Clinical and laboratory evaluation of patients with SARS-CoV-2 pneumonia treated with high-titer convalescent plasma: a prospective study

OBJECTIVESTo determine the rate of intubation, overall survival, viral clearance, and the development of endogenous antibodies in patients with COVID-19 pneumonia treated with convalescent plasma containing high levels of neutralizing anti-SARS-CoV-2 antibodies. We also aimed to describe the laboratory parameters of the plasma products. DESIGNThis was a phase IIa, single institution, prospective study in adults hospitalized with SARS-CoV-2 pneumonia. SETTINGHackensack University Medical Center, a 770-bed research and teaching hospital located in Bergen County NJ, 11 km from New York City. The study was conducted between April 15 and June 18, 2020. PARTICIPANTS47 hospitalized adult patients were treated: 32 in the non-mechanically ventilated group and 15 in the mechanically ventilated group. All patients had confirmed SARS-CoV-2 pneumonia by radiographic and laboratory evaluation. INTERVENTIONFresh or frozen convalescent plasma from donors with high titers of viral neutralizing antibodies was administered. MAIN OUTCOME MEASURESIncidence of intubation, overall survival, and discharge rate of patients divided in cohorts based on severity of disease. Description of infused plasma characteristics. Evaluation of recipients pre-treatment viral immunity, immunity transfer from convalescent plasma administration, and late immunity 30 and 60 days after treatment. Rates of viral clearance by nasopharyngeal PCR at 10 and 30 days. Outcomes of patients with no pre-treatment immunity. Survival comparison with institutional data for each cohort. RESULTSAnalysis for the non-mechanically ventilated patients showed an intubation rate of 15.6% (95% CI: 5.3%-32.8%) and a day-30 survival rate of 87.5% (28/32; 95% CI:70.2%-96.4%). The overall survival for a comparative group based on institutional data was 66% (675/1023; p=0.012). The rates of negative nasopharyngeal swab by PR-PCR on day+10 and +30 post treatment were 42.9% (95% CI: 24%-63%) and 78% (95% CI: 56%-93%) respectively. Patients mechanically ventilated had a day-30 mortality of 46.7% (95% CI:21.3%-73.4%); the mortality for a comparative group based on institutional data was 68.5% (217/317; p=0.093). The rates of negative nasopharyngeal swab by PR-PCR at day+10 and +30 was 85.7% (95% CI: 42-100%; n=7) and 100% (95% CI: 63-100%; n=8). Seven patients (15%) had no pre-infusion immunity, and all were found to have anti-SARS-CoV-2 neutralizing titers three days post infusion. All evaluable patients were found to have neutralizing antibodies on day+30 (n=30) and on day+60 (n=12) post treatment. There was no difference in outcomes within the ranges of high antiviral neutralizing titers used, mostly greater than 1:1000. There was also no difference between fresh or frozen plasma. The only adverse event was a mild rash in one patient. CONCLUSIONIn this study of adult patients hospitalized with SARS-CoV-2 pneumonia, convalescent plasma was safe and conferred effective transfer of immunity while preserving endogenous immune response. Intubation rates, survival rates compared with institutional data, and viral clearance rates, support the continued evaluation of this antiviral modality. STUDY REGISTRATIONClinicalTrials.gov NTC04343755

Discovery of Isoxazole Amides as Potent and Selective SMYD3 Inhibitors.

We report herein the discovery of isoxazole amides as potent and selective SET and MYND Domain-Containing Protein 3 (SMYD3) inhibitors. Elucidation of the structure-activity relationship of the high-throughput screening (HTS) lead compound 1 provided potent and selective SMYD3 inhibitors. The SAR optimization, cocrystal structures of small molecules with SMYD3, and mode of inhibition (MOI) characterization of compounds are described. The synthesis and biological and pharmacokinetic profiles of compounds are also presented.

Long residence time inhibition of EZH2 in activated polycomb repressive complex 2.

EZH2/PRC2 catalyzes transcriptionally repressive methylation at lysine 27 of histone H3 and has been associated with numerous cancer types. Point mutations in EZH2 at Tyr641 and Ala677 identified in non-Hodgkin lymphomas alter substrate specificity and result in increased trimethylation at histone H3K27. Interestingly, EZH2/PRC2 is activated by binding H3K27me3 marks on histones, and this activation is proposed as a mechanism for self-propagation of gene silencing. Recent work has identified GSK126 as a potent, selective, SAM-competitive inhibitor of EZH2 capable of globally decreasing H3K27 trimethylation in cells. Here we show that activation of PRC2 by an H3 peptide trimethylated at K27 is primarily an effect on the rate-limiting step (kcat) with no effect on substrate binding (Km). Additionally, GSK126 is shown to have a significantly longer residence time of inhibition on the activated form of EZH2/PRC2 as compared to unactivated EZH2/PRC2. Overall inhibition constant (Ki*) values for GSK126 were determined to be as low as 93 pM and appear to be driven by slow dissociation of inhibitor from the activated enzyme. The data suggest that activation of EZH2 allows the enzyme to adopt a conformation that possesses greater affinity for GSK126. The long residence time of GSK126 may be beneficial in vivo and may result in durable target inhibition after drug systemic clearance.