A Study of Patients Treated With Erythropoietin Receptor Agonists for Anemia Who Developed Anti-erythropoietin Antibodies

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to assess the presence of anti erythropoietin antibodies (anti EPO Ab) in participants responding to any erythropoietin receptor agonist (ERA) therapy to treat or prevent anemia without loss of effectiveness to see if they will develop pure red cell aplasia or loss of effectiveness to recombinant erythropoietin and to measure the duration of effectiveness of ERA therapy.

Detailed Description
-----------------
This is an observational (study in which the investigators/physicians observe the participant's data and measure their outcomes), international, multicenter (study conducted at multiple sites), cohort (group of individuals with similar characteristics) study. The study consists of prestudy phase, observational phase (2 years), and follow-up phase (1 year). Approximately 50 participants who already receiving ERA therapy for anemia will be observed in this study. In the observational phase, participants' erythropoietin antibody status (positive or negative), clinical progress, treatment for anemia or prevention of anemia, and outcome will be monitored. During this study, enrolled participants will continue to receive standard-of-care treatment for their disease from their individual investigators as before enrollment to this study. Safety evaluations will include assessment of adverse events which will be monitored throughout the study. The total duration of the study will be 3 years.

Official Title
-----------------
An Observational Study of Subjects Treated With Erythropoietin Receptor Agonists for Anemia Who Developed Anti-erythropoietin Antibodies

Conditions
-----------------
Anemia

Intervention / Treatment
-----------------
* Drug: No intervention


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Receiving any ERA therapy for any cause of anemia and having responded to the ERA therapy for at least 3 months Positive or borderline serum for antibodies to erythropoietin identified by serum radioimmunoprecipitation Maintained a stable hemoglobin within a 3-month period that has not decreased more than 2 g/dL in any 1-month period and with no increase in red blood cell transfusion requirement An ERA maintenance dose that has not increased more than 50 percentages from initial effective dose If blood count information is available, must have a count of reticulocytes (immature red blood cells) greater than or equal to 30 million/L Exclusion Criteria: Stem cell or bone marrow transplantation Treatment with medication that decreases the ability of the immune system to function normally, within the last 3 months Participants who have shown a loss of effectiveness to ERA therapy, defined as participants who initially responded to treatment for anemia [a rise in hemoglobin which lasted for a minimum of 3 months] followed by an unexplained decrease in hemoglobin (greater than or equal to 2 g/dL) within a 1-month period
Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Erythropoietin receptor agonist<br>Participants with borderline serum anti erythropoietin (EPO) antibody (Ab) titers and who are treated with any erythropoietin receptor agonist (ERA) for any indication, having anti-EPO Ab identified by radioimmunoprecipitation (RIP), who are responding to ERA therapy, will be included in the study. | Drug: No intervention<br>* This is an observational study. All participants will be maintained on their regular dose regimen of standard-of-care treatment, under the guidance of the treating physician/investigator.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Presence of Anti-Erythropoietin Antibodies (anti-EPO Ab) | An antibody is a large Y-shaped protein secreted into the blood and is used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. Presence of anti-EPO Ab will help to find out participant's progress to the outcomes loss of effectiveness, suspected pure red cell aplasia, or confirmed pure red cell aplasia. | Up to 2 years | 
| Duration of Effectiveness of Erythropoietin Receptor Agonist Therapy |  | Up to 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Concentration of Plasma Anti Erythropoietin Antibody |  | Up to 2 years | 
| Factors That Forecast Progression to Loss of Effectiveness |  | Up to 2 years | 
| Factors That Forecast Progression to Suspected Pure Red Cell Aplasia |  | Up to 2 years | 
| Factors That Forecast Progression to Confirmed Pure Red Cell Aplasia |  | Up to 2 years | 
| Number of Participants With Adverse Events |  | Up to 3 years | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Anemia, Erythropoietin, Epoetin alfa, Erythropoietin receptor agonist (ERA) therapy, Anti-erythropoietin antibodies (anti-EPO Ab), Recombinant human erythropoietin, Pure red cell aplasia, Darbepoetin