title: A phase II, open-label, sequential-cohort, dose-escalation study of romiplostim in Japanese patients with chronic immune thrombocytopenic purpura.
abstract: 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 microg/kg) subcutaneously on days 1 and 8 of the dose-escalation phase. Patients who achieved platelet responses (doubling of baseline platelet counts to > or =50 x 10(9)/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 > or =50 x 10(9)/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 microg/kg was recommended for phase III evaluation of romiplostim in Japanese patients with chronic ITP.
authors: Tokai University Hospital, Isehara, Japan.
authors: Yukari
authors: Y
authors: Shirasugi
authors: Tokai University Hospital, Isehara, Japan.
authors: Kiyoshi
authors: K
authors: Ando
authors: Hokkaido University Hospital, Sapporo, Japan.
authors: Satoshi
authors: S
authors: Hashino
authors: Tsukuba University Hospital, Tsukuba, Japan.
authors: Toshiro
authors: T
authors: Nagasawa
authors: Osaka University Hospital, Suita, Japan.
authors: Yoshiyuki
authors: Y
authors: Kurata
authors: Kansai Medical University Takii Hospital, Moriguchi, Japan.
authors: Yuji
authors: Y
authors: Kishimoto
authors: Hiroshima Red Cross Hospital and Atomic-Bomb Survivors Hospital, Hiroshima, Japan.
authors: Koji
authors: K
authors: Iwato
authors: Amgen KK, Tokyo, Japan.
authors: Tomoko
authors: T
authors: Ohtsu
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320-1799, USA. dberger@amgen.com.
authors: Dietmar P
authors: DP
authors: Berger
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D002352:Carrier Proteins / Q000008:administration & dosage* / Q000009:adverse effects; D002908:Chronic Disease; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000188:drug therapy* / Q000208:ethnology; D011961:Receptors, Fc / Q000008:administration & dosage*; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage* / Q000009:adverse effects; D034061:Thrombopoiesis / Q000187:drug effects*; D013926:Thrombopoietin; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D002352:Carrier Proteins; D011961:Receptors, Fc; D011993:Recombinant Fusion Proteins; D013926:Thrombopoietin; C488777:romiplostim