Efficacy of telitacicept in patients with lupus- and antiphospholipid syndrome-associated refractory thrombocytopenia

IntroductionThrombocytopenia, a common noncriteria manifestation of antiphospholipid syndrome (APS), is severe in approximately one-third of patients with APS. However, there are no guidelines for treating such thrombocytopenia. B-cell-targeting therapy may be an option in refractory cases; however, its efficacy has not been firmly established. Here, we report on two patients with refractory antiphospholipid antibodies (aPLs)-associated thrombocytopenia treated with telitacicept. Case DescriptionCase 1, a 39-year-old woman, presented with systemic lupus erythematosus (SLE) and APS with diffuse alveolar hemorrhage, persistent thrombocytopenia, and recurrent miscarriages. The thrombocytopenia had been refractory to multiple lines of treatments, the most recent being mycophenolate mofetil and prednisone (5 mg/day). After receiving telitacicept (160 mg/week) for 3 months, she had presented with decreased titers of aPLs and a slight increase in platelet counts (14 x 10(9) to 35 x 10(9)/L). Case 2, a 51-year-old woman, presented with SLE and APS with refractory thrombocytopenia. She had been diagnosed with pulmonary tuberculosis 4.5 years ago and received antituberculosis therapy for 2 years. She had also undergone pulmonary lobectomy 4 years ago for lung adenocarcinoma. Her thrombocytopenia relapsed (lowest 14 x 10(9)/L) when prednisone was tapered to <10 mg/day. After adding telitacicept (160 mg/week) to cyclosporin A (150 mg/day) and hydroxychloroquine (400 mg/day) for 5 months, aPLs decreased and platelet counts increased (78 x 10(9) to 183 x 10(9)/L), enabling halving of her dose of prednisone from 15 to 7.5 mg/day. Neither patient had any adverse effects. ConclusionTelitacicept can safely reduce aPLs titers and improve refractory thrombocytopenia in patients with secondary APS. Randomized-controlled trials to assess its effectiveness are urgently required.