Efficacy of Romiplostim in Treatment of SAA in Adults Previously Untreated With or Refractory to Immunosuppressive Therapy

Two Arm Bridging Study to Evaluate the Efficacy of Romiplostim in the Treatment of Adult Severe Aplastic Anemia Participants Who Are Either Previously Untreated With IST or Refractory to IST

Romiplostim has been used in clinical trials for the treatment of severe and very severe aplastic anemia (SAA/vSAA) in Asian participants who are either previously untreated with immunosuppressive therapy (IST) or refractory to IST. This study will evaluate the efficacy of romiplostim in the treatment of participants with SAA/vSAA.

The primary objectives of this study are to:

Arm 1: Evaluate the efficacy of romiplostim and IST in adult SAA/vSAA participants who are previously untreated with IST (1L)

Arm 2: Evaluate the efficacy of romiplostim treatment in adult SAA/vSAA participants who are refractory to IST (2L+)

Inclusion Criteria:

• Age ≥ 18 years at time of enrollment
• Diagnosis of SAA/vSAA confirmed by blood, bone marrow, and cytogenetic studies
• An Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 1 at screening
• Arm 1 only: participant requires initial treatment for SAA/vSAA, no matched related donor is available for allogenic hematopoietic cell transplantation (HCT) and will begin IST with antithymocyte globulin and CsA
• Arm 2 only: refractory to at least one course of immunosuppressive therapy including horse or rabbit ATG; or ineligible for ATG treatment and refractory to CsA

Exclusion Criteria:

• Diagnosed as having congenital aplastic anemia (AA) (Fanconi anemia, congenital dyskeratosis, etc)
• History of other malignancy within the past 5 years, with exceptions.
• Aplastic anemia with hemolytic paroxysmal nocturnal hemoglobinuria (PNH) (hemolytic predominant is defined as lactate dehydrogenase (LDH) > 1.5 x the upper limit of site normal
• Arm 1 only: Previously treated with ATG, CsA, or Alemtuzumab
• Previously treated with PEGylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), recombinant human thrombopoietin protein (TPO), romiplostim and other TPO-receptor agonist (eltrombopag, etc)
• Patients who are eligible for allogenic HCT and have an available matched related donor