P108 Filgotinib for Rheumatoid Arthritis: an observational cohort to assess clinical effectiveness in a single centre
Authors: Box Christopher D , Ramsay Susan , McKay Neil D 
Published: April 2024

Background/Aims

Filgotinib, a Janus-kinase (JAK) 1 preferential inhibitor, was approved for use in the UK in moderate or severe rheumatoid arthritis (RA) in 2021, as monotherapy or in combination with Methotrexate. Evidence of real-world effectiveness is currently limited.

Methods

Patients prescribed Filgotinib between December 2021 and August 2022 in NHS Lothian were identified from pharmacy registration data. All underwent clinical efficacy assessment at three months. Electronic patient records (EPR) were reviewed to record baseline data including previous and current treatments. Duration of Filgotinib treatment was recorded, and discontinuation reason if applicable. DAS-28 scores within six months prior to starting Filgotinib were recorded, along with available subsequent scores. Pre-existing interstitial lung disease (ILD), venous thromboembolism (VTE), major adverse cardiovascular events (MACE) and malignancy were recorded, along with incident events during treatment.

Results

145 patients were prescribed Filgotinib; 106 (73.1%) females and 39 (26.9%) males, with median age 64 years. Median treatment duration was 447 days. 35 (24.1%) were treated with the reduced 100mg dose. 81 (55.9%) received conventional disease-modifying anti-rheumatic drugs (DMARDs) alongside Filgotinib. 41 (28.3%) patients discontinued treatment: 10 (6.9%) due to loss of effect; 16 (11.0%) due to lack of efficacy; six (4.1%) experienced side effects leading to cessation; five (3.4%) stopped for alternative reasons; one (0.7%) experienced a severe allergic drug reaction; three (2.1%) developed lung cancer and treatment was stopped in each case. 12 (8.3%) patients had ILD prior to treatment. 10 (6.9%) had prior major cardiovascular events, eight (5.5%) had previously treated malignancy, and six (4.1%) had previous VTE. During treatment, 1 (0.7%) patient developed ILD and two (1.4%) developed VTE. There were three (2.1%) new malignancies, all lung cancer. No new MACE occurred. 120 (82.8%) patients were previously treated with biologic or targeted synthetic DMARDs. 59 (40.7%) had failed multiple biologic DMARDs of different classes. 19 (13.1%) switched to Filgotinib from another JAK inhibitor. Pre-treatment DAS-28 scores were recorded in 55 (37.9%) patients with mean 5.1, and during treatment in 44 patients (30.3%) with mean 3.5. 17 (11.7%) patients had DAS-28 recorded both before and during treatment, with pre-treatment mean 5.0 and subsequent mean 2.9. Of these, 10 (58.8%) were classified as a good response by EULAR disease activity criteria, and four (23.5%) as a moderate response. Three (17.6%) were non-responders.

Conclusion

Our cohort includes 40.7% difficult-to-treat RA. Drug survival as a clinical efficacy surrogate was 71.7% at median duration 447 days, demonstrating patient acceptability and clinical effectiveness. Our service is poor at DAS-28 recording in the EPR, which may partly reflect imaging use at response assessment. Since this cohort was established, the European Medicines Agency has issued guidance advising caution using JAK inhibitors in high-risk groups to minimise the chance of serious side effects.

Disclosure

C.D. Box: None. S. Ramsay: None. N.D. McKay: Other; N.D.M. has received funding for conference registrations from Abbvie, UCB and Novartis, fees for lecturing from Gilead, and has taken part in advisory board meetings for UCB and Gilead.