Cryopreservation of Allogeneic Hematopoietic Cell Products During COVID-19 Pandemic: Graft Characterization and Engraftment Outcomes.

BACKGROUND: The COVID-19 pandemic triggered the deployment of unfamiliar measures to safeguard successful allogeneic hematopoietic cell transplantation (allo-HCT). Among these measures, cryopreservation offered logistical benefits that could outlast the pandemic, including graft availability and timely clinical service. The purpose of this study was to evaluate graft quality and hematopoietic reconstitution in patients transplanted with cryopreserved allogeneic stem cell products during the COVID-19 pandemic. METHODS: We evaluated 44 patients who underwent allo-HCT using cryopreserved grafts consisting of hematopoietic progenitor cells (HPC) apheresis (A) and bone marrow (BM) products at Mount Sinai Hospital. Comparative analyses of 37 grafts infused fresh during the one-year period preceding the pandemic were performed. Assessment of cellular therapy products included total nucleated cell and CD34+ cell enumeration, viability, and post-thaw recovery. The primary clinical endpoint was the evaluation of engraftment (absolute neutrophil count [ANC] and platelet count) and donor chimerism (presence of CD33+ and CD3+ donor cells) at day +30 and +100 post-transplant. Adverse events related to cell infusion were also analyzed. RESULTS: Patient characteristics were comparable between the fresh and cryopreserved groups with 2 exceptions in the HPC-A cohort: the number of patients in the cryopreserved group that received haploidentical grafts was 6 times that in the fresh group, and the number of patients in the fresh group with a Karnofsky performance score >90 was double that in the cryopreserved group. The quality of HPC-A and HPC-BM products was not affected by cryopreservation, and all grafts met the release criteria for infusion. The pandemic did not affect the time between collection and cryopreservation (median, 24 hours) and time in storage (median, 15 days). Median time to ANC recovery was significantly delayed in recipients of cryopreserved HPC-A (15 vs 11 days, P = .0121), and there was a trend toward delayed platelet engraftment (24 vs 19 days, P = .0712). The delay in ANC and platelet recovery was not observed when only matched graft recipients were compared. Cryopreservation did not affect the ability of HPC-BM grafts to engraft and reconstitute hematopoiesis, and there was no difference in the rates of ANC and platelet recovery. Achievement of donor CD3/CD33 chimerism was not affected by cryopreservation of either HPC-A or HPC-BM products. Graft failure was observed in only 1 case, a recipient of cryopreserved HPC-BM. Three recipients of cryopreserved HPC-A grafts died before ANC engraftment from infectious complications. Remarkably, 22% of our studied population had myelofibrosis, and almost half received cryopreserved HPC-A grafts with no graft failure observed. Finally, patients receiving cryopreserved grafts were at a higher risk of infusion-related adverse events than those receiving fresh grafts. CONCLUSIONS: Cryopreservation of allogeneic grafts results in adequate product quality with minimal impact on short-term clinical outcomes, except for an increased risk of infusion-related adverse events. Cryopreservation is a safe option in terms of graft quality and hematopoietic reconstitution with logistical benefits, but additional data are needed to determine long-term outcomes and assess whether this is a suitable strategy for at-risk patients.

Masks for prevention of respiratory viruses on the BMT unit: results of a quality initiative.

Respiratory viral infections (RVI) cause significant morbidity and mortality in hospitalized oncology patients. These viruses are easily spread from asymptomatic and/or symptomatic healthcare workers and visitors to immunocompromised patients, and literature review of facemasks for prevention of infection revealed mixed results. The Bone Marrow Transplant (BMT) Quality Assurance (QA) Committee at Mount Sinai began a surgical mask initiative on the BMT unit. The purpose of our initiative was to assess the impact of surgical mask implementation for healthcare workers and visitors on nosocomial RVI in all patients hospitalized on the BMT unit. We hypothesized that implementing surgical masks would reduce the number of hospital-acquired RVI. We performed a retrospective study involving all patients with malignancy hospitalized on the BMT unit for 4 years. During the latter 2 years, all healthcare workers and visitors were required to wear a surgical mask in every patient room on the BMT unit. Primary endpoint was incidence of RVI after implementation of surgical masks. The 2-year incidence of RVI in the pre-mask period was 14 out of a total of 15 001 patient days on the unit vs 2 out of 15 608 patient days after mask implementation. The difference in incidence of RVI within the two time intervals was noted to be statistically significant (P<.05, 2-proportion z-test). Our quality initiative demonstrated that surgical masks are an infection control modality that may provide benefit to oncology/BMT units by decreasing the risk for hospital-acquired RVI.

Serum Free Light Chain Assessment Early After Stem Cell Transplantation as a Prognostic Factor in Multiple Myeloma.

BACKGROUND: Multiple myeloma is an incurable cancer commonly treated with stem cell transplantation (SCT). Response is traditionally evaluated 100 days after SCT, both to allow for hematopoietic reconstitution and due to immunoglobulins' long half-lives. Free light chains (FLC) have significantly shorter half-lives and may provide evidence of response or treatment failure earlier after SCT. PATIENTS AND METHODS: We retrospectively studied 83 consecutive patients with multiple myeloma who underwent SCT and found 69 who had FLC measured 30 or 60 days after SCT. Using conventional FLC response criteria, we considered a patient to be at high risk for early relapse if he or she failed to experience a partial response by day 30 or 60. RESULTS: After a median overall follow-up of only 335 days, these high-risk patients had significantly shorter progression-free survival (median, 98 vs. 335 days, P = .001) and overall survival (366 days vs. median not reached, P = .016). CONCLUSION: Early FLC assessment either 1 or 2 months after SCT using standard FLC response criteria was able to identify a subset of patients at high risk of early relapse, and these patients may benefit from earlier interventions.