Summary Transfusion‐dependent thalassaemia (TDT) requires red blood cell concentrates (RBCC) to prevent complications of anaemia, but carries risk of infection. Pathogen reduction of RBCC offers potential to reduce infectious risk. We evaluated the efficacy and safety of pathogen‐reduced (PR) Amustaline‐Glutathione (A‐GSH) RBCC for TDT. Patients were randomized to a blinded 2‐period crossover treatment sequence for six transfusions over 8–10 months with Control and A‐GSH‐RBCC. The efficacy outcome utilized non‐inferiority analysis with 90% power to detect a 15% difference in transfused haemoglobin (Hb), and the safety outcome was the incidence of antibodies to A‐GSH‐PR‐RBCC. By intent to treat (80 patients), 12·5 ± 1·9 RBCC were transfused in each period. Storage durations of A‐GSH and C‐RBCC were similar (8·9 days). Mean A‐GSH‐RBCC transfused Hb (g/kg/day) was not inferior to Control (0·113 ± 0·04 vs. 0·111 ± 0·04, P = 0·373, paired t‐test). The upper bound of the one‐sided 95% confidence interval for the treatment difference from the mixed effects model was 0·005 g/kg/day, within a non‐inferiority margin of 0·017 g/kg/day. A‐GSH‐RBCC mean pre‐transfusion Hb levels declined by 6·0 g/l. No antibodies to A‐GSH‐RBCC were detected, and there were no differences in adverse events. A‐GSH‐RBCCs offer potential to reduce infectious risk in TDT with a tolerable safety profile.

BACKGROUND Plasma thawed and stored at 1 to 6°C for up to 5 days (thawed plasma [TP]) provides rapid availability in emergencies and reduces plasma waste, but it carries risks of coagulation factor loss or activation, bacterial outgrowth, and viral contamination. We characterized changes in amotosalen/ultraviolet A (UVA) light pathogen‐reduced, fresh‐frozen plasma (FFP) and plasma frozen within 24 hours (PF24) with post‐thaw storage. STUDY DESIGN AND METHODS Amotosalen/UVA light‐treated FFP and PF24 were thawed after approximately 3 to more than 12 months of frozen storage and held at 1 to 6°C for 5 days. Global assessments of coagulation and hemostatic, antithrombotic, and activation markers indicative of function were assessed. RESULTS Day 5, thawed amotosalen/UVA light‐treated FFP and PF24 contained levels of Factors II, V, VIII, IX, X, von Willebrand factor ristocetin cofactor (vWF:RCo), fibrinogen, antithrombin III (ATIII), protein C, and protein S similar to the levels measured in Day 5 TP, as described in the Circular of Information. Thrombin generation was robust on Day 5 (amotosalen/UVA: FFP = 1866 ± 402 nM/minute; PF24 = 1800 ± 277 nM/minute). Most factor activities on Day 5, including von Willebrand factor‐cleaving protease (ADAMTS‐13), were more than 90% of Day 0 values, except for known labile Factors V and VIII and protein S. All units contained greater than 0.4 IU/mL protein S and α2 plasmin inhibitor on Day 5. Global functional indices, including thrombin‐antithrombin complexes, nonactivated thromboplastin time, and thrombin‐generation peak height, did not indicate activation of the coagulation cascade, although isolated units showed raised levels of Factor VIIa and Complement 3a. CONCLUSION Amotosalen/UVA light‐treated FFP and PF24 demonstrated retention of procoagulant and antithrombotic activity after 5 days post‐thaw storage at 1 to 6°C.

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Introduction: Transfusion dependent thalassemia (TDT) requires regular transfusion of red cell concentrates (RBCC) to prevent the complications of anemia and excessive erythroid expansion. Despite donor testing, long-term transfusion has a substantial cumulative risk of transfusion-transmitted infection (TTI) due to undetected viruses, bacteria, and protozoa. Splenectomized (-S) TDT patients may have greater TTI morbidity than patients with spleens (+S); but may benefit from reduced use of red blood cell concentrates (RBCC) and reduced transfusion iron (Fe) loading. Pathogen reduction (PR) of RBCC with amustaline-glutathione (A-GSH) offers potential to reduce the risk of TTI. Objectives: To determine, the impact of PR-RBCC on hemoglobin (Hb) use, transfused Fe burden, incidence of RBC antibodies, and safety in -S and +S TDT patients. Methods: TDT patients at 3 sites, not stratified by spleen status, were prospectively enrolled in a two- period cross-over study randomized by sequence for RBCC preparation. Leukocyte reduced PR-RBCC (Test) were treated with 0.2mM amustaline and 20 mM GSH, re-suspended in saline-adenine-glucose mannitol (SAGM), and stored up to 35 days at 4°C. Leukocyte reduced conventional RBCC (Control) were suspended in SAGM and stored for up to 35 days at 4°C. Patients received 6 transfusions in each treatment sequence of Test or Control RBCC over ~ 5 months. Clinicians, blinded to RBCC Hb content and treatment sequence, ordered RBCC to maintain targeted pre-transfusion Hb thresholds of ~ 9-10 g/dL. Transfusion intervals or number of RBCC transfused were adjusted for clinical management. The primary efficacy outcome was assessed by non-inferiority (NI) analysis for Hb use (expressed as g/kg body weight/ day) using a pre-specified NI margin (≤ 15% of the observed Control mean). Results : Overall, mean (SD) Hb content (g) of 1024 Test RBCC = 54.6±5.9 (range: 39-73) and of 1008 Control RBCC = 55.6 ± 5.9 (range: 35-74) and varied widely. By intent-to-treat (ITT), 80 patients (40 +S and 40 -S) were transfused. For ITT patients (Table), the baseline Hb level (BL-Hb, g/dL) at first transfusion of Control periods was significantly lower than at Test periods; but the mean number of RBCC transfused, RBCC storage days, total Hb dose (g), and transfusion intervals were not significantly different for Test and Control. ITT analysis for all transfusion episodes showed Hb use for Test RBCC (0.110 g/kg/d) was not different from Control RBCC (0.112 g/kg/day). Non-inferiority was demonstrated (T-C = - 0.002 g/kg/d: 95% CI: -0.005, 0.001). ITT Test patients received a slightly lower mean total Hb dose (- 14g), and mean pre-transfusion Hb levels declined after 6 transfusions (9.4 to 8.8 g/dL). -S patients had lower BL-Hb levels (g/dL) than S+ patients in Test (9.2 vs 9.7) and Control (8.8 vs 9.2) periods (Table). -S patients received a lower mean total Hb dose of Test than Control RBCC (p=0.019); and had a decline in mean pre-transfusion Hb levels during Test periods (from 9.2 to 8.7 g/dL). Transfusion intervals were significantly longer for -S patients than +S patients with both Test and Control RBCC (p< 0.001 by 2-sample t test, respectively); and -S patients had lower Hb use than +S patients. However, Hb use of Test and Control RBCC was comparable within -S and + S cohorts (Table). Transfused Fe was less for -S patients for Test and Control RBCC. During 6 Test and 3 Control treatment periods, 8 patients (6 -S, 2 +S) had worsening anemia with pre-transfusion Hb levels (6.0-7.8 g/dL) substantially below the targeted transfusion threshold, but without evidence of hemolysis. Each of these patients received one or more Hb doses below the average RBCC transfusion episode dose (Test: 114.5 g) or (Control: 116.7 g); and 3 patients had concurrent infections. None of 80 patients had evidence of increased RBC clearance, developed antibodies to PR-RBCC, or had treatment emergent RBC alloantibodies in either treatment period. There were no differences in the overall safety profiles for Test and Control RBCC. Conclusions: Amustaline-GSH PR treatment of RBCCs offers the potential to reduce TTI risk without impacting Hb use or Fe burden in TDT. However, Hb content of Test and Control RBCC varies widely and may contribute to unexpected changes in pre-transfusion Hb levels. Spleen status affected Hb use comparably for PR-RBCC and Control RBCC, and remains an important factor in assessing transfusion requirements and Fe loading. Table. Table. Disclosures Aydinok: TERUMO: Research Funding; Cerus: Honoraria, Research Funding; CRISPR Tech: Other: DMC; Protagonist: Other: SSC; La Jolla Pharmaceuticals: Research Funding; Celgene: Research Funding; Novartis: Research Funding, Speakers Bureau. Piga:Apopharma: Honoraria, Research Funding; Celgene Corp: Membership on an entity's Board of Directors or advisory committees, Research Funding; La Jolla: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bluebird Bio: Honoraria; Acceleron: Research Funding; Novartis: Research Funding. Origa:Novartis: Honoraria; Bluebird Bio: Consultancy; Cerus Corporation: Research Funding; Apopharma: Honoraria. Mufti:Cerus Corporation: Employment, Equity Ownership. Erikson:Cerus Corporation: Employment, Equity Ownership. North:Cerus Corporation: Employment, Equity Ownership. Waldhaus:Cerus Corporation: Employment, Equity Ownership. Ernst:Cerus Corporation: Employment, Equity Ownership. Lin:Cerus Corporation: Employment, Equity Ownership. Huang:Cerus Corporation: Employment, Equity Ownership. Benjamin:Cerus Corporation: Employment, Equity Ownership. Corash:Cerus Corporation: Employment, Equity Ownership.