One thrombopoietin receptor agonist (TPO-RA) may help patients with immune thrombocytopenia (ITP), whereas another may not. Patients who converted from romiplostim or eltrombopag to avatrombopag, a newer oral TPO-RA, have had mixed results, according to the little data available. At four tertiary ITP referral centers in the United States, researchers conducted a retrospective observational analysis of persons with ITP who switched from eltrombopag or romiplostim to avatrombopag. The study comprised 44 patients with an average ITP duration of 8.3 years and a median (range) of four previous ITP therapies. A platelet response (≥50 × 109/l) was reached in 41/44 patients (93%) and a full response (≥100 × 109/l) was achieved in 38/44 patients (86%) on avatrombopag. 

The median platelet count on eltrombopag or romiplostim was 45 × 109/l vs 114 × 109/l on avatrombopag (P<0.0001); in patients switched for the ineffectiveness of romiplostim/eltrombopag, it was 28 × 109/l vs 88 × 109/l  on avatrombopag (P=0.025). About 57% of patients who were on concomitant ITP drugs before switching stopped taking them after switching, including 63% of patients on chronic corticosteroids. Avatrombopag was efficacious after romiplostim or eltrombopag therapy in a strongly pretreated chronic ITP population, with significant response rates even in patients who had not responded to a previous TPO-RA.