Tofacitinib: the first Janus kinase (JAK) inhibitor for the treatment of rheumatoid arthritis

Objective: To review the pharmacology, pharmacokinetics, efficacy and safety, dosage administration, and adverse effects of tofacitinib for rheumatoid arthritis (RA) treatment. Data Sources: Primary sources of information were obtained from clinical studies, which were identified through PubMed (1966 to June 2013) and International Pharmaceutical Abstracts (1970 to March 2013) using terms: tofacitinib, tasocitinib, CP-690550, and CP-690,550. Information was used from tofacitinib package insert, guidelines, and published abstracts from the American College of Rheumatology (ACR) and the European League Against Rheumatism. Study Selection and Data Extraction: Data search was limited to include publications in English language and from human subjects. Data Synthesis: Tofacitinib is the first oral Janus kinase inhibitor indicated for treatment of moderate to severe RA. Tofacitinib demonstrated efficacy and safety comparable to other disease-modifying antirheumatic drugs (DMARDs). Tofacitinib was efficacious in RA patients, indicated by achievements of ACR20, ACR50, and ACR70 criteria. Similar improvements were observed in patients who met remission criteria based on the Disease Activity Scores 28 criteria and quality of life as measured by the Health Assessment Questionnaire-Disability Index (HAQ-DI). Tofacitinib was associated with infections and malignancies; and elevations in serum creatinine and lipids were observed. Drug interactions with inducers and inhibitors of the cytochrome P-450 3A4 and 2C9 isoenzymes were reported. Conclusions: Tofacitinib is an oral treatment option for RA patients who have inadequate response or intolerance to methotrexate. Postmarket surveillance will provide further insight to tofacitinib’s role in RA therapy, especially in patients who may require different types of combination therapy with DMARDS