The aim of this study was to observe the clinical efficacy and safety of rituximab (RTX) combination with telitacicept (TA) in patients of systemic lupus erythematosus secondary antiphospholipid syndrome (APS).

In this multicenter, prospective, observational study, 80 patients with SLE Secondary APS patients were enrolled. RTX alone or its continuation with TA was observed for 24weeks，and extended for another 24 weeks. At week 12, the RTX group could be converted to the combination group. The primary end point was the response rate of total antiphospholipid antibody (aPL) at week 12. The secondary end points included the decline rate and value of aPL antibody, aGAPSS score, remission degree of specific clinical indicators, changes in SLE disease activity in SAPS group, and drug safety at week 12 and week 24.

Inclusion Criteria:

• 1.Patients who meet 2006 Sapporo classification criteria of APS or 2020 nonstandard APS performance；

  2.Patients who meet 1997 or 2019 SLE classification criteria ;

  3.Positive LA /ACL/ aβ2GPI ,on two or more occasions, at least 12 weeks apart;

  4.with at least one extra-criteria manifestations of APS, including thrombocytopenia, hemolytic anemia, nephropathy, valve heart disease ,skin ulcer and arterial or deep vein thrombosis;

  5.Maintain a stable base treatment regimen for at least 4 weeks before screening; Basic treatment includes anticoagulants/antiplatelet agents, glucocorticoids, and hydroxychloroquine;

  6.No response, intolerance or dependence on glucocorticoids and immunosuppressants;

  7.Patients who had previously used beliumab or Telitacicept could be enrolled in the study after 12 weeks of discontinuation;

  8.Age ≥18 years;

  9.Signed Informed consent.

Exclusion Criteria:

• 1.Patients with other causes of thrombocytopenia, hemolytic anemia, valvular heart disease, kidney disease and skin ulcer symptoms were excluded, such as drugs, infections, blood system diseases, genetic metabolic diseases, etc;

  2.Severe cardiovascular diseases, kidney, liver and other important organ injuries, serious blood and endocrine system lesions (aplastic anemia, hyperthyroidism crisis, etc.) were excluded; A history of active malignancy (within 5 years) was excluded and chemoradiotherapy was performed; Patients with organ or bone marrow transplantation in the past year were excluded. Exclusion of mentally ill persons;

  3.A history of allergy to the relevant test drug;

  4.Patients had recently received a live vaccine or planned to use any live vaccine during the study;

  5.Ongoing pregnancy;

  6.Patients who were participants in clinical trials of other immunosuppressive agents/biologics within 24 weeks;

  7.Other conditions that the investigator considers would make the candidate unsuitable for the study;

1. Meet the diagnostic criteria of SLE and related symptoms of secondary APS;

2. Positive LA /ACL/ aβ2GPI ,on two or more occasions, at least 12 weeks apart;

3. One or more of the following related clinical symptoms:

1. Refractory/recurrent thrombocytopenia;
2. Autoimmune hemolytic anemia;
3. Heart valve disease;
4. Renal involvement;
5. Skin ulcer;
6. arterial or deep vein thrombosis;