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Management of chronic immune thrombocytopenia (cITP) aims not only to increase and maintain platelet counts in safe levels, but also to improve quality of life. Thrombopoietin agonists eltrombopag and romiplostim have been approved in refractory ITP. The lack of randomized studies allows only for real-world data comparison on the two agents.

In the present study we evaluate and compare long-term efficacy and safety of etrombopag and romiplostim in clinical practice and assess the switching feasibility between the two agonists.

Treatment with thrombopoietin agonists was initiated in 20 adult patients (pts) with refractory cITP between June 2011-2016. Patients resistant or intolerant to the first agonist switched to the second one. Complete response (CR) was defined as a platelet count of ≥100x10⁹/L.

Eltrombopag was administered in 15 pts, 6 male:9 female with a median age of 46 years (19-76 yrs) for 13 months (1.4-54 mo). Patients had received a median of 1 previous treatment (range 1-7): corticosteroids (15/15), intravenous immunoglobulin (5/15), rituximab (2/15), vincristine (1/15), cyclosporine (2/15), romiplostim (2/15), danazol (1/15) and splenectomy (1/15). Before eltrombopag treatment, the majority (8/15) showed grade 4 (WHO) thrombocytopenia. Initial dose was 50 mg and increased to 75 mg daily in 3/15 pts and in combination with corticosteroids that were gradually tapered by the 5^th week in 12/15. Median platelets value by the 2^nd week of administration was 140x10⁹/L (5-450 x10⁹/L); whereas, by the 4^th week increased to 185x10⁹/L (16-500x10⁹/L). At the end of follow-up, all patients but one achieved CR with median platelets of 145x10⁹/L (60-400 x10⁹/L). Regarding adverse events, 1/15 pt presented hemolytic anemia, 1/15 pt hepatotoxicity grade 2 with episodes of thrombocytopenia grade 4 and 1/15 pt pulmonary embolism during the second month of treatment. The latter 2 pts switched to romiplostim.

Romiplostim was administered in 9 pts, 4 male:5 female aged 44 years (33-63 yrs) for 40.7 months (22.4-60.1). They had received a median of 3 previous treatments (range 1-8): corticosteroids (9/9), intravenous immunoglobulin (6/9), rituximab (6/9), vincristine (2/9), cyclosporine (2/9), eltrombopag (2/9), danazol (1/9) and splenectomy (2/9). The majority (5/9) presented thrombocytopenia grade 4 before romiplostim. Median platelets number by the 2^nd week of administration was 50x10⁹/L (8-140 x10⁹/L); whereas, by the 4^th week increased to 115x10⁹/L (20-400x10⁹/L). At the end of follow-up, 6/9 patients achieved CR with median platelets at 145x10⁹/L (110-400x10⁹/L). All patients received concomitant steroid treatment that was gradually tapered and stopped in 6/9 pts. 2/9 pts switched to eltrombopag due to thrombocytopenia grade 3 and 1/9 pt to danazol and low-dose steroids achieving CR. No adverse events associated with romiplostim treatment were reported.

No significant differences were found between the 2 treatment groups. All 4 patients that switched to the other agonist achieved CR without adverse events.

Our real-world data suggest that both eltrombopag and romiplostim are safe, well tolerated and highly effective in refractory cITP and furthermore, switching to another agonist is safe and effective. Future studies will determine predisposing factors for adverse events and more accurate classification of patients that will allow for better treatment guidance.