Intensive monitoring of minimal residual disease and chimerism after allogeneic hematopoietic stem cell transplantation for acute leukemia in children.

Posttransplant leukemia detection before overt relapse is key to the success of immunotherapeutic interventions, as they are more efficient when leukemia burden is low. However, optimal schedule and monitoring methods are not well defined. We report the intensive bone marrow monitoring of minimal residual disease (MRD) using flow cytometry (FC) and nested reverse transcription polymerase chain reaction (RT-PCR) whenever a fusion transcript allowed it and chimerism by PCR at 11 timepoints in the first 2 years after transplant. Seventy-one transplants were performed in 59 consecutive children, for acute myeloid (n = 38), lymphoid (n = 31), or mixed-phenotype (n = 2) leukemia. MRD was monitored in 62 cases using FC (n = 58) and/or RT-PCR (n = 35). Sixty-seven percent of leukemia recurrences were detected before overt relapse, with a detection rate of 89% by RT-PCR and 40% by FC alone. Increased mixed chimerism was never the first evidence of recurrence. Two patients monitored by RT-PCR relapsed without previous MRD detection, one after missed scheduled evaluation and the other 4.7 years post transplant. Among the 22 cases with MRD detection without overt relapse, 19 received therapeutic interventions. Eight (42%) never relapsed. In conclusion, intensive marrow monitoring by RT-PCR effectively allows for early detection of posttransplant leukemia recurrence.

Intrabone infusion for allogeneic umbilical cord blood transplantation in children.

Umbilical cord blood transplantation (UCBT) has been used to treat malignant and non-malignant diseases. UCBT offers the advantages of easy procurement and acceptable partial HLA mismatches, but also shows delayed hematopoietic and immunological recoveries. We postulated that an intrabone (IB) infusion of cord blood could provide a faster short- and long-term engraftment in a pediatric population with malignant and non-malignant hematologic diseases. We conducted this phase I-II single arm, exploratory clinical trial (NCT01711788) from 2012 to 2016 in a single center. Fifteen patients aged from 1.9 to 16.4 years received an IB UCBT. Median time to neutrophils and platelet recoveries were 18 days (range: 13-36 days) and 42 days (range: 26-107 days), respectively. Rate of severe acute GVH grade was low, with only one patient with grade III aGVH. Relapse occurred in 5 patients (38.5%) and TRM occurred in 1 patient. This leads to 6 years EFS and OS of 66.7% and 80% respectively. In conclusion, IB UCBT is safe and well-tolerated in children and hematological recovery compared similarly to the results obtained with IV UCBT.

Decision-Making in the Era of New Medical Technologies in Pediatric Hematology-Oncology: The Death of Palliative Care?

BACKGROUND: Recent advances in immunology, genomics, and cellular therapy have opened numerous therapeutic possibilities in pediatric hematology-oncology, generating new hope in poor prognosis situations. How decisions are made when it comes to treatments and aims needs to be explored in this new technologic context. In particular, their impact on the gold standard of early referral to palliative care must be assessed. MATERIALS AND METHODS: Stemming from an ethnographic study combining semistructured interviews and observations carried out in a hematopoietic stem cell transplant unit in a Montréal Pediatric Hospital, we discuss the decision-making process when a patient faces poor prognosis. RESULTS AND DISCUSSION: Although health care providers individually envisioned that palliative care may be the best course of action for patients receiving emergent therapy, they remained collectively in the curative mode. The intricate relationship between science, hope, caregiver, and care receiver sustains this perspective even when (near) death is the probable outcome. When proven treatment fails, emerging therapeutic possibilities offer new hope that can delay the referral to the palliative care team.