A Pilot Study of Pre-transplant Immunosuppressive Therapy for Haploidentical Transplants in Patients With Sickle Cell Disease
This is a study to evaluate the safety and toxicity of a treatment regimen consisting of 2 cycles of pre-transplant immunosuppressive therapy followed by myeloablative preparative regimen and allogeneic hematopoietic stem cell transplantation from a haploidentical donor in patients with sickle cell disease. The overall goal of this study is to expand the donor pool for hematopoietic stem cell transplantation in sickle cell disease using haploidentical donors, and to develop a non-toxic, myeloablative regimen, with the goal of achieving a consistent donor chimerism utilizing pre-transplant immunosuppressive therapy.
• Diagnosis: Patients with sickle cell anemia (Hgb SS or SB° Thalassemia) with baseline Hgb S more than 60%.
• Disease status:
• Significant neurologic event (stroke) or any neurological deficit lasting \> 24 hours; or increased transcranial Doppler velocity (\>200 m/s).
• History of one or more episodes of acute chest syndrome (ACS) in the 2-year period preceding enrollment despite the institution of supportive care measures (i.e. asthma therapy and/or hydroxyurea).
• History of one or more severe vaso-occlusive pain crises per year in the 2-year period preceding enrollment despite the institution of supportive care measures (i.e. a pain management plan and/or treatment with hydroxyurea).
• Recurrent priapism requiring medical therapy.
• Osteonecrosis of two or more joints despite the institution of supportive care measures.
• Prior treatment with regular RBC transfusion therapy, defined as receiving 8 or more transfusions per year for \> 1 year to prevent vaso-occlusive clinical complications (i.e. pain, stroke, and acute chest syndrome)
• Echocardiograph finding of tricuspid valve regurgitation jet (TRJ) velocity ≥ 2.5 m/sec.
• Ages 1 to 30.
• Child Bearing Potential- Transplantation could be teratogenic and/or lethal to the developing fetus. For this reason, women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control or abstinence) prior to study entry and for six months following duration of study participation. Should a woman become pregnant or suspect that she is pregnant while participating on the trial, she should inform her treating physician immediately.
• Informed Consent/Assent: All subjects must have the ability to understand and the willingness to sign a written informed consent.
• The recipient must have a related donor who is genotypically haploidentical on HLA-A, B, C and DRB1 loci.
• No HLA matched sibling or 10/10 matched unrelated donor is available.