Implications of the US Food and Drug Administration draft guidance for mitigating septic reactions from platelet transfusions

A national survey of hospital-based transfusion services on their approaches to platelet bacterial risk mitigation in response to the FDA final guidance for industry

BACKGROUND

Bacterial contamination of platelets is the leading infectious risk to the United States (US) blood supply. On 30 September 2019, the US Food and Drug Administration (FDA) published a Final Guidance for Industry to reduce the risk of transfusing platelets contaminated by bacteria. A national survey was undertaken to assess readiness, attitudes, and the potential impact on hospital-based transfusion services.

STUDY DESIGN AND METHODS

A survey was distributed to transfusion services in all 50 US states. Summary statistics were performed along with review and categorization of email feedback and free text comments.

RESULTS

Eighty-three transfusion services from 48 states participated in this survey study. Currently, the most common approach is primary culture performed at manufacturing (n = 49/83, 59%). Of the bacterial risk mitigation strategies provided by the FDA, the most frequently preferred are (a) pathogen reduced platelets (PRP) for up to 5-day storage (n = 36/77, 47%), (b) large volume delayed sampling (LVDS) ≥48 hours for up to 7-day storage (n = 16/77, 21%), and (c) primary culture ≥24 hours + secondary rapid testing for up to 7-day storage (n = 7/77, 9%). The main motivating factors for the survey participants' selected strategies to comply with FDA final guidance were product availability from supplier, reducing the risk of septic transfusion reactions (STR), and complexity of implementing and performing a new or additional test.

CONCLUSION

While having platelets to transfuse and preventing STR are of the utmost importance, nationwide, the majority of transfusion services do not want to take on performing new or additional testing in their laboratories.

How do you… decide which platelet bacterial risk mitigation strategy to select for your hospital-based transfusion service?

The United States Food and Drug Administration Final Guidance for Industry titled, "Bacterial Risk Control Strategies for Blood Collection Establishments and Transfusion Services to Enhance the Safety and Availability of Platelets for Transfusion" provides nine strategies for platelet bacterial risk mitigation. Even if it is assumed all strategies are comparable in terms of safety and efficacy, the decision of which to implement remains challenging. Some additional factors that warrant evaluation before selecting a strategy include the financial impact, process for implementation, logistics upon implementation, institutional acceptance by blood bank staff, administration and clinicians, and effect on platelet availability. To assist with this difficult choice, a panel of transfusion service physicians who have expertise on the topic and have already selected strategies for their transfusion services were recruited to provide varied perspectives. In addition, the use of a decision-making tool that objectively evaluates defined criteria for assessment of the nine strategies is described.

The long and winding road to pathogen reduction of platelets, red blood cells and whole blood

Pathogen reduction technologies (PRTs) have been developed to further reduce the current very low risks of acquiring transfusion-transmitted infections and promptly respond to emerging infectious threats. An entire portfolio of PRTs suitable for all blood components is not available, but the field is steadily progressing. While PRTs for plasma have been used for many years, PRTs for platelets, red blood cells (RBC) and whole blood (WB) were developed more slowly, due to difficulties in preserving cell functions during storage. Two commercial platelet PRTs use ultra violet (UV) A and UVB light in the presence of amotosalen or riboflavin to inactivate pathogens' nucleic acids, while a third experimental PRT uses UVC light only. Two PRTs for WB and RBC have been tested in experimental clinical trials with storage limited to 21 or 35 days, due to unacceptably high RBC storage lesion beyond these time limits. This review summarizes pre-clinical investigations and selected outcomes from clinical trials using the above PRTs. Further studies are warranted to decrease cell storage lesions after PRT treatment and to test PRTs in different medical and surgical conditions. Affordability remains a major administrative obstacle to PRT use, particularly so in geographical regions with higher risks of transfusion-transmissible infections.

Recipient sepsis caused by Lactococcus garvieae contamination of platelets from a donor with colon cancer

Lactococcus garvieae is a well-known fish pathogen that has low virulence in humans and is rarely isolated from the blood cultures of endocarditis patients. We describe herein the first reported case of transfusion-transmitted L. garvieae sepsis caused by a contaminated platelet concentrate from a donor who consumed raw octopus before blood donation. Retrospective examination of the laboratory results of the index donor revealed that his haemoglobin levels had been steadily decreasing, which led to the detection of a latent colon cancer. The donors with colon lesions involving a latent cancer may relate an asymptomatic bacteremia.

Refrigeration, cryopreservation and pathogen inactivation: an updated perspective on platelet storage conditions

Conventional storage of platelet concentrates limits their shelf life to between 5 and 7 days due to the risk of bacterial proliferation and the development of the platelet storage lesion. Cold storage and cryopreservation of platelets may facilitate extension of the shelf life to weeks and years, and may also provide the benefit of being more haemostatically effective than conventionally stored platelets. Further, treatment of platelet concentrates with pathogen inactivation systems reduces bacterial contamination and provides a safeguard against the risk of emerging and re-emerging pathogens. While each of these alternative storage techniques is gaining traction individually, little work has been done to examine the effect of combining treatments in an effort to further improve product safety and minimize wastage. This review aims to discuss the benefits of alternative storage techniques and how they may be combined to alleviate the problems associated with conventional platelet storage.

Pathogen Inactivation of Cellular Blood Products-An Additional Safety Layer in Transfusion Medicine

In line with current microbial risk reduction efforts, pathogen inactivation (PI) technologies for blood components promise to reduce the residual risk of known and emerging infectious agents. The implementation of PI of labile blood components is slowly but steadily increasing. This review discusses the relevance of PI for the field of transfusion medicine and describes the available and emerging PI technologies that can be used to treat cellular blood products such as platelet and red blood cell units. In collaboration with the French medical device manufacturer Macopharma, the German Red Cross Blood Services developed a new UVC light-based PI method for platelet units, which is currently being investigated in clinical trials.