BK Virus Hemorrhagic Cystitis Research Articles

Immune reconstitution in children after haploidentical haematopoietic stem cell transplantation.

Immune reconstitution (IR) kinetics of paediatric patients underwent haploidentical haematopoietic stem cell transplantation (HSCT) with post-transplant cyclophosphamide (PTCy) have not been extensively studied. We compared IR patterns of children receiving HSCT from haploidentical (n = 92) and HLA-matched donors (n = 36), and analysed risk factors for viral infection in these patients. We prospectively measured lymphocyte subset numbers before HSCT and at 1, 3, 6 and 12 months after HSCT. Blood cytomegalovirus (CMV), Epstein-Barr virus, adenovirus, BK virus (BKV) and urine adenovirus and BKV viral loads were measured at designated time points. The median numbers of total T and T helper cells at 1 month were significantly lower in the haploidentical group compared with the HLA-matched group. Haploidentical HSCT recipients had significantly lower median numbers of several T cell subsets and B cells for 1 year after HSCT. The median NK cell count of the haploidentical group was lower at 1 month. BKV haemorrhagic cystitis, blood CMV and urine adenovirus reactivation were more frequently found in the haploidentical group. Post-haploidentical HSCT patients receiving anti-T lymphocyte globulin (ATG) had significantly lower median numbers of total T cells (at 1 month) and T helper cells (at 6 and 12 months) and higher rate of blood BKV reactivation compared with those without ATG. Paediatric patients who undergo haploidentical HSCT with PTCy are likely to have delayed IR and an increased risk of viral reactivation/infection compared with HLA-matched HSCT. The addition of ATG to PTCy delayed T cell recovery and increased risk of BKV reactivation.

A Novel Prediction Model for BK Virus Associated Hemorrhagic Cystitis in Acute Leukemia Patients Following Allogenic Hematopoietic Cell Transplantation: A Retrospective Cohort Study

Introduction BK polyomavirus (BKV) has been associated with hemorrhagic cystitis (HC) after allogeneic hematopoietic cell transplantation (HSCT). BK virus hemorrhagic cystitis (BKHC) is associated with high morbidity and higher mortality. Previous studies have identified several risk factors associated with BKHC (Biol Blood Marrow Transplant, 2022). However, these results are contradictory among studies, and the potential mechanisms of BKHC are still unclear. Therefore, an accurate systematic evaluation method for screening high-risk populations before the onset of BKHC is highly necessary. This study was designed to establish an efficient prediction model for BKHC in acute leukemia patients following HSCT, thereby facilitating identification and early intervention in patients at high risk of BKHC. Methods In our retrospective study, a cohort of 789 acute leukemia patients following allogenic hematopoietic cell transplantation in 2019 was included and further divided into a BKHC group and a non-BKHC group. Among these patients, 80% were assigned to the derivation cohort, and 20% were assigned to the validation cohort. We first calculated the univariate association of each variable with the occurrence of BKHC. Second, the variables with p values less than 0.05 in the univariate analysis were further included as candidate predictors in the multivariate analysis using a backward stepwise logistic regression model. The variables that remained in the final model based on the outcomes of the multivariate analysis in the derivation cohort were identified as independent risk factors. The discrimination power of the model was assessed in both derivation and validation cohorts through ROC curve (AUC), calibration curve and decision curve analyses. Results Among 789 acute leukemia patients following allogenic hematopoietic cell transplantation, 171 patients were diagnosed with BKHC 14 days post transplantation according to the European Conference on Infections in Leukemia (ECIL) definition of BKHC. Patients with early-onset HC occurring within 14 days post transplantation were excluded from the BKHC group. The incidence rate of developing BKHC after allo-HSCT was 21.7%. The median time from transplantation to BKHC development was 30 days. Using multivariable logistic regression methods with stepwise variable selection, four highly significant independent risk factors for developing BKHC were identified: use of ATG during the transplantation regimen (p=0.048; odds ratio [OR], 2.32; 95% confidence interval [CI], 0.025-1.71), use of bone marrow blood and peripheral blood as sources of stem cells (p<0.001; odds ratio [OR], 0.25; 95% confidence interval [CI], 0.025-1.71), age less than 30 years old (p=0.02; odds ratio [OR], 1.74; 95% confidence interval [CI], 0.089-1.021) and absolute lymphocyte count at 14 days post-transplantation less than 0.035×10 9/L (p=0.02; odds ratio [OR], 2.59; 95% confidence interval [CI], 0.31-1.62). The area under the ROC curve (AUC) was 0.741 (95% confidence interval [CI], 0.694-0.789). According to the calibration plots, the model-predicted probabilities showed a good correlation with actual observed frequencies in both the derivation and validation cohorts. Decision curve analysis indicated that the clinical implementation of this model could benefit BKHC patients. A BKV-associated HC Risk Index (BHRI) was constructed according to the regression coefficients. The patient cohort was divided into a high-risk group and a low-risk group according to risk scores. Kaplan‒Meier estimations of the probabilities of BKHC were significantly different between the two risk groups. Conclusions Patients with BKHC after allo-HSCT usually have high morbidity and higher mortality. A novel prediction model, BHRI, was developed and validated, and this is the first straightforward scoring system designed to evaluate the probability of patients developing BKHC after receiving allo-HSCT to treat hematological malignancies. This model can be effectively utilized to help improve the prognosis of BKHC patients by accelerating the early identification of patients at a high risk of developing BKHC and contributing to the appropriate implementation of timely medical support.

Clinical Safety and Efficacy of Narsoplimab in Pediatric and Adult Patients with Transplant-Associated Thrombotic Microangiopathy: A Real-World Experience

Introduction Transplant-associated thrombotic microangiopathy (TA-TMA) is a severe complication occurring after hematopoietic stem cell transplantation (HSCT), often resulting in high morbidity and mortality. There are currently no approved treatments for TA-TMA, but complement inhibition is increasingly recognized as an active treatment option in this setting. Narsoplimab (OMS721) is a fully human IgG4 antibody that binds MASP-2, the effector enzyme of the lectin pathway of the complement system. A recent pivotal trial demonstrated the safety and efficacy of narsoplimab in patients with TA-TMA. We report the results of a real-world experience with narsoplimab in a series of pediatric and adult patients with TA-TMA. Material and methods The diagnosis of TA-TMA was based on the following criteria (Schoettler ML, et al. Transplant Cell Ther. 2023 Mar;29(3):151-163): anemia (failure to achieve transfusion independence, hemoglobin decline by ≥1 g/dL or new-onset transfusion dependence); thrombocytopenia (failure to achieve platelet engraftment, transfusion dependence, or ≥50% reduction in baseline platelet count after full platelet engraftment); elevated lactate dehydrogenase (LDH); decreased serum haptoglobin; schistocytes in the peripheral blood smear; hypertension; and proteinuria (≥1 mg/mg random urine protein-to-creatinine ratio [rUPCR]). A positive direct Coombs test was an exclusion criterion. Narsoplimab was administered intravenously at the dose of 4 mg/kg (max 370 mg) twice weekly for at least eight doses. Response criteria were defined by improvement in both laboratory TMA markers and any clinical benefit (Khaled SK, et al. J Clin Oncol. 2022 Aug;1;40(22):2447-2457). Results Fifteen patients with a median age of 61 years (range, 6 - 71), 11 adults and 4 pediatrics, were treated under a compassionate use program, after ethical committee approval, between January 2018 and April 2023. All patients had previously undergone allogeneic HSCT (Table 1). All patients presented at least 4 of the 6 criteria for TA-TMA diagnosis. Fourteen patients (93%) were defined as high-risk TA-TMA for the presence of the following criteria: LDH > 2 times the ULN, rUPCR ≥ 1 mg/mg, multiorgan dysfunction, concurrent acute GvHD ≥ grade 2, or infection. Time from transplant to TA-TMA was 161 days (range, 30 - 452). Before TA-TMA, all patients had acute GvHD with a median of 116 days (range, 21 - 405) after transplant. Severe infection had been documented in 10 patients (67%) after transplant. CMV reactivation and BK virus hemorrhagic cystitis occurred in 5 and 4 patients, respectively. Twelve patients (80%) were on calcineurin inhibitors at TA-TMA onset. Fourteen patients (93%) were transfusion dependent at baseline. Patients received a median of 11 (range, 8-34) doses of narsoplimab. All infusions were well-tolerated, and no narsoplimab-related adverse events were reported. Eleven patients responded to treatment (73%), based on the achievement of transfusion independence (10 patients) as well as on clinical and laboratory improvement, which occurred in all responders. Before and after narsoplimab, the median hemoglobin values were 9,1 g/dL (range, 7,7 - 12,3) and 10,35 g/dL (range, 9,2 - 12,4); the median platelet count was 25.000/mmc (range, 10.000 - 62.000) and 76.000/mmc (range 32.000 - 367.000); the median LDH values were 497 U/L (range 271 - 1201) and 224 U/L (range 184 - 393), respectively. The median time to response was 50 days (range, 9 - 105). One-hundred-day survival was 80% in the study population and 100% for responders (Figure 1). After treatment completion, TA-TMA never reoccurred. Three of the four patients who failed to respond, eventually died with laboratory and clinical evidence of persisting TA-TMA. Conclusion In this study of high-risk TA-TMA patients, the inhibition of the lectin pathway of complement activation with narsoplimab was shown to be not only an effective but also a remarkably safe treatment option with no evidence of an increased risk of infectious complications in both children and adults.

Incidence, risk factors and outcome of BK virus hemorrhagic cystitis following allogenic hematopoietic cell transplantation: a retrospective cohort study.

BK polyomavirus (BKPyV) can cause hemorrhagic cystitis (HC) after allogeneic hematopoietic cell transplantation (allo-HCT). Recent evaluation of BKPyV HC (BKHC) incidence and risk factors are scarce. We conducted a retrospective single-center study on a recent allo-HCT cohort over 3 years in a referral academic hospital for hematological malignancies. Primary objective was to determine BKHC incidence using competitive risk analysis. Secondary objectives were the identification of HC risk factors using Fine and Gray models and the evaluation of mortality. Among 409 allo-HCT recipients (median age 47 years), 41 developed BKHC after a median delay of 41 [32-55] days. Incidence density of BKHC was 2.4 [1.8-3.1] events per 100 days post-allo-HCT. The proportion of BKHC after adjustment for time-dependent competing risk was 9.5 [9.5-9.6]% at 100 days. BK viremia was detected in 63 versus 20% in tested patients with and without BKHC, respectively. After adjustment for confounders, myeloablative conditioning regimen with and without cyclophosphamide and CMV seropositivity were independently associated with BKHC. Post-transplantation cyclophosphamide was not associated with BKHC. BKHC resolved in 90% of the patients. No difference in mortality was found between patients with or without BKHC. In parallel to the recent evolution of allo-HCT protocols, BKHC remains a frequent complication following allo-HCT.

Acute GVHD, BK virus hemorrhagic cystitis and age are risk factors for transplant-associated thrombotic microangiopathy in adults

AbstractHematopoietic cell transplantation–associated thrombotic microangiopathy (TMA) is a complication associated with higher nonrelapse mortality (NRM) in patients who undergo allogeneic transplant (HCT). Current classification criteria are not generally agreed on or validated, and the presence of confounding factors after transplant contribute to underdiagnosis or delayed diagnosis of TMA. We studied risk factors, incidence, and biomarkers of TMA in 119 adult allogeneic HCT recipients. Twenty-seven patients developed a clinically actionable phenotype of TMA (CA-TMA) and the incidence of CA-TMA was 22% by day 180. Among the 27 patients who developed CA-TMA, 10 developed it before the onset of acute graft-versus-host disease (aGVHD), and 17 patients developed it after the onset of aGVHD. We report for the first time that age >50 years, BK hemorrhagic cystitis, and other viral infections (CMV, HHV-6, or adenovirus) are risk factors for adult CA-TMA. Even after adjustment for aGVHD, CA-TMA was independently associated with significantly higher NRM. These data illustrate relationships between CA-TMA and aGVHD, describe new risk factors for CA-TMA and emphasizes the need to develop validated set of criteria for timely diagnosis.

Intravesical alprostadil as a promising agent in BK virus-associated hemorrhagic cystitis: A report of a refractory case.

Allogeneic stem cell transplant recipients are at risk of BK virus-associated hemorrhagic cystitis. This condition causes a significant morbidity and worsens clinical outcomes. The standard cares for BK virus-associated hemorrhagic cystitis are saline irrigation and forced diuresis. Notably, several beneficial roles are proposed for antiviral and anti-inflammatory agents against BK virus-associated hemorrhagic cystitis. However, cases who are at risk of cystectomy remain refractory. Herein, we present a 13-year-old boy with severe hematuria by passing two months from his allogeneic stem cell transplantation. The laboratory work up showed high BK viremia >1.1 × 108 copies/ml in this case's urine sample. The patient was treated with antiviral agents in combination with supportive care. Moreover, intravesical alum was administered, but no clinical benefits were achieved. Finally, intravesical alprostadil was prepared under the supervision of a pediatric clinical pharmacist. In this regard, an alprostadil solution was prepared by constitution of 250 μg alprostadil in 50 mL saline. After administrating the first dose of intravesical alprostadil, an acceptable clinical response was observed, and hematuria stopped. Of note, alprostadil induces platelet aggregation and vasoconstriction. Thus, bleeding can be controlled after the administration of intravesical alprostadil. This strategy may be associated with several side effects including bladder spasm. This study is the first report describing the special role of intravesical alprostadil in refractory cases of BK virus-associated hemorrhagic cystitis. In such refractory cases, clinicians can use intravesical alprostadil rather than invasive therapies in the treatment of BK virus-hemorrhagic cystitis.

Beyond antivirals: virus-specific T-cell immunotherapy for BK virus haemorrhagic cystitis and JC virus progressive multifocal leukoencephalopathy.

The clinical manifestations of the polyomaviruses BK and JC in immunocompromised patients include BK virus (BKV) induced haemorrhagic cystitis and nephropathy, and JC virus (JCV) associated progressive multifocal leukoencephalopathy (PML) and are typically a consequence of impaired adaptive immunity in the host. To date, little clinical success has been achieved with antiviral agents or other drug therapies to treat these conditions. Here we review the methods and outcomes of the most recent clinical studies utilising adoptive immunotherapy with BK and/or JC virus-specific T-cells (VST) as either prophylaxis or treatment alternatives. In the last 12-18 months, several clinical trials have been published in the post-haemopoietic stem cell transplant (HSCT) setting showing good clinical success with the use of VST for treatment of BK viremia ± haemorrhagic cystitis. Between 82 and 100% clinical response has been observed in haemorrhagic cystitis using either third-party or donor-derived VST. The therapy was well tolerated with few cases of graft versus host disease in HSCT recipients, but immune mediated renal allograft loss was observed in one renal transplant recipient. Studies using BKV/JCV VST to treat PML are hindered by few patients who are sufficiently stable to receive VST. In a condition that otherwise carries such poor prognosis, VST were associated with clearance of JC virus, clinical and radiological improvement in some patients. Immune reconstitution inflammatory syndrome was a noted adverse event. Restoration of BK and JC virus immunity using VST immunotherapy has shown good clinical outcomes in BKV associated infections. Further evaluation with the administration of VST earlier in the course of disease is warranted for the treatment of BKV associated nephropathy in renal allograft and in JCV PML. In both indications, larger cohorts and standardisation of dosing and outcome measures would be of benefit.

The Risk Of BK Virus Haemorrhagic Cystitis After Allogeneic Hematopoietic Stem Cell Transplantation Is Increased With Myeloablative Conditioning, CMV Viremia and Acute Gvhd

IntroductionBK virus associated hemorrhagic cystitis (HC) is a common complication post allogeneic hematopoietic cell transplantation (HSCT). A number of retrospective studies have suggested a variety of risk factors for HC following HSCT including busulfan-containing myeloablative conditioning regimens, unrelated donors, and the occurrence of graft versus host disease (GVHD). However, these risk factors were not observed consistently and have led us to review the incidence and risk factors for BK-HC confirmed by microbiologic test at our institution. Methods and patientsWe retrospectively reviewed 339 patients who received HSCT between 2009 and 2012 at the Princess Margaret Cancer Centre, Toronto Canada. The diagnosis of BK-HC was based on clinical features, urinalysis and detection of BK virus by urine PCR. The cumulative incidence of BK-HC was calculated considering competing risks and Gray's method was used for univariable analysis. To confirm the results of the univariable analysis, we conducted a multivariable analysis using the Fine-Gray method and EZR software. ResultsOut of 339 patients, 79 patients (23.3%) developed BK-HC. The median onset was 47 days (range 16-749) after HSCT. The median time to resolution of symptoms was 21 days (range 4-260). The clinical grades were as follows: grade 1 (n=14, 17.9%), 2 (n=34, 43.0%), 3 (n=22, 27.8%) and 4 (n=8, 10.1%). Sixty-two patients (83.7%) out of 74 had urine BK virus PCR testing which showed a high titer of BK virus PCR (mean 2.56x1010 (SD 7.41x1010) and median 6.19x109). The cumulative incidence of BK-HC at 2 years was 24.0% (95% CI, 19.4-28.9). There was no difference in transplant characteristics between the HC and non-HC groups, in terms of age, gender, gender match, diagnosis, HLA match and donor type, stem cell source, T-cell depletion, GVHD prophylaxis and CMV serostatus. However there was a higher incidence of BK-HC in the group of patients receiving myeloablative conditioning (62/208, 29.8%) vs (17/132, 12.9%, p<0.001) in the reduced intensity conditioning group. In the univariable model three risk factors for BK-HC were identified: myeloablative conditioning (31.2% in myeloablative vs 12.4% in reduced intensity; p<0.001), HLA mismatch (34.9% in mismatched vs 22.0% in matched, p=0.027), CMV viremia (28.6% in CMV+ vs 19.1% in CMV-; p=0.023) and acute GVHD (30.2% in aGVHD vs 12.0% in without aGVHD; p<0.001). Unrelated donor or T-cell depletion did not increase the risk of HC in univariable analysis. Multivariable analysis confirmed that these 3 factors were independent risk factors for BK-HC: myeloablative conditioning (p<0.001; HR 2.38, 95% CI, 1.35-4.17), CMV viremia (p=0.012; HR 1.77, 95% CI, 1.10-2.83) and aGVHD (p<0.001; HR 2.26, 95% CI, 1.23-4.13). HLA mismatch was not an independent risk factor. The 2-year overall survival (OS) of the study cohort was 51.6%. The development of BK-HC did not affect transplant outcomes with respect to OS (p=0.446). We observed a higher incidence of 1-year non-relapse mortality (NRM) in the BK-HC group 39.7% vs 24.2% in the non HC group, but this was not confirmed in the multivariable analysis. ConclusionSymptomatic BK-HC is a frequent complications following HSCT with a 2-year cumulative incidence of 24.0%. Three risk factors for BK-HC were identified including myeloablative conditioning, CMV viremia and aGVHD. While this infection did not adversely impact survival, it is associated with significant morbidity and constitutes an unmet need given the lack of effective therapy. Disclosures:No relevant conflicts of interest to declare.

Risk factors of BK viral hemorrhagic cystitis in allogenic hematopoietic stem cell transplantation.

Reactivation of BK virus (BKV) can occur during intensive immunosuppression such as in allogenic hematopoietic stem cell transplant (AHSCT) recipients for whom a systematic PCR urine test for BKV will be positive in 50% to 100% of patients. Only 5% to 40% will develop BKV hemorrhagic cystitis (HC). Thus, BKV PCR testing is useful to confirm a diagnosis of BKV-HC but not to predict its occurrence. The aim of this retrospective study was to ascertain the risk factors of developing BKV HC, mostly in patients receiving posttransplant cyclophosphamide. The study looked at data from Grenoble Alpes University Hospital included in the national retrospective register ProMISe, administered by the "Société Francophone de Greffe de Moelle et de Thérapie Cellulaire". Urine BKV PCR was performed when patients presented grade≥2 hematuria with clinical symptoms of cystitis. BKV-HC was defined as an association of clinical symptoms of cystitis, grade≥2 hematuria and BKV viruria>7 log10 copies/ml. From January 2014 to January 2018, 168 AHSCTs were considered for analysis, of which 43 (25.6%) developed BKV-HC and 44.9% of the subgroup that received posttransplant cyclophosphamide. After logistic regression, the risk factors associated with BKV-HC were reduced to posttransplantation exposure to cyclophosphamide (OR 4.25, [1.66; 10.87], P=.02), age<40y (OR 3.85 [1.51; 9.80], P=.005) and corticosteroid therapy (OR 3.86, [1.59; 9.36], P=.003). Exposure to cyclophosphamide, younger age (<40) and corticosteroid therapy are potential risk factors for BKV-HC.

531 - BMT CTN 1803: Haploidentical Natural Killer Cells (K-NK002) to Prevent Post-Transplant Relapse in AML and MDS (NK-REALM)

Background and Rationale: Relapse remains the leading cause of treatment failure for patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) undergoing allogeneic bone marrow transplantation (BMT). Although the risk depends on parameters such as age and conditioning intensity, relapse is experienced by 30-50% of patients after conventional BMT in high-risk AML/MDS. Initial safety and post-BMT relapse risk reduction results were reported from a phase I study of haploidentical (haplo) donor-derived natural killer (NK) cells expanded ex vivo on feeder cells expressing IL-21 and 4-1BBL (FC21-NK) in conjunction with haploBMT. Of 13 patients with high-risk myeloid malignancies treated with FC21-NK cells, no infusion reactions or dose-limiting toxicities occurred and only 1 patient, treated at the lowest dose of 1×105 cells/kg, relapsed (Ciurea, Blood, 2017). This experience supports investigation of K-NK002, a product derived from haploidentical donor NK cells and expanded ex vivo in a feeder cell-free system using plasma membrane (PM21) particles bearing membrane-bound IL-21 and 4-1BBL. We used contemporary data from the Center for International Blood and Marrow Transplant Research registry to determine baseline relapse rates that informed the statistical design. K-NK002 will be given in the peri-transplant period to test the hypothesis that haploidentical NK cells can mediate an effective anti-leukemia response. Trial Design and Methods: BMT CTN 1803 is a phase II, single-arm, open-label, multicenter trial designed to investigate the safety and efficacy of K-NK002 for the treatment of patients with high-risk AML or MDS undergoing haploBMT (NCT04395092). An initial 6 patient safety run-in phase will precede enrollment into the full study of approximately 60 patients. Major inclusion criteria of patients and donors are listed in Table 1. Production of the haploidentical donor NK-cells is completed prior to the planned haploBMT. BMT conditioning will consist of 140 mg/m2 (100 mg/m2 for patients ≥60 years old) melphalan on Day -7; 40 mg/m2 fludarabine on Days -7, -6, -5, and -4; and 2 Gy of total body irradiation on Day -3. Donor bone marrow will be harvested and given on Day 0. Three doses of K-NK002 (1×108 NK cells/kg) will be administered IV on Days -2, +7, and +28, relative to the haploBMT. Graft-versus-host disease (GVHD) prophylaxis consists of post-transplantation cyclophosphamide with tacrolimus and mycophenolate mofetil. The primary endpoint is cumulative incidence of relapse at 1 year post haploBMT in patients receiving at least 1 infusion of K-NK002. Secondary endpoints are safety and tolerability of K-NK002; overall survival; non-relapse mortality; relapse-free survival; GVHD-free survival; cumulative incidence of acute GVHD and chronic GVHD; hematologic recovery; donor-cell engraftment; primary and secondary graft failure; overall incidence of toxicity; and cumulative incidence of infections including cytomegalovirus re-activation and symptomatic BK virus hemorrhagic cystitis. Exploratory endpoints are systemic immunosuppression-free survival; immune reconstitution at Days 28, 100, and 365 post haploBMT; proportion of patients with detectable minimal residual disease at Days 28 and 100 post haploBMT; feasibility of administering the planned K-NK002 doses; and impact of NK-cell alloreactivity on relapse and survival. Download : Download high-res image (319KB) Download : Download full-size image Disclosures Bejanyan: Kiadis Pharma: Membership on an entity’s Board of Directors or advisory committees. Devine: Magenta Therapeutics: Consultancy. Luznik: WindMil Therapeutics: Patents & Royalties: Patent holder; Genentech: Research Funding; Merck: Research Funding, Speakers Bureau; AbbVie: Consultancy. Sandler: Kiadis Pharma: Current Employment. Krakow: HighPass Bio: Research Funding. Fitzgerald: Kiadis Pharma: Current Employment. Tracey: Kiadis Pharma: Current Employment. Champlin: DKMS America: Membership on an entity’s Board of Directors or advisory committees; Takeda: Patents & Royalties; Actinium: Consultancy; Johnson and Johnson: Consultancy; Cytonus: Consultancy; Omeros: Consultancy; Genzyme: Speakers Bureau.

BMT CTN 1803: Haploidentical Natural Killer Cells (K-NK002) to Prevent Post-Transplant Relapse in AML and MDS (NK-REALM)

Background and Rationale: Relapse remains the leading cause of treatment failure for patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) undergoing allogeneic bone marrow transplantation (BMT). Although the risk depends on parameters such as age and conditioning intensity, relapse is experienced by 30-50% of patients after conventional BMT in high-risk AML/MDS. Initial safety and post-BMT relapse risk reduction results were reported from a phase I study of haploidentical (haplo) donor-derived natural killer (NK) cells expanded ex vivo on feeder cells expressing IL-21 and 4-1BBL (FC21-NK) in conjunction with haploBMT. Of 13 patients with high-risk myeloid malignancies treated with FC21-NK cells, no infusion reactions or dose-limiting toxicities occurred and only 1 patient, treated at the lowest dose of 1×105 cells/kg, relapsed (Ciurea, Blood, 2017). This experience supports investigation of K-NK002, a product derived from haploidentical donor NK cells and expanded ex vivo in a feeder cell-free system using plasma membrane (PM21) particles bearing membrane-bound IL-21 and 4-1BBL. We used contemporary data from the Center for International Blood and Marrow Transplant Research registry to determine baseline relapse rates that informed the statistical design. K-NK002 will be given in the peri-transplant period to test the hypothesis that haploidentical NK cells can mediate an effective anti-leukemia response. Trial Design and Methods: BMT CTN 1803 is a phase II, single-arm, open-label, multicenter trial designed to investigate the safety and efficacy of K-NK002 for the treatment of patients with high-risk AML or MDS undergoing haploBMT (NCT04395092). An initial 6 patient safety run-in phase will precede enrollment into the full study of approximately 60 patients. Major inclusion criteria of patients and donors are listed in Table 1. Production of the haploidentical donor NK-cells is completed prior to the planned haploBMT. BMT conditioning will consist of 140 mg/m2 (100 mg/m2 for patients ≥60 years old) melphalan on Day -7; 40 mg/m2 fludarabine on Days -7, -6, -5, and -4; and 2 Gy of total body irradiation on Day -3. Donor bone marrow will be harvested and given on Day 0. Three doses of K-NK002 (1×108 NK cells/kg) will be administered IV on Days -2, +7, and +28, relative to the haploBMT. Graft-versus-host disease (GVHD) prophylaxis consists of post-transplantation cyclophosphamide with tacrolimus and mycophenolate mofetil. The primary endpoint is cumulative incidence of relapse at 1 year post haploBMT in patients receiving at least 1 infusion of K-NK002. Secondary endpoints are safety and tolerability of K-NK002; overall survival; non-relapse mortality; relapse-free survival; GVHD-free survival; cumulative incidence of acute GVHD and chronic GVHD; hematologic recovery; donor-cell engraftment; primary and secondary graft failure; overall incidence of toxicity; and cumulative incidence of infections including cytomegalovirus re-activation and symptomatic BK virus hemorrhagic cystitis. Exploratory endpoints are systemic immunosuppression-free survival; immune reconstitution at Days 28, 100, and 365 post haploBMT; proportion of patients with detectable minimal residual disease at Days 28 and 100 post haploBMT; feasibility of administering the planned K-NK002 doses; and impact of NK-cell alloreactivity on relapse and survival. Disclosures Bejanyan: Kiadis Pharma: Membership on an entity's Board of Directors or advisory committees. Devine:Magenta Therapeutics: Consultancy. Luznik:WindMil Therapeutics: Patents &amp; Royalties: Patent holder; Genentech: Research Funding; Merck: Research Funding, Speakers Bureau; AbbVie: Consultancy. Sandler:Kiadis Pharma: Current Employment. Krakow:HighPass Bio: Research Funding. Fitzgerald:Kiadis Pharma: Current Employment. Tracey:Kiadis Pharma: Current Employment. Champlin:DKMS America: Membership on an entity's Board of Directors or advisory committees; Takeda: Patents &amp; Royalties; Actinium: Consultancy; Johnson and Johnson: Consultancy; Cytonus: Consultancy; Omeros: Consultancy; Genzyme: Speakers Bureau.

BMT CTN 1803: Trial to Investigate If Haploidentical Natural Killer Cells (CSTD002) Prevent Post-Transplant Relapse in AML and MDS (NK-REALM)

Background and Rationale Relapse remains the leading cause of treatment failure for 30–50% of patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) undergoing allogeneic blood or marrow transplantation (BMT). Safety and relapse risk reduction with an ex vivo-expanded, donor-derived, haploidentical (haplo) natural killer (NK)-cell infusion in conjunction with haploBMT were reported by investigators at MD Anderson Cancer Center in a phase I study (Ciurea, Blood 2017). These data support investigation of CSTD002, haplo NK cells expanded ex vivo using plasma membrane nanoparticles bearing membrane-bound IL-21 and 4-1BBL. This study represents a public–private partnership between the sponsor (Kiadis Pharma) and the Blood and Marrow Transplant Clinical Trials Network (BMT CTN), leveraging existing National Institutes of Health-supported clinical trials infrastructure to conduct the trial. Trial Design and Methods BMT CTN 1803 is a phase II, single-arm, open-label, multicenter trial designed to investigate the safety and efficacy of CSTD002 for the treatment of patients with high-risk AML or MDS undergoing haploBMT. An initial safety run-in phase will precede enrollment into the full study of approximately 60 patients. Donor peripheral blood will be drawn to start the NK-cell expansion approx. 5 weeks before the planned haploBMT. Patients will receive melphalan 140 mg/m2 IV (100 mg/m2 for patients ≥60 years old) on Day -7; fludarabine 40 mg/m2 IV on Days -7, -6, -5, and -4; and 2 Gy of total body irradiation on Day -3. Donor bone marrow will be harvested and given on Day 0. Three doses of CSTD002 will be administered IV on Days -2, +7, and +28, relative to the haploBMT. The recommended dose of CSTD002 for administration will be formulated at 1 × 108 NK cells/kg of recipient body weight. Graft-versus-host disease (GVHD) prophylaxis is post-transplantation cyclophosphamide with tacrolimus and mycophenolate mofetil. The primary endpoint is cumulative incidence of relapse at 1 year post haploBMT in patients receiving at least 1 infusion of CSTD002. Secondary endpoints are safety and tolerability of CSTD002; overall survival; non-relapse mortality; relapse-free survival; GVHD-free survival; cumulative incidence of acute GVHD and chronic GVHD; hematologic recovery; donor-cell engraftment; primary and secondary graft failure; overall incidence of toxicity; and cumulative incidence of infections including cytomegalovirus re-activation and symptomatic BK virus hemorrhagic cystitis. Exploratory endpoints are systemic immunosuppression-free survival; immune reconstitution at Days 28, 100, and 365 post haploBMT; proportion of patients with detectable minimal residual disease at Days 28 and 100 post haploBMT; feasibility of administering the planned CSTD002 doses; and impact of NK-cell alloreactivity on relapse and survival.

Intravesicular Cidofovir in the Treatment of BK Virus-Associated Hemorrhagic Cystitis Following Hematopoietic Stem Cell Transplantation.

Background: BK virus hemorrhagic cystitis (BKV-HC) is a common complication following hematopoietic stem cell transplant (HSCT); optimal management remains uncertain. Supportive care (bladder irrigation and blood transfusions) and intravenous and intravesicular cidofovir have all been used with varying success. Objective: The purpose of this study was to determine the safety and effectiveness of intravesicular cidofovir for BKV-HC following HSCT. Methods: A retrospective analysis of all HSCT patients with BKV-HC prescribed intravesicular cidofovir from 2012 to 2017. Results: 33 patients were treated for BKV-HC. The median age was 50 years (range 23-73), and 18 (55%) were male. The median HC symptom severity was 2, with a median BK urine viral load pretreatment of 100,000,000 IU/mL. Patients received a median of 2 intravesicular treatments (range 1-7) at a dosage of 5 mg/kg per instillation. In all, 19 (59%) patients demonstrated complete clinical resolution of symptoms; 9 (28%) had a partial response; and 4 (13%) had no change in symptoms. Patients with a high pretreatment BK viral load (>100 million) and high HC grade (2-4) had a lower frequency of complete remission. The main side effect of intravesicular instillation was severe bladder spasms in 4 patients (12%). Conclusion and Relevance: This is the largest study of intravesicular cidofovir treatment of BKV HC reported to date; 88% of patients with BVK-HC achieved clinical improvement of symptoms with minimal side effects. Clinical trials of intravesicular cidofovir could provide further evidence for this treatment for BKV-HC.

BMT CTN 1803: Haploidentical Natural Killer Cells (CSTD002) to Prevent Post-Transplant Relapse in AML and MDS (NK-REALM)

Background and Rationale: Relapse remains the leading cause of treatment failure for patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) undergoing allogeneic blood or marrow transplantation (BMT). Although relapse rates vary based on patient population, age, and conditioning intensity, relapse is experienced in at least 30-50% after conventional BMT in high-risk AML/MDS. Initial safety and post-BMT relapse risk reduction results are reported by investigators at MD Anderson Cancer Center in a phase I study of ex vivo-expanded, donor-derived, haploidentical natural killer (NK)-cell infusion in conjunction with haploBMT. Of 13 patients with high-risk myeloid malignancies treated with NK cells, no infusion reactions or dose-limiting toxicities occurred and only 1 patient, treated at the lowest dose of 1×105 cells/kg, relapsed (Ciurea, Blood 2017). This experience supports investigation of CSTD002, a product derived from haploidentical donor NK cells and expanded ex vivo using plasma membrane (PM21) nanoparticles bearing membrane-bound IL-21 and 4-1BBL. This study represents a public-private partnership between the sponsor (Kiadis Pharma) and the Blood and Marrow Transplant Clinical Trials Network (BMT CTN), leveraging existing National Institutes of Health-supported clinical trials infrastructure to conduct a complex cellular immunotherapy trial. We used contemporary, unpublished data from the Center for International Blood and Marrow Transplant Research registry to determine baseline relapse rates that informed the statistical design. Doses of NK cells expanded by a novel method and exceeding those previously achieved in most published studies will be given in the peri-transplant period to test the hypothesis that haploidentical NK cells can mediate an effective anti-leukemia response. Trial Design and Methods: BMT CTN 1803 is a phase II, single-arm, open-label, multicenter trial designed to investigate the safety and efficacy of CSTD002 for the treatment of patients with high-risk AML or MDS undergoing haploBMT. An initial safety run-in phase will precede enrollment into the full study of approximately 60 patients. Major inclusion criteria of patients and donors are listed in the Table. Peripheral blood will be drawn from the donor to start the NK-cell expansion approximately 5 weeks before the planned haploBMT. Patients will receive intravenous (IV) melphalan 140 mg/m2 (100 mg/m2 for patients ≥60 years old) on Day -7; fludarabine 40 mg/m2 IV on Days -7, -6, -5, and -4; and 2 Gy of total body irradiation on Day -3. Donor bone marrow will be harvested and given on Day 0. Three doses of CSTD002 will be administered IV on Days -2, +7, and +28, relative to the haploBMT. The recommended dose of CSTD002 for administration will be formulated at 1×108 NK cells/kg of recipient body weight. Graft-versus-host disease (GVHD) prophylaxis is post-transplantation cyclophosphamide with tacrolimus and mycophenolate mofetil. The primary endpoint is cumulative incidence of relapse at 1 year post haploBMT in patients receiving at least 1 infusion of CSTD002. Secondary endpoints are safety and tolerability of CSTD002; overall survival; non-relapse mortality; relapse-free survival; GVHD-free survival; cumulative incidence of acute GVHD and chronic GVHD; hematologic recovery; donor-cell engraftment; primary and secondary graft failure; overall incidence of toxicity; and cumulative incidence of infections including cytomegalovirus re-activation and symptomatic BK virus hemorrhagic cystitis. Exploratory endpoints are systemic immunosuppression-free survival; immune reconstitution at Days 28, 100, and 365 post haploBMT; proportion of patients with detectable minimal residual disease at Days 28 and 100 post haploBMT; feasibility of administering the planned CSTD002 doses; and impact of NK-cell alloreactivity on relapse and survival. Disclosures Vasu: Boehringer Ingelheim: Other: Travel support; Seattle Genetics: Other: Clinical trial support. Bejanyan:Kiadis Pharma: Other: advisory board. Devine:Kiadis Pharma: Other: Protocol development (via institution); Magenta Therapeutics: Other: Travel support for advisory board; My employer (National Marrow Donor Program) has equity interest in Magenta; Bristol Myers: Other: Grant for monitoring support &amp; travel support. Krakow:Bellicum Pharmaceuticals: Research Funding; Highpass Bio: Research Funding; Magnolia Innovations: Other: Personal fees. Logan:Eisai: Other: Personal fees; Astellas: Other: Grant; Kiadis (formerly Cytosen): Other: Grant; Novartis: Other: Personal fees; Kite: Other: Grant. Luznik:Merck: Research Funding, Speakers Bureau; Genentech: Research Funding; AbbVie: Consultancy; WindMiL Therapeutics: Patents &amp; Royalties: Patent holder. Barrett:Kiadis Pharma (formerly Cytosen): Other: Personal fees; Biologics Consulting Company: Other: Personal fees. Shan:Kiadis Pharma (formerly Cytosen): Employment. Champlin:Actinium: Consultancy; Johnson and Johnson: Consultancy; Sanofi-Genzyme: Research Funding.

Administration of Third-Party Virus-Specific T-Cells (VST) at the Time of Initial Therapy for Infection after Haemopoietic Stem Cell Transplant Is Safe and Associated with Favourable Clinical Outcomes (the R3ACT-Quickly trial)

Background Administration of partially HLA-matched third party virus-specific T cells (VST) from a cryopreserved cell bank is safe and effective after failure of standard antiviral therapy to resolve viral infection occurring after allogeneic stem cell transplantation (HSCT). Aim In this phase I trial, we assessed the safety and efficacy of administering partially HLA-matched third party VST at the time of initial antiviral therapy following HSCT rather than waiting for failure of at least two weeks of standard antiviral treatment. Methods A cryopreserved cell bank of VST directed at cytomegalovirus (CMV), Epstein Barr virus (EBV) or adenovirus (Adv) was established using G-CSF mobilised peripheral blood from healthy stem cell donors. After stimulation with peptide mixes, VST were selected by expression of CD137+ cells and cultured with cytokines. HSCT recipients were treated with up to 4 doses of 2x107 of VST/m2, the first commencing within 7 days of initial antiviral treatment for viral reactivation. Results A total of 188 doses of VST were manufactured from 7 donors with 12 product manufacturing runs (CMV n=3, EBV n=4 and Adv n=5). Median virus specificity was 75% for CMV, 83% for EBV and 37% for Adv. Thirty HSCT recipients were treated with VST a median of 55 days post-transplant. Data from 25 patients treated for initial viral reactivation were available for analysis (CMV n=22, EBV n=2, Adv n=1). Median age was 58 years (0-71). Patients underwent transplant for myeloid malignancies (n=16), lymphoid malignancies (n=5) and non-malignant conditions (n=4). Patients with malignant disease were transplanted in CR1 (n=8), CR2 (n=3), &amp;gt;CR2 (n=3) or with active disease (n=7). Conditioning was myeloablative in 11 patients and reduced intensity in 14 patients. Donors were matched unrelated (n=20), haploidentical (n=4) or siblings (n=1). 21 patients received some form of T cell depletion (most commonly pre-transplant thymoglobuline in vivo). All patients received VST within 7 days of commencing initial antiviral therapy. 18 patients received a single VST infusion, 6 received 2 and 1 received 4 VST infusions. There were 3 mild infusion related adverse events (vomiting, hypertension, fever). 3 patients had aGVHD pre-infusion (2 grade 1 skin, 1 grade 3 GI). Two patients died of acute GVHD (1 patient with resolved grade 3 GI GVHD pre-VST infusion developed grade 4 GI GVHD 89 days post- infusion as immunosuppression was weaned; the other patient developed de novo liver and GI GVHD 30 days post infusion in the context of a rapid wean in immunosuppression for severe BK virus haemorrhagic cystitis). 2 patients developed de novo grade 1 GVHD post-infusion. 2 patients developed mild limited cGVHD and 1 patient developed extensive cGVHD after VST infusion. 23/25 patients (92%) had complete viral clearance of the infection for which VST were given, 2 had a partial viral response. Median time to best viral response was 20 days. There were 5 deaths (refractory aGVHD in 2 patients, pulmonary VOD/CMV pneumonitis, disease relapse, and sepsis/aspiration pneumonia). 4 of 25 patients died within 12 months of transplant for a 1 year NRM of 12%. At a median follow up of 431 days (112-1391) post-transplant, 20 of 25 patients (80%) remain alive (Figure 1). Conclusion Infusion of third party partially HLA-matched donor-derived VST at the time of first antiviral treatment for CMV, EBV and Adv post HSCT is associated with minimal infusion toxicity, a low rate of moderate to severe GVHD and complete viral clearance in 92% of recipients. Overall survival in this group of high-risk patients requiring treatment for viral reactivation after HSCT is high. A randomised trial will be performed to determine whether administration of third-party VST in addition to standard anti-viral treatment improves transplant outcomes. Figure 1 Disclosures Gottlieb: Haemalogix P/L: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy; Gilead: Consultancy; AbbVie: Consultancy; University of Sydney: Employment; Merck: Consultancy. Ritchie:Amgen: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy; BMS: Research Funding; Takeda: Research Funding; Beigene: Research Funding; Imago: Research Funding; Novartis: Honoraria; Sanofi: Honoraria.

Post Transplantation Cyclophosphamide (PTCY) Is Associated with Increased Risk of BK Virus-Associated Hemorrhagic Cystitis (BKHC) in Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplant (HSCT).

Introduction BK virus hemorrhagic cystitis is a well-recognized complication in patients undergoing allogeneic HSCT and is associated with significant morbidity. PTCY has been used for GVHD prophylaxis in patients undergoing haploidentical or mismatched unrelated donor HSCT. We hypothesized that PTCY is associated with increased incidence of HC associated with BK virus. Objectives • To identify the risk factors for developing BKHC in allogeneic HSCT • To assess the effect of PTCY in development of BKHC in patients with myeloablative (MA) regimen containing total body irradiation (TBI) • To evaluate the risk of concurrent CMV infection and BKHC in allogeneic HSCT with MA conditioning regimen Methods We identified 116 consecutive patients who underwent allogeneic HSCT at our institution between January 2015 and July 2018. The MA regimen (n=42) consisted of fludarabine 50 mg/m2/day IV for 5 days and busulfan 3.2 mg/kg/day IV for 4 days with or without TBI of 200 cGy/day for 2 days (FBT or FB4). The reduced intensity conditioning (RIC) regimen (n=74) consisted of fludarabine 30 mg/m2/day IV for 5 days and busulfan 3.2 mg/kg/day IV for 2 days (FB2). In terms of GVHD prophylaxis all recipients except those undergoing haploidentical and mismatched unrelated transplant received Thymoglobulin 2 mg/kg/daily IV days -2, -1 and 0 (n=80). Recipients of haplo- related and mismatched unrelated donor transplantation received cyclophosphamide 50 mg/kg IV on day +3 and +4 along with Mesna (n=36). All patients received post-transplant immunosuppression with Tacrolimus and Mycophenolate Mofetil. Patients with urinary symptoms were tested for BKV in urine by PCR. Results The median age of patients was 56 years (range 20–76). A total of 31% of patients (n=13) received PTCY in FBT group which was similar to 31% of patients (n=23) in FB4-FB2 (p=0.98). Overall 21.5% patients were diagnosed with BKHC. The patients who received ATG, the incidence of BKHC was 27.5% in FBT group and 11.7 % in FB4-FB2 (p=0.073). The patients who received PTCY, the incidence of BKHC was significantly increased to 69.2% in FBT vs 9% in FB4-FB2 (p=0.0001). The risk of developing concurrent CMV viremia and BKHC was increased to 10.3% in FBT compared to 5.8% in FB2-FB4 (p=0.662). The patients who received PTCY following FBT, the incidence of concurrent CMV viremia and BKHC was increased to 23.1%. as compared to 0% with FB2-FB4. Conclusion Our result shows the addition of PTCY to TBI containing regimen significantly increased the incidence of BKHC. We did not observe increase in the incidence of BKHC in patients receiving PTCY with FB2 or FB4 regimens. Our study revealed an increased incidence of concurrent BKHC and CMV viremia in patients receiving PTCY with FBT which could be due to increased immunosuppression. Our findings suggest that using PTCY as GVHD prophylaxis in patients undergoing MA conditioning regimen including TBI is a risk factor for BKHC.

Research Highlights

Research Highlights

Risk Factors of BK Virus Cystitis in Haematopoietic Stem Cell Transplantation-a Retrospective Monocentric Study

Background: BK virus (BKV) is a human polyomavirus. Reactivation occurs during deep immunosuppression as in hematopoietic stem cell transplantation (HSCT) and renal transplantation, leading to hemorrhagic cystitis (HC) and nephropathy respectively. In HSCT, systematic PCR for BKV in urine is positive for 50 to 100% of patients (pts), but only 5 to 40% develop a BKV HC. Thus, BKV PCR is usefull to confirm a diagnostic of BKV HC but not to predict its occurrence. Several risk factors to develop BKV HC have been studied, especially mismatched HLA and haploidentical HSCT.Objectives: The aim of this retrospective study was to ascertain the risk factors to develop BKV HC.Methods: A retrospective study was performed by considering data from Grenoble University Hospital in the national retrospective register ProMISe, from the SFGM-TC. The period of the study covered from January 2014 to January 2018. PCR BKV in urine was performed when pts presented hematuria grade 2 or higher with clinical symptoms of cystitis. Viral nucleic acid was extracted from the urine samples with the EasyMag platform (Biomérieux) and the qPCR with BK Virus R-GENE®kit (ARGENE) on a LightCycler 480 (ROCHE). BKV HC is defined by the association of clinical symptoms of cystitis, haematuria grade 2 or higher and a BKV viruria >7 log10 copies/mL. Univariable and multivariable logistic regression model were used to identify risk factors for BK cystitis.Results: 188 HSCT were performed during the study period. After exclusion of 13 pts for early mortality (<30 days) and 4 for engraftment failure, 171 pts were finally considered for analysis, from whom 43 (25.1%) developed a BKV HC. The median age of patients presenting with BKV HC was 44 years (23-62) and males represented 67.4 %. Acute leukemia was the most common indication of HSCT (74.4%), followed by myelodysplastic syndromes (9.3%), lymphoma (6.9%), myeloproliferative neoplasms (4.7%) and aplastic anemia (4.7%). In most cases, pts were not in complete response at transplant (51.2%). First autologous or allogenic HSCT had previously been performed for 30.2% of pts. The majority of pts had a transplant with peripheral stem cells as graft source (76.6%), and had a transplant with mismatched HLA (9/10, n=9, 20.9%) or haploidentical donors (n=13, 30.2%). Twenty-nine pts (67.4%) received reduced-intensity conditioning and twenty-two pts (51.2%) received cyclophosphamide post allograft to prevent Graft Versus Host Disease (GVHD). BKV HC prophylaxis relied on hyperhydratation and mesna during the conditioning regimen.The median time to develop HC was 42 days post-transplantation (30-55) mainly with a grade 3 HC (53.5%). The median viruria was 9 log (9-10). Cidofovir was administered as curative treatment to 20 pts (46.5%) and 25 pts (58%) needed bladder irrigation and forced diuresis. The median level of platelets at diagnosis was 58 G/L (29-123). At diagnosis of BKV HC, 32.6% of pts presented a bacterial cystitis and 62.8% an acute renal failure. Allogenic HSCT was complicated by an acute GVHD in 88.4% of pts and 69.8% were treated by corticosteroids. CMV reactivation was observed in 39.5% of pts, and HHV6 in 18.6%.In univariate analysis, post-transplant cyclophosphamide (p<0.001), age below 40 years (p<0.001), history of previous auto or allograft (p=0.007), allograft with mismatched HLA (9/10 and haploidentical) (p<0.001), use of peripheral stem cells (p=0.047), engraftment of platelets >100 days (p=0.016), acute GVHD (p=0.007), corticotherapy (p<0.001), co-infection by HHV6 (p=0.006), association to bacterial cystitis (p=0.002), acute renal failure (p=0.009) and platelets below 50G/L (p<0.001) were significantly associated with increased risk of BKV HC.After logistic regression, the risk factors associated with BKV HC were reduced to: exposition post-transplantation to cyclophosphamide (OR 4.1, 1.5-10.7, p=0.004), age below 40 years (OR 4.1, 1.6-10.9, p=0.004), corticosteroids therapy (OR 3.9, 1.6-9.5, p=0.033), acute renal failure (OR 3.8, 1.5-9.6, p=0.0056), bacterial cystitis (OR 3.3, 1.2-8.7, p=0.0175), and platelets below 50G/L (OR 3.8, 1.382-10.486, p=0.097).Conclusion: BKV HC was observed in 25.1% of patients. Exposition to cyclophosphamide, young age, corticosteroids therapy and bacterial cystitis are potential risk factors of BKV HC. Surprisingly, young age was not expected as risk factor. DisclosuresNo relevant conflicts of interest to declare.

Late Immune Reconstitution and Its Relationship with Infections in Patients with Fanconi Anemia and Bone Marrow Transplantation

BackgroundFanconi anemia (FA) is a condition characterized by congenital malformations, low height, and progressive bone marrow failure during childhood, genomic instability and hypersensitivity to DNA cross-linking agents. Bone marrow transplantation (BMT), is currently the only treatment capable to restore normal hematopoiesis and improve survival of these patients. To achieve a successful allogeneic BMT, a normal T-cell immunity reconstitution is required.1,2ObjectiveTo describe the kinetics of immune reconstitution in six patients with FA after BMT, having used a reduce intensity conditioning regimen, well as associated infections during the post-transplant process.MethodsWe describe the distribution in peripheral blood of CD3+ T lymphocytes, CD16 +/CD56+ NK cells, CD4+ helper T lymphocytes, CD8+ cytotoxic T lymphocytes and CD19+/CD20+ B cells, in six patients with FA, after BMT from an HLA-matching sibling and complete chimerism, on days +90, +120, +150, +180, +210 and +360. The conditioning regimen employed consisted of fludarabine (Flu) 150 mg/m2, cyclophosphamide 20 mg/kg and rabbit anti-thymocyte globulin (r-ATG) 20 mg/kg. Infection was determined by a positive reaction of the DNA polymerase chain to Cytomegalovirus (CMV), Epstein-Barr virus, Adenovirus and BK virus (BKV), as well as galactomannan antigen and antibodies against Candida sp, or positive bacterial cultures.ResultsWe observed different kinetics regarding the recovery of different lymphocyte subpopulations, starting from day +90. CD16+/CD56+ NK cells recovered first, between days 90 and 120, followed by CD8+ T lymphocytes between day +120 and +150, CD19+/CD20+ B cells between day +180 and +210, and finally, CD4+ T lymphocytes starting from day 210. Five patients presented infection in the post-BMT stage. Four patients before +90, developed CMV infection, based on positive reaction of the CMV polymerase chain. All patient responses to ganciclovir therapy and no CMV disease were documented. The fifth patient presented with meningitis due to Lysteria monocitogenes and BKV hemorrhagic cystitis at day +153; this patient had the diagnosis of chronic-graft versus host disase, and was treated with ampicillin, rifampicin and intravenous immunoglobulin, evolving satisfactorily. All patients remain alive and well.DiscussionMost patients in our report developed CMV infection, as being reported with FLU and anti-thymocyte globulin combination. We observed a later reconstitution in comparison with patients in whom lower doses of r-ATG (<10 mg/kg) have been used3. In our group of patients, reconstitution of NK cells and CD8+ T lymphocytes, helped to reduce the frequency of asymptomatic viral infections, as reconstitution of innate immunity and cytotoxic CD8+ T lymphocytes can achieve effective antiviral effector responses, allowing for the control of viral infections, until reconstitution of CD4+ T lymphocytes were fully achieved. The infectious complications associated with this prolonged state of profound immunosuppression and late immune reconstitution, can be attenuated with a closely follow-up for these infectious agents through PCR-mediated detection techniques, which allows an early diagnosis and prompt treatment.ConclusionImmunological reconstitution after a BMT in FA patients is determinant for morbidity and mortality, mainly due to opportunistic infections and GVHD. We observed that recovery kinetics of different lymphocyte populations is different in cases in which higher doses of r-GAT are used, also an early detection and prompt treatment of opportunistic infections may be determinant for patient's survival.Conflict-of-interest disclosure: The authors declare they have nothing to disclose.BibliographyOgonek J, Kralj Juric M, Ghimire S, Varanasi PR, Holler E, Greinix H, et al. Immune reconstitution after allogenic hematopoietic stem cell transplantation. Front immunol. 2016; 7 (507):1-15.Smith AR, Wagner JE. Current clinical management of Fanconi anemia. Expert Rev Hematol. 2012; 5 (5): 513-522.Perlingeiro-Beltrame M, Malvezzi M, Bonfim C, Tadeu Covas D, Pasquini R. Immune reconstitution in patients with Fanconi anemia after allogeneic bone marrow transplantation. Cytotherapy. 2014; 0: 1e14. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Safety and Feasibility of Administration of High Doses of Ex Vivo Expanded NK Cells for Prevention of Disease Relapse after Transplantation for Patients with Myeloid Malignancies - Final Results of a Phase I Clinical Trial

Background: Disease relapse remains the most common cause of treatment failure after transplantation. To enhance anti-tumor effect of the graft we explored the use of high doses of donor-derived ex vivo expanded NK cells administered after haploidentical stem cell transplantation (HaploSCT) with the ultimate goal to decrease relapsed rate post-transplant.Methods: We aimed to study safety and determine the maximum tolerated dose (MTD) of high doses of mbIL-21 ex vivo expanded NK cells in a phase I clinical trial (clinicaltrials.gov NCT01904136) administered post-transplant in patients with myeloid malignancies (AML, CML, MDS). We hypothesized that infusion of mature NK cells would compensate for the lower NK-cell numbers and poor function previously observed by our group in the first month post-transplant. Patients received conditioning with melphalan 140mg/m2, fludarabine 160mg/m2 and 2GyTBI, and GVHD prophylaxis with post-transplant cyclophosphamide, tacrolimus and mycophenolate (Gaballa S, et al. Cancer. 2016). All patients had a bone marrow graft. NK cells were generated from peripheral blood mononuclear cells of the same donor with infusions on Days -2, +7 and on/after +28. The first infusion was with fresh and the other two were with cryopreserved NK cells. Dose escalation was planned in cohorts of 2 patients starting at 1x105 to 1x109 NK cells/Kg. Having an NK-cell alloreactive donor or certain KIR genotype was not a requirement to participate in this study, although these characteristics were evaluated in all patients.Results: Thirteen patients were enrolled. Eight patients had AML (7 in CR1, 4 with high-risk cytogenetics, 3 had primary induction failure AML and 3 had +minimal residual disease (MRD) at transplant, and one FLT3+ AML in CR2 with persistent MRD by flow cytometry), and 5 had CML (4 in second chronic phase, 2 with prior CNS disease, one had associated MDS with monosomy 7, and 2 who failed multiple TKIs). The median age was 41.5 years (range 18-60). Five patients were males and 8 females. The NK-cell dose escalation was as follows: 1x105/kg (N=2), 1x106/kg (N=3), 1x107/kg (N=3), 3x107/kg (N=2) and 1x108/kg (N=2). One patient was treated with 1x104/kg (Dose -1). All patients received the 3 planned infusions except one. Median purity of the NK-cell product was 98.98%. All patients achieved primary engraftment (100%) with 100% donor chimerism except one patient (who received 1x104/kg) who had secondary graft failure with concurrent parainfluenza pneumonia and died of treatment-related mortality (TRM). The median time to neutrophil and platelet engraftment was 18 and 26 days, respectively. Of 12 patients evaluable for aGVHD, the maximum grade was II in 7 patients. No grade III-IV aGVHD or cGVHD was observed. Only 5/12 patients had CMV reactivation (41.6% compared with 71% in retrospective data with the same treatment without NK cells), while none developed BK virus hemorrhagic cystitis. All patients (N=12) achieved remission with negative MRD after transplant. One patient treated NK cells at 1x105/kg/dose relapsed, received salvage treatment and was alive at last follow-up. All other patients are alive and in complete remission (N=11) after a median follow-up of 12.8 months (range 6-25.1). Compared with patients treated on a previous clinical trial with the same conditioning without NK cells (AML in CR1/2 and CML in CP), the patients who received NK cells had marked improvement in NK-cell function and cytotoxicity, as well as a significantly increase in INF gamma and TNF alpha production. A lower relapse rate and improved survival was observed compared with the retrospective cohort of patients treated without NK cells, although not statistically significant (p=0.21) (Figure 1).Conclusions: Doses up to 3x108/kg total dose of mbIL-21 ex vivo expanded NK cells obtained from the same donor can be safely administered in the early post-transplant period after HaploSCT. This was the maximum feasible dose to be manufactured in the current system, while no toxicity or increase in GVHD was observed. Three infusions of 1x108 NK cells per kg will be administered in the phase II study [Display omitted] DisclosuresCiurea:Spectrum Pharmaceuticals: Other: Advisory Board; Cyto-Sen Therapeutics: Equity Ownership. Lee:Sanofi: Consultancy; Cyto-Sen Therapeutics: Equity Ownership, Other: Board of Directors; Intellia Therapeutics: Other: Advisory Board; Courier Therapeutics: Other: Advisory Board; Intrexon: Consultancy, Patents & Royalties; Shire: Other: Advisory Board; Ziopharm: Consultancy, Patents & Royalties. Bashir:Spectrum: Consultancy; Celgene: Research Funding; Takeda: Research Funding; Takeda: Consultancy. Champlin:Intrexon: Equity Ownership, Patents & Royalties; Ziopharm Oncology: Equity Ownership, Patents & Royalties.