International Journal of Hematology

, Volume 90, Issue 2, pp 157–165 | Cite as

A phase II, open-label, sequential-cohort, dose-escalation study of romiplostim in Japanese patients with chronic immune thrombocytopenic purpura

  • Yukari Shirasugi
  • Kiyoshi Ando
  • Satoshi Hashino
  • Toshiro Nagasawa
  • Yoshiyuki Kurata
  • Yuji Kishimoto
  • Koji Iwato
  • Tomoko Ohtsu
  • Dietmar P. Berger
Original Article


This phase II, multicenter, open-label, sequential-cohort, dose-escalation study was designed to evaluate the safety and efficacy of romiplostim, a novel peptibody that increases platelet production, in Japanese patients with chronic immune thrombocytopenic purpura (ITP). Sequential cohorts of four patients each received romiplostim (1, 3, or 6 μg/kg) subcutaneously on days 1 and 8 of the dose-escalation phase. Patients who achieved platelet responses (doubling of baseline platelet counts to ≥50 × 109/L) continued romiplostim weekly during the treatment-continuation phase. Romiplostim produced dose-dependent increases in mean and peak platelet counts. Five patients received romiplostim during the treatment-continuation phase, with platelet counts ≥50 × 109/L maintained in approximately half of the weekly assessments. Romiplostim was well tolerated. No severe, serious, or life-threatening adverse events were reported. No binding antibodies to romiplostim or thrombopoietin were detected. Romiplostim is safe and well tolerated in Japanese patients with chronic ITP and is effective in producing platelet count increases, consistent with the results from studies in non-Japanese patients. On the basis of these findings, a starting dose of 3 μg/kg was recommended for phase III evaluation of romiplostim in Japanese patients with chronic ITP.


Immune thrombocytopenic purpura Romiplostim Thrombopoiesis Platelet production 


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Copyright information

© The Japanese Society of Hematology 2009

Authors and Affiliations

  • Yukari Shirasugi
    • 1
  • Kiyoshi Ando
    • 1
  • Satoshi Hashino
    • 2
  • Toshiro Nagasawa
    • 3
  • Yoshiyuki Kurata
    • 4
  • Yuji Kishimoto
    • 5
  • Koji Iwato
    • 6
  • Tomoko Ohtsu
    • 7
  • Dietmar P. Berger
    • 8
  1. 1.Tokai University HospitalIseharaJapan
  2. 2.Hokkaido University HospitalSapporoJapan
  3. 3.Tsukuba University HospitalTsukubaJapan
  4. 4.Osaka University HospitalSuitaJapan
  5. 5.Kansai Medical University Takii HospitalMoriguchiJapan
  6. 6.Hiroshima Red Cross Hospital and Atomic-Bomb Survivors HospitalHiroshimaJapan
  7. 7.Amgen KKTokyoJapan
  8. 8.Amgen Inc., One Amgen Center DriveThousand OaksUSA

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