonists not linked to major malignant lymphoma risk in RA patients

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TNF Antagonists Not Linked to Major Malignant Lymphoma Risk in RA Patients

NEW YORK (Reuters Health) Jun 02 - Anti-tumor necrosis factor (TNF)

therapy does not markedly increase the risk of malignant lymphoma in

patients with rheumatoid arthritis, according to the results of a

Swedish study. This study is one of the largest to-date to assess

effects of anti-TNF therapy in rheumatoid arthritis patients.

Dr. J. Askling of the Karolinska University Hospital and

co-investigators also found that the small increased risk of lymphoma

that was detected among patients who started anti-TNF therapy occurred

in the early stages of treatment. Although the reason or reasons for

this are not clear, the researchers offered several possibilities.

One factor is possible channeling bias, because patients who started

on anti-TNF drugs when they first became available were by some

measures already at higher risk.

Another possibility is that the finding " reflects a limited ability of

our study to adjust fully for accrued disease severity, " they report

in the May issue of the ls of the Rheumatic Diseases.

In any case, they note, the study " points to the need for protracted

follow-up of the safety profile of biological agents. "

Based on data from two large Swedish registries and other databases,

the investigators assembled a national rheumatoid arthritis cohort of

67,743 patients. This cohort reflected the majority of Swedish

rheumatoid arthritis patients alive in 1998.

Of these subjects, 6604 started anti-TNF therapy between 1998 and

2006. The most common initial anti-TNF agent was infliximab (51%),

followed by etanercept (34%) and adalimumab (14%). More than one

anti-TNF drug was used by 25% of patients. A comparator cohort of

471,024 subjects from the general population was also assembled.

A total of 26 patients on anti-TNF therapy developed malignant

lymphomas during 26,981 person-years of follow-up. The relative risk

of malignant lymphoma among anti-TNF-treated rheumatoid arthritis

patients was 1.35 compared with anti-TNF-nave patients and 2.72

compared with the controls. The former increase was statistically

nonsignificant and was accounted for entirely by patients who began

anti-TNF treatment before 2002.

Ann Rheum Dis 2009;68:648-653.

http://www.medscape.com/viewarticle/703758

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