Efficacy of Mirasol-treated Apheresis Platelets in Patients With Hypoproliferative Thrombocytopenia

This is a prospective, multi-center, controlled, randomized, non-inferiority study to evaluate the clinical effectiveness of Conventional versus Mirasol-treated apheresis platelets in subjects with hypoproliferative thrombocytopenia who are expected to have platelet count(s) ≤ 10,000/μL requiring ≥ 2 platelet transfusions.

Patients will be randomized 1:1 to Mirasol-treated platelets (test platelets) or to conventional, untreated platelets (control platelets). The blood centers will collect the apheresis donor platelets and supply the test platelets to the hospital sites for transfusion into patients. Hospital sites will order control platelets as per their normal process, from their standard vendor.

The target population for the MIPLATE study are patients with hematologic malignancies with hypoproliferative thrombocytopenia who are expected to have platelet (PLT) count(s) of ≤ 10,000/μL requiring ≥ 2 PLT transfusions.

The primary objective of MIPLATE is to determine if the hemostatic efficacy of Mirasol-treated plasma stored Trima Accel® Aph PLTs are non-inferior to Conventional plasma stored Aph PLTs in subjects with hypoproliferative thrombocytopenia requiring PLT transfusions. The secondary objectives include comparing other efficacy and safety endpoints between the treatment groups.

Subjects with hematologic malignancies with hypoproliferative thrombocytopenia are anticipated to experience a "transfusion episode" where they will require PLT transfusion support until bone marrow recovery. During this period all PLT transfusions required for a study subject will be given according to the subject's treatment allocation for 28 days after the initial PLT transfusion OR until transfusion independence (10 days without PLT transfusion) prior to Day 28.

Additionally, serum samples for HLA antibody testing will be collected on Days 14, 28 and 56.

At a minimum, the initial post-randomization prophylactic PLT transfusion will be initiated for a PLT count ≤ 10,000/µL. Thereafter, indications for PLT transfusions may be PLT count-related prophylaxis, intervention-related prophylaxis, or therapeutic (treatment of active bleeding) as determined by the treating physician(s). The indication(s) for the transfusion(s) will be captured.

Eligibility Criteria:
Inclusion Criteria:

1. Weight \> 10 kg (22 lbs)
2. Subject has a hematologic malignancy with hypoproliferative thrombocytopenia and is expected to have PLT count(s) ≤ 10,000/µL requiring ≥ 2 PLT transfusions
3. Laboratory results within 5 days prior to anticipated initiation of the first post randomization PLT transfusion:

   1. Prothrombin time (PT) and/or international normalized ratio (INR) ≤ 1.3 × the upper limit of normal (ULN)
   2. Activated partial thromboplastin time (aPTT) ≤ 1.3 × ULN
   3. Fibrinogen ≥ 100 mg/dL
4. Women of childbearing potential must have a negative pregnancy test and agree to practice a medically acceptable contraception regimen for the study duration. Women who are postmenopausal for at least 1 year (\> 12 months since last menses) or are surgically sterilized do not require this test
5. IC from the subject or assent from the subject and consent from a parent or guardian, if the subject is \< 18 years of age

Exclusion Criteria:

1. Treatment with pathogen-reduced blood products within previous 6 months
2. Subject has been previously enrolled in this study and received at least 1 per protocol PLT transfusion
3. a.) Subject is receiving therapeutic doses of antiplatelet agents, antifibrinolytics, and/or PLT specific growth factors within 10 days prior to randomization or b.) Subject is receiving therapeutic doses of anticoagulant, pro-coagulant or antithrombotic agents within 10 days prior to randomization. Subjects can be included if receiving the following: prophylactic dosing of anticoagulants (heparin, any low molecular weight heparin, enoxaparin, or fondaparinux), anticoagulants/thrombolytic agents used to maintain or re-establish the patency of catheters (heparin flushes or tissue-plasminogen activase \[TPA\], therapeutic doses of anticoagulants with a half-life of \< 24 hours if it will be discontinued at least 24 hours prior to the first study transfusion, single periprocedural doses of anticoagulants with a half-life of \< 24 hours or low dose aspirin (81 mg per day)
4. Subject has ≥ grade 2 bleeding at the time of randomization
5. Planned administration of bedside LR PLT transfusion(s)
6. Presently with or a history of acute promyelocytic leukemia (APML), idiopathic thrombocytopenic purpura (ITP), thrombotic thrombocytopenic purpura (TTP), or hemolytic uremic syndrome (HUS)
7. HLA and/or HPA-alloimmunization and/or platelet refractory as determined by the investigator
8. Hypersplenism as evidenced by splenomegaly based on investigator assessment at baseline
9. History or diagnosis of a disease affecting hemostasis
10. Currently taking, or participating in a clinical study involving PLT substitutes, PLT growth factors, or pharmacologic agents intended to enhance (i.e, antifibrinolytic agents) or decrease PLT hemostatic function
11. Acute or chronic medical disorder that, in the opinion of the investigator, would impair the ability of the subject to receive protocol treatment
12. Subject is pregnant or lactating
13. Inability of the subject to comply with study procedures and/or follow-up