FAQ: Information for health professionals on pathogen-reduced platelets

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NOTE: This information reflects evidence available at time of publication. This information is specific to Pooled Platelet Psoralen-Treated (PPPT) components, which are being implemented nationally one distribution site at a time.

 

General

1. How do component characteristics for pathogen-reduced platelets (specifically pooled platelet psoralen-treated or PPPT) compare to untreated platelets?

See Table 1 for a comparison of component characteristics (this table is excerpted from Chapter 19 of the Clinical Guide to Transfusion).

Table 1: Component characteristics of PPPT and untreated platelets

Component characteristic Untreated pooled platelet Untreated apheresis platelet Pooled platelet psoralen-treated (PPPT
Mean unit volume (mL) 317 223 184
Number of donors in component 4 1 7
Mean plasma volume (mL) 317 (approximately 20 mL for 3 donors and + 257 mL plasma from one male donor) 173 75 (approximately 11 mL per donor)
Approximate platelet count
(x109 platelets per L)
1,069 1,493 1,363
Approximate platelet yield
(x109 platelets per unit)
339 333 251
Resuspension solution Plasma Plasma Approx. 60% Platelet Additive Solution (PAS-E)
40% Plasma
Anticoagulant CPD ACD-A CPD
Bacterial screening performed by Canadian Blood Services Yes Yes No
Typical time to release component to hospital after blood collection from donor Day 3 Day 3 Day 2
Component shelf life (from day of blood collection) 7 days 7 days 5 days
Viable lymphocytes present?  Yes, irradiation required for vulnerable patients Yes, irradiation required for vulnerable patients Viable lymphocytes not present, irradiation not required for vulnerable patients

2. What is the technology used for pathogen-reduced platelet components, and how does it work?

Canadian Blood Services uses the INTERCEPT Pathogen Inactivation Technology by Cerus to treat platelets. This technology uses a psoralen compound (amotosalen) and UV light to cause irreversible damage to genetic material present in pathogens, rendering them inactive.

3. Will pooled platelets psoralen-treated (PPPT) completely replace untreated pooled platelets?

Once PPPT are implemented at a Canadian Blood Services site, the current untreated pooled platelet component will no longer be produced by that site.

4. Could PPPT be released to my hospital before my production site implements them?

Yes, this is possible. Canadian Blood Services manages a national platelet inventory so hospitals could receive PPPT even though their local Canadian Blood Services site has not yet implemented the manufacturing of this component.

5. Could untreated pooled platelets be released to my hospital after my production site implements PPPT?

Yes, this is possible. Canadian Blood Services manages a national platelet inventory. It is possible that hospitals may receive untreated components to meet inventory demands as PPPT production rolls out across the country.

6. Will PPPT replace untreated apheresis platelets? Will there be a change in available inventory of untreated apheresis platelets?

Untreated apheresis platelets will remain available. However, untreated apheresis platelets, which are currently suspended in plasma, will be suspended in platelet additive solution pending Health Canada submission and review. Canadian Blood Services also plans to pathogen reduce most of our apheresis platelets in the future (pending Health Canada submission and review); these will be called Apheresis Platelet Psoralen-Treated (APPT).

7. Can we order both units of PPPT originating from the same parent unit?

Yes, a paired dose can be issued to a hospital, if specifically requested and if available. Standard platelet orders will be issued by the oldest expiry, unless otherwise indicated.

8. Why is the shelf life of PPPT limited to 5 days?

Currently, the INTERCEPT Pathogen Inactivation Technology licensed in Canada is for a shelf life of 5 days. Cerus is actively working on obtaining a 7-day shelf life approval with Health Canada.

9. What post-implementation data collection and analysis is taking place?

Canadian Blood Services will be monitoring for changes in platelet component demand, wastage, and inventory changes.

10. What information is Health Canada monitoring regarding the use of pathogen-reduced platelets?

Health Canada is expected to evaluate the residual leukocyte content, pH, and platelet yield, as well as sterility testing at time of expiration.

11. Do hospitals need to perform isoagglutinin titrations with the PPPT since they are suspended in a combination of PAS and plasma?

While the ABO antibody concentration will decrease due to the removal of approximately 60% of the plasma and addition of Platelet Additive Solution (PAS), Canadian Blood Services cannot make any claims about ABO titres of the final PPPT components. Hospitals can make a segment from the sampling pouch line and use it to prepare a titration if desired.

Components and administration

12. Will hospitals need to continue irradiating untreated (pooled or apheresis) platelets provided by Canadian Blood Services?

Untreated (pooled or apheresis) platelet components need to be irradiated as per standard practices when clinically indicated. Canadian Blood Services will continue to provide irradiated untreated platelet components to hospitals.  Pathogen reduced platelet components should not undergo irradiation and are safe to use for recipients requiring irradiated blood components.

13. What will happen to HLA and HPA matched platelets?

Both HLA and HPA matched platelets will continue to be manufactured without pathogen reduction at this time. In the future, Canadian Blood Services plans to pathogen reduce most of our apheresis platelet inventory (including HLA and HPA matched platelets). Non pathogen-reduced platelets will remain available for select populations, including patients with psoralen allergies. Once pathogen reduced apheresis platelet components are implemented, orders for untreated HPA matched platelets will require advanced notice.

14. Can a PPPT unit be volume-reduced?

No, PPPT unit should not be volume-reduced (centrifuged and supernatant removed) prior to transfusion. Volume reduction may cause aggregation of platelets due to an increased surface area to volume ratio.

15. Can aliquots be obtained from a PPPT unit for transfusion? What is the minimal residual volume of a PPPT unit?

Yes, aliquots can be obtained as long as a minimal residual volume of 135mL remains in the platelet bag. In other words, once there is 135mL or less remaining in the platelet bag, the platelet component can no longer be used and no further aliquots can be obtained.

16. Do untreated (apheresis or pooled) platelet components have the same concentration as PPPT?

No, untreated platelet components are less concentrated than PPPT. The final concentration of the PPPT component is approximately 1.4 times more concentrated than untreated pooled platelets. Please see Table 1.

17. Is the tail on the PPPT unit long enough to allow docking to another bag?

Yes, once the bulb is removed, the remaining tubing length is approximately 8 cm. This should be sufficient for docking another bag depending on the tube welder device used.

18. Can a patient receive both untreated (apheresis or pooled) platelets and PPPT to meet their transfusion requirements?

Yes, patients may receive both untreated platelets and PPPT to meet their transfusion requirements.

19. Can the same line be used for untreated (apheresis or pooled) platelets and PPPT?

Yes, both PPPT and untreated (apheresis or pooled) platelets can be hung in the same line, provided the tubing has not expired.

20. Is there a difference in infusion time with the various platelet components?

No, PPPT can be transfused at the same rate as untreated (apheresis or pooled) platelets. The rate should follow hospital policy.

Clinical use

21. Is premedication required before receiving a PPPT unit?

Premedication is not specifically required for transfusion of PPPT components.

22. What is the adult dose of a PPPT component compared with other platelet components?

For adults, a PPPT component will be equivalent to an untreated (pooled or apheresis) platelet component.

23. What is the neonatal and pediatric dosing for PPPT and untreated platelets?

For both PPPT and untreated platelet components the recommended doses for pediatric and neonatal platelet transfusions are provided in the Canadian Blood Services Circular of Information.

24. Can PPPT be administered to patients undergoing extracorporeal photopheresis (ECP) or PUVA light therapy?

PPPT are not indicated for neonatal patients treated with phototherapy devices that emit a peak energy wavelength less than 425 nm or have a lower bound of the emission bandwidth <375 nm, due to the potential for erythema resulting from interaction between ultraviolet light and amotosalen. Phototherapy in the blue-green light with peak wavelength of 450-460nm is the current standard of care for treatment of neonatal hyperbilirubinemia in Canada.1

25. Is the corrected count increment (CCI) expected to be similar following a dose of PPPT?

The current evidence suggests that CCIs are lower for PPPT components compared with untreated platelets. Only 7% of hematology oncology patients transfused with pathogen-reduced platelets required additional platelet transfusions compared to patients transfused with untreated platelets.2

26. Will the increased number of donors in PPPT increase HLA alloimmunization?

No, the current evidence does not suggest an increased risk of HLA alloimmunization. There are conflicting data regarding alloimmunization rates due to the varying preparations of pathogen-reduced platelets and technologies deployed in clinical trials. Overall, there appears to be no change in alloimmunization rate with INTERCEPT platelets.3

References

  1. Barrington KJ, S.K., Canadian Paediatric Society, Fetus and Newborn Committee. Guidelines for detection, management and prevention of hyperbilirubinemia in term and late preterm newborn infants (35 or more weeks' gestation) - Summary. Paediatr Child Health 12, 401-418 (2007).
  2. Estcourt, L.J., Malouf, R., Hopewell, S., et al. Pathogenreduced platelets for the prevention of bleeding. Cochrane Database of Systematic Reviews 7;7, (2017).
  3. McCullough, J., Vesole, D.H., Benjamin, R.J., et al. Therapeutic efficacy and safety of platelets treated with a photochemical process for pathogen inactivation: the SPRINT Trial. Blood 104, 1534-1541 (2004).