ASCO clinical guidelines recommends administration of WBC growth factors after autologous stem cell transplant (ASCT) to reduce the duration of severe neutropenia (Smith TJ et al., Recommendations for the use of WBC growth factors: American society of clinical oncology clinical practice guideline update. J Clin Oncol, 33(28):3199-3212, 2015). But there is conflicting data regarding the optimal timing of granulocyte colony stimulating factor (G-CSF) initiation post-transplantation and a lack of recent cost effectiveness analysis. Based on single center studies showing similar results between an early approach and a delayed one, we changed our institutional standard to a delayed strategy since June 2020.
We retrospectively compared the outcomes of adult multiple myeloma ASCT patients who received G-CSF either on day 2 (early) or day 5 (late) at Roger Williams Medical Center. Sixteen consecutive patients received day 2 G-CSF between July 2018 and June 2020 (D+2 cohort) while seven received day 5 since implementing the change in June 2020 (D+5 cohort). The doses of G-CSF given were 300 mcg, 480 mcg, 600 mcg or 960 mcg. One-way factorial ANOVA and Fit Y by X was used for comparison of variables. Descriptive statistics were used where appropriate.
Baseline characteristics were comparable between the D+2 and D+5 cohorts (median age 62 vs 63 years, median CD34+cells 4.01 vs 4.54 x10 6/kg respectively). The median number of prior treatments, conditioning intensity, disease status at transplant and G-CSF doses were similar in both cohorts. Median ANC at G-CSF initiation was different (3300 in D+2 vs 100 in D+5). The median follow-up for survivors was 215 days for D+5 cohort (range: 135-404 days) and 699 days for D+2 cohort (range: 418-923 days). The results are summarized in table 1. For the primary outcome, median time to neutrophil engraftment was 13 days versus 10 days in the early and late cohorts, respectively (p=0.07). Median days from administration of GCSF to hospital discharge was noted to be shorter in the late cohort (13 vs 17.5 days, p=0.05). There was no statistically significant difference in the incidence of febrile neutropenia or transfusion requirements with late initiation of G-CSF. While engraftment syndrome and duration of antibiotics were noted to be more in the early cohort, these were not statistically significant. Median length of hospital stay was a day and half shorter in the late cohort. 6-month OS favored the D+5 cohort (p=0.03); this was likely due to transplant related deaths in early cohort. The average cost saving per patient by implementing the late strategy was 887.4 $.
Late initiation of G-CSF following autologous ASCT in patients with multiple myeloma was associated with a shorter time to neutrophil engraftment and length of stay post transplantation with no difference in overall outcomes. Cost benefit analysis favors delaying initiation of GCSF for autologous SCT at our center.
No relevant conflicts of interest to declare.