Outpatient Haploidentical Stem Cell Transplantation Using Post-Transplant Cyclophosphamide Is Safe and Feasible

Hematopoietic stem cell transplantation (HSCT) feasibility has increased in the last decades because of haplo-HSCT, changes in chemotherapy schedules, and the possibility of an outpatient-based HSCT. The main barriers remain in low-middle income countries. There is a lack of information regarding haplo-HSCT with a myeloablative (MAC) regimen on an outpatient basis.

Our primary objective was to determine if outpatient haplo-HSCT was feasible.

Single center, retrospective cohort, n=60 adult patients undergoing Haplo-HSCT. Descriptive statistical analysis, univariate and multivariate comparison.

We analyzed 60 adult patients transplanted with an intended haplo-HSCT on an outpatient basis from 2015 to 2019 in our unit. A multivariate analysis was performed on risk factors for hospitalization.

Median age was 27 years (15-64). All patients underwent conditioning as outpatients, and none required hospitalization before day 0. Thirteen patients (21.6%) were followed completely in the outpatient clinic and 47 (78.3%) required hospitalization in a median of 3 days after infusion (range, 1-14). The median length of stay (LOS) was 8 days (IQR, 3-17). Fever secondary to cytokine release syndrome (CRS) was the most common reason for hospitalization occurring in 43/47 (91.5%), 4 were related to infection and 36 were related to CRS. In the univariate analysis, CRS, slower engraftment, and female sex were associated with the need for hospitalization. In the multivariate analysis, only CRS remained significant (OR 9.14 [95%CI, 1.58-56.46]). The 2-year overall survival (OS) was 41.7% for ambulatory transplant vs. 38% for those requiring hospitalization (P = 0.12). The 2-year event-free survival (EFS) was 33% for outpatient patients and 16.7% for those hospitalized (log-rank, P = 0.062).

We demonstrated the feasibility and safety of carrying out an outpatient haplo-HSCT, potentially resulting in cost savings and perhaps a higher quality of life.