Mechanism of hepatobiliary toxicity of the LPA1 antagonist BMS-986020 developed to treat idiopathic pulmonary fibrosis: Contrasts with BMS-986234 and BMS-986278

In a Phase 2 clinical trial, BMS-986020, a lysophosphatidic acid receptor-1 (LPA1) antagonist, produced hepatobiliary toxicity (increased ALT, AST, and ALP; cholecystitis) and increases in plasma bile acids (BA). Nonclinical investigations conducted to identify a potential mechanism(s) for this toxicity examined BMS-986020 and two LPA1 antagonists structurally distinct from BMS-986020 (BMS-986234 and BMS-986278). BMS-986020 inhibited hepatic BA efflux transporters BSEP (IC50 1.8 μM), MRP3 (IC50 22 μM), and MRP4 (IC50 6.2 μM) and inhibited BA canalicular efflux in human hepatocytes (68% at 10 μM). BMS-986020 inhibited mitochondrial function (basal and maximal respiration, ATP production, and spare capacity) in human hepatocytes and cholangiocytes at ≥10 μM and inhibited phospholipid efflux in human hepatocytes (MDR3 IC50 7.5 μM). A quantitative systems toxicology analysis (DILIsym®), considering pharmacokinetics, BA homeostasis, mitochondrial function, oxidative phosphorylation, and reactive intermediates performed for BMS-986020 recapitulated clinical findings ascribing the effects to BA transporter and mitochondrial electron transport chain inhibition. BMS-986234 and BMS-986278 minimally inhibited hepatic BA transporters (IC50 ≥20 μM) and did not inhibit MDR3 activity (IC50 >100 μM), nor did BMS-986234 inhibit BA efflux (≤50 μM) or mitochondrial function (≤30 μM) (BMS-986278 not evaluated). Multiple mechanisms may be involved in the clinical toxicity observed with BMS-986020. The data indicate that this toxicity was unrelated to LPA1 antagonism since the mechanisms that likely influenced the adverse clinical outcome of BMS-986020 were not observed with equipotent LPA1 antagonists BMS-986234 and BMS-986278. This conclusion is consistent with the lack of hepatobiliary toxicity in nonclinical and clinical safety studies with BMS-986278.