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Lenalidomide is an immunomodulatory agent that has demonstrated clinical benefit for patients with relapsed or refractory mantle cell lymphoma ( MCL); however, despite this observed clinical activity, the mechanism of action ( MOA) of lenalidomide has not been characterized in this setting. We investigated the MOA of lenalidomide in clinical samples from patients enrolled in the CC-5013- MCL-002 trial ( NCT00875667) comparing single-agent lenalidomide versus investigator's choice single-agent therapy and validated our findings in pre-clinical models of MCL. Our results revealed a significant increase in natural killer ( NK) cells relative to total lymphocytes in lenalidomide responders compared to non-responders that was associated with a trend towards prolonged progression-free survival and overall survival. Clinical response to lenalidomide was independent of baseline tumour microenvironment expression of its molecular target, cereblon, as well as genetic mutations reported to impact clinical response to the Bruton tyrosine kinase inhibitor ibrutinib. Preclinical experiments revealed lenalidomide enhanced NK cell-mediated cytotoxicity against MCL cells via increased lytic immunological synapse formation and secretion of granzyme B. In contrast, lenalidomide exhibited minimal direct cytotoxic effects against MCL cells. Taken together, these data provide the first insight into the clinical activity of lenalidomide against MCL, revealing a predominately immune-mediated MOA. [ABSTRACT FROM AUTHOR]

publisher‐imprint‐name Springer volume‐issue‐count 1 issue‐article‐count 0 issue‐toc‐levels 0 issue‐pricelist‐year 2016 issue‐copyright‐holder The Author(s) issue‐copyright‐year 2016 article‐contains‐esm Yes article‐numbering‐style Unnumbered article‐registration‐date‐year 2016 article‐registration‐date‐month 8 article‐registration‐date‐day 10 article‐toc‐levels 0 toc‐levels 0 volume‐type Regular journal‐product ArchiveJournal numbering‐style Unnumbered article‐grants‐type OpenChoice metadata‐grant OpenAccess abstract‐grant OpenAccess bodypdf‐grant OpenAccess bodyhtml‐grant OpenAccess bibliography‐grant OpenAccess esm‐grant OpenAccess online‐first false pdf‐file‐reference BodyRef/PDF/40169_2016_Article_117.pdf pdf‐type Typeset target‐type OnlinePDF issue‐type Regular article‐type OriginalPaper journal‐subject‐primary Medicine & Public Health journal‐subject‐secondary Medicine/Public Health, general journal‐subject‐collection Medicine open‐access true --> Background: Lung remodeling and pulmonary fibrosis are serious, life‐threatening conditions resulting from diseases such as chronic severe asthma and idiopathic pulmonary fibrosis (IPF). Preclinical evidence suggests that JNK enzyme function is required for key steps in the pulmonary fibrotic process. However, a selective JNK inhibitor has not been investigated in translational models of lung fibrosis with clinically relevant biomarkers, or in IPF patients. Methods: The JNK inhibitor CC‐930 was evaluated in the house dust mite‐induced fibrotic airway mouse model, in a phase I healthy volunteer pharmacodynamic study, and subsequently in a phase II multicenter study of mild/moderate IPF (n = 28), with a 4‐week, placebo‐controlled, double‐blind, sequential ascending‐dose period (50 mg QD, 100 mg QD, 100 mg BID) and a 52‐week open‐label treatment‐extension period. Results: In the preclinical model, CC‐930 attenuated collagen 1A1 gene expression, peribronchiolar collagen deposition, airway mucin MUC5B expression in club cells, and MMP‐7 expression in lung, bronchoalveolar lavage fluid, and serum. In the phase I study, CC‐930 reduced c‐Jun phosphorylation induced by UV radiation in skin. In the phase II IPF study, there was a CC‐930 dose‐dependent trend in reduction of MMP‐7 and SP‐D plasma protein levels. The most commonly reported adverse events were increased ALT, increased AST, and upper respiratory tract infection (six subjects each, 21.4 %). A total of 13 subjects (46.4 %) experienced adverse events that led to discontinuation of study drug. Nine out of 28 subjects experienced progressive disease in this study. The mean FVC (% predicted) declined after 26–32 weeks at doses of 100 mg QD and 100 mg BID. Changes in MMP‐7, SP‐D, and tenascin‐C significantly correlated with change in FVC (% predicted). Conclusions: These results illustrate JNK enzymatic activity involvement during pulmonary fibrosis, and support systemic biomarker use for tracking disease progression and the potential clinical benefit of this novel intervention in IPF. Trial registration ClinicalTrials.gov NCT01203943 [ABSTRACT FROM AUTHOR]

Pomalidomide is an IMiD® immunomodulatory agent, which has shown clinically significant benefits in relapsed and/or refractory multiple myeloma (rr MM) patients when combined with dexamethasone, regardless of refractory status to lenalidomide or bortezomib. (Schey et al, ; San Miguel et al, 2013; Richardson et al, 2014; Scott, ) In this work, we present preclinical data showing that the combination of pomalidomide with dexamethasone (PomDex) demonstrates potent anti-proliferative and pro-apoptotic activity in both lenalidomide-sensitive and lenalidomide-resistant MM cell lines. PomDex also synergistically inhibited tumour growth compared with single-agent treatment in xenografts of lenalidomide-resistant H929 R10-1 cells. Typical hallmarks of IMiD compound activity, including IKZF3 (Aiolos) degradation, and the downregulation of interferon regulatory factor (IRF) 4 and MYC, seen in lenalidomide-sensitive H929 MM cell lines, were also observed in PomDex-treated lenalidomide-resistant H929 MM cells. Remarkably, this resulted in strong, synergistic effects on the induction of apoptosis in both lenalidomide-sensitive and resistant MM cells. Furthermore, gene expression profiling revealed a unique differential gene expression pattern in PomDex-treated samples, highlighted by the modulation of pro-apoptotic pathways in lenalidomide-resistant cells. These results provide key insights into molecular mechanisms of PomDex in the lenalidomide-resistant setting. [ABSTRACT FROM AUTHOR]

Background: The mammalian target of rapamycin (mTOR) pathway is essential for tumor development, yet mTOR inhibitors have yielded modest results. This phase 1 study investigated the mTORC1/mTORC2 inhibitor CC-223 in patients with advanced cancer.Methods: Patients with advanced solid tumors or multiple myeloma received an initial dose of 7.5-60 mg of CC-223, followed by oral daily dosing in 28-day cycles until disease progression. The primary objective was to determine the safety, tolerability, nontolerated dosage, maximum tolerated dosage (MTD), and preliminary pharmacokinetic profile. Secondary objectives were to evaluate pharmacodynamic effects and to describe preliminary efficacy.Results: Twenty-eight patients were enrolled and received ≥1 dose of CC-223. The most common treatment-related grade 3 adverse events were hyperglycemia, fatigue, and rash. Four patients had dose-limiting toxicities, including hyperglycemia, rash, fatigue, and mucositis. Therefore, 45 mg/d was determined to be the MTD. The pharmacokinetics of CC-223 demonstrated a mean terminal half-life ranging from 4.86 to 5.64 hours and maximum observed plasma concentration ranging from 269 to 480 ng/mL in patients who received CC-223 ≥45 mg/d. Phosphorylation of mTORC1/mTORC2 pathway biomarkers in blood cells was inhibited by CC-223 ≥30 mg/d with an exposure-response relationship. Best responses included 1 partial response (breast cancer; response duration 220 days; 30-mg/d cohort), stable disease (8 patients across ≥15 mg/d cohorts; response duration range, 36-168 days), and progressive disease (12 patients). The disease control rate was 32%.Conclusions: CC-223 was tolerable, with manageable toxicities. Preliminary antitumor activity, including tumor regression, and evidence of mTORC1/mTORC2 pathway inhibition were observed. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize population pharmacokinetics and the exposure-neutropenia relationship with nanoparticle albumin-bound (nab)-paclitaxel in patients with solid tumors. Plasma and blood concentrations of paclitaxel and neutrophil data were collected from 150 patients with various solid tumors over the nab-paclitaxel dose range of 80-375 mg/m². Data were analyzed using nonlinear mixed-effect modeling or logistic regression. Pharmacokinetics of nab-paclitaxel were described by a 3-compartment model with saturable distribution and elimination. The rapid disappearance of circulating paclitaxel was driven by its fast distribution to peripheral compartments; maximum rate for saturable distribution (325000 μg/h) was 40-fold greater than that for saturable elimination (8070 μg/h). Albumin was a significant covariate of paclitaxel elimination (P<.001), while total bilirubin, creatinine clearance, body size, age, sex, and tumor type had no significant or clinically relevant effect. The probability of experiencing a ≥ 50% reduction in neutrophils was best correlated to the duration above the drug concentration of 720 ng/mL. At a given exposure level, neutropenia development was positively correlated with increasing age but not significantly influenced by hepatic function, tumor type, sex, or dosing schedule. Covariate analyses supports exposure-matched dose adjustments in patients with moderate to severe hepatic impairment. [ABSTRACT FROM AUTHOR]

Sotatercept ( ACE-011), a recombinant human fusion protein containing the extracellular domain of the human Activin receptor IIA, binds to and inhibits activin and other members of the transforming growth factor -β ( TGF-β) superfamily. Administration of sotatercept led to a rapid and sustained increase in red blood cell ( RBC) count and haemoglobin (Hb) in healthy volunteers (phase I clinical trials), but the mechanism is not fully understood. Mice treated with RAP-011 (murine ortholog of ACE-011) respond with a rapid (within 24 h) increase in haematocrit, Hb, and RBC count. These effects are accompanied by an equally rapid stimulation of late-stage erythroid precursors in the bone marrow ( BM). RAP-011 also induces a significant increase in erythroid burst-forming units and erythropoietin, which could contribute to additional, sustained effects on RBC production. Further in vitro co-culture studies demonstrate that BM accessory cells are required for RAP-011 effects. To better understand which TGF-β family ligand(s) mediate RAP-011 effects, we evaluated the impact of several of these ligands on erythroid differentiation. Our data suggest that RAP-011 may act to rescue growth differentiation factor 11/Activin A-induced inhibition of late-stage erythropoiesis. These data define the mechanism of action of a novel agent that regulates RBC differentiation and provide the rationale to develop sotatercept for the treatment of anaemia and ineffective erythropoiesis. [ABSTRACT FROM AUTHOR]

Cereblon ( CRBN), the molecular target of lenalidomide and pomalidomide, is a substrate receptor of the cullin ring E3 ubiquitin ligase complex, CRL4 CRBN. T cell co-stimulation by lenalidomide or pomalidomide is cereblon dependent: however, the CRL4 CRBN substrates responsible for T cell co-stimulation have yet to be identified. Here we demonstrate that interaction of the transcription factors Ikaros ( IKZF1, encoded by the IKZF1 gene) and Aiolos ( IKZF3, encoded by the IKZF3 gene) with CRL4 CRBN is induced by lenalidomide or pomalidomide. Each agent promotes Aiolos and Ikaros binding to CRL4 CRBN with enhanced ubiquitination leading to cereblon-dependent proteosomal degradation in T lymphocytes. We confirm that Aiolos and Ikaros are transcriptional repressors of interleukin-2 expression. The findings link lenalidomide- or pomalidomide-induced degradation of these transcriptional suppressors to well documented T cell activation. Importantly, Aiolos could serve as a proximal pharmacodynamic marker for lenalidomide and pomalidomide, as healthy human subjects administered lenalidomide demonstrated Aiolos degradation in their peripheral T cells. In conclusion, we present a molecular model in which drug binding to cereblon results in the interaction of Ikaros and Aiolos to CRL4 CRBN, leading to their ubiquitination, subsequent proteasomal degradation and T cell activation. [ABSTRACT FROM AUTHOR]

Cereblon, a member of the cullin 4 ring ligase complex ( CRL4), is the molecular target of the immunomodulatory drugs ( IMi Ds) lenalidomide and pomalidomide and is required for the antiproliferative activity of these agents in multiple myeloma ( MM) and immunomodulatory activity in T cells. Cereblon's central role as a target of lenalidomide and pomalidomide suggests potential utility as a predictive biomarker of response or resistance to IMi D therapy. Our studies characterized a cereblon monoclonal antibody CRBN65, with high sensitivity and specificity in Western analysis and immunohistochemistry that is superior to commercially available antibodies. We identified multiple cereblon splice variants in both MM cell lines and primary cells, highlighting challenges with conventional gene expression assays given this gene complexity. Using CRBN65 antibody and Taq Man quantitative reverse transcription polymerase chain reaction assays, we showed lack of correlation between cereblon protein and mRNA levels. Furthermore, lack of correlation between cereblon expression in MM cell lines and sensitivity to lenalidomide was shown. In cell lines made resistant to lenalidomide and pomalidomide, cereblon protein is greatly reduced. These studies show limitations to the current approaches of cereblon measurement that rely on commercial reagents and assays. Standardized reagents and validated assays are needed to accurately assess the role of cereblon as a predictive biomarker. [ABSTRACT FROM AUTHOR]

Durable responses with lenalidomide monotherapy have been reported in patients with non-Hodgkin lymphoma. In relapsed/refractory diffuse large B-cell lymphoma ( DLBCL), higher responses were observed in the activated B-cell-like ( ABC) subtype than in the germinal centre B-cell-like subtype. Herein, the molecular mechanisms involved in the differential efficacy of lenalidomide in DLBCL subtypes were investigated. Using DLBCL cell lines, lenalidomide treatment was found to preferentially suppress proliferation of ABC- DLBCL cells in vitro and delay tumour growth in a human tumour xenograft model, with minimal effect on non- ABC- DLBCL cells. This tumouricidal effect was associated with downregulation of interferon regulatory factor 4 ( IRF4), a hallmark of ABC- DLBCL cells. IRF4 inhibition by lenalidomide induced downregulation of B-cell receptor ( BCR)-dependent NF-κB. Whereas IRF4-specific small, interfering RNA mimicked the effects of lenalidomide reducing NF-κB activation, IRF4 overexpression enhanced NF-κB activation and conferred resistance to lenalidomide. These findings indicate the crucial role of IRF4 inhibition in lenalidomide efficacy in ABC cells. Furthermore, lenalidomide-induced IRF4 downregulation required the expression of cereblon, a molecular target of lenalidomide. Taken together, these findings suggest that lenalidomide has direct antitumour activity against DLBCL cells, preferentially ABC- DLBCL cells, by blocking IRF4 expression and the BCR- NF-κB signalling pathway in a cereblon-dependent manner. [ABSTRACT FROM AUTHOR]

Summary [ABSTRACT FROM AUTHOR]

Lenalidomide (REVLIMID™), an immunomodulatory compound targeting both cancer cells and their microenvironment, has substantial activity in several difficult-to-manage hematological malignancies. In previously treated multiple myeloma, lenalidomide produces high-quality responses combined with sustained disease control. Recently, several randomized studies have demonstrated a clinical benefit of continuous lenalidomide treatment in newly diagnosed multiple myeloma. In many patients with refractory anemia associated with lower risk myelodysplastic syndromes and a 5q chromosome deletion, lenalidomide leads to transfusion independence, considerably improving quality of life. It has a manageable safety profile, and its oral formulation reduces the burden on patients. Several phase III trials are ongoing in other indications currently underserved by conventional therapy, such as chronic lymphocytic leukemia, non-Hodgkin's lymphoma, and prostate cancer. Several early-stage studies are exploring lenalidomide alone and in combination across different hematological malignancies, solid tumors, and immune-related disorders. [ABSTRACT FROM AUTHOR]

Summary. A number of alternatively spliced isoforms of haemopoietic growth factor receptors (HGFRs) have been described, but their role in human haemopoiesis remains undetermined. We have investigated the relative expression of the α1 and α2 isoforms of human granulocyte/macrophage colony-stimulating factor receptor (hGM-CSFR) during haemopoietic cell differentiation, and have shown that both subunits are independently regulated during differentiation of CD34+ human haemopoietic progenitor cells. To further investigate these ex-vivo observations, we established a series of murine FDCP mix cell lines, which, as a consequence of the ectopic expression of α1 or α2 hGM-CSFR, demonstrated differential differentiation responses to hGM-CSF. In this model system, hGM-CSFR-α2-expressing cells showed increased hGM-CSF-mediated erythroid/megakaryocytic differentiation compared with hGM-CSFR-α1-expressing cells. [ABSTRACT FROM AUTHOR]

Summary. Indications for platelet transfusion remain controversial and are frequently based on arbitrary numerical criteria. In October 2000, we introduced a stringent prophylactic-platelet transfusion policy < 10 × 109 /l for stable patients and < 20 × 109 /l in the presence of major bleeding or additional risk factors. A trigger of < 50 × 109 /l was introduced for patients undergoing invasive procedures. A prospective analysis was performed measuring the frequency of minor and major bleeding events, morbidity, mortality and duration of pancytopenia. Blood product usage was assessed and health care savings measured. A total of 98 patients were evaluated on 2147 patient study days and 271 bleeding episodes were recorded. Major bleeding occurred on 1·39% (30/2147) of the study days when platelet counts were < 10 × 109 /l and 2·3% (50/2147) of the study days when platelet counts were 10–20 × 109 /l. In patients with platelets > 20 × 109 /l, there were 117 major bleeding episodes observed on 5·4% of the study days. In patients with no identified additional risk factors present, major haemorrhages were recorded in 0·51% (11/2147) of the study days in patients with platelet counts ≥ 10 × 109 /l. There was a 36% reduction in platelet units transfused compared with retrospective data when an arbitrary transfusion trigger of 20 × 109 /l was in place (P = < 0·02). Of note, a 16% reduction in red cell transfusions was recorded. These data confirm that the introduction of a transfusion trigger of < 10 × 109 /l in the absence of fresh bleeding and sepsis (> 38°C) is safe and has a significant impact on overall hospital transfusion costs. [ABSTRACT FROM AUTHOR]

Human haemopoiesis undergoes profound changes throughout life, resulting in compromised regenerative capacity of haemopoietic stem cells. It has been suggested that telomere shortening results in senescence of haemopoietic stem cell subsets and may influence the balance between stem cell renewal and proliferation. Telomere length and telomerase activity was measured in whole blood leucocytes, neutrophils and T cells from cord blood and individuals aged from 1 year to 96 years. Rapid telomere shortening [700 base pairs (bp)] was demonstrated in the first year of life, followed by a gradual decline of 31 bp/year. T cells were shown to have longer telomeres than neutrophils (mean difference 372 bp, P = < 0·001) but demonstrated similar rates of shortening (20 ± 0·3 bp/year vs. 22 ± 0·3 bp/year). Telomerase was detectable in T cells but not in neutrophils, suggesting that telomerase is not the rate-limiting step for regulation of telomere length in haemopoietic cells. Stem cell utilization as measured by X chromosome inactivation patterns was found to be independent of telomere length. This supports the concept that age-dependent skewed haemopoiesis is the result of random stem cell loss or X-allelic exclusion rather than telomeric senescence. These studies provide insight into the ageing process and a reference point for evaluating replicative stress in individuals of different age groups. [ABSTRACT FROM AUTHOR]

Cereblon ( CRBN), the molecular target of lenalidomide and pomalidomide, is a substrate receptor of the cullin ring E3 ubiquitin ligase complex, CRL4 CRBN. T cell co-stimulation by lenalidomide or pomalidomide is cereblon dependent: however, the CRL4 CRBN substrates responsible for T cell co-stimulation have yet to be identified. Here we demonstrate that interaction of the transcription factors Ikaros ( IKZF1, encoded by the IKZF1 gene) and Aiolos ( IKZF3, encoded by the IKZF3 gene) with CRL4 CRBN is induced by lenalidomide or pomalidomide. Each agent promotes Aiolos and Ikaros binding to CRL4 CRBN with enhanced ubiquitination leading to cereblon-dependent proteosomal degradation in T lymphocytes. We confirm that Aiolos and Ikaros are transcriptional repressors of interleukin-2 expression. The findings link lenalidomide- or pomalidomide-induced degradation of these transcriptional suppressors to well documented T cell activation. Importantly, Aiolos could serve as a proximal pharmacodynamic marker for lenalidomide and pomalidomide, as healthy human subjects administered lenalidomide demonstrated Aiolos degradation in their peripheral T cells. In conclusion, we present a molecular model in which drug binding to cereblon results in the interaction of Ikaros and Aiolos to CRL4 CRBN, leading to their ubiquitination, subsequent proteasomal degradation and T cell activation. [ABSTRACT FROM AUTHOR]

Cereblon (CRBN), the molecular target of lenalidomide and pomalidomide, is a substrate receptor of the cullin ring E3 ubiquitin ligase complex, CRL4(CRBN) . T cell co-stimulation by lenalidomide or pomalidomide is cereblon dependent: however, the CRL4(CRBN) substrates responsible for T cell co-stimulation have yet to be identified. Here we demonstrate that interaction of the transcription factors Ikaros (IKZF1, encoded by the IKZF1 gene) and Aiolos (IKZF3, encoded by the IKZF3 gene) with CRL4(CRBN) is induced by lenalidomide or pomalidomide. Each agent promotes Aiolos and Ikaros binding to CRL4(CRBN) with enhanced ubiquitination leading to cereblon-dependent proteosomal degradation in T lymphocytes. We confirm that Aiolos and Ikaros are transcriptional repressors of interleukin-2 expression. The findings link lenalidomide- or pomalidomide-induced degradation of these transcriptional suppressors to well documented T cell activation. Importantly, Aiolos could serve as a proximal pharmacodynamic marker for lenalidomide and pomalidomide, as healthy human subjects administered lenalidomide demonstrated Aiolos degradation in their peripheral T cells. In conclusion, we present a molecular model in which drug binding to cereblon results in the interaction of Ikaros and Aiolos to CRL4(CRBN) , leading to their ubiquitination, subsequent proteasomal degradation and T cell activation., (© 2013 The Authors. British Journal of Haematology published by John Wiley & Sons Ltd.)

A number of alternatively spliced isoforms of haemopoietic growth factor receptors (HGFRs) have been described, but their role in human haemopoiesis remains undetermined. We have investigated the relative expression of the alpha1 and alpha2 isoforms of human granulocyte/macrophage colony-stimulating factor receptor (hGM-CSFR) during haemopoietic cell differentiation, and have shown that both subunits are independently regulated during differentiation of CD34+ human haemopoietic progenitor cells. To further investigate these ex-vivo observations, we established a series of murine FDCP mix cell lines, which, as a consequence of the ectopic expression of alpha1 or alpha2 hGM-CSFR, demonstrated differential differentiation responses to hGM-CSF. In this model system, hGM-CSFR-alpha2-expressing cells showed increased hGM-CSF-mediated erythroid/megakaryocytic differentiation compared with hGM-CSFR-alpha1-expressing cells.