The overall objective of this study is to evaluate the effectiveness and safety of transfusing hypoxic red blood cells manufactured with the Hemanext ONE system in patients with sickle cell anemia. The Hemanext ONE device was cleared through the De Novo process in September 2023.

In this Direct-to-Phase II study, Hemanext Inc. will carry out a prospective, multi-center, single-blind, randomized, cross-over study in patients with Sickle Cell Anemia, comparing the efficacy of transfusion of hypoxic red blood cells (HRBCs) to transfusions with conventional RBCs. The primary efficacy objective is to demonstrate an increase in %HbA between red cell exchange transfusions (RCE) of HRBCs compared to conventional RBCs. The increases in %HbA (normal Hb) from RCE will be accompanied by a concomitant decrease in sickle Hb (%HbS). The persistence of %HbA will allow for a decrease in the volume of RBCs transfused with an overall decrease in the number of units consumed, which in turn can result in an increase in time (number of days) between transfusions.

Inclusion Criteria:

1. Male or female at least 7 years of age;
2. Are able to provide informed consent, and assent as applicable, to participate in the study;
3. Diagnosis of Sickle Cell Anemia (SCA) (HbSS, HbSβ0 thalassemia) with participation in a chronic transfusion program and have undergone regular transfusions during at least 6 months prior to Screening;
4. Have had an average interval of at least 14 days between RBC transfusions over the past 6 months;
5. If on iron chelation therapy, have been on a stable dose for ≥3 months prior to screening;

Exclusion Criteria:

1. Are not exclusively transfused at the site;
2. Have a diagnosis of HbSC disease, HbSβ+ thalassemia or another SCD variant (excluding HbSS and HbSβ0 thalassemia)
3. Are routinely transfused with washed, packed RBC units;
4. Have received hemoglobin inducers (e.g. erythropoietin) in the 30 days prior to Screening;
5. Are currently being evaluated for gene therapy;
6. Have any clinically significant pulmonary, cardiovascular, endocrine, hepatic, gastrointestinal, renal, infectious, immunological (including significant allo- or auto-immunization) disease, considered not adequately controlled prior to the study;
7. Are a female of child-bearing potential who is pregnant or planning to become pregnant in the next 14 months;
8. Have a history of allo-immunization that cannot be managed by the local blood bank;
9. Patients who, in the opinion of the Investigator, would not be able or willing to comply with the protocol;
10. Is a ward of the state, prisoner, or transient