IMPORTANCECheckpoint inhibitors targeting programmed cell death 1 or its ligand (PD-L1) as monotherapies or in combination with anti-cytotoxic T-lymphocyte-associated antigen 4 have shown clinical activity in patients with metastatic non-small cell lung cancer.OBJECTIVE To compare durvalumab, with or without tremelimumab, with chemotherapy as a first-line treatment for patients with metastatic non-small cell lung cancer. DESIGN, SETTING, AND PARTICIPANTSThis open-label, phase 3 randomized clinical trial (MYSTIC) was conducted at 203 cancer treatment centers in 17 countries. Patients with treatment-naive, metastatic non-small cell lung cancer who had no sensitizing EGFR or ALK genetic alterations were randomized to receive treatment with durvalumab, durvalumab plus tremelimumab, or chemotherapy. Data were collected from July 21, 2015, to October 30, 2018.INTERVENTIONS Patients were randomized (1:1:1) to receive treatment with durvalumab (20 mg/kg every 4 weeks), durvalumab (20 mg/kg every 4 weeks) plus tremelimumab (1 mg/kg every 4 weeks, up to 4 doses), or platinum-based doublet chemotherapy. MAIN OUTCOMES AND MEASURESThe primary end points, assessed in patients with Ն25% of tumor cells expressing PD-L1, were overall survival (OS) for durvalumab vs chemotherapy, and OS and progression-free survival (PFS) for durvalumab plus tremelimumab vs chemotherapy. Analysis of blood tumor mutational burden (bTMB) was exploratory.

Background: PD1 inhibitors as well as PD1/CTLA4 combinations have shown remarkable efficacy in the first-line treatment of metastatic melanoma. The impact of many concomitant medications on the clinical outcomes from PD1 based therapies remains elusive. Methods: We retrospectively analyzed 140 patients included in the Checkmate 069 phase II clinical trial as a discovery cohort, comparing ipilimumab monotherapy with ipilimumab combined with nivolumab. We compared response rates, progression-free survival and overall survival of patients treated or not with 11 different classes of comedications at immune therapy initiation. Disease stage, LDH levels, BRAF status, sex, age, and body mass index were also compared. Furthermore, a protein array was performed for 440 analytes in a subset of 135 patients for whom pretreatment serum was available. We validated the impact of proton pump inhibitors in an independent cohort of 68 PD1 monotherapy (pembrolizumab or nivolumab) treated patients. Results: In univariate analysis, baseline proton pump inhibitor treatment almost halved the objective response rates, reduced progression-free and overall survival of patients treated with ipilimumab and nivolumab but not with ipilimumab alone. This effect was maintained when accounted for multiple comparisons and in a multivariate analysis. Pretreatment serum protein analysis showed increased NCAM1 and CSF3R levels in PPI users. We found increased baseline blood leukocyte and neutrophil levels in correlation with PPI use. The results were confirmed in an independent cohort of 68, first-line melanoma patients. Conclusions: Our analysis shows that proton pump inhibitors could negatively impact on the benefit from PD1 based therapies both for monotherapy and also for ipilimumab and nivolumab combination therapy. PPIs might establish a unique inflammatory immune status, prior to immune therapy initiation that interferes with treatment efficacy. These results suggest that if possible PPIs should be avoided in patients who are destined for PD1-based immunetherapies. Also, the results will have important implication for design of future clinical trials.

GD and CD produced similar efficacy and toxicity profiles consistent with prior clinical experience.

Abstract Mixtures of Polya trees offer a very flexible nonparametric approach for modelling time-to-event data. Many such settings also feature spatial association that requires further sophistication, either at the point level or at the lattice level. In this paper, we combine these two aspects within three competing survival models, obtaining a data analytic approach that remains computationally feasible in a fully hierarchical Bayesian framework using Markov chain Monte Carlo methods. We illustrate our proposed methods with an analysis of spatially oriented breast cancer survival data from the Surveillance, Epidemiology and End Results program of the National Cancer Institute. Our results indicate appreciable advantages for our approach over competing methods that impose unrealistic parametric assumptions, ignore spatial association or both.

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Background: Mutations in PIEZO1 cause human lymphatic malformations. We have previously uncovered an Orai1-mediated mechanotransduction pathway that triggers lymphatic sprouting through Notch downregulation in response to fluid flow. However, the identity of its upstream mechanosensor remains unknown. This study aimed to identify and characterize the molecular sensor that translates the flow-mediated external signal to the Orai1-regulated lymphatic expansion. Methods: Various mutant mouse models, cellular, biochemical, and molecular biology tools, and a mouse tail lymphedema model were employed to elucidate the role of Piezo1 in flow-induced lymphatic growth and regeneration. Results: Piezo1 was found to be abundantly expressed in lymphatic endothelial cells. Piezo1 knockdown in cultured lymphatic endothelial cells inhibited the laminar flow-induced calcium influx and abrogated the flow-mediated regulation of the Orai1 downstream genes, such as Klf2 , Dtx1 , Dtx3L , and Notch1 , which are involved in lymphatic sprouting. Conversely, stimulation of Piezo1 activated the Orai1-regulated mechanotransduction in the absence of fluid flow. Piezo1-mediated mechanotransduction was significantly blocked by Orai1 inhibition, establishing the epistatic relationship between Piezo1 and Orai1. Lymphatic-specific conditional Piezo1 knockout largely phenocopied sprouting defects shown in Orai1- or Klf2- knockout lymphatics during embryo development. Postnatal deletion of Piezo1 induced lymphatic regression in adults. Ectopic Dtx3L expression rescued the lymphatic defects caused by Piezo1 knockout, affirming that the Piezo1 promotes lymphatic sprouting through Notch downregulation. Consistently, transgenic Piezo1 expression or pharmacological Piezo1 activation enhanced lymphatic sprouting. Finally, we assessed a potential therapeutic value of Piezo1 activation in lymphatic regeneration and found that a Piezo1 agonist, Yoda1, effectively suppressed postsurgical lymphedema development. Conclusions: Piezo1 is an upstream mechanosensor for the lymphatic mechanotransduction pathway and regulates lymphatic growth in response to external physical stimuli. Piezo1 activation presents a novel therapeutic opportunity for preventing postsurgical lymphedema. The Piezo1-regulated lymphangiogenesis mechanism offers a molecular basis for Piezo1-associated lymphatic malformation in humans.

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Kaposi sarcoma is the most common cancer in human immunodeficiency virus-positive individuals and is caused by Kaposi sarcoma-associated herpesvirus (KSHV). It is believed that a small number of latently infected Kaposi sarcoma tumor cells undergo spontaneous lytic reactivation to produce viral progeny for infection of new cells. Here, we use matched donor-derived human dermal blood and lymphatic endothelial cells (BEC and LEC, respectively) to show that KSHV-infected BECs progressively lose viral genome as they proliferate. In sharp contrast, KSHV-infected LECs predominantly entered lytic replication, underwent cell lysis, and released new virus. Continuous lytic cell lysis and de novo infection allowed LEC culture to remain infected for a prolonged time. Because of the strong propensity of LECs toward lytic replication, LECs maintained virus as a population, despite the death of individual host cells from lytic lysis.The master regulator of lymphatic development, Prox1, bound the promoter of the RTA gene to upregulate its expression and physically interacted with RTA protein to coregulate lytic genes. Thus, LECs may serve as a proficient viral reservoir that provides viral progeny for continuous de novo infection of tumor origin cells, and potentially BECs and mesenchymal stem cells, which give rise to Kaposi sarcoma tumors. Our study reveals drastically different host cell behaviors between BEC and LEC and defines the underlying mechanisms of the lymphatic cell environment supporting persistent infection in Kaposi sarcoma tumors.Significance: This study defines the mechanism by which Kaposi's sarcoma could be maintained by virus constantly produced by lymphatic cells in HIV-positive individuals.