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Efflux transporters of the RND family confer resistance to multiple antibiotics in Gram-negative bacteria. Here, the authors identify pyridylpiperazine-based compounds that potentiate antibiotic activity in E. coli through allosteric inhibition of its primary RND transporter.

Antimicrobial resistance (AMR) has become a major problem in public health leading to an estimated 4.95 million deaths in 2019. The selective pressure caused by the massive and repeated use of antibiotics has led to bacterial strains that are partially or even entirely resistant to known antibiotics. AMR is caused by several mechanisms, among which the (over)expression of multidrug efflux pumps plays a central role. Multidrug efflux pumps are transmembrane transporters, naturally expressed by Gram-negative bacteria, able to extrude and confer resistance to several classes of antibiotics. Targeting them would be an effective way to revive various options for treatment. Many efflux pump inhibitors (EPIs) have been described in the literature; however, none of them have entered clinical trials to date. This review presents eight families of EPIs active against Escherichia coli or Pseudomonas aeruginosa. Structure–activity relationships, chemical synthesis, in vitro and in vivo activities, and pharmacological properties are reported. Their binding sites and their mechanisms of action are also analyzed comparatively.

Gram‐negative bacteria are intrinsically resistant against cytotoxic substances by means of their outer membrane and a network of multidrug efflux systems, acting in synergy. Efflux pumps from various superfamilies with broad substrate preferences sequester and pump drugs across the inner membrane to supply the highly polyspecific and powerful tripartite resistance–nodulation–cell division (RND) efflux pumps with compounds to be extruded across the outer membrane barrier. In Escherichia coli, the tripartite efflux system AcrAB–TolC is the archetype RND multiple drug efflux pump complex. The homotrimeric inner membrane component acriflavine resistance B (AcrB) is the drug specificity and energy transduction center for the drug/proton antiport process. Drugs are bound and expelled via a cycle of mainly three consecutive states in every protomer, constituting a flexible alternating access channel system. This review recapitulates the molecular basis of drug and inhibitor binding, including mechanistic insights into drug efflux by AcrB. It also summarizes 17 years of mutational analysis of the gene acrB, reporting the effect of every substitution on the ability of E. coli to confer resistance toward antibiotics (http://goethe.link/AcrBsubstitutions). We emphasize the functional robustness of AcrB toward single‐site substitutions and highlight regions that are more sensitive to perturbation. [ABSTRACT FROM AUTHOR]

Coronavirus genome replication and expression are mediated by the viral replication-transcription complex (RTC) which is assembled from multiple nonstructural proteins (nsp). Among these, nsp12 represents the central functional subunit. It harbors the RNA-directed RNA polymerase (RdRp) domain and contains, at its N terminus, an additional domain called NiRAN which is widely conserved in coronaviruses and other nidoviruses. In this study, we produced bacterially expressed coronavirus nsp12s to investigate and compare NiRAN-mediated NMPylation activities from representative alpha- and betacoronaviruses. We found that the four coronavirus NiRAN domains characterized to date have a number of conserved properties, including (i) robust nsp9-specific NMPylation activities that appear to operate largely independently of the C-terminal RdRp domain, (ii) nucleotide substrate preference for UTP followed by ATP and other nucleotides, (iii) dependence on divalent metal ions, with Mn 2+ being preferred over Mg 2+ , and (iv) a key role of N-terminal residues (particularly Asn2) of nsp9 for efficient formation of a covalent phosphoramidate bond between NMP and the N-terminal amino group of nsp9. In this context, a mutational analysis confirmed the conservation and critical role of Asn2 across different subfamilies of the family Coronaviridae , as shown by studies using chimeric coronavirus nsp9 variants in which six N-terminal residues were replaced with those from other corona-, pito- and letovirus nsp9 homologs. The combined data of this and previous studies reveal a remarkable degree of conservation among coronavirus NiRAN-mediated NMPylation activities, supporting a key role of this enzymatic activity in viral RNA synthesis and processing. IMPORTANCE There is strong evidence that coronaviruses and other large nidoviruses evolved a number of unique enzymatic activities, including an additional RdRp-associated NiRAN domain, that are conserved in nidoviruses but not in most other RNA viruses. Previous studies of the NiRAN domain mainly focused on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and suggested different functions for this domain, such as NMPylation/RNAylation of nsp9, RNA guanylyltransferase activities involved in canonical and/or unconventional RNA capping pathways, and other functions. To help resolve partly conflicting information on substrate specificities and metal ion requirements reported previously for the SARS-CoV-2 NiRAN NMPylation activity, we extended these earlier studies by characterizing representative alpha- and betacoronavirus NiRAN domains. The study revealed that key features of NiRAN-mediated NMPylation activities, such as protein and nucleotide specificity and metal ion requirements, are very well conserved among genetically divergent coronaviruses, suggesting potential avenues for future antiviral drug development targeting this essential viral enzyme., Competing Interests: The authors declare no conflict of interest.

Artificial intelligence is creating another new frontier in real-world evidence gathering and analysis. AI's algorithms can approximate-and maybe even surpass-human cognition and judgment in the analysis of complex medical data. Sure, humans will sign off, but AI software will do the heavy lifting.

Effective treatment has helped curb the epidemic, but practical cures have been elusive. Now being tested: a "sterilizing cure" that eradicates HIV from the body, and a "functional cure" that effectively reduces the viral load so it cannot be transmitted or progress to AIDS.

The FDA's approval criteria require a biosimilar to be highly similar to its original biologic and show "no clinically meaningful differences." But mere similarity is not close enough for many clinicians and some patients; it makes biosimilars seem riskier than the original biologics.

Companies with originator biologics on the market have used a variety of regulatory and legal tricks to fend off biosimilars and keep the revenue generated by their products pouring in. The most common approach has been for the "originators" to take legal action to assert or defend the patents attached to their products.

The credibility of cannabis as a source of a legitimate pharmaceutical ingredient in prescription medications took a major step forward in 2018 when the FDA approved Epidiolex (cannabidiol) for two types of severe seizures. Epidiolex was a stellar candidate for approval. It reduced convulsive seizures by about 40% and has a good safety profile.

Pharma says rebates are a primary driver of high drug prices because drug companies raise prices in response to payers' demands for rebates in exchange for preferred placement on their formularies. PBMs and payers object. They say the rebates they get from drugmakers are largely passed on to health plans and patients and save consumers billions of dollars in the form of lower premiums and copays.

Sanofi and Regeneron's Dupixent (dupilumab)-which is already approved for atopic dermatitis-has an FDA action date of October 20 for its asthma indication. It will join Nucala, (mepolizumab), Cinqair (reslizumab), and Fasenra (benralizumab) as a monoclonal antibody approved as a treatment for the type 2 inflammation phenotype in severe asthma.

But the adoption of new technology is rarely smooth; learning curves create jagged edges. The gee-whiz factor of technology can easily get ahead of true utility and effectiveness. And, of course, there's the expense. Hospitals and other providers need to be ready to plow millions in new machines.

Aimovig (erenumab-aooe), codeveloped by Amgen and Novartis, has been recently approved for the prevention of migraines. Its mechanism of action is different than other migraine medications. But perhaps more interestingly, it is the first drug recently developed specifically for migraine prevention.

They take the brakes off the immune system so it attacks cancer cells. But many people don't respond to checkpoint inhibitors, so researchers are looking for ways to defeat the resistance.

The direct-acting virals revolutionized the treatment of hepatitis C. They also ushered turbocharged pricing. At least patients-and society-got a major health benefit in return.

The randomized controlled trial reigns supreme, but the FDA is working on ways to incorporate real-world evidence into its approval processes.

In theory, this approach could help untangle some knotty cost and quality concerns about medications as they move from clinical trials and into clinical use. But there's a credibility issue: The perception that much of the research is biased and that the studies are designed so the results serve the interests of the sponsors.

Some say gene editing platforms like CRISPR are a truer version of gene therapy because they are designed to home in on a particular genomic location.

Opioids remain the go-to products because they target the mu opioid receptor, which has been shown to be the most effective pathway to reduce pain. The holy grail for drug developers is an agent that stifles pain without producing the euphoria and addiction of opioids.

Seven biosimilars have crossed the FDA-approval finish line. The FDA has largely held to the abbreviated pathway it laid out originally. The big change is that the rest of the world is starting to understand it. Approvals are based upon "the totality of evidence," "analytic similarity," and clinical performance with much less emphasis placed on phase 3 trials.

Otezla-the generic name is apremilast-also exploited a new mechanism of action as the first inhibitor of phosphodiesterase 4 (PDE4) that results in increased expression of both anti-inflammatory proteins and reduced expression of their pro-inflammatory counterparts.

Truvada is getting a new lease on life as a preventive agent. It is the only drug approved to prevent HIV infections, and Truvada is the key pharmaceutical component of pre-exposure prophylaxis, which is aimed at preventing, rather than treating, HIV infection and transmission.

Some industry observers wonder why the wunderkind hasn't done more wonderfully on the market. As a brand name drug, Entresto costs substantially more than the generic ACE inhibitors and ARBs. GoodRx reports the average cash price for uninsured patients for Entresto is $504 per month, compared with $44 for enalapril.

The link between diabetes and cardiovascular disease has been clear for decades, but until 2015 no clinical trial had convincingly demonstrated a link between medications that lower blood glucose and cardiovascular risks. Enter SGKT2 inhibitors and GLP-1 agonists.

RWE is a relatively new kid on the block. How exactly it will fit into the complicated world of cancer drug testing, approval, regulation, and marketing is uncertain. The randomized clinical trial has been the gold standard in oncology research for decades and will remain so for the foreseeable future.

Approval of Merck's checkpoint inhibitor is further evidence that cancer treatment decisions are increasingly dependent on the PD-L1 biomarker and other molecular-level differences in tumor cells. But testing for PD-L1 is tricky, and variations in the concentration of PD-L1 cells in different regions of the sample can produce different test results.

At last, there's a biosimilar-like competitor in the U.S. insulin market. Can Basaglar put some downward pressure on prices?

The future of biosimilars in this country is nothing if not uncertain. Most immediately, the U.S. Supreme Court is hearing a case that will determine the timing of the 180-day waiting period before a biosimilar can go on the market. But there are larger and longer-term issues at play as well.

The biosimilar segment of the pharmaceutical industry is on fire. Some 700 biosimilars are at some stage of development, and more than 660 companies are involved in some way in the biosimilars land rush. Still, only a handful may get on the market in the next few years.

The measures most often used today to assess care quality are process measures. Actual outcomes, of course, are harder to measure than whether a certain action has been taken-checking the feet of a patient with diabetes, for example. But many experts don't think process measures get at the heart of quality.

There is momentum building to use observational studies to investigate the safety and efficacy of medications in new ways. Drug companies are using them to establish the value of medicines in negotiating prices, rebates, and formulary placement with payers.

No matter how you slice it, 2016 was a banner year for biosimilars. Still, the high-stakes marketing, regulatory, and legal combat between originators and biosimilars is a long way from over. So far, the originators have been able to hold their ground and thwart the launch of biosimilars with patent lawsuits.