PB1194 - 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

Tuesday, July 12, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

Hanny Al-Samkari, MD

Assistant Professor of Medicine
Harvard Medical School
Boston, Massachusetts, United States

Co-Author(s)

DJ

Debbie Jiang

Hematologist
University of Washington
Seattle, Washington, United States
Terry Gernsheimer, MD

Hematologist
University of Washington
Seattle, Washington, United States
HL

Howard Liebman

Hematologist
University of Southern California-Keck School of Medicine
Los Angeles, California, United States
SL

Susie Lee

Hematologist
University of Southern California-Keck School of Medicine
Los Angeles, California, United States
CB

Chelsea Bernheisel

Medical Affairs Manager
Sobi, Inc.
Durham, North Carolina, United States
SK

Scott Kolodny

Senior Medical Director
Sobi, Inc.
Durham, North Carolina, United States
MW

Matthew Wojdyla

Associate Medical Director
Sobi, Inc.
Durham, North Carolina, United States
MV

Michael Vredenburg

Vice President, Medical Affairs
Sobi, Inc.
Durham, North Carolina, United States
Adam Cuker, MD, MS

Associate Professor
Department of Medicine and Department of Pathology & Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
Philadelphia, Pennsylvania, United States

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.