Garbage in, garbage out: how reliable training data improved a virtual screening approach against SARS-CoV-2 MPro

Introduction: The identification of chemical compounds that interfere with SARS-CoV-2 replication continues to be a priority in several academic and pharmaceutical laboratories. Computational tools and approaches have the power to integrate, process and analyze multiple data in a short time. However, these initiatives may yield unrealistic results if the applied models are not inferred from reliable data and the resulting predictions are not confirmed by experimental evidence.Methods: We undertook a drug discovery campaign against the essential major protease (MPro) from SARS-CoV-2, which relied on an in silico search strategy –performed in a large and diverse chemolibrary– complemented by experimental validation. The computational method comprises a recently reported ligand-based approach developed upon refinement/learning cycles, and structure-based approximations. Search models were applied to both retrospective (in silico) and prospective (experimentally confirmed) screening.Results: The first generation of ligand-based models were fed by data, which to a great extent, had not been published in peer-reviewed articles. The first screening campaign performed with 188 compounds (46 in silico hits and 100 analogues, and 40 unrelated compounds: flavonols and pyrazoles) yielded three hits against MPro (IC50 ≤ 25 μM): two analogues of in silico hits (one glycoside and one benzo-thiazol) and one flavonol. A second generation of ligand-based models was developed based on this negative information and newly published peer-reviewed data for MPro inhibitors. This led to 43 new hit candidates belonging to different chemical families. From 45 compounds (28 in silico hits and 17 related analogues) tested in the second screening campaign, eight inhibited MPro with IC50 = 0.12–20 μM and five of them also impaired the proliferation of SARS-CoV-2 in Vero cells (EC50 7–45 μM).Discussion: Our study provides an example of a virtuous loop between computational and experimental approaches applied to target-focused drug discovery against a major and global pathogen, reaffirming the well-known “garbage in, garbage out” machine learning principle

Clinical outcomes of castration-resistant prostate cancer treatments administered as third or fourth line following failure of docetaxel and other second-line treatment: Results of an Italian multicentre study

Background: The availability of new agents (NAs) active in patients with metastatic castration-resistant prostate cancer (mCRPC) progressing after docetaxel treatment (abiraterone acetate, cabazitaxel, and enzalutamide) has led to the possibility of using them sequentially to obtain a cumulative survival benefit. Objective: To provide clinical outcome data relating to a large cohort of mCRPC patients who received a third-line NA after the failure of docetaxel and another NA. Design, setting, and participants: We retrospectively reviewed the clinical records of patients who had received at least two successive NAs after the failure of docetaxel. Outcome measurements and statistical analysis: The independent prognostic value of a series of pretreatment covariates on the primary outcome measure of overall survival was assessed using Cox regression analysis. Results and limitations: Weassessed260patientswhoreceivedonethird-lineNAbetween January 2012 and December 2013, including 38 who received a further NA as fourth-line therapy. The median progression-free and overall survival from the start of third-line therapy was, respectively, 4 mo and 11 mo, with no significant differences between the NAs. Performance status, and haemoglobin and alkaline phosphatase levels were the only independent prognostic factors. The limitations of the study are mainly due its retrospective nature and the small number of patients treatedwith some of the sequences. Conclusions: We were unable to demonstrate a difference in the clinical outcomes of third-line NAs regardless of previous NA therapy. Patient summary: It is debated which sequence of treatments to adopt after docetaxel. Our data do not support the superiority of any of the three new agents in third-line treatment, regardless of the previously administered new agent

Identification of conical structures in small aluminum oxide clusters: Infrared spectroscopy of (al2o3)(1-4)(alo)(+)

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