Multicenter evaluation of the addition of eltrombopag to immunosuppressive therapy for adults with severe aplastic anemia.

Eltrombopag has been shown to improve response rates when added to standard therapy in adults with severe aplastic anemia in controlled trial settings. However, outcomes in real-world populations have mostly been examined in small retrospective studies. This robust, multicenter, retrospective cohort study across six academic health systems compared outcomes in patients who received immunosuppressive therapy with or without eltrombopag. The study included 82 patients who received front-line therapy from January 2014 to August 2021. Overall response rates at 6 months did not differ significantly for patients receiving eltrombopag versus immunosuppressive therapy alone (58% v. 65%, p = 0.56). However, complete response rates at 6 and 12 months were over two times higher in the eltrombopag arm (29% v. 12%, p = 0.06 and 48% v. 18%, p = 0.005). Rates of hepatotoxicity were similar across both arms. Eltrombopag addition did not impact overall survival (median not reached in either arm at 2 years, p = 0.86) or disease-free survival (median not reached v. 13.3 months at 2 years, p = 0.20). Eltrombopag may not produce as large of a benefit in real-world settings compared to controlled trial settings but may offer patients deeper responses with similar rates of toxicity to immunosuppressive therapy alone.

Reducing Lipid Panel Error Allowances to Improve the Accuracy of Cardiovascular Risk Stratification.

BACKGROUND: The standard lipid panel forms the backbone of atherosclerotic cardiovascular disease risk assessment. Suboptimal analytical performance, along with biological variability, could lead to erroneous risk assessment and management decisions. The current National Cholesterol Education Program (NCEP) performance recommendations have remained unchanged for almost 3 decades despite improvements in assay technology. We investigated the potential extent of risk misclassification when the current recommendations are met and explored the impact of improving analytical performance goals. METHODS: We extracted lipid panel data for 8506 individuals from the NHANES database and used these to classify subjects into 4 risk groups as recommended by the 2018 US Multisociety guidelines. Analytical bias and imprecision, at the allowable limits, as well as biological variability, were introduced to the measured values to determine the impact on misclassification. Bias and imprecision were systematically reduced to determine the degree of improvement that may be achieved. RESULTS: Using the current performance recommendations, up to 10% of individuals were misclassified into a different risk group. Improving proportional bias by 1%, and fixing imprecision to 3% across all assays reduced misclassifications by up to 10%. The effect of biological variability can be reduced by taking the average of serial sample measurements. CONCLUSIONS: The current NCEP recommendations for analytical performance of lipid panel assays allow for an unacceptable degree of misclassification, leading to possible mismanagement of cardiovascular disease risk. Iteratively reducing allowable error can improve this.

Waldenström macroglobulinemia with secondary pure red cell aplasia in a patient with metastatic castrate resistant prostate cancer receiving an immune checkpoint inhibitor: a case report.

BACKGROUND: Hypoproliferative anemia is a frequently encountered adverse event in cancer patients receiving immune checkpoint inhibitors (ICI). Secondary pure red cell aplasia (PRCA) is a rare but recognized immune related adverse event. With the burgeoning use of ICIs, the association of secondary PRCA with an underlying lymphoproliferative disorder is often overlooked. CASE PRESENTATION: We report a case of a 67-year-old non-Hispanic Caucasian male with metastatic castrate resistant prostate cancer, who developed severe transfusion dependent anemia with reticulocytopenia while receiving treatment with olaparib and pembrolizumab. His bone marrow findings demonstrated erythroid hypoplasia, in addition to a CD5-negative, CD10-negative monotypic B-cell population and a somatic MYD88L265P mutation. With a presence of an IgM-paraprotein, he was diagnosed with Waldenström macroglobulinemia (WM) with secondary PRCA and treated with 6 cycles of bendamustine and rituximab. He achieved a complete response with this regimen and was transfusion independent. CONCLUSION: In this case, underlying WM was uncovered through systematic investigation of anemia caused by ICI therapy. This report highlights the possibility of a lymphoproliferative disorder in patients with concerns for PRCA with prior ICI exposure. If identified, treating the underlying lymphoproliferative disorder is highly efficacious in the management of the secondary PRCA.

Efficacy of a Dual-Epitope Dendritic Cell Vaccine as Part of Combined Immunotherapy for HER2-Expressing Breast Tumors.

Previous work from our group and others has shown that patients with breast cancer can generate a T cell response against specific human epidermal growth factor 2 (HER2) epitopes. In addition, preclinical work has shown that this T cell response can be augmented by Ag-directed mAb therapy. This study evaluated the activity and safety of a combination of dendritic cell (DC) vaccination given with mAb and cytotoxic therapy. We performed a phase I/II study using autologous DCs pulsed with two different HER2 peptides given with trastuzumab and vinorelbine to a study cohort of patients with HER2-overexpressing and a second with HER2 nonoverexpressing metastatic breast cancer. Seventeen patients with HER2-overexpressing and seven with nonoverexpressing disease were treated. Treatment was well tolerated, with one patient removed from therapy because of toxicity and no deaths. Forty-six percent of patients had stable disease after therapy, with 4% achieving a partial response and no complete responses. Immune responses were generated in the majority of patients but did not correlate with clinical response. However, in one patient, who has survived >14 y since treatment in the trial, a robust immune response was demonstrated, with 25% of her T cells specific to one of the peptides in the vaccine at the peak of her response. These data suggest that autologous DC vaccination when given with anti-HER2-directed mAb therapy and vinorelbine is safe and can induce immune responses, including significant T cell clonal expansion, in a subset of patients.

Phase Ib trial of lenalidomide as post-remission therapy for older adults with acute myeloid leukemia: Safety and longitudinal assessment of geriatric functional domains.

BACKGROUND AND OBJECTIVES: Novel, non-cytotoxic agents are driving a paradigm shift for treatment of older adults with acute myeloid leukemia (AML). Older patients who initially receive intensive cytotoxic induction may choose to not proceed with cytotoxic consolidation therapy. Lenalidomide is an orally-administered immunomodulatory small molecule with activity in AML and a favorable safety profile in older adults with active leukemia. We conducted a phase Ib study of lenalidomide as post-remission therapy in older adults and assessed its impact on geriatric functional domains. MATERIALS AND METHODS: Participants were patients with AML over age 60 years who had undergone induction therapy and were poor candidates for cytotoxic consolidation. Lenalidomide was administered for 28 days in three dose cohorts. A Bayesian dose-escalation method determined cohort assignment and maximum tolerated dose (MTD). Geriatric assessment (GA) was performed before and after the cycle of lenalidomide. RESULTS: Nineteen patients with median age 68 were treated with at least one 28-day course of lenalidomide. Dose-limiting toxicities were observed in three participants at 25 mg, zero participants at 35 mg, and one participant at 50 mg. MTD was 35 mg. Median relapse-free survival was 4.3 months. GA was completed before and after treatment in fifteen patients, demonstrating improved cognitive function and no changes in physical, psychological, or social function after lenalidomide. CONCLUSION: Lenalidomide can be safely administered to older adults with AML with preservation of functional domains important to older patients. Serial GA can be performed in a novel drug study as a tool to characterize treatment tolerability.

Phase II Trial of Pembrolizumab after High-Dose Cytarabine in Relapsed/Refractory Acute Myeloid Leukemia.

Immune suppression, exhaustion, and senescence are frequently seen throughout disease progression in acute myeloid leukemia (AML). We conducted a phase II study of high-dose cytarabine followed by pembrolizumab 200 mg i.v. on day 14 to examine whether PD-1 inhibition improves clinical responses in relapsed/refractory (R/R) AML. Overall responders could receive pembrolizumab maintenance up to 2 years. Among 37 patients enrolled, the overall response rate, composite complete remission (CRc) rate (primary endpoint), and median overall survival (OS) were 46%, 38%, and 11.1 months, respectively. Patients with refractory/early relapse and those receiving treatment as first salvage had encouraging outcomes (median OS, 13.2 and 11.3 months, respectively). Grade ≥3 immune-related adverse events were rare (14%) and self-limiting. Patients who achieved CRc had a higher frequency of progenitor exhausted CD8+ T cells expressing TCF-1 in the bone marrow prior to treatment. A multifaceted correlative approach of genomic, transcriptomic, and immunophenotypic profiling offers insights on molecular correlates of response and resistance to pembrolizumab. SIGNIFICANCE: Immune-checkpoint blockade with pembrolizumab was tolerable and feasible after high-dose cytarabine in R/R AML, with encouraging clinical activity, particularly in refractory AML and those receiving treatment as first salvage regimen. Further study of pembrolizumab and other immune-checkpoint blockade strategies after cytotoxic chemotherapy is warranted in AML.See related commentary by Wei et al., p. 551. This article is highlighted in the In This Issue feature, p. 549.

Safety and Efficacy of Pembrolizumab Prior to Allogeneic Stem Cell Transplantation for Acute Myelogenous Leukemia.

Programmed death 1 (PD-1) is an integral component of acute myelogenous leukemia (AML) immune evasion, chemotherapy resistance, and disease progression. PD-1 inhibitors are being investigated as treatment for AML in combination with hypomethylating agents and cytotoxic chemotherapy with encouraging findings. Although allogeneic stem cell transplantation (alloSCT) remains the most established curative treatment for patients with relapsed and refractory AML in complete remission, there are limited data on the clinical outcomes and safety of immune checkpoint inhibitors (ICIs) prior to alloSCT in AML. In the present study, we compared clinical outcomes of 9 patients with AML receiving high-dose cytarabine followed by pembrolizumab in a phase II clinical trial (NCT02768792) prior to alloSCT versus a historical control group of 18 AML patients who underwent alloSCT without prior ICI exposure. The nonparametric Jonckheere-Terpstra test was used to test for a difference in the ordered severity categories of acute graft-versus-host disease (GVHD) within 100 days of transplantation. Time-to-event estimates for overall survival and relapse-free survival were calculated using the Kaplan-Meier method and compared using a log-rank test. One-year survival was not significantly different between the treatment groups (67% versus 78%; P = .34). 100-day mortality was 0% in the ICI group versus 17% in the control group, and there was no increase in grade III-IV acute GVHD in patients treated with pembrolizumab prior to alloSCT. No chronic GVHD was seen in patients treated with pembrolizumab prior to alloSCT and who received post-transplantation cyclophosphamide (PTCy) as part of their conditioning regimen. These findings reinforce the safety and feasibility of ICI therapy prior to alloSCT in patients with AML, and suggest that PTCy may abrogate GVHD risk and severity in patients who receive ICI prior to undergoing alloSCT for AML.

Risk stratification and outreach to hematology/oncology patients during the COVID-19 pandemic.

PURPOSE: Cancer patients have many medical and psychosocial needs, which may increase during the COVID-19 pandemic. We sought to (1) risk-stratify hematology/oncology patients using general medicine and cancer-specific methods to identify those at high risk for acute care utilization, (2) measure the correlation between two risk stratification methods, and (3) perform a telephone-based needs assessment with intervention for high-risk patients. METHODS: Patients were risk-stratified using a general medical health composite score (HCS) and a cancer-specific risk (CSR) stratification based on disease and treatment characteristics. The correlation between HCS and CSR was measured using Spearman's correlation. A multi-disciplinary team developed a focused needs assessment script with recommended interventions for patients categorized as high-risk by either method. The number of patient needs identified and referrals for services made in the first month of outreach are reported. RESULTS: A total of 1697 patients were risk-stratified, with 17% high-risk using HCS and 22% high-risk using CSR. Correlation between HCS and CSR was modest (ρ = 0.41). During the first month of the pilot, 286 patients were called for outreach with 245 contacted (86%). Commonly identified needs were financial difficulties (17%), uncontrolled symptoms (15%), and interest in advance care planning (13%), resulting in referral for supportive services for 33% of patients. CONCLUSION: There is a high burden of unmet medical and psychosocial needs in hematology/oncology patients during the COVID-19 pandemic. A telephone-based outreach program results in the identification of and intervention for these needs; however, additional cancer-specific risk models are needed to improve targeting to high-risk patients.

Ruxolitinib for the treatment of lymphoma-associated hemophagocytic lymphohistiocytosis: A cautionary tale.

INTRODUCTION: Hemophagocytic lymphohistiocytosis is a hyperinflammatory syndrome characterized by fever, hyperferritinemia, hypertriglyceridemia, hypofibrinogenemia, and pancytopenia. Three publications reported success with ruxolitinib, a Janus-associated kinase (JAK1/2) inhibitor. This therapy interrupts the production of cytokines associated with hemophagocytic lymphohistiocytosis, namely interferon-γ and interleukins 2, 6, and 10. CASE REPORT: We administered ruxolitinib to two patients with lymphoma-associated hemophagocytic lymphohistiocytosis who had failed standard treatment with dexamethasone and etoposide. MANAGEMENT AND OUTCOME: Patient #1 was started on ruxolitinib 10 mg BID, and titrated to 15 mg BID. All but two of the hemophagocytic lymphohistiocytosis criteria resolved within two weeks, and she was able to restart therapy for lymphoma. During her ruxolitinib taper, she again presented with relapsed hemophagocytic lymphohistiocytosis. She was taking 2.5 mg a day at the time. Despite salvage treatment, she died from the disease. Patient #2 was a diffuse large B-cell lymphoma patient who presented with hemophagocytic lymphohistiocytosis and was treated with chemoimmunotherapy and achieved a complete response (CR). Hemophagocytic lymphohistiocytosis symptoms relapsed, and he was treated with ruxolitinib. He developed relapsed lymphoma and unfortunately died. DISCUSSION: While treating the underlying lymphoma is a clear priority, the cytopenias and other symptoms of hemophagocytic lymphohistiocytosis complicate the delivery of this therapy. Hence, the use of ruxolitinib as a bridge to definitive therapy was appealing. However, we are concerned about the progression of lymphoma while these patients were taking ruxolitinib. Ruxolitinib may be controlling cytokine storm associated with hemophagocytic lymphohistiocytosis, while other aspects of the condition are progressing. Therefore, we would advise caution in its use in lymphoma-associated-hemophagocytic lymphohistiocytosis until more data are available.

Dose-related mucositis with hydroxyurea for cytoreduction in acute myeloid leukemia.

Hyperleukocytosis occurs in 15-20% of all newly diagnosed acute myeloid leukemia patients and requires emergent treatment with leukapheresis or hydroxyurea when accompanied by signs or symptoms of leukostasis. Currently, there is no standardized hydroxyurea dosing strategy, although usual dosing ranges from 50 to 150 mg/kg/day, and prescribing patterns vary significantly among oncologists and institutions. In addition to other hematologic and dermatologic toxicities, the use of hydroxyurea may be associated with significant mucositis and mucositis-related pain. The purpose of this study was to compare mucositis-related pain between two different hydroxyurea dosing strategies in patients who received hydroxyurea for cytoreduction during induction. A retrospective chart review of adult patients with acute myeloid leukemia treated with chemotherapy at UNC Medical Center from April 2014 to April 2016 who received at least one dose of hydroxyurea for cytoreduction was conducted. This study compared the safety and toxicity profiles of hydroxyurea in patients who received high-dose hydroxyurea (≥75 mg/kg/day) versus low-dose hydroxyurea (<75 mg/kg/day). Safety and toxicity were evaluated based on indicators of mucositis and cumulative intravenous narcotic requirements following induction chemotherapy. Data collection included baseline demographics, mucositis risk factors, baseline laboratory values, hydroxyurea dosing, mucositis indicators, and pain indicators. A total of 55 patients were included in the study, 21 patients (38.2%) received the high-dose hydroxyurea dosing strategy. The high-dose hydroxyurea dosing strategy had a significantly higher white blood cell count at diagnosis, increased duration of hydroxyurea, and received a higher cumulative dose of hydroxyurea. Additionally, the high-dose hydroxyurea dosing strategy patients were associated with significantly more grade 3 or 4 mucositis requiring a formulation change (0% versus 28.6%, p = 0.002) and significantly higher cumulative intravenous narcotic requirements during induction (p = 0.019). No significant differences in baseline demographics or mucositis risk factors between dosing strategies were identified. The high-dose hydroxyurea dosing strategy patients had a significant increase in cumulative intravenous narcotic requirements and formulation changes, both common interventions made for the treatment of mucositis. Additional studies are needed to further elucidate the safety and toxicity profiles of hydroxyurea dosing strategies and to explore the correlation between total cumulative hydroxyurea dose and total cumulative narcotic requirements.

A Comparison of Clofarabine-based (GCLAC) and Cladribine-based (CLAG) Salvage Chemotherapy for Relapsed/Refractory AML.

BACKGROUND: Salvage regimens for patients with relapsed/refractory acute myeloid leukemia (rrAML) lack comparative data for superiority. Thus, we conducted a retrospective analysis of clofarabine-based (GCLAC; granulocyte colony-stimulating factor [filgrastim], clofarabine, high-dose cytarabine) versus cladribine-based (CLAG; cladribine, cytarabine, granulocyte colony-stimulating factor [filgrastim]) regimens in rrAML. PATIENTS AND METHODS: We identified 41 consecutive patients with rrAML who had received either GCLAC or CLAG from 2011 to 2014. The primary outcome measure was the complete remission (CR) rate defined according to the International Working Group criteria. The secondary outcomes included the proportion of patients who underwent allogenic stem cell transplantation and the rate of relapse-free survival and overall survival. RESULTS: We found no significant differences in the baseline characteristics of the patients treated with GCLAC (n = 22) or CLAG (n = 19). The outcomes with these 2 regimens were not significantly different. Patients treated with GCLAC had a CR/CR with incomplete blood count recovery rate of 64% compared with 47% for the patients treated with CLAG (P = .36). Of the GCLAC patients, 45% underwent allogeneic stem cell transplantation compared with 26% of the CLAG patients (P = .32). The median relapse-free survival after GCLAC and CLAG was 1.59 years and 1.03 years, respectively (P = .75). The median overall survival after GCLAG and CLAG was 1.03 years and 0.70 years, respectively (P = .08). The drug costs were significantly different for GCLAC versus CLAG. Using an average wholesale price, the cost per patient per cycle was $60,821.60 for GCLAC and $4910.60 for CLAG. CONCLUSION: A single-institutional retrospective analysis found no significant differences in the outcomes between GCLAC and CLAG for rrAML patients, although formal comparisons should be performed in a randomized clinical trial. The cost of GCLAC was greater than that of CLAG, which should be considered when evaluating the choice for the salvage chemotherapy options.

CUSUM-Logistic Regression analysis for the rapid detection of errors in clinical laboratory test results.

OBJECTIVE: The main drawback of the periodic analysis of quality control (QC) material is that test performance is not monitored in time periods between QC analyses, potentially leading to the reporting of faulty test results. The objective of this study was to develop a patient based QC procedure for the more timely detection of test errors. METHOD: Results from a Chem-14 panel measured on the Beckman LX20 analyzer were used to develop the model. Each test result was predicted from the other 13 members of the panel by multiple regression, which resulted in correlation coefficients between the predicted and measured result of >0.7 for 8 of the 14 tests. A logistic regression model, which utilized the measured test result, the predicted test result, the day of the week and time of day, was then developed for predicting test errors. The output of the logistic regression was tallied by a daily CUSUM approach and used to predict test errors, with a fixed specificity of 90%. RESULTS: The mean average run length (ARL) before error detection by CUSUM-Logistic Regression (CSLR) was 20 with a mean sensitivity of 97%, which was considerably shorter than the mean ARL of 53 (sensitivity 87.5%) for a simple prediction model that only used the measured result for error detection. CONCLUSION: A CUSUM-Logistic Regression analysis of patient laboratory data can be an effective approach for the rapid and sensitive detection of clinical laboratory errors.

C-C chemokine receptor 5 on pulmonary mesenchymal cells promotes experimental metastasis via the induction of erythroid differentiation regulator 1.

UNLABELLED: C-C Chemokine receptor 5 knockout (Ccr5(-/-)) mice develop fewer experimental pulmonary metastases than wild-type (WT) mice. This phenomenon was explored by applying gene expression profiling to the lungs of mice with these metastases. Consequently, erythroid differentiation regulator 1 (Erdr1) was identified as upregulated in the WT mice. Though commonly associated with bone marrow stroma, Erdr1 was differentially expressed in WT pulmonary mesenchymal cells (PMC) and murine embryonic fibroblasts (MEF). Moreover, the Ccr5 ligand Ccl4 increased its expression by 3.36 ± 0.14-fold. Ccr5 signaling was dependent on the mitogen-activated protein kinase kinase (Map2k) but not the phosphoinositide 3-kinase (Pi3k) pathway because treatment with U0126 inhibited upregulation of Erdr1, but treatment with LY294002 increased the expression by 3.44 ± 0.92-fold (P < 0.05). The effect Erdr1 on B16-F10 melanoma metastasis was verified by the adoptive transfer of WT MEFs into Ccr5(-/-) mice. In this model, MEFs that had been transduced with Erdr1 short hairpin RNA (shRNA) lowered metastasis by 33% compared with control transduced MEFs. The relevance of ERDR1 on human disease was assessed by coculturing chronic lymphocytic leukemia (CLL) cells with M2-10B4 stromal cells that had been transfected with shRNA or control plasmids. After 96 hours of coculture, the cell counts were higher with control cell lines than with Erdr1 knockdown lines [odds ratio (OR), 1.88 ± 0.27, 2.52 ± 0.66, respectively]. This increase was associated with a decrease in apoptotic cells (OR, 0.69 ± 0.18, 0.58 ± 0.12, respectively). IMPLICATIONS: Therefore, ERDR1 is a stromal-derived factor that promotes cancer cell survival in vitro and in an experimental metastasis model.

CC chemokine receptor 8 potentiates donor Treg survival and is critical for the prevention of murine graft-versus-host disease.

The infusion of donor regulatory T cells (Tregs) has been used to prevent acute graft-versus-host disease (GVHD) in mice and has shown promise in phase 1 clinical trials. Previous work suggested that early Treg migration into lymphoid tissue was important for GVHD prevention. However, it is unclear how and where Tregs function longitudinally to affect GVHD. To better understand their mechanism of action, we studied 2 Treg-associated chemokine receptors in murine stem cell transplant models. CC chemokine receptor (CCR) 4 was dispensable for donor Treg function in the transplant setting. Donor Tregs lacking CCR8 (CCR8(-/-)), however, were severely impaired in their ability to prevent lethal GVHD because of increased cell death. By itself, CCR8 stimulation was unable to rescue Tregs from apoptosis. Instead, CCR8 potentiated Treg survival by promoting critical interactions with dendritic cells. In vivo, donor bone marrow-derived CD11c(+) antigen-presenting cells (APCs) were important for promoting donor Treg maintenance after transplant. In contrast, host CD11c(+) APCs appeared to be dispensable for early activation and expansion of donor Tregs. Collectively, our data indicate that a sustained donor Treg presence is critical for their beneficial properties, and that their survival depends on CCR8 and donor but not host CD11c(+) APCs.

The association of 25 hydroxyvitamin D and parathyroid hormone with metabolic syndrome in two ethnic groups in South Africa.

INTRODUCTION: Though inconsistent, a number of studies have shown an association between vitamin D (25(OH)D) status, parathyroid hormone (PTH) and the metabolic syndrome (Met S). These have largely been carried out in Caucasians or black subjects living in high income countries. There no data on the relationship of 25(OH)D and PTH status with Met S in populations resident in Africa. The aims of this study were to evaluate if there was an association of 25(OH)D or PTH with Met S in non-Caucasian populations in South Africa, and whether these molecules explained ethnic differences in the prevalence of Met S and its individual components. METHODS: We measured anthropometry, serum 25(OH)D and PTH levels and the components of Met S, plus related metabolic variables, in 374 African and 350 Asian Indian healthy adults from the greater Johannesburg metropolitan area. RESULTS: Met S was diagnosed in 29% of the African and 46% of the Asian Indian subjects (p<0.0001). Subjects with Met S had higher PTH than those without Met S, (p<0.0001), whilst 25(OH)D levels were not significantly different (p = 0.50). In multivariate analysis, 25(OH)D was not associated with any components of the Met S however PTH was shown to be positively associated with systolic (p = 0.018) and diastolic (p = 0.005) blood pressures and waist circumference (p<0.0001) and negatively associated with HOMA (p = 0.0008) levels. Logistic regression analysis showed that Asian Indian ethnicity (OR 2.24; 95% CIs 1.57, 3.18; p<0.0001) and raised PTH (OR 2.48; 95% CIs 1.01, 6.08; p = 0.04; adjusted for 25(OH)D) produced an increased risk of Met S but 25(OH)D did not (OR 1.25; 95% CI 0.67, 2.24; p = 0.48). CONCLUSIONS: Plasma PTH but not 25(OH)D is an independent predictor of the Met S in African and Asian Indians in South Africa.

Circulating fibrocytes prepare the lung for cancer metastasis by recruiting Ly-6C+ monocytes via CCL2.

Fibrocytes are circulating, hematopoietic cells that express CD45 and Col1a1. They contribute to wound healing and several fibrosing disorders by mechanisms that are poorly understood. In this report, we demonstrate that fibrocytes predispose the lung to B16-F10 metastasis by recruiting Ly-6C(+) monocytes. To do so, we isolated fibrocytes expressing CD45, CD11b, CD13, and Col1a1 from the lungs of wild type (WT) and Ccr5(-/-) mice. WT but not Ccr5(-/-) fibrocytes increased the number of metastatic foci when injected into Ccr5(-/-) mice (73 ± 2 versus 32 ± 5; p < 0.001). This process was MMP9 dependent. Injection of WT enhanced GFP(+) fibrocytes also increased the number of Gr-1(Int), CD11b(+), and enhanced GFP(-) monocytes. Like premetastatic-niche monocytes, these recruited cells expressed Ly-6C, CD117, and CD45. The transfer of these cells into Ccr5(-/-) mice enhanced metastasis (90 ± 8 foci) compared with B cells (27 ± 2), immature dendritic cells (31 ± 6), or alveolar macrophages (28 ± 3; p < 0.05). WT and Ccl2(-/-) fibrocytes also stimulated Ccl2 expression in the lung by 2.07 ± 0.05- and 2.78 ± 0.36-fold compared with Ccr5(-/-) fibrocytes (1.0 ± 0.06; p < 0.05). Furthermore, WT fibrocytes did not increase Ly-6C(+) monocytes in Ccr2(-/-) mice and did not promote metastasis in either Ccr2(-/-) or Ccl2(-/-) mice. These data support our hypothesis that fibrocytes contribute to premetastatic conditioning by recruiting Ly-6C(+) monocytes in a chemokine-dependent process. This work links metastatic risk to conditions that mobilize fibrocytes, such as inflammation and wound repair.

Neutropenia-associated outcomes in adults with acute myeloid leukemia receiving cytarabine consolidation chemotherapy with or without granulocyte colony-stimulating factor.

STUDY OBJECTIVE: To determine whether granulocyte colony-stimulating factor (G-CSF) prophylaxis after consolidation with high- or intermediate-dose cytarabine (H/IDAC) for treatment of acute myeloid leukemia (AML) reduces the frequency of neutropenia-associated complications. DESIGN: Retrospective medical record review. SETTING: Academic medical center. PATIENTS: Seventy-eight patients aged 18 years or older in whom H/IDAC consolidation chemotherapy was initiated for consolidation of AML between November 2004 and November 2010. MEASUREMENTS AND MAIN RESULTS: Patient demographic data, information on the hospitalization for consolidation, data on G-CSF use after H/IDAC chemotherapy, and details on any readmissions were collected. Patients were deemed to have received G-CSF prophylaxis if there was documentation of the intent for use of either filgrastim or pegfilgrastim. Outcome data also were collected, including dates of relapse or second induction treatment course, and death or last follow-up visit. We compared data based on patient receipt of G-CSF (G-CSF vs no G-CSF) after each chemotherapy cycle. We assessed differences in the duration of hospitalization, fever, intravenous antibiotic use, and neutropenia, as well as rate of documented infections, time to disease recurrence, and overall survival. Compared with no G-CSF, use of G-CSF after cycle 1 of H/IDAC significantly reduced the rate of hospitalization for febrile neutropenia (p=0.039); however, no significant differences were noted for subsequent cycles. No significant differences were seen in duration of hospitalization, rate of documented infections, or time to treatment failure between groups. Overall survival was longer for patients who received G-CSF during their first cycle (p=0.018) and for those who received G-CSF during any of their cycles (p=0.04). CONCLUSION: Use of G-CSF prophylaxis after cycle 1 of H/IDAC consolidation for AML appears to reduce the frequency of hospitalization for febrile neutropenia and to increase overall survival compared with no G-CSF use. Prospective, controlled studies are needed to support our findings.

A phase I dose-escalation study of clofarabine in combination with fractionated gemtuzumab ozogamicin in patients with refractory or relapsed acute myeloid leukemia.

Clofarabine and gemtuzumab ozogamicin (GO) are active agents against acute myeloid leukemia (AML), but have not previously been tested in combination. We conducted a phase I study to determine the maximum tolerated dose (MTD) and dose limiting toxicities (DLTs) of clofarabine when combined with GO in adult patients with relapsed or refractory AML. Twenty patients received clofarabine (10, 20 or 30 mg/m(2)) on days 1-5, with GO 3 mg/m(2)/day on days 1, 4 and 7. Common dose-limiting toxicities were prolonged myelosuppression and hepatotoxicity. Clofarabine 20 mg/m(2) was the MTD, but with a DLT rate of 0.38 (5/13) - a rate that is prohibitively high to recommend for phase II study. The overall response rate (complete response [CR] + complete response with incomplete hematologic recovery [CRi]) was 42% among all patients. Thus, this combination demonstrated activity in relapsed and refractory patients, but further testing of the combination using lower doses of GO may identify more favorable rates of toxicity while maintaining efficacy.

The inflammasome component NLRP3 impairs antitumor vaccine by enhancing the accumulation of tumor-associated myeloid-derived suppressor cells.

The inflammasome is a proteolysis complex that generates the active forms of the proinflammatory cytokines interleukin (IL)-1ß and IL-18. Inflammasome activation is mediated by NLR proteins that respond to microbial and nonmicrobial stimuli. Among NLRs, NLRP3 senses the widest array of stimuli and enhances adaptive immunity. However, its role in antitumor immunity is unknown. Therefore, we evaluated the function of the NLRP3 inflammasome in the immune response using dendritic cell vaccination against the poorly immunogenic melanoma cell line B16-F10. Vaccination of Nlrp3(-/-) mice led to a relative 4-fold improvement in survival relative to control animals. Immunity depended on CD8(+) T cells and exhibited immune specificity and memory. Increased vaccine efficacy in Nlrp3(-/-) hosts did not reflect differences in dendritic cells but rather differences in myeloid-derived suppressor cells (MDSC). Although Nlrp3 was expressed in MDSCs, the absence of Nlrp3 did not alter either their functional capacity to inhibit T cells or their presence in peripheral lymphoid tissues. Instead, the absence of Nlrp3 caused a 5-fold reduction in the number of tumor-associated MDSCs found in host mice. Adoptive transfer experiments also showed that Nlrp3(-/-) MDSCs were less efficient in reaching the tumor site. Depleting MDSCs with an anti-Gr-1 antibody increased the survival of tumor-bearing wild-type mice but not Nlrp3(-/-) mice. We concluded that Nlrp3 was critical for accumulation of MDSCs in tumors and for inhibition of antitumor T-cell immunity after dendritic cell vaccination. Our findings establish an unexpected role for Nlrp3 in impeding antitumor immune responses, suggesting novel approaches to improve the response to antitumor vaccines by limiting Nlrp3 signaling.