Measurement of anti-erythropoiesis-stimulating agent IgG4 antibody as an indicator of antibody-mediated pure red cell aplasia.

Patients treated with erythropoietin-based erythropoiesis-stimulating agents (ESAs) can develop a rare but life-threatening condition called antibody-mediated pure red cell aplasia (amPRCA). The antibody characteristics in a nephrology patient with amPRCA include high antibody concentrations with neutralizing activity and a mixed IgG subclass including anti-ESA IgG4 antibodies. In contrast, anti-ESA IgG4 antibody is generally not detected in baseline samples and antibody-positive non-PRCA patients.

Development and characterization of a human antibody reference panel against erythropoietin suitable for the standardization of ESA immunogenicity testing.

Recombinant human erythropoietin (EPO) has been used therapeutically for more than two decades in the treatment of anemia. Although EPO is generally well tolerated, in rare cases, patients have developed anti-EPO antibodies that can negatively impact safety and efficacy. Therefore, the detection of antibodies against EPO is a regulatory requirement during clinical development and post-approval.

Detection of anti-ESA antibodies in human samples from PRCA and non-PRCA patients: an immunoassay platform comparison.

Background: The immunological methods for detecting antibodies to erythropoiesis-stimulating agents (ESAs) differ in assay sensitivity. However, this parameter, routinely determined in clinical assays using a high-affinity non-human polyclonal antibody, gives a one-dimensional assessment of antibody detection. We compare three widely used immunological methods and evaluate the ability of each to detect mature human antibodies and human antibodies characteristic of an early immune response.

Considerations for optimization and validation of an in vitro PBMC derived T cell assay for immunogenicity prediction of biotherapeutics.

An immune response to a biotherapeutic can be induced when the therapeutic is processed and presented by antigen presenting cell to T helper cells. This study evaluates the performance of an in vitro assay that can elicit antigen specific effector T cell responses. Two biotherapeutics with known clinical immunogenicity [FPX1 and FPX2] were assessed for their ability to induce antigen-specific IFN-γ secreting T cells in peripheral blood mononuclear cells (PBMC).