Cytomegalovirus Infection after CD34(+)-Selected Hematopoietic Cell Transplantation

Immune reconstitution, vaccine responses, and rituximab use after ex-vivo CD34-selected myeloablative allogenic hematopoietic cell transplantation

Myeloablative T cell depleted (CD34-selected) hematopoietic cell transplantation (HCT) is associated with less acute and chronic graft versus host disease (GVHD). We aimed to examine vaccine responses in relation to immune reconstitution and post HCT rituximab administration in this population. This single center retrospective study included 251 patients with hematological malignancies who received a first CD34-selected HCT between 2012 and 2015. Of 251 patients, 190 were alive 1 year after HCT. Among the entire population, 77 (30.7%) patients were vaccinated. After vaccine administration, 35/44 (80%), 30/75 (40%), 27/36 (75%), 33/65 (51%), 34/51 (51%), 22/28 (79%) and 20/34 (59%) of evaluable patients had protective antibody titers for haemophilus influenzae type B (Hib), Pneumococcus, Tetanus, Diphtheria, Pertussis, hepatitis A (HAV), and hepatitis B (HBV) respectively. Responders to the pneumococcal vaccine had a higher CD45RA T cell count than non responders, with 12/18 patients (66.7%) vs 11/32 (34.4%) p = 0.04. For pneumococcal vaccine, there was also a trend to higher total lymphocyte B cell count in responders vs non responders p = 0.06. Rituximab post HCT was given to 59/251 (23.5%) patients. No difference was found in immune reconstitution patterns for rituximab use between vaccine responders and not. Recipients of CD34-selected HCT may respond to vaccination, and T and B cell subsets could be useful to predict vaccine response.

Emergence of human CMV-induced NKG2C+ NK cells is associated with CD8+ T-cell recovery after allogeneic HCT

Cytomegalovirus (CMV) infection is associated with the expansion of a mature NKG2C+FcεR1γ- natural killer (NK) cell population. The exact mechanism underlying the emergence of NKG2C+ NK cells, however, remains unknown. Allogeneic hematopoietic cell transplantation (HCT) provides an opportunity to longitudinally study lymphocyte recovery in the setting of CMV reactivation, particularly in patients receiving T-cell-depleted (TCD) allografts. We analyzed peripheral blood lymphocytes from 119 patients at serial time points after infusion of their TCD allograft and compared immune recovery with that in samples obtained from recipients of T-cell-replete (T-replete) (n = 96) or double umbilical cord blood (DUCB) (n = 52) allografts. NKG2C+ NK cells were detected in 92% (45 of 49) of recipients of TCD HCT who experienced CMV reactivation. Although NKG2A+ cells were routinely identifiable early after HCT, NKG2C+ NK cells were identified only after T cells could be detected. T-cell reconstitution occurred at variable times after HCT among patients and predominantly comprised CD8+ T cells. In patients with CMV reactivation, recipients of TCD HCT expressed significantly higher frequencies of NKG2C+ and CD56neg NK cells compared with patients who received T-replete HCT or DUCB transplantation. NKG2C+ NK cells after TCD HCT were CD57+FcεR1γ+ and degranulated significantly more in response to target cells compared with the adaptive the NKG2C+CD57+FcεR1γ- NK cell population. We conclude that the presence of circulating T cells is associated with the expansion of a CMV-induced NKG2C+ NK cell population, a potentially novel example of developmental cooperation between lymphocyte populations in response to viral infection.

Cost Effectiveness of Letermovir for Cytomegalovirus Prophylaxis Compared with Pre-Emptive Therapy in Allogeneic Hematopoietic Stem Cell Transplant Recipients in the United States

PURPOSE

The aim of this study was to assess the cost effectiveness of letermovir prophylaxis with the option for subsequent pre-emptive therapy (PET) for the prevention of cytomegalovirus (CMV) infection compared with a PET-only scenario in adult allogeneic hematopoietic stem cell transplant (allo-HCT) recipients in the United States over a 10-year time horizon.

MATERIALS AND METHODS

A publicly available decision tree model was constructed using a commercial third-party payer perspective to simulate an allo-HCT recipient's clinical trajectory in the first-year post-transplant, followed by entry to a Markov model to simulate years 2 through 10. Clinical inputs and utility estimates were derived from published literature. Costs were derived from published literature and US Department of Veterans Affairs Federal Supply Schedule drug pricing. Outcomes assessed included life expectancy, quality-adjusted life-years (QALYs), direct medical costs, and the incremental cost-effectiveness ratio (ICER). One-way and probabilistic sensitivity analyses (PSA) were performed to test the robustness of the findings.

RESULTS

Compared with PET alone, letermovir prophylaxis was projected to increase life-years per person (4.99 vs. 4.70 life-years), and increase QALYs (3.29 vs. 3.08) and costs (US$83.411 vs. US$70,698), yielding an ICER of US$59,356 per QALY gained. One-way sensitivity analyses indicated our model was sensitive to mortality (ICER: $164,771/QALY) and utility (letermovir ICER: $117,447/QALY; PET ICER: $107,290/QALY) in the first-year post-transplant. In 57.1% of the PSA simulations, letermovir was a cost-effective option using a willingness-to-pay threshold of US$100,000 per QALY.

CONCLUSIONS

Letermovir prophylaxis is cost effective compared with PET alone with a willingness-to-pay threshold of US$100,000 per QALY gained. Sensitivity analysis results indicate future research is required to understand the impact of mortality and quality of life in the first-year post-transplant to arrive at a conclusive decision on letermovir adoption.

How I prevent viral reactivation in high-risk patients

Preventing viral infections at an early stage is a key strategy for successfully improving transplant outcomes. Preemptive therapy and prophylaxis with antiviral agents have been successfully used to prevent clinically significant viral infections in hematopoietic cell transplant recipients. Major progress has been made over the past decades in preventing viral infections through a better understanding of the biology and risk factors, as well as the introduction of novel antiviral agents and advances in immunotherapy. High-quality evidence exists for the effective prevention of herpes simplex virus, varicella-zoster virus, and cytomegalovirus infection and disease. Few data are available on the effective prevention of human herpesvirus 6, Epstein-Barr virus, adenovirus, and BK virus infections. To highlight the spectrum of clinical practice, here we review high-risk situations that we handle with a high degree of uniformity and cases that feature differences in approaches, reflecting distinct hematopoietic cell transplant practices, such as ex vivo T-cell depletion.

Ex vivo and in vivo T-cell depletion in allogeneic transplantation: towards less or non-cytotoxic conditioning regimens

INTRODUCTION

Although tremendous progress has been made since the introduction of allogeneic hematopoietic stem cell transplantation (HSCT) decades ago, there are still many obstacles to overcome. A major obstacle is the presence of T-lymphocytes in the recipient and in the donor. Recipient-derived T-lymphocytes not eliminated by the conditioning regimen are a major barrier and can lead to mixed chimerism or to complete rejection of the graft. Donor-derived T-lymphocytes can induce severe acute and chronic Graft-versus-Host Disease (GvHD).

AREAS COVERED

Currently published strategies for in vivo depletion of recipient-derived T-lymphocytes are discussed including the increase of the intensity of the conditioning regimen, the addition of anti-thymocyte globulin (ATG) or the anti-CD52 monoclonal antibody Campath. For the depletion or tolerization of the donor-derived T-lymphocytes, ex vivo-T-cell depletion methods, such as positive selection of CD34+ stem cells, negative depletion of CD3+ or TcRαβ+ T-lymphocytes or the use of post-transplant cyclophosphamide (PTCy) have been developed.

EXPERT COMMENTARY

All these currently used approaches have their disadvantages and new approaches should be investigated. In this review, we discuss current and propose new possible strategies to overcome the HLA barrier by using more specific T-cell directed therapies and/or by the combinations of current methods.

Time to initiation of pre-emptive therapy for cytomegalovirus impacts overall survival in pediatric hematopoietic stem cell transplant recipients

BACKGROUND AIMS

Cytomegalovirus (CMV) reactivation is a significant complication following allogeneic hematopoietic stem cell transplant (HSCT) and affects upwards of 40% of pediatric HSCT patients. Pre-emptive therapy remains the only effective treatment strategy available for pediatric patients following CMV reactivation. Little is known about how the timing of induction treatment following CMV reactivation impacts outcomes in pediatric patients, especially following ex vivo T-cell-depleted (TCD) HSCT.

METHODS

The authors evaluated how the timing of induction treatment after CMV reactivation impacts overall survival (OS) and CMV disease in pediatric patients undergoing TCD HSCT at a single institution. The authors retrospectively analyzed patients treated on the pediatric service who received an initial ex vivo TCD HSCT at Memorial Sloan Kettering Cancer Center (MSKCC) from January 2010 to June 2018. CMV reactivation was defined as ≥1 CMV polymerase chain reaction >500 copies/mL in whole blood or >137 IU/mL in plasma within the first 180 days after allogeneic HSCT. To analyze the impact of the timing of induction treatment, the authors' primary study outcome was OS and secondary outcome was CMV disease.

RESULTS

A total of 169 patients who underwent an initial allogeneic TCD HSCT on the pediatric service at MSKCC from January 2010 to June 2018 were included in the analysis. Thirty-seven (22%) patients reactivated CMV during the first 180 days following HSCT. Of those patients who reactivated CMV, CMV donor/recipient (D/R) serostatus was as follows: D+/R+ n = 28 (76%) and D-/R+ n = 9 (24%). There was no CMV reactivation observed among recipients who were CMV-seronegative irrespective of donor serostatus. In those patients who reactivated CMV, the median time from HSCT to CMV reactivation was 24 days (interquartile range, 20-31). Eleven patients ultimately developed CMV disease in addition to CMV viremia, whereas the remaining patients had only CMV viremia. The cumulative incidence of CMV reactivation at 60 days was 45.2% (95% confidence interval [CI], 32.8-57.5) in the D+/R+ subgroup and 31% (95% CI, 14.2-47.9) in the D-/R+ subgroup. For those patients who reactivated CMV, 30 (81%) received induction treatment with ganciclovir or foscarnet. To analyze the impact of the timing of induction treatment on clinical outcomes, the authors restricted the analysis to those patients who reactivated CMV and received induction treatment (n = 30). The timing of induction treatment was significantly associated with OS, with optimal timing of initiation within a week of CMV reactivation (P = 0.02). There was no significant impact on the timing of induction treatment and risk of CMV disease (P = 0.30).

CONCLUSIONS

In ex vivo TCD HSCT in pediatric patients, early initiation of induction treatment after CMV reactivation is associated with improved OS.

Major pulmonary complications following Hematopoietic stem cell transplantation: What the pulmonologist needs to know

Hematopoietic stem cell transplantation (HSCT) is used for treatment of a myriad of both malignant and non-malignant disorders. However, despite many advances over the years which have resulted in improved patient mortality, this subset of patients remains at risk for a variety of post-transplant complications. Pulmonary complications of HSCT are categorized into infectious and non-infectious and occur in up to one-third of patients undergoing HSCT. Infectious etiologies include bacterial, viral and fungal infections, each of which can have significant mortality if not identified and treated early in the course of infection. Advances in the diagnosis and management of infectious complications highlight the importance of non-infectious pulmonary complications related to chemoradiation toxicities, immunosuppressive drugs toxicities, and graft-versus-host disease. This report aims to serve as a guide and clinical update of pulmonary complications following HSCT for the general pulmonologist who may be involved in the care of these patients.

αβ T-cell graft depletion for allogeneic HSCT in adults with hematological malignancies

We conducted a multicenter prospective single-arm phase 1/2 study that assesses the outcome of αβ T-cell depleted allogeneic hematopoietic stem cell transplantation (allo-HSCT) of peripheral blood derived stem cells from matched related, or unrelated donors (10/10 and 9/10) in adults, with the incidence of acute graft-versus-host disease (aGVHD) as the primary end point at day 100. Thirty-five adults (median age, 59; range, 19-69 years) were enrolled. Conditioning consisted of antithymocyte globulin, busulfan, and fludarabine, followed by 28 days of mycophenolic acid after allo-HSCT. The minimal follow-up time was 24 months. The median number of infused CD34+ cells and αβ T cells were 6.1 × 106 and 16.3 × 103 cells per kg, respectively. The cumulative incidence (CI) of aGVHD grades 2-4 and 3-4 at day 100 was 26% and 14%. One secondary graft failure was observed. A prophylactic donor lymphocyte infusion (DLI) (1 × 105 CD3+ T cells per kg) was administered to 54% of the subjects, resulting in a CI of aGVHD grades 2-4 and 3-4 to 37% and 17% at 2 years. Immune monitoring revealed an early reconstitution of natural killer (NK) and γδ T cells. Cytomegalovirus reactivation associated with expansion of memory-like NK cells. The CI of relapse was 29%, and the nonrelapse mortality 32% at 2 years. The 2-year CI of chronic GVHD (cGVHD) was 23%, of which 17% was moderate. We conclude that only 26% of patients developed aGVHD 2-4 after αβ T-cell-depleted allo-HSCT within 100 days and was associated with a low incidence of cGVHD after 2 years. This trial was registered at www.trialregister.nl as #NL4767.

Universal Engraftment after Allogeneic Hematopoietic Cell Transplantation Using Cryopreserved CD34-Selected Grafts

As a result of the COVID-19 pandemic, most centers performing allogeneic hematopoietic cell transplantation (allo-HCT) have switched to the use of cryopreserved grafts. Previous investigators have suggested that cryopreserved allografts may heighten risk of nonengraftment. To date, no study has investigated the effect of cryopreservation of CD34-selected hematopoietic progenitor cells (CD34⁺ HPCs) used as the sole graft source. In this study, we sought to evaluate outcomes after unrelated donor or matched sibling allo-HCT with cryopreserved CD34⁺ HPCs. This was a single-center analysis of adult patients with hematologic malignancies who underwent allo-HCT with cryopreserved CD34-selected allo-HCT grafts between January 2010 and June 2017. All patients received ablative conditioning and antirejection prophylaxis with rabbit antithymocyte globulin. G-CSF-mobilized leukapheresis products underwent CD34 selection using the CliniMACS Reagent System. Cells were then cryopreserved in DMSO (final concentration 7.5%) to -90 °C using a controlled-rate freezing system before being transferred to vapor-phase liquid nitrogen storage. In internal validation, this method has shown 92% mean CD34⁺ cell viability and 99.7% mean CD34⁺ cell recovery. Engraftment was defined as the first of 3 consecutive days of an absolute neutrophil count of ≥0.5. Platelet recovery was recorded as the first of 7 consecutive days with a platelet count ≥20 K/μL without transfusion. Kaplan-Meier methodology was used to estimate overall survival (OS) and relapse-free survival (RFS), and cumulative incidence functions were used to estimate rates of relapse, nonrelapse mortality (NRM), and acute graft-versus-host disease (GVHD). A total of 64 patients received a cryopreserved CD34-selected graft. The median CD34⁺ cell count before cryopreservation was 6.6 × 10⁶/kg (range, 1.4 to 16.1 × 10⁶/kg), and the median CD3⁺ cell count was 2.0 × 10³/kg (range, 0 to 21.1 × 10⁶/kg). All patients were engrafted, at a median of 11 days post-HCT (range, 8 to 14 days). One patient had poor graft function in the setting of cytomegalovirus viremia, necessitating a CD34-selected boost on day +57. The median time to platelet recovery was 16 days (range, 13 to 99 days). The estimated 2-year OS was 70% (95% confidence interval [CI], 58% to 83%) with cryopreserved grafts versus 62% (95% CI, 57% to 67%) with fresh grafts (hazard ratio [HR], 0.86; 95% CI, 0.54 to 1.35; P = .5). The estimated 2-year RFS in the 2 groups was 59% (95% CI, 48% to 74%) versus 56% (95% CI, 51% to 61%; HR, 1.01; 95% CI, 0.68 to 1.51; P > .9). The cumulative incidence of relapse at 2 years was 29% (95% CI, 17% to 41%) versus 23% (95% CI, 19% to 27%; P = .16), and the cumulative incidence of NRM at 2 years was 17% (95% CI, 9% to 28%) versus 23% (95% CI, 19% to 28%; P = .24). The cumulative incidence of grade II-IV acute GVHD by day +100 was 16% with cryopreserved grafts (95% CI, 8% to 26%) and 16% (95% CI, 13% to 20%; P = .97) with fresh grafts. Moderate to severe chronic GVHD by day +365 occurred in only 1 recipient of a cryopreserved graft (2%). Our data show that in patients with hematologic malignancies who received cryopreserved allogeneic CD34⁺ HPCs, engraftment, GVHD, and survival outcomes were consistent with those seen in recipients of fresh allogeneic CD34⁺ HPC grafts at our center. Our laboratory validation and clinical experience demonstrate the safety of our cryopreservation procedure for CD34-selected allografts.

CMV viral load kinetics predict CMV end-organ disease and mortality after hematopoietic cell transplant (HCT)

BACKGROUND

We investigated the association between time-averaged area under the curve (AAUC) of CMV viral load (VL) by D100 and overall survival (OS) at one-year post-hematopoietic cell transplantation (HCT).

METHODS

A retrospective cohort study, including patients receiving HCT between 2010.6 and 2017.12 from Memorial Sloan Kettering Cancer Center. AAUC was calculated for patients with detected VL. Patients were categorized into "non-controllers" (Q4) and "controllers" (Q1-3) using the highest AAUC quartile as cutoff. Kaplan-Meier analyses and Cox models were used to estimate the association between AAUC and OS. Patients with non-detected CMV VL were categorized into "elite-controllers" (R+ or R-/D+) and "R-/D-".

RESULTS

The study (N=952) included 282 controllers, 93 non-controllers, 275 elite-controllers, and 302 R-/D-. OS was 80.1% and 58.1% for controllers and non-controllers, respectively. In multivariable models, non-controllers had worse OS versus controllers (adjusted hazard ratio [HR] 2.65, 95% CI 1.71-4.12). In landmark analyses, CMV controllers had similar OS as elite-controllers (HR 1.26, 95% CI 0.83-1.91) or R-/D- (HR 0.98, 95% CI 0.64-1.5).

CONCLUSION

CMV non-controllers had worse OS at one-year post-HCT. CMV controllers had similar OS as elite-controllers or R-/D-. Future studies are needed to validate our AAUC cutoff across different cohorts and CMV management strategies.

Letermovir for Prevention of Cytomegalovirus Reactivation in Haploidentical and Mismatched Adult Donor Allogeneic Hematopoietic Cell Transplantation with Post-Transplantation Cyclophosphamide for Graft-versus-Host Disease Prophylaxis

Cytomegalovirus (CMV) is serious viral infection in allogeneic hematopoietic cell transplantation (allo-HCT) recipients. November 2017, the novel CMV DNA terminase complex inhibitor letermovir was approved for prophylaxis of CMV infection in CMV-seropositive allo-HCT recipients. Here we sought to determine the effectiveness of letermovir in preventing CMV infection in CMV-seropositive patients undergoing haploidentical or mismatched adult unrelated donor allo-HCT using post-transplantation cyclophosphamide-based graft-versus host-disease prophylaxis. Sixty-four patients underwent transplantation between 2014 and 2019, of whom 32 received letermovir and 32 did not receive letermovir. The day 180 cumulative incidence of CMV infection requiring therapy was 45.3% (95% confidence interval [CI], 32.7% to 57.1%) in the entire cohort, 68.8% (95% CI, 48.9% to 82.2%) in the patients who did not receive letermovir, and 21.9% (95% CI, 9.5% to 37.6%; P < .001) in patients who received letermovir. Adjusting for regimen intensity, disease histology, and age, the hazard ratio for CMV infection was .19 (95% CI, .08 to .47; P < .001) in patients who received primary prophylaxis with letermovir. The 1-year cumulative incidence of treatment- related mortality was similar between patients with and without letermovir treatment (16.9% versus 18.9%), as was overall survival (64.0% versus 49.0%). Persistent CMV infection requiring >28 days of therapy was more common in patients who did not receive letermovir (31.2% versus 6.2%; P = .02). In summary, letermovir was effective in preventing CMV infection in this high-risk population of HLA-mismatched allo-HCT recipients.

Therapeutic advantages provided by banked virus-specific T-cells of defined HLA-restriction

We have developed banks of EBV and CMV-specific T-cell lines generated from healthy seropositive third party donors and characterized them as to their HLA type, virus specificity, lack of alloreactivity, and HLA restriction. We here summarize results of studies employing these immediately accessible, broadly-applicable third party virus-specific T-cells for adoptive therapy of EBV lymphomas and CMV infections in allo-HCT recipients. We describe the characteristics contributing to their safety. We also discuss several distinctive advantages of banked third party virus-specific T-cells selected on the basis of their HLA restriction, particularly in the treatment of Rituximab-non-responsive EBV⁺ lymphomas and drug refractory CMV infections complicating HLA non-identical transplants.

Impact of Preemptive Therapy for Cytomegalovirus on Hospitalizations and Cost after Hematopoietic Stem Cell Transplantation

Cytomegalovirus (CMV) viremia occurs in 40% to 80% of CMV-seropositive (R+) recipients of allogeneic hematopoietic cell transplantation (HCT). The preemptive therapy (PET) strategy has reduced the risk of CMV end-organ disease (EOD) and associated mortality but may lead to substantial healthcare resource utilization (HCRU) and costs. Real-world data on the economic impact of PET is relevant for the evaluation of alternative strategies for CMV management. We examined the impact of clinically significant CMV treated with PET on inpatient length of stay (LOS), number of readmissions, and associated costs from day 0 through day 180 post-HCT. This was a retrospective study of R+ adults who underwent peripheral blood or marrow allogeneic HCT at Memorial Sloan Kettering Cancer Center between March 2013 and December 2017. Patients were routinely screened for CMV by qPCR and received PET according to institutional standards of care. Data were extracted from electronic medical records and hospital databases. Itemized cost data per patient were obtained from the Vizient database, adjusted to 2017 dollars using inflation indices. Study outcomes included HCRU evaluated by inpatient LOS and inpatient cost in patients who received PET for clinically significant CMV (PET group) compared with those who did not receive PET (no PET group) and the frequency and cost of CMV-related readmissions compared with non CMV-related readmissions. We used generalized linear models to examine the incremental HCRU and costs associated with PET controlling for other potential factors. Of 357 patients, PET was initiated in 208 (58.3%), at a median of 35 days after HCT. By day 180, 23 patients (6.4%) had developed CMV EOD and 3 (.8%) had died of CMV. Compared with the no PET group, the PET group had a longer LOS for HCT admission (P = .0276), longer total LOS by day 180 (P = .0001), a higher number of readmissions (P = .0001), a higher mean inpatient cost for HCT admission ($189,389 versus $151,646; P = .0133), and a higher total inpatient cost ($297,563 versus $205,815; P < .0001). Among PET recipients, CMV-related readmissions were associated with higher mean cost per episode compared with non CMV-related readmissions ($165,455 versus $89,419; P = .005). CMV-related readmissions comprised 40.6% of total all-cause readmissions and incurred 55.9% of total all-cause readmission costs in PET recipients. Our data show that patients treated with currently available PET had greater inpatient HCRU and cost, by day 180 compared with patients who did not receive PET. The cost of CMV-related readmissions accounted for 56% of total readmission cost among PET recipients. Future studies are needed to examine the cost-effectiveness of alternative strategies for CMV management.

Impact of Preemptive Therapy for Cytomegalovirus on Toxicities after Allogeneic Hematopoietic Cell Transplantation in Clinical Practice: A Retrospective Single-Center Cohort Study

(Val)ganciclovir (vGCV) or foscarnet (FCN) as preemptive therapy (PET) for cytomegalovirus (CMV) after allogeneic hematopoietic cell transplantation (HCT) is associated with myelosuppression and nephrotoxicity, respectively. We analyzed a cohort of CMV-seropositive (R⁺) HCT recipients managed preemptively at a single center. The objectives of our study were to (1) quantify the frequencies of neutropenia and acute kidney injury (AKI) through day +100 (D100) post-HCT and at PET discontinuation and (2) assess the impact of PET on neutropenia and AKI in multivariate models. This was a retrospective cohort study of adult CMV R⁺ recipients who underwent allo-HCT at Memorial Sloan Kettering Cancer Center from March 18, 2013, through December 31, 2017, and were managed with PET. Patients were grouped by receipt of PET (PET and no PET). Neutropenia and AKI were defined by Common Terminology Criteria for Adverse Events version 4. Frequencies of toxicities by D100 were compared between relevant groups. The impact of PET on toxicities was examined in univariate and multivariate Poisson/negative binomial regression models. Of 368 CMV R⁺ HCT recipients, 208 (56.5%) received PET. Neutropenia by D100 occurred in 41.8% and 28.6% patients in PET and no PET, respectively (P = .0009). PET increased the risk of neutropenia (adjusted relative risk = 1.81; 95% confidence interval [CI], 1.48 to 2.21; P < .0001) in multivariate analyses. AKI by D100 occurred in 12.0% and 7.8% patients in PET and no PET, respectively (P = .19). PET increased the risk of AKI by 2.75-fold (95% CI, 1.71 to 4.42; P < .0001). When PET recipients were grouped by first antiviral, neutropenia by D100 occurred in 34.8% and 48.9% of vGCV and FCN recipients, respectively, (P = .08), and AKI occurred in 13.0% and 34.0% of vGCV and FCN recipients, respectively (P = .001). At discontinuation of vGCV or FCN, neutropenia was present in 11.2% versus 2.1% patients, respectively (P = .08), and AKI was present in 1.9% of versus 12.8% patients respectively (P = .005). Preemptive therapy for CMV increased the risk of neutropenia and AKI in the first 100 days post-HCT by 1.8-fold and 2.8-fold, respectively. Our results underscore the need for safer antivirals for CMV management in HCT recipients.

Global estimate of phenotypic and genotypic ganciclovir resistance in cytomegalovirus infections among HIV and organ transplant patients; A systematic review and meta-analysis

Human cytomegalovirus (CMV), an opportunistic pathogen belonging to Herpesviridae family, is considered as one of the major causes of morbidity and mortality among wide variety of patients, particularly in transplant recipients and HIV positive patients. As this virus can be resistant to treatment, frequency of CMV in patients who receive organ transplantation and people suffering from AIDS was studied between 1980 and 2019. Medline (via PubMed), Embase, Web of Science, and the Iranian Database were reviewed, and Comprehensive Meta-Analysis (V2.0, Biostat) software analyzed all data. Finally, we used Cochran's Q-statistic to encounter heterogeneity between different studies. Meta-analyses indicated, GCV resistance was 14.1% (95% CI 11.2-17.7); however, in patients suffering from AIDS and organ transplantation were 19.5% (95% CI 14.7-25.4) and 11.4% (95% CI 8.1-15.8), respectively. There were increasing rates in the prevalence of GCV resistance in CMV among transplant recipients, and HIV positive patients. Therefore, evaluation of these refractory infections is beneficial.

Cytomegalovirus infection and associated hospitalization and costs among individuals undergoing allogeneic hematopoietic stem cell transplant

Objective: This study utilized a large, national US database to explore the impact of Cytomegalovirus (CMV) infection on hospital services utilization and costs during the first 100 days following allogeneic hematopoietic stem cell transplant (allo-HSCT).Methods: This retrospective, observational cohort study used data from the Premier Healthcare database to identify patients undergoing their first (index) allo-HSCT procedure between 1 January 2006 and 31 March 2015. Three subgroups were analyzed according to CMV-related readmissions during the 100-day follow-up (0, 1, or 2+ readmissions) to compare healthcare utilization and costs.Results: A total of 1610 patients (mean age, 50.5 years; 56.9% male) from 52 US hospitals met the inclusion criteria. During follow-up, 212 (13.2%) patients had 1 (n = 161; 10.0%) or 2+ (n = 51; 3.2%) CMV-related readmissions. The mean ± SD number of all follow-up encounters (inpatient admissions and hospital-based outpatient visits) was similar for the no CMV (3.9 ± 3.9), 1 CMV (3.7 ± 3.9), and 2+ CMV (4.5 ± 3.8) readmission groups (p = .439). Mean total costs of hospital-based healthcare encounters (inpatient admissions and hospital-based outpatient visits) during follow-up were significantly greater in patients who had a CMV readmission ($111,729 [1 CMV readmission]; $184,021 [2+ CMV readmissions]) compared to those without a CMV readmission ($46,064; p < .001]. 100-day follow-up mortality was higher in the CMV vs. non-CMV readmission groups (30.2 vs. 8.2%; p < .001).Conclusions: This large, national database study revealed significantly higher healthcare utilization and costs, as well as mortality, among patients with CMV-related re-hospitalization during the first 100 days post-transplant as compared to patients without CMV-related hospitalization.

Allogeneic Stem Cell Transplantation with CD34+ Cell Selection

The success of allogeneic stem cell transplant is hampered by the development of acute and chronic graft-versus-host disease (GvHD) which has direct impact on treatment-related mortality and morbidity. As a result, T cell depletion through positive selection of CD34+ cells has emerged as a promising strategy to reduce acute and chronic GvHD in these patients.

In this review, we summarize the main characteristics of allogeneic stem cell transplant with CD34+ cell selection including risks of graft failure, GvHD, infection, organ toxicity, and long-term survival. Moreover, we highlight future strategies to improve the results of this platform and to consolidate its use in clinical practice.

Expanding Therapeutic Opportunities for Hematopoietic Stem Cell Transplantation: T Cell Depletion as a Model for the Targeted Allograft

Allogeneic hematopoietic cell transplantation is a fundamental part of the treatment of hematologic malignancies and marrow failure syndromes, but complications including graft-versus-host disease, prolonged immune deficiency and infection, and organ toxicities, as well as relapse, remain obstacles to improved overall survival. As the cellular characteristics of the allograft can exert significant impact on outcomes, the development of more strategically designed grafts represents a rich area for therapeutic intervention. We describe the use of ex vivo T cell–depleted grafts as a model for the targeted graft and review evolving knowledge and approaches for further refinement of allografts to improve patient outcomes.

Update on prevention of cytomegalovirus in hematopoietic cell transplantation

PURPOSE OF REVIEW

Cytomegalovirus infection (CMVi) has been the troll of allogeneic hematopoietic cell transplantation (allo-HCT). Over the last 4 decades various approaches have been adopted to minimize the burden from CMVi. There has been major advancement in the management of CMVi in HCT within the last few years that is poised to change the approaches employed in preventing and managing CMVi. This review will summarize recent advances and potential future development in the management of CMV in HCT.

RECENT FINDING

The major development has been the approval of letermovir for the prevention of CMVi in allo-HCT recipients. Also, with the potential availability of tests that can determine host CMV immunity a risk adapted approach to CMV prevention may become a possibility.

SUMMARY

The landscape of CMV prevention is about to change with the approval of a new anti-CMV antiviral that is safe and effective. However, the prophylaxis may lead to late onset CMVi in the context of ongoing risk factors after stopping prophylaxis and measures to counter this shifting epidemiology will need further research; such as extending the prophylaxis in high-risk patients vs. immunotherapy with vaccination and T-cell therapy.

Advances in Ex Vivo T Cell Depletion - Where Do We Stand?

Graft-versus-host (GVHD) is an important cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). As donor T cells are recognized as key drivers of GVHD, some approaches to prevent GVHD have focused on T cell depletion of the allograft. In this review we summarize methods and outcomes of ex vivo T cell depleted (TCD) HCT with a focus on CD34+ selection. This platform is efficacious in preventing acute and chronic GVHD across a wide range of hematologic malignancies, and with the exception of chronic myeloid leukemia, is not associated with adverse relapse or survival outcomes compared to conventional GVHD prophylaxis platforms. In retrospective comparisons recipients of CD34+ selected HCT have higher rates of GVHD-free relapse-free survival (GRFS) than conventional HCT counterparts. Although CD34+ selected allografts require myeloablative and antithymocyte-globulin based conditioning to support engraftment, abrogation of calcineurin inhibitors and methotrexate in this approach reduces its toxicity such that it can be considered in select older and more comorbid patients who could benefit from ablative HCT. A trial comparing GVHD prophylaxis regimens (BMT CTN 1301, NCT02345850) has completed accrual and will be the first to compare CD34+ selected HCT with conventional HCT in a randomized prospective setting. Its findings have potential to establish CD34+ selected HCT as a new standard-of-care platform for GVHD prevention.

Cytomegalovirus Infection in Allogeneic Hematopoietic Cell Transplantation Managed by the Preemptive Approach: Estimating the Impact on Healthcare Resource Utilization and Outcomes

We quantified cytomegalovirus (CMV) antiviral use and hospital length of stay (LOS) associated with CMV infection in a contemporary cohort of conventional (CONV) and CD34-selected (T cell-depleted) hematopoietic cell transplantation (HCT) recipients managed by preemptive therapy (PET) in a single US center. Adults who received first allogeneic HCT at Memorial Sloan Kettering Cancer Center from June 2010 through December 2014 were analyzed. Days on PET, number of readmissions, and readmission LOS by day 180 post-HCT were summarized. Estimated unit value (EUV) was defined as the expected number of PET days for a cohort of 100 HCT with characteristics as the analyzed cohort. Standardized incidence ratio was calculated as the ratio of observed outcomes of patients with CMV viremia over the outcomes of patients without CMV viremia. Of 318 patients, 88 received CONV and 230 CD34-selected HCT. Rates of CMV viremia were 26.3% for CONV and 41.9% for CD34-selected (P = .003). Among patients with viremia 68.2% CONV and 97.9% CD34-selected received PET. EUV for PET was 852 days and 2821 days for CONV and CD34-selected, respectively. The standardized incidence ratios for number of readmission and readmission LOS were 1.7 (95% confidence interval [CI], 1.4 to 2.1) and 1.2 (95% CI, 1.1 to 1.3), respectively, for CONV HCT and 1.7 (95% CI, 1.3 to 2.1) and 1.6 (95% CI, 1.5 to 1.7), respectively, for CD34-selected HCT. Overall survival was similar between patients with and without CMV viremia by HCT type. CMV end-organ disease was associated with lower overall survival only in CD34-selected HCT (P = .0007). CMV infection managed by PET requires substantial antiviral use and is associated with longer readmission LOS more, particularly among CD34-selected HCT.

Ex vivo and in vivo T cell-depleted allogeneic stem cell transplantation in patients with acute myeloid leukemia in first complete remission resulted in similar overall survival: on behalf of the ALWP of the EBMT and the MSKCC

Background

Graft-versus-host disease (GVHD) is one of the leading causes of non-relapse mortality and morbidity after allogeneic hematopoietic stem cell transplantation (allo-HCT).

Methods

We evaluated the outcomes of two well-established strategies used for GVHD prevention: in vivo T cell depletion using antithymocyte globulin (ATG) and ex vivo T cell depletion using a CD34-selected (CD34+) graft. A total of 525 adult patients (363 ATG, 162 CD34+) with intermediate or high-risk cytogenetics acute myeloid leukemia (AML) in first complete remission (CR1) were included. Patients underwent myeloablative allo-HCT using matched related or unrelated donors.

Results

Two-year overall survival estimate was 69.9% (95% CI, 58.5–69.4) in the ATG group and 67.6% (95% CI, 60.3–74.9) in the CD34+ group (p = 0.31). The cumulative incidence of grade II–IV acute GVHD and chronic GVHD was higher in the ATG cohort [HR 2.0 (95% CI 1.1–3.7), p = 0.02; HR 15.1 (95% CI 5.3–42.2), p < 0.0001]. Parameters associated with a lower GVHD-free relapse-free survival (GRFS) were ATG [HR 1.6 (95% CI 1.1–2.2), p = 0.006], adverse cytogenetic [HR 1.7 (95% CI 1.3–2.2), p = 0.0004], and the use of an unrelated donor [HR 1.4 (95% CI 1.0–1.9), p = 0.02]. There were no statistical differences between ATG and CD34+ in terms of relapse [HR 1.52 (95% CI 0.96–2.42), p = 0.07], non-relapse mortality [HR 0.96 (95% CI 0.54–1.74), p = 0.90], overall survival [HR 1.43 (95% CI 0.97–2.11), p = 0.07], and leukemia-free survival [HR 1.25 (95% CI 0.88–1.78), p = 0.21]. Significantly, more deaths related to infection occurred in the CD34+ group (16/52 vs. 19/112, p = 0.04).

Conclusions

These data suggest that both ex vivo CD34-selected and in vivo ATG T cell depletion are associated with a rather high OS and should be compared in a prospective randomized trial.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0668-3) contains supplementary material, which is available to authorized users.

Repurposing Nilotinib for Cytomegalovirus Infection Prophylaxis after Allogeneic Hematopoietic Stem Cell Transplantation: A Single-Arm, Phase II Trial

Platelet-derived growth factor receptor-alpha (PDGFRa) is a critical receptor for cytomegalovirus (CMV) entry into cells, leading to subsequent infection. This trial tested whether PDGFRa inhibition by nilotinib could prevent CMV infection in patients after allogeneic stem cell transplantation (allo-HSCT). Nilotinib (200 mg/day) was given continuously after engraftment, and plasma CMV DNA levels were monitored weekly. The primary endpoint was successful prophylaxis of CMV infection, defined as plasma CMV DNA copies less than 10,000 copies/mL, no anti-CMV treatment initiated, and no clinical CMV disease by day 100. All 37 enrolled recipients and their donors were CMV seropositive. Thirty patients received matched sibling transplants, 15 received nonmyeloablative conditioning regimens, and 15 received antithymocyte globulin as a part of graft-versus-host disease prophylaxis. The median interval from transplantation to nilotinib treatment was 23 days, and the median duration of administration was 76 days. None of the 31 assessable patients had nilotinib-associated grade 3/4 adverse events or nilotinib discontinuation. Twenty-five of 31 assessable patients (80.6%) fulfilled the predefined criteria for successful CMV prophylaxis, and none of them had clinical CMV disease. Only 1 of 6 failed patients developed CMV colitis. Nilotinib is well tolerated in allo-HSCT recipients, and its preliminary efficacy results suggest that blocking CMV entry to prevent CMV infection may warrant further exploration. (ClinicalTrials.gov identifier: NCT01252017.).

Cytomegalovirus resistance in CD34+ -selected hematopoietic cell transplant recipients

BACKGROUND

Cytomegalovirus (CMV) viremia after CD34+ -selected hematopoietic stem cell transplant (HCT) often requires prolonged antiviral therapy. We report rates and outcomes of resistant CMV in a contemporary cohort of CD34+ -selected HCT recipients managed preemptively.

METHODS

We retrospectively reviewed 220 consecutive, CMV-seropositive recipients (R+), who received CD34+ -selected HCT at Memorial Sloan Kettering Cancer Center between June 2010 and December 2014. Patients were monitored by quantitative CMV PCR and were treated preemptively. CMV resistance was tested by a genotypic assay.

RESULTS

One hundred and sixty-one (73%) patients developed CMV viremia and 47 (29% of viremic and 21% of total patients) had CMV resistance testing by one-year from HCT. CMV resistance was confirmed in 19 (12% of viremic and 9% of total) patients and was identified >3 months from HCT in 90% of patients. Twelve patients had mutations in UL97 only; the remaining 7 patients had mutations in UL54 only or UL54 and UL97. By 1 year from HCT, 11 of 19 (58%) patients with mutations had CMV end-organ disease. CMV-related mortality in patients with resistance was 42%.

CONCLUSIONS

Nine percent of CMV R+, CD34+ -selected HCT recipients had resistant CMV by 1 year from HCT. Of 19 patients with resistant CMV, 58% had CMV end-organ disease and 42% died of CMV. Effective strategies for CMV prevention and restoration of CMV immunity are needed for CD34+ -selected HCT.

The Impact of Toxicities on First-Year Outcomes after Ex Vivo CD34+-Selected Allogeneic Hematopoietic Cell Transplantation in Adults with Hematologic Malignancies

Factors that impact first-year morbidity and mortality in adults undergoing myeloablative allogeneic hematopoietic cell transplantation with ex vivo CD34⁺ selection have not been previously reported. We assessed all toxicities ≥ grade 3 from the start of conditioning to date of death, relapse, or last contact in 200 patients during the first year after transplantation, identifying 1885 individual toxicities among 17 organ-based toxicity groups. The most prevalent toxicities in the first year were of infectious, metabolic, hematologic, oral/gastrointestinal, hepatic, cardiac, and pulmonary etiologies. Renal complications were minimal. Grades II to IV and III and IV acute GVHD at day 100 were 11.5% and 3%, respectively. In separate multivariate models, cardiovascular, hematologic, hepatic, neurologic, pulmonary, and renal toxicities negatively impacted nonrelapse mortality (NRM) and overall survival during the first year. A higher-than-targeted busulfan level, patient cytomegalovirus seropositivity, and an Hematopoietic Cell Transplantation-Specific Comorbidity Index of ≥3 were associated with increased risk of NRM and all-cause death. Ex vivo CD34⁺ selection had a favorable 1-year OS of 75% and NRM of 17% and a low incidence of sinusoidal obstruction syndrome. These data establish a benchmark to focus efforts in reducing toxicity burden while improving patient outcomes.

Co-Infections by Double-Stranded DNA Viruses after Ex Vivo T Cell-Depleted, CD34+ Selected Hematopoietic Cell Transplantation

Recipients of ex vivo T cell-depleted (TCD) hematopoietic cell transplantation (HCT) are at risk of infection by double-stranded (ds) DNA viruses. We report rates of dsDNA viremia, end-organ disease (EOD), infection-related mortality, and overall survival (OS) in a contemporary cohort of adult TCD HCT recipients routinely monitored for cytomegalovirus (CMV), adenovirus (ADV), human herpesvirus 6 (HHV6), and Epstein-Barr virus (EBV). Healthcare utilization in the first 6 months post-HCT was compared between patients with dsDNA viremia versus no viremia. This was an observational study of adult patients with acute leukemia and myelodysplastic syndrome who received CD34⁺ selected, peripheral blood HCT at Memorial Sloan Kettering Cancer Center from March 2012 through December 2014. Patients were prospectively monitored by quantitative PCR assays for CMV, ADV, HHV6, and EBV in whole blood or plasma. The cumulative incidence of viremia(s) at day +180, EOD at 1 year, and OS at 1 year were estimated by the Kaplan-Meier method and compared by the log-rank test among patient with and without viremia/EOD. Standardized incidence ratios were used to compare overall length of hospital stay (LOS), number of readmissions after HCT, and length of readmissions through day +180. Of 156 patients, 96 (62%) were CMV recipient seropositive. Forty-two patients received grafts from matched related (27%), 86 from matched unrelated (55%), and 28 from mismatched (18%) donors. Overall, 132 patients (85%) had ≥1 viremia and 52 (33%) ≥2 viremias by day +180. The cumulative incidences for CMV, HHV6, ADV, and EBV viremia were 44%, 61%, 7%, and 16%, respectively, with median times of onset 28 days (interquartile range [IQR], 25 to 33), 33 days (IQR, 25 to 47), 60 days (IQR, 19 to 84), and 79 days (IQR, 54 to 106) post-HCT, respectively. Twenty-eight patients (18%) developed EOD by dsDNA viruses at 1 year post-HCT. Treatment for CMV accounted for 91% total antiviral treatment-days. Compared with patients with no viremia, patients with CMV viremia, HHV6 viremia, or ≥2 viremias experienced longer LOS (P <.001) and a higher number of readmissions (P <.001) by day +180. OS rate at 1 year was 79% and was similar between patients with or without dsDNA viremias. EOD was associated with lower 1-year OS rates (63.4%) versus without EOD (81.1%) (P = .02). Of 33 patients who died, 10 died due to infection, and 7 of these infection-related deaths were due to dsDNA viruses. Viremia by dsDNA viruses occurred in 85% of TCD HCT recipients by day +100 and 33% of patients experienced ≥2 viremias by day +180. CMV accounted for most antiviral use. CMV, HHV6, or ≥2 viremias were associated with more readmissions and longer LOS. One year OS rate was 78%. EOD by dsDNA viruses was associated with decreased 1-year OS. Infections by dsDNA viruses pose a substantial burden after TCD HCT.