SINGLE CENTER EXPERIENCE OF RITUXIMAB TREATMENT FOR IGG4-RD DISEASE IN A LARGE MULTI-ETHNIC COHORT
Authors: Matthew Colquhoun et al.
IgG4-related disease (IgG4-RD) is characterized by a fibrosing-inflammatory histology and abundant IgG4 positive plasma cells. It can affect almost any organ system. Several DMARDs have been proposed to treat IgG4-RD. In this retrospective study, the efficacy of RTX was analyzed.
45 patients received treatment with RTX. The median age was 62, and 66% were male. Multiple ethnic backgrounds were represented; 20% black, 20% white and 60% Asian. The average number of organs affected was 2.9 (range 1-7) and the average IgG4-RD Responder Index (RI = manifestations of disease activity present in the last 28 days) prior to treatment was 10.02. 8/44 (18%) were on another conventional immunosuppressant at the time of RTX induction and 27/44 (61%) had concurrent treatment with glucocorticoids. All patients demonstrated reduced disease activity post RTX with an average IgG4-RI of 2.4. 2/34 (6%) remained stable; 21/34 (62%) showed a partial response; 11/34 (33%) had a complete response. Intercurrent flares did occur in 9 patients, 7 of whom had concurrent B cell repopulation. 15 patients completed two years of consistent RTX-induced B cell depletion with no subsequent flares (average follow up 15 months). 12/45 (27%) experienced an adverse event including infection requiring admission (4), hypogammaglobinaemia (2), infusion reaction (1) and death (5; 11%; average age 81).
The data confirm that RTX is an effective agent to remit IgG4-RD. They also illustrate the broad variety in disease evolution from chronic relapsing disease to stable complete remission. Unfortunately, still little is known about prognostic factors. Whether B cell monitoring has an effect on outcome will have to be shown in a prospective study.