In vitro metabolic characterization of the SARS-CoV-2 papain-like protease inhibitors GRL0617 and HY-17542.

The SARS-CoV-2 pandemic requires a new therapeutic target for viral infection, and papain-like protease (Plpro) has been suggested as a druggable target. This in-vitro study was conducted to examine the drug metabolism of the GRL0617 and HY-17542, Plpro inhibitors. Metabolism of these inhibitors was studied to predict the pharmacokinetics in human liver microsomes. The hepatic cytochrome P450 (CYP) isoforms responsible for their metabolism were identified using recombinant enzymes. The drug-drug interaction potential mediated by cytochrome P450 inhibition was estimated. In human liver microsomes, the Plpro inhibitors had phase I and phase I + II metabolism with half-lives of 26.35 and 29.53 min, respectively. Hydroxylation (M1) and desaturation (-H2, M3) of the para-amino toluene side chain were the predominant reactions mediated with CYP3A4 and CYP3A5. CYP2D6 is responsible for the hydroxylation of the naphthalene side ring. GRL0617 inhibits major drug-metabolizing enzymes, including CYP2C9 and CYP3A4. HY-17542 is structural analog of GRL0617 and it is metabolized to GRL0617 through non-cytochrome P450 reactions in human liver microsomes without NADPH. Like GRL0617 and HY-17542 undergoes additional hepatic metabolism. The in-vitro hepatic metabolism of the Plpro inhibitors featured short half-lives; preclinical metabolism studies are needed to determine therapeutic doses for these inhibitors.

Histological and serological features of acute liver injury after SARS-CoV-2 vaccination

Background & Aims: Liver injury with autoimmune features after vaccination against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is increasingly reported. We investigated a large international cohort of individuals with acute hepatitis arising after SARS-CoV-2 vaccination, focusing on histological and serological features. Methods: Individuals without known pre-existing liver diseases and transaminase levels ≥5x the upper limit of normal within 3 months after any anti-SARS-CoV-2 vaccine, and available liver biopsy were included. Fifty-nine patients were recruited;35 females;median age 54 years. They were exposed to various combinations of mRNA, vectorial, inactivated and protein-based vaccines. Results: Liver histology showed predominantly lobular hepatitis in 45 (76%), predominantly portal hepatitis in 10 (17%), and other patterns in four (7%) cases;seven had fibrosis Ishak stage ≥3, associated with more severe interface hepatitis. Autoimmune serology, centrally tested in 31 cases, showed anti-antinuclear antibody in 23 (74%), anti-smooth muscle antibody in 19 (61%), anti-gastric parietal cells in eight (26%), anti-liver kidney microsomal antibody in four (13%), and anti-mitochondrial antibody in four (13%) cases. Ninety-one percent were treated with steroids ± azathioprine. Serum transaminase levels improved in all cases and were normal in 24/58 (41%) after 3 months, and in 30/46 (65%) after 6 months. One patient required liver transplantation. Of 15 patients re-exposed to SARS-CoV-2 vaccines, three relapsed. Conclusion: Acute liver injury arising after SARS-CoV-2 vaccination is frequently associated with lobular hepatitis and positive autoantibodies. Whether there is a causal relationship between liver damage and SARS-CoV-2 vaccines remains to be established. A close follow-up is warranted to assess the long-term outcomes of this condition. Impact and implications: Cases of liver injury after vaccination against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) have been published. We investigated a large international cohort of individuals with acute hepatitis after SARS-CoV-2 vaccination, focusing on liver biopsy findings and autoantibodies: liver biopsy frequently shows inflammation of the lobule, which is typical of recent injury, and autoantibodies are frequently positive. Whether there is a causal relationship between liver damage and SARS-CoV-2 vaccines remains to be established. Close follow-up is warranted to assess the long-term outcome of this condition. © 2022 The Author(s)

LEPTOSPIROSIS IN THE CITY: A CASE REPORT

CASE: A 58 year-old undomiciled man with no medical history presented with three days of anorexia, malaise, abdominal pain, and decreased urination. Exam was notable for scleral icterus. Lab-work revealed sodium 133 mEq/L, BUN 132mg/dL, creatinine 8.82 mg/dL, platelet 64 K/uL, total bilirubin 6.4 mg/dL, direct bilirubin 5 mg/dL. Lab-work two years prior was normal. HCV antibody was reactive, urinalysis revealed microscopic hematuria, and cocaine was detected on toxicology. Abdominopelvic CT, MRCP and renal sonogram were non-pathologic. On hospital day 5 his creatinine downtrended but total bilirubin continued to rise to a peak of 11.2 mg/dL and a leukocytosis without fever developed (peak 21.2 K/uL). Ceftriaxone was started empirically and a workup of blood cultures, viral serologies, ANA, alpha-1 antitrypsin, complement, cryoglobulin, ceruloplasmin level, microsomal, smooth muscle and antimitochondrial antibodies was normal. Review of his history suggested exposure to rodents as he slept close to a dumpster. Pending Leptospirosis serology, the antibiotics were adjusted to doxycycline. At discharge, the WBC and platelet counts normalized while the bilirubin and creatinine downtrended. IgM serology for leptospira later resulted positive. IMPACT/DISCUSSION: Leptospirosis is a worldwide zoonotic disease commonly associated with moist environments, poor housing and inadequate sanitation. Rodents are important reservoirs, shedding spirochetes through urine. Human infection results from exposure to animal urine, contaminated soil or water, or infected animal tissue. Portals of entry include cuts, mucous membranes or conjunctivae. Person-toperson transmission is rare. The incubation period is 5-14 days and illness severity ranges from subclinical to life-threatening. Disease manifestations include jaundice with acute kidney failure (Weil's disease), rash, conjunctival suffusion, hyponatremia, thrombocytopenia, microscopic hematuria, myocarditis, pulmonary hemorrhage, and meningitis. A biphasic illness, the acute febrile bacteremic phase can last 2-9 days followed by a period of apparent improvement. An “immune” phase then follows characterized by development of complications, as in our patient. During this phase, leptospires are absent from blood but may appear in the urine. While human cases of leptospirosis are rarely reported in the US outside of Puerto Rico and Hawaii (in the absence of travel), there was a significant rise reported to the NYC DOH in 2021. A potential explanation is an increase in housing insecurity and disruptions to waste management as a consequence of the COVID-19 pandemic. CONCLUSION: Leptospirosis is an important consideration in at-risk populations who may unknowingly be exposed due to living conditions. Our case of unexpected Weil's disease in an urban setting underscores the importance of a thorough social history as well as timely recognition of uncommon infections as possible reversible causes of multi- organ failure in the context of a changing world climate.

Hydroxychloroquine is metabolized by CYP2D6, CYP3A4 and CYP2C8, and inhibits CYP2D6, while its metabolites also inhibit CYP3A4 in vitro

Introduction: Hydroxychloroquine is used for the treatment of malaria, rheumatoid arthritis and lupus erythematosus. In 2020, hydroxychloroquine was also repurposed for the treatment of COVID-19. Although current evidence does not encourage the use of hydroxychloroquine to treat COVID-19, its therapeutic and prophylactic use against COVID-19 is still investigated in clinical trials. Despite being in clinical use for more than 60 years, its clinical pharmacology is not well understood. Hydroxychloroquine is metabolized into three active metabolites, but the key metabolizing enzymes have not been unambiguously identified. Moreover, little is known about the inhibitory effects of hydroxychloroquine on cytochrome P450 (CYP) enzymes. Objectives: This study aimed to investigate the CYP metabolic and inhibitory profile of hydroxychloroquine and its three metabolites in vitro. Methods: Hydroxychloroquine metabolism was studied in human liver microsomes (HLM) and recombinant CYP enzymes using substrate depletion and CYP-selective inhibitors. The inhibitory effects of hydroxychloroquine and its metabolites on nine CYP enzymes were also determined in HLM, using automated probe substrate cocktail assays. Results: Based on screening experiments, CYP3A4, CYP2D6 and CYP2C8 were the key enzymes involved in hydroxychloroquine metabolism in vitro. Although the intrinsic clearance (CLint) value of hydroxychloroquine depletion by recombinant CYP2D6 (0.87 μl/min/pmol) was more than 10-fold higher than that by CYP3A4 (0.075 μl/min/pmol), scaling of the recombinant data to HLM level resulted in similar CLint values for CYP2D6 and CYP3A4 (11 and 14 μl/min/mg) because of the much greater abundancy of CYP3A4 than that of CYP2D6. The scaled HLM CLint of CYP2C8 was 5.7 μl/min/mg. Data in HLM with CYPselective inhibitors also suggested relatively equal roles for CYP2D6 and CYP3A4 in hydroxychloroquine metabolism, and a smaller contribution for CYP2C8. In CYP inhibition experiments, hydroxychloroquine and its three metabolites were direct CYP2D6 inhibitors (50% inhibitory concentration IC50 18-135 μM), while all metabolites were CYP3A timedependent inhibitors (IC50 12-117 μM, IC50 shift 2.2-3.4-fold). CYP2D6 inhibition explains the reported clinical drug-drug interaction between hydroxychloroquine and the CYP2D6 substrate metoprolol. The present data, together with the inhibitors' estimated intracellular hepatocyte concentrations, were successfully used in a static model to predict the fold increase in metoprolol AUC (predicted: 2.3- 2.8-fold, observed: 1.65-fold). Conclusion: The present study unambiguously demonstrates that hydroxychloroquine is metabolized mainly by CYP2D6, CYP3A4 and CYP2C8 in vitro. Moreover, hydroxychloroquine and its three metabolites are CYP2D6 reversible inhibitors, and hydroxychloroquine metabolites are CYP3A time-dependent inhibitors. The current data can be used in static and physiologically-based pharmacokinetic models to predict hydroxychloroquine drug-drug interaction potential, as shown with the successful prediction of hydroxychloroquine - metoprolol drug-drug interaction. (Table Presented).

Interspecies Comparisons of the Effects of Potential Antiviral 3-Amidinophenylalanine Derivatives on Cytochrome P450 1A2 Isoenzyme.

In vitro models of animals vulnerable to SARS-CoV-2 infection can support the characterization of effective antiviral drugs, such as synthetic inhibitors of the transmembrane protease serine 2 (TMPRSS2). Changes in cytochrome P450 (CYP) 1A2 activities in the presence of the potential TMPRSS2/matriptase inhibitors (MI) were measured using fluorometric and luminescent assays. Furthermore, the cytotoxicity of these inhibitors was evaluated using the MTS method. In addition, 60 min-long microsomal stability assays were performed using an UPLC-MS/MS procedure to elucidate depletion rates of the inhibitors. CYP1A2 was influenced significantly by MI-463 and MI-1900 in rat microsomes, by MI-432 and MI-482 in beagle microsomes, and by MI-432, MI-463, MI-482, and MI-1900 in cynomolgus monkey microsomes. The IC50 values in monkey microsomes were 1.30 ± 0.14 µM, 2.4 ± 1.4 µM, 0.21 ± 0.09 µM, and 1.1 ± 0.8 µM for inhibitors MI-432, MI-463, MI-482, and MI-1900, respectively. The depletion rates of the parent compounds were lower than 50%, independently of the investigated animal species. The host cell factor TMPRSS2 is of key importance for the cross-species spread of SARS-CoV-2. Studies of the in vitro biotransformation of TMPRSS2 inhibitors provide additional information for the development of new antiviral drugs.

Pre-clinical evaluation of NEOS-223, an (S)-valine-thiazole derived peptidomimetic N-heterocycle, as an anticancer agent and P-glycoprotein inhibitor

The ability to control the proliferation and cell death by inhibiting specific target kinase offers the opportunity to apply targeted therapies in the treatment of cancer. It has been found that (S)-valine-thiazole-derived compounds such as NEOS-223 are effective inhibitors of one or more of these kinases. NEOS 223 was developed, synthesized, and tested in the NCI 60 human tumor cell-screening panel demonstrating inhibition of colon (-53%), melanoma (-41%), and breast cancers (-9%). Microsomal clearance was determined in mouse, rat, dog, and human, and analyzed by LC-MS/MS by percent of parent material. IC50 values for CYP inhibition of >10 μM were calculated for 1A2, 2C19, and 3A4 with IC50 values of 4.86, 4.31, and 7.84 μM for 2C9 and 2D6. Microsomal clearance was high in all species with clearance rates ranging from 69-136 mL/min/kg. Plasma protein binding was determined by Rapid Equilibrium Dialysis in mice, rats, dogs, and humans. High plasma protein binding (>70%) was observed across all species. Based on the NCI results several cell lines were assayed in an MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) to determine cell viability in the presence of NEOS-223 resulting in <20% viability in colon, breast, melanoma, pancreatic and prostate human cancer cell lines at a 10 uM concentration. Maximum tolerated dose studies were conducted by both intraperitoneal and oral administration in mice. NEOS-223 delivered up to 80 mg/kg was well tolerated. Minimal or no toxicity was observed in acute and repeat dose animal studies. Pharmacokinetics of oral administration demonstrated adequate systemic exposure at therapeutic levels in mice, rats, and dogs. Preliminary in vivo mouse xenograft studies were performed on colon (COLO 205, HT-29 red FLUC), breast (MDA-Sumathi Chittamuru;Timothy M. Murphy;Sara A. Little;Andrew A. Taylor;Roseanne Wexler;Laxman Desai MB-468), melanoma (M-14), pancreatic (PANC-1), and prostate (PC3) human cancer cells with significant tumor inhibition observed compared to positive control agent groups with twice daily dosing of NEOS-223. In addition, a five-day pilot oral toxicity study in rats with dose range-finding studies and a 28-day repeat dose toxicity study performed in both rats and dogs provided favorable results. NEOS-223 has demonstrated active in vitro activity along with a favorable safety profile. in vivo efficacy resulted in inhibition of growth of multiple cell line. As a novel effective structure possibly targeting multiple kinases and transporters in one hybrid molecule, NEOS-223 may be a preferred monotherapy or combined therapy for multiple cancers. If upon further development, this drug is effective in humans, it would advance clinical practice and could improve current therapy significantly.