ORIGINAL RESEARCH
Transfusion of pathogen-reduced platelet components without
leukoreduction
Joycelyn Sim,1 Wai Chiu Tsoi,2 Cheuk Kwong Lee,2 Rock Leung,1 Clarence C. K. Lam,1 Claudia Koontz,3
Amy Yingjie Liu,3 Norman Huang,3 Richard J Benjamin,3 Hans J. Vermeij,3 Adonis Stassinopoulos ,3
Laurence Corash ,3 and Albert K. W. Lie1
BACKGROUND: Leukoreduction (LR) of platelet
concentrate (PC) has evolved as the standard to mitigate
risks of alloimmunization, clinical refractoriness, acute
transfusion reactions (ATRs), and cytomegalovirus
infection, but does not prevent transfusion-associated
graft-versus-host disease (TA-GVHD). Amotosalen–
ultraviolet A pathogen reduction (A-PR) of PC reduces
risk of transfusion-transmitted infection and TA-GVHD.
In vitro data indicate that A-PR effectively inactivates
WBCs and infectious pathogens.
STUDY DESIGN AND METHODS: A sequential
cohort study evaluated A-PR without LR, gamma
irradiation, and bacterial screening in hematopoietic stem
cell transplant (HSCT) recipients. The first cohort
received conventional PC (control) processed without
LR, but with gamma irradiation and bacterial screening.
The second cohort received A-PR PC (test) processed
without: LR, bacterial screening, or gamma irradiation.
The primary efficacy outcome was the 1-hour corrected
count increment. The primary safety outcome was
treatment-emergent ATR. Secondary outcomes included
clinical refractoriness, and 100-day status for
engraftment, TA-GVHD, HSCT-GVHD, infections, and
mortality.
RESULTS: Mean corrected count increment (× 103) of
33 test PC recipients was similar (18.9 8.8
vs. 16.6 8.4; p = 0.296) to that of 31 control PC
recipients. Test recipients had a reduced, but
nonsignificant, incidence of ATR (test = 9.1%,
Control = 19.4%; p = 0.296). The frequencies of clinical
refractoriness (0 of 33 vs. 4 of 31 patients) and refractory
transfusions (6.6% vs. 19.3%) were lower in the test
cohort (p = 0.05 and 0.02), respectively. No patient in
either cohort had TA-GVHD. Day 100 engraftment,
HSCT-GVHD, mortality, and infectious disease
complications were similar between cohorts.
CONCLUSIONS: This study indicated that A-PR PC
without LR, gamma irradiation, or bacterial screening is
feasible for support of HSCT.
H
ematopoietic stem cell transplant (HSCT) recipients
require platelet concentrate (PC) transfusion for support of hypoplastic thrombocytopenia.1–3 Donors are
tested for a limited panel of viruses, and PCs are
screened for bacterial contamination and irradiated to prevent
transfusion-associated graft-versus-host disease (TA-GVHD).
To mitigate the risks of acute transfusion reactions (ATRs),
alloimmunization, clinical refractoriness, and cytomegalovirus
(CMV) infection, PCs are commonly, but not universally, prepared
with leukoreduction (LR).4–6 These interventions require separate
procedures, and while reducing the risk of transfusion adverse
events (AEs), they do not provide complete protection from ATRs
or CMV transfusion-transmitted infection (TTI)7–10 or the residual
risk of window period infections, untested pathogen infections,
and emerging pathogen infections.11–13
ABBREVIATIONS: AEs = adverse events; A-PR = amotosalen–
ultraviolet A pathogen reduction; ANCs = absolute neutrophil
counts; ATRs = acute transfusion reactions; CCI = corrected count
increment; CIs = confidence intervals; HKRCBTS = Hong Kong Red
Cross Blood Transfusion Service; HSCT = hematopoietic stem cell
transplant; LR = leukoreduction; PC = platelet concentrate; SAEs =
serious adverse events; TA-GVHD = transfusion-associated graftversus-host disease; TTI = transfusion-transmitted infection.
From the 1Queen Mary Hospital and University of Hong Kong, Pok
Fu Lam; 2Hong Kong Red Cross Blood Transfusion Service, Yau Ma
Tei, Hong Kong; and the 3Cerus Corporation, Concord, California.
Address reprint requests to: Laurence Corash, MD, Cerus
Corporation, 2550 Stanwell Drive, Concord, California 94520 USA;
e-mail: lcorash@cerus.com
This is an open access article under the terms of the Creative
Commons Attribution-NonCommercial-NoDerivs License, which
permits use and distribution in any medium, provided the original
work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Received for publication September 28, 2018; revision received
February 7, 2019, and accepted February 9, 2019.
doi:10.1111/trf.15269
© 2019 The Authors. Transfusion published by Wiley
Periodicals, Inc. on behalf of AABB.
TRANSFUSION 2019;00;1–9
TRANSFUSION 1
SIM ET AL.
Pathogen reduction of PC with amotosalen and UVA light
(A-PR; INTERCEPT, Cerus Corporation) mitigates multiple risks
of PC transfusion with a single procedure to inactivate viruses,
bacteria, protozoa, and leukocytes contaminating PCs. This
technology was introduced in Europe in 2003.14,15 From inception, A-PR replaced PC bacterial culture screening, CMV serology, and gamma irradiation, but due to the established practice
of leukocyte reduction, it was used with LR. Postmarketing experience provided evidence indicating A-PR efficacy for the prevention of transfusion-related sepsis and TA-GVHD.16–18 A-PR with
leukoreduced apheresis PC was licensed by the US Food and
Drug Administration in 2014,19 in 2016 A-PR replaced testing for
Zika virus,20 demonstrated efficacy to inactivate emerging
pathogens,21 and is used without bacteria screening.22
A-PR inactivates WBC-associated CMV23 and inhibits WBC
antigen presentation24 WBC cytokine synthesis,25 and T-cell proliferation.26,27 Based on these observations and 10 years of experience showing that A-PR reduced the risk of transfusion-related
sepsis and TA-GVHD, we postulated that A-PR could be used
without LR. As of 2013, the Hong Kong Red Cross Blood Transfusion Service (HKRCBTS) had not implemented routine
leukoreduction for conventional whole blood PCs. The HKRCBTS
and Queen Mary Hospital decided to evaluate the potential to
transition from the current type of PCs, platelet-rich plasma PC
suspended in 100% plasma, to A-PR PC in plasma with platelet
additive solution without leukoreduction of whole blood PC. We
designed a prospective, sequential cohort study in HSCT recipients to characterize the efficacy and safety of A-PR PC without
leukoreduction, bacterial screening, or gamma irradiation compared to conventional nonleukoreduced platelet-rich plasma PC,
the current HKRCBTS standard of care, to evaluate the potential
adoption of A-PR PC without LR into routine practice.
MATERIALS AND METHODS
General study design
We conducted an open-label, prospective, sequential cohort
study to enroll approximately 30 HSCT recipients in each cohort.
The sequential design facilitated PC inventory management and
provided baseline data to characterize corrected count increment
(CCI) responses with conventional PC. Cohorts were case matched for primary disease and type of HSCT at a single HSCT clinical center (Queen Mary Hospital, Hong Kong). All PCs were
provided by the HKRCBTS. The same primary care physicians
managed both cohorts with similar standards of care. The novel
intervention was A-PR PC without LR, bacterial culture screening,
or gamma irradiation compared to conventional PC without LR,
but with bacterial culture screening and gamma irradiation. Both
types of PC were licensed for use in Hong Kong. The active transfusion period was up to 28 days or transfusion of up to 5 PCs, with
AE monitoring for 7 days after the last PC and follow-up 100 days
after HSCT. Patients gave written informed consent to participate
in the study, which was conducted in compliance with Good Clinical Practice according to the International Conference on
2 TRANSFUSION
Harmonization guidelines, and local ethical committee and legal
requirements consistent with the Declaration of Helsinki.
Platelet components
All donors were tested for human immunodeficiency virus, hepatitis B virus, and hepatitis C virus per HKRCBTS standards. Test
PCs were prepared from citrate-phosphate-dextrose solution
whole blood as buffy coat platelets with platelet additive solution
(SSP+, Macopharma). Five A-, B-, and O-matched buffy coat
platelets suspended in nominal 35% plasma and 65% SSP+ were
pooled and treated with the INTERCEPT System for platelets by
the end of the first postcollection day per manufacturer’s
instructions to produce 3 × 1011 or more platelets per PC.19 Test
PCs were not leukoreduced, screened for bacteria, or gamma
irradiated, and were stored for up to 5 days on a shaker at 22 to
24 C. Pooled test PC contained approximately 5 × 108 WBCs.28
Control PCs suspended in plasma, the current HKRCBTS
standard of care, were prepared from citrate-phosphatedextrose solution whole blood by the platelet-rich plasma
method without leukoreduction. Five A-, B-, and O-matched
concentrates in 100% plasma were pooled without LR to yield
3 × 1011 or more platelets per PC. Control PCs were screened for
bacteria with the short term bacterial culture method of
HKRCBTS.29 All control PCs were gamma irradiated (2,500 cGy)
and were stored up to 5 days on a shaker at 22 to 24 C. Control
pooled PCs contained approximately 5 × 109 leukocytes.28
Study procedures
HSCT patients aged 18 years or older expected to require PC
were screened for inclusion. Exclusion criteria were prior documented history of clinical refractoriness to platelet transfusion
(two successive 1-hour CCI < 5.0 × 103), immune thrombocytopenia, or disorders confounding 1-hour CCI determination. For
both cohorts, a transfusion threshold of 10 × 109/L was specified for clinically stable patients unless adjusted to 20 × 109/L
for suspected sepsis. Patients were not screened for HLA antibody at study entry. Patients enrolled in the control cohort were
not later reenrolled in the test cohort. Patients enrolled in the
test cohort were supported exclusively with A-PR PC. Patients
in both cohorts were monitored for AEs during each 48-hour
period after PC transfusions, and AEs related to PC transfusion
were classified as ATRs. After transfusion, all PC containers
were sealed and returned to the HKRCBTS. In the event of a
posttransfusion temperature increase of 1 C with rigors or 2 C
with or without rigors, the residual PC was cultured and patient
blood cultures obtained. For both cohorts, 100 to 120 days’
post-HSCT clinical follow-up was performed for health status,
engraftment, TA-GVHD, HSCT-GVHD, immune reconstitution,
and infectious AE.
Outcome measures
The primary efficacy outcome was the mean 1-hour CCI per
patient.30 Blood samples were obtained from 10 minutes to
4 hours after transfusion to allow a window for acquisition of
REPLACEMENT OF LEUKOREDUCTION
platelet counts. Secondary outcomes included the proportion
of patients with clinical refractoriness (defined as two successive transfusions with 1-hour CCI <5.0 × 103), and the proportion of transfusions in each cohort with 1-hour CCI less than
5.0 × 103. The primary safety outcome was the incidence of
ATR during 48 hours after each study transfusion. Patients in
both cohorts were monitored for all AEs in the first 48 hours
after each transfusion. Vital signs were measured before and
within 6 hours after each study transfusion. AEs attributed to
PC were classified as ATRs as defined in prior hemovigilance
studies.17 Patients were monitored for serious adverse events
(SAEs) per regulatory criteria31 and for mortality. AEs and
SAEs were classified by preferred term using the Medical Dictionary for Regulatory Activities, version 19.1.
Statistical analyses
The efficacy and safety of leukoreduced pooled buffy coat platelets prepared with A-PR were evaluated in prior randomized
controlled studies of patients with neoplastic hematology disorders.17,30,32 In view of prior clinical experience with A-PR PCs
over 10 years, this study was not designed with statistical power
to detect differences between cohorts but instead was designed
with at least 30 patients per cohort to detect potential signals of
impaired efficacy (1-hour CCI <5.0 × 103) and safety (TA-GVHD)
for PC prepared without leukoreduction and gamma irradiation.
The data consist of quantitative and qualitative descriptors of the
population transfused, the number of PC transfusions, the mean
patient 1-hour CCI, the proportion of patients with clinical
refractoriness, the proportion of transfusions with 1-hour CCI
less than 5.0 × 103, and quantification of the incidence and type
of observed ATRs, AEs, and SAEs during the active transfusion
period and 100-day follow up. All patients were analyzed on an
intent-to-treat basis. Point estimates with associated standard
errors and treatment differences were computed to provide qualitative comparisons. Descriptive analyses were conducted for
demographic and clinical variables. Continuous variables were
summarized by means and standard deviations and categorical
variables by frequencies and proportions based on nonmissing
data. Proportions were analyzed using Fisher’s exact test. Treatment differences between test and control PC recipients with
95% confidence intervals (CIs) for the differences were calculated
to provide clinical context. P values were computed for information. No adjustments were made for missing data.
In addition to the descriptive analyses, the CIs and CCI
endpoints were analyzed using a repeated-measures mixedeffects model to accommodate the longitudinal results over
repeated PC transfusions. For CI, the treatment cohort (test
vs. control), pretransfusion platelet count, patient weight, transfused dose, and platelet age were included as fixed effects, while
the individual patient was selected as the random effect. The
CCI endpoint was modeled in a similar fashion with the exception that patient weight and transfused dose were removed as
fixed effects since they were used in the CCI derivation. All
analyses were conducted with computer software (R, version
3.2.2; and SAS, version 9.4; SAS Institute).
RESULTS
The control cohort of 31 patients received 89 PCs. The test
cohort of 33 patients received 76 PCs. All 64 patients completed
the active transfusion period and the 100-day follow-up. Baseline population demographics for primary disease, HSCT stem
cell source, HSCT type (autologous/allogeneic), HSCT HLA
match (related donor, unrelated donor, mismatch) were similar
between cohorts except for the proportion of females and a longer average interval to first PC in the test cohort (Table 1). The
population consisted primarily of allogeneic HSCT recipients
prepared with myeloablative conditioning (control, 17 of 26 vs.
test, 23 of 27; Table S1). Prior PC transfusion exposure was
greater for the test cohort (Table 1). The duration of PC support,
number of transfused PCs, and average time of PC storage prior
to transfusion were similar between the cohorts (Table 2).
Efficacy outcomes
Mean platelet doses (× 1011) per transfusion were similar
between cohorts (test = 3.6 0.4 vs. control = 3.5 0.4;
Table 2). Mean pretransfusion platelet counts (× 109/L) were
low in both cohorts (Table 3; test = 15.3 11.4 vs. control =
11.1 6.7). The mean 1-hour CIs per patient (test = 42.5 21.8
vs. control = 36.5 19.2), and CCIs (test = 18.9 8.8
vs. control = 16.6 8.4) were not different (Table 3, and Fig. 1).
Analysis by the repeated-measures mixed-effects model demonstrated similar trends (Table 3). The point estimates for the
least squares mean treatment difference (test – control) for CI
and CCI were 6.8 (95% CI, −3.0 to 16.7) and 2.4 (95% CI, −1.9
to 6.6), respectively (Table 3). There were no substantial differences in 1-hour CCI for patients with and without HSCT-GVHD
or for autologous HSCT (Fig. 1). Four of 31 patients (12.9%) in
the control cohort developed clinical refractoriness to platelet
transfusions compared to 0 of 33 patients in the test cohort
(p = 0.05). Among the control cohort, 19.1% of PC transfusions
resulted in CCI responses less than 5.0 × 103 compared to 6.6%
of test PC transfusions (p = 0.02). Patients with HSCT-GVHD
may have poor responses to platelet transfusion.33 Thus, we
evaluated the 1-hour CCI in this subset of patients and observed
that all test cohort patients had mean CCI responses greater
than 5.0 × 103, indicative of an effective CCI,34 while two control
patients had mean CCI responses less than 5.0 × 103 (Table S2).
Safety outcomes
During the active transfusion period, ATRs were reported for
3 (9.1%) test and 6 (19.4%) control patients (p = 0.296)
(Table 4). All ATRs were of low severity. For test, 2 (6.1%) ATRs
consisted of urticaria and one (3.0%) with pyrexia. For control,
5 (15.6%) ATR consisted of urticaria and 1 (3.2%) of chills. In
both cohorts, all ATR resolved. During the active transfusion
period, no patients died, and none had TA-GVHD. AEs were
reported for 4 (12.1%) test and 13 (41.9%) control patients
TRANSFUSION 3
SIM ET AL.
TABLE 1. Study population patient demographics
Population demographics
Age (y)
Male (%)
BSA (m*)
ABO and Rh group and type
A (%)
B (%)
AB (%)
O (%)
Rh+ (%)
Primary disease
AL (%)
CL (%)
Lymphoma (%)
Other* (%)
HSCT source
PBSCs (%)
Bone marrow (%)
Autologous (%)
Allogeneic (%)
Related (%)
Unrelated (%)
HSCT HLA match status
Matched related
Matched unrelated
HLA mismatched (%)
Prior PC transfusion
Days to first study PC
Test
(33)
Control
(31)
Test-control
difference (95% CI)
p value†
43.3 12.2
18 (54.5%)
1.65 0.20
47.1 11.1
11 (35.5%)
1.60 0.16
−3.8 (−9.6 to 2.1)
NA
0.04 (−0.05 to 0.13)
0.201
0.401
0.344
7 (21.2%)
9 (27.3%)
2 (6.1%)
15 (45.5%)
32(97.0%)
7 (22.6%)
10 (32.3%)
2 (6.5%)
12 (38.7%)
31 (100.0%)
NA
NA
NA
NA
NA
0.941
21(63.6%)
2 (6.1%)
6 (18.2%)
4 (12.1%)
20 (64.5%)
1 (3.2%)
7 (22.6%)
3 (9.7%)
NA†
NA†
NA†
NA†
1.000*
17 (51.5%)
16 (48.5%)
6 (18.2%)
27 (81.8%)
19 (57.6%)
8 (24.2%)
16 (51.6%)
15 (48.4%)
5 (16.1%)
26 (83.9%)
17 (54.8%)
9 (34.6%)
NA
NA
NA
NA
NA
NA
1.000
19 (70.4%)
6 (22.2%)
2 (3.8%)
28 (84.0%)
9.6 3.7
17 (65.4%)
8 (30.8%)
1 (3.8%)
16 (53.0%)
7.0 3.7
1.00*
1.000
0.491
NA
NA
−2.6 (−0.8 to 4.5)
0.012
0.006
Continuous variables are summarized by the mean standard deviation.
AL = acute leukemia (AML and ALL); BSA = body surface area; CI = confidence interval; CL = chronic leukemia (CLL and CML); HSCT =
hematopoietic stem cell transplant; NA = treatment difference not applicable; PBSCs = peripheral blood stem cells; PC = platelet concentrate.
* Other = solid tumor, multiple myeloma, and myelodysplasia.
† P values are based on a t test (with unequal variances) and Fisher’s exact test for continuous and categorical variables, respectively.
TABLE 2. Patient exposure to study platelet components
Number of patients
Number of platelet transfusions
Duration of support (days)
Median days of PC support
PC transfused (N)
Median (N) PC transfused
Mean PC platelet dose (× 1011)
PC storage duration (days)
Test
Control
Difference (95% CI)
p value
33
76
8.3 8.7
6.0 (1–35)
2.3 1.4
2.0 (1–5)
3.6 0.4
3.0 0.7
31
89
7.4 6.3
6.0 (1–23)
2.9 1.5
2.0 (1–5)*
3.5 0.4
3.0 0.2
0.9 (−2.8 to 4.7)
NA
−0.6 (−1.3 to 0.2)
NA
0.1 (−0.1 to 0.3)
0.0 (−0.2 to 0.3)
0.618
NA
0.129
NA
0.232
0.860
Data expressed as mean standard deviation.
NA = treatment difference not applicable; PC = platelet concentrate.
* Range (minimum and maximum).
(p = 0.021). One control patient had an SAE unrelated to PC
(Table 4). The most common AEs were chills and pyrexia in
seven control patients, urticaria in five control and two test
patients, HSCT-GVHD in one control patient, and sepsis
unrelated to PC in two test patients. There were no hemorrhagic
AEs reported in either cohort.
Health status at 100-day follow-up
At 100-day follow-up, three test patients (9.1%) and two
control patients (6.5%) were deceased. The causes of death
for test patients were relapsed primary disease (two) and
4 TRANSFUSION
primary graft failure with sepsis (one). For test patients,
death occurred on Study Days 21, 69, and 96. The causes of
death for control patients were sepsis (one) and pneumonia
(one). For the control patients, death occurred on Study
Days 47 and 111. No deaths between the active transfusion
period and the 100-day follow-up were attributed to PC
exposure. Five test patients had primary disease relapse
compared to two control patients.
To examine the possibility that GVHD observed at Day
100 was a delayed form of TA-GVHD, we examined individual
absolute neutrophil counts (ANCs) and platelet counts at Day
REPLACEMENT OF LEUKOREDUCTION
TABLE 3. Mean per-patient 1-hour CI and CCI responses to study platelet transfusions
Pre platelet count (× 109/L)
1-hr platelet count (× 109/L)
1-hr CI (× 109/L)
Median, range 1-hr CI
1-hr CCI (× 103)
Median, range 1-hr CCI
1-HR CCI < 5.0 (× 103)
Test (N = 33)
Control (N = 31)
Difference (95% CI)
p value
15.3 11.4
57.8 24.4
42.5 21.8
36.7 (11.5–113.0)
18.9 8.8
19.4 (6.6–41.6)
6.6%
11.1 6.7
47.7 21.4
36.5 19.2
36.5 (−0.2–78.0)
16.6 8.4
18.4 (−0.1–34.4)
19.1%
4.2 (−0.5 to 8.8)
10.1 (−1.4 to 21.5)
5.9 (−4.3 to 16.2)
6.8 (−3.0 to 16.7)*
2.3 (−2.0 to 6.5)
2.4(−1.9 to 6.6)*
0.080
0.085
0.254
0.173*
0.296
0.272*
0.022†
Data expressed as mean standard deviation.
CCI = corrected count increment; CI = confidence interval.
* Assessed by repeated measures (test-control).
† Fisher’s exact test.
TABLE 4. Treatment-emergent AEs reported per
patient during the active transfusion period*
All grades of AE
Excluded as related
to PC
Related to PC
exposure
Medication required
Recovered from AE
Recovered with
sequelae
Test
(N = 33)
Control
(N = 31)
p value
4 (12.1%)
1
12 (38.7%)
6
0.021
NA
3
6
NA
3
3
1
7
12
0
NA
NA
NA
AE = adverse event; PC = platelet concentrate.
* The relationship of AEs to PC transfusion during the 48-hour
period after PC transfusion was assessed by primary care physicians. All AEs defined as possibly, probably, or certainly
related were classified as related to PC exposure.
Fig. 1. Mean 1-hour CCI responses for test and control cohort
patients during the active transfusion period. Data and number
of patients (n) are presented for all patients, allogeneic HSCT
test and control patients with GVHD(+), for allogeneic HSCT test
and control patients without GVHD(−), and for autologous HSCT
test and control patients. Mean values are represented by the ▲,
median values are represented by the bar, and the interquartile
ranges with outliers are indicated.
100 or last available follow-up (Table S2). Two test patients had
ANC less than 0.5 × 109/L. Patient 121 with Grade 3 GVHD was
in remission with a platelet count greater than 20 × 109/L and
alive at Day 525 after HSCT. Patient 142 had Grade 4 GVHD,
with relapsed acute myeloid leukemia, and died on Study Day
69. The mean ANC (× 109/L) at Day 100 for test and control
patients with GVHD (2.0 1.3) and those without GVHD
(2.1 2.1) were similar (Fig. S1). One test patient (ID 143) with
Grade 2 GVHD and a Day 100 platelet count less than 20 ×
109/L had previously engrafted and was alive without relapse at
Day 211. The mean platelet counts (109/L) at Day 100 for test
and control patients with GVHD (63.8 48.1), and for those
without GVHD (114.7 68.9) indicated reconstitution of
endogenous thrombopoiesis (Table S2 and Fig. S2).
Neutrophil engraftment, ANC of 0.5 × 109/L or greater for
3 days, was attained in 97% of test and 100% of control patients.
Platelet engraftment and platelet count of 20 × 109/L or greater
for 3 days without PC transfusion was attained in 87.9% of test
and 90.3% of control patients. The median times to neutrophil
engraftment and platelet engraftment were similar in the cohorts
(Table S3). The mean ANCs and mean platelet counts of test and
control patients were similar at 100-day follow-up (Figs. S1 and
S2). Furthermore, ANC and platelet count levels were similar
between cohorts for patients with and without HSCT-GVHD
(Figs. S1 and S2). Immune reconstitution at Day 100 by most
proximate serum IgG and IgM levels (Table S4) for test (n = 27)
and control (n = 22) patients with data were within adult reference ranges (IgG, 700–1600 mg/dL; IgM, 40–230 mg/dL).
No patients had a diagnosis of TA-GVHD at the
100-day follow-up. Eleven of 27 (40.7%) test patients had
HSCT-GVHD, compared to 7 of 26 (26.9%) control patients
(p = 0.387). In the test cohort, maximum severity was Grade
2 for seven patients, Grade 3 for three patients, and Grade
TRANSFUSION 5
SIM ET AL.
TABLE 5. Infectious AEs after HSCT through 100-day
follow-up
Clinical status
Infectious AE
Serious infectious AE
Recovered from AE
Recovered with
sequelae
Death from infectious
AE
Test
(33)
Control
(31)
22 (66.7%)
9 (27.3%)
27 (81.8%)
1 (3.0%)
13 (41.9)
6 (20.0%)
9 (77%)
1 (3.3%)
1 (3.0%)
3 (10.0%)
p value
0.078 *
0.564 *
AE = adverse event; HSCT = hematopoietic stem cell transplant.
* Fisher’s exact test
4 for one patient. In the control cohort, the maximum severity was Grade 2 for five patients, Grade 3 for one patient,
and Grade 4 for one patient. In both cohorts the most common organs involved were skin, bowel, and liver.
A substantial proportion of patients had an infectious
AE following HSCT through 100-day follow-up (Table 5),
and more test patients had infectious AEs reported than did
control patients. The primary difference between the
cohorts was due to laboratory detection of CMV antigen
(5 of 33 test vs. 0 of 31 control). However, the AE of active
CMV infection requiring therapy was not different between
cohorts (6 of 33 test vs. 7 of 31 control). The detection of
CMV antigen was most likely due to prior infection based
on high prevalence of CMV in the Hong Kong population.
The incidence of infectious SAE was not different between
cohorts (Test, 27.3%; control, 20.0%). Most patients recovered from infectious SAEs, and only a small proportion in
each cohort died as the result of an infectious AE (Table 5).
DISCUSSION
LR of PC is a common practice for HSCT patients to reduce
the risk of alloimmunization, clinical refractoriness,5,35
transfusion reactions,36 and TTI CMV infection.37 However,
it is not completely effective in mitigating these adverse
transfusion effects. In a study of LR and ultraviolet B light
irradiation, lymphocytotoxic antibodies were reduced, but
17% to 18% of patients exposed to leukoreduced PC developed antibodies, and 7% to 8% of all patients in the LR
cohorts developed refractoriness to PC transfusion.5 A large
retrospective study confirmed that LR decreased the incidence of alloimmunization and clinical refractoriness, but
with substantial residual frequencies for both outcomes in
patients with hematologic malignancy or HSCT.35 Similarly,
prestorage LR of PC has demonstrated efficacy to reduce
the incidence of a wide array of ATRs, but with residual
incidence of 11.4% to 13.3%.36 Although LR results in the
removal of approximately 2 log of cell-associated CMV, it is
not completely effective for prevention of CMV TTI.7,38,39
Importantly, LR alone is not sufficiently effective for prevention of TA-GVHD.40,41
6 TRANSFUSION
A-PR of PC offers the potential to reduce further the
risk of ATR, CMV TTI, and emerging pathogen TTI, and has
been utilized in conjunction with LR for more than 10 years
in Europe.18 This technology inactivates greater than 4 log
of both cell-free and cell-associated CMV with prevention of
CMV TTI in sensitive murine models.23,42 In addition, A-PR
inhibits WBC cytokine synthesis and has demonstrated a
reduction in ATR.25,43 Murine donor splenocytes treated
with low levels (2–20 nm) of amotosalen and ultraviolet A
failed to stimulate responder T cells, did not elicit proliferative responses, and prevented TA-GVHD.26 in vitro T-cell
activation antigen expression was inhibited by amotosalen–
ultraviolet A treatment.44 In a large randomized clinical trial,
recipients of A-PR PC who developed clinical refractoriness
showed a reduction in lymphocytotoxic antibodies.45 Most
importantly, A-PR effectively inactivates greater than 5 log
of T cells27 and has been adopted for prevention of TAGVHD in place of nuclear source irradiation in Europe and
the United States.18,46
To date, all clinical trials and postmarketing studies of
A-PR were conducted with LR. The current study was
intended to assess the efficacy and safety of A-PR PC without LR, gamma irradiation, or bacterial screening to support
routine implementation. In vitro bacterial inactivation data
and extensive postmarketing experience supported the use
of A-PR to replace bacterial screening in Europe and the
United States.14,15,47–49 Robust inactivation of high levels of
T cells and more than 10 years of clinical experience with
A-PR PC with LR in place of gamma irradiation for prevention of TA-GVHD indicated the potential for the use of A-PR
without LR.
In view of extensive prior clinical experience evaluating
the hemostatic efficacy and safety of A-PR PC,18,30,32,45 we
elected to evaluate A-PR PC without LR in a limited HSCT
patient population at risk for TA-GVHD. The test intervention
selected was the buffy coat PC method with platelet additive
solution because the HKRCBTS sought to evaluate pathogen
reduction in place of LR using a process well characterized
in Europe, and prior experience had shown that ultraviolet B
light was effective to reduce alloimmunization.5 The observation of a trend toward reduced allergic transfusion reactions
with test PC was not unexpected, with reduced exposure to
plasma proteins compared to the control suspended in 100%
plasma. We selected the 1-hour CCI to evaluate transfusion
efficacy and ATR to evaluate safety. Both measures have
been used to assess transfusion responses and safety of LR in
prior studies.5 To our knowledge, this is the first study conducted with A-PR without LR, bacterial culture screening, or
gamma irradiation for transfusion of PC.9 The test and control cohorts had similar primary disease and HSCT profiles
with minimal demographic differences, and most received
allogeneic grafts with myeloablative conditioning. Of interest,
the proportion of patients with clinical refractoriness and the
proportion of refractory transfusions were lower in test
cohort patients. The mean 1-hour CI and CCI responses
REPLACEMENT OF LEUKOREDUCTION
were similar between cohorts and consistent with 1-hour CCI
responses observed in other studies of HSCT patients transfused with LR gamma-irradiated PC.2,5 The safety profiles of
test and control PC recipients were not substantially different.
The 100-day follow-up confirmed that the majority of
patients in both cohorts achieved engraftment. Deaths up to
Day 100 were attributed to expected causes: disease relapse,
HSCT graft failure, and bacterial infections not related to PC
exposure. No patients in either cohort had TA-GVHD. The
100-day ANC and platelet count data indicated that the
GVHD observed in both cohorts was related to HSCT and
was not clinically consistent with a diagnosis of TA-GVHD
bone marrow failure.
More patients in the test cohort had HSCT-GVHD, generally of Grade 2 severity. Of interest, all of the test cohort
patients with GVHD had average 1-hour CCI responses
greater than 5.0 × 103 during the active transfusion period,
while two of the control cohort had mean 1-hour CCI
responses less than 5.0 × 103, indicative of clinical refractoriness to platelet transfusion. The incidence of clinical infectious AE through Day 100 follow-up was not substantially
different between the cohorts, and the majority of patients
recovered without sequelae.
The primary limitation of this study was size. However,
conduct of a small study met the objectives of the primary
care physicians (J.S. and A.L.) and the HKRCBTS to evaluate
nonleukoreduced A-PR PC. The study was not designed to
conclusively demonstrate prevention of TA-GVHD, but the
patient population enrolled was at risk for TA-GVHD, and
extensive prior experience with leukoreduced A-PR PC had
shown efficacy for prevention of TA-GVHD in at-risk patient
populations.46 The primary care physicians concluded that
30 patients per cohort primarily treated with ablative HSCT
conditioning would be sufficient to characterize clinical CCI
responses, ATR incidence, and to detect TA-GVHD, if A-PR
failed to be protective. Despite the limited study size, we did
detect multiple 1-hour CCI responses less than 5.0 × 103 and
patients with clinical refractoriness. HLA antibody status was
not measured during the study, and thus we could not determine the incidence of immune-mediated refractoriness.
Hence, the study size does not allow a definitive conclusion
that A-PR PC without LR are superior to conventional PC
without LR for either transfusion efficacy or alloimmune
refractoriness. Prior large studies comparing CCI responses
of A-PR PC with untreated PC have shown lower CCI
responses; thus, we cannot conclusively generalize the observations from this study to indicate no difference in CCI
responses with A-PR PC.45 Nonetheless, within the scope of
this study, we did not detect any differences in efficacy or
unexpected safety signals in the health status of HSCT recipients supported with nonleukoreduced A-PR PC. Surveillance
of a larger population supported with A-PR PC without LR
during routine use will be useful to extend the safety profile
of nonleukoreduced A-PR PC. Within the limitations of this
study, replacement of LR, bacterial culture screening, CMV
serology, and gamma irradiation with A-PR whole blood–
derived PC appears feasible and offers the potential benefit
to reduce the cost of PC transfusion, simplify PC production
and inventory, and reduce the risk of TTI from a broad spectrum of known and emerging pathogens.
ACKNOWLEDGMENTS
The authors acknowledge the assistance of Pascal Maillard and
Rebecca Yeung for facilitating the study. J-S Lin, PhD, contributed
to the statistical discussions. Dr. Lily Lin, former vice president for
scientific affairs, Cerus, and Dr. Che Kit Lin, former director of the
HKRCBTS, provided initial guidance and inspiration for the conduct
of this study.
CONFLICT OF INTEREST
JS, WCT, CKL, RL, CCKL, and AKWL have disclosed no conflicts of
interest. Cerus Corporation, manufacturer of the INTERCEPT Blood
Systems for Platelets, provided institutional research support for
performance of the study. CK, AYL, NH, RJB, HJV, AS, and LC are
employees of Cerus Corporation and beneficial owners of Cerus
equities or options during the conduct of this study, analysis of the
data, and preparation of the manuscript. JS, WCT, CKL, RL, CCKL,
and AKWL conducted the clinical study. JS, WCT, and AKWL determined the scope and design of the study. CK and AYL monitored
study data. NH designed the data collection methods and performed the biostatistics analysis. HJV transferred the A-PR technology and the production of whole blood–derived buffy coat PC to
the HKRCBTS. AS cowrote the clinical protocol, monitored PC production, and coordinated interactions with the sponsor. RJB
reviewed study data and edited the manuscript. LC wrote the clinical trial protocol, reviewed clinical data, and wrote the manuscript.
REFERENCES
1. Rebulla P, Finazzi G, Marangoni F, et al. The threshold for
prophylactic platelet transfusions in adults with acute myelogenous leukemia. N Engl J Med 1997;337:1870-5.
2. Slichter SJ, Kaufman RM, Assman SF, et al. Dose of prophylactic platelet transfusions and prevention of hemorrhage. N Engl
J Med 2010;362:600-13.
3. Stanworth SJ, Estcourt LJ, Powter G, et al. A no-prophylaxis
platelet-transfusion strategy for hematologic cancers. N Engl J
Med 2013;368:1771-80.
4. Bowden RA, Slichter SJ, Sayers MH, et al. Use of leukocytedepleted patelets and cytomegalovirus seronegative red cells
for prevention of primary cytomegalovirus infection after
marrow transplant. Blood 1991;79:246-50.
5. TRAP Study Group. Leukocyte reduction and ultraviolet B irradiation of platelets to prevent alloimmunization and refractoriness to platelet transfusions. N Engl J Med 1997;337:1861-9.
6. Snyder E. Transfusion reactions. In: Hoffman R , Benz E ,
Shattil S et al., editors. Hematology: Basic Principles and Practice. Philadelphia: Churchill Livingstone; 2000. p. 2300-10.
TRANSFUSION 7
SIM ET AL.
7. Wu Y, Zou S, Cable R, et al. Direct assessment of cytomegalovirus transfusion-transmitted risks after universal
leukoreduction. Transfusion 2010;50:776-86.
8. Ziemann M, Krueger S, Maier AB, et al. High prevalence of
cytomegalovirus DNA in plasma samples of blood donors in
connection with seroconversion. Transfusion 2007;47:1972-83.
9. Kopolovic I, Ostro J, Tsubota H, et al. A systematic review of
transfusion-associated graft-versus-host disease. Blood 2015;
126:406-14.
10. Hong H, Xiao W, Lazarus HM, et al. Detection of septic transfusion reactions to platelet transfusions by active and passive
surveillance. Blood 2016;127:496-502.
11. Stramer SL, Dodd RY. AAABB transfusion-transmitted diseases
emerging infectious diseases subgroup. transfusion-transmitted
emerging infectious diseases: 30 years of challenges and progress. Transfusion 2013;53(10 Pt 2):2375-83.
12. Stramer SL, Linnen JM, Carrick JM, et al. Dengue viremia in
collection establishments and transfusion services to enhance
the safety and availability of platelets for transfusion: draft guidance for industry. In: Center for Biologics Evaluation and
Research, editors. Silver Spring (MD): US Department of Health
and Human Services Food and Drug Administration; 2016.
23. Jordan CT, Saakadze N, Newman JL, et al. Photochemical treatment of platelet concentrates with amotosalen hydrochloride
and ultraviolet A light inactivates free and latent cytomegalovirus
in a murine transfusion model. Transfusion 2004;44:1159-65.
24. Fiebig E, Hirschkorn D, Busch M, et al. Loss of inducible CD69
expression on donor T cells (CD3CD69) in platelet
concentrates(PCs) by storage, irradiation, and photochemical
treatment. Transfusion 1997;37:92s.
25. Hei DJ, Grass J, Lin L, et al. Elimination of cytokine production in
stored platelet concentrate aliquots by photochemical treatment
with psoralen plus ultraviolet A light. Transfusion 1999;39:239-48.
26. Roback JD, Hossain MS, Lezhava L. Allogeneic T cells treated
blood donors identified by RNA and detection of dengue trans-
with amotosalen prevent lethal cytomegalovirus disease with-
fusion transmission during the 2007 dengue outbreak in Puerto
Rico. Transfusion 2012;52:1657-66.
out producing graft-versus-host-disease following bone marrow transplantation. J Immunol 2003;171:6023-31.
13. Kuehnert MJ, Epstein JS. Assuring blood safety and availability:
27. Castro G, Merkel PA, Giclas HE, et al. Amotosalen/UVA treat-
Zika virus, the latest emerging infectious disease battlefront.
Transfusion 2016;56:1669-72.
14. Osselaer JC, Doyen C, Defoin L, et al. Universal adoption of
pathogen inactivation of platelet components: impact on platelet and red blood cell component use. Transfusion 2009;49:
1412-22.
ment inactivates T cells more effectively than the recommended
gamma dose for prevention of transfusion-associated graftversus-host disease. Transfusion 2018;58:1506-15.
28. Sharma RR, Marwaha N. Leukoreduced blood components:
advantages and strategies for its implementation in developing
countries. Asian J Transfus Sci 2010;4:3-8.
15. Cazenave JP, Isola H, Waller C, et al. Use of additive solutions and
pathogen inactivation treatment of platelet components in a
29. Liu HW, Yuen KY, Cheng TS, et al. Reduction of platelet
transfusion- associated sepsis by short-term bacterial culture.
regional blood center: impact on patient outcomes and component utilization during a 3-year period. Transfusion 2011;51:622-9.
Vox Sang 1999;77:1-5.
30. van Rhenen DJ, Gulliksson H, Cazenave JP, et al. Transfusion
16. Nussbaumer W, Amato M, Schennach H, et al. Patient outcomes and amotosalen/UVA-treated platelet utilization in massively transfused patients. Vox Sang 2017;112:249-56.
17. Knutson F, Osselaer J, Pierelli L, et al. A prospective, active
hemovigilance study with combined cohort analysis of 19,175
transfusions of platelet components prepared with amotosalenUVA photochemical treatment. Vox Sang 2015;109:342-52.
18. Corash L, Benjamin RJ. The role of hemovigilance and postmarketing studies when introducing innovation into transfusion medicine practice: the amotosalen-ultraviolet A pathogen
reduction treatment model. Transfusion 2016;56(Suppl 1):
S29-38.
of pooled buffy coat platelet components prepared with photochemical pathogen inactivation treatment: the euroSPRITE
trial. Blood 2003;101:2426-33.
31. Snyder E, McCullough J, Slichter SJ, et al. Clinical safety of
platelets photochemically treated with amotosalen HCl and
ultraviolet A light for pathogen inactivation: the SPRINT trial.
Transfusion 2005;45:1864-75.
32. Lozano M, Knutson F, Tardivel R, et al. A multi-centre study of
therapeutic efficacy and safety of platelet components treated
with amotosalen and ultraviolet A pathogen inactivation stored
for 6 or 7 d prior to transfusion. Br J Haematol 2011;153:393-401.
33. Ishida A, Handa M, Wakui M, et al. Clinical factors influencing
19. Cerus Corporation. INTERCEPT Blood System for Platelets.
posttransfusion platelet increment in patients undergoing
2014. Concord, CA: Cerus Corporation; 2015.
20. Food and Drug Administration Center for Biologics Evaluation
hematopoietic progenitor cell transplantation-a prospective
analysis. Transfusion 1998;38:839-47.
and Research. Revised recommendations for reducing the risk
34. Hod E, Schwartz J. Platelet transfusion refractoriness. Br J
of Zika virus transmission by blood and blood components. In:
Department of Health and Human Services, editors.
Haematol 2008;142:348-60.
35. Seftel MD, Growe GH, Petraszko T, et al. Universal prestorage
Washington (DC): US FDA; 2016.
21. Musso D, Richard V, Broult J, et al. Inactivation of dengue virus
in plasma with amotosalen and ultraviolet A illumination.
Transfusion 2014;54:2924-30.
22. US Department of Health and Human Services Food and Drug
Administration. Bacterial risk control strategies for blood
8 TRANSFUSION
leukoreduction in Canada decreases platelet alloimmunization
and refractoriness. Blood 2004;103:333-9.
36. Heddle NM, Blajchman MA, Meyer RM, et al. A randomized
controlled trial comparing the frequency of acute reactions to
plasma-removed platelets and pre-storage WBC-reduced platelets. Transfusion 2002;42:556-66.
REPLACEMENT OF LEUKOREDUCTION
37. Bowden RA, Slichter SJ, Sayers M, et al. A comparison of filtered
leukocyte-reduced and cytomegalovirus (CMV) seronegative
blood products for the prevention of transfusion-associated
CMV infection after marrow transplant. Blood 1995;86:3598-603.
38. Nichols WG, Price TH, Gooley T, et al. Transfusion-transmitted
cytomegalovirus infection after receipt of leukoreduced blood
products. Blood 2003;101:4195-200.
39. Mainou M, Alahdab F, Tobian AA, et al. Reducing the risk of
transfusion-transmitted cytomegalovirus infection: a systematic
review and meta-analysis. Transfusion 2016;56Pt 2:1569-80.
40. Pelszynski MM, Moroff G, Luban NLC, et al. Effect of gamma
irradiation on T-cell inactivation as assessed by limiting dilu-
47. Amato M, Schennach H, Astl M, et al. Impact of platelet pathogen inactivation on blood component utilization and patient
safety in a large Austrian Regional Medical Centre. Vox Sang
2016;112:47-55.
48. Schmidt M, Hourfar MK, Sireis W, et al. Evaluation of the effectiveness of a pathogen inactivation technology against clinically
relevant transfusion-transmitted bacterial strains. Transfusion
2015;55:2104-12.
49. Wagner SJ, Benjamin RJ, Hapip CA, et al. Investigation of bacterial inactivation in apheresis platelets with 24 or 30 hours
between inoculation and inactivation. Vox Sang 2016;111:
226-34.
tion analysis: implications for preventing transfusion associated
graft vs. host disease. Blood 1994;83:1683-9.
41. Stroncek DF, Rebulla P. Platelet transfusions. Lancet 2007;370:
427-38.
42. Lin L. Inactivation of cytomegalovirus in platelet concentrates using
Helinx™ technology. Semin Hematol 2001;38(4 Suppl 11):27-33.
43. Amsler L, Jutzi M. Haemovigilance Annual Report 2015. Bern,
Switzerland: Swissmedic; 2016.
44. Fiebig E, Hirschkorn DF, Maino VC, et al. Assessment of donor
T-cell function in cellular blood components by the CD69
induction assay: effects of storage, gamma irradiation, and
photochemical treatment. Transfusion 2000;40:761-70.
45. McCullough J, Vesole DH, Benjamin RJ, et al. Therapeutic efficacy
and safety of platelets treated with a photochemical process for
pathogen inactivation: the SPRINT Trial. Blood 2004;104:1534-41.
46. Corash L, Lin L. Novel processes for inactivation of leukocytes
to prevent transfusion-associated graft-versus-host disease.
Bone Marrow Transplant 2004;33:1-7.
SUPPORTING INFORMATION
Additional Supporting Information may be found in the
online version of this article.
TABLE S1. Conditioning regimen for HSCT patients in control and test cohorts
TABLE S2. 1- HR CCI responses during the active transfusion period, Day 100 ANC, and Day 100 platelet counts for
patients with HSCT-related GVHD
TABLE S3. Time to neutrophil and platelet engraftment and
100-day ANC and platelet count
TABLE S4. Serum IgG and IgM levels at 100-day follow-up
Fig. S1. Absolute neutrophil counts for test and control
cohort patients at Day 100 follow-up
Fig. S2. Platelet counts for test and control cohort patients
at Day 100 follow-up.
TRANSFUSION 9