This is a prospective pilot study with primary aim of determining whether investigational FLT imaging can detect and distinguish nonengraftment from delayed engraftment after HSCT in populations at highest risk for graft failure. The investigator will enroll up to 56 patients to achieve 50 evaluable patients undergoing hematopoietic cell transplantation on this trial \[5 pediatric and adult recipients of cord blood stem cells (Arm A1), 15 pediatric and adult recipients of myeloablative haplo-identical HSCT (Arm A2), 10 pediatric and adult recipients of reduced intensity haplo-identical HSCT (Arm A3), and 20 recipients of these two stem cell sources who have not engrafted by day 28 (Arm B)\]. Should a patient be unable to undergo FLT evaluation after enrollment or relapse in the first 30 days, the patient will be replaced. The planned length of this trial is 7 years and it will be conducted at 4 centers enrolling participants: Emory/Children's Healthcare of Atlanta, University of Oklahoma, University of Michigan, and University Hospitals of Cleveland.
For all pediatric and adult patients undergoing cord blood HSCT, FLT imaging will occur one day prior to HSCT and on days 9 and 28 after HSCT (Arm A1). For recipients of haplo-HSCT, FLT PET/CT imaging will occur one day prior to HSCT and on days 5 or 9 and 28 after HSCT (Arm A2 and A3). Pediatric and adult patients who have not engrafted by day 20 after cord or haplo-identical HSCT will undergo a single FLT image within one week to determine if this scan can identify graft failure versus delayed engraftment (Arm B). All patients will undergo serial peripheral blood evaluation for blood biomarker analysis, including thymidine kinase-1 (TK1). Study endpoints include: 1) detection of nonengraftment with FLT and TK1, 2) development of a model that predicts nonengraftment versus delayed engraftment using FLT and TK1, 3) sensitivity of individual biomarkers to distinguish between graft failure and delayed engraftment, and 4) biology of cord blood and haplo-HSCT engraftment.
For all pediatric and adult patients undergoing cord blood HSCT, three FLT images will be taken: first, one day prior to HSCT and second and third, on days 9 and 28 after HSCT. For recipients of haplo-HSCT, the FLT images will be taken one day prior to HSCT and then on days 5 and 28 after HSCT. Pediatric and adult patients who have not engrafted by day 24 after cord or haplo-identical HSCT will undergo a single FLT PET/CT image within one week, to determine if this scan can identify graft failure versus delayed engraftment. Blood samples will also be collected from all patients for blood biomarker analysis, including thymidine kinase-1 (TK1). Each patient will be in this study for one year.
