Influence of Donor Type, Stem Cell Source and Conditioning Regimen on Transplant Outcomes after Haploidentical Transplant with Post Transplant Cyclophosphamide for Lymphoma: A Report of the EBMT Lymphoma Working Party

Allogeneic stem cell transplantation (SCT) is potentially curative for patients with lymphoma who progress after autologous SCT. For patients with no HLA identical donor, haploidentical transplant is becoming the major source of alternative donors, particularly with the use of post transplant cyclophosphamide (ptCy). However, there are little data on whether outcomes are affected by the characteristics of the haploidentical donor, the stem cell source or the conditioning. To address this important subject, we identified 474 adult patients (35% females; median age 41 years; range 18-72) with Hodgkin lymphoma (HL-240; 51%), peripheral T cell lymphoma (PTCL-88; 19%), diffuse large B cell lymphoma (DLBCL-77; 16%), mantle cell lymphoma (MCL-40; 8%) or follicular lymphoma (FL-29; 6%), who received a haploidentical SCT (haploSCT) with ptCy between 2010 and 2016 at EBMT participating centers. Patients, donors and transplant characteristics are summarized in Table 1. Median follow-up of alive patients was 32 months (range 3-93). Engraftment by day 100 was successful in 95% of patients. In multivariate Cox analysis (MVA), the use of peripheral blood stem cells (PBSC) positively affected engraftment (HR=1.53; p In conclusion, this is the largest study on the influence of donor characteristics, stem cell source and conditioning in haploSCT with ptCy for lymphoma. These results provide critical information to help selecting the best donor in the setting of haploSCT for lymphoma. Our results indicate that the use of PBSC significantly improves engraftment but increases the risk of acute GVHD. Conditioning only influenced NRM but had no effect on PFS or OS. The use of female donors increases the risk of chronic GVHD. Of note, PFS and OS are mostly influenced by disease characteristics (i.e disease status and lymphoma subtype), whereas, with the exception of CMV compatibility, no other donor characteristics (donor age and gender, relationship of the donor to the recipient, degree of HLA mismatch or ABO incompatibility, prior donor pregnancy) impact on PFS or OS, supporting the use of any haplo-identical family member as a donor. Disclosures Tischer:Jazz Pharmaceuticals: Other: Jazz Advisory Board. Mohty:MaaT Pharma: Consultancy, Honoraria. Chalandon:Roche: Membership on an entity9s Board of Directors or advisory committees, Other: Travel costs. Sureda:BMS: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Sanofi: Honoraria; Merck: Consultancy, Honoraria; Roche: Honoraria.