We aimed to assess the long-term effects and safety of rituximab for the treatment of pemphigus in the Chinese population. In this retrospective study, 74 pemphigus patients treated with rituximab from February 2008 to December 2018 and followed up were included and analyzed. Lymphoma protocol (LP, 375mg/m2 per week for 4 weeks) or rheumatoid arthritis protocol (RAP, 1000mg on the 1st and 15th day) was used as rituximab protocol. The median follow-up duration was 26.1 months. Complete remission (CR) rate was 66.2% and the median time to achieve CR was 11.0 months. Six patients received rituximab as first-line treatment and all achieved CR, while the CR rate of other patients was 63.2% (Table 1). Thirteen (26.5%) in 49 CR patients relapsed. The median relapse time was 12.3 months (Figure 1). No significant effect of rituximab protocol on CR rate (P = 0.172) and relapse rate (P = 0.907) was observed, but RAP protocol had a shorter time to achieve CR (11.8 months vs 6.8 months, P = 0.016, Table 1). In baseline and during follow-up, levels of anti-desmoglein autoantibodies, CD19+B cells, CD4+T cells, CD8+T cells and immunoglobulins were collected and adverse events were recorded. Autoantibody level was found to change with the disease conditions. Eighteen severe adverse events (SAE) occurred in 13 (17.6%) patients (Table 2). The most common SAE was pulmonary infection (13.5%, 10/74) with the median time of 64.5 days from rituximab treatment to events. In those patients, 9 (90.0%) patients were with lower IgM level than normal limit. Three patients (4.1%) died because of severe pulmonary infections within 3 months. They were all evaluated as immunosuppressed at baseline. This first long-term research suggests that rituximab is an effective treatment for pemphigus with a high CR rate in the Chinese population. Patients taking rituximab as first-line treatment rather than non-first line treatment may be more likely to achieve CR. Pulmonary infection during treatment could be fatal and worthy of attention.

Long-term effectiveness and safety of rituximab for the treatment of pemphigus in Chinese population