Metabolite identification of a new tyrosine kinase inhibitor, HM781-36B, and a pharmacokinetic study by liquid chromatography/tandem mass spectrometry

Assessments of CYP‑inhibition‑based drug-drug interaction between vonoprazan and poziotinib in vitro and in vivo

CONTEXT

Poziotinib and vonoprazan are two drugs mainly metabolized by CYP3A4. However, the drug-drug interaction between them is unknown.

OBJECTIVE

To study the interaction mechanism and pharmacokinetics of poziotinib on vonoprazan.

MATERIALS AND METHODS

In vitro experiments were performed with rat liver microsomes (RLMs) and the contents of vonoprazan and its metabolite were then determined with UPLC-MS/MS after incubation of RLMs with vonoprazan and gradient concentrations of poziotinib. For the in vivo experiment, rats in the poziotinib treated group were given 5 mg/kg poziotinib by gavage once daily for 7 days, and the control group was only given 0.5% CMC-Na. On Day 8, tail venous blood was collected at different time points after the gavage administration of 10 mg/kg vonoprazan, and used for the quantification of vonoprazan and its metabolite. DAS and SPSS software were used for the pharmacokinetic and statistical analyses.

RESULTS

In vitro experimental data indicated that poziotinib inhibited the metabolism of vonoprazan (IC₅₀ = 10.6 μM) in a mixed model of noncompetitive and uncompetitive inhibition. The inhibitory constant K_i was 0.574 μM and the binding constant αK_i was 2.77 μM. In vivo experiments revealed that the AUC_(0-T) (15.05 vs. 90.95 μg/mL·h) and AUC_(0-∞) (15.05 vs. 91.99 μg/mL·h) of vonoprazan increased significantly with poziotinib pretreatment. The MRT_(0-∞) of vonoprazan increased from 2.29 to 5.51 h, while the CLz/F value decreased from 162.67 to 25.84 L/kg·h after pretreatment with poziotinib.

CONCLUSIONS

Poziotinib could significantly inhibit the metabolism of vonoprazan and more care may be taken when co-administered in the clinic.

Targeting exon 20 insertion mutations in lung cancer

PURPOSE OF REVIEW

The application of tyrosine kinase inhibitor (TKI) has successfully changed the standard of care in epidermal growth factor receptor ( EGFR ) positive non-small cell lung cancer. However, clinical survivals for patients with EGFR exon 20 insertions have failed to improve over the long period and the mutation appeared resistant to EGFR -TKIs. This overview focused on the current treatment strategies, summarized the emerging regimens for patients with EGFR exon 20 insertions, and demonstrated historical challenges and future development.

RECENT FINDING

Current clinical trials suggested that several regimens selectively-targeted EGFR exon 20 insertions presented potent antitumor activity, like mobocertinib and the bispecific anti- EGFR-MET monoclonal antibody amivantamab and were approved by Food and Drug Administration (FDA) in patients progressed beyond first-line treatment. Novel treatments, including DZD9008, CLN-081, revealed modest clinical efficacy as well and clinical trials are underway, which may lead to improvement of survival outcomes.

SUMMARY

Recent clinical evidence indicates that targeted therapies could improve survival benefits to some extent. More efforts on drug development are underway to bring higher response rates both extracranial and intracranial, sustained clinical remission, and better survival benefits.

Amivantamab for the treatment of EGFR exon 20 insertion mutant non-small cell lung cancer

INTRODUCTION

Amivantamab is a monoclonal bispecific anti-EGFR-MET antibody that is the first targeted therapy to be approved for non-small cell lung cancer (NSCLC) patients harboring EGFR exon 20 insertion mutations following progression on chemotherapy, marking a watershed moment for a class of mutations which is generally associated with poor outcomes.

AREAS COVERED

In this article, we outline the drug profile of amivantamab compared with EGFR kinase inhibitors under evaluation in EGFR exon 20 insertion mutant NSCLC. We also review the efficacy and safety data reported from the CHRYSALIS phase I trial, which forms the basis of the recent approval of amivantamab.

EXPERT OPINION

Unlike small molecule EGFR kinase inhibitors, amivantamab has an extracellular mode of action and dual activity against EGFR and MET. It remains to be determined what role MET inhibition plays in toxicity and efficacy and whether dual target inhibition can delay the onset of drug resistance in these cancers. Due to its large molecular size, amivantamab is expected to have poor activity to treat brain metastases. Building on the clinical data so far, future trials that will evaluate combination treatments with brain-penetrant EGFR kinase inhibitors will be critical to move the drug toward a first-line treatment.

Effects of dacomitinib on the pharmacokinetics of poziotinib in vivo and in vitro

CONTEXT

Dacomitinib and poziotinib, irreversible ErbB family blockers, are often used for treatment of non-small cell lung cancer (NSCLC) in the clinic.

OBJECTIVE

This study investigates the effect of dacomitinib on the pharmacokinetics of poziotinib in rats.

MATERIALS AND METHODS

Twelve Sprague-Dawley rats were randomly divided into two groups: the test group (20 mg/kg dacomitinib for 14 consecutive days) and the control group (equal amounts of vehicle). Each group was given an oral dose of 10 mg/kg poziotinib 30 min after administration of dacomitinib or vehicle at the end of the 14 day administration. The concentration of poziotinib in plasma was quantified by UPLC-MS/MS. Both in vitro effects of dacomitinib on poziotinib and the mechanism of the observed inhibition were studied in rat liver microsomes and human liver microsomes.

RESULTS

When orally administered, dacomitinib increased the AUC, T_max and decreased CL of poziotinib (p < 0.05). The IC₅₀ values of M1 in RLM, HLM and CYP3A4 were 11.36, 30.49 and 19.57 µM, respectively. The IC₅₀ values of M2 in RLM, HLM and CYP2D6 were 43.69, 0.34 and 0.11 µM, respectively, and dacomitinib inhibited poziotinib by a mixed way in CYP3A4 and CYP2D6. The results of the in vivo experiments were consistent with those of the in vitro experiments.

CONCLUSIONS

This research demonstrates that a drug-drug interaction between poziotinib and dacomitinib possibly exists when readministered with poziotinib; thus, clinicians should pay attention to the resulting changes in pharmacokinetic parameters and accordingly, adjust the dose of poziotinib in clinical settings.

Breast Cancer Treatments: Updates and New Challenges

Breast cancer (BC) is the most frequent cancer diagnosed in women worldwide. This heterogeneous disease can be classified into four molecular subtypes (luminal A, luminal B, HER2 and triple-negative breast cancer (TNBC)) according to the expression of the estrogen receptor (ER) and the progesterone receptor (PR), and the overexpression of the human epidermal growth factor receptor 2 (HER2). Current BC treatments target these receptors (endocrine and anti-HER2 therapies) as a personalized treatment. Along with chemotherapy and radiotherapy, these therapies can have severe adverse effects and patients can develop resistance to these agents. Moreover, TNBC do not have standardized treatments. Hence, a deeper understanding of the development of new treatments that are more specific and effective in treating each BC subgroup is key. New approaches have recently emerged such as immunotherapy, conjugated antibodies, and targeting other metabolic pathways. This review summarizes current BC treatments and explores the new treatment strategies from a personalized therapy perspective and the resulting challenges.

Late recurrence of lung adenocarcinoma harboring EGFR exon 20 insertion (A763_Y764insFQEA) mutation successfully treated with osimertinib

The EGFR-A763_Y764insFQEA is a unique mutation among EGFR exon 20 insertion mutations in that it is associated with sensitivity to conventional EGFR-tyrosine kinase inhibitors. This mutation, which was not initially covered by conventional reverse transcription polymerase chain reaction (RT-PCR) genotyping method, has only been detected in clinical practice when a next-generation sequencing (NGS)-based cancer panel is implemented. We present the case of a female patient with recurrent lung adenocarcinoma from a lung tumor resected 10 years earlier. Sequential single-gene investigations and the OncomineTM Comprehensive Assay (ver.3) analysis of the recurrent tumor did not reveal any targetable driver mutations. However, the second NGS analysis with the OncoGuideTM NCC oncopanel found the EGFR-A763_Y764insFQEA mutation after tumor progression with carcinomatous lymphangiomatosis and multiple brain metastases. Osimertinib treatment improved her condition immediately. The identical EGFR-A763_Y764insFQEA mutation was detected in the tumor resected 10 years earlier. Based on this common mutation the patient was diagnosed with late recurrence of lung cancer harboring the EGFR-A763_Y764insFQEA mutation. The OncoGuideTM NCC oncopanel covered whole exons of the EGFR gene and was able to detect this mutation. In the present clinical practice, the EGFR-A763_Y764insFQEA mutation is the only treatable mutation among EGFR Ex.20 insertion mutations. We need to understand the gene mutation profile identified by each panel and consider reexamining them for this mutation.

Inhibition and Induction by Poziotinib of Different Rat Cytochrome P450 Enzymes In Vivo and in an In Vitro Cocktail Method

Poziotinib is an orally active, irreversible, pan-HER tyrosine kinase inhibitor used to treat non-small cell lung cancer, breast cancer, and gastric cancer. Poziotinib is currently under clinical investigation, and understanding its drug-drug interactions is extremely important for its future development and clinical application. The cocktail method is most suitable for evaluating the activity of cytochrome P450 enzymes (CYPs). As poziotinib is partially metabolized by CYPs, cocktail probes are used to study the interaction between drugs metabolized by each CYP subtype. Midazolam, bupropion, dextromethorphan, tolbutamide, chlorzoxazone, phenacetin, and their metabolites were used to examine the effects of poziotinib on the activity of cyp1a2, 2b1, 2d1, 2c11, 2e1, and 3a1/2, respectively. The in vitro experiment was carried out by using rat liver microsomes (RLMs), whereas the in vivo experiment involved the comparison of the pharmacokinetic parameters of the probes after co-administration with poziotinib to rats to those of control rats treated with only probes. UPLC-MS/MS was used to detect the probes and their metabolites in rat plasma and rat liver microsomes. The in vitro results revealed that the half-maximal inhibitory concentration values of bupropion and tolbutamide in RLMs were 8.79 and 20.17 μM, respectively, indicating that poziotinib showed varying degrees of inhibition toward cyp2b1 and cyp2c11. Poziotinib was a competitive inhibitor of cyp2b1 and cyp2c11, with Ki values of 16.18 and 17.66 μM, respectively. No time- or concentration-dependence of inhibition by poziotinib was observed toward cyp2b1 and cyp2c11 in RLMs. Additionally, no obvious inhibitory effects were observed on the activity of cyp1a2, cyp2d1, cyp2e1, and cyp3a1/2. In vivo analysis revealed that bupropion, tolbutamide, phenacetin, and chlorzoxazone showed significantly different pharmacokinetic parameters after administration (p < 0.05); there was no significant difference in the pharmacokinetic parameters of dextromethorphan and midazolam. These results show that poziotinib inhibited cyp2b1 and cyp2c11, but induced cyp1a2 and cyp2e1 in rats. Thus, poziotinib inhibited cyp2b1 and cyp2c11 activity in rats, suggesting the possibility of interactions between poziotinib and these CYP substrates and the need for caution when combining them in clinical settings.

Molecular therapeutic targets in non-small cell lung cancer

INTRODUCTION

Several targetable genetic alterations have been identified in non-small cell lung cancers (NSCLC) and drugs targeting these alterations have been approved for the management of advanced NSCLC patients. Driver mutations with emerging clinical trial data include EGFR exon 20 insertion mutations, MET amplification, KRAS G12 C point mutations, RET rearrangements, HER2 amplification and mutations, and FGFR amplification and translocations.

AREAS COVERED

We reviewed English-language articles indexed in Medline and PubMed up to the 1^st of June 2020. In addition, the proceedings of major conferences were reviewed for relevant abstracts. We report data published regarding targeted therapies which are currently approved and for those which are emerging in advanced or metastatic NSCLC.

EXPERT REVIEW

While these drugs have been shown to be efficacious and tolerable, resistance almost always develops. Though next-generation tyrosine kinase inhibitors (TKIs) have been developed, the appropriate sequencing of these drugs is not clear. Evaluating combination therapies to prevent or delay the onset of resistance and understanding mechanisms of resistance are critical areas of emerging research.

Metabolite Profiling in Anticancer Drug Development: A Systematic Review

Drug metabolism is one of the most important pharmacokinetic processes and plays an important role during the stage of drug development. The metabolite profile investigation is important as the metabolites generated could be beneficial for therapy or leading to serious toxicity. This systematic review aims to summarize the research articles relating to the metabolite profile investigation of conventional drugs and herb-derived compounds for cancer chemotherapy, to examine factors influencing metabolite profiling of these drugs/compounds, and to determine the relationship between therapeutic efficacy and toxicity of their metabolites. The literature search was performed through PubMed and ScienceDirect databases up to January 2019. Out of 830 published articles, 78 articles were included in the analysis based on pre-defined inclusion and exclusion criteria. Both phase I and II enzymes metabolize the anticancer agents/herb-derived compounds . The major phase I reactions include oxidation/hydroxylation and hydrolysis, while the major phase II reactions are glucuronidation, methylation, and sulfation. Four main factors were found to influence metabolite formation, including species, gender, and route and dose of drug administration. Some metabolites were identified as active or toxic metabolites. This information is critical for cancer chemotherapy and anticancer drug development.

Targeting EGFR exon 20 insertion mutations in non-small cell lung cancer

Inframe insertions of three or more base pairs in exon 20 of the epidermal growth factor receptor (EGFR) gene were among the first EGFR mutations to be identified as oncogenic drivers in non-small cell lung cancer (NSCLC). However, unlike the classical EGFR L858R point mutation or exon 19 deletions, which represent the majority of EGFR mutations in NSCLC, low frequency EGFR exon 20 insertion mutations are associated with de novo resistance to targeted EGFR inhibitors and correlate with a poor patient prognosis. Here, we review the developments over the last 5 years in which pre-clinical studies, including elucidation of the crystal structure of an EGFR exon 20 insertion mutant kinase, have revealed a unique mechanism of kinase activation and steric conformation that define the lack of response of these EGFR mutations to clinically approved EGFR inhibitors. The recent development of several novel small molecule compounds that selectively inhibit EGFR exon 20 insertions holds promise for future therapeutic options that will be effective for patients with this molecular subtype of NSCLC.

Elucidation of a CGP7930 in vitro metabolite by liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry

RATIONALE

γ-Aminobutyric acid-B (GABAB ) receptors are widely expressed in the nervous system and have been implicated as targets for various neurological and psychiatric disorders. CGP7930 is a positive allosteric modulator of GABAB receptors. It has been demonstrated to reduce drug self-administration and has gained increased research as a potential psychotropic treatment.

METHODS

An in vitro metabolic system with liver microsomes of SD rats has been conducted and evaluated by probe drugs. The predominant in vitro metabolite of CGP7930 was identified and elucidated using liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (LC/ESI-QTOF-MS/MS). Its structure was determined by comparing the characteristic ions of CGP7930 and those of the metabolite, based on the accurate mass measurement by MS and the fragmentation pattern obtained by MS/MS.

RESULTS

We found that the main metabolic pathway of CGP7930 was via a monohydroxylation reaction and the hydroxylation site located at the terminal butyl-carbon. The collision-induced dissociation (CID) fragmentation of the hydroxylated metabolite underwent McLafferty rearrangement and α-cleavage.

CONCLUSIONS

This work provides an understanding of the in vitro metabolism of CGP7930, which is helpful for the further study of the development of potential drug candidates targeting GABAB receptors, for the treatment of depression. The work also demonstrates that the LC/ESI-QTOF-MS/MS method has the advantage of possibly determining the structures of drug metabolites without the use of standards.