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Multi-institutional, prospective, randomized, double-blind, placebo-controlled phase IIb trial of the tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine to prevent recurrence in high-risk melanoma patients: A subgroup analysis
Background: Checkpoint inhibitors (CPI) in combination with cell-based vaccines may produce synergistic antitumor immunity. The primary analysis of the randomized and blinded phase IIb trial in resected stage III/IV melanoma demonstrated TLPLDC is safe and improved 24-month disease-free survival (DFS) in the per treatment (PT) analysis. Here, we examine efficacy within pre-specified and exploratory subgroups. Methods: Stage III/IV patients rendered disease-free by surgery were randomized 2:1 to TLPLDC vaccine versus placebo. The pre-specified PT analysis included only patients completing the primary vaccine/placebo series at 6 months. KaplanâMeier analysis was used to compare 24-month DFS among subgroups. Results: There were no clinicopathologic differences between subgroups except stage IV patients were more likely to receive CPI. In stage IV patients, 24-month DFS was 43% for vaccine versus 0% for placebo (p = 0.098) in the ITT analysis and 73% versus 0% (p = 0.002) in the PT analysis. There was no significant difference in 24-month DFS when stratified by use of immunotherapy or CPI. For patients with resected recurrent disease, 24-month DFS was 88.9% versus 33.3% (p = 0.013) in the PT analysis. All benefit from vaccination was in the PT analysis; no benefit was found in patients receiving up to three doses. Conclusion: The TLPLDC vaccine improved DFS in patients completing the primary vaccine series, particularly in the resected stage IV patients. The efficacy of the TLPLDC vaccine will be confirmed in a phase III study evaluating adjuvant TLPLDC + CPI versus Placebo + CPI in resected stage IV melanoma patients. © 2021 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Status of the UCN experiment
International audienceThe neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics beyond the standard model. Measurements of neutron lifetime and ÎČ-decay correlation coefficients with precisions of 0.02% and 0.1%, respectively, would allow for stringent constraints on new physics. The UCNÏ experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime, Ïn = 877.7s (0.7s)stat (+0.4/â0.2s)sys. We discuss the recent result from UCNÏ, the status of ongoing data collection and analysis, and the path toward a 0.25Â s measurement of the neutron lifetime with UCNÏ
Status of the UCNÏ experiment
The neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics beyond the standard model. Measurements of neutron lifetime and ÎČ-decay correlation coefficients with precisions of 0.02% and 0.1%, respectively, would allow for stringent constraints on new physics. The UCNÏ experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime, Ïn = 877.7s (0.7s)stat (+0.4/â0.2s)sys. We discuss the recent result from UCNÏ, the status of ongoing data collection and analysis, and the path toward a 0.25Â s measurement of the neutron lifetime with UCNÏ
New result for the neutron -asymmetry parameter from UCNA
International audienceBackground: The neutron ÎČ-decay asymmetry parameter A0 defines the angular correlation between the spin of the neutron and the momentum of the emitted electron. Values for A0 permit an extraction of the ratio of the weak axial-vector to vector coupling constants, λâĄgA/gV, which under assumption of the conserved vector current hypothesis (gV=1) determines gA. Precise values for gA are important as a benchmark for lattice QCD calculations and as a test of the standard model. Purpose: The UCNA experiment, carried out at the Ultracold Neutron (UCN) source at the Los Alamos Neutron Science Center, was the first measurement of any neutron ÎČ-decay angular correlation performed with UCN. This article reports the most precise result for A0 obtained to date from the UCNA experiment, as a result of higher statistics and reduced key systematic uncertainties, including from the neutron polarization and the characterization of the electron detector response. Methods: UCN produced via the downscattering of moderated spallation neutrons in a solid deuterium crystal were polarized via transport through a 7 T polarizing magnet and a spin flipper, which permitted selection of either spin state. The UCN were then contained within a 3-m long cylindrical decay volume, situated along the central axis of a superconducting 1 T solenoidal spectrometer. With the neutron spins then oriented parallel or anti-parallel to the solenoidal field, an asymmetry in the numbers of emitted decay electrons detected in two electron detector packages located on both ends of the spectrometer permitted an extraction of A0. Results: The UCNA experiment reports a new 0.67% precision result for A0 of A0=â0.12054(44)stat(68)syst, which yields λ=gA/gV=â1.2783(22). Combination with the previous UCNA result and accounting for correlated systematic uncertainties produces A0=â0.12015(34)stat(63)syst and λ=gA/gV=â1.2772(20). Conclusions: This new result for A0 and gA/gV from the UCNA experiment has provided confirmation of the shift in values for gA/gV that has emerged in the published results from more recent experiments, which are in striking disagreement with the results from older experiments. Individual systematic corrections to the asymmetries in older experiments (published prior to 2002) were >10%, whereas those in the more recent ones (published after 2002) have been of the scale of <2%. The impact of these older results on the global average will be minimized should future measurements of A0 reach the 0.1% level of precision with central values near the most recent results
Improved limits on Fierz interference using asymmetry measurements from the Ultracold Neutron Asymmetry (UCNA) experiment
International audienceThe Ultracold Neutron Asymmetry (UCNA) experiment was designed to measure the ÎČ-decay asymmetry parameter, A0, for free neutron decay. In the experiment, polarized ultracold neutrons are transported into a decay trap, and their ÎČ-decay electrons are detected with â4Ï acceptance into two detector packages which provide position and energy reconstruction. The experiment also has sensitivity to bn, the Fierz interference term in the neutron ÎČ-decay rate. In this work, we determine bn from the energy dependence of A0 using the data taken during the UCNA 2011â2013 run. In addition, we present the same type of analysis using the earlier 2010 A dataset. Motivated by improved statistics and comparable systematic errors compared to the 2010 data-taking run, we present a new bn measurement using the weighted average of our asymmetry dataset fits, to obtain bn=0.066±0.041stat±0.024syst which corresponds to a limit of â0.012<bn<0.144 at the 90% confidence level
Search for neutron dark decay:
In January, 2018, Fornal and Grinstein proposed that a previously unobserved neutron decay branch to a dark matter particle (Ï) could account for the discrepancy in the neutron lifetime observed in two different types of experiments. One of the possible final states discussed includes a single Ï along with an e+eâ pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ⌠4Ï acceptance using a pair of detectors that observe a volume of stored Ultracold Neutrons (UCNs). We use the timing information of coincidence events to select candidate dark sector particle decays by applying a timing calibration and selecting events within a physically-forbidden timing region for conventional n â p + e- + ÎœÌ
e decays. The summed kinetic energy (Ee+eâ) from such events is reconstructed and used to set limits, as a function of the Ï mass, on the branching fraction for this decay channel
Search for neutron dark decay: nâââÏâ+âe+eâ
In January, 2018, Fornal and Grinstein proposed that a previously unobserved neutron decay branch to a dark matter particle (Ï) could account for the discrepancy in the neutron lifetime observed in two different types of experiments. One of the possible final states discussed includes a single Ï along with an e+eâ pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ⌠4Ï acceptance using a pair of detectors that observe a volume of stored Ultracold Neutrons (UCNs). We use the timing information of coincidence events to select candidate dark sector particle decays by applying a timing calibration and selecting events within a physically-forbidden timing region for conventional n â p + e- + ÎœÌ
e decays. The summed kinetic energy (Ee+eâ) from such events is reconstructed and used to set limits, as a function of the Ï mass, on the branching fraction for this decay channel
Improved limits on Fierz Interference using asymmetry measurements from the UCNA experiment
The Ultracold Neutron Asymmetry (UCNA) experiment was designed to measure the -decay asymmetry parameter, , for free neutron decay. In the experiment, polarized ultracold neutrons are transported into a decay trap, and their -decay electrons are detected with acceptance into two detector packages which provide position and energy reconstruction. The experiment also has sensitivity to , the Fierz interference term in the neutron -decay rate. In this work, we determine from the energy dependence of using the data taken during the UCNA 2011-2013 run. In addition, we present the same type of analysis using the earlier 2010 dataset. Motivated by improved statistics and comparable systematic errors compared to the 2010 data-taking run, we present a new measurement using the weighted average of our asymmetry dataset fits, to obtain which corresponds to a limit of at the 90% confidence level
Final results for the neutron -asymmetry parameter from the UCNA experiment
International audienceThe UCNA experiment was designed to measure the neutron ÎČ-asymmetry parameter A0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7âT magnetic field, and then directed to a 1âT solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008â2009, 2010, and 2011â2013, which ultimately culminated in a 0.67% precision result for A0
Final results for the neutron ÎČ-asymmetry parameter A0 from the UCNA experiment
The UCNA experiment was designed to measure the neutron ÎČ-asymmetry parameter A0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7âT magnetic field, and then directed to a 1âT solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008â2009, 2010, and 2011â2013, which ultimately culminated in a 0.67% precision result for A0