OBJECTIVES: Methotrexate is the main first-line systemic therapy in rheumatoid arthritis (RA) and psoriasis (PSO, after topical treatments), with a progressive dose/route optimization before considering biotherapy. This study aimed to describe the number of patients with RA or PSO initiating methotrexate, its optimization before biotherapy, and biotherapy economic impact.

METHODS: This was an observational cohort study using claims data from the French national insurance database. Adults initiating methotrexate for RA (2016-2017) or PSO (2017-2018) were followed from methotrexate initiation to end of study or death. RA identification used diagnosis codes (ICD-10 M05, M06), excluding patients with lupus, scleroderma or myositis. PSO identification used ICD-10 L40 (except L405) and topical vitamin-D dispensations, excluding patients with ≥2 intra-articular steroid injections or ≥4 NSAIDs dispensations. Persistence and time to biotherapy were assessed using Kaplan-Meier estimator. Costs were assessed 6 months before and after biotherapy initiation.

RESULTS: Overall, 15,668 (RA) and 4,820 (PSO) patients initiated methotrexate during selection period, respectively, mainly orally (≈80%). Mean age was 60.8 years (RA), and 52.6 years (PSO). After five years, 55.8% (RA) and 32.1% (PSO) of patients were still treated with methotrexate, while 26.2% (RA) and 40.3% (PSO) escalated to biotherapy, respectively. Overall, 3,582 patients (RA) and 1,693 patients (PSO) escalated to biotherapy. Among RA patients, 2,604 (72.7%) initiated with oral methotrexate, of whom 1,121 (43.0%) directly escalated to biotherapy. For PSO, 1,693 (77,3%) initiated with oral methotrexate, of whom 979 (74.8%) escalated directly. Mean costs 6 months before and after biotherapy initiation were €4,091 and €7,672 for RA, and €1,974 and €6,627 for PSO, respectively.

CONCLUSIONS: Despite a good persistence, >40% of RA patients and >70% of PSO patients escalated to biotherapy without methotrexate optimization. Treatments accounted for ≤10% of costs before biotherapy, and >50% afterwards. Methotrexate optimization would help delaying biotherapy escalation and its costs.