IOT-022

Drug combinations have potential for additive or synergistic efficacy in patients with metabolic dysfunction–associated steatohepatitis (MASH).

To assess the safety, efficacy and pharmacokinetics of single or combination treatments in patients with MASH.

In this multicentre, open‐label, platform phase 2 study, patients ( N  = 41) were randomised 1:1 to LYS006 20 mg twice‐daily (bid) monotherapy or LYS006 20 mg bid+tropifexor 200 μg once‐daily (qd) combination therapy for 12 weeks. The primary endpoint was safety; secondary endpoints were efficacy and pharmacokinetics.

Pruritus adverse events (AEs) were reported in 62% of patients in the combination arm. Other AEs were similar between the treatment arms. A greater reduction in alanine aminotransferase (ALT) and liver fat was observed in the combination versus monotherapy arm (ALT: 43% vs. 13% reduction; liver fat: 37% vs. 20% reduction, respectively). No significant impact on biomarkers for liver fibrosis was observed in either treatment arm, but there was an indication for lower plasma exposure to LYS006 upon co‐administration with tropifexor.

LYS006 20 mg bid monotherapy and LYS006 20 mg bid+tropifexor 200 μg qd therapy were well tolerated with the exception of a high frequency of pruritus in the combination arm, consistent with the now known pharmacologic effect of farnesoid X receptor agonists. The greater reductions in ALT and liver fat in the combination arm versus monotherapy arm were similar to those observed with tropifexor as monotherapy in a previously reported phase 2 clinical trial, and clear additional benefit was not observed in combination treatment with LYS006. This study design allowed for rapid screening of potentially high efficacy drug combinations in MASH.

ClinicalTrials.gov identifier: NCT04147195

Drug-induced kidney injury, often resulting from the intracellular accumulation of drugs in renal proximal tubule cells via uptake transporters such as organic anion transporters 1 and 3 (OAT1/3), remains a major obstacle in drug development. Conventional 2-dimensional cultures of human renal proximal tubule epithelial cells (RPTECs) hardly express OAT1/3, limiting their utility for toxicity assessment. In contrast, 3-dimensional (3D) cultures of RPTEC have been shown to markedly upregulate OAT1/3 expression, offering a more physiologically relevant in vitro model for evaluating the toxicity of anionic compounds. In this study, we investigated the mechanism underlying OAT1/3 upregulation in 3D-RPTEC and explored a strategy to mitigate transporter-mediated toxicity. We found that hepatocyte nuclear factor (HNF) 4α expression is also increased in 3D-RPTEC. Motif analysis and cleavage under targets and release using nuclease-quantitative polymerase chain reaction revealed that HNF4α directly binds to the promoters of SLC22A6 and SLC22A8, identifying it as a key transcriptional regulator of OAT1/3 expression. Activation of the farnesoid X receptor (FXR), which represses the binding of HNF4α to promoters through the upregulation of small heterodimer partner (SHP), decreased OAT1/3 expression. Treatment with FXR ligands reduced cellular uptake of OAT1/3 substrates (eg, tenofovir and adefovir) and decreased their cytotoxic effects in 3D-RPTEC. These findings elucidate a transcriptional mechanism by which HNF4α regulates OAT1/3 expression in 3D-RPTEC and demonstrate that FXR agonists can downregulate OAT1/3 expression via the HNF4α-SHP axis. The present study highlights the utility of 3D-RPTEC as a valuable platform for mechanistic studies of transporter regulation. SIGNIFICANCE STATEMENT: This study shows that farnesoid X receptor agonists suppress hepatocyte nuclear factor 4α-mediated OAT1/3 activity in 3-dimensional-cultured renal proximal tubular cells and reduce nucleotide analog-induced toxicity. These findings provide mechanistic insight into transporter regulation and suggest a potential strategy to prevent nephrotoxicity.