Takemoto, Clifford M.

Abstract Background Red blood cell (RBC) transfusion may be lifesaving, however transfusion-transmitted infections (TTI) and transfusion-associated graft-versus-host disease (TA-GVHD) still pose a threat despite current donor selection and testing requirements. Amustaline (S-303)/glutathione (GSH) pathogen reduction (PR) is designed to inactivate infectious microbes and leukocytes in RBCs. The RedeS study evaluates the safety and efficacy of amustaline/GSH PR-RBCs compared to conventional RBCs in a broad spectrum of patients requiring acute and/or repeated RBC transfusion support. Methods RedeS is a Phase 3, prospective, multi-center, randomized, double-blind, active-controlled, parallel-design study, with a 6-month extension option to evaluate patients requiring repeated transfusions including red cell exchange (RCE).Eligible subjects will be stratified according to site, baseline bleeding status and participation in the extension period. The study arms include a transfusion period of 28-days for anemia with any bleeding or non-bleeding patients or a 28-day+6-month extension for non-bleeding patients with chronic anemia requiring repeated simple transfusions, or for patients with sickle cell disease (SCD) expected to receive three RCE procedures. The study will seek to enroll 600-800 subjects in the overall safety analysis, including ~140 repeatedly-transfused subjects in the 6-month extension including up to 30 subjects receiving three RCE procedures. The primary safety endpoints are the proportion of patients with any treatment-emergent adverse events (TEAEs) related to study RBC transfusion through 28 days after the last study transfusion, and the proportion of patients with treatment-emergent antibodies with confirmed specificity to PR-RBCs. The primary efficacy endpoint is the hemoglobin (Hb) increment in subjects who are non-bleeding at baseline, adjusted for the grams of Hb transfused and averaged over multiple transfusions. With 352 evaluable transfused non-bleeding subjects (176 per treatment group) from either arm, the study will have 80% power to demonstrate non-inferiority, defined as a Hb increment treatment difference of no more than 15% of the Control group mean, assuming a Control arm coefficient of variation of 50%. Discussion RedeS will characterize the safety of amustaline/GSH PR-RBCs and is designed to demonstrate the non-inferiority of PR-RBCs to conventional RBCs with respect to Hb increment, a common pragmatic clinical assessment of RBC transfusion effectiveness.

Abstract Introduction: The Duffy null variant (genotype or phenotype) is associated with lower circulating absolute neutrophil counts (ANC) without increased risk for infection. It is found in ~66% of people identifying as Black or African American vs <1% of people of Asian or European ancestry. Many ANC reference intervals (RI) are not representative of the Duffy null population. There are no adult Duffy null WBC RI and no pediatric Duffy null ANC or WBC RI. Thus, we aimed to assess Duffy null ANC and WBC distributions as well as develop WBC and ANC RI for adults and pediatrics. Methods: Twenty-three sites across the United States collected samples with all sites excluding participants with conditions or medications that could impact ANC or WBC. Only Duffy null participants were included. Sex, race, ethnicity, age, sample collection type, practice setting, Duffy testing method, ANC, and WBC were recorded. The non-parametric method for determining lower limit of normal (LLN), upper limit of normal (ULN), and 90% confidence intervals (CI) around the limits was performed according to the Clinical and Laboratory Standards Institute guidelines. Specific ULN and LLN are not reported as these are preliminary data. The Mann-Whitney U test was used to compare sex and prior data; differences by age groups were assessed with Kruskal-Wallis test. Results: 316 participants 18+ years-old (y/o) were assessed of whom 62.3% (n=197) are female, 97.5% (n=308) identified as Black or African American, and 94.9% (n=300) identified as non-Hispanic. Median age was 47 y/o (IQR: 32-60.5). Median ANC was 2600/uL (IQR: 1860-3530; range: 400-7400); 28.6% (n=90) of participants had ANC <2000/uL, 13.6% (n=43) had ANC <1500/uL, and 2.5% (n=8) had <1000/uL. The 90% CI around the LLN was 810-1070/uL and 5570-7130/uL around the ULN. Consistent with prior data, there was a difference in median ANC by sex (male: 2400/uL; female: 2710/uL; p=0.02). There was no significant difference between this ANC data and previously published Duffy null ANC data (p=0.28). Median WBC was 5.4x109/L (IQR: 4.4-6.5; range: 2.10-11.64) with 4.1% (n=13) of participants with WBC <3.0x109/L. The 90% CI around the LLN is 3.68-4.30x109/L and 11.02-12.97x109/L around the ULN. 515 participants between 0-17 y/o were assessed with 51.8% (n=267) females, 94.8% (n=488) identified as Black or African American, and 94.0% (n=484) identified as non-Hispanic. Among pediatric participants, 56.8% (n=291) had ANC <2000/uL, 38.7% (n=198) had ANC <1500/uL, and 14.4% (n=74) had ANC <1000/uL. For those <1 y/o (n=29), median ANC was 950/uL (IQR: 840-1360; range: 111-3910). There are currently too few samples to predict ULN and LLN. Median WBC was 8.85x109/L (IQR: 7.03-10.16; range: 4.17-13.53). For those 1-5 y/o (n=143), median ANC was 1735/uL (IQR: 1100-2550; range: 207-5810) with a 90% CI around the LLN of 207-820/uL and 4020-5810/uL around the ULN. Median WBC was 6.72x109/L (IQR: 5.64-8.25; range: 3.68-12.97). For those 6-11 y/o (n=128), median ANC was 1590/uL (IQR: 1090-2470; range: 420-5490) with a 90% CI around the LLN of 420-910/uL and 4340-5490/uL around the ULN. Median WBC was 5.42x109/L (IQR: 4.45-6.70; range: 2.80-10.50). For those 12-17 y/o (n=215), median ANC was 2190/uL (IQR: 1460-2930; range: 204-5850) with a 90% CI around the LLN of 540-930/uL and 4350-5510/uL around the ULN. Median WBC was 5.06x109/L (IQR: 4.26-6.20; range of 2.04-9.91). There is a significant difference in ANC by age category (p<0.0001). Conclusion: This is the first report of healthy pediatric Duffy null ANC and WBC data and the first large-scale verification of adult Duffy null ANC and WBC data. Final RI are expected in September 2025. Among adults with the Duffy null phenotype, ANC LLN are likely between 810-1070/uL. Pediatric ANC LLN are likely as low as 207-820/uL (1-5 y/o), 420-910/uL (6-11 y/o), and 540-930/uL (12-17 y/o). These findings redefine “normal” as a significant proportion of healthy participants have ANC or WBC below current RI or below thresholds typically defined as disease. Limitations include heterogeneous sample populations and collection methods. Future analyses will assess differences between collection sites or methods. Ultimately, this work lays the foundation for a more scientifically sound and equitable approach to medical care by ensuring that RI accurately reflects health for the entire community. Healthcare systems are strongly encouraged to adopt Duffy null-specific ANC and WBC RI.