Therapeutic efficacy and safety of pathogen-reduced platelet components: Results of a meta-analysis of randomized controlled trials.

BACKGROUND AND OBJECTIVES: Clinical efficacy and safety of pathogen-reduced platelet concentrates (PR-PCs) concerning bleeding prevention are still debated despite conclusive real-world data from multiple countries where PR-PCs are transfused routinely. We performed a meta-analysis of randomized controlled trials (RCTs) comparing the clinical efficacy and safety of conventional platelet components (PCs) and PR-PCs prepared with the amotosalen/ultraviolet A light (INTERCEPT platelet concentrate [I-PC]) or riboflavin/ultraviolet light (Mirasol platelet concentrate [M-PC]) technologies, transfused in thrombocytopenic adult patients. MATERIALS AND METHODS: A literature search was conducted, and 10 RCTs met the criteria for inclusion in this meta-analysis. Summary odds ratios (ORs) of clinically significant bleeding (World Health Organization [WHO] bleeding grade ≥2), severe bleeding (WHO bleeding score ≥3) and all-cause mortality were calculated. RESULTS: The use of I-PC was not associated with an increase in the OR of clinically significant bleeding when compared to non-treated PCs (OR, 1.12; 95% CI: 0.89-1.41; p = 0.33), whereas transfusions with M-PC showed an increase in clinically significant bleeding (OR, 1.34; 95% CI: 1.03-1.75; p = 0.03). The OR of severe bleeding did not increase with either I-PC or M-PC (OR 0.88; 95% CI: 0.59-1.31; p = 0.52 for I-PC; OR 1.25; 95% CI: 0.66-2.37; p = 0.49 for M-PC). In the case of all-cause mortality, compared to non-treated PC, I-PC showed an OR of 0.61 (95% CI: 0.36-1.04; p = 0.07), and M-PC showed an OR of 3.04 (95% CI: 0.81-11.47; p = 0.1). CONCLUSION: No differences were observed concerning the clinical efficacy and safety of overall PR-PCs when compared to non-treated PCs. However, differences are evident when analysing platelets prepared with the two PR technologies independently.

Spectroscopic view on the interaction between the psoralen derivative amotosalen and DNA.

Psoralens are eponymous for PUVA (psoralen plus UV-A radiation) therapy, which inter alia can be used to treat various skin diseases. Based on the same underlying mechanism of action, the synthetic psoralen amotosalen (AMO) is utilized in the pathogen reduction technology of the INTERCEPT® Blood System to inactivate pathogens in plasma and platelet components. The photophysical behavior of AMO in the absence of DNA is remarkably similar to that of the recently studied psoralen 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT). By means of steady-state and time-resolved spectroscopy, intercalation and photochemistry of AMO and synthetic DNA were studied. AMO intercalates with a higher affinity into A,T-only DNA (KD = 8.9 × 10-5 M) than into G,C-only DNA (KD = 6.9 × 10-4 M). AMO covalently photobinds to A,T-only DNA with a reaction quantum yield of ΦR = 0.11. Like AMT, it does not photoreact following intercalation into G,C-only DNA. Femto- and nanosecond transient absorption spectroscopy reveals the characteristic pattern of photobinding to A,T-only DNA. For AMO and G,C-only DNA, signatures of a photoinduced electron transfer are recorded.

Longitudinal analysis of annual national hemovigilance data to assess pathogen reduced platelet transfusion trends during conversion to routine universal clinical use and 7-day storage.

BACKGROUND: France converted to universal pathogen reduced (PR; amotosalen/UVA) platelets in 2017 and extended platelet component (PC) shelf-life from 5- to 7-days in 2018 and 2019. Annual national hemovigilance (HV) reports characterized longitudinal PC utilization and safety over 11 years, including several years prior to PR adoption as the national standard of care. METHODS: Data were extracted from published annual HV reports. Apheresis and pooled buffy coat [BC] PC use was compared. Transfusion reactions (TRs) were stratified by type, severity, and causality. Trends were assessed for three periods: Baseline (2010-14; ~7% PR), Period 1 ([P1] 2015-17; 8%-21% PR), and Period 2 ([P2] 2018-20; 100% PR). RESULTS: PC use increased by 19.1% between 2010 and 2020. Pooled BC PC production increased from 38.8% to 68.2% of total PCs. Annual changes in PCs issued averaged 2.4% per year at baseline, -0.02% (P1) and 2.8% (P2). The increase in P2 coincided with a reduction in the target platelet dose and extension to 7-day storage. Allergic reactions, alloimmunization, febrile non-hemolytic TRs, immunologic incompatibility, and ineffective transfusions accounted for >90% of TRs. Overall, TR incidence per 100,000 PCs issued declined from 527.9 (2010) to 345.7 (2020). Severe TR rates declined 34.8% between P1-P2. Forty-six transfusion-transmitted bacterial infections (TTBI) were associated with conventional PCs during baseline and P1. No TTBI were associated with amotosalen/UVA PCs. Infections with Hepatitis E (HEV) a non-enveloped virus resistant to PR, were reported in all periods. DISCUSSION: Longitudinal HV analysis demonstrated stable PC utilization trends with reduced patient risk during conversion to universal 7-day amotosalen/UVA PCs.

Biochemical and functional characteristics of stored (double-dose) buffy-coat platelet concentrates treated with amotosalen and a prototype UVA light-emitting diode illuminator.

BACKGROUND: Pathogen reduction of platelet concentrates (PCs) using amotosalen and broad-spectrum UVA illumination contributes to the safety of platelet transfusion by reducing the risk of transfusion-transmitted infections. We evaluated the in vitro quality of stored buffy-coat (BC) PCs treated with amotosalen and a prototype light-emitting diode (LED) illuminator. METHODS: Double-dose BC-PCs collected into PAS-III/plasma or SSP+ /plasma (55/45%) were treated with amotosalen in combination with either conventional UVA lamps (INT100 Illuminator 320-400 nm) or LED illuminators at 350 nm. Platelet quality and function were evaluated over 7 days. RESULTS: Platelet counts were conserved during storage in all groups, as was platelet swirling without appearance of macroscopic aggregates. Integrin αIIbß3 and glycoprotein (GP) VI expression remained stable, whereas GPIbα and GPV declined similarly in all groups. UV lamp- and LED-treated PCs displayed similar glucose consumption, lactate generation, and pH variation. Comparable spontaneous and residual P-selectin and phosphatidylserine exposure, activated αIIbß3 exposure, mitochondrial membrane potential, lactate dehydrogenase release, and adhesive properties under flow conditions were observed during storage. The use of SSP+ /plasma compared with PAS-III/plasma better preserved most of these parameters, especially during late storage, irrespective of the type of illuminator. CONCLUSION: Replacing the UVA lamp for photochemical treatment by LED illuminators had no impact on platelet metabolism, spontaneous activation, apoptosis or viability, or on the in vitro function of BC-PCs stored for 7 days in SSP+ or PAS-III/plasma. These findings support improved procedures for the pathogen reduction and storage of PCs, to ensure transfusion safety and retention of platelet functional properties.

Evaluation of amotosalen and UVA pathogen-reduced apheresis platelets after 7-day storage.

BACKGROUND: Amotosalen/UVA pathogen-reduced platelet components (PRPCs) with storage up to 7 days are standard of care in France, Switzerland, and Austria. PRPCs provide effective hemostasis with reduced risk of transfusion-transmitted infections and transfusion-associated graft versus host disease, reduced wastage and improved availability compared with 5-day-stored PCs. This study evaluated the potency of 7-day PRPCs by in vitro characterization and in vivo pharmacokinetic analysis of autologous PCs. STUDY DESIGN AND METHODS: The in vitro characteristics of 7-day-stored apheresis PRPCs suspended in 100% plasma or 65% platelet additive solution (PAS-3)/35% plasma, thrombin generation, and in vivo radiolabeled post-transfusion recovery and survival of 7-day-stored PRPCs suspended in 100% plasma were compared with either 7-day-stored or fresh autologous conventional platelets. RESULTS: PRPCs after 7 days of storage maintained pH, platelet dose, in vitro physiologic characteristics, and thrombin generation when compared to conventional 7-day PCs. In vivo, the mean post-transfusion survival was 151.4 ± 20.1 h for 7-day PRPCs in 100% plasma (Test) versus 209.6 ± 13.9 h for the fresh autologous platelets (Control), (T-ΔC: 72.3 ± 8.8%: 95% confidence interval [CI]: 68.5, 76.1) and mean 24-h post-transfusion recovery 37.6 ± 8.4% for Test versus 56.8 ± 9.2% for Control (T-ΔC: 66.2 ± 11.2%; 95% CI: 61.3, 71.1). DISCUSSION: PRPCs collected in both 100% plasma as well as 65% PAS-3/35% plasma and stored for 7 days retained in vitro physiologic characteristics. PRPCs stored in 100% plasma for 7 days retained in vivo survival. Lower in vivo post-radiolabeled autologous platelet recovery is consistent with reported reduced count increments for allogenic transfusion.

Removal of citrate from PAS-III additive solution improves functional and biochemical characteristics of buffy-coat platelet concentrates stored for 7 days, with or without INTERCEPT pathogen reduction.

BACKGROUND: Deterioration in quality of platelet concentrates (PCs) during storage results from the appearance of storage lesions affecting the hemostatic functions and posttransfusion survival of platelets. These lesions depend on the preparation and pathogen inactivation methods used, duration of storage, and platelet additive solutions (PASs) present in storage bags. METHODS: We investigated the effects of citrate contained in third-generation PAS (PAS-III) on storage lesions in buffy-coat PCs with or without photochemical (amotosalen-ultraviolet A) treatment over 7 days. RESULTS: Platelet counts were conserved in all groups during storage, as was platelet swirling without appearance of macroscopic aggregates. Glycoprotein (GP) IIbIIIa and GPVI expression remained stable, whereas GPIbα declined similarly in all groups during storage. Removal of citrate from PAS-III, resulting in global reduction of citrate from 11 to 5 mM, led to a significant decrease in glucose consumption, which largely countered a modest deleterious effect of photochemical treatment. Citrate reduction also resulted in decreased lactate generation and better maintenance of pH during storage, while photochemical treatment had no impact on these parameters. Moreover, citrate-free storage significantly reduced exposure of P-selectin and the apoptosis signal phosphatidylserine, thereby abolishing the activating effect of photochemical treatment on both parameters. Citrate reduction benefited platelet aggregation to various agonists up to Day 7, whereas PCT had no impact on these responses. CONCLUSION: Removal of citrate from PAS-III has a beneficial impact on platelet metabolism, spontaneous activation, and apoptosis, and improves platelet aggregation, irrespective of photochemical treatment, which should allow transfusion of platelets with better and longer-lasting functional properties.

Amotosalen and ultraviolet A light treatment efficiently inactivates severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in human plasma.

BACKGROUND AND OBJECTIVES: During the ongoing pandemic of COVID-19, SARS-CoV-2 RNA was detected in plasma and platelet products from asymptomatic blood donors, raising concerns about potential risk of transfusion transmission, also in the context of the current therapeutic approach utilizing plasma from convalescent donors. The objective of this study was to assess the efficacy of amotosalen/UVA light treatment to inactivate SARS-CoV-2 in human plasma to reduce the risk of potential transmission through blood transfusion. METHODS: Pools of three whole-blood-derived human plasma units (630-650 ml) were inoculated with a clinical SARS-CoV-2 isolate. Spiked units were treated with amotosalen/UVA light (INTERCEPT Blood System™) to inactivate SARS-CoV-2. Infectious titres and genomic viral load were assessed by plaque assay and real-time quantitative PCR. Inactivated samples were subject to three successive passages on permissive tissue culture to exclude the presence of replication-competent viral particles. RESULTS: Inactivation of infectious viral particles in spiked plasma units below the limit of detection was achieved by amotosalen/UVA light treatment with a mean log reduction of >3·32 ± 0·2. Passaging of inactivated samples on permissive tissue showed no viral replication even after 9 days of incubation and three passages, confirming complete inactivation. The treatment also inhibited NAT detection by nucleic acid modification with a mean log reduction of 2·92 ± 0·87 PFU genomic equivalents. CONCLUSION: Amotosalen/UVA light treatment of SARS-CoV-2 spiked human plasma units efficiently and completely inactivated >3·32 ± 0·2 log of SARS-CoV-2 infectivity, showing that such treatment could minimize the risk of transfusion-related SARS-CoV-2 transmission.

Impact of pathogen reduction methods on immunological properties of the COVID-19 convalescent plasma.

BACKGROUND AND OBJECTIVES: COVID-19 convalescent plasma is an experimental treatment against SARS-CoV-2. The aim of this study is to assess the impact of different pathogen reduction methods on the levels and virus neutralizing activity of the specific antibodies against SARS-CoV2 in convalescent plasma. MATERIALS AND METHODS: A total of 140 plasma doses collected by plasmapheresis from COVID-19 convalescent donors were subjected to pathogen reduction by three methods: methylene blue (M)/visible light, riboflavin (R)/UVB and amotosalen (A)/UVA. To conduct a paired comparison, individual plasma doses were divided into 2 samples that were subjected to one of these methods. The titres of SARS-CoV2 neutralizing antibodies (NtAbs) and levels of specific immunoglobulins to RBD, S- and N-proteins of SARS-CoV-2 were measured before and after pathogen reduction. RESULTS: The methods reduced NtAbs titres differently: among units with the initial titre 80 or above, 81% of units remained unchanged and 19% decreased by one step after methylene blue; 60% were unchanged and 40% decreased by one step after amotosalen; after riboflavin 43% were unchanged and 50% (7%, respectively) had a one-step (two-step, respectively) decrease. Paired two-sample comparisons (M vs. A, M vs. R and A vs. R) revealed that the largest statistically significant decrease in quantity and activity of the specific antibodies resulted from the riboflavin treatment. CONCLUSION: Pathogen reduction with methylene blue or with amotosalen provides the greater likelihood of preserving the immunological properties of the COVID-19 convalescent plasma compared to riboflavin.

Plasma pooling in combination with amotosalen/UVA pathogen inactivation to increase standardisation and safety of therapeutic plasma units.

OBJECTIVES: Assessment of the impact of pooling five single-donor plasma (SDP) units to obtain six pathogen-reduced therapeutic plasma (PTP) units on standardisation and the retention of labile coagulation factors. BACKGROUND: SDP shows a high inter-donor variability with potential implications for the clinical treatment outcome. Additionally, there is still an existing risk for window-period transmissions of blood borne pathogens including newly emerging pathogens. METHODS/MATERIALS: Five ABO-identical SDP units were pooled, treated with the INTERTCEPT™ Blood System (Cerus Corporation, U.S.A.) and split into six PTP units which were frozen and thawed after 30 days. The variability in volume, labile coagulation factor retention and activity was assessed. RESULTS: The variability of volumes between the PTP units was reduced by 46% compared to SDP units. The variability in coagulation factor content between the PTP units was reduced by 63% compared to SDP units. Moderate, but significant losses of coagulation factors (except for vWF) were observed in PTPs compared to SDPs. CONCLUSION: The pooling of five SDP units to obtain six PTP units significantly increases product standardisation with potential implications for safety, economics as well as transfusion-transmitted pathogen safety, making it an interesting alternative to quarantine SDP (qSDP) and pathogen-reduced SDP.

Pathogen reduction with amotosalen/UVA reduces platelet refractoriness in a dog platelet transfusion model.

BACKGROUND AND OBJECTIVES: Pathogen reduction of donor platelets with amotosalen/UVA has been shown to effectively inactivate pathogens and also contaminating white blood cells (WBCs). We wanted to determine whether WBC inactivation could also decrease alloimmune refractoriness to donor platelets. MATERIALS AND METHODS: Platelets were prepared from a donor dog's whole blood, and the platelets were either transfused without modification [standard (STD) platelets] or treated with amotosalen/UVA under conditions modelling the amotosalen/UVA Blood System for human platelets (APR) using either 4 or 3 J/cm2 of UVA exposure. Platelets were transfused weekly from a single donor dog for 8 weeks or until the recipient dog became refractory to their donor's platelets. Antibody samples were drawn weekly and tested against the donor dog's platelets and WBCs (CD8 and B cells). RESULTS: Only 1/7 (14%) dogs that received STD platelets accepted 8 weeks of donor transfusions. Following APR 4 J/cm2 donor transfusions, 3/9 (33%) recipients accepted their donor's transfusions, but only one recipient remained antibody negative. Following APR 3 J/cm2 donor transfusions, the same dose as used for human platelet transfusions, 7/10 (70%) recipients accepted their donor's transfusions, but only two remained antibody negative. CONCLUSION: As a very high percentage of recipient dogs (70%) accepted APR 3 J/cm2 donor transfusions, these data suggest that preventing alloimmune platelet refractoriness may be another benefit of pathogen reduction using amotosalen/UVA.

Amotosalen and ultraviolet A light efficiently inactivate MERS-coronavirus in human platelet concentrates.

OBJECTIVE: This study aimed to assess the efficacy of the INTERCEPT™ Blood System [amotosalen/ultraviolet A (UVA) light] to reduce the risk of Middle East respiratory syndrome-Coronavirus (MERS-CoV) transmission by human platelet concentrates. BACKGROUND: Since 2012, more than 2425 MERS-CoV human cases have been reported in 27 countries. The infection causes acute respiratory disease, which was responsible for 838 deaths in these countries, mainly in Saudi Arabia. Viral genomic RNA was detected in whole blood, serum and plasma of infected patients, raising concerns of the safety of blood supplies, especially in endemic areas. METHODS: Four apheresis platelet units in 100% plasma were inoculated with a clinical MERS-CoV isolate. Spiked units were then treated with amotosalen/UVA to inactivate MERS-CoV. Infectious and genomic viral titres were quantified by plaque assay and quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR). Inactivated samples were successively passaged thrice on Vero E6 cells to exclude the presence of residual replication-competent viral particles in inactivated platelets. RESULTS: Complete inactivation of MERS-CoV in spiked platelet units was achieved by treatment with Amotosalen/UVA light with a mean log reduction of 4·48 ± 0·3. Passaging of the inactivated samples in Vero E6 showed no viral replication even after nine days of incubation and three passages. Viral genomic RNA titration in inactivated samples showed titres comparable to those in pre-treatment samples. CONCLUSION: Amotosalen and UVA light treatment of MERS-CoV-spiked platelet concentrates efficiently and completely inactivated MERS-CoV infectivity (>4 logs), suggesting that such treatment could minimise the risk of transfusion-related MERS-CoV transmission.

Impact of platelet pathogen inactivation on blood component utilization and patient safety in a large Austrian Regional Medical Centre.

BACKGROUND: In clinical studies, pathogen inactivation (PI) of platelet concentrates (PC) with amotosalen and UVA light did not impact patient risk for haemorrhage but may affect transfusion frequency and component utilization. We evaluated the influence of platelet PI on PC, red cell concentrate (RCC) and plasma use and safety in routine practice in a large regional hospital. STUDY DESIGN AND METHODS: Comparative effectiveness of conventional vs. PI-treated PC was analysed during two 21-month periods, before and after PI implementation. RESULTS: Similar numbers of patients were transfused in the pre-PI (control, 1797) and post-PI (test, 1694) periods with comparable numbers of PC (8611 and 7705, respectively). The mean numbers of PC per patient transfused (4·8 vs. 4·5, P = 0·43) were not different but days of PC support (5·9 vs. 5·0, P < 0·01) decreased. Most patients received RCC (86·8% control vs. 84·8% test, P = 0·90) with similar mean numbers transfused (10·8 vs. 10·2 RCC, P = 0·22), and fewer patients (55·4% control vs. 44·7% test, P < 0·01) received less plasma units (mean 9·9 vs. 7·8, respectively, P < 0·01) in the test period. The frequencies of transfusion-related adverse events (AE) were comparable (1·3% vs. 1·4%, P = 0·95). Analysis of haematology-oncology (522 control, 452 test), cardiac surgery (739 control, 711 test), paediatric (157 control, 130 test) and neonate (23 control, 20 test) patients revealed no increase in PC, plasma and RCC utilization, or AE. CONCLUSION: Component utilization and patient safety were not impacted by adoption of PI for PC. RCC use per patient was comparable, suggestive of no increase in significant bleeding.

Patient outcomes and amotosalen/UVA-treated platelet utilization in massively transfused patients.

BACKGROUND: Amotosalen/UVA-treated platelet concentrates (PCs) have demonstrated efficacy for treating and preventing bleeding in clinical trials and in routine use; however, most studies were performed in haematology/oncology patients. We investigated efficacy during massive transfusion (MT) in general hospitalized patients. METHODS: Universal amotosalen/UVA treatment (INTERCEPT Blood System) of platelets was introduced at a large Austrian medical centre. We performed a retrospective cohort analysis comparing component use, in-hospital mortality and length of stay after MT that included platelet transfusion, for two periods (21 months each) before and after implementation. RESULTS: A total of 306 patients had MT. Patients were mostly male (74%) and ≥18 years old (99%), including 93 liver transplant, 97 cardiac or vascular surgery and 51 trauma patients. There were no differences in demographics between the periods. Component use on the day and within 7 days of the MT event was unchanged post-IBS implementation, except trauma patients received fewer RBCs on the day. The mean ratio of RBC:platelets:plasma on the day of the MT was close to 1:1:1 in both periods, except for liver transplants with MT who received more plasma components. Overall, in-hospital mortality (preimplementation = 27·6% vs. postimplementation = 24·0%; P = 0·51) and median time to discharge (preimplementation = 27 vs. postimplementation = 23 days; P = 0·37) did not change, except for cardiac and vascular surgery patients who were discharged earlier. CONCLUSION: The introduction of amotosalen/UVA-treated, pathogen-reduced PC did not adversely affect clinical outcomes in massively transfused patients in terms of blood product usage, in-hospital mortality and length of stay for a range of clinical indications for platelet transfusion support.

Pathogen inactivation of double-dose buffy-coat platelet concentrates photochemically treated with amotosalen and UVA light: preservation of in vitro function.

BACKGROUND: The INTERCEPT Blood System for Platelets (PLT) utilizes amotosalen (S-59) in combination with ultraviolet A (UVA) light to inactivate viruses, bacteria, protozoa and leucocytes that may contaminate PLT concentrates. However, limited data are available on the quality of INTERCEPT-treated double-dose (DD) buffy-coat (BC) PLT units allowing a single treatment procedure to produce two pathogen-inactivated PLT units for transfusion. STUDY DESIGN AND METHODS: The objective of this study was to evaluate potential in vitro effects of the INTERCEPT treatment on pools of 7 BCs as compared to untreated units. Functional, phenotypic and mitochondrial properties of DD BC PLTs during storage over 7 days were studied. RESULTS: For some parameters measured, small yet significant differences were observed including PLT count (P < 0·05), pH, pCO2 and glucose concentration. Throughout storage, no significant differences were observed in ATP levels, ESC, HSR reactivity and CD62P expression. Similarly, no differences were observed in the expression of PAC-1, CD42b and PECAM-1 at any time-points. The mitochondrial membrane potential (MMP) determined by JC-1-labelling was well maintained until day 7 in all treated and untreated units (>90%). The release of sCD40L increased over time (P < 0·01) in all units but without any significant differences between treated and untreated PLTs. CONCLUSION: Our data demonstrate that photochemical pathogen inactivation of DD-BC PLT concentrates with the INTERCEPT Blood System had no influence on the PLT in vitro quality over the 7 day of storage. However, whether in vivo efficacy of INTERCEPT-treated PLTs is affected may require clinical evaluation.

A prospective, active haemovigilance study with combined cohort analysis of 19,175 transfusions of platelet components prepared with amotosalen-UVA photochemical treatment.

BACKGROUND AND OBJECTIVES: A photochemical treatment process (PCT) utilizing amotosalen and UVA light (INTERCEPT(™) Blood System) has been developed for inactivation of viruses, bacteria, parasites and leucocytes that can contaminate blood components intended for transfusion. The objective of this study was to further characterize the safety profile of INTERCEPT-treated platelet components (PCT-PLT) administered across a broad patient population. MATERIALS AND METHODS: This open-label, observational haemovigilance programme of PCT-PLT transfusions was conducted in 21 centres in 11 countries. All transfusions were monitored for adverse events within 24 h post-transfusion and for serious adverse events (SAEs) up to 7 days post-transfusion. All adverse events were assessed for severity (Grade 0-4), and causal relationship to PCT-PLT transfusion. RESULTS: Over the course of 7 years in the study centres, 4067 patients received 19,175 PCT-PLT transfusions. Adverse events were infrequent, and most were of Grade 1 severity. On a per-transfusion basis, 123 (0.6%) were classified an acute transfusion reaction (ATR) defined as an adverse event related to the transfusion. Among these ATRs, the most common were chills (77, 0.4%) and urticaria (41, 0.2%). Fourteen SAEs were reported, of which 2 were attributed to platelet transfusion (<0.1%). No case of transfusion-related acute lung injury, transfusion-associated graft-versus-host disease, transfusion-transmitted infection or death was attributed to the transfusion of PCT-PLT. CONCLUSION: This longitudinal haemovigilance safety programme to monitor PCT-PLT transfusions demonstrated a low rate of ATRs, and a safety profile consistent with that previously reported for conventional platelet components.

Independent evaluation of tolerance of therapeutic plasma inactivated by amotosalen-HCl-UVA (Intercept ™) over a 5-year period of extensive delivery.

Amotosalen-HCl-UVA (AI) is a process to inactivate pathogens in therapeutic plasma (FFP). Tolerance is the main residual issue in FFP transfusion, and only large series observations are powered enough to identify significantly elevated levels of hazards. We report here on 15,133 new transfusions of AI-FFP, over the previously published 36,035, which in all represents one of the largest series observed by means of a highly standardized surveillance (51.168 observations). There is no noticeable difference in terms of tolerance of AI-FFP compared to 5875 transfusions of Quarantine (Q)-FFP. There was no significant difference in terms of advance events, between the two types of FFP (P = 0.98); further, no difference was recorded either when the total number of AI-FFP (51,168) was compared to the corresponding number of Q-FFP (5875; P = 0.62).

RND Pump-Mediated Efflux of Amotosalen, a Compound Used in Pathogen Inactivation Technology to Enhance Safety of Blood Transfusion Products, May Compromise Its Gram-Negative Anti-Bacterial Activity.

Pathogen inactivation is a strategy to improve the safety of transfusion products. The only pathogen reduction technology for blood products currently approved in the US utilizes a psoralen compound, called amotosalen, in combination with UVA light to inactivate bacteria, viruses, and protozoa. Psoralens have structural similarity to bacterial multidrug efflux pump substrates. As these efflux pumps are often overexpressed in multidrug-resistant pathogens, we tested whether contemporary drug-resistant pathogens might show resistance to amotosalen and other psoralens based on multidrug efflux mechanisms through genetic, biophysical, and molecular modeling analysis. The main efflux systems in Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa are tripartite resistance-nodulation-cell division (RND) systems, which span the inner and outer membranes of Gram-negative pathogens, and expel antibiotics from the bacterial cytoplasm into the extracellular space. We provide evidence that amotosalen is an efflux substrate for the E. coli AcrAB, Acinetobacter baumannii AdeABC, and P. aeruginosa MexXY RND efflux pumps. Furthermore, we show that the MICs for contemporary Gram-negative bacterial isolates for these species and others in vitro approached and exceeded the concentration of amotosalen used in the approved platelet and plasma inactivation procedures. These findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens. IMPORTANCE Pathogen inactivation is a strategy to enhance the safety of transfused blood products. We identify the compound, amotosalen, widely used for pathogen inactivation, as a bacterial multidrug efflux substrate. Specifically, experiments suggest that amotosalen is pumped out of bacteria by major efflux pumps in E. coli, Acinetobacter baumannii, and Pseudomonas aeruginosa. Such efflux pumps are often overexpressed in multidrug-resistant pathogens. Importantly, the MICs for contemporary multidrug-resistant Enterobacterales, Acinetobacter baumannii, Pseudomonas aeruginosa, Burkholderia spp., and Stenotrophomonas maltophilia isolates approached or exceeded the amotosalen concentration used in approved platelet and plasma inactivation procedures, potentially as a result of efflux pump activity. Although there are important differences in methodology between our experiments and blood product pathogen inactivation, these findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens.

Inactivation of SARS-CoV-2 in All Blood Components Using Amotosalen/Ultraviolet A Light and Amustaline/Glutathione Pathogen Reduction Technologies.

No cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transfusion-transmitted infections (TTI) have been reported. The detection of viral RNA in peripheral blood from infected patients and blood components from infected asymptomatic blood donors is, however, concerning. This study investigated the efficacy of the amotosalen/UVA light (A/UVA) and amustaline (S-303)/glutathione (GSH) pathogen reduction technologies (PRT) to inactivate SARS-CoV-2 in plasma and platelet concentrates (PC), or red blood cells (RBC), respectively. Plasma, PC prepared in platelet additive solution (PC-PAS) or 100% plasma (PC-100), and RBC prepared in AS-1 additive solution were spiked with SARS-CoV-2 and PR treated. Infectious viral titers were determined by plaque assay and log reduction factors (LRF) were determined by comparing titers before and after treatment. PR treatment of SARS-CoV-2-contaminated blood components resulted in inactivation of the infectious virus to the limit of detection with A/UVA LRF of >3.3 for plasma, >3.2 for PC-PAS-plasma, and >3.5 for PC-plasma and S-303/GSH LRF > 4.2 for RBC. These data confirm the susceptibility of coronaviruses, including SARS-CoV-2 to A/UVA treatment. This study demonstrates the effectiveness of the S-303/GSH treatment to inactivate SARS-CoV-2, and that PRT can reduce the risk of SARS-CoV-2 TTI in all blood components.

Assessment of dengue virus inactivation in random donor platelets using amotosalen and ultraviolet A illumination.

OBJECTIVES: The study objective was evaluation of amotosalen and ultraviolet A (UVA) illumination-based inactivation of dengue virus (DENV) in blood platelets. MATERIALS AND METHODS: Whole blood was collected from healthy donors and platelet concentrates were prepared at a tertiary care hospital in Gurugram, India. Platelet units collected from five blood group matched individuals were pooled and spiked with DENV. The spiked platelet units were subjected to amotosalen treatment followed by UVA illumination, to evaluate the efficiency of this method for viral inactivation. The treated platelet units were evaluated for the presence of infectious DENV. Amotosalen levels were quantified in the treated samples using high-performance liquid chromatography. RESULTS: The presence of replicating DENV was not observed in spiked platelet units treated with amotosalen and UVA illumination, whereas untreated units contained actively replicating DENV. Amotosalen levels were found to be in the permissible range after photochemical inactivation. CONCLUSIONS: Amotosalen/UVA pathogen inactivation treatment showed efficient inactivation of DENV in platelet components. Therefore, it seems to be a promising method for mitigating the risk of dengue transmission through transfusion of potentially contaminated platelet components in dengue-endemic countries such as India.

Efficient inactivation of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in human apheresis platelet concentrates with amotosalen and ultraviolet A light.

OBJECTIVES: The detection of SARS-CoV-2 RNA in blood and platelet concentrates from asymptomatic donors, and the detection of viral particles on the surface and inside platelets during in vitro experiments, raised concerns over the potential risk for transfusion-transmitted-infection (TTI). The objective of this study was to assess the efficacy of the amotosalen/UVA pathogen reduction technology for SARS-CoV-2 in human platelet concentrates to mitigate such potential risk. MATERIAL AND METHODS: Five apheresis platelet units in 100% plasma were spiked with a clinical SARS-CoV-2 isolate followed by treatment with amotosalen/UVA (INTERCEPT Blood System), pre- and posttreatment samples were collected as well as untreated positive and negative controls. The infectious viral titer was assessed by plaque assay and the genomic titer by quantitative RT-PCR. To exclude the presence of infectious particles post-pathogen reduction treatment below the limit of detection, three consecutive rounds of passaging on permissive cell lines were conducted. RESULTS: SARS-CoV-2 in platelet concentrates was inactivated with amotosalen/UVA below the limit of detection with a mean log reduction of>3.31±0.23. During three consecutive rounds of passaging, no viral replication was detected. Pathogen reduction treatment also inhibited nucleic acid detection with a log reduction of>4.46±0.51 PFU equivalents. CONCLUSION: SARS-CoV-2 was efficiently inactivated in platelet concentrates by amotosalen/UVA treatment. These results are in line with previous inactivation data for SARS-CoV-2 in plasma as well as MERS-CoV and SARS-CoV-1 in platelets and plasma, demonstrating efficient inactivation of human coronaviruses.