Rabbit Antithymocyte Globulin Versus Campath-1H for Treating Severe Aplastic Anemia

July 2, 2021 updated by: National Heart, Lung, and Blood Institute (NHLBI)

A Randomized Trial of Immunosuppression in Aplastic Anemia Patients With Refractory Pancytopenia or Suboptimal Hematologic Response After h-ATG/CsA Treatment

Severe aplastic anemia, characterized by pancytopenia and a hypocellular bone marrow, is effectively treated by immunosuppressive therapy, usually a combination of antithymocyte globulin (ATG) and cyclosporine (CsA). Survival rates following this regimen are equivalent to those achieved with allogeneic stem cells transplantation. However, approximately 1/3 of patients will not show blood count improvement after ATG/CsA. General experience and small pilot studies have suggested that such patients may benefit from further immunosuppression. Furthermore, analysis of our own clinical data suggest that patients with poor blood count responses to a single course of ATG, even when transfusion-independence is achieved, have a markedly worse prognosis than patients with robust hematologic improvement. The management of such cases is uncertain.

This study will enroll patients who are either refractory to h-ATG (continued severe pancytopenia) or who have only modest improvement in blood counts (weak hematologic responders) to receive a further immunosuppressive therapy, delivered either as rabbit ATG (Thymoglobulin, r-ATG) or a humanized monoclonal antibody to T-cells, alemtuzumab (Campath-1H ). Primary endpoint will be response rate at 3 months defined as no longer meeting criteria for severe aplastic anemia. Relapse, robustness of hematopoietic recovery at 3 months, survival and clonal evolution to paroxysmal nocturnal hemoglobinuria (PNH), myelodysplasia and acute leukemia will be the secondary endpoints.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Severe aplastic anemia, characterized by pancytopenia and a hypocellular bone marrow, is effectively treated by immunosuppressive therapy, usually a combination of antithymocyte globulin (ATG) and cyclosporine (CsA). Survival rates following this regimen are equivalent to those achieved with allogeneic stem cells transplantation. However, approximately 1/3 of patients will not show blood count improvement after ATG/CsA. General experience and small pilot studies have suggested that such patients may benefit from further immunosuppression. Furthermore, analysis of our own clinical data suggest that patients with poor blood count responses to a single course of ATG, even when transfusion-independence is achieved, have a markedly worse prognosis than patients with robust hematologic improvement. The management of such cases is uncertain.

This study will enroll patients who are either refractory to h-ATG (continued severe pancytopenia) or who have only modest improvement in blood counts (weak hematologic responders) to receive further immunosuppressive therapy, delivered either as rabbit ATG (Thymoglobulin , r-ATG) or a humanized monoclonal antibody to T-cells, alemtuzumab (Campath-1H ). Primary endpoint will be response rate at 6 months defined as no longer meeting criteria for severe aplastic anemia. Relapse, robustness of hematopoietic recovery at 6 months, survival and clonal evolution to paroxysmal nocturnal hemoglobinuria (PNH), myelodysplasia and acute leukemia will be the secondary endpoints.

Study Type

Interventional

Enrollment (Actual)

54

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Maryland
      • Bethesda, Maryland, United States, 20892
        • National Institutes of Health Clinical Center, 9000 Rockville Pike

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

2 years and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

  • INCLUSION CRITERIA:

Severe aplastic anemia confirmed at NIH by:

Bone marrow cellularity less than 30% (excluding lymphocytes)

At least two of the following:

Absolute neutrophil count less than 500/microL;

Platelet count less than 20,000/ microL;

Reticulocyte count less than 60,000/ microL.

Severe aplastic anemia refractory to prior course(s) of h-ATG/CsA defined after 3 months from treatment with less or equal to 4 years from receiving h-ATG.

OR

Suboptimal response to initial immunosuppression with h-ATG/CsA as defined by platelet and reticulocyte count less than 50,000 /microL at 3 months.

Age greater than or equal to 2 years of age

EXCLUSION CRITERIA:

Diagnosis of Fanconi anemia.

Evidence of a clonal disorder on cytogenetics. Patients with super severe neutropenia (ANC less than 200/microL) will not be excluded initially if results of cytogenetics are not available or pending. If evidence of a clonal disorder is later identified, the subject will go off study.

Prior treatment courses with rabbit ATG or high dose cyclophosphamide (200 mg/kg or equivalent).

Infection not adequately responding to appropriate therapy.

Underlying immunodeficiency state including seropositivity for HIV.

Failure to discontinue the herbal supplements Echinacea purpurea or Usnea barbata (Old Man's Beard) within two weeks of enrollment.

Previous hypersensitivity to Campath-1H or its components.

Moribund status or concurrent hepatic, renal, cardiac, neurologic, pulmonary, infectious, or metabolic disease of such severity that it would preclude the patient s ability to tolerate protocol therapy or that death within 7-10 days is likely.

Potential subjects with cancer who are on active chemotherapeutic treatment or who take drugs with hematological effects will not be eligible.

Serum creatinine greater than 2.5 mg/dL.

Current pregnancy or lactation or unwillingness to take contraceptives.

Inability to understand the investigational nature of the study or give informed consent.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: r-ATG /cyclosporine
A randomized trial of rabbit anti-thymocyte globulin (r-ATG)/ cyclosporine (CsA) versus Campath-1H in aplastic anemia patients with refractory pancytopenia or suboptimal hematological response after horse ATG treatment. Subjects who receive rabbit ATG/ CsA will be given rabbit ATG 3.5mg/kg/day for 5 days and CsA 10mg/kg/day orally twice daily for 6 months (15mg/kg/day for children under 12 yrs. Subjects who receive Campath-1H will receive an intravenous infusion for 10 days. Adult subjects will receive 10mg/day (children:0.2mg/kg/day).
Drug: r-ATG
Rabbit ATG 3.5mg/kg/day for consecutive 5 days
Other Names:
  • Rabbit Anti-Thymoglobulin
Drug: CsA
CsA 10mg/kg/day orally twice daily for 6 months (15mg/kg/day for children under 12 yrs.
Other Names:
  • Cyclosporine
Experimental: Alemtuzumab (Campath-1H)
A randomized trial of rabbit anti-thymocyte globulin (ATG)/ cyclosporine (CsA) versus Campath-1H in aplastic anemia patients with refractory pancytopenia or suboptimal hematological response after horse ATG treatment. Subjects who receive rabbit ATG/ CsA will be given rabbit ATG 3.5mg/kg/day for 5 days and CsA 10mg/kg/day orally twice daily for 6 months (15mg/kg/day for children under 12 yrs. Subjects who receive Campath-1H will receive an intravenous infusion for 10 days. Adult subjects will receive 10mg/day (children:0.2mg/kg/day).
Drug: Campath-1H
Campath-1H IV 10 days. Adults:10mg/day (children:0.2mg/kg/day).
Other Names:
  • Alemtuzumab

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Participants no Longer Meeting Criteria for Severe Aplastic Anemia.
Time Frame: 6 months
Number of participants no longer meeting the criteria for severe aplastic anemia as measured by response to treatment at 6 months
6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Participants With Robust Hematologic Recovery With Reticulocyte or Platelet Count
Time Frame: 6 months
Number of participants with robust hematologic recovery with reticulocyte or platelet count ≥ 50,000/uL
6 months
Percentage of Cumulative Incidence of Relapse in Participants
Time Frame: 3 year
Percentage of cumulative incidence of relapse of disease in participants
3 year
Percentage of Cumulative Incidence of Clonal Evolution in Participants
Time Frame: 3 years
Percent of cumulative incidence of clonal evolution in participants to either paroxysmal nocturnal hemoglobinuria (PNH), myelodysplasia or acute leukemia.
3 years
Percentage of Participants no Longer Meeting Criteria for Severe Aplastic Anemia.
Time Frame: 3 months and 6 months
Percentage of participants no longer meeting the criteria for severe aplastic anemia as measured by response to treatment
3 months and 6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Heart, Lung, and Blood Institute (NHLBI)

Investigators

  • Principal Investigator: Danielle M Townsley, M.D., National Heart, Lung, and Blood Institute (NHLBI)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 6, 2003

Primary Completion (Actual)

December 29, 2010

Study Completion (Actual)

February 5, 2016

Study Registration Dates

First Submitted

July 18, 2003

First Submitted That Met QC Criteria

July 18, 2003

First Posted (Estimate)

July 21, 2003

Study Record Updates

Last Update Posted (Actual)

July 21, 2021

Last Update Submitted That Met QC Criteria

July 2, 2021

Last Verified

June 1, 2021

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 030249
  • 03-H-0249

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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