Background Catastrophic antiphospholipid syndrome (APS) is characterized by thrombosis in multiple organs developing over a short period of time. The combined therapy of anticoagulation plus glucocorticoids plus plasma exchange and/or intravenous immunoglobulin is the first-line treatment. Despite this regimen, the mortality remains high and new treatment options are needed. Rituximab, a chimeric monoclonal antibody against CD20, has demonstrated in observational studies that may be effective for the treatment of patients with refractory forms of systemic lupus erythematosus (SLE).
Objectives To describe the main clinical manifestations, laboratory features, and outcome of patients with catastrophic APS treated with rituximab.
Methods We reviewed the web-based international Catastrophic APS registry (“CAPS Registry”) for rituximab-treated patients. The registry contains clinical, laboratory, and therapeutic data on all reported cases of catastrophic APS, and can be freely consulted through the Internet (http://infmed.fcrb.es/es/web/caps).
Results We identified 15 patients with catastrophic APS treated with rituximab. Median age of patients was 36.4 years (range 3 months-69 years). Eleven (73%) patients were female, 9 (60%) suffered from primary APS, 4 (27%) from SLE, and the remaining two patients from splenic marginal-zone lymphoma and overlap syndrome, respectively. In 8 (53%)patients, precipitating factors were identified. The most frequent precipitating factor, found in 5 patients, was infection. Problems related to anticoagulation treatment were identified in 2 cases and trauma in the remaining case.
Lupus anticoagulant was reported as positive in 9/11 patients, the IgG isotype of anticardiolipin antibodies (aCL) in 10/12 (83%) and the IgM isotype of aCL in 4 (50%). The IgM isotype of anti-β2-glycoprotein I antibodies were positive in only 5 patients and the IgG isotype in 4 patients.
In 2 patients, the administration of rituximab as first or second-line was not specified in the registry. Four (31%) out of 13 patients received rituximab as first-line treatment associated with combined therapy of catastrophic APS: In 3 of them, the reason was the severity of clinical picture and in the remaining, rituximab was administered as a treatment of lymphoma. In 9 (69%) patients, rituximab was the second line-therapy due to poor response to initial treatment in form of recurrent episodes of catastrophic APS in 2 patients, worsening of thrombocitopenia in one patient and worsening of thrombotic clinical picture in 3 patients (in the remaining 3 patients, the reason for rituximab was not specified).
Rituximab was used in a different fashion, including 375 mg/m2 once weekly for 4 weeks (4 patients) or two infusions of 500-1000 mg one or two weeks or a month apart (3 patients). No adverse events were described in relation to the rituximab. After a mean follow-up of 14.8 ± 11.8 months, only 3 (20%) patients died.
Conclusions Rituximab may be effective for the treatment of patients with severe or refractory catastrophic APS.
Disclosure of Interest None Declared