Background The pathophysiology of COVID-19 includes immune-mediated hyperinflammation, which could potentially lead to respiratory failure and death. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is among cytokines that contribute to the inflammatory processes. Lenzilumab, a GM-CSF neutralising monoclonal antibody, was investigated in the LIVE-AIR trial to assess its efficacy and safety in treating COVID-19 beyond available treatments. Methods In LIVE-AIR, a phase 3, randomised, double-blind, placebo-controlled trial, hospitalised adult patients with COVID-19 pneumonia not requiring invasive mechanical ventilation were recruited from 29 sites in the USA and Brazil and were randomly assigned (1:1) to receive three intravenous doses of lenzilumab (600 mg per dose) or placebo delivered 8 h apart. All patients received standard supportive care, including the use of remdesivir and corticosteroids. Patients were stratified at randomisation by age and disease severity. The primary endpoint was survival without invasive mechanical ventilation to day 28 in the modified intention-to-treat population (mITT), comprising all randomised participants who received at least one dose of study drug under the documented supervision of the principal investigator or sub-investigator. Adverse events were assessed in all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov , NCT04351152 , and is completed. Findings Patients were enrolled from May 5, 2020, until Jan 27, 2021. 528 patients were screened, of whom 520 were randomly assigned and included in the intention-to-treat population. 479 of these patients (n=236, lenzilumab; n=243, placebo) were included in the mITT analysis for the primary outcome. Baseline demographics were similar between groups. 311 (65%) participants were males, mean age was 61 (SD 14) years at baseline, and median C-reactive protein concentration was 79 (IQR 41–137) mg/L. Steroids were administered to 449 (94%) patients and remdesivir to 347 (72%) patients; 331 (69%) patients received both treatments. Survival without invasive mechanical ventilation to day 28 was achieved in 198 (84%; 95% CI 79–89) participants in the lenzilumab group and in 190 (78%; 72–83) patients in the placebo group, and the likelihood of survival was greater with lenzilumab than placebo (hazard ratio 1·54; 95% CI 1·02–2·32; p=0·040). 68 (27%) of 255 patients in the lenzilumab group and 84 (33%) of 257 patients in the placebo group experienced at least one adverse event that was at least grade 3 in severity based on CTCAE criteria. The most common treatment-emergent adverse events of grade 3 or higher were related to respiratory disorders (26%) and cardiac disorders (6%) and none led to death. Interpretation Lenzilumab significantly improved survival without invasive mechanical ventilation in hospitalised patients with CO...

We examined the activity of ΔF508 cystic fibrosis transmembrane conductance regulator (CFTR) stably expressed in polarized cystic fibrosis bronchial epithelial cells (CFBE41o−) human airway cells and Fisher Rat Thyroid (FRT) cells following treatment with low temperature and a panel of small molecule correctors of ΔF508 CFTR misprocessing. Corr-4a increased ΔF508 CFTR-dependent Cl− conductance in both cell types, whereas treatment with VRT-325 or VRT-640 increased activity only in FRT cells. Total currents stimulated by forskolin and genistein demonstrated similar dose/response effects to Corr-4a treatment in each cell type. When examining the relative contribution of forskolin and genistein to total stimulated current, CFBE41o− cells had smaller forskolin-stimulated Isc following either low temperature or corr-4a treatment (10–30% of the total Isc produced by the combination of both CFTR agonists). In contrast, forskolin consistently contributed greater than 40% of total Isc in ΔF508 CFTR expressing FRT cells corrected with low temperature, and corr-4a treatment preferentially enhanced forskolin dependent currents only in FRT cells (60% of total Isc). ΔF508 CFTR cDNA transcript levels, ΔF508 CFTR C band levels, or cAMP signaling did not account for the reduced forskolin response in CFBE41o− cells. Treatment with non-specific inhibitors of phosphodiesterases (papaverine) or phosphatases (endothall) did not restore ΔF508 CFTR activation by forskolin in CFBE41o− cells, indicating that the Cl− transport defect in airway cells is distal to cAMP or its metabolism. The results identify important differences in ΔF508 CFTR activation in polarizing epithelial models of CF, and have important implications regarding detection of rescued of ΔF508 CFTR in vivo.

These results show that GA treatment may decrease both lesion inflammation and the rate of brain atrophy in RR-MS.

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Therapies to correct the DF508 cystic fibrosis transmembrane conductance regulator (CFTR) folding defect require sensitive methods to detect channel activity in vivo. The b 2 adrenergic receptor agonists, which provide the CFTR stimuli commonly used in nasal potential difference assays, may not overcome the channel gating defects seen in DF508 CFTR after plasma membrane localization. In this study, we identify an agent, quercetin, that enhances the detection of surface DF508 CFTR, and is suitable for nasal perfusion. A screen of flavonoids in CFBE41o 2 cells stably transduced with DF508 CFTR, corrected to the cell surface with low temperature growth, revealed that quercetin stimulated an increase in the shortcircuit current. This increase was dose-dependent in both Fisher rat thyroid and CFBE41o 2 cells. High concentrations inhibited Cl 2 conductance. In CFBE41o 2 airway cells, quercetin (20 mg/ml) activated DF508 CFTR, whereas the b 2 adrenergic receptor agonist isoproterenol did not. Quercetin had limited effects on cAMP levels, but did not produce detectable phosphorylation of the isolated CFTR R-domain, suggesting an activation independent of channel phosphorylation. When perfused in the nares of Cftr 1 mice, quercetin (20 mg/ml) produced a hyperpolarization of the potential difference that was absent in Cftr 2/2 mice. Finally, quercetin-induced, dosedependent hyperpolarization of the nasal potential difference was also seen in normal human subjects. Quercetin activates CFTRmediated anion transport in respiratory epithelia in vitro and in vivo, and may be useful in studies intended to detect the rescue of DF508 CFTR by nasal potential difference.