Background Adalimumab 40mg/14days (ADA14) has demonstrated efficacy in patients with rheumatoid arthritis (RA), psoriatic arthropathy (PA) and ankylosing spondylitis (AS). In certain patients in sustained clinical remission with ADA14, a dose reduction to Adalimumab 40mg/21days (ADA21) or even Adalimumab 40mg/28days (ADA28) could be done. This strategy of extended dose could have advantages in terms of safety and costs.
Objectives The aim of the study is determine the clinical and economic impact of the use of Adalimumab dose reduction in RA, PA and AS patients in sustained clinical remission.
Methods Observational, retrospective cohort of patients in an off-label program receiving ADA21 or ADA28 for at least 6 months between Jan 2012 and Jan 2014. Inclusion Criteria: patients treated with ADA14 that achieve and maintain clinical remission (DAS28<2.6 or BASDAI<2) during 1 year and slow worsening of structural changes were selected to reduce their standard dose of ADA14 to ADA21 or ADA28. We collected age, sex, indication, duration (in years) of ADA14 during the study period. In these patients, we simulated the cost of treatment with Adalimumab as if they had received ADA14 during their ADA21 or ADA28 respective periods. Economic impact was assessed using Humira® Spanish official prices.
Results From Jan 2012 and Jan 2014, 109 patients received adalimumab (46 RA, 37 PA and 26 AS). 18 patients (16%) (9 women; 7 RA, 6 PA, 5 AS) received adalimumab in extended dose regimen: 15 ADA21 and 3 ADA28 for at least 0.5 years (1.2±0.4 years; range 0.6-1.9 years). At 1st Jun 2014, 16 (89%) patients (6 RA, 6 PA and 4 AS) continued on adalimumab reduced dose (12 ADA21 and 3 ADA28) in clinical remission. 2 (11%) patients discontinued due to: 1 patient due to reactivation of RA (switched to ADA 14 and achieved clinical remission) and 1 patient due to reactivation of AS (switched to ADA 14 and achieved clinical remission). Total associated costs of this low dose strategy throughout the observation period were €159.144. If these patients had been treated with ADA 14, the total cost of therapy would have been €251.085. The implementation of the adalimumab extended dose in these patients saved €91.941 during 2 years. This cost savings achieved with an adalimumab extended dose regimen could lead to treat approximately 7 additional patients with RA, PA or AS for a year without increasing the total cost of adalimumab therapy.
Conclusions Adalimumab extended dose regimen produces important cost savings when used in patients who maintain clinical remission for at least 1 year with ADA 14. Spacing the dosage in selected patients could make treatment more cost-effective and allow physicians to treat more patients with a fixed budget
Disclosure of Interest : None declared