1077. Infectious complications after second allogeneic hematopoietic cell transplant (allo-HCT) in adult patients with hematological malignancies

Background A 2nd allo-HCT is received by some adults after relapse of their underlying malignancy, development of a second malignancy, or graft failure. Few studies have reported on infectious complications in adults given a 2nd HCT Methods This is a retrospective review of infectious complications and overall mortality of 60 adult patients who received a 2nd HCT from Jan. 2010 - Dec. 2015. Data were collected for 2 years post-HCT for each patient. Infections were separated into < 30 days (d) post-HCT, 30-100d post-HCT, and >100d post-HCT. Results Mean age at 2nd HCT was 49+13; 60% were men. The most common reason for the 1st HCT was acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) (73%,n= 44) The 2nd HCT was for relapse of original malignancy (62%,n=37), graft failure (27%,n=16), and new malignancy (10%,n=6). The 2nd HCT was received a median of 344d (range 29-8248) after 1st HCT. Neutrophil engraftment occurred by 13+4d in 50/60 patients. Fifty-eight patients (97%) had at least one infection during the study period. A total of 183 infections were reported: 75 (41%) were < 30d, 56 (31%) 30-100d, and 52 (28%) >100d post-HCT. Bacterial infections, primarily C. difficile, vancomycin-resistant Enterococcus, and coagulase (-) Staphylococcus caused 90 (49%) infections and were seen throughout the post-HCT period. Viral infections, predominantly CMV and BK virus, caused 60 (33%) of infections, peaking at 30-100d post-HCT. Only 19 (10%) infections were fungal, most of which were mold infections and occurred >30d post-HCT. Thirty-nine (65%) patients died by 2 years post-HCT, 27 within the first year. Cause of death was infection in 16 (41%), graft failure, relapse, or GVHD in 16 (41%), other in 7 (18%). At < 30d post-HCT, 5 deaths (71%) were from infection 4 of which were bacterial. At 30-100d post-HCT, 6/9 (69%) deaths were from relapse/graft failure/GVHD. All 6 deaths from fungal infections were >100d post-HCT. Bacterial Infections and engraftment failure within 100d post-HCT were associated with increased mortality (p .05 and < .001, respectively). Conclusion All but 2 patients receiving a 2nd allo-HCT developed an infection. Most deaths at < 30d post-HCT were from infection. Overall 2-year mortality was 65% and 41% of deaths were related to infection. Disclosures Marisa H. Miceli, MD, FIDSA, SCYNEXIS, Inc. (Advisor or Review Panel member)