Safety of tacrolimus in autoimmune disease: Results from post-marketing surveillance in South Korea

Objective. Tacrolimus, a macrolide immunosuppressant, is approved in Korea for the treatment of rheumatoid arthritis (RA), lupus nephritis (LN) and myasthenia gravis (MG). We report three prospective post-marketing surveillance studies of tacrolimus conducted in South Korea in these indications. Methods. Studies were conducted according to South Korean Ministry of Food and Drug Safety requirements. Patients were followed up for the duration of the study (up to 4 years) or until treatment discontinuation. Occurrence and likely relationship with tacrolimus of adverse events (AEs), adverse drug reactions (ADRs; defined as AEs where causal relationship to tacrolimus could not be excluded) and serious AEs were recorded. Association of AEs with demographic and medical factors was evaluated by multivariable analysis. Results. The studies included 740 (RA), 307 (LN) and 104 (MG) patients. The incidence of AEs was 12.7% in RA (64.2% of AEs potentially related to tacrolimus), 20.9% (37.8% potentially related) in LN and 29.8% (56.8% potentially related) in MG. The incidence of ADRs was 8.4%, 9.8% and 20.2%, respectively. Serious AEs were reported in 0.7%, 7.2% and 8.7%, respectively. The most common AEs were abdominal pain (RA), pharyngitis (LN) and diarrhea (MG). Unexpected AEs occurred in 3.5% of patients with RA, 2.9% in LN and 8.7% in MG; no pattern of unexpected AEs was apparent. Multivariable analysis demonstrated that patients with comorbidity had higher probability of experiencing an AE in RA and MG studies. Conclusion. The incidence of AEs and the safety profile of tacrolimus in each indication was consistent with previous reports.