Development of active tuberculosis in patients treated with biological disease-modifying antirheumatic drugs

Background. Biological disease-modifying antirheumatic drugs (bDMARDs) have been shown to be highly effective in the treatment of rheumatic conditions, but may increase the risk of infections. Development of tuberculosis (TB) while on bDMARD therapy is of particular concern in high TB burden settings such as Western Cape Province, South Africa. Objectives. To describe the diagnosis, management and outcome of patients who developed active TB while receiving a bDMARD. Results. Ten patients who screened negative for TB prior to initiation of a bDMARD subsequently developed active TB. TB was diagnosed between 10 months and 9 years from bDMARD initiation, suggesting new infection, and included 6 cases of extrapulmonary TB. All patients required multiple tests to confirm the diagnosis of TB, and all were successfully treated. Conclusions. TB can occur in patients on bDMARD therapy despite initial screening, and may have unusual, extrapulmonary manifestations that pose a diagnostic challenge.