TY - JOUR T1 - Do Tumor Necrosis Factor Inhibitors Cause Malformations in Humans? JF - The Journal of Rheumatology JO - J Rheumatol SP - 465 LP - 466 DO - 10.3899/jrheum.081083 VL - 36 IS - 3 AU - GIDEON KOREN AU - MIHO INOUE Y1 - 2009/03/01 UR - http://www.jrheum.org/content/36/3/465.abstract N2 - Every year scores of new drugs are introduced with the hope of improving patient care. While all of them are pretested in pregnant animals, no pregnant woman takes them knowingly during premarketing studies, although sometimes pregnancies do occur. Because half of all pregnancies are unplanned, over the life cycle of the drug cases are accumulated of first trimester exposure to new agents1. How do we decide whether a drug causes congenital malformations in humans?Typically, the first line of evidence comes from case reports or case series. Case reports can be very useful, or useless, depending on simple epidemiological reality: If a specific, rare malformation occurs in association with a drug that is taken rarely in pregnancy, then a few case reports may prove causation. For example, the first few cases of anotia (lack of ears) and brain defects after isotretinoin have established causation, because the number of cases by far exceeded the rate of these rare malformations2. If the malformation in question is common (e.g., ventricular septal defect), then case reports are useless, as they may merely reflect a chance concurrence. This point will become relevant later, in the context of discussion of tumor necrosis factor (TNF) inhibitors.The second line of evidence typically comes from cohorts of exposed pregnancies that are compared to a comparison, unexposed … Address reprint requests to Dr. G. Koren, Division of Clinical Pharmacology/Toxicology, Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8. E-mail: gkoren{at}sickkids.ca ER -