Safety, Tolerability, and Pharmacokinetics of Intravenous Doses of PF-07304814, a Phosphate Prodrug Protease Inhibitor for the Treatment of SARS-CoV-2, in Healthy Adult Participants.

Studies on targeted antivirals for treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the ongoing pandemic, are limited. PF-07304814 (lufotrelvir) is the phosphate prodrug of PF-00835231, a protease inhibitor targeting the 3C-like protease of SARS-CoV-2. This phase 1 study evaluated the safety, tolerability, and pharmacokinetics (PK) of single ascending intravenous doses of lufotrelvir (continuous 24-hour infusion of 50, 150, 500, or 700 mg) versus placebo in healthy volunteers (2 interleaving cohorts: 1, n = 8; 2, n = 7). Each dosing period was separated by a washout interval (≥5 days). Treatment-emergent adverse events, PK, and biomarker concentrations were estimated from plasma/urine samples. Lufotrelvir was administered to 15 volunteers (mean [SD] age 39.7 [11.8] years). No serious adverse events, discontinuations, or deaths were reported. Mean maximum observed concentration of PF-00835231 (active moiety; 97.0 ng/mL to 1288 ng/mL) were observed between median time to maximum concentration of 14 to 16 hours after the start of the lufotrelvir infusion. Near-maximum plasma concentrations of PF-00835231 were observed ≈6 hours after infusion start and sustained until infusion end. PF-00835231 plasma concentrations declined rapidly after infusion end (mean terminal half-life: 500 mg, 2.0 hours; 700 mg, 1.7 hours). Approximately 9%-11% of the dose was recovered in urine as PF-00835231 across doses. A continuous, single-dose, 24-hour infusion of lufotrelvir (50-700 mg) was rapidly converted to PF-00835231 (active moiety), with dose-proportional PK exposures and no significant safety concerns. A daily, 24-hour continuous infusion of 270 to 350 mg is expected to maintain PF-00835231 concentration at steady state/above effective antiviral concentrations. Further studies exploring lufotrelvir efficacy in patients with coronavirus disease 2019 are ongoing.

QT prolongation associated with hydroxychloroquine and protease inhibitors in COVID-19.

WHAT IS KNOWN AND OBJECTIVE: Hydroxychloroquine and protease inhibitors were widely used as off-label treatment options for COVID-19 but the safety data of these drugs among the COVID-19 population are largely lacking. Drug-induced QTc prolongation is a known adverse reaction of hydroxychloroquine, especially during chronic treatment. However, when administered concurrently with potential pro-arrhythmic drugs such as protease inhibitors, the risk of QTc prolongation imposed on these patients is not known. We aim to investigate the incidence of QTc prolongation events and potential factors associated with its occurrence in COVID-19 population. METHODS: We included 446 SARS-CoV-2 RT-PCR-positive patients taking at least one treatment drug for COVID-19 within a period of one month (March-April 2020). In addition to COVID-19-related treatment (HCQ/PI), concomitant drugs with risks of QTc prolongation were considered. We defined QTc prolongation as QTc interval of ≥470 ms in postpubertal males, and ≥480 ms in postpubertal females. RESULTS AND DISCUSSION: QTc prolongation events occurred in 28/446 (6.3%) patients with an incidence rate of 1 case per 100 person-days. A total of 26/28 (93%) patients who had prolonged QTc intervals received at least two pro-QT drugs. Multivariate analysis showed that HCQ and PI combination therapy had five times higher odds of QTc prolongation as compared to HCQ-only therapy after controlling for age, cardiovascular disease, SIRS and the use of concurrent QTc-prolonging agents besides HCQ and/or PI (OR 5.2; 95% CI, 1.11-24.49; p = 0.036). Independent of drug therapy, presence of SIRS resulted in four times higher odds of QTc prolongation (OR 4.3; 95% CI, 1.66-11.06; p = 0.003). In HCQ-PI combination group, having concomitant pro-QT drugs led to four times higher odds of QTc prolongation (OR 3.8; 95% CI, 1.53-9.73; p = 0.004). Four patients who had prolonged QTc intervals died but none were cardiac-related deaths. WHAT IS NEW AND CONCLUSION: In our cohort, hydroxychloroquine monotherapy had low potential to increase QTc intervals. However, when given concurrently with protease inhibitors which have possible or conditional risk, the odds of QTc prolongation increased fivefold. Interestingly, independent of drug therapy, the presence of systemic inflammatory response syndrome (SIRS) resulted in four times higher odds of QTc prolongation, leading to the postulation that some QTc events seen in COVID-19 patients may be due to the disease itself. ECG monitoring should be continued for at least a week from the initiation of treatment.

Safety of protease inhibitors and Arbidol for SARS-CoV-2 pneumonia in Zhejiang Province, China.

The aim of this study was to evaluate the safety of an antiviral regimen of protease inhibitors combined with Arbidol (umifenovir) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia patients. The genomic sequence of SARS-CoV-2 is highly homologous to that of SARS-CoV (Zhou et al., 2020). Previously published basic and clinical research on anti-SARS-CoV treatment found that lopinavir/ritonavir (LPV/r) could improve the prognosis of SARS patients (Chan et al., 2003; Chu et al., 2004). Darunavir (DRV) is another protease inhibitor that blocks the binding of SARS-CoV-2 to human angiotensin-converting enzyme 2 (Omotuyi et al., 2020). The broad-spectrum antiviral drug Arbidol (umifenovir) also shows in vitro anti-SARS-CoV activity (Khamitov et al., 2008).

Structure-Based Screening to Discover New Inhibitors for Papain-like Proteinase of SARS-CoV-2: An In Silico Study.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) expresses a multifunctional papain-like proteinase (PLpro), which mediates the processing of the viral replicase polyprotein. Inhibition of PLpro has been shown to suppress the viral replication. This study aimed to explore new anti-PLpro candidates by applying virtual screening based on GRL0617, a known PLpro inhibitor of SARS coronavirus (SARS-CoV). The three-dimensional (3D) structure of SARS-CoV-2 PLpro was built by homology modeling, using SARS-CoV PLpro as the template. The model was refined and studied through molecular dynamic simulation. AutoDock Vina was then used to perform virtual screening where 50 chemicals with at least 65% similarity to GRL0617 were docked with the optimized SARS-CoV-2 PLpro. In this screening, 5-(aminomethyl)-2-methyl-N-[(1R)-1-naphthalen-1-ylethyl]benzamide outperformed GRL0617 in terms of binding affinity (-9.7 kcal/mol). Furthermore, 2-(4-fluorobenzyl)-5-nitro-1H-isoindole-1,3(2H)-dione (previously introduced as an inhibitor of cyclooxygenase-2), 3-nitro-N-[(1r)-1-phenylethyl]-5-(trifluoromethyl)benzamide (inhibitor against Mycobacterium tuberculosis), as well as the recently introduced SARS-CoV-2 PLpro inhibitor 5-acetamido-2-methyl-N-[(1S)-1-naphthalen-1-ylethyl]benzamide showed promising affinity for the viral proteinase. All of the identified compounds demonstrated an acceptable pharmacokinetic profile. In conclusion, our findings represent rediscovery of analgesic, anti-inflammatory, antibacterial, or antiviral drugs as promising pharmaceutical candidates against the ongoing coronavirus.

Absence of relevant QT interval prolongation in not critically ill COVID-19 patients.

SARS-CoV-2 is a rapidly evolving pandemic causing great morbimortality. Medical therapy with hydroxicloroquine, azitromycin and protease inhibitors is being empirically used, with reported data of QTc interval prolongation. Our aim is to assess QT interval behaviour in a not critically ill and not monitored cohort of patients. We evaluated admitted and ambulatory patients with COVID-19 patients with 12 lead electrocardiogram at 48 h after treatment initiation. Other clinical and analytical variables were collected. Statistical analysis was performed to assess the magnitude of the QT interval prolongation under treatment and to identify clinical, analytical and electrocardiographic risk markers of QT prolongation independent predictors. We included 219 patients (mean age of 63.6 ± 17.4 years, 48.9% were women and 16.4% were outpatients. The median baseline QTc was 416 ms (IQR 404-433), and after treatment QTc was prolonged to 423 ms (405-438) (P < 0.001), with an average increase of 1.8%. Most of the patients presented a normal QTc under treatment, with only 31 cases (14.1%) showing a QTc interval > 460 ms, and just one case with QTc > 500 ms. Advanced age, longer QTc basal at the basal ECG and lower potassium levels were independent predictors of QTc interval prolongation. Ambulatory and not critically ill patients with COVID-19 treated with hydroxychloroquine, azithromycin and/or antiretrovirals develop a significant, but not relevant, QT interval prolongation.

High rate of major drug-drug interactions of lopinavir-ritonavir for COVID-19 treatment.

The impact of drug-drug interactions (DDI) between ritonavir-boosted lopinavir (LPV-r) to treat patients with coronavirus disease 2019 (COVID-19) and commonly used drugs in clinical practice is not well-known. Thus, we evaluated the rate and severity of DDI between LPV-r for COVID-19 treatment and concomitant medications. This was a cross-sectional study including all individuals diagnosed of SARS-CoV-2 infection treated with LPV-r and attended at a single center in Southern Spain (March 1st to April 30th, 2020). The frequency [95% confidence interval (95% CI)] of potential and major DDI were calculated. Overall, 469 patients were diagnosed of COVID-19, 125 (27%) of them were prescribed LPV-r. LPV-r had potential DDI with concomitant medications in 97 (78%, 95% CI 69-85%) patients, and in 33 (26%, 95% CI 19-35%) individuals showed major DDI. Twelve (36%) patients with major DDI and 14 (15%) individuals without major DDI died (p = 0.010). After adjustment, only the Charlson index was independently associated with death [adjusted OR (95% CI) for Charlson index ≥ 5: 85 (10-731), p < 0.001]. LPV-r was discontinued due to side effects in 31 (25%) patients. Management by the Infectious Diseases Unit was associated with a lower likelihood of major DDI [adjusted odds ratio (95% CI): 0.14 (0.04-0.53), p = 0.003). In conclusion, a high frequency of DDI between LPV-r for treating COVID-19 and concomitant medications was found, including major DDI. Patients with major DDI showed worse outcomes, but this association was explained by the older age and comorbidities. Patients managed by the Infectious Diseases Unit had lower risk of major DDI.

Broad-Spectrum Coronavirus Fusion Inhibitors to Combat COVID-19 and Other Emerging Coronavirus Diseases.

In the past 17 years, three novel coronaviruses have caused severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and the coronavirus disease 2019 (COVID-19). As emerging infectious diseases, they were characterized by their novel pathogens and transmissibility without available clinical drugs or vaccines. This is especially true for the newly identified COVID-19 caused by SARS coronavirus 2 (SARS-CoV-2) for which, to date, no specific antiviral drugs or vaccines have been approved. Similar to SARS and MERS, the lag time in the development of therapeutics is likely to take months to years. These facts call for the development of broad-spectrum anti-coronavirus drugs targeting a conserved target site. This review will systematically describe potential broad-spectrum coronavirus fusion inhibitors, including antibodies, protease inhibitors, and peptide fusion inhibitors, along with a discussion of their advantages and disadvantages.