Background Tofacitinib is a novel, oral Janus kinase inhibitor for the treatment of rheumatoid arthritis. Phase (P) 3 studies demonstrated tofacitinib is effective and has a manageable safety profile at both 5 and 10 mg twice-daily (BID) doses.
Objectives To assess, using post-hoc analyses of P3 data, whether active treatment could affect monthly medical expenditure (MME) compared with placebo.
Methods Data from patients with an inadequate response (IR) to methotrexate (MTX) or TNF inhibitors (TNFi) receiving tofacitinib 5 or 10 mg BID, or adalimumab (ORAL Standard only), in combination with methotrexate, were assessed from two randomised P3 studies (ORAL Standard, NCT00853385 [MTX-IR] and ORAL Step, NCT00960440 [TNFi-IR]). Differences across treatment groups in estimated MME were evaluated using a longitudinal model. A total of three models were run for each study, each with one of the following variance–covariance structures: 1) unstructured, 2) auto-regressive of order 1 and 3) compound symmetry. The final variance–covariance structure was selected based on Akaike's Information Criteria.
Results Estimated MME by treatment group for MTX-IR in ORAL Standard is presented in Fig. 1a. By Month 1 mean MME was significantly lower in the active treatment groups when compared with placebo; the MME was decreased −$89 for the tofacitinib 10 mg BID group compared with an increase of $70 in both the tofacitinib 5 mg BID and adalimumab groups. During the placebo-controlled phase of ORAL Step, estimated MME by treatment group for TNFi-IR decreased from baseline to Month 1. Between Month 1 and Month 3 the MME of the placebo group increased but declined further in the two active tofacitinib treatment groups (Fig. 1b). By Month 3 the reduction in MME was over $100 greater in each of the two tofacitinib groups when compared with placebo.
Conclusions Tofacitinib is expected to have a positive impact on medical expenditure over time compared with placebo.
Acknowledgements Editorial assistance was provided by Mark Walker PhD, of Complete Medical Communications and funded by Pfizer Inc.
Disclosure of Interest R. Rendas-Baum: None declared, M. Kosinski: None declared, A. Singh Shareholder of: Pfizer Inc., Employee of: Pfizer Inc., C. Mebus Shareholder of: Pfizer Inc., Employee of: Pfizer Inc., B. Wilkinson Shareholder of: Pfizer Inc., Employee of: fizer Inc., R. Riese Shareholder of: Pfizer Inc., Employee of: Pfizer Inc., G. Wallenstein Shareholder of: Pfizer Inc., Employee of: Pfizer Inc.