Abstract Number: PB1194
Meeting: ISTH 2022 Congress
Theme: Platelet Disorders, von Willebrand Disease and Thrombotic Microangiopathies » Acquired Thrombocytopenias
Background: Avatrombopag is an oral thrombopoietin receptor agonist (TPO-RA) approved for treatment of immune thrombocytopenia (ITP) without food-type restrictions. Data comparing effectiveness of avatrombopag following treatment with other TPO-RAs in primary ITP (pITP) and secondary ITP (sITP) is limited.
Aims: Evaluate avatrombopag response in pITP and sITP after switching from other TPO-RAs.
Methods: We retrospectively evaluated all adults with ITP switched from eltrombopag or romiplostim to avatrombopag at four U.S. centers from July 2019 through December 2020. Reasons for switch included effectiveness (n=14), convenience (n=23) and adverse events (n=7). Response was defined as a platelet count (PC) ≥30,000/uL (R30) and ≥50,000/uL(R50) with loss of response as two consecutive PCs, at least 7 days apart, < 30,000/uL and < 50,000/uL respectively. The proportion of time with a defined platelet response while on avatrombopag was measured.
Results: 44 patients were included, 25 (57%) with pITP and 19 (43%) with sITP (Table 1). Causes of sITP included hepatitis C, chronic lymphocytic leukemia, systemic lupus erythematosus (n=3 each), autoimmune hepatitis, B-cell lymphoma, Evan’s syndrome, HIV, CREST syndrome, rheumatoid arthritis, relapsing polychondritis, antiphospholipid antibody syndrome, CVID, not listed (n=1 each).
42/44 (96%) achieved an R30 with avatrombopag including 23/25 (92%) pITP patients and 19/19 (100%) sITP patients. pITP patients and sITP patients maintained an R30 91.5% and 85% of their time on avatrombopag, respectively. Table 2 shows additional durability of response data with avatrombopag.
Conclusion(s): In a heavily pretreated, chronic ITP population switched from another TPO-RA to avatrombopag, nearly all (96%) patients achieved a platelet response. Response and proportion of time with response in the observation period were similar, regardless of primary or secondary ITP diagnosis. This represents the first evidence reported regarding durability of response with avatrombopag in secondary ITP; more data on the effectiveness and safety of avatrombopag in patients with secondary ITP are needed.
To cite this abstract in AMA style:
Al-Samkari H, Jiang D, Gernsheimer T, Liebman H, Lee S, Bernheisel C, Kolodny S, Wojdyla M, Vredenburg M, Cuker A. Platelet Response to Avatrombopag Following Switch from Eltrombopag or Romiplostim in Primary vs. Secondary Immune Thrombocytopenia: A Multicenter Study of U.S. ITP Referral Centers [abstract]. https://abstracts.isth.org/abstract/platelet-response-to-avatrombopag-following-switch-from-eltrombopag-or-romiplostim-in-primary-vs-secondary-immune-thrombocytopenia-a-multicenter-study-of-u-s-itp-referral-centers/. Accessed March 21, 2024.« Back to ISTH 2022 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/platelet-response-to-avatrombopag-following-switch-from-eltrombopag-or-romiplostim-in-primary-vs-secondary-immune-thrombocytopenia-a-multicenter-study-of-u-s-itp-referral-centers/