Long-Term Etanercept Well Tolerated, Shows Durable Response in Patients With JIA

The overall safety and efficacy of etanercept were favorable in the treatment of juvenile idiopathic arthritis.

Treatment of juvenile idiopathic arthritis (JIA) with etanercept over a 10-year period was found to be well tolerated and had a favorable safety profile, according to study results published in Rheumatology.  

Researchers conducted an open-label extension of a phase 3b single-arm trial (CLIPPER; ClinicalTrials.gov Identifier: NCT00962741) and reported on the long-term safety and efficacy of etanercept among patients with JIA.

In the current study (CLIPPER2; ClinicalTrials.gov Identifier: NCT01421069), all participants from CLIPPER (ie, children diagnosed with JIA, categorized as extended oligoarticular arthritis [eoJIA], enthesitis-related arthritis [ERA], or psoriatic arthritis [PsA], who received treatment with once-weekly 0.8 mg/kg etanercept) were eligible.

The primary endpoint was the occurrence of malignancy. Secondary endpoints included safety and efficacy profiles, number of serious adverse events (SAEs), infections, and long-term health outcomes.

Efficacy was assessed using the JIA American College of Rheumatology (ACR) core measures.

A total of 109 (86%) patients from CLIPPER were enrolled in CLIPPER2. Overall, 84 patients (66%) completed the 10-year study, with 32 (25%) receiving active treatment at the time. A total of 55 cases of JIA were categorized as eoJIA, 31 as ERA, and 23 as PsA. More than half of study participants were girls; mean age at the start of CLIPPER was 11.7 years.

Overall, etanercept was well tolerated, and the benefit-risk assessment remains favourable in this population.

A single case of malignancy (Hodgkin disease) was reported during both the studies. The patient was withdrawn from the study. 

Overall, the number and incidence of treatment-emergent AEs (TEAEs) decreased throughout the study, with rates of serious TEAEs remaining low. Headache (28 TEAEs in 17 patients) and arthralgia (24 TEAEs in 16 patients) were the most common TEAEs. A total of 40 SAEs were reported by 30 patients, at a rate of 3 or fewer events each.

The number of treatment-emergent infections also decreased over the study period, with rates of serious infections remaining low. Infection rates did not increase with long-term exposure to etanercept. A total of 672 infections were reported by 108 patients, the most common being upper respiratory tract (168 infections) and pharyngitis (104 infections).

The JIA ACR response rates remained stable over the 10-year study period. From month 2, 127 patients achieved JIA ACR50 responses. In addition, 42 patients achieved remission according to the Juvenile Arthritis Disease Activity Scores and 34 achieved remission according to ACR clinical remission criteria.

The study was limited by the lack of a control group and its nonrandomized open-label design. In addition, many patients withdrew from the study and treatment.

Researchers concluded, “The safety profile of etanercept during the 10 years of total follow-up was similar to that in previous JIA studies and consistent with the known safety profile of etanercept. Efficacy results were consistent with the profile of etanercept. Overall, etanercept was well tolerated, and the benefit-risk assessment remains [favorable] in this population.”

Disclosure: This research was supported by Pfizer. Multiple study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Vojinović J, Foeldvari I, Dehoorne J, et al; on behalf of the Rheumatology International Trials Organisation (PRINTO). Ten-year safety and clinical benefit from open-label etanercept treatment in children and young adults with juvenile idiopathic arthritis. Rheumatology (Oxford). Published online May 4, 2023. doi:10.1093/rheumatology/kead183