Immune thrombocytopenia (ITP) is a haematological manifestation secondary to connective tissue disease (CTD). Many patients with CTD-ITP are refractory to glucocorticoids (GCs) plus immunosuppressant agents (ISAs); rituximab (RTX) is the recommended second-line therapy. Belimumab (BLM) shows efficacy against CTD. We compared the efficacy and safety of RTX and BLM.

Data of patients with CTD-ITP refractory to GCs plus ISAs administered were collected. The data of 11 patients with refractory CTD-ITP who received BLM were compared with those of 15 patients treated with RTX.

At week 2, BLM resulted in a better overall response (OR) than RTX (72.7% vs 26.7%, p=0.045). The OR rate was 60.0% (9/15), 66.7% (10/15) and 73.3% (11/15) at week 4, 8 and 12, respectively, in the RTX group. It remained at 72.7% (8/11) during week 4-12 in the BLM group. Excluding the data of three deceased patients, the OR rate dropped at week 24 in both groups (RTX vs BLM, 61.5% (8/13) vs 70.0% (7/10), p=1.000). At week 24, four patients with OR in both groups successfully withdrew GCs to <15 mg prednisone (RTX vs BLM, 40% (4/10) vs 66.7% (4/6), p=0.608). The serum C3 level did not significantly change, whereas the serum immunoglobulin G level significantly decreased at week 4, 8 and 12 in both groups. There were three patients with serious adverse effects who died of severe pneumonia during weeks 12-24.

BLM may be a safe and effective alternative to RTX for CTD-ITP refractory to GCs plus ISAs.