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.

Mechanisms of response and resistance to combined decitabine and ipilimumab for advanced myeloid disease.

The challenge of eradicating leukemia in patients with acute myelogenous leukemia (AML) after initial cytoreduction has motivated modern efforts to combine synergistic active modalities including immunotherapy. Recently, the ETCTN/CTEP 10026 study tested the combination of the DNA methyltransferase inhibitor decitabine together with the immune checkpoint inhibitor ipilimumab for AML/myelodysplastic syndrome (MDS) either after allogeneic hematopoietic stem cell transplantation (HSCT) or in the HSCT-naïve setting. Integrative transcriptome-based analysis of 304 961 individual marrow-infiltrating cells for 18 of 48 subjects treated on study revealed the strong association of response with a high baseline ratio of T to AML cells. Clinical responses were predominantly driven by decitabine-induced cytoreduction. Evidence of immune activation was only apparent after ipilimumab exposure, which altered CD4+ T-cell gene expression, in line with ongoing T-cell differentiation and increased frequency of marrow-infiltrating regulatory T cells. For post-HSCT samples, relapse could be attributed to insufficient clearing of malignant clones in progenitor cell populations. In contrast to AML/MDS bone marrow, the transcriptomes of leukemia cutis samples from patients with durable remission after ipilimumab monotherapy showed evidence of increased infiltration with antigen-experienced resident memory T cells and higher expression of CTLA-4 and FOXP3. Altogether, activity of combined decitabine and ipilimumab is impacted by cellular expression states within the microenvironmental niche of leukemic cells. The inadequate elimination of leukemic progenitors mandates urgent development of novel approaches for targeting these cell populations to generate long-lasting responses. This trial was registered at www.clinicaltrials.gov as #NCT02890329.

Memory-like NK cells armed with a neoepitope-specific CAR exhibit potent activity against NPM1 mutated acute myeloid leukemia.

Acute myeloid leukemia (AML) remains a therapeutic challenge, and a paucity of tumor-specific targets has significantly hampered the development of effective immune-based therapies. Recent paradigm-changing studies have shown that natural killer (NK) cells exhibit innate memory upon brief activation with IL-12 and IL-18, leading to cytokine-induced memory-like (CIML) NK cell differentiation. CIML NK cells have enhanced antitumor activity and have shown promising results in early phase clinical trials in patients with relapsed/refractory AML. Here, we show that arming CIML NK cells with a neoepitope-specific chimeric antigen receptor (CAR) significantly enhances their antitumor responses to nucleophosphmin-1 (NPM1)-mutated AML while avoiding off-target toxicity. CIML NK cells differentiated from peripheral blood NK cells were efficiently transduced to express a TCR-like CAR that specifically recognizes a neoepitope derived from the cytosolic oncogenic NPM1-mutated protein presented by HLA-A2. These CAR CIML NK cells displayed enhanced activity against NPM1-mutated AML cell lines and patient-derived leukemic blast cells. CAR CIML NK cells persisted in vivo and significantly improved AML outcomes in xenograft models. Single-cell RNA sequencing and mass cytometry analyses identified up-regulation of cell proliferation, protein folding, immune responses, and major metabolic pathways in CAR-transduced CIML NK cells, resulting in tumor-specific, CAR-dependent activation and function in response to AML target cells. Thus, efficient arming of CIML NK cells with an NPM1-mutation-specific TCR-like CAR substantially improves their innate antitumor responses against an otherwise intracellular mutant protein. These preclinical findings justify evaluating this approach in clinical trials in HLA-A2+ AML patients with NPM1c mutations.

Impact of diagnostic genetics on remission MRD and transplantation outcomes in older patients with AML.

Older patients with acute myeloid leukemia (AML) have high relapse risk and poor survival after allogeneic hematopoietic cell transplantation (HCT). Younger patients may receive myeloablative conditioning to mitigate relapse risk associated with high-risk genetics or measurable residual disease (MRD), but older adults typically receive reduced-intensity conditioning (RIC) to limit toxicity. To identify factors that drive HCT outcomes in older patients, we performed targeted mutational analysis (variant allele fraction ≥2%) on diagnostic samples from 295 patients with AML aged ≥60 years who underwent HCT in first complete remission, 91% of whom received RIC, and targeted duplex sequencing at remission in a subset comprising 192 patients. In a multivariable model for leukemia-free survival (LFS) including baseline genetic and clinical variables, we defined patients with low (3-year LFS, 85%), intermediate (55%), high (35%), and very high (7%) risk. Before HCT, 79.7% of patients had persistent baseline mutations, including 18.3% with only DNMT3A or TET2 (DT) mutations and 61.4% with other mutations (MRD positive). In univariable analysis, MRD positivity was associated with increased relapse and inferior LFS, compared with DT and MRD-negative mutations. However, in a multivariable model accounting for baseline risk, MRD positivity had no independent impact on LFS, most likely because of its significant association with diagnostic genetic characteristics, including MDS-associated gene mutations, TP53 mutations, and high-risk karyotype. In summary, molecular associations with MRD positivity and transplant outcomes in older patients with AML are driven primarily by baseline genetics, not by mutations present in remission. In this group of patients, where high-intensity conditioning carries substantial risk of toxicity, alternative approaches to mitigating MRD-associated relapse risk are needed.

BET-bromodomain and EZH2 inhibitor-treated chronic GVHD mice have blunted germinal centers with distinct transcriptomes.

Despite advances in the field, chronic graft-versus-host-disease (cGVHD) remains a leading cause of morbidity and mortality following allogenic hematopoietic stem cell transplant. Because treatment options remain limited, we tested efficacy of anticancer, chromatin-modifying enzyme inhibitors in a clinically relevant murine model of cGVHD with bronchiolitis obliterans (BO). We observed that the novel enhancer of zeste homolog 2 (EZH2) inhibitor JQ5 and the BET-bromodomain inhibitor JQ1 each improved pulmonary function; impaired the germinal center (GC) reaction, a prerequisite in cGVHD/BO pathogenesis; and JQ5 reduced EZH2-mediated H3K27me3 in donor T cells. Using conditional EZH2 knockout donor cells, we demonstrated that EZH2 is obligatory for the initiation of cGVHD/BO. In a sclerodermatous cGVHD model, JQ5 reduced the severity of cutaneous lesions. To determine how the 2 drugs could lead to the same physiological improvements while targeting unique epigenetic processes, we analyzed the transcriptomes of splenic GCB cells (GCBs) from transplanted mice treated with either drug. Multiple inflammatory and signaling pathways enriched in cGVHD/BO GCBs were reduced by each drug. GCBs from JQ5- but not JQ1-treated mice were enriched for proproliferative pathways also seen in GCBs from bone marrow-only transplanted mice, likely reflecting their underlying biology in the unperturbed state. In conjunction with in vivo data, these insights led us to conclude that epigenetic targeting of the GC is a viable clinical approach for the treatment of cGVHD, and that the EZH2 inhibitor JQ5 and the BET-bromodomain inhibitor JQ1 demonstrated clinical potential for EZH2i and BETi in patients with cGVHD/BO.

HLA-haploidentical vs matched unrelated donor transplants with posttransplant cyclophosphamide-based prophylaxis.

Posttransplant cyclophosphamide (PTCy) graft-versus-host disease (GVHD) prophylaxis has enabled haploidentical (Haplo) transplantation to be performed with results similar to those after matched unrelated donor (MUD) transplantation with traditional prophylaxis. The relative value of transplantation with MUD vs Haplo donors when both groups receive PTCy/calcineurin inhibitor/mycophenolate GVHD prophylaxis is not known. We compared outcomes after 2036 Haplo and 284 MUD transplantations with PTCy GVHD prophylaxis for acute leukemia or myelodysplastic syndrome in adults from 2011 through 2018. Cox regression models were built to compare outcomes between donor types. Recipients of myeloablative and reduced-intensity regimens were analyzed separately. Among recipients of reduced-intensity regimens, 2-year graft failure (3% vs 11%), acute grades 2 to 4 GVHD (hazards ratio [HR], 0.70; P = .022), acute grades 3 and 4 GVHD (HR, 0.41; P = .016), and nonrelapse mortality (HR, 0.43; P = .0008) were lower after MUD than with Haplo donor transplantation. Consequently, disease-free (HR, 0.74; P = .008; 55% vs 41%) and overall (HR, 0.65; P = .001; 67% vs 54%) survival were higher with MUD than with Haplo transplants. Among recipients of myeloablative regimens, day-100 platelet recovery (95% vs 88%) was higher and grades 3 and 4 acute (HR, 0.39; P = .07) and chronic GVHD (HR, 0.66; P = .05) were lower after MUD than with Haplo donor transplantation. There were no differences in graft failure, relapse, nonrelapse mortality, and disease-free and overall survival between donor types with myeloablative conditioning regimens. These data extend and confirm the importance of donor-recipient HLA matching for allogeneic transplantation. A MUD is the preferred donor, especially for transplantations with reduced-intensity conditioning regimens.

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.

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

Allogeneic hematopoietic cell transplantation (alloHCT) can potentially salvage large B-cell lymphoma (LBCL) patients experiencing treatment failure after chimeric antigen receptor T-cell therapy (CAR T). Nonetheless, data on the efficacy and toxicities of alloHCT after receipt of CAR T are limited. We report a multicenter retrospective study assessing the safety, toxicities, and outcomes of alloHCT in LBCL patients following CAR T failure. Eighty-eight patients with relapsed, refractory LBCL received an alloHCT following anti-CD19 CAR T failure. The median number of lines of therapy between CAR T infusion and alloHCT was one (range, 0-7). Low intensity conditioning was used in 77% (n=68) and peripheral blood was the most common graft source (86%, n=76). The most common donor types were matched unrelated donor (39%), followed by haploidentical (30%) and matched related donor (26%). Median follow-up of survivors was 15 months (range, 1-72). One-year overall survival, progression-free survival, and graft-versus-host disease-free relapse-free survival were 59%, 45%, and 39% respectively. One-year non-relapse mortality and progression/relapse were 22% and 33% respectively. On multivariate analysis, <2 lines of intervening therapy between CAR T and alloHCT and complete response at time of alloHCT were associated with better outcomes. In conclusion, alloHCT after CAR T failure can provide durable remissions in a subset of patients.

Inhibition of inositol kinase B controls acute and chronic graft-versus-host disease.

T-cell activation releases inositol 1,4,5-trisphosphate (IP3), inducing cytoplasmic calcium (Ca2+) influx. In turn, inositol 1,4,5-trisphosphate 3-kinase B (Itpkb) phosphorylates IP3 to negatively regulate and thereby tightly control Ca2+ fluxes that are essential for mature T-cell activation and differentiation and protection from cell death. Itpkb pathway inhibition increases intracellular Ca2+, induces apoptosis of activated T cells, and can control T-cell-mediated autoimmunity. In this study, we employed genetic and pharmacological approaches to inhibit Itpkb signaling as a means of controlling graft-versus-host disease (GVHD). Murine-induced, Itpkb-deleted (Itpkb-/-) T cells attenuated acute GVHD in 2 models without eliminating A20-luciferase B-cell lymphoma graft-versus-leukemia (GVL). A highly potent, selective inhibitor, GNF362, ameliorated acute GVHD without impairing GVL against 2 acute myeloid leukemia lines (MLL-AF9-eGFP and C1498-luciferase). Compared with FK506, GNF362 more selectively deleted donor alloreactive vs nominal antigen-responsive T cells. Consistent with these data and as compared with FK506, GNF362 had favorable acute GVHD and GVL properties against MLL-AF9-eGFP cells. In chronic GVHD preclinical models that have a pathophysiology distinct from acute GVHD, Itpkb-/- donor T cells reduced active chronic GVHD in a multiorgan system model of bronchiolitis obliterans (BO), driven by germinal center reactions and resulting in target organ fibrosis. GNF362 treatment reduced active chronic GVHD in both BO and scleroderma models. Thus, intact Itpkb signaling is essential to drive acute GVHD pathogenesis and sustain active chronic GVHD, pointing toward a novel clinical application to prevent acute or treat chronic GVHD.

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.

Randomized controlled trial of geriatric consultation versus standard care in older adults with hematologic malignancies.

We conducted a randomized controlled trial in older adults with hematologic malignancies to determine the impact of geriatrician consultation embedded in our oncology clinic alongside standard care. From February 2015 to May 2018, transplant-ineligible patients aged ≥75 years who presented for initial consultation for lymphoma, leukemia, or multiple myeloma at Dana-Farber Cancer Institute (Boston, MA, USA) were eligible. Pre-frail and frail patients, classified based on phenotypic and deficit-accumulation approaches, were randomized to receive either standard oncologic care with or without consultation with a geriatrician. The primary outcome was 1-year overall survival. Secondary outcomes included unplanned care utilization within 6 months of follow-up and documented end-of-life (EOL) goals-of-care discussions. Clinicians were surveyed as to their impressions of geriatric consultation. One hundred sixty patients were randomized to either geriatric consultation plus standard care (n=60) or standard care alone (n=100). The median age of the patients was 80.4 years (standard deviation = 4.2). Of those randomized to geriatric consultation, 48 (80%) completed at least one visit with a geriatrician. Consultation did not improve survival at 1 year compared to standard care (difference: 2.9%, 95% confidence interval: -9.5% to 15.2%, P=0.65), and did not significantly reduce the incidence of emergency department visits, hospital admissions, or days in hospital. Consultation did improve the odds of having EOL goals-of-care discussions (odds ratio = 3.12, 95% confidence interval: 1.03 to 9.41) and was valued by surveyed hematologic-oncology clinicians, with 62.9%-88.2% of them rating consultation as useful in the management of several geriatric domains.

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).

Association of Polypharmacy and Potentially Inappropriate Medications With Frailty Among Older Adults With Blood Cancers.

BACKGROUND: Polypharmacy and potentially inappropriate medications (PIMs) are common among older adults with blood cancers, but their association with frailty and how to manage them optimally remain unclear. PATIENTS AND METHODS: From 2015 to 2019, patients aged ≥75 years presenting for initial oncology consult underwent screening geriatric assessment. Patients were determined to be robust, prefrail, or frail via deficit accumulation and phenotypic approaches. We quantified each patient's total number of medications and PIMs using the Anticholinergic Risk Scale (ARS) and a scale we generated using the NCCN Medications of Concern called the Geriatric Oncology Potentially Inappropriate Medications (GO-PIM) scale. We assessed cross-sectional associations of PIMs with frailty in multivariable regression models adjusting for age, gender, and comorbidity. RESULTS: Of 785 patients assessed, 603 (77%) were taking ≥5 medications and 421 (54%) were taking ≥8 medications; 201 (25%) were taking at least 1 PIM based on the ARS and 343 (44%) at least 1 PIM based on the GO-PIM scale. Among the 468 (60%) patients on active cancer treatment, taking ≥8 medications was associated with frailty (adjusted odds ratio [aOR], 2.82; 95% CI, 1.92-4.17). With each additional medication, the odds of being prefrail or frail increased 8% (aOR, 1.08; 95% CI, 1.04-1.12). With each 1-point increase on the ARS, the odds of being prefrail or frail increased 19% (aOR, 1.19; 95% CI, 1.03-1.39); with each additional PIM based on the GO-PIM scale, the odds increased 65% (aOR, 1.65; 95% CI, 1.34-2.04). CONCLUSIONS: Polypharmacy and PIMs are prevalent among older patients with blood cancers; taking ≥8 medications is strongly associated with frailty. These data suggest careful medication reconciliation for this population may be helpful, and deprescribing when possible is high-yield, especially for PIMs on the GO-PIM scale.

Gait speed, grip strength, and clinical outcomes in older patients with hematologic malignancies.

This study aimed to evaluate whether gait speed and grip strength predicted clinical outcomes among older adults with blood cancers. We prospectively recruited 448 patients aged 75 years and older presenting for initial consultation at the myelodysplastic syndrome/leukemia, myeloma, or lymphoma clinic of a large tertiary hospital, who agreed to assessment of gait and grip. A subset of 314 patients followed for ≥6 months at local institutions was evaluated for unplanned hospital or emergency department (ED) use. We used Cox proportional hazard models calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for survival, and logistic regression to calculate odds ratios (ORs) for hospital or ED use. Mean age was 79.7 (± 4.0 standard deviation) years. After adjustment for age, sex, Charlson comorbidity index, cognition, treatment intensity, and cancer aggressiveness/type, every 0.1-m/s decrease in gait speed was associated with higher mortality (HR, 1.20; 95% CI, 1.12-1.29), odds of unplanned hospitalizations (OR, 1.33; 95% CI, 1.16-1.51), and ED visits (OR, 1.34; 95% CI, 1.17-1.53). Associations held among patients with good Eastern Cooperative Oncology Group performance status (0 or 1). Every 5-kg decrease in grip strength was associated with worse survival (adjusted HR, 1.24; 95% CI, 1.07-1.43) but not hospital or ED use. A model with gait speed and all covariates had comparable predictive power to comprehensive validated frailty indexes (phenotype and cumulative deficit) and all covariates. In summary, gait speed is an easily obtained "vital sign" that accurately identifies frailty and predicts outcomes independent of performance status among older patients with blood cancers.

Small-molecule BCL6 inhibitor effectively treats mice with nonsclerodermatous chronic graft-versus-host disease.

Patient outcomes for steroid-dependent or -refractory chronic graft-versus-host diesease (cGVHD) are poor, and only ibrutinib has been US Food and Drug Administration (FDA) approved for this indication. cGVHD is often driven by the germinal center (GC) reaction, in which T follicular helper cells interact with GC B cells to produce antibodies that are associated with disease pathogenesis. The transcriptional corepressor B-cell lymphoma 6 (BCL6) is a member of the Broad-complex, Tramtrack, and Bric-abrac/poxvirus and zinc finger (BTB/POZ) transcription factor family and master regulator of the immune cells in the GC reaction. We demonstrate that BCL6 expression in both donor T cells and B cells is necessary for cGVHD development, pointing to BCL6 as a therapeutic cGVHD target. A small-molecule BCL6 inhibitor reversed active cGVHD in a mouse model of multiorgan system injury with bronchiolitis obliterans associated with a robust GC reaction, but not in cGVHD mice with scleroderma as the prominent manifestation. For cGVHD patients with antibody-driven cGVHD, targeting of BCL6 represents a new approach with specificity for a master GC regulator that would extend the currently available second-line agents.

Cytomegalovirus events in high-risk allogeneic hematopoietic-cell transplantation patients who received letermovir prophylaxis.

Letermovir is approved for the prevention of cytomegalovirus (CMV) reactivation and clinical disease in patients undergoing allogeneic hematopoietic-cell transplantation (HCT). However, there is uncertainty about letermovir's ability to prevent clinical events during the period of prophylaxis as well as after the discontinuation of prophylaxis in the post-transplant setting. We performed a retrospective cohort study in CMV-seropositive allogeneic HCT recipients at high risk of CMV events, who received letermovir for primary prophylaxis from November 2017 through December 2019. We analyzed CMV outcomes for these patients during and after prophylaxis was discontinued. Patient outcomes were followed through June 2020. Sixty patients received letermovir for a median of 13 weeks (range, 1-72 weeks). Thirteen (22%) patients had quantifiable CMV DNAemia (reactivation) during letermovir prophylaxis a median of 9 days (range, 1-59 days) after starting letermovir. Five (8%) of these patients discontinued prophylaxis and received preemptive therapy (PET) with valganciclovir; eight (13%) continued letermovir as prophylaxis and CMV DNAemia resolved without PET. Thirteen patients (22%) had post-prophylaxis CMV reactivation a median of 33 days (range, 14-109 days) after letermovir discontinuation. In four (7%) of these patients, CMV DNAemia resolved without PET, and nine (15%) received PET. No patient developed CMV disease. Patients who developed CMV reactivation during prophylaxis did so shortly after initiation of letermovir, and most patients who developed CMV reactivation post-prophylaxis did so within 60 days after discontinuation of letermovir. Letermovir prophylaxis has changed the presentation of CMV infection in high-risk HCT patients.

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.

Pooled analysis of Day 100 survival for defibrotide-treated patients with hepatic veno-occlusive disease/sinusoidal obstruction syndrome and ventilator or dialysis dependence following haematopoietic cell transplantation.

For patients with untreated hepatic veno-occlusive disease (VOD)/sinusoidal obstruction syndrome (SOS) with multi-organ dysfunction (MOD), mortality is >80%. We conducted a pooled analysis of three studies that assessed Day 100 survival in relationship to MOD severity, with dialysis and/or ventilator dependence representing the most severe organ dysfunction. All patients in the analysis were diagnosed using Baltimore criteria/biopsy. This analysis of patients with VOD/SOS and MOD after haematopoietic cell transplantation (HCT; n = 651) demonstrated higher Day 100 survival rates amongst defibrotide-treated patients with VOD/SOS with less versus more severe forms of MOD. Even patients with severe forms of MOD post-HCT benefitted from defibrotide.

Tyrosine kinase inhibitors and immune checkpoint blockade in allogeneic hematopoietic cell transplantation.

Advances in the prevention of graft-versus-host disease (GVHD) and opportunistic infection have improved survival after allogeneic hematopoietic cell transplantation (allo-HCT) in the past decade. However, few inroads have been made into the treatment or prevention of relapse of the underlying malignancy for which allo-HCT is being performed. The introduction of US Food and Drug Administration-approved agents with significant activity in a variety of hematologic malignancies provides an opportunity to evaluate these interventions in the allo-HCT setting. Some of the most promising new agents include tyrosine kinase inhibitors (TKIs) directed at bcr-abl, kinase inhibitors targeting fms-like tyrosine kinase 3, and immune checkpoint inhibitors blocking both CTLA4 and PD-1. Data have emerged indicating potential efficacy of these agents in preventing or treating relapse, though definitive evidence remains elusive. However, potential toxicity can be considerable, highlighting the need for further clinical trials to define the therapeutic window. This review explores the immunologic and clinical consequence of treatment with both TKIs and checkpoint inhibitors in the peri- and post-allo-HCT setting.