Discovery of 1-(4-((3-(4-methylpiperazin-1-yl)propyl)amino)benzyl)-5-(trifluoromethyl)pyridin-2(1H)-one, an orally active multi-target agent for the treatment of diabetic nephropathy

A phase I, randomized study to evaluate the safety, tolerability, and pharmacokinetics of mefunidone in healthy subjects

Background

Mefunidone is a novel synthetic compound and is better when compared to pirfenidone for the anti-fibrotic treatment of renal fibrosis in end-stage renal disease. We conducted this first-in-human, phase I clinical trial to determine the safety, tolerability, and pharmacokinetic (PK) (including food effect) profiles of mefunidone administered orally as single and multiple ascending doses in healthy subjects.

Methods

Part A assessed single ascending doses of mefunidone from 25 mg to 800 mg or placebo once daily in the fasting state. Part A also assessed the effect of food on tolerability and PK in the 100 mg cohort. Part B consisted of three treatment groups who received 100 mg, 200 mg, or 400 mg of mefunidone or placebo twice daily (BID, bis in die) on days 1-6 and once in the morning on day 7.

Results

Single oral doses of mefunidone up to 800 mg and multiple doses of mefunidone up to 400 mg BID were all well-tolerated. Mefunidone behaved with ideal dose proportionality within the single-dose range of 50 mg-600 mg and the multiple-dose range of 100 mg BID to 400 mg BID by day 7. High-fat fed conditions led to a delay in Tmax by approximately 1 h and a slight reduction of approximately 20% in Cmax compared to that in fasting conditions, but it did not significantly affect systemic exposure.

Conclusion

Mefunidone exhibited favorable pharmacokinetics and safety profiles. The present study informed and supported further developmental clinical studies of mefunidone.

Clinical Trial Registration

clinicaltrials.gov, identifier CXHL1900206.

Synthesis and structure-activity optimization of hydroxypyridinones against rhabdomyolysis-induced acute kidney injury

The important role of accumulated iron is well recognized in the pathophysiology of rhabdomyolysis-induced acute kidney injury (RM-AKI). Our previous work further confirmed the labile iron triggered iron-dependent ferroptosis thus leading to the renal failure. In view of this, a series of hydroxypyridinones (HOPOs) with excellent iron chelation capability have been designed and synthesized in this study. A lead compound 6k was identified with good ferroptosis inhibition (EC50 = 20 μM) and no obvious cytotoxicity (CC50 > 100 μM), indicating a good therapeutic window (safety index = CC50/EC50 > 5.00). Moreover, intraperitoneal treatment of 6k (10 mg/kg) displayed a superior protective effect than deferiprone (50 mg/kg) in glycerol-induced RM-AKI mice with alleviating kidney dysfunction and pathological injury, decreasing the renal iron level as well as downregulating the mRNA level of ferroptosis associated genes (Acls4 and Ptgs2). Also, 6k exhibited a good in vivo safety profile, even at single high dose up to 1 g/kg without inducing mortality or toxic symptoms. Importantly, 6k could significantly upregulate the protein hypoxia-inducible factor 1α, possibly involving HIF pathway against the ferroptosis. These results collectively highlighted that the strategy of iron chelation and downstream ferroptosis inhibition has a therapeutic potential against RM-AKI.

Synthesis and evaluation of new pirfenidone derivatives as anti-fibrosis agents

Two series of new pirfenidone derivatives, in which phenyl groups or benzyl groups are attached to the nitrogen atom of the pyridin-2(1H)-one moiety were synthesized and evaluated as anti-fibrosis agents. Among them, compound 5d, with a (S)-2-(dimethylamino) propanamido group in the R2 position (series 1) exhibited 10 times the anti-fibrosis activity (IC50: 0.245 mM) of pirfenidone (IC50: 2.75 mM). Compound 9d (series 2) gave an IC50 of 0.035 mM against the human fibroblast cell line HFL1. The mechanism of the optimal compound inhibiting fibrosis was also studied.

Preclinical metabolic characterization of mefunidone, a novel anti-renal fibrosis drug

AIMS

The preclinical evaluation of innovative drugs plays an important role in the new drugs development. As a derivative of pirfenidone (PFD), mefunidone (MFD) has shown better anti-fibrosis and anti-inflammatory activity in both cell lines and animal models. To support the clinical investigations of MFD, the metabolic characterization of MFD was initially evaluated in preclinical models.

MAIN METHODS

The potential metabolites of MFD were analyzed by LC-MS/MS methods. The induction effect of MFD on CYP1A2, CYP2B6, and CYP3A4 was performed in primary human hepatocytes, and the inhibition of CYP enzymes by MFD was also evaluated in human liver microsomes. Finally, the pharmacokinetic profiles of MFD were assessed in SD rats after the rats had received multiple doses (62.5 mg/kg) of MFD.

KEY FINDINGS

MFD was metabolized in three pathways including oxidation, N-demethylation, and hydroxylation. Except for slight inhibition on the activity of CYP2D6, MFD exerted no effect on other CYP enzymes. Moreover, drug accumulation of MFD was not observed in rats after repeated dosing of MFD.

SIGNIFICANCE

MFD was first discovered in preclinical investigations without inducing and inhibiting metabolic enzymes. This work provides some important information about the metabolic characterization of MFD for its further clinical investigations.