A phase 1, randomized study to evaluate safety, tolerability, and pharmacokinetics of GDC-3280, a potential novel anti-fibrotic small molecule, in healthy subjects

Emerging pharmacological options in the treatment of idiopathic pulmonary fibrosis (IPF)

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a progressive-fibrosing lung disease with a median survival of less than 5 years. Currently, two agents, pirfenidone and nintedanib are approved for this disease, and both have been shown to reduce the rate of decline in lung function in patients with IPF. However, both have significant adverse effects and neither completely arrest the decline in lung function.

AREAS COVERED

Thirty experimental agents with unique mechanisms of action that are being evaluated for the treatment of IPF are discussed. These agents work through various mechanisms of action, these include inhibition of transcription nuclear factor k-B on fibroblasts, reduced expression of metalloproteinase 7, the generation of more lysophosphatidic acids, blocking the effects of transforming growth factor ß, and reducing reactive oxygen species as examples of some unique mechanisms of action of these agents.

EXPERT OPINION

New drug development has the potential to expand the treatment options available in the treatment of IPF patients. It is expected that the adverse drug effect profiles will be more favorable than current agents. It is further anticipated that these new agents or combinations of agents will arrest the fibrosis, not just slow the fibrotic process.

CYP1A2 Polymorphism and Drug Co-administration Affect the Blood Levels and Adverse Effects of Pirfenidone

BACKGROUND

Mutations in metabolic enzymes and co-administration of drugs may affect the blood concentration of pirfenidone effective in pulmonary fibrosis. To provide a basis for the precise clinical use of pirfenidone, the authors analyzed the correlation between steady-state pirfenidone trough concentration and adverse drug reactions (ADRs) and examined the impact of CYP1A2*1C (rs2069514) and *1F (rs762551) variants and co-administration on pirfenidone blood concentrations and ADRs.

METHODS

Forty-four patients were enrolled. The blood concentration of pirfenidone was determined using high-performance liquid chromatography. CYP1A2*1C and *1F genotypes were determined using direct SNP sequencing. Additional information related to drug associations was collected to screen factors affecting drug metabolism.

RESULTS

The highest predictive value of ADRs was observed when the steady-state trough concentration of pirfenidone was 3.18 mcg·mL-1 and the area under the receiver operating characteristic curve was 0.701 (P = 0.024). The pirfenidone concentration-to-dose ratio (C/D) in CYP1A2*1F homozygous AA mutants was lower than that in C carriers (CC+AC) (1.28 ± 0.85 vs. 2.03 ± 1.28 mcg·mL-1; P = 0.036). Adverse drug reaction (ADR) incidence in the homozygous AA mutant group (28.0%) was significantly lower than that in the C carriers (CC+AC) (63.2%; P = 0.020), and ADR incidence in the A carriers (AC+AA) was considerably lower than that in the CC group (85.7%; P = 0.039). The C/D value of the combined lansoprazole/rabeprazole group was lower than that of the noncombination group (P < 0.05).

CONCLUSIONS

The ADR incidence was positively correlated with pirfenidone blood concentration. The CYP1A2 (rs762551) AA genotype is associated with lower pirfenidone concentrations and fewer ADRs. Lansoprazole/rabeprazole co-administration reduced pirfenidone concentrations. Randomized controlled trials should further explore personalized dosing of pirfenidone and combination therapies.

Comparative Evaluation of Particle Size Reduction, Salt Formation, and Amorphous Formulation on the Biopharmaceutical Performance of a Weak Base Drug Candidate

Various approaches have been developed to enhance the solubility or dissolution rate for the delivery of poorly water-soluble molecules. In this work, guided by an in silico solubility sensitivity analysis for oral absorption, a comparative assessment of the biopharmaceutical performance of a jet-milled free base, a tosylate salt, and a 50:50 (w/w) amorphous solid dispersion (ASD) with hydroxypropyl methylcellulose acetate succinate (HPMCAS) of a weak base drug candidate, GDC-3280, was conducted. Successful particle size reduction without amorphization or form change was confirmed for the jet-milled free base. The potential of solubility enhancement and desupersaturation risk were identified for tosylate salt and ASD formulation by measurements of tosylate salt solubility product constant (Ksp) and amorphous solubility of GDC-3280. In vitro dissolution testing demonstrated dissolution rate improvement for the jet-milled free base when compared with the unmilled free base and confirmed solubility enhancement followed by desupersaturation for GDC-3280 tosylate salt and ASD formulation. A crystallization inhibitor, hydroxypropyl methylcellulose (HPMC), was found to slow down the desupersaturation of tosylate salt solution, providing general insights for the development of pharmaceutical salts with disproportionation risks. Finally, a pharmacokinetic study in dogs showed that the in vivo exposure increased by 1.7- to 2-fold for the tosylate salt and ASD formulation compared with the jet-milled free base, consistent with the in silico solubility sensitivity analysis for the fraction of drug absorbed. Overall, this work provides insights into the evaluation of multiple formulation approaches for enhancing the biopharmaceutical performance of poorly water-soluble drugs.

A Novel N-Arylpyridone Compound Alleviates the Inflammatory and Fibrotic Reaction of Silicosis by Inhibiting the ASK1-p38 Pathway and Regulating Macrophage Polarization

Silicosis is one of the potentially fatal occupational diseases characterized by respiratory dysfunction, chronic interstitial inflammation, and fibrosis, for which treatment options are limited. Previous studies showed that a novel N-arylpyridone compound named AKEX0011 exhibited anti-inflammatory and anti-fibrotic effects in bleomycin-induced pulmonary fibrosis; however, it is unknown whether it could also be effective against silicosis. Therefore, we sought to investigate the preventive and therapeutic roles of AKEX0011 in a silicosis rodent model and in a silica-stimulated macrophage cell line. In vivo, our results showed that AKEX0011 ameliorated silica-induced imaging lung damages, respiratory dysfunction, reduced the secretion of inflammatory and fibrotic factors (TNF-α, IL-1β, IL-6, TGF-β, IL-4, and IL-10), and the deposition of fibrosis-related proteins (collagen I, fibronectin, and α-SMA), regardless of early or advanced therapy. Specifically, we found that AKEX0011 attenuated silicosis by inhibiting apoptosis, blocking the ASK1-p38 MAPK signaling pathway, and regulating polarization of macrophages. In vitro, AKEX0011 inhibited macrophages from secreting inflammatory cytokines and inhibited apoptosis of macrophages in pre-treated and post-treated models, concurrent with blocking the ASK1-p38 pathway and inhibiting M1 polarization. Collectively, AKEX0011, as a novel N-arylpyridone compound, exerted protective effects for silica-induced pulmonary inflammation and fibrosis both in vivo and in vitro, and hence, it could be a strong drug candidate for the treatment of silicosis.