AM21-75 Strategies to address critical

stresses on the platelet inventory

Novel platelet storage strategies to

improve supply and minimise

wastage

Denese C Marks

Australian Red Cross Lifeblood

dmarks@redcrossblood.org.au

Faculty Disclosure

Research funding from:

• Macopharma

• Cryogenics Holdings Pty Ltd

Member of Scientific Advisory Board for Vitrafy Life Sciences

In compliance with ACCME policy,

AABB requires the following

disclosures to the session audience

Objectives

• Describe characteristics of cold stored and cryopreserved platelets

• Advantages of these storage modes

• Ways they can be implemented to manage platelet inventory

• Gaps in knowledge and important considerations

• Clinical evidence for use

• Regulatory status

Cold stored platelets

Taken from Scorer et al., Transfusion 2019

Cold-stored platelets are a hot topic

Cold-stored platelets are a hot topic

Storage at room temperature (20-24 °C) with agitation

• Maximises platelet recovery and survival in transfusion recipients1

Disadvantages of RT storage

• Short shelf-life (5-7 days)

Platelet storage lesion

Bacterial proliferation

• Inventory management challenges – remote and rural hospitals

Conventional storage of platelets

1. Murphy & Gardner. N Engl J Med 1969;280:1094-8

Cold-stored platelets

Simplicity - storage in refrigerator (2-6 °C) without

agitation

Cold-stored platelets are not new!!

• Historical platelet storage method

• Reduced platelet survival in transfused recipients1

• RT-storage adopted to maximise outcomes of prophylactic

transfusions

1. Murphy & Gardner. N Engl J Med 1969

From Murphy and Gardner, 19691

Reduced metabolism ► longer shelf-life

Apheresis platelets in 100% plasma Apheresis platelets in 40% plasma/60% SSP+

Advantages: cold storage slows metabolism

1 2 5 9 14 21

0

2

4

6

8

Storage time (days)

Glu

co

se (

mm

ol/L

)

RT

Cold-stored

1 2 5 7 9 14 21

0

5

10

15

20

25

Storage time (days)

Glu

co

se (

mm

ol/L

)

RT

Cold-stored

Adapted from Johnson et al., Transfusion 2021

Cold-storage reduces bacterial proliferation

Taken from Ketter et al., Transfusion 2019

Procoagulant platelets

• Surface for assembly of coagulation factors

• Generation of thrombin burst

• Fibrin formation and clot stability

• Link between unstable aggregate and stable clot

Cold-stored platelets are more procoagulant

1 2 5 7 10 14 21

0

10

20

30

40

50

Storage time (days)

An

nex

in-V

(%

po

sit

ive)

*

1 2 5 7 10 14 21

0

5000

10000

15000

Storage time (days)

Mic

rop

art

icle

s (

x10

6/u

nit

)

*

Increased procoagulant capacity ► better able to stem bleeding?

Cold-stored platelets have better clotting function

Nair et al., BJH 2017

FDA approval

• 21 CFR 606.65(e) & 610.53(c) To store apheresis platelet products at 1-6 °C for up

to 14 days without agitation. The cold stored platelet products will be used to treat

actively bleeding patients when conventional platelet products are not available, or

their use is not practical 1

• South Texas Blood and Tissue Centre received FDA approval April 2020 – platelets must

be refrigerated within 2 hours of collection2

• Mayo clinic received approval for use of cold-stored platelets during COVID-19 pandemic

(April 2020)2

Regulatory status- are they available now?

1. US FDA Exceptions and Alternative Procedures Approved Under 21 CFR 640.120; 2. Warner et al., Transfusion 2020

Implementation?

Johnson et al., Transfusion 2021; Wagner et al., Transfusion 2020

Transfer day 1 post-collection

Transfer 8 hours post-collection

South Texas Blood and Tissue Centre – Transfer 2 hours post collection

Delayed cold-storage: minimising wastage

Wood et al, Vox Sanguinis 2018; Braathen et al, Transfusion 2019; Warner et al, Transfusion 2020

Transfer on day 4 post-collection

Transfer on day 7 post-collection

Transfer on day 5 post-collection

- 40 patients transfused

- haemostasis/no adverse effects

Plasma or PAS?

Reddoch-Cardenas et al, Transfusion 2021; Getz et al., Transfusion 2016

Knowledge gaps: bacterial proliferation

Reduced bacterial proliferation… but not eliminated

Should cold-stored platelets still be screened for bacterial contamination?

Ramirez-Arcos et al., Vox Sanguinis 2021 (ISBT abstract)

• Do cold-stored platelets still need to be screened for bacterial contamination? If they are transferred from RT storage at or near expiry, then yes!

• Alternatively, can cold-stored platelets be PI treated?

Knowledge gaps – pathogen inactivation

1 2 5 7 9

500

600

700

800

900

1000

Storage time (days)

Pla

tele

t co

un

t (x

10

9/L

) RT untreated

RT UVC-PI

Cold untreated

Cold UVC-PI

Johnson et al., Transfusion 2018

Knowledge gaps: the optimum shelf-life?

Taken from Stolla et al., Transfusion 2019

Maximum shelf-life?

Platelet count vs. haemostatic activity

Clinical trials still needed

Clinical evidence

1. Becker et al., Transfusion 1973; 2. Strandenes et al., Anesthesiology 2020; 3. Warner et al., Transfusion 2020; 4. Krachey et al., J Trauma Acute

Care Surg. 2018; 5. clinicaltrials.gov (NCT04834414)

• Cold-stored platelets superior to RT platelets for treatment of bleeding thrombocytopaenic

patients1

• Norway - Pilot trial in bleeding cardiac surgery patients

Cold stored platelets prevented bleeding following 7 and 14 days of cold-storage

No adverse events 2

• Cold-stored platelets (delayed transfer to cold) used at Mayo Clinic during COVID-19

safe and provided effective haemostatis3

• The CHIPS RCT will recruit 1000 adult and paediatric cardiac surgery patients receiving

conventional or cold-stored platelets4,5

Advantages

• Extended shelf-life, possibly to 21 days

• Reduced bacterial proliferation

• Increased haemostatic potential

Implementation options for blood banks

• Immediate cold-storage

• Delayed cold-storage

Considerations

• Bacterial contamination screening or PI?

• Plasma or PAS

In summary…

Cryopreserved platelets

Cryopreserved platelets: an unmet clinical need

5-6% DMSO

-80 °C storage

2-4 year shelf-life1

1. Lelkens et al., 2006

Frozen platelets are not new either

• US Navy 1970s technology – Dr Robert Valeri1,2

• Later adopted and used extensively by Dutch military3,4

• Now also used in civilian or military settings in Australia,

Czech Republic, France, Singapore, Switzerland and

others6,7

1. Valeri et al., Blood 1974; 2. Valeri et al., Tranfusion 2005; 3.; 4. Lelkens et al., 2006; 5. Noorman et al., Plos ONE 2016; 6. Bondar et al., Transfusion

2014 (AABB abstract); 7. Cohn et al., Vox Sanguinis 2017

1 2 5 7 9 14 21 0 240

20

40

60

80

An

ne

xin

-V (

%)

Post-thaw(hours)

Liquid storage(days)

1 2 5 7 9 14 21 0 240

40000

80000

500000

Mic

rop

art

icle

s (

x10

6/L

)

Post-thaw(hours)

Liquid storage(days)

RTCold

Frozen

Increased haemostatic potential

Multiple changes due to freeze-thaw damage

Adapted from Wood et al., Transfusion 2016; Johnson et al, Transfusion 2018; Tohidi-Esfahani et al., Vox Sanguinis 2017 (ISBT abstract)

Clinical evidence

Cryopreservation reduces in vivo recovery and survival

Dumont et al., Transfusion 2013

University of Maryland: program established to address shortages of HLA-matched platelets1

• > 1600 autologous cryopreserved platelet units to support chemotherapy patients

• Platelet increments achieved

• An effective way to create an inventory of frozen platelets

After introduction of a massive transfusion protocol, more patients received frozen platelets

and fewer died2

Clinical evidence – in practice

1. Schiffer et al., Prog Clin Biol Res; 2. Noorman et al., Plos ONE 2016

1043 units transfused in Afghanistan with no adverse effect

Dutch military – platelets prepared in advance to meet future transfusion needs

Randomised clinical trials

Shlicter et al., Transfusion 2018

Cryopreserved platelets effective for bleeding thrombocytopaenic patients

Randomised clinical trials

Reade et al., Transfusion 2018

• Pilot RCT, 41 patients

• CLIP: Cryopreserved vs. conventional platelets in bleeding cardiac surgery patients

• Typically frozen within 48-50 hours of collection, with bacterial screening1,2

• Can also be frozen at expiry with no loss in platelet quality post-thaw3,

minimise wastage

• Post-thaw shelf-life 4-6 hours1,2 but combined with cold storage (post-thaw) it could be

longer4

How can they be used – minimising wastage?

1. Noorman et al., Plos ONE 2016; 2. Reade et al., Transfusion 2018; 3. Johnson et al., Transfusion March 2020; 4. Johnson et al., Transfusion Jul 2020

In summary

• Cryopreservation can extend platelet shelf-life to at least 2 years

• RCT and retrospective data show safety, efficacy and practicality

• Further trials under way

• Not approved in US; approved and used in other countries

32

Acknowledgements Lacey Johnson April Davis Shereen Tan

Ben Wood Lauren Waters Sarah Raynel

Thank you

Denese C Marks

Australian Red Cross Lifeblood

dmarks@redcrossblood.org.au