alemtuzumab + sirolimus

Alemtuzumab + sirolimus (the SUN regimen) is a nonmyeloablative conditioning protocol used for HLA-identical sibling donor hematopoietic stem cell transplantation in patients with sickle cell disease. Developed by Robert Nickel and the Sickle Cell Transplant Advocacy and Research Alliance (STAR), the regimen combines alemtuzumab, a humanized monoclonal antibody targeting CD52 for lymphocyte depletion, with low-dose total body irradiation (300 cGy) and sirolimus, an mTOR inhibitor used for post-transplant immunosuppression. This chemotherapy-free approach is designed to achieve stable donor chimerism and reverse the sickle cell phenotype while minimizing the severe toxicities, such as infertility and organ damage, associated with traditional myeloablative conditioning.

Other names

Sickle transplant Using a Nonmyeloablative approach