Abstract

Abstract 21

Background:

A number of studies have examined the effect of various platelet (plt) characteristics on the efficacy of plt transfusion(tx) including; source (apheresis platelets [AP] vs pooled platelets [PP]), plt ABO matching (identical [ID], minor mismatch [Min], major mismatch [Maj]), and duration of plt storage. These studies have focused on post transfusion plt counts with some evidence to support that there are differences in plt recovery based on these factors. These studies have not however examined the effect of these factors on the clinical outcome of bleeding.

Methods:

The PLADO study enrolled subjects with thrombocytopenia caused by stem cell transplantation (SCT) or chemotherapy into a blinded RCT of three different dosing strategies (lower, medium, and higher dose plt tx) to assess the effect of dose on the primary outcome of bleeding. Patients could receive either AP or PP with an attempt to keep patients on the same type plts. ABO selection and duration of storage were left to local practices. Patients were assessed daily for bleeding and, if present, assigned a WHO grade 2-4. A time to event analysis strategy was used with the outcome defined as the number of days from the first platelet transfusion to first date of bleeding. Subjects were censored on the first date they received a plt tx which differed from the first plt tx for the characteristic of interest. Analyses used Cox proportional hazard models with an adjustment for treatment group.

Results:

1351 patients were enrolled of which 1272 actually received a plt tx. 489 (38%) patients were excluded (41 given HLA selected plts, 421 with WHO Grade 2 or higher bleeding before or on the day of the first plt tx, and 27 with missing data) leaving 783 evaluable patients. The platelet source did not affect the time to first grade 2 or higher bleeding. Duration of platelet storage did not affect time to first grade 2 or higher bleeding . Because few patients received platelets stored for fewer than 3 days or more than 5 days, the analysis is shown for 3, 4 or 5 days of storage. ABO matching status did not affect time to first grade 2 or higher bleeding. A multi-predictor model using all 3 characteristics and treatment arm showed that none was significantly related to the time to grade 2 or higher bleeding.

Table 1.

Platelet characteristics as a predictor of bleeding

Characteristic Bleeding endpoint p value* Hazard ratio* 95%CI* 
PP vs AP ≥grade 2 0.55 1.07 (0.85, 1.35) 
PP vs AP ≥grade 3 0.27 0.70 (0.37, 1.32) 
3 vs 5 days ≥grade 2 0.55 0.87 (0.56, 1.37) 
4 vs 5 days ≥grade 2 0.45 0.85 (0.56, 1.29) 
Min vs ID ≥grade 2 0.21 0.73 (0.45, 1.20) 
Maj vs ID ≥grade 2 0.26 0.83 (0.60, 1.15) 
Characteristic Bleeding endpoint p value* Hazard ratio* 95%CI* 
PP vs AP ≥grade 2 0.55 1.07 (0.85, 1.35) 
PP vs AP ≥grade 3 0.27 0.70 (0.37, 1.32) 
3 vs 5 days ≥grade 2 0.55 0.87 (0.56, 1.37) 
4 vs 5 days ≥grade 2 0.45 0.85 (0.56, 1.29) 
Min vs ID ≥grade 2 0.21 0.73 (0.45, 1.20) 
Maj vs ID ≥grade 2 0.26 0.83 (0.60, 1.15) 
*

Cox proportional hazard model, adjusted for treatment arm

Conclusion:

Platelet characteristics including source (AP vs PP), duration of storage for 3 to 5 days, and ABO matching, do not affect the outcome of time to bleeding in patients with SCT or chemotherapy receiving prophylactic platelet transfusions.

Disclosures:

Triulzi:Fenwal: Consultancy, Membership on an entity's Board of Directors or advisory committees. Ness:Northfield Laboratories: Consultancy, Membership on an entity's Board of Directors or advisory committees; Caridian: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Author notes

*

Asterisk with author names denotes non-ASH members.