Objective: To determine if platelets treated for pathogen inactivation and stored for 6 to 7 days are safe and effective compared to platelets collected by the same method, stored for the same amount of time and not treated for pathogen inactivation.

Although the European Commission directive 2004/33/EC states that platelet preparations may be stored for 7 days in conjunction with detection or reduction of bacterial contamination, most blood centers store platelets for only 4 or 5 days. Extending the storage time could greatly improve platelet availability for patients while decreasing wastage of this limited resource.

Inclusion Criteria:

• At least 16 years old
• Written informed consent
• Thrombocytopenia, or expected to develop thrombocytopenia requiring platelet transfusion within 15 days of randomization
• Undergoing one haematopoietic stem cell transplantation and/or admitted for treatment of acute or chronic leukaemia, lymphoma, multiple myeloma or myelodysplasia

Exclusion Criteria:

• Refractoriness to platelet transfusion
• Immune-mediated thrombocytopenia, thrombotic thrombocytopenic purpura, or hemolytic uremic syndrome
• Use of IL-11 (Neumega®) or other investigational platelet growth factor
• Disseminated intravascular coagulation (DIC)
• Clinically or radiologically detectable splenomegaly
• Previous participation in the study