325. Long-Term Rituximab Maintenance Therapy in Granulomatosis with Polyangiitis – A Single-Centre Experience
Creators: name: Thorsteinsson1, Bjarni
Publisher: name: Zenodo
Year: 2022
Subjects: Vasculitis
ANCA
Abstracts
Giant Cell Arthritis
MPA
GPA
EGPA
Takayasu
IgA vasculitis

description: <strong>Objective:</strong>Recent guidelines recommend rituximab for maintenance therapy in severe ANCA-associated vasculitis.(1) Clinical trials have described low rates of relapse with rituximab maintenance therapy.(2,3) Side effects of longstanding rituximab treatment, such as neutropenia and hypogammaglobulinemia, have been a concern and previously not investigated long-term. Here we evaluate the efficacy and tolerance of rituximab maintenance therapy in patients with granulomatosis with polyangiitis (GPA) followed at a single centre. <strong>Methods:</strong> All patients with GPA treated with rituximab as maintenance therapy, defined as lasting longer than 6 months from induction, at the Department of Rheumatology at the Uppsala University Hospital in Sweden between the years 2008-2020, were included in this retrospective analysis. <strong>Results:</strong> Thirty-two patients (19 female, 59%) were included. The median age at the start of rituximab treatment was 56 years (range 21-81). All patients had a diagnosis of GPA classified according to the EMEA (European Medicines Agency) algorithm, with 31 (97%) being positive for PR3-ANCA. Twenty-six (81%) had pulmonary involvement and 9 (28%) had renal involvement. Information was gathered on a total of 162 patient-years of rituximab therapy; median treatment duration was 4,6 years (range 0,6-13,4) and median total rituximab dose was 11 gra (range 4-23) at the time of data collection. Of the 32 patients, 21 (66%) received rituximab for control of relapse while 11 (34%) were treated for the initial disease presentation. Twenty-four patients (75%) had previously received cyclophosphamide induction therapy. All patients received induction doses of rituximab (1000 mg at 0 and 2 weeks) before being maintained on 1000 or 500 mg on a fixed schedule every 6 months. One single patient flared during maintenance rituximab therapy. The flare occurred two years after induction and the maintenance dose had just been lowered to 500 mg every 6 months. Of the 15 patients (47%) who had discontinued their rituximab treatment, 2 (13%) flared (both 2 years after their last rituximab dose; they received 4 and 6,5 years of rituximab therapy, respectively), 11 (73%) had not flared (median follow-up time 3 years; they received a median of 3,5 years of rituximab therapy) and 3 (9%) were lost to follow-up. During rituximab maintenance therapy, 18 patients (56%) had at least one infection requiring antibiotics and 3 patients (9%) were hospitalised with an infection (2 for COVID-19 and 1 for pneumonia). Two patients (6%) died during rituximab maintenance therapy, one from COVID-19 and the other of unknown causes. Hypogammaglobulinemia (IgG &lt; 6 g/L) was found in 9 patients (28%) during maintenance treatment; no patients had IgG levels &lt; 3 g/L. Transient mild neutropenia was found in two patients (6%). <strong>Conclusions: </strong>Rituximab maintenance therapy for GPA appears to be effective and safe, even long-term. Severe infections were rare and hypogammaglobulinemia was usually mild. Further studies are needed to establish the optimal dosage and duration of rituximab maintenance therapy. <strong>Disclosures:</strong> None. <em><sup>1</sup>Rheumatology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden</em>