Evaluating personalised treatment by using serum drug levels of adalimumab in rheumatoid arthritis patients: a cost-effectiveness analysis

Objective To evaluate the cost-effectiveness of personalised treatment for rheumatoid arthritis (RA) using clinical response and serum adalimumab levels. Methods A personalised treatment algorithm defined, based on clinical response and drug levels at 6 months, whether adalimumab treatment should be continued, discontinued or whether dosing should be altered or a specific next biological treatment should be started. Outcomes were simulated using a patient level Markov model, based on a cohort of 272 adalimumab-treated RA patients and data of patients from the Utrecht Rheumatoid Arthritis cohort. Costs, clinical effectiveness and Quality Adjusted Life Years (QALYs) were compared with outcomes as observed in usual care and Incremental Cost-Effectiveness Ratio’s (ICERs) were calculated. All analyses were performed probabilistically. Results Clinical effectiveness was higher for the cohort simulated to receive personalised care compared to usual care; the average difference in QALYs was 3.84 (95 percentile range -8.39 to 16.20). Costs were saved on drugs: €2,314,354. Testing costs amounted to €10,872. Mean total savings were €2,561,648 (95 percentile range -3,252,529 to 1,898,087), resulting in an ICER of €666,500 or €646,266 saved per QALY gained from a societal or healthcare perspective, respectively. In 72% of simulations personalised care saved costs and resulted in more QALYs, in 28% it was cost-saving with lower QALYs. Scenario analyses showed cost-saving along with QALYs gain or limited loss. Conclusions Tailoring biological treatment to individual RA patients using drug levels and short-term outcome is cost-effective. Results underscore the potential merit of personalised biological treatment in RA.