Clinical Factors Influencing Engraftment In Patients With Non-Hodgkin Lymphoma Following Autologous Stem Cell Transplant.

e19504 Background: Autologous Stem Cell Transplant (ASCT) is considered as standard of care for patients (pts) with relapsed and refractory non-Hodgkin's lymphoma (NHL). In this study we evaluated delayed engraftment (DE) in large cohort of ASCT recipients with NHL. Methods: 1,162 pts undergoing ASCT at a single institution from 1996-2016 were retrospectively reviewed to determine DE, defined as platelet count ≤50,000/μl, hemoglobin ≤8 g/dL, or ANC ≤1000 mm3. Pts with prior ASCT or those lost to follow up were excluded. Results: NHL represented only 209/1162 (18.0%) of pts undergoing ASCT but accounted for 108/239 (45.2%) of pts with DE at 30 days (Table 1). By comparison, multiple myeloma (MM) represented 686/1162 (59.0%) of pts undergoing ASCT but accounted for only 69/239 (28.9%) of pts with DE at 30 days. This was statistically significant (p = 0.05, OR = 2.377 (95% CI 1.00, 5.65). Given this discrepancy for the engraftment of NHL pts, the 108 NHL pts with DE were analyzed further to determine clinical factors influencing development of DE in NHL pts. In univariate analysis NHL type (p = 0.99), stage (p = 0.95), disease status at transplant (p = 0.54), bone marrow or extranodular involvement (p = 0.54, 0.68), conditioning regimen (p = 0.39), EBV and CMV viral serologies (p = 0.51, 0.06), history of radiation therapy (p = 1.0), prior chemotherapy regimens, and CD34+ dose (p = 0.11) showed no statistically significant impact on development of DE in NHL pts. Conclusions: DE was identified in 52% of all pts with NHL and pts with NHL have a significantly higher risk for the development of DE as compared to MM pts. Disease stage, bone marrow or extranodular involvement, chemotherapy regimen, or other treatment related factors had no influence of DE indicating that this inherent characteristic of NHL and its impact of marrow microenvironment can be responsible for this discrepancy in DE Table 1: Demographics of NHL pts with DE Variable n = 108 (%) Stage 1 (1%) 2(14%) 3(17%) 4(69%) NHL subtype - DLBCL 57 (53%) Mantle cell 18 (17%) Follicular 11 (10%) T-cell 10 (9%) B-cell 6 (6%) Other 6 (6%) Disease status at transplant - CR 59 (55%) PR 49 (45%) Extranodular disease - Yes 67 (62%) No 41 (38%) Bone marrow involvement - Yes 40 (37%) No 68 (63%)