Preclinical pharmacological evaluation of the fatty acid amide hydrolase inhibitor BIA 10‐2474

Abstract

Background and Purpose: In 2016, one person died and four others had mild-tosevere neurological symptoms during a phase I trial of the fatty acid amide hydrolase (FAAH) inhibitor BIA 10-2474.Experimental Approach: Pharmacodynamic and pharmacokinetic studies were performed with BIA 10-2474, PF-04457845 and JNJ-42165279 using mice, rats and human FAAH expressed in COS cells. Selectivity was evaluated by activity-based protein profiling (APBB) in rats. BIA 10-2474 effect in stroke-prone spontaneously hypertensive rats (SHRSP) was investigated.Key Results: BIA 10-2474 was 10-fold less potent than PF-04457845 in inhibiting human FAAH in situ but inhibited mouse brain and liver FAAH with ED 50 values of 13.5 and 6.2 μgÁkg −1 , respectively. Plasma and brain BIA 10-2474 levels were consistent with in situ potency and neither BIA 10-2474 nor its metabolites accumulated following repeat administration. FAAH and α/β-hydrolase domain containing 6 were the primary targets of BIA 10-2474 and, at higher exposure levels, ABHD11, PNPLA6, PLA2G15, PLA2G6 and androgen-induced protein 1. At 100 mgÁkg −1 for 28 days, the level of several lipid species containing arachidonic acid increased. Daily treatment of SHRSP with BIA 10-2474 did not affect mortality rate or increased the incidence of haemorrhage or oedema in surviving animals.Conclusions and Implications: BIA 10-2474 potently inhibits FAAH in vivo, similarly to PF-04457845 and interacts with a number of lipid processing enzymes, some previously identified in human cells as off-targets particularly at high levels of exposure.These interactions occurred at doses used in toxicology studies, but the implication of these off-targets in the clinical trial accident remains unclear.Abbreviations: 2-AG, 2-arachidonoylglycerol; AA, arachidonic acid; ABHD6, α/β-hydrolase domain containing 6; ABPP, activity-based protein profiling; AEA, anandamide; AIG1, androgeninduced protein 1; BCRP, breast cancer resistance protein; CES, carboxyl esterase; CYP, cytochrome P450; DAG, diacylglycerol; FAAH, fatty acid amide hydrolase; LIPE, lipase E; MATE, multidrug and toxin extrusion; MDR, multidrug resistance; OAT, organic anion transporter; OCT, organic cation transporter; OEA, oleoylethanolamide; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PEA, palmitoylethanolamide; P-gp, P-glycoprotein; PLA2G15, PLA 2 Group 15; PLA2G6, PLA 2 Group 6; PNPLA6, patatin-like phospholipase domain containing 6; SHRSP, Spontaneously hypertensive rats stroke prone; TAMRA-FP, tetramethylrhodamine-fluorophosphonate.

Non-clinical toxicology evaluation of BIA 10-2474

“…In the rat brain, BIA 10-2445 was the most prevalent metabolite after administration of 10 mg/kg PO reaching about 20% of the parent C max . BIA 10-2631 and BIA 10-2639 were also detected but at less than 10% of parent (Bonifacio et al 2020). Following 5 days of 10 mg/kg PO the detected levels were broadly similar to those seen after acute administration, with no evidence of accumulation of any of the measured substances (Bonifacio et al 2020).…”

“…BIA 10-2631 and BIA 10-2639 were also detected but at less than 10% of parent (Bonifacio et al 2020). Following 5 days of 10 mg/kg PO the detected levels were broadly similar to those seen after acute administration, with no evidence of accumulation of any of the measured substances (Bonifacio et al 2020). In rat plasma, levels of BIA 10-2445 and BIA 10-2583 were analyzed after 1, 97, and 85 days of the 26-week toxicology study at 10, 30, or 90 mg/ kg PO of BIA 10-2474, producing AUC levels which did not exceed 3% and 1% respectively of the parent (Hayes, Hardisty, Harris, Okazaki, Weber 2020).…”

“…There were also increases in cholesterol (rats and mice) and phospholipids, both seen at low doses from 10 mg/kg. It is possible that these changes are related to the reported interaction of BIA 10-2474 with lipid processing enzymes (van Esbroeck et al 2017;Bonifacio, Loureiro, et al 2018;Bonifacio et al 2020).…”

“…The pharmacology of BIA 10-2474 has been extensively studied against both human and animal targets (van Esbroeck et al 2017;Bonifacio et al 2020). These studies have demonstrated that BIA 10-2474 is a potent inhibitor of FAAH in situ and in vivo.…”

“…Their conclusion was that the accident was likely to have been caused by an unknown off-target effect of BIA 10-2474 (CSST 2016). Despite several studies and the identification of some off-target interactions with other serine hydrolase enzymes (van Esbroeck et al 2017;Bonifacio et al 2020), the mechanism responsible for the toxicity remains unproven.…”