Intraventricular CARv3-TEAM-E T Cells in Recurrent Glioblastoma.

In this first-in-human, investigator-initiated, open-label study, three participants with recurrent glioblastoma were treated with CARv3-TEAM-E T cells, which are chimeric antigen receptor (CAR) T cells engineered to target the epidermal growth factor receptor (EGFR) variant III tumor-specific antigen, as well as the wild-type EGFR protein, through secretion of a T-cell-engaging antibody molecule (TEAM). Treatment with CARv3-TEAM-E T cells did not result in adverse events greater than grade 3 or dose-limiting toxic effects. Radiographic tumor regression was dramatic and rapid, occurring within days after receipt of a single intraventricular infusion, but the responses were transient in two of the three participants. (Funded by Gateway for Cancer Research and others; INCIPIENT ClinicalTrials.gov number, NCT05660369.).

Phase 1 study of CAR-37 T cells in patients with relapsed or refractory CD37+ lymphoid malignancies.

We report on the first-in-human clinical trial using chimeric antigen receptor (CAR) T-cells targeting CD37, an antigen highly expressed in B- and T-cell malignancies (clinicaltrials.gov NCT04136275). Five patients with relapsed or refractory CD37+ lymphoid malignancies were enrolled and infused with autologous CAR-37 T-cells. CAR-37 T-cells expanded in the peripheral blood of all patients and, at peak, comprised >94% of the total lymphocytes in 4/5 patients. Tumor responses were observed in 4/5 patients, with 3 complete responses, 1 mixed response, and 1 patient whose disease progressed rapidly and with relative loss of CD37 expression. Three patients experienced prolonged and severe pancytopenia, and in two of these patients, efforts to ablate CAR-37 T-cells (which were engineered to co-express truncated EGFR) with cetuximab, were unsuccessful. Hematopoiesis was restored in these two patients following allogeneic hematopoietic stem cell transplantation. No other severe, non-hematopoietic toxicities occurred. We investigated the mechanisms of profound pancytopenia and did not observe activation of CAR-37 T-cells in response to hematopoietic stem cells in vitro or hematotoxicity in humanized models. Patients with pancytopenia had sustained high levels of IL-18, with low levels of IL-18 binding protein in their peripheral blood. IL-18 levels were significantly higher in CAR-37-treated patients relative to both cytopenic and non-cytopenic cohorts of CAR-19-treated cohorts of patients. In conclusion, CAR-37 T-cells exhibited anti-tumor activity, with significant CAR expansion and cytokine production. CAR-37 T-cells may be an effective therapy in hematologic malignancies as a bridge to hematopoietic stem cell transplant.

Phase 2 clinical trial evaluating abatacept in patients with steroid-refractory chronic graft-versus-host disease.

Steroid-refractory chronic graft-versus-host disease (cGVHD) after allogeneic transplant remains a significant cause of morbidity and mortality. Abatacept is a selective costimulation modulator, used for the treatment of rheumatologic diseases, and was recently the first drug to be approved by the US Food and Drug Administration for the prophylaxis of acute graft-versus-host disease. We conducted a phase 2 study to evaluate the efficacy of abatacept in steroid-refractory cGVHD. The overall response rate was 58%, seen in 21 out of 36 patients, with all responders achieving a partial response. Abatacept was well tolerated with few serious infectious complications. Immune correlative studies showed a decrease in interleukin -1α (IL-1α), IL-21, and tumor necrosis factor α as well as decreased programmed cell death protein 1 expression by CD4+ T cells in all patients after treatment with abatacept, demonstrating the effect of this drug on the immune microenvironment. The results demonstrate that abatacept is a promising therapeutic strategy for the treatment of cGVHD. This trial was registered at www.clinicaltrials.gov as #NCT01954979.

Allogeneic B cell immunomodulatory therapy in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is an orphan neurodegenerative disease. Immune system dysregulation plays an essential role in ALS onset and progression. Our preclinical studies have shown that the administration of exogenous allogeneic B cells improves outcomes in murine models of skin and brain injury through a process termed pligodraxis, in which B cells adopt an immunoregulatory and neuroprotective phenotype in an injured environment. Here, we investigated the effects of B-cell therapy in the SOD1G93A mouse preclinical model of ALS and in a person living with ALS. Purified splenic mature naïve B cells from haploidentical donor mice were administered intravenously in SOD1G93A mice for a total of 10 weekly doses. For the clinical study in a person with advanced ALS, IgA gammopathy of unclear significance, and B lymphopenia, CD19+ B cells were positively selected from a healthy haploidentical donor and infused intravenously twice, at a 60-day interval. Repeated intravenous B-cell administration was safe and significantly delayed disease onset, extended survival, reduced cellular apoptosis, and decreased astrogliosis in SOD1G93A mice. Repeated B-cell infusion in a person with ALS was safe and did not appear to generate a clinically evident inflammatory response. An improvement of 5 points on the ALSFRS-R scale was observed after the first infusion. Levels of inflammatory markers showed persistent reduction post-infusion. This represents a first demonstration of the efficacy of haploidentical B-cell infusion in the SOD1G93A mouse and the safety and feasibility of using purified haploidentical B lymphocytes as a cell-based therapeutic strategy for a person with ALS.

Tabelecleucel for allogeneic haematopoietic stem-cell or solid organ transplant recipients with Epstein-Barr virus-positive post-transplant lymphoproliferative disease after failure of rituximab or rituximab and chemotherapy (ALLELE): a phase 3, multicentre, open-label trial.

BACKGROUND: Survival in Epstein-Barr virus (EBV)-positive post-transplant lymphoproliferative disease following haematopoietic stem-cell transplant (HSCT) or solid organ transplant (SOT) is poor after failure of initial therapy, indicating an urgent need for therapies for this ultra-rare disease. With recent EU marketing authorisation, tabelecleucel is the first off-the-shelf, allogeneic, EBV-specific T-cell immunotherapy to receive approval for treatment of relapsed or refractory EBV-positive post-transplant lymphoproliferative disease. We aimed to determine the clinical benefit of tabelecleucel in patients with relapsed or refractory EBV-positive post-transplant lymphoproliferative disease following HSCT or SOT. METHODS: In this global, multicentre, open-label, phase 3 trial, eligible patients (of any age) had biopsy-proven EBV-positive post-transplant lymphoproliferative disease, disease that was relapsed or refractory to rituximab after HSCT and rituximab with or without chemotherapy after SOT, and partially HLA-matched and appropriately HLA-restricted tabelecleucel available. Patients received tabelecleucel administered intravenously at 2 × 106 cells per kg on days 1, 8, and 15 in 35-day cycles and are assessed for up to 5 years for survival post-treatment initiation. The primary endpoint was objective response rate. All patients who received at least one dose of tabelecleucel were included in safety and efficacy analyses. This trial is registered with ClinicalTrials.gov, NCT03394365, and is ongoing. FINDINGS: From June 27, 2018, to Nov 5, 2021, 63 patients were enrolled, of whom 43 (24 [56%] male and 19 [44%] female) were included, 14 had prior HSCT, 29 had SOT. Seven (50%, 95% CI 23-77) of 14 participants in the HSCT group and 15 (52%, 33-71) of 29 participants in the SOT group had an objective response, with a median follow-up of 14·1 months (IQR 5·7-23·9) and 6·0 months (1·8-18·4), respectively. The most common grade 3 or 4 treatment-emergent adverse events were disease progression (in four [29%] of 14 in HSCT and eight [28%] of 29 in SOT) and decreased neutrophil count (in four [29%] of 14 in HSCT and four [14%] of 29 in SOT). Treatment-emergent serious adverse events were reported in 23 (53%) of 43 patients and fatal treatment-emergent adverse events in five (12%); no fatal treatment-emergent adverse event was treatment-related. There were no reports of tumour flare reaction, cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, transmission of infectious diseases, marrow rejection, or infusion reactions. No events of graft-versus-host disease or SOT rejection were reported as related to tabelecleucel. INTERPRETATION: Tabelecleucel provides clinical benefit in patients with relapsed or refractory EBV-positive post-transplant lymphoproliferative disease, for whom there are no other approved therapies, without evidence of safety concerns seen with other adoptive T-cell therapies. These data represent a potentially transformative and accessible treatment advance for patients with relapsed or refractory disease with few treatment options. FUNDING: Atara Biotherapeutics.

Post-Transcriptional Genetic Silencing of BCL11A to Treat Sickle Cell Disease.

BACKGROUND: Sickle cell disease is characterized by hemolytic anemia, pain, and progressive organ damage. A high level of erythrocyte fetal hemoglobin (HbF) comprising α- and γ-globins may ameliorate these manifestations by mitigating sickle hemoglobin polymerization and erythrocyte sickling. BCL11A is a repressor of γ-globin expression and HbF production in adult erythrocytes. Its down-regulation is a promising therapeutic strategy for induction of HbF. METHODS: We enrolled patients with sickle cell disease in a single-center, open-label pilot study. The investigational therapy involved infusion of autologous CD34+ cells transduced with the BCH-BB694 lentiviral vector, which encodes a short hairpin RNA (shRNA) targeting BCL11A mRNA embedded in a microRNA (shmiR), allowing erythroid lineage-specific knockdown. Patients were assessed for primary end points of engraftment and safety and for hematologic and clinical responses to treatment. RESULTS: As of October 2020, six patients had been followed for at least 6 months after receiving BCH-BB694 gene therapy; median follow-up was 18 months (range, 7 to 29). All patients had engraftment, and adverse events were consistent with effects of the preparative chemotherapy. All the patients who could be fully evaluated achieved robust and stable HbF induction (percentage HbF/(F+S) at most recent follow-up, 20.4 to 41.3%), with HbF broadly distributed in red cells (F-cells 58.9 to 93.6% of untransfused red cells) and HbF per F-cell of 9.0 to 18.6 pg per cell. Clinical manifestations of sickle cell disease were reduced or absent during the follow-up period. CONCLUSIONS: This study validates BCL11A inhibition as an effective target for HbF induction and provides preliminary evidence that shmiR-based gene knockdown offers a favorable risk-benefit profile in sickle cell disease. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT03282656).

An improved index for diagnosis and mortality prediction in malignancy-associated hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening inflammatory syndrome that may complicate hematologic malignancies (HMs). The appropriateness of current criteria for diagnosing HLH in the context of HMs is unknown because they were developed for children with familial HLH (HLH-2004) or derived from adult patient cohorts in which HMs were underrepresented (HScore). Moreover, many features of these criteria may directly reflect the underlying HM rather than an abnormal inflammatory state. To improve and potentially simplify HLH diagnosis in patients with HMs, we studied an international cohort of 225 adult patients with various HMs both with and without HLH and for whom HLH-2004 criteria were available. Classification and regression tree and receiver-operating curve analyses were used to identify the most useful diagnostic and prognostic parameters and to optimize laboratory cutoff values. Combined elevation of soluble CD25 (>3900 U/mL) and ferritin (>1000 ng/mL) best identified HLH-2004-defining features (sensitivity, 84%; specificity, 81%). Moreover, this combination, which we term the optimized HLH inflammatory (OHI) index, was highly predictive of mortality (hazard ratio, 4.3; 95% confidence interval, 3.0-6.2) across diverse HMs. Furthermore, the OHI index identified a large group of patients with high mortality risk who were not defined as having HLH according to HLH-2004/HScore. Finally, the OHI index shows diagnostic and prognostic value when used for routine surveillance of patients with newly diagnosed HMs as well as those with clinically suspected HLH. Thus, we conclude that the OHI index identifies patients with HM and an inflammatory state associated with a high mortality risk and warrants further prospective validation.

Efficacy of Tocilizumab in Patients Hospitalized with Covid-19.

BACKGROUND: The efficacy of interleukin-6 receptor blockade in hospitalized patients with coronavirus disease 2019 (Covid-19) who are not receiving mechanical ventilation is unclear. METHODS: We performed a randomized, double-blind, placebo-controlled trial involving patients with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, hyperinflammatory states, and at least two of the following signs: fever (body temperature >38°C), pulmonary infiltrates, or the need for supplemental oxygen in order to maintain an oxygen saturation greater than 92%. Patients were randomly assigned in a 2:1 ratio to receive standard care plus a single dose of either tocilizumab (8 mg per kilogram of body weight) or placebo. The primary outcome was intubation or death, assessed in a time-to-event analysis. The secondary efficacy outcomes were clinical worsening and discontinuation of supplemental oxygen among patients who had been receiving it at baseline, both assessed in time-to-event analyses. RESULTS: We enrolled 243 patients; 141 (58%) were men, and 102 (42%) were women. The median age was 59.8 years (range, 21.7 to 85.4), and 45% of the patients were Hispanic or Latino. The hazard ratio for intubation or death in the tocilizumab group as compared with the placebo group was 0.83 (95% confidence interval [CI], 0.38 to 1.81; P = 0.64), and the hazard ratio for disease worsening was 1.11 (95% CI, 0.59 to 2.10; P = 0.73). At 14 days, 18.0% of the patients in the tocilizumab group and 14.9% of the patients in the placebo group had had worsening of disease. The median time to discontinuation of supplemental oxygen was 5.0 days (95% CI, 3.8 to 7.6) in the tocilizumab group and 4.9 days (95% CI, 3.8 to 7.8) in the placebo group (P = 0.69). At 14 days, 24.6% of the patients in the tocilizumab group and 21.2% of the patients in the placebo group were still receiving supplemental oxygen. Patients who received tocilizumab had fewer serious infections than patients who received placebo. CONCLUSIONS: Tocilizumab was not effective for preventing intubation or death in moderately ill hospitalized patients with Covid-19. Some benefit or harm cannot be ruled out, however, because the confidence intervals for efficacy comparisons were wide. (Funded by Genentech; ClinicalTrials.gov number, NCT04356937.).

Molecular and cellular features of CTLA-4 blockade for relapsed myeloid malignancies after transplantation.

Relapsed myeloid disease after allogeneic stem cell transplantation (HSCT) remains largely incurable. We previously demonstrated the potent activity of immune checkpoint blockade in this clinical setting with ipilimumab or nivolumab. To define the molecular and cellular pathways by which CTLA-4 blockade with ipilimumab can reinvigorate an effective graft-versus-leukemia (GVL) response, we integrated transcriptomic analysis of leukemic biopsies with immunophenotypic profiling of matched peripheral blood samples collected from patients treated with ipilimumab following HSCT on the Experimental Therapeutics Clinical Trials Network 9204 trial. Response to ipilimumab was associated with transcriptomic evidence of increased local CD8+ T-cell infiltration and activation. Systemically, ipilimumab decreased naïve and increased memory T-cell populations and increased expression of markers of T-cell activation and costimulation such as PD-1, HLA-DR, and ICOS, irrespective of response. However, responding patients were characterized by higher turnover of T-cell receptor sequences in peripheral blood and showed increased expression of proinflammatory chemokines in plasma that was further amplified by ipilimumab. Altogether, these data highlight the compositional T-cell shifts and inflammatory pathways induced by ipilimumab both locally and systemically that associate with successful GVL outcomes. This trial was registered at www.clinicaltrials.gov as #NCT01822509.

Contribution of clonal hematopoiesis to adult-onset hemophagocytic lymphohistiocytosis.

Adult-onset hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disease of immune hyperactivation. Unlike pediatric HLH, adult HLH is rarely driven by germline genetic variants. Although numerous precipitating etiologies have been identified, the reason that HLH occurs in only a subset of individuals and how other factors contribute to the disease remains unknown. We hypothesized that clonal hematopoiesis (CH), a state in which somatic mutations in blood cells cause an expanded population of mutant hematopoietic cells and drive an aberrant inflammatory state, could contribute to adult-onset HLH. In a highly annotated cohort of older adults with HLH we found that CH was more prevalent than in control cohorts. Using the adult-onset HLH mouse model in which repeated treatments of the TLR9 agonist, ODN1826, was delivered to the mouse, we observed that macrophages carrying mutations in Tet2, one of the most commonly mutated genes in CH, have an enhanced inflammatory response to TLR9 agonism. Finally, mice carrying Tet2 mutations in the hematopoietic compartment (a common model for CH) displayed an exaggerated response to TLR9 agonism, including worse splenomegaly and anemia. Our data suggest that CH is more common in individuals with adult-onset HLH and can contribute to the pathophysiology of this disease.

A multicenter phase 1 study of nivolumab for relapsed hematologic malignancies after allogeneic transplantation.

Programmed cell death-1 (PD-1)/programmed death ligand-1 blockade may potentially augment graft-vs-tumor effects following allogeneic hematopoietic cell transplantation (alloHCT), but retrospective studies of anti-PD-1 therapy reported substantial toxicity from graft-versus-host-disease (GVHD). Here, we report the results of a prospective clinical trial of PD-1 blockade for relapsed hematologic malignancies (HMs) after alloHCT (NCT01822509). The primary objective in this phase 1 multicenter, investigator-initiated study was to determine maximum tolerated dose and safety. Secondary objectives were to assess efficacy and immunologic activity. Patients with relapsed HMs following alloHCT were eligible. Nivolumab was administered every 2 weeks until progression or unacceptable toxicity, starting with a 1-mg/kg cohort, with planned deescalation based on toxicity to a 0.5-mg/kg cohort. Twenty-eight patients were treated (n = 19 myeloid, n = 9 lymphoid). Median age was 57 years (range 27-76), and median time from alloHCT to enrollment was 21 months (range 5.6-108.5). Two of 6 patients treated at 1 mg/kg experienced dose-limiting toxicity (DLT) from immune-related adverse events (irAEs). Twenty-two patients were treated at 0.5 mg/kg, and 4 DLTs occurred, including 2 irAEs and 2 with fatal GVHD. The overall response rate in efficacy-evaluable patients was 32% (8/25). With a median follow-up of 11 months, the 1-year progression-free survival and overall survival were 23% and 56%, respectively. In this first prospective clinical trial of an anti-PD-1 antibody for post-alloHCT relapse, GVHD and irAEs occurred, requiring dose deescalation, with only modest antitumor activity. Further studies of anti-PD-1 therapy post-alloHCT may require specific toxicity mitigation strategies. This trial was registered at www.clinicaltrials.gov as #NCT01822509.

Phenotypic and functional characterization of the CD6-ALCAM T-cell co-stimulatory pathway after allogeneic cell transplantation.

CD6 is a co-stimulatory receptor expressed on T cells that binds activated leukocyte cell adhesion molecule (ALCAM), expressed on antigen presenting cells, epithelial and endothelial tissues. The CD6-ALCAM pathway plays an integral role in modulating T-cell activation, proliferation, and trafficking. In this study we examined expression of CD6 by reconstituting T cells in 95 patients after allogeneic cell transplantation and evaluated the effects of itolizumab, an anti- CD6 monoclonal antibody, on T-cell activation. CD6 T cells reconstituted early after transplant with CD4 regulatory T cells (Treg)-expressing lower levels of CD6 compared to conventional CD4 T cells (Tcon) and CD8 T cells. After onset of acute graft-versus-host disease (aGvHD), CD6 expression was further reduced in Treg and CD8 T cells compared to healthy donors, while no difference was observed for Tcon. ALCAM expression was highest in plasmacytoid dendritic cells (pDC), lowest in myeloid dendritic cells (mDC) and intermediate in monocytes and was generally increased after aGvHD onset. Itolizumab inhibited CD4 and CD8 T-cell activation and proliferation in preGvHD samples, but inhibition was less prominent in samples collected after aGvHD onset, especially for CD8 T cells. Functional studies showed that itolizumab did not mediate direct cytolytic activity or antibody-dependent cytotoxicity in vitro. However, itolizumab efficiently abrogated the costimulatory activity of ALCAM on T-cell proliferation, activation and maturation. Our results identify the CD6-ALCAM pathway as a potential target for aGvHD control and a phase I/II study using itolizumab as first line treatment in combination with steroids for patients with aGvHD is currently ongoing (clinicaltrials gov. Identifier: NCT03763318).

Comparative analysis of cell therapy infusion workflows at clinical sites.

BACKGROUND AIMS: Cell therapies are an emerging treatment option for a variety of diseases, especially with the success of chimeric antigen receptor T-cell therapies. With 18 FDA-approved cell therapy products as of December 2020 and a growing number in clinical trials, standards for most aspects of the cell therapy lifecycle are well-established by professional organizations like AABB and FACT; however, there are limited standardized protocols regarding the day-of infusion. METHODS: Infusions were observed at three academic medical centers in the United States, and the workflows were analyzed and compared based on factors including facility layout, product verification processes, cryobag design, timing restrictions, and use of electronic medical records. RESULTS: Variations between the facilities were identified with product thawing location and cell therapy lab location being the most important factors in time from thaw to infusion. CONCLUSIONS: Based on this analysis, opportunities were identified for standardization and streamlining the infusion workflow which may help facilitate adoption of new and existing cell therapies at a wider range of hospitals.

T Cell Clonal Dynamics Determined by High-Resolution TCR-ß Sequencing in Recipients after Allogeneic Hematopoietic Cell Transplantation.

Delayed reconstitution of the immune system is a long-recognized complication after allogeneic hematopoietic cell transplantation (HCT). Specifically, loss of T cell diversity has been thought to contribute to infectious complications, graft-versus-host disease (GVHD), and disease relapse. We performed serial high-resolution next-generation sequencing of T cell receptor (TCR)-ß in 99 related or unrelated donor (57 unrelated, 42 related) allogeneic HCT recipients (55 with reduced-intensity conditioning, 44 with myeloablative conditioning) during the first 3 months after HCT using the immunoSEQ Assay. We measured T cell fraction, clonality (1- Peilou's evenness) and Daley-Smith richness from recipient samples at multiple time points. In agreement with previous studies, we found that although absolute T cell numbers recover relatively quickly after HCT, T cell repertoire diversity remains diminished. Restricted diversity was associated with conditioning intensity, use of antithymocyte globulin, and donor type. Increased number of expanded clones compared to donor T cell clones at day +30 was associated with the incidence of acute GVHD (hazard ratio [HR], 1.11; P = .00005). Even after exclusion of the 12 patients who developed acute GVHD before day +30, the association between acute GVHD and increased clonal expansion at day +30 remained (HR, 1.098; P = .041), indicating that increased clonal T cell expansion preceded the development of acute GVHD. Our results highlight T cell clonal expansion as a potential novel biomarker for acute GVHD that warrants further study.

Analysis of the Whole CDR3 T Cell Receptor Repertoire after Hematopoietic Stem Cell Transplantation in 2 Clinical Cohorts.

A major cause of morbidity and mortality for patients who undergo hematologic stem cell transplantation (HSCT) is acute graft-versus-host disease (aGVHD), a mostly T cell-mediated disease. Examination of the T cell receptor (TCR) repertoire of HSCT recipients and the use of next-generation nucleotide sequencing have raised the question of whether features of TCR repertoire reconstitution might reproducibly associate with aGVHD. We hypothesized that the peripheral blood TCR repertoire of patients with steroid-nonresponsive aGVHD would be less diverse. We also hypothesized that patients with GVHD who shared HLA might also share common clones at the time of GVHD diagnosis, thereby potentially providing potential clinical indicators for treatment stratification. We further hypothesized that HSCT recipients with the same HLA mismatch might share a more similar TCR repertoire based on a potentially shared focus of alloreactive responses. We studied 2 separate patient cohorts and 2 separate platforms for measuring TCR repertoire. The first cohort of patients was from a multicenter Phase III randomized double-blinded clinical trial of patients who developed aGVHD (NCT01002742). The second cohort comprised samples from biobanks from 2 transplantation centers and the Center for International Blood and Marrow Transplant Research of patients who underwent mismatched HSCT. There were no statistically significant differences in the TCR diversity of steroid responders and nonresponders among patients with aGVHD on the day of diagnosis. Most clones in the repertoire were unique to each patient, but a small number of clones were found to be both exclusive to and shared among aGVHD nonresponders. We were also able to show a strong correlation between the presence of Vß20 and Vß29 and steroid responsiveness. Using the Bhattacharya coefficient, those patients who shared the same HLA mismatch were shown to be no more similar to one another than to those who had a completely different mismatch. Using 2 separate clinical cohorts and 2 separate platforms for analyzing the TCR repertoire, we have shown that the sampled human TCR repertoire is largely unique to each patient but contains glimmers of common clones of subsets of clones based on responsiveness to steroids in aGVHD on the day of diagnosis. These studies are informative for future strategies to assess for reproducible TCR responses in human alloreactivity and possible markers of GVHD responsiveness to therapy.

Incidence, Predictors, and Outcomes of Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome after Reduced-Intensity Allogeneic Hematopoietic Cell Transplantation.

fludarabine with intravenous busulfan at doses of 3.2 mg/kg (Flu/Bu1) or 6.4 mg/kg (Flu/Bu2). Hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a serious complication of hematopoietic stem cell transplantation (HCT) that is felt to be triggered, at least in part, by damage to the liver sinusoidal endothelium from cytotoxic conditioning regimens. Accordingly, the incidence of VOD/SOS after reduced-intensity conditioning (RIC) HCT is low compared with myeloablative transplantation, and the natural history, risk factors, and outcomes of VOD/SOS after RIC have not been well characterized. We retrospectively reviewed 1583 consecutive patients receiving RIC HCT at the Dana-Farber Cancer Institute between 2007 and 2017 and ascertained 26 cases of VOD/SOS. The median day of VOD/SOS onset was 26 days (range, 5 to 48) and the cumulative incidence at day 50 was 1.6% (95% confidence interval [CI], 1.1% to 2.4%). Day 100 nonrelapse mortality rate was 23% in the VOD/SOS cohort compared with 6.4% in patients without VOD/SOS (P = .006). Cumulative incidence of VOD/SOS at day 50 was 3.1% after RIC regimen with Flu/Bu2 ± ATG (fludarabine with two doses of busulfan, total dose 6.4 mg/kg, with or without anti-thymocyte globulin), compared with 0.15% after Flu/Bu1 ± ATG (fludarabine with single busulfan dose 3.2 mg/kg, with or without anti-thymocyte globulin) (P = .0002); the incidence rate was 2.1% after RIC HCT with sirolimus-containing graft-versus-host disease prophylaxis, compared with 0.8% for RIC without sirolimus (P = .06). Significant risk factors identified in multivariable analysis for the development of VOD/SOS were sirolimus use (hazard ratio [HR], 5.1; 95% CI, 1.8 to 14.2; P = .002) and RIC regimen with Flu/Bu2 ± ATG (HR, 34; 95% CI, 4.5 to 252; P < .001) or other (HR, 32; 95% CI, 3.9 to 257; P = .001) compared with Flu/Bu1 ± ATG. Rising serum tacrolimus or sirolimus levels, new acute kidney injury, and increasing platelet transfusion requirements were significant early predictors of onset in the week preceding prior VOD/SOS diagnosis. When compared with a previously published cohort of 76 patients with VOD/SOS who developed VOD/SOS after myeloablative HCT in the same time period, VOD/SOS after RIC occurred later and was associated with a lower peak bilirubin level and better overall survival. The variability in presenting features for RIC VOD/SOS highlights the importance of maintaining a high index of suspicion for this entity in RIC HCT.

Haemophagocytic lymphohistiocytosis complicating pembrolizumab treatment for metastatic breast cancer in a patient with the PRF1A91V gene polymorphism.

BACKGROUND: Immune checkpoint inhibitor therapy is a modern breakthrough in medical oncology, but it can precipitate inflammatory and autoimmune adverse effects. Among the most serious of these toxicities is haemophagocytic lymphohistiocytosis (HLH), a life-threatening disorder of unbridled immune activation that results in injury to multiple organ systems. OBJECTIVE: Description of a case of pembrolizumab-associated HLH in a patient with a proposed underlying genetic risk factor for its occurrence. METHODS AND RESULTS: We describe a patient with aggressive metastatic breast cancer who developed HLH while undergoing experimental treatment with pembrolizumab, resulting in critical illness and multiorgan system failure. Pembrolizumab discontinuation and high-dose corticosteroids were effective in managing HLH. Subsequent next-generation sequencing of 15 genes associated with HLH revealed a germline polymorphism in perforin-1 (PRF1), PRFA91V, that may have predisposed the patient to develop HLH. The patient has had no evidence of malignancy for 2 years following recovery despite receiving no further cancer-directed treatment. CONCLUSIONS: HLH is a rare but serious complication of immune checkpoint blockade. Patients with underlying hypomorphic alleles in PRF1 may be predisposed to develop this toxicity. Further studies are necessary to confirm a possible link between perforin gene mutations and immune checkpoint blockade-associated HLH.

Early Clinical Predictors of Hepatic Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome after Myeloablative Stem Cell Transplantation.

Hepatic veno-occlusive disease (VOD), or sinusoidal obstruction syndrome (SOS), is a serious complication of hematopoietic stem cell transplantation (HSCT) with mortality in its severe form exceeding 80%. Although the incidence of VOD/SOS has fallen with contemporary transplantation practices, the increasing use of inotuzumab, the return of gemtuzumab, and the popularity of pharmacokinetic-guided high-dose busulfan may impact incidence. Early intervention with defibrotide improves survival, but prompt diagnosis can be difficult. We aimed to identify clinical parameters that could aid in early detection of VOD/SOS in a large, retrospective, cohort study. Of the 1823 adult patients who underwent myeloablative HSCT between 1996 and 2015 in our center, 205 (11%) developed VOD/SOS, with a median onset of day +14. We compared parameters in the 7 days preceding VOD/SOS onset for cases to 447 randomly selected control subjects in an analogous time frame to determine those with predictive value. Between 7 days before and the day of diagnosis, VOD/SOS patients had higher serum creatinine levels and were more likely to develop acute kidney injury (61% versus 33%, P < .0001), more commonly experienced refractoriness to platelet transfusion (48% versus 24%, P < .0001), and had higher trough serum tacrolimus levels (7 days before VOD/SOS onset: median 8.8 versus 7.3, P = .0002; day of onset: median 9.3 versus 7.2, P < .0001) compared with control subjects. Acute renal dysfunction, platelet refractoriness, and elevated or abnormal tacrolimus levels are dynamic clinical markers that should alert clinicians to the development of VOD/SOS before the presence of classical diagnostic criteria. Using these clinical features to recognize VOD/SOS earlier in its clinical course could promote earlier treatment and lead to improved outcomes of this potentially serious complication.

Antibodies targeting surface membrane antigens in patients with chronic graft-versus-host disease.

Chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic stem cell transplant reflects a complex immune response resulting in chronic damage to multiple tissues. Previous studies indicated that donor B cells and the antibodies they produce play an important role in the development of cGVHD. To understand the pathogenic role of antibodies in cGVHD, we focused our studies on posttransplant production of immunoglobulin G antibodies targeting cell surface antigens expressed in multiple cGVHD affected tissues, due to their potential functional impact on living cells in vivo. Using plate-bound cell membrane proteins as targets, we detected a significantly higher level of antibodies reactive with these membrane antigens in patients who developed cGVHD, compared with those who did not and healthy donors. Plasma-reactive antibody levels increased significantly prior to the clinical diagnosis of cGVHD and were reduced following cGVHD therapies including prednisone, interleukin-2, or extracorporeal photophoresis. Using cell-based immunoprecipitation with plasma from cGVHD patients and mass spectrometry, we identified 43 membrane proteins targeted by these antibodies. The presence of antibodies in cGVHD patients' plasma that specifically target 6 of these proteins was validated. Antibodies reactive with these 6 antigens were more frequently detected in patients with cGVHD compared with patients without cGVHD and healthy donors. These results indicate that antibodies that target membrane antigens of living cells frequently develop in cGVHD patients and further support a role for B cells and antibodies in the development of cGVHD.

A Comparison of the Myeloablative Conditioning Regimen Fludarabine/Busulfan with Cyclophosphamide/Total Body Irradiation, for Allogeneic Stem Cell Transplantation in the Modern Era: A Cohort Analysis.

With improvement in transplantation practices in the modern era, nonrelapse mortality (NRM) following allogeneic hematopoietic stem cell transplantation (HSCT) has improved, while disease relapse rates have remained unchanged. Survival outcomes are therefore driven by NRM in the modern era. Myeloablative conditioning (MAC) regimens are used to maximize disease control and facilitate engraftment; however, their use is often limited by toxicity. The commonly used MAC regimens incorporate either chemotherapy plus total body irradiation (TBI) or combination chemotherapy. Furthermore, reduced-toxicity myeloablative (RTM) regimens, such as fludarabine/busulfan (FluBu), have emerged as alternatives to traditional MAC and their impact on outcomes in the current era have not been fully investigated. In this study, we compare outcomes following HSCT, using the chemotherapy only RTM MAC regimens FluBu with the chemoradiotherapy regimen cyclophosphamide/TBI (CyTBI), for patients with hematologic malignancies who underwent MAC HSCT at the Dana-Farber Cancer Institute. We hypothesized that the chemotherapy-only regimen would fare better, primarily due to improved NRM. A retrospective cohort analysis was performed on 387 patients with myeloid or lymphoid hematologic malignancies who underwent HLA-matched related (8/8), matched unrelated (8/8), or single-antigen mismatched unrelated (7/8) HSCT following myeloablative conditioning. Patients received FluBu (n = 158) or CyTBI (n = 229). The primary outcome was overall survival (OS) and all other outcomes were regarded as secondary. A subset analysis was performed for patients <55 years of age and for acute myelogenous leukemia/myelodysplastic syndrome patients of age <55 years. For the whole cohort, 3-year OS was similar for FluBu compared with CyTBI in unadjusted analysis. However, in multivariable analysis, FluBu resulted in superior OS compared with CyTBI (3-year adjusted estimate: 65% versus 55%, respectively; HR for death, .62; 95% CI, .40 to .97; P = .036). While relapse rates were similar between the 2 regimens, NRM and acute graft-versus-host disease (GVHD) (grade II to IV) were significantly worse with CyTBI compared with FluBu. Rates of chronic GVHD were similar between 2 regimens. These results were consistent in a subset of patients <55 years of age and in acute myelogenous leukemia/myelodysplastic syndrome patients below 55 years of age. The RTM chemotherapy-only regimen FluBu appears to be as effective and more tolerable than the chemoradiotherapy regimen CyTBI, leading to better OS driven by better NRM. The improvement in NRM was attributable chiefly to lower rates of grade II to IV acute GVHD. Relapse rates were not increased with FluBu. In the absence of randomized data, FluBu appears to be the optimal regimen for myeloablative HSCT in patients of all age groups.