Sequential treatment with FLAG-IDA/treosulfan conditioning regimen for patients with active acute myeloid leukemia.

Sequential protocols combining salvage chemotherapy with reduced intensity conditioning (RIC) and allogeneic hematopoietic cell transplantation (alloHCT) for high-risk acute myeloid leukemia (AML) have been studied more than a decade. Purpose of this retrospective analysis was to evaluate the anti-leukemic efficacy and toxicity of FLAG-IDA protocol (fludarabine, cytarabine, and idarubicin) followed by treosulfan-based conditioning for patients with active AML. From January 2014 to November 2019, a total of 29 active AML patients [median age, 64 years (range, 23-73)] were treated. All patients completed protocol regimen and were transplanted. Five patients (17%) had grade 3-4 toxicities; therefore, treosulfan was substituted with total body irradiation (TBI) non-myeloablative conditioning. Six (20%) patients died within 30 post-transplant days, all from infectious complications. Out of 23 evaluable patients on day 30, 22 (96%) achieved complete hematologic remission with full donor chimerism. Non-relapse mortality (NRM) rates at 1 and 3 years were 22% and 49%, respectively. Median overall survival (OS) was 12 (95% CI, 4-20) months. OS and disease-free survival were 50% and 46% at 1 year and 28% and 17% at 2 years, respectively. Age, gender, disease burden, number of previous lines, and comorbidity score did not predict survival. Sequential strategy combining FLAG-IDA and treosulfan may offer a salvage option for few selected patients with active AML; however, high NRM presents a major obstacle to treatment success. Future efforts should focus on reducing NRM by moderating regimen intensity and by better selection of patients.

Humoral serological response to the BNT162b2 vaccine after allogeneic haematopoietic cell transplantation.

OBJECTIVES: To assess the humoral immune response to the BNT162b2 vaccine after allogeneic haematopoietic cell transplantation (HCT). METHODS: This is a prospective cohort study. The SARS-CoV-2 IgGII Quant (Abbott©) assay was performed 4-6 weeks after the second BNT162b2 vaccine for quantitative measurement of anti-spike antibodies. RESULTS: The cohort included 106 adult patients. Median time from HCT to vaccination was 42 (range 4-439) months. Overall, 15/106 (14%, 95% confidence interval (CI) 7-21%) were seronegative despite vaccination, 14/52 patients on immunosuppression (27%, 95%CI 19-35%) compared to only 1/54 patients off immunosuppression (1.8%, 95%CI 1-4%) (p 0.0002). The proportion of seronegative patients declined with time; it was 46% (6/13) during the first year, 12.5% (3/24) during the second year and 9% (6/69) beyond 2 years from transplant. Patients with acute graft-versus-host disease (GVHD) (odds ratio (OR) 3.3, 95%CI 0.97-11.1, p 0.06) and moderate to severe chronic GVHD (OR 5.9, 95%CI 1.2-29, p 0.03) were more likely to remain seronegative. Vaccination was well tolerated by most patients. However, 7% (7/106) reported that GVHD-related symptoms worsened within days following vaccination. CONCLUSION: A significant proportion of allogeneic HCT recipients receiving immunosuppression demonstrated an inadequate humoral response to the BNT162b2 vaccine. These patients should be recognized and instructed to take appropriate precautions. Recipients who were off immunosuppression had a humoral response that was comparable to that of the general population.

Efficacy of folinic acid rescue following MTX GVHD prophylaxis: results of a double-blind, randomized, controlled study.

The use of methotrexate (MTX) for graft-versus-host disease (GVHD) prophylaxis is associated with increased rates of organ-specific toxicities. Despite limited data, the European Society for Blood and Marrow Transplantation-European LeukemiaNet working group recommend the use of folinic acid (FA) rescue to reduce MTX toxicity after allogeneic hematopoietic cell transplantation (allo-HCT). In a multicenter, double-blind, randomized, controlled trial, we explored whether FA rescue reduces MTX-induced toxicity. We enrolled patients undergoing allo-HCT with myeloablative conditioning with peripheral blood stem cell grafts, with GVHD prophylaxis consisting of cyclosporine and MTX. Patients were randomized to receive FA or placebo starting 24 hours after each MTX dose and continuing over 24 hours in 3 to 4 divided doses. The primary end point was the rate of grades 3 and 4 oral mucositis. After enrollment of 52 patients (FA, n = 28; placebo, n = 24), preplanned interim analysis revealed similar rates of grade 3 and 4 (46.6% vs 45.8%; P = .97) and grades 1 to 4 (83.3% vs 77.8%; P = .65) oral mucositis. With a median follow-up of 17 (range, 4.5-50) months, there was no difference in the rates of acute and chronic GVHD, disease relapse, nonrelapse mortality, and overall survival. These interim results did not support continuation of the study. We conclude that FA rescue after MTX GVHD prophylaxis does not decrease regimen-related toxicity or affect transplantation outcomes. This study was registered at clinicaltrials.gov as #NCT02506231.

Human herpes virus 6 reactivation following autologous hematopoietic cell transplantation - a single-center experience.

Data regarding presentation and management of human herpes virus 6 (HHV-6) reactivation among autologous hematopoietic cell transplantation (HCT) recipients are limited. We retrospectively reviewed medical charts of all autologous HCT patients tested for HHV-6 reactivation due to suspected clinical presentation between 1/2012 and 8/2017. Among 328 autologous HCT recipients, 44 patients were tested for HHV-6 reactivation. Thirty patients tested positive; 29 (97%) had sustained fever, six (20%) had rash and four (13%) had pneumonia. Median C-reactive protein was significantly lower in HHV-6 positive patients compared to negative patients (3.6 (range, 0.4-11) vs. 9.6 (range, 3.2-30) mg/dL, respectively, p = .004). Ganciclovir formulations were administrated in 29 (97%) patients with median time to fever resolution of one (range, 1-2) day. HHV-6 should be considered as an important cause of post engraftment fever in autologous HCT. Larger studies are warranted to evaluate incidence of HHV-6 reactivation and optimal treatment regimen.