What Predicts Initial Biologic Disease-Modifying Antirheumatic Drug Failure in Psoriatic Arthritis and How Common Is It?

Secondary failure of a biologic disease-modifying antirheumatic drug (bDMARD) describes loss of therapeutic response over time after initial response, in contrast to the less commonly observed primary failure, where there has been an inability to achieve an initial response given an adequate period of treatment. Whereas it is well studied in patients with rheumatoid arthritis (RA), this issue has been less well examined in prospective psoriatic arthritis (PsA) patient cohorts.