ALBERT

Description: Microbial survival strategies in ancient permafrost: insights from metagenomics The ISME Journal 11, 2305 (October 2017). doi:10.1038/ismej.2017.93 Authors: Rachel Mackelprang, Alexander Burkert, Monica Haw, Tara Mahendrarajah, Christopher H Conaway, Thomas A Douglas & Mark P Waldrop

Description: An article published in the International Journal of Environmental Research and Public Health compares two types of specific absorption rate measurement systems—a fast system using a time-domain array and a traditional system using probe scanning. While the time-domain array system is analyzed in detail under idealized conditions, the probe-scanning system evaluation used a fixed set of scanning and evaluation parameters that are not fully compliant with the requirements of the published standards. This leads to a false comparison and the incorrect conclusion that time-domain array systems can be theoretically more accurate than probe-scanning systems. We have repeated the analysis applied in the paper using the same raw data but with state-of-the art scanning and evaluation parameters. The results confirm the high accuracy of probe-scanning systems for any field distribution. Due to the high precision, robustness, and reliability of probe-scanning systems, the results of these systems are often referred to as reference results.

Description: Phosphoinositide-3 kinases (PI3Ks) are key cellular signaling proteins that act as a central node, relaying signals from cell surface receptors to downstream mediators such as AKT. The PI3K-δ and PI3K-γ isoforms are preferentially expressed in normal and malignant leukocytes where they play critical roles in cell differentiation, migration, and proliferation. IPI-145 is a potent, oral PI3K-δ,γ inhibitor that has shown clinical activity in the Phase 1 trial (IPI-145-02) in patients with advanced hematologic malignancies (ClinicalTrials.gov NCT01476657). Cytokines, chemokines, and matrix metalloproteinases (MMPs) play key roles in the homing, migration and activation of normal immune cells, and can have similar effects on malignant leukocytes. To further explore the biological effects of IPI-145, a panel of cytokines, chemokines, and MMPs were evaluated at several time points in the serum of patients enrolled in the IPI-145-02 trial. Serum was collected from consenting subjects at baseline, Cycle 1 Day 8 (C1D8), and Cycle 2 Day 1 (C2D1). Serum was frozen and stored at -80°C prior to analysis. Serum proteins were analyzed using Luminex xMAP(®) technology in which analytes are captured on uniquely labeled fluorescent beads, and the amount of analyte is quantified using an LED CCD camera contained in Millipore's MagPix(®) instrument. Multiplex panels of cytokines, chemokines and MMPs covering 72 analytes were evaluated in 30 chronic lymphocytic leukemia (CLL) and 19 indolent non-Hodgkin lymphoma (iNHL) subjects. Each sample was tested in duplicate, and duplicate measurements were averaged. Measurements were excluded from further analysis if duplicate readings exhibited a coefficient of variation of greater than 20% or if all values for a specific analyte and subject were below the limit of detection. Each analyte was evaluated for evidence of a consistent change (reduction or increase) in serum levels at C1D8 and/or C2D1 compared to baseline. When data were compared between CLL subjects treated with IPI-145 at 25 mg twice daily (BID) and those treated at 75 mg BID, no clear differences in serum analyte levels were observed, although the population subgroups were relatively small. For the purposes of this analysis, all doses were pooled together (n=1 at 8 mg BID, 2 at 15 mg BID, 15 at 25 mg BID, and 13 at 75 mg BID). Likewise, the iNHL dose groups were also pooled (n=1 at 15 mg BID, 12 at 25 mg BID, 1 at 50 mg BID, and 5 at 75 mg BID). In CLL subjects, 9 of 72 analytes decreased after IPI-145 treatment compared to baseline, whereas none increased significantly. Analytes that decreased after IPI-145 treatment include CXCL13, CCL3, CCL4, IL-10, TNFα, IL-12p40, MMP-9, CCL17 and CCL22. Median serum levels of these analytes decreased by C1D8, ranging from 16% to 59% of baseline. In iNHL subjects, median serum levels of 7 analytes decreased by C1D8 (ranging from 32% to 70% of baseline), whereas none increased significantly. Of the 7 analytes that decreased in iNHL subjects, 5 also decreased in CLL subjects (CXCL13, MMP-9, TNFα, CCL17 and CCL22) and 2 were distinct (CCL1 and MMP-12). Interestingly, many of the analytes that decreased with IPI-145 treatment are involved in the communication between malignant B-cells and the microenvironment. CCL3, CCL4, CCL17 and CCL22 are expressed by malignant B-cells and may play a role in recruiting T-cells to interact with the malignant B-cells. CXCL13 is secreted by stromal cells and recruits malignant B-cells to the lymph nodes. In addition, IL-10 is produced by many normal immune cell types as well as by neoplastic B-cells. IL-10 is known to be an autocrine growth factor for B-cell lymphoma cell lines. These pharmacodynamic data provide further evidence for biological activity of IPI-145 in patients with CLL and iNHL and suggest both similarities and differences in how these two malignancies respond to IPI-145. The association of many of these pharmacodynamic factors with the tumor microenvironment suggests a mechanistic basis for the clinical observation of lymphocytosis and nodal reduction with IPI-145 treatment of CLL subjects. Cytokine, chemokine and MMP levels from patients in IPI-145-02 are being evaluated further for associations with multiple clinical parameters to determine if there is evidence for biomarkers predictive of efficacy and tolerability. Disclosures: Douglas: Infinity Pharmaceuticals, Inc.: Employment. Allison:Infinity Pharmaceuticals, Inc.: Employment. Ted:Infinity Pharmaceuticals, Inc.: Employment. Allen:Infinity Pharmaceuticals, Inc.: Employment. Kahl:Infinity Pharmaceuticals, Inc.: Consultancy, Research Funding. Horwitz:Celgene, Allos, Seattle Genetics, Bristol-Myers Squibb, Genzyme, Kyowa, Janssen, Johnson & Johnson, Millenium: Consultancy; Celgene, Allos, Seattle Genetics, Kyowa, Infinty, Millenium: Research Funding. Flinn:Infinity Pharmaceuticals, Inc.: Consultancy, Research Funding. Kelly:Infinity Pharmaceuticals, Inc.: Employment. Stern:Infinity Pharmaceuticals, Inc.: Employment.

Description: The pandemic of coronavirus disease 2019 (COVID-19), with rising numbers of patients worldwide, presents an urgent need for effective treatments. To date, there are no therapies or vaccines that are proven to be effective against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Several potential candidates or repurposed drugs are under investigation, including drugs that inhibit SARS-CoV-2 replication and block infection. The most promising therapy to date is remdesivir, which is US Food and Drug Administration (FDA) approved for emergency use in adults and children hospitalized with severe suspected or laboratory-confirmed COVID-19. Herein we summarize the general features of SARS-CoV-2’s molecular and immune pathogenesis and discuss available pharmacological strategies, based on our present understanding of SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV) infections. Finally, we outline clinical trials currently in progress to investigate the efficacy of potential therapies for COVID-19.

Description: Background: The neoplastic B cells of indolent non-Hodgkin lymphoma (iNHL) and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) rely upon the support of non-neoplastic cells within their microenvironment for proliferation and survival. Support cells include T cells, myeloid-derived cells, and mesenchymal stromal cells, which provide phosphoinositide-3 kinase (PI3K)-dependent survival and growth signals for the neoplastic cells, as well as signals that maintain the tumor microenvironment (TME). Duvelisib (IPI-145) is an oral inhibitor of PI3K-δ,γ in clinical development for iNHL and CLL/SLL. To better understand the roles of the PI3K-δ and PI3K-γ isoforms in mediating signaling between the tumor and TME cells in B-cell malignancies, Infinity’s highly potent (low nM) PI3K isoform-selective compounds that target either PI3K-δ or PI3K-γ with 〉100-fold selectivity over the other PI3K isoforms were utilized in in vitro experiments. Methods/Results: A mixture of cytokines (CD40L/IL-2/IL-10) was utilized in an assay that recapitulated TME-induced malignant B-cell proliferative responses. Duvelisib inhibited CD40L/IL-2/IL-10-induced proliferation of primary CLL cells with an average IC50 in the sub-nanomolar range. The use of PI3K isoform-selective inhibitory compounds revealed these proliferative signals are PI3K-δ dependent, as the PI3K-δ-selective inhibitor was more active than the PI3K-γ-selective inhibitor. While these experiments established the direct PI3K-δ dependence of TME-derived cytokines on CLL cell proliferation, the role of PI3K-γ in key functions such as the directed migration of normal immune cells of the TME was also tested. We hypothesized that chemokines that recruit immune cells to the TME would signal through G-protein coupled receptors linked to PI3K-γ. The stromally-derived chemokine CXCL12 resulted in upregulation of phospho (p)-AKT in both the CD3+ T-cell and CLL-cell populations in CLL patient total peripheral blood mononuclear cells (PBMCs). Using isoform-selective inhibitors, the increase in CXCL12-induced pAKT in CD3+ T cells was found to be mediated by PI3K-γ. Interestingly, within the malignant B-cell population, the increase in CXCL12-induced pAKT was PI3K-δ dependent, suggesting that CXCL12 signals through different PI3K isoforms in these varying cell types. Chemotactic assays demonstrated reduced migration of total CLL PBMCs towards CXCL12 in the presence of combined PI3K-δ and PI3K-γ inhibition by duvelisib. Flow cytometric analyses of the migrating populations revealed that the greatest effect of duvelisib on CXCL12-induced migration occurred primarily within the T-cell population. Utilizing PI3K isoform-selective compounds, the inhibition of T-cell migration toward CXCL12 was found to be a PI3K-γ mediated process, as the PI3K-γ-selective inhibitor was more potent than the PI3K-δ-selective inhibitor in blocking T-cell migration. Myeloid-derived cells and mesenchymal stromal cells can also support CLL cell survival as components of the TME. Recent reports suggest that CLL cytoprotective nurse-like cells may have an M2 polarization and be similar to the immunosuppressive myeloid-derived suppressor cells found in some solid tumors [Gianonni et al. Haematologica 2014, 99(6)]. To model these TME components, mouse bone marrow cells were differentiated into macrophages with murine MCSF and IL-4 (M2–polarized). CXCL12-induced pAKT in these M2 cells, which express CXCR4, was more potently inhibited by duvelisib and the PI3K-γ-selective inhibitor than the PI3K-δ-selective inhibitor. Finally, co-cultures of M2 macrophages with CLL cells led to extended CLL cell survival. These data show that CXCL12 mediated-M2 activation is dependent upon PI3K-γ and that M2-cells can act to support CLL cell survival. Conclusions: T cells and myeloid cells provide a survival and proliferative advantage to malignant CLL cells within the TME. The role of PI3K-γ in the migration and activation of these cells supports the potential for therapeutic benefit from inhibition of PI3K-γ. By inhibiting both the PI3K-δ and PI3K-γ isoforms, duvelisib is uniquely positioned to inhibit key signals important in the pathogenesis of B-cell malignancies. Disclosures Peluso: Infinity Pharmaceuticals, Inc.: Employment. Faia:Infinity Pharmaceuticals, Inc.: Employment. Winkler:Infinity Pharmaceuticals, Inc.: Employment. Patel:Infinity Pharmaceuticals, Inc.: Employment. Brophy:Infinity Pharmaceuticals, Inc.: Employment. White:Infinity Pharmaceuticals, Inc.: Employment. Douglas:Infinity Pharmaceuticals, Inc.: Employment. Stern:Infinity Pharmaceuticals, Inc.: Employment. Palombella:Infinity Pharmaceuticals, Inc.: Employment. McGovern:Infinity Pharmaceuticals, Inc.: Employment. Kutok:Infinity Pharmaceuticals, Inc.: Employment.

Description: Introduction: Peripheral T-cell lymphoma (PTCL) and cutaneous T-cell lymphoma (CTCL) are uncommon lymphoid malignancies. Approved agents in the relapsed setting have overall response rates (ORR) in the range of 25-35%. Phosphoinositide-3-Kinases (PI3K) are pivotal in cell signaling and regulate multiple cellular functions relevant to oncogenesis. PI3K-δ and PI3K-γ isoforms are preferentially expressed in leukocytes with distinct roles in T-cell function. PI3K-δ and PI3K-γ are central to the growth and survival of certain T-cell malignancies and inhibition of PI3K is a therapeutic strategy for PTCL and CTCL. Duvelisib (IPI-145), an oral inhibitor of PI3K-δ and PI3K-γ, was studied in a phase 1 trial in hematologic malignancies with disease-specific expansion cohorts at the maximum tolerated dose (MTD). Responses were seen in a substantial number of patients with relapsed or refractory PTCL and CTCL. Methods: This study evaluated the safety, maximum tolerated dose (MTD), pharmacokinetics, pharmacodynamics, and clinical activity of duvelisib administered twice daily (BID), continuously in 28-day cycles. Patients with relapsed or refractory leukemia or lymphoma received doses ranging from 8 mg to 100 mg BID. A disease-specific cohort at the MTD included PTCL and CTCL patients. The pharmacodynamics of duvelisib were assessed by early positron-emission tomography (PET) in a subset of patients and in serum through evaluation of a panel of cytokines, chemokines, and matrix metalloproteinase. Results: Thirty-three patients with TCL (17 CTCL, 16 PTCL) received duvelisib primarily at the MTD of 75 mg BID (25 mg, n=1; 50 mg, n=1; 60 mg, n=4; 75 mg, n=25; 100 mg, n=2). The median age was 64 years (range: 34-86), and the median number of prior therapies was 4 (range: 1-11). The median time from last prior therapy to first dose of duvelisib was 1.05 months (range: 0.2-36). Thirty-one patients were evaluable for efficacy, with an ORR of 42% (13/31). The ORR in PTCL was 47% (7/15, 2 complete responses [CR], 5 partial responses [PR]) and in CTCL 38% (6/16, 6 PR). The median time to response was 1.9 months (range: 1.5-3.8). Median overall survival (OS) was 36.4 weeks (95% CI: 18.6, –) for patients with PTCL. The median OS was not yet reached for patients with CTCL. The median number of treatment cycles was 3.1 (range: 0.5-12.5), with 14 (42%) on treatment ≥4 cycles (16 weeks). Pharmacodynamic results showed that within 8 days of starting treatment with duvelisib, modulation of serum cytokines and chemokines known to play a role in leukocyte migration and support the tumor microenvironment was observed. Furthermore, a reduction in standard uptake value (SUV) from baseline was observed in 6/11 patients evaluated by PET at Cycle 1 Day 22. (All 6 patients with reduction in SUV received duvelisib ≥60 mg BID). Twenty-six (79%) patients had adverse events (AEs) ≥Grade 3, with the most common (≥10%) being increased ALT/AST (n=12, 36%), rash (combined terms) (n=7, 21%), and neutropenia (n=5, 15%). Ten (30%) patients discontinued treatment due to an AE, with the most common (〉1 patient) being increased ALT/AST [n=5 (4 CTCL, 1 PTCL), 15%]. Three TCL patients died on treatment or within 30 days of the last dose of duvelisib, one due to disease progression, one who declined supportive therapy, and one due to HSV pneumonia (patient was not receiving HSV prophylaxis). Conclusions: Duvelisib has shown clinical activity in patients with relapsed/refractory TCL (ORR 42%, including 2 CR) with an acceptable safety profile that supports continued assessment in this heavily pretreated patient population. The preliminary results support further evaluation of duvelisib in patients with TCL, including additional studies in both CTCL and PTCL to determine the optimal dose and identify appropriate combination therapy. Disclosures Horwitz: Research: Celgene, Millennium, Infinity, Kiowa-Kirin, Seattle Genetics, SpectrumConsulting: Amgen, Bristol-Myers Squibb, Celgene, Jannsen, Millennium, seattle genetics: Consultancy, Honoraria, Research Funding. Off Label Use: ipi-145 is not an approved drug. Porcu:Actelion (e), Cutaneous Lymphoma Foundation (h), United States Cutaneous Lymphoma Consortium (h), Infinity (d), Celgene (d), : Consultancy, Employment, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Flinn:Infinity Pharmaceuticals: Consultancy. Kahl:Infinity Pharmaceuticals: Consultancy, Research Funding. Sweeney:Infinity Pharmaceuticals: Employment. Stern:Infinity Pharmaceuticals, Inc.: Employment. Douglas:Infinity Pharmaceuticals, Inc.: Employment. Allen:Infinity Pharmaceuticals: Employment. Kelly:Infinity Pharmaceuticals: Employment. Foss:Eisai, Celgene, Seattle Genetics: Consultancy, Research Funding, Speakers Bureau.

Description: Key Points The oral PI3K-δ,γ inhibitor duvelisib demonstrated clinical activity and a favorable safety profile in patients with CTCL and PTCL. Duvelisib induced cell-autonomous killing of TCL lines and reprogrammed PTCL-associated macrophages in vivo.