Allogeneic transplant following CAR T-cell therapy for large B-cell lymphoma.

Allogeneic hematopoietic cell transplantation (alloHCT) can potentially salvage large B-cell lymphoma (LBCL) patients experiencing treatment failure after chimeric antigen receptor T-cell therapy (CAR-T). Nonetheless, data on the efficacy and toxicities of alloHCT after receipt of CAR-T are limited. We report a multicenter retrospective study assessing the safety, toxicities, and outcomes of alloHCT in LBCL patients following CAR-T failure. Eighty-eight patients with relapsed, refractory LBCL received an alloHCT following anti-CD19 CAR-T failure. The median number of lines of therapy between CAR-T infusion and alloHCT was 1 (range 0-7). Low intensity conditioning was used in 77% (n=68) and peripheral blood was the most common graft source (86%, n=76). The most common donor types were matched unrelated donor (39%), followed by haploidentical (30%) and matched related donor (26%). Median follow-up of survivors was 15 months (range 1-72). One-year overall survival, progression-free survival, and graft-versus-host disease-free relapse-free survival were 59%, 45%, and 39% respectively. One-year non-relapse mortality and progression/relapse were 22% and 33% respectively. On multivariate analysis.

Impact of Donor and Recipient SARS-CoV-2 Vaccination or Infection on Immunity Post Hematopoietic Cell Transplantation

Background The role of donor and recipient COVID-19 immunologic status pre-transplant has not been fully investigated for allogeneic hematopoietic stem cell transplant (HSCT) recipients. Given poor immunogenicity to vaccines in this population and severe outcomes of COVID-19, adoptive transfer of immunity may offer important insights for improved protection for this vulnerable population. Objective To evaluate the role of adoptive transfer of immunity at one month post-transplant and six months post-transplant after vaccination of the recipient, based on SARS-CoV-2 vaccination and infection exposures of both the recipient and donor prior to transplant. Study Design Using banked specimens from related donor allogeneic HSCT recipients and clinical data for both donors and recipients, anti-Spike (S) IgG titers were analyzed at one-, three-, and six-months post-transplant according to prior SARS-CoV-2 immunologic exposures. Recipients were excluded if they had received SARS-CoV-2 monoclonal antibodies or had infection in the first six months after transplant. Results Of the 53 recipient-donor pairs, 29 donors and 24 recipients had prior SARS-CoV-2 immunologic exposures. Recipient-donor pairs with no prior SARS-CoV-2 exposures (D0R0) had significantly lower anti-S IgG titers at one month as compared to recipient-donor pairs with prior exposures (D1R1) (D0R0 median 2.43, IQR 0.41-3.77;D1R1 median 8.42, IQR 5.58 – 12.20;p = 0.008). At six months, anti-S IgG titers were higher in recipients who were vaccinated at three months post-transplant in the D1R1 cohort (median IgG 148.34, IQR 92.36-204.33) as compared to the D0R0 cohort (median IgG 38.74, IQR 8.93 - 119.71). Conclusions Current strategies should be optimized to enhance SARS-CoV-2 protection for HSCT recipients, including augmentation of the immune response for both the donors and recipients prior to transplant.

Impact of Donor and Recipient SARS-CoV-2 Vaccination or Infection on Immunity after Hematopoietic Cell Transplantation.

The role of donor and recipient Coronavirus disease 2019 (COVID-19) immunologic status pre-transplantation has not been fully investigated in allogeneic hematopoietic stem cell transplantation (HSCT) recipients. Given the poor immunogenicity to vaccines in this population and the serious outcomes of COVID-19, adoptive transfer of immunity may offer important insight into improving protection for this vulnerable population. In this study, we evaluated the role of adoptive transfer of immunity at 1 month post-transplantation and 6 months post-transplantation after vaccination of recipients, based on pre-transplantation severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and infection exposures of both recipient and donor. Using banked specimens from related donor allogeneic HSCT recipients and clinical data from both donors and recipients, anti-Spike (S) IgG titers were analyzed at 1, 3, and 6 months post-transplantation according to prior SARS-CoV-2 immunologic exposures. Recipients were excluded if they had received SARS-CoV-2 monoclonal antibodies or had infection in the first 6 months post-transplantation. Of the 53 recipient-donor pairs, 29 donors and 24 recipients had prior SARS-CoV-2 immunologic exposure. Recipient-donor pairs with no prior SARS-CoV-2 exposure (D0R0) had significantly lower anti-S IgG titers at 1 month compared to those with prior exposures (D1R1) (D0R0: median, 2.43 [interquartile range (IQR), .41 to 3.77]; D1R1: median, 8.42; IQR, 5.58 to 12.20]; P = .008). At 6 months, anti-S IgG titers were higher in recipients who were vaccinated at 3 months post-transplantation in the D1R1 cohort (median IgG, 148.34; IQR, 92.36 to 204.33) compared with the D0R0 cohort (median IgG, 38.74; IQR, 8.93 to 119.71). Current strategies should be optimized to enhance SARS-CoV-2 protection for HSCT recipients, including augmentation of the immune response for both donors and recipients prior to transplantation.

Enasidenib as maintenance following allogeneic hematopoietic cell transplantation for IDH2-mutated myeloid malignancies.

IDH2 (isocitrate dehydrogenase 2) mutations occur in approximately 15% of patients with acute myeloid leukemia (AML). The IDH2 inhibitor enasidenib was recently approved for IDH2-mutated relapsed or refractory AML. We conducted a multi-center, phase I trial of maintenance enasidenib following allogeneic hematopoietic cell transplantation (HCT) in patients with IDH2-mutated myeloid malignancies. Two dose levels, 50mg and 100mg daily were studied in a 3 × 3 dose-escalation design, with 10 additional patients treated at the recommended phase 2 dose (RP2D). Enasidenib was initiated between days 30 and 90 following HCT and continued for twelve 28-day cycles. Twenty-three patients were enrolled, of whom 19 initiated post-HCT maintenance. Two had myelodysplastic syndrome, and 17 had AML. All but 3 were in first complete remission. No dose limiting toxicities were observed, and the RP2D was established at 100mg daily. Attributable grade ≥3 toxicities were rare, with the most common being cytopenias. Eight patients stopped maintenance before completing 12 cycles, due to adverse events (n=3), pursuing treatment for graft-vs-host disease (GVHD) (n=2), clinician choice (n=1), relapse (n=1), and COVID infection (n=1). No cases of grade ≥3 acute GVHD were seen, and 12-month cumulative incidence of moderate/severe chronic GVHD was 42% (20-63%). Cumulative incidence of relapse was 16% (95% CI: 3.7-36%); 1 subject relapsed while receiving maintenance. Two-year progression-free and overall survival were 69% (95% CI: 39-86%) and 74% (95% CI, 44-90%), respectively. Enasidenib is safe, well-tolerated, with preliminary activity as maintenance therapy following HCT, and merits additional study. The study was registered at www.clinicaltrials.gov (#NCT03515512).

Severe Acute Respiratory Syndrome Coronavirus 2 Messenger RNA Vaccines in Allogeneic Hematopoietic Stem Cell Transplant Recipients: Immunogenicity and Reactogenicity.

The severe acute respiratory syndrome coronavirus 2 messenger RNA vaccine-induced humoral response and reactogenicity profile are described in allogeneic hematopoietic stem cell transplant (HSCT) recipients. Findings showed that 75.0% (by Simoa assay) or 80.0% (by Roche assay) of the HSCT cohort had a positive antibody response on series completion, compared with 100% in the healthy cohort.

Impact of cryopreservation and transit times of allogeneic grafts on hematopoietic and immune reconstitution.

We sought to evaluate the impact of cryopreservation of unrelated donor (URD) peripheral blood stem cell (PBSC) grafts on engraftment, chimerism, and immune reconstitution in the context of the COVID-19 pandemic. We reviewed stem cell product characteristics and clinical outcomes in 101 patients receiving cryopreserved PBSCs from URDs between January 1, 2019 and 31 December, 2020, compared with 203 patients receiving fresh URD PBSCs. We observed no differences in 6-month overall survival, progression-free survival, or nonrelapse mortality. Patients receiving cryopreserved PBSCs had delayed platelet engraftment and impaired reconstitution of white blood cells and T-cell subsets at day 30. Thirty-four percent of patients receiving cryopreserved grafts had CD3 chimerism <50% at day 30 after transplantation, compared with 14% of patients receiving fresh PBSCs (P = .0002). At day 100, this difference persisted (CD3+ chimerism <50%: 17% of cryopreserved cohort vs 6% of fresh cohort; P = .016). Greater product age at infusion was associated with increased graft failure, independent of cryopreservation. Receipt of grafts >48 hours old at time of cryopreservation or infusion significantly increased the risk of graft failure (subdistribution hazard ratio = 4.57; 95% confidence interval, 1.71-12.3; P = .0025). Our data indicate that cryopreservation is associated with similar overall short-term clinical outcomes compared with fresh PBSC. However, patients must be monitored closely for increased risk of other potentially adverse outcomes, including graft failure and poor immune recovery, particularly for grafts with older overall age at infusion. Longer-term follow-up is needed to determine impact on relapse and survival.

COVID-19 and hematopoietic stem cell transplantation and immune effector cell therapy: a US cancer center experience.

The novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), identified in late 2019 as the causative agent of COVID-19, was declared a pandemic by the World Health Organization on 11 March 2020. Widespread community transmission in the United States triggered a nationwide shutdown, raising major challenges for administration of hematopoietic stem cell transplant (HSCT) and chimeric antigen receptor (CAR)-T cell therapies, leading many centers to delay or cancel operations. We sought to assess the impact of the COVID-19 pandemic on operations and clinical outcomes for HSCT and CAR-T cellular therapies at the Dana-Farber Cancer Institute by reviewing administration and outcomes in 127 cell therapy patients treated during the initial COVID-19 surge: 62 adult allogeneic HSCT (allo-HSCT), 38 autologous HSCT (auto-HSCT), and 27 CAR-T patients. Outcomes were compared with 66 allo-HSCT, 43 auto-HSCT, and 33 CAR-T patients treated prior to the pandemic. A second control cohort was evaluated for HSCT groups to reflect seasonal variation in infections. Although there were changes in donor selection and screening as well as cryopreservation patterns of donor products, no differences were observed across groups in 100-day overall survival, progression-free survival, rates of non-COVID-19 infections, including hospital length of stay, neutrophil engraftment, graft failure, acute graft-versus-host disease in allo-HSCT patients, or cytokine release syndrome and neurotoxicity in CAR-T patients. No HSCT patients contracted COVID-19 between days 0 and 100. One CAR-T patient contracted COVID-19 at day +51 and died of the disease. Altogether, our data indicate that cellular therapies can be safely administered throughout the ongoing COVID-19 pandemic with appropriate safeguards.