Effectiveness and safety of eltrombopag in connective tissue disease patients with refractory immune thrombocytopenia: a retrospective study

Objectives We aimed to investigate the safety and effectiveness of eltrombopag for adult patients with refractory immune thrombocytopenia (ITP) secondary to connective tissue disease (CTD). Methods This is a single-centre, retrospective cohort and propensity score-matched study. Data from CTD-ITP patients treated with eltrombopag between January 2019 and January 2023 were retrospectively analysed. Baseline characteristics and follow-up information were recorded. CTD patients without ITP were matched to identify the risk factors associated with CTD-ITP performed by Logistic regression analysis. Results Twenty patients were enrolled, including 5 systemic lupus erythematosus (SLE), 9 Sjogren's syndrome (SS) and 6 undifferentiated connective tissue disease (UCTD). Nineteen (95%) patients were female, and the median age was 59 years. Logistic regression analysis showed that anaemia (OR = 8.832, P = 0.007) was associated with increased risk of ITP, while non-erosive arthritis (OR = 0.045, P = 0.001) and interstitial lung disease (OR = 0.075, P = 0.031) were associated with reduced risk. Fourteen patients (70%) achieved a complete response (CR) and one (5%) achieved a partial response (PR). The median response time was 14 days. The median platelet count was 8.5 x 10(9)/l at baseline of eltrombopag and increased to 122 x 10(9)/l after 4 weeks. No adverse events were observed. Conclusions Eltrombopag appears to be effective, safe and well-tolerated in refractory ITP patients with CTD; larger studies are needed to confirm the generalizability of these findings. What does this mean for patients? Connective tissue disease (CTD) is a group of autoimmune diseases involving multiple systems and organs. Thrombocytopenia occurs when the blood system is involved. Severe thrombocytopenia may cause systemic bleeding and can even be life-threatening. At present, there are many treatments for immune thrombocytopenia (ITP) caused by CTD. However, some patients do not respond to these treatments, so we need to find new treatment strategies. Eltrombopag is a type of drug called a thrombopoietin receptor agonist. It stimulates bone marrow to produce more platelets. In recent years, eltrombopag has been widely used in primary ITP, but there are few studies on CTD-ITP. We reported on a retrospective series of 20 CTD-ITP patients treated with eltrombopag after no response to first and second treatment options. We found 70% complete response (i.e. 70% of patients had no detectable disease), and the drug was well tolerated. No undesired side effects were observed. Our study provides more evidence for the use of eltrombopag to treat CTD-ITP that has not previously responded to treatment.