In pregnant women with arthritis, discontinuing tumor necrosis factor inhibitors prior to gestational week 20 seems feasible without an increased risk of disease worsening, particularly in those with well-controlled disease, according to authors of a recent analysis of a prospective cohort study.
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Stopping tumor necrosis factor inhibitor (TNFi) treatment at that point in the second trimester was not linked to any clinically important worsening of patient-reported outcomes later in pregnancy for women with rheumatoid arthritis (RA) or juvenile idiopathic arthritis (JIA), the researchers said.
However, continuing a TNFi past gestational week 20 may also be warranted for some patients, according to the researchers, led by Frauke Förger, MD, of the University of Bern (Switzerland).
“In case of active disease, the continuation of TNF inhibitors beyond gestational week 20 seems reasonable from the standpoint of improved disease activity in the third trimester, which may in turn lead to improved pregnancy outcomes,” Dr. Förger and her coinvestigators wrote in Arthritis & Rheumatology.
These findings stand in contrast to those of another recent study, in which stopping a TNF inhibitor after a positive pregnancy test was linked to disease flares in women with RA, according to the authors.
“The timing of drug discontinuation during pregnancy may be of importance,” they said in their report.
Beyond these studies, there are very limited data on the effects of discontinuing TNF inhibitors in pregnant women with rheumatoid arthritis, and “a lack of any data” in pregnant women with JIA, they said.
The current investigation by Dr. Förger and her colleagues included 490 pregnant women in the United States or Canada who were enrolled in the Organization of Teratology Information Specialists (OTIS) Autoimmune Diseases in Pregnancy Project, a prospective cohort study. Of those women, 397 had RA and 93 had JIA.
About one-quarter of the women (122, or 24.9%) discontinued TNF inhibitor therapy prior to gestational week 20, while 41% continued on TNF inhibitors beyond that point, and 34.1% did not use a TNF inhibitor in pregnancy.
For those women who discontinued TNF inhibitors before gestational week 20, scores on the Patient Activity Scale (PAS) were stable over time, Dr. Förger and her colleagues reported.
Women who continued TNF inhibitor treatment past gestational week 20 had improved PAS scores in the third trimester, according to results of a univariate analysis (P = .02). However, the improvement appeared to be attenuated after adjustment for factors including race, smoking, use of prednisone or disease-modifying antirheumatic drugs, and gestational age, the investigators said.
They were unable to analyze the effects of ongoing TNFi treatment or discontinuation on patients with JIA separately because of the limited number of such patients in each group.
Another limitation of the study is that a high proportion of women – nearly three-quarters – had low disease activity at the start of pregnancy, according to the investigators, who said that group of women might expect some degree of improvement in the third trimester with or without TNF inhibitor discontinuation.
“In this context, the ameliorating effect of pregnancy on RA and JIA, which is most pronounced in the third trimester, may play a role,” they explained.
A certain proportion of women choose to discontinue certain arthritis treatments during pregnancy because of concerns that the medication may lead to fetal harm, but that may be changing, the investigators noted in their report.
“In recent years, more patients requiring treatment have been continuing on effective TNF inhibitors beyond conception as the available data on the safety of TNF inhibitors during pregnancy has increased,” they wrote.
Dr. Förger and her coauthors reported no financial disclosures or conflicts of interest. Financial support for the OTIS Collaborative Research Group comes from industry sources including AbbVie, Bristol-Myers Squibb, Celgene, Hoffman La Roche-Genentech, Janssen, Pfizer, Regeneron, Sandoz, and UCB, among others.
SOURCE: Förger F et al. Arthritis Rheumatol. 2019 Jan 21. doi: 10.1002/art.40821