Bone Marrow Transplantation https://doi.org/10.1038/s41409-020-0812-x CORRESPONDENCE Treatment-related mortality following autologous hematopoietic stem cell transplantation is unaffected by timing of G-CSF administration Naveed Ali 1 ● Brenda Cooper 1 ● Benjamin Tomlinson 1 ● Leland Metheny 1 ● Paolo Caimi 1 ● Kirsten Boughan 1 ● Molly Gallogly 1 ● Folashade Otegbeye 1 ● Ehsan Malek 1 ● Hillard Lazarus 1 ● Richard Creger 1 ● Marcos de Lima 1 Received: 27 July 2019 / Revised: 17 November 2019 / Accepted: 22 January 2020 © Springer Nature Limited 2020 To the Editor: High-dose chemotherapy followed by autologous hemato- poietic stem cell transplant (ASCT) is a standard consolida- tion therapy for multiple myeloma and lymphoma. Prolonged neutropenia and serious infections can be associated with significant morbidity and mortality in these patients. Granulocyte-colony stimulating factors (G-CSFs) have clinically demonstrated to accelerate neutrophil engraftment after ASCT by up to 7 days [1–3]. The American Society of Clinical Oncology (ASCO) recommends starting G-CSF 1–3 days after high-dose chemotherapy and ASCT, and continuing until the absolute neutrophil count (ANC) is ≥2000–3000 × 10 6 /L [4]. Despite evidence to support the use of G-CSF to expedite neutrophil recovery, lack of consensus with respect to optimal timing of G-CSF initiation exists in the transplant community and varies among different prac- tices. Recently, there has been a growing body of interest in late (≥day +5) G-CSF initiation after ASCT primarily for cost-effectiveness but also because growth factor-responsive neutrophilic precursors are not yet formed immediately after stem cell infusion [5]. Studies compared early (day 0 to day +4) with late (≥day +5) G-CSF initiation after ASCT with mixed results regarding neutrophil engraftment, platelet recovery or number of febrile days [6–10]. Furthermore, individualized or ANC-driven G-CSF administration did not affect outcome [11, 12]. Lastly, the usefulness of G-CSF in patients who receive >5 × 10 6 CD34+ cells/kg is also unclear. A clinical practice change was adopted at our institution in November 2016, where all patients undergoing ASCT initiated G-CSF on day +5 (late G-CSF initiation cohort), whereas those prior to November 2016 initiated on the day of transplantation (early G-CSF initiation cohort). The primary objective of this retrospective study was to compare time to neutrophil engraftment between these two cohorts. Second- ary objectives included infectious complications, length of hospital stay, treatment-related mortality, and G-CSF cost difference. The study was approved by Institutional Review Board (IRB). All consecutive patients aged ≥18 years with plasma cell neoplasm and lymphoma, who underwent ASCT from January 2015 to June 2018, were evaluated. Patients received high-dose chemotherapy and peripherally mobilized stem cells inpatient. Both cohorts received filgrastim (Neu- pogen, Amgen) at a dose of 5μg/kg/day (rounded off to the nearest vial strength; 300 μg or 480 μg). Patients weighing > 100 kg received filgrastim at a dose of 600 μg/day. Filgrastim was continued until ANC was ≥ 1000 × 10 6 /L for at least 24 hours. Supportive measures including anti-infective pro- phylaxis and transfusion of blood products were in accor- dance with institutional standardized operating procedures and did not change during the study period. A total of 178 patients were included. There were 97 (54%) patients in the early and 81 (46%) in the late G-CSF initiation cohorts. Demographic and disease-specific char- acteristics are depicted in Table 1. Both cohorts were matched with respect to age, sex, diagnosis, stem cell mobilization method, plerixafor administration, conditioning regimen, and disease status prior to stem cell transplantation (Table 1). Median infused CD34+ cell dose was higher in the late G-CSF cohort (4.259 × 10 6 /kg vs. 3.808 × 10 6 /kg, p = 0.047). Median time to neutrophil engraftment was significantly shorter in early G-CSF initiation cohort (10 [6–13] days vs. * Marcos de Lima Marcos.delima@uhhospitals.org 1 Stem cell Transplant Program, University Hospitals of Cleveland Seidman Cancer Center, Case Western Reserve University, Cleveland, OH, USA 1234567890();,: 1234567890();,: