Background/Purpose: Very few studies have compare different agents used in the treatment of rheumatoid arthritis (RA) over the very long term. The majority of them have a short duration, are open-label, have selection criteria, and compare outcome measures such as DAS score, DAS improvement, HAQ improvement and so on. Rhumadata, a real-life database and registry, enrols all patients for whom a specific diagnosis such as RA has been made thus enabling comparisons of retention rates in a large population and the analysis of potential predictors of retention. Our objectives are to compare the retention rate of adalimumab and etanercept after DMARDs failure in a population of RA patients and identify potential predictors of retention rate.

 Methods: Data of RA patients prescribed either etanercept (ETA) or adalimumab (ADA) as first biologic agent on or after January 1st, 2002 was extracted.  The data included age and gender, disease characteristics, clinical variables, patient and physician specific assessments, laboratory measures and composite assessment of disease activity (DAS28-ESR, SDAI and CDAI). All patients were followed until they discontinued their treatment or June 2, 2015, the date at which the data was extracted from Rhumadata®. Secondary diagnoses and comorbidities established at or before the administration of the biologic agents were coded using the ICD-9-CM codes. Infections occurring during treatment, biologic status (ongoing or stopped) and the reasons for biologic cessation were also extracted. The 10-year drug retention rates were estimated and compared using Kaplan-Meier survival estimates and potential predictors were identified using univariate proportional hazard regression models. Statistical analysis was performed using SAS version 9.4.

 Results: The data from 548 RA patients (184 prescribed ADA and 364 etanercept) as first biologic agent were extracted from the RHUMADATA® clinical registry and database. The patients were mostly women (74.5%) and had an average age of 53.3(SD=12.8).  The patients had an average disease duration of 7.1 years (SD=8.0) and provided 2327.3 person-years of observation. The 10-year retention rates of ADA and ETA were estimated at 27.2% (SD=3.9%) and 35.0% (SD=3.1%) respectively and an overall significant difference in retention rate was observed (log-rank p -value = 0.0031). Inefficacy of biologic was the principal reason for drug cessation (46% in both ADA and ETA) followed by adverse events (14.8% ADA and 11.7% ETA). Univariate proportional hazard models identified the biologic used (HR (ADA vs ETA) = 1.402, 95% CI: 1.120 to 1.755) and fatigue-VAS (HR (per unit increase in fatigue-VAS) = 1.402, 95% CI: 1.120 to 1.755) as significant predictors of retention (alpha=0.05). Concurrent use of nbDMARDs did not however reach statistical significance (HR (combination vs monotherapy) = 1.157, 95% CI:  0.842 to 1.591).

 Conclusion: After 10 years of continuous exposure to a first biologic agent, etanercept offers a clinically small but statistically significant advantage over adalimumab in a population of RA patients.

Inefficacy of biologic was the principal reason for drug cessation (46% in both ADA and ETA) followed by adverse events (14.8% ADA and 11.7% ETA). 

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/etanercept-has-a-better-retention-rate-at-10-years-than-adalimumab-in-patients-with-rheumatoid-arthritis-results-from-rhumadata-a-real-life-clinical-database-and-registry/