TREATMENT OF GIANT CELL ARTERITIS WITH TOCILIZUMAB IN CLINICAL PRACTICE IN SWEDEN

• Giant cell arteritis (GCA) is the most common form of systemic vasculitis in adults. GCA is often associated with comorbidities related to the disease itself or caused by its treatment, here: mainly glucocorticosteroids. Since 2017, tocilizumab (TCZ) is approved for the treatment of GCA, but its uptake and treatment outcomes in clinical practice remain to be characterized.Objectives:To describe characteristics of GCA patients treated with tocilizumab (TCZ) in clinical practice, to evaluate the use of prednisolone up until and following TCZ treatment start, and to describe the TCZ treatment duration.Methods:We linked together the Swedish Rheumatology Quality Register (SRQ), the national Prescribed Drug register, and national Patient register, covering data from July 2009 until July 2019. Through these linkages, we identified GCA patients treated with TCZ including start and discontinuation, their comorbidities and use of other medications. TCZ treatment durations were evaluated through survival probability curves.Results:We identified 468 patients with GCA treated with TCZ, before and after its formal approval for GCA, Table 1. Over calendar time, the proportion who started TCZ as first ever bDMARD increased, as did the mean age at start of TCZ. The pattern of co-morbidities and health care utilisation demonstrated substantial burden from, e.g., diabetes and infections (Table). Patients starting treatment with TCZ were characterized by an increasing average dose of prednisolone during the last 1.5 years before TCZ start. Thereafter, prednisolone use declined substantially, from a mean of 15 mg/day in the six months before the start of TCZ to 6 mg/day 1 year after its start (Figure 1). Analysis of the duration of TCZ treatment (from start until discontinuation) suggested that at one year, two thirds of patients were still on treatment (Figure 2).Table.Swedish GCA patients starting treatment with tocilizumab July 2009 - Nov 2019.July 2009 -July 2015July 2016 - July 2017July 2017 -July 2018July 2018 - Nov 2019Patients8914014099Female64%77%73%71%Age, mean (sd)67 (7.9)68 (8.8)69 (8)70 (7.8)Previous use of bDMARDs27%21%11%11%Hospitalisations most recent 5 years, mean (sd)3.9 (4.2)3.2 (2.6)2.9 (2.5)3.3 (3)Co-morbidities, most recent 5 years:Chronic obstructive pulmonary disease6%2%4%3%Ischemic heart disease12%7%14%11%Diabetes mellitus, type 1&234%26%26%26%Fractures (any location)15%14%11%10%Knee/hip replacement7%10%7%8%Myocardial infarction2%1%4%3%Stroke2%4%2%5%Hospitalisation listing infection39%40%39%37%Figure 1.Average daily dose of prednisolone before and after* start of tocilizumab, based on cumulative dose every 6 months. *The average daily dose of prednisolone after the start of TCZ is calculated only among patients who were still on treatment at the end of each period (351 patients in the first 6 months, 251 in 6m-1y, 161 in 1 – 1.5 y, 95 in 1.5 – 2y).Figure 2.Kaplan-Meier curve for tocilizumab in GCA by time since treatment start.Conclusion:Patients treated with TCZ for GCA in clinical practice are characterized by a significant burden of co-morbidities, many of which may be related to prolonged use of glucocorticosteroids. This study confirms a marked reduction in the use of oral prednisolone following treatment with TCZ, and demonstrates that in a majority of patients in clinical practice, treatment with TCZ for GCA is extended beyond one year. Future analyses will evaluate the association of these observed treatment patterns with the level of GCA disease control, co-morbidities and quality of life, over time.Acknowledgments:These analyses was partly funded through an agreement between Roche and Karolinska Institutet.Disclosure of Interests:Daniela Di Giuseppe: None declared, Ann Knight: None declared, Aladdin J Mohammad Speakers bureau: lecture fees from Roche and Elli Lilly Sweden, PI (GiACTA study), Carl Turesson Grant/research support from: Unrestricted grant from Bristol-Myers Squibb, Consultant of: Roche, Speakers bureau: Abbvie, Bristol Myers-Squibb, Pfizer, Roche, Johan Askling Grant/research support from: JA acts or has acted as PI for agreements between Karolinska Institutet and the following entities, mainly in the context of the ARTIS national safety monitoring programme of immunomodulators in rheumatology: Abbvie, BMS, Eli Lilly, Merck, MSD, Pfizer, Roche, Samsung Bioepis, Sanofi, and UCB Pharma

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