A Novel TBI Free Conditioning Protocol for Haploidentical Transplant in Acquired Aplastic Anemia: (FluCAB-Prime)

• Published in: Blood 2020-11, Vol.136 (Supplement 1), p.12-13
• Main Authors: Iftikhar, Raheel, Chaudhry, Qamar Un Nisa, Mahmood, Syed Kamran, Ghafoor, Tariq, Shahbaz, Nighat, Khan, Mehreen Ali, Khattak, Tariq, Shamshad, Ghassan, Rehman, Jahanzeb, Farhan, Muhammad, Satti, Tariq Mahmood, Ahmed, Parvez
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2020-142753

Introduction Allogeneic hematopoietic stem cell transplant (HSCT) is the standard treatment for patients younger than 40 years with Severe and Very Severe Aplastic Anemia (AA) who have a Matched Related Donor (MRD). For patients lacking a MRD, treatment options include immunosuppressive therapy (IST), matched unrelated donor (MUD) or alternate donor (haploidentical/cord blood) transplant. Pakistan has a population of around 23 million but there is no donor registry for MUD transplants and horse antithyomcyte globulin (hATG) is not available. Over past decade, results of haploidentical transplants have improved remarkably with use of post-transplant cyclophosphamide. However, most of these protocols incorporate total body irradiation (TBI) to improve engraftment and reduce graft failure. TBI is not available in most of the transplant centres across Pakistan. We have developed a novel TBI free conditioning regimen (NCT03955601) for haploidentical HSCT in acquired AA patients lacking a MRD. Materials and Methods We conducted a prospective, single centre, interventional trial (NCT03955601) using novel TBI free conditioning at AF bone marrow transplant centre (AFBMTC)/ National institute of blood and marrow transplant (NIBMT) for patients with acquired severe and very severe AA. Between July 2018 and March 2020, a total of 10 patients received related haploidentical transplant.Study inclusion criteria was diagnosis of severe and very severe AA, patients of both genders, age 2-60 years, Karnofsky performance status>70%. Exclusion criteria was presence of donor specific antibodies (DSA), inherited bone marrow failure syndrome, prior HSCT and severe sepsis. Conditioning regimen used was Fludarabine (Flu) 30 mg/m2 IV daily from day -7 to -3, Cyclophosphamide (Cy) 14.5 mg/kg IV daily on day -6 and -5 , rabbit Antithymocyte globulin (rATG) 5 mg /kg/day from day -6 to day-3; Busulphan (Bu) IV 3.2 mg per kg/day in 04 divided doses on day -3 and day-2, Granulocyte Colony Stimulating factor (GCSF) primed Bone marrow harvest (BMH) and/or PBSC graft on day 0 and day +1 respectively. Graft versus host disease (GVHD) prophylaxis used was post-transplant cyclophosphamide (PTCy) administered at a dose of 50mg/kg/day given daily on days +3 and +5 post-transplant, cyclosporine (CsA) from day +5 and mycophenolate mofetil (MMF) from day+5 to +35. Primary outcome measure was overall survival (OS) while secondary outcome measures included graft failure, treatment related mortality (