Improving Immunosuppressive Treatment for Patients With Severe Aplastic Anemia

Sponsor

National Heart, Lung, and Blood Institute (NHLBI) (NIH)

Overall Status

Completed

CT.gov ID

NCT00061360

Collaborator

(none)

Enrollment

Location

Arms

146.4

Actual Duration (Months)

0.5

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Severe aplastic anemia (SAA) is a life-threatening bone marrow failure disorder characterized by pancytopenia and a hypocellular bone marrow. Allogeneic bone marrow transplantation and immunosuppressive treatment with anti-thymocyte globulin (ATG) and cyclosporine (CsA) have dramatically changed the natural course of this illness, with 5 year survival of 75% in patients undergoing either treatment. Since most patients are not suitable candidates for hematopoietic stem cell transplantation (HSCT) due to advanced age or lack of a histocompatible sibling, efforts at NHLBI have focused on improving immunosuppression treatment in order to improve response rates, survival, and to decrease relapse.

In our experience of 122 patients treated at NHLBI with the combination of ATG and cyclosporine, one quarter to one third did not respond; about 50% of responders relapsed; and 5 year survival was correlated with the robustness in blood cell count improvement at 3 months (reticulocyte or platelet count greater than or equal to 50,000 /uL). Why some patients do not respond initially while others relapse is unclear. Autoreactive T cells may be resistant to the effect of ATG/CsA (nonresponders), while in others residual autoreactive T cells expand post-treatment leading to hematopoietic stem cell destruction and recurrent pancytopenia (relapse). Therefore, novel immunosuppressive regimens to increase response rates and hematologic recovery at 3 months and to decrease relapse rates are needed. An ongoing NHLBI trial, which is close to completing accrual, has added mycophenolate mofetil (MMF) for a total of 18 months to standard ATG + CsA in an attempt to reduce the relapse rate after cyclosporine is discontinued. Preliminary results have been disappointing, with no marked reduction in relapse among patients who received MMF.

Sirolimus (rapamycin, Rapamune , RAPA) is a novel immunosuppressive agent, which acts synergistically with cyclosporine by blocking T cell activation through CsA-resistant pathways. The potentiation of the combination of CsA-RAPA has been established in vitro and in the clinical setting, mainly in islet cell and solid organ transplantation. The significant increase in response rate seen with the addition of CsA to ATG indicated that an inhibitory effect on T lymphocytes is important in blocking autoreactive T cells in aplastic anemia. The combination of CsA-RAPA may further block activated autoreactive T cells and therefore lead to improved response rates (and survival) and decreased relapse rates.

This prospective randomized phase II study will investigate two different immunosuppressive regimens in patients with severe aplastic anemia who have not received prior immunosuppressive therapy. One arm will receive ATG + CsA in addition to sirolimus for 6 months, and the second arm will receive standard ATG + CsA for 6 months followed by a slow taper of CsA with a 25% dose reduction every 3 months for the subsequent 18 months. This trial will determine the effectiveness of sirolimus in patients with aplastic anemia as well as the role of a cyclosporine taper in preventing relapses. Primary endpoint will be no longer meeting criteria for severe aplastic anemia while secondary endpoints are relapse, robustness of hematologic recovery at 3 months, survival, clonal evolution to PNH, myelodysplasia and acute leukemia.

10/11/2005. The Sirolimus (Rapamune) arm of the trial was stopped for lack of efficacy. The study will continue as a single arm study to establish if slow taper of CsA prevents relapse rates after initial standard treatment with ATG followed by CsA for six months.

Condition or Disease	Intervention/Treatment	Phase
Severe Aplastic Anemia	Drug: ATG+Rapamune+cyclosporine Drug: ATG+cyclosporine	Phase 2

Detailed Description

3/2/2006. The protocol was closed to new accrual.

Study Design

Study Type:

Interventional

Actual Enrollment :

77 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

None (Open Label)

Primary Purpose:

Treatment

Official Title:

A Randomized Trial of a Novel Immunosuppressive Combination of ATG, CsA and Sirolimus (Rapamune) vs a Slow Taper Cyclosporine Regimen in Subjects With Severe Aplastic Anemia

Actual Study Start Date :

Jun 26, 2003

Actual Primary Completion Date :

Feb 15, 2006

Actual Study Completion Date :

Sep 8, 2015

Arms and Interventions

Arm	Intervention/Treatment
Experimental: ATG+CsA ATG+CsA for 6 months followed by a slow CsA taper in the subsequent 18 months	Drug: ATG+cyclosporine ATG+cyclosporine
Experimental: ATG+CsA+RA ATG+CsA+RAPA for 6 months	Drug: ATG+Rapamune+cyclosporine ATG+Rapamune+cyclosporine

Arm

Intervention/Treatment

Experimental: ATG+CsA

ATG+CsA for 6 months followed by a slow CsA taper in the subsequent 18 months

Drug: ATG+cyclosporine

ATG+cyclosporine

Experimental: ATG+CsA+RA

ATG+CsA+RAPA for 6 months

Drug: ATG+Rapamune+cyclosporine

ATG+Rapamune+cyclosporine

Outcome Measures

Primary Outcome Measures

Hematologic recovery in patients with severe aplastic anemia treated with a novel immunosuppressive combination of ATG, CsA and sirolimus. [2 yrs]
Up to 10/11/2005- Response rate at 3 months defined as no longer meeting criteria for SAAFrom 10/11/2005-relapse rates after initial standard treatment with ATG followed by CsA for six months

Secondary Outcome Measures

6-month response rate [6 months]
Robustness of hematologic recovery with reticulocyte count or platelet count 50,000/uL at 3 months [3 months]
Relapse [Ongoing]
Clonal evolution to MDS, PNH or acute leukemia [Ongoing]
Survival [Ongoing]

Eligibility Criteria

Criteria

Ages Eligible for Study:

2 Years to 110 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

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/ uL; Platelet count less than 20,000/ uL; Absolute reticulocyte count less than 60,000/ uL

Age greater than or equal to 2 years old

Weight greater than 12 kg

EXCLUSION CRITERIA:

Serum creatinine greater than 2.5 mg/dL

Underlying carcinoma (except local cervical, basal cell, squamous cell)

Prior immunosuppressive therapy with ATG, ALG, or high dose cyclophospamide.

Current pregnancy or lactation or unwillingness to take oral contraceptives or use an effective method of birth control.

Diagnosis of Fanconi anemia or other congenital bone marrow failure syndromes

Evidence of a clonal disorder on cytogenetics. Patients with super severe neutropenia (ANC less than 200/uL) will not be excluded if results of cytogenetics are not available or pending.

Underlying immunodeficiency state including seropositivity for HIV

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

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.