Assessment of clinical effectiveness of 3 buffy coat-derived platelet concentrates as compared to the standard 5 buffy coat-derived platelet concentrates in hemato-oncology patients

Platelet concentrates are given to patients with thrombocytopenia caused in
part by the treatment of their hemato-oncologic disease. Currently, platelet
concentrates for adults are prepared by pooling the platelet-containing buffy
coats from five donors. Studies have shown that when patients receive platelet
concentrates with a lower dose, they will have more transfusions but will
overall receive fewer platelets. THis is probably beneficial for the patient,
because donor exposure will be lower. A lower donor exposure will probably lead
to a lower chance of developing HLA antibodies, which in turn may prevent
refractiroiness to platelet transfusions. Refractoriness is associated with an
increased risk of mortality due to bleeding.
The cited studies used a different kind of platelet concentrates than used in
the Netherlands, namely collected by aphereis from a single donor. In the
Netherlands, pools of five donations are made, which will affect donor
exposure.
In addition to lowering donor exposure, we suspect additional benefits from
treating patients with a lower platelet dose, as explained in more detail in
the study protocol. However, in order to switch to a new platelet product, it
needs to be demonstrated that the clinical effectiveness is about as good as
that of the current standard for the purpose for which it is used, namely
prevention or stopping of bleeding.

The objective of the study is to determine whether platelet concentrates from 3
buffy coats are non inferior to the current 5 buffy coats. We will investigate
whether the percentage of days with a bleeding grade 1b+2 (mild, clinically non
significant bleeds and higher) according to the Bleeding Severity Measurement
Score grading scale. Donor exposure will be measured by determining from how
many buffy coats the platelet concentrates were derived. In the patient's
blood, we will determine whether HLA antibodies have formed. Using the
Corrected Count Increment (CCI) we will determine whether the patient has
become refractory.

Patients will be randomized to receive 3- or 5-buffy coat platelet concentrates
during the period of treatment of their disease. There will be a daily check
whether bleeds occurred, and the percentage of days with a grade 1b+2 bleed
will be compared between groups.

Patients in the study group will be treated with platelet concentrates prepared
from 3 buffy coats, patients in the control group will be treated with standard
platelet concentrates from 5 buffy coats.

The patients will be treated with platelet transfusions anyway, just in the
study group the concentrates will be smaller. We expect that the patient will
be transfused more often, but will receive fewer platelets overall. We expect
that any risks will be averaged out.