Assessing and mitigating the interference of ALX148, a novel CD47 blocking agent, in pretransfusion compatibility...

Area of Science:

• Transfusion Medicine
• Immunology
• Oncology

Background:

• ALX148 is a CD47 blocking agent for advanced solid tumors and lymphoma.
• CD47 on red blood cells (RBCs) can be affected by therapeutic blockade.
• This interference impacts pretransfusion compatibility testing.

Purpose of the Study:

• To describe ALX148 interference in pretransfusion compatibility testing.
• To evaluate methods for mitigating this interference.

Main Methods:

• Serologic tests on patient samples treated with ALX148.
• Antibody screening and RBC antigen typing.
• Use of soluble CD47 or SIRPα monomers to remove false-positive reactivity.

Main Results:

• ALX148 caused false-positive reactivity in indirect antiglobulin testing (IAT) and papain testing.
• No false positives were observed in immediate spin, room temperature, or 37°C phases.
• Soluble CD47 or SIRPα monomers successfully removed false positives without affecting clinically significant antibody detection.

Conclusions:

• ALX148 interference in IAT requires mitigation strategies.
• Soluble CD47 or SIRPα monomers effectively resolve interference in pretransfusion compatibility testing.