Ana Reis, Alisa Rudnitskaya, Pajaree Chariyavilaskul, Neeraj Dhaun, Vanessa Melville, Jane Goddard, David J. Webb, Andrew R. Pitt, Corinne M. Spickett

Host genetics is a key determinant of COVID-19 outcomes. Previously, the COVID-19 Host Genetics Initiative genome-wide association study used common variants to identify multiple loci associated with COVID-19 outcomes. However, variants with the largest impact on COVID-19 outcomes are expected to be rare in the population. Hence, studying rare variants may provide additional insights into disease susceptibility and pathogenesis, thereby informing therapeutics development. Here, we combined whole-exome and whole-genome sequencing from 21 cohorts across 12 countries and performed rare variant exome-wide burden analyses for COVID-19 outcomes. In an analysis of 5,085 severe disease cases and 571,737 controls, we observed that carrying a rare deleterious variant in the SARS-CoV-2 sensor toll-like receptor TLR7 (on chromosome X) was associated with a 5.3-fold increase in severe disease (95% CI: 2.75–10.05, p = 5.41x10^-7). This association was consistent across sexes. These results further support TLR7 as a genetic determinant of severe disease and suggest that larger studies on rare variants influencing COVID-19 outcomes could provide additional insights.

The aim of this study was to investigate the safety and pharmacokinetic profiles of a newly developed, standardized extract of Centella asiatica (ECa 233) capsule in healthy Thai volunteers. This study was designed as an open-labeled, 2-sequence dosage, single- and repeated-dose study investigated under fasting conditions. Plasma concentrations of the parent compounds and their relative acid metabolites were measured and pharmacokinetic parameters were calculated using noncompartmental analysis. Tolerability was assessed based on physical examinations, monitoring of vital signs, clinical laboratory tests, and any observed adverse events. A key finding of this study was that the pharmacokinetics of ECa 233 in healthy volunteers did not correspond with its pharmacokinetics in animal studies. As indicated in human pharmacokinetic parameters, maximum plasma concentration and area under the curve of the parent compounds (madecassoside and asiaticoside) were very low, while their respective metabolites (madecassic acid and asiatic acid) demonstrated higher values. Based on the pharmacokinetic results observed in the dose comparison, accumulation of active metabolites after repeated dose is highly suggestive. In addition, the asiatic acid profile showed 2-fold increase in C_max and AUC_(0–t) after increasing dose from 250 to 500 mg of ECa 233. Lastly, the safety and tolerability evaluation illustrated that single and multiple doses in both 250 and 500 mg oral administration of ECa 233 were well tolerated, and none of the volunteers discontinued their participation due to adverse effects during the study.

Background: Plasma mycophenolic acid (MPA) concentrations may predict therapeutic response in active lupus nephritis (LN). We determined the efficacy and safety of a concentration-controlled MPA regime in the treatment of severely active LN. Methods: In this prospective study, 19 biopsy-proven class III/IV LN patients were treated with mycophenolate mofetil (MMF) for 48 weeks. The MMF dosage was based on maximal plasma MPA concentration at 1-hour post dose (MPA-C1). All patients had plasma MPA-C1 levels monitored weekly until achieving the targeted level of >13 mg/L. A low-dose steroid protocol was started at 0.5 mg/kg/day and rapidly tapered to 5 mg/day. Therapeutic response was evaluated at week 24 and week 48. MPA area-under-the curve (MPA-AUC_0–12h) was measured at week 12 to verify the optimum dosage. Results: No death or end-stage kidney disease occurred in this study. Seventeen patients (89%) responded to therapy at week 24 with four (21%) patients having complete response. There was no renal relapse at week 48 and four more patients had converted from partial response to complete response. Seventy eight percent of patients achieved the recommended MPA-AUC_0–12h level. No association between plasma MPA concentrations and adverse reactions or infections was found. Conclusions: MPA-C1 may be a practical monitoring of MPA levels in patients with LN. It is convenient to monitor and may facilitate an optimum estimate of MPA exposure.

Background: Ageing and chronic kidney disease (CKD) affect pharmacokinetic (PK) parameters. Since mechanisms are related and remain unclear, cytochrome P450 (CYP) 3A and drug transporter activities were investigated in the elderly with or without CKD and compared to healthy adults using a microdose cocktail.Methods: Healthy young participants (n = 20), healthy elderly participants (n = 16) and elderly patients with CKD (n = 17) received, in study period 1, a single dose of microdose cocktail probe containing 30 µg midazolam, 750 µg dabigatran etexilate, 100 µg atorvastatin, 10 µg pitavastatin, and 50 µg rosuvastatin. After a 14-day wash-out period, healthy young participants continued to study period 2 with the microdose cocktail plus rifampicin. PK parameters including area under the plasma concentration-time curve (AUC), maximum plasma drug concentration (C_max), and half-life were estimated before making pairwise comparisons of geometric mean ratios (GMR) between groups.Results: AUC and C_max GMR (95% confidence interval; CI) of midazolam, a CYP3A probe substrate, were increased 2.30 (1.70–3.09) and 2.90 (2.16–3.88) fold in healthy elderly and elderly patients with CKD, respectively, together with a prolonged half-life. AUC and C_max GMR (95%CI) of atorvastatin, another CYP3A substrate, was increased 2.14 (1.52–3.02) fold in healthy elderly and 4.15 (2.98–5.79) fold in elderly patients with CKD, indicating decreased CYP3A activity related to ageing. Associated AUC changes in the probe drug whose activity could be modified by intestinal P-glycoprotein (P-gp) activity, dabigatran etexilate, were observed in patients with CKD. However, whether the activity of pitavastatin and rosuvastatin is modified by organic anion transporting polypeptide 1B (OATP1B) and of breast cancer resistance protein (BCRP), respectively, in elderly participants with or without CKD was inconclusive.Conclusions: CYP3A activity is reduced in ageing. Intestinal P-gp function might be affected by CKD, but further confirmation appears warranted.Clinical Trial Registration:http://www.thaiclinicaltrials.org/ (TCTR 20180312002 registered on March 07, 2018)