Evaluation of the pharmacokinetic effects of itraconazole on alflutinib (AST2818): an open-label, single-center, single-sequence, two-period randomized study in healthy volunteers

Drug-induced enzyme activity inhibition and CYP3A4 genetic polymorphism significantly shape the metabolic characteristics of furmonertinib

This study aimed to elucidate the impact of variations in liver enzyme activity, particularly CYP3A4, on the metabolism of furmonertinib. An in vitro enzyme incubation system was established for furmonertinib using liver microsomes and recombinant CYP3A4 baculosomes, with analytes detected by LC-MS/MS. The pharmacokinetic characteristics of furmonertinib were studied in vivo using Sprague-Dawley rats. It was found that telmisartan significantly inhibited the metabolism of furmonertinib, as demonstrated by a significant increase in the AUC of furmonertinib when co-administered with telmisartan, compared to the furmonertinib-alone group. Mechanistically, it was noncompetitive in rat liver microsomes, while it was mixed competitive and noncompetitive in human liver microsomes and CYP3A4. Considering the genetic polymorphism of CYP3A4, the study further investigated its effect on the kinetics of furmonertinib. The results showed that compared to CYP3A4.1, CYP3A4.29 had significantly increased activity in catalyzing furmonertinib, whereas CYP3A4.7, 9, 10, 12, 13, 14, 18, 23, 33, and 34 showed markedly decreased activity. The inhibitory activity of telmisartan varied in CYP3A4.1 and CYP3A4.18, with IC50 values of 8.56 ± 0.90 μM and 27.48 ± 3.52 μM, respectively. The key loci affecting the inhibitory effect were identified as ARG105, ILE301, ALA370, and LEU373. Collectively, these data would provide a reference for the quantitative application of furmonertinib.

Almonertinib and alflutinib show novel inhibition on rare EGFR S768I mutant cells

PURPOSE

EGFR classical mutations respond well to EGFR tyrosine kinase inhibitors. However, it is uncertain whether currently available EGFR-TKIs are effective against rare EGFR mutations and compound mutations. Herein, the effectiveness of almonertinib and alflutinib, the third-generation tyrosine kinase inhibitors developed in China, on rare EGFR S768I mutations and compound mutations is identified.

METHODS

In this study, using CRISPR method, four EGFR S768I mutation cell lines were constructed, and the sensitivity of EGFR to almonertinib and alflutinib was tested, with positive controls being the 1st (gefitinib), 2nd (afatinib), and 3rd (osimertinib) generation drugs.

RESULTS

The present results indicate that almonertinib and alflutinib can effectively inhibit cell viability and proliferation in rare EGFR S768I mutations through the ERK or AKT pathways in a time-dependent manner, by blocking the cell cycle and inhibiting apoptosis.

CONCLUSIONS

These findings suggest that almonertinib and alflutinib may be potential therapeutic options for non-small cell lung cancer patients with the EGFR S768I mutation.

Phase 1 study to evaluate the effects of rifampin or itraconazole on the pharmacokinetics of limertinib (ASK120067), a novel mutant-selective inhibitor of the epidermal growth factor receptor in healthy Chinese subjects

BACKGROUND

Limertinib is a novel mutant-selective and irreversible inhibitor of the epidermal growth factor receptor under development. A phase 1 open, two-period, single-sequence, self-controlled, two-part study was initiated to characterize the effects of a strong CYP3A4 inducer (rifampin) or inhibitor (itraconazole) on the pharmacokinetics of limertinib.

RESEARCH DESIGN AND METHODS

Twenty-four healthy subjects in each part received a single dose of limertinib alone (160 mg, Part A; 80 mg, Part B) and with multiple doses of rifampin 600 mg once daily (Part A) or itraconazole 200 mg twice daily (Part B).

RESULTS

Coadministration of rifampin decreased exposure (area under the plasma concentration-time curve from time 0 to infinity, AUC0-inf) of limertinib and its active metabolite CCB4580030 by 87.86% (geometric least-squares mean [GLSM] ratio, 12.14%; 90% confidence interval [CI], 9.89-14.92) and 66.82% (GLSM ratio, 33.18%; 90% CI, 27.72-39.72), respectively. Coadministration of itraconazole increased the AUC0-inf of limertinib by 289.8% (GLSM ratio, 389.8%; 90% CI, 334.07-454.82), but decreased that of CCB4580030 by 35.96% (GLSM ratio, 64.04%; 90% CI, 50.78-80.77).

CONCLUSIONS

Our study demonstrates that the concomitant use of limertinib with strong CYP3A inducers or inhibitors is not recommended. A single dose of limertinib, administered with or without rifampin or itraconazole, is generally safe and well tolerated in healthy Chinese subjects.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT05631678.

Involvement of Transporters in Intestinal Drug-Drug Interactions of Oral Targeted Anticancer Drugs Assessed by Changes in Drug Absorption Time

(1) Background: Oral targeted anticancer drugs are victims of presystemic pharmacokinetic drug−drug interactions (DDI). Identification of the nature of these DDIs, i.e., enzyme-based or/and transporter-based, is challenging, since most of these drugs are substrates of intestinal and/or hepatic cytochrome P-450 enzymes and of intestinal membrane transporters. (2) Methods: Variations in mean absorption time (MAT) between DDIs and control period (MAT ratios < 0.77 or >1.30) have been proposed to implicate transporters in DDIs at the intestinal level. This methodology has been applied to a large set of oral targeted anticancer drugs (n = 54, involved in 77 DDI studies), from DDI studies available either in the international literature and/or in publicly accessible FDA files. (3) Results: Significant variations in MAT were evidenced in 33 DDI studies, 12 of which could be explained by modulation of an efflux transporter. In 21 DDI studies, modulation of efflux transporters could not explain the MAT variation, suggesting a possible relevant role of influx transporters in the intestinal absorption. (4) Conclusions: This methodology allows one to suggest the involvement of intestinal transporters in DDIs, and should be used in conjunction with in vitro methodologies to help understanding the origin of DDIs.

Spotlight on Furmonertinib (Alflutinib, AST2818). The Swiss Army Knife (del19, L858R, T790M, Exon 20 Insertions, "uncommon-G719X, S768I, L861Q") Among the Third-Generation EGFR TKIs?

Osimertinib, a third-generation (3G) epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) is now considered the standard of care for the first-line (1L) treatment of advanced EGFR+ NSCLC due to statistically significant improved progression-free survival (PFS) and overall survival (OS) compared with first-generation (1G) treatment from the FLAURA trial. Recently two other 3G EGFR TKIs (aumolertinib and furmonertinib) have been approved in China for treatment of EGFR T790M+ NSCLC. Randomized Phase 3 trials of these two 3G EGFR TKIs have also demonstrated PFS over gefitinib respectively. Among these two Chinese home-grown, 3G EGFR TKIs, furmonertinib seems to most closely resemble osimertinib in terms of dosing regimen, efficacy and adverse events profile. In this article, we reviewed the clinical activity and adverse events of furmonertinib at 80 mg daily (approved dose), potential usage of 160 mg daily for CNS metastasis in EGFR+ NSCLC, and usage of 160 mg or 240 mg daily in EGFR exon20 insertion positive (EGFRex20ins+) NSCLC patients.

Furmonertinib: First Approval

Furmonertinib mesylate (hereafter furmonertinib) [Ivesa^®] is a selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) being developed by Allist Pharmaceuticals for the treatment of patients with EGFR mutation-positive non-small cell lung cancer (NSCLC). In March 2021, furmonertinib received its first approval in China for the treatment of patients with locally advanced or metastatic NSCLC with confirmed EGFR T790M mutation whose disease has progressed during or after EGFR TKI therapy. Furmonertinib (as monotherapy and/or combination therapy) continues to be assessed in phase I/II and phase III trials for NSCLC with EGFR mutation in China, and its clinical development is also underway/planned in China and elsewhere for NSCLC with various EGFR mutations. This article summarizes the milestones in the development of furmonertinib leading to this first approval for EGFR T790M-positive NSCLC.