The analysis of pharmacokinetic and pharmacogenomic impact on gefitinib efficacy in advanced non-small cell lung cancer patients: results from a prospective cohort study

Germline USP36 Mutation Confers Resistance to EGFR-TKIs by Upregulating MLLT3 Expression in Patients with Non-Small Cell Lung Cancer

PURPOSE

Although somatic mutations were explored in depth, limited biomarkers were found to predict the resistance of EGFR tyrosine kinase inhibitors (EGFR-TKI). Previous studies reported N6-methyladenosine (m6A) levels regulated response of EGFR-TKIs; whether the germline variants located in m6A sites affected resistance of EGFR-TKIs is still unknown.

EXPERIMENTAL DESIGN

Patients with non-small cell lung cancer (NSCLC) with EGFR-activating mutation were enrolled to investigate predictors for response of EGFR-TKIs using a genome-wide-variant-m6A analysis. Bioinformatics analysis and series of molecular biology assays were used to uncover the underlying mechanism.

RESULTS

We identified the germline mutation USP36 rs3744797 (C > A, K814N) was associated with survival of patients with NSCLC treated with gefitinib [median progression-free survival (PFS): CC vs. CA, 16.30 vs. 10.50 months, P < 0.0001, HR = 2.45] and erlotinib (median PFS: CC vs. CA, 14.13 vs. 9.47 months, P = 0.041, HR = 2.63). Functionally, the C > A change significantly upregulated USP36 expression by reducing its m6A level. Meanwhile, rs3744797_A (USP36 MUT) was found to facilitate proliferation, migration, and resistance to EGFR-TKIs via upregulating MLLT3 expression in vitro and in vivo. More importantly, MLLT3 and USP36 levels are tightly correlated in patients with NSCLC, which were associated with prognosis of patients. Mechanistically, USP36 MUT stabilized MLLT3 by deubiquitinating MLLT3 in nucleoli and consequently activating its downstream signaling (HIF1α and Snai). Furthermore, inhibition of MLLT3 alleviated USP36 variant-induced EGFR-TKIs resistance in EGFR-mutant NSCLC.

CONCLUSIONS

These findings characterized rs3744797 as an oncogenic variant in mediating EGFR-TKI resistance and tumor aggressiveness through deubiquitinating MLLT3, highlighting the variant as a predictive biomarker for EGFR-TKI response in NSCLC.

Effect of genetic polymorphisms on the pharmacokinetics of gefitinib in healthy Chinese volunteers

Gefitinib is the first-generation drug of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) metabolised by the cytochrome P450 and transported by P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2). In the present study, the pharmacokinetics of gefitinib in healthy Chinese volunteers was investigated and the effect of genetic polymorphisms on its variability was evaluted.Forty-five healthy volunteers were administered a single dose of gefitinib and the blood samples were used for quantifying the concentration of gefitinib and genotyping fifteen single-nucleotide polymorphisms of cytochrome P450 enzymes (CYP3A4, CYP3A5, CYP2D6, CYP2C9 and CYP2C19) and drug transporters (ABCB1 and ABCG2).CYP3A5*3 (rs776746) polymorphism showed a significant influence, with higher gefitinib AUC0-t in carrier of CC genotype than in CT/TT genotype (BH-adjusted p value <0.05). For CYP2C9*3 (rs1057910), significant differences in pharmacokinetics of gefitinib were detected between carriers of AA and AC genotypes, with higher AUC0-t, AUC0-∞ and Cmax in carrier of AC genotype than in AA gen-otype (BH-adjusted p value <0.05). No associations were found between SNPs in CYP3A4, CYP2D6, CYP2C19, ABCB1, ABCG2 and the pharmacokinetics of gefitinib.The SNPs in CYP3A5*3 (rs776746) and CYP2C9*3 (rs1057910) were found to be associated with altered gefitinib pharmacokinetics in healthy Chinese volunteers.

Pharmacokinetics, safety, tolerability, and feasibility of apatinib in combination with gefitinib in stage IIIB-IV EGFR-mutated non-squamous NSCLC: a drug-drug interaction study

PURPOSE

Apatinib combined with gefitinib was proven to benefit advanced EGFR-mutant NSCLC patients in first-line treatment. This study aimed to evaluate the drug-drug interaction of gefitinib and apatinib when coadministered in EGFR-mutated NSCLC patients.

METHODS

In this phase 1b, multi-center, open-label, fixed-sequence study, the drug-drug interaction of gefitinib and apatinib was evaluated when coadministered in EGFR-mutated NSCLC patients. Patients received single-agent apatinib 500 mg QD on days 1-4. Gefitinib 250 mg QD was given on days 5-15 and combined with apatinib 500 mg QD on days 12-15. Serial blood samples were drawn on days 4 and 15. The plasma concentrations and other pharmacokinetics parameters were measured for apatinib with and without gefitinib.

RESULTS

The study enrolled 22 patients and 20 were analyzed for pharmacokinetics. There were no distinct differences in apatinib Cmax and AUC0-τ with versus without gefitinib (geometric LSM ratio, 0.96 [90% CI 0.84-1.10] for Cmax and 1.12 [90% CI 0.96-1.30] for AUC0-τ). Similar PFS and grade of treatment-emergent adverse events (TEAEs) were found between different Cmax and AUC0-τ of apatinib and gefitinib at 500 mg apatinib and 250 mg gefitinib dose levels.

CONCLUSIONS

Apatinib pharmacokinetics parameters were not significantly changed when coadministered with gefitinib. All TEAEs were manageable, and there was no need to change the dose level when combining apatinib and gefitinib (ClinicalTrials.gov identifier: NCT04390984, May 18, 2020).

A Prospective Cohort Study Assessing the Relationship between Plasma Levels of Osimertinib and Treatment Efficacy and Safety

Osimertinib is a standard treatment for patients with EGFR-mutated non-small cell lung carcinoma (NSCLC). We evaluated the relationship between plasma osimertinib concentrations and treatment outcome in patients with NSCLC for this cohort study. The plasma levels of osimertinib and its metabolite AZ5104 were measured a week after the start of treatment (P1). The primary endpoint was to evaluate the correlation between plasma concentration and adverse events (AEs). The correlation with treatment efficacy was one of the secondary endpoints. In patients with CNS metastases, the concentration in the cerebrospinal fluid was also measured. Forty-one patients were enrolled. The frequency of AEs was highest for rash, followed by anorexia and thrombocytopenia. Thirty-eight cases provided measurements for P1. The median plasma concentration of osimertinib was 227 ng/mL, and that of AZ5104 was 16.5 ng/mL. The mean CNS penetration rate of two cases was 3.8%. The P1 in the group with anorexia was significantly higher than that in the group without anorexia (385.0 ng/mL vs. 231.5 ng/mL, p = 0.009). Divided into quartiles by P1 trough level, Q2 + Q3 (164-338 ng/mL) had longer PFS, while Q1 and Q4 had shorter PFS. An appropriate plasma level of osimertinib may avoid some adverse events and induce long PFS. Further large-scale trials are warranted.

FOXM1 Variant Contributes to Gefitinib Resistance via Activating Wnt/β-Catenin Signal Pathway in Patients with Non-Small Cell Lung Cancer

PURPOSE

Although gefitinib prolonged the progression-free survival (PFS) of patients with non-small cell lung cancer (NSCLC), unpredictable resistance limited its clinical efficacy. Novel predictive biomarkers with explicit mechanisms are urgently needed.

EXPERIMENTAL DESIGN

A total of 282 patients with NSCLC with gefitinib treatment were randomly assigned in a 7:3 ratio to exploratory (n = 192) and validation (n = 90) cohorts. The candidate polymorphisms were selected with Haploview4.2 in Hapmap and genotyped by a MassARRAY system, and the feature variables were identified through Randomforest Survival analysis. Tanswell and clonogenic assays, base editing and cell-derived tumor xenograft model were performed to uncover the underlying mechanism.

RESULTS

We found that the germline missense polymorphism rs3742076 (A>G, S628P), located in transactivation domain of FOXM1, was associated with PFS in exploratory (median PFS: GG vs. GA&AA, 9.20 vs. 13.37 months, P = 0.00039, HR = 2.399) and validation (median PFS: GG vs. GA&AA, 8.13 vs. 13.80 months, P = 0.048, HR = 2.628) cohorts. We elucidated that rs3742076_G conferred resistance to gefitinib by increasing protein stability of FOXM1 and facilitating an aggressive phenotype in vitro and in vivo through activating wnt/β-catenin signaling pathway. Meanwhile, FOXM1 level was highly associated with prognosis in patients with EGFR-mutant NSCLC. Mechanistically, FOXM1 rs3742076_G upregulated wnt/β-catenin activity by directly binding to β-catenin in cytoplasm and promoting transcription of β-catenin in nucleus. Remarkably, inhibition of β-catenin markedly reversed rs3742076_G-induced gefitinib resistance and aggressive phenotypes.

CONCLUSIONS

These findings characterized rs3742076_G as a gain-of-function polymorphism in mediating gefitinib resistance and tumor aggressiveness, and highlighted the variant as a predictive biomarker in guiding gefitinib treatment.

Lipidomics reveals that sustained SREBP-1-dependent lipogenesis is a key mediator of gefitinib-acquired resistance in EGFR-mutant lung cancer

Patients with EGFR mutations in non-small cell lung cancer (NSCLC) have been greatly benefited from gefitinib, however, the therapeutic has failed due to the presence of acquired resistance. In this study, we show that gefitinib significantly induces downregulation of Sterol Regulator Element Binding (SREBP1) in therapy-sensitive cells. However, this was not observed in EGFR mutant NSCLC cells with acquired resistance. Lipidomics analysis showed that gefitinib could differently change the proportion of saturated phospholipids and unsaturated phospholipids in gefitinib-sensitive and acquired-resistant cells. Besides, levels of ROS and MDA were increased upon SREBP1 inhibition and even more upon gefitinib treatment. Importantly, inhibition of SREBP1 sensitizes EGFR-mutant therapy-resistant NSCLC to gefitinib both in vitro and in vivo models. These data suggest that sustained de novo lipogenesis through the maintenance of active SRBEP-1 is a key feature of acquired resistance to gefitinib in EGFR mutant lung cancer. Taken together, targeting SREBP1-induced lipogenesis is a promising approach to overcome acquired resistance to gefitinib in EGFR-mutant lung cancer.

The Pharmacokinetics of Gefitinib in a Chinese Cancer Population Group: A Virtual Clinical Trials Population Study

Gefitinib, a selective inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase, is used to treat non-small-cell lung cancer (NSCLC). Lung cancer rates are high in China and are expected to increase over the next decade. CYP 2D6 intermediate metaboliser (IM) phenotypes are more prevalent in the Chinese population compared to Caucasians; the increased risk of drug-drug interactions (DDI) with chemotherapy polypharmacy may lead to different clinical pharmacokinetics outcomes for Chinese patients. This study developed and validated a virtual Chinese cancer population for the pragmatic assessment of gefitinib DDI as a victim drug in Chinese and Caucasian cancer populations. When assessing the impact of 2D6 phenotypes on bupropion mediated CYP 2D6 DDI in Chinese cancer population, we found that AUC increased by at least 60% in extensive metabolizers (EM) and 30% in IM. As a result, fmCYP2D6 was reduced by 15% in IM in the presence of bupropion, translating into > 70% of EM subjects and > 48% of IM subjects with trough concentrations at steady state (Ctrough,ss) below the gefitinib target trough level. The PBPK model predicted that a 500 mg once daily dose in both EM and IM subjects successfully reduced the percent of subjects below the Ctrough,ss. Such changes in Ctrough,ss warrant further investigation and highlight the ability of pharmacokinetic modelling to investigate populations that may be difficult to recruit for traditional clinical studies.

Establishment and application of a predictive model for gefitinib-induced severe rash based on pharmacometabolomic profiling and polymorphisms of transporters in non-small cell lung cancer

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A total of 346 patients were enrolled in this study.

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Severe rash (grade 3&4) did not gain more bonification compare to grade 1&2 rash.

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Gefitinib and its four metabolites were detected in patients’ plasma.

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A specific and sensitive predictive model were established based on pharmacometabolomic profiling and pharmacogenomics approach.

Background

Rash is a well-known predictor of survival for patients with gefitinib therapy with non-small cell lung cancer (NSCLC). However, whether patients with more severe rash obtain the more survival benefits from gefitinib is still unknown, and predicted model for severe rash is needed.

Methods

The relationship between gefitinib-induced rash and progression free survival (PFS) was primarily explored in the retrospective cohort. The association between rash and gefitinib/metabolites concentration and genetic polymorphisms were determined by pharmacometabolomic and pharmacogenomics methods in the exploratory cohort and validated in an external cohort.

Results

The survival for patients with rash was significantly higher than that of patients without rash (p = 0.0002, p = 0.0089), but no difference was found between grade 1/2 or grade 3/4. Only the concentration of gefitinib, but not its metabolites, was found to be associated with severe rash, and the cutoff value of gefitinib was 204.6 ng/mL conducted by ROC curve analysis (AUC=0.685). A predictive model for severe rash was established: gefitinib concentration (OR = 11.523, 95% CI = 2.898-64.016, p = 0.0016), SLC22A8 rs4149179(CT vs CC, OR = 3.156, 95% CI = 0.958–11.164, p = 0.0629), SLC22A1 rs4709400(CG vs CC, OR = 10.267, 95% CI = 2.067–72.465, p = 0.0087; GG vs CC, OR = 5.103, 95% CI = 1.032–33.938, p = 0.061). This model was confirmed in the validation cohort with an excellent predictive ability (AUC = 0.749, 95% CI = 0.710–0.951).

Conclusions

Our finding demonstrated that the incidence, not the severity, of gefitinib-induced rash predicted improved survival, the gefitinib concentration and polymorphisms of SLC22A8 and SLC22A1 were recommended to manage severe rash.

Different efficacy in the non-small cell lung cancer patient with bilateral synchronous lesions treated with neoadjuvant gefitinib therapy: a case report

Gefitinib, the first-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), has become the standard of care for the first-line of therapy for advanced non-small cell lung cancer (NSCLC) with common EGFR mutation. However, the efficacy of preoperative gefitinib therapy in patients with common EGFR mutations remains poorly defined. We describe a NSCLC patient with bilateral synchronous lesions who had a significantly positive response to gefitinib before radical surgical resection. At the time of initial diagnosis, we were unable to confirm whether the two lesions were metastatic or synchronous primary lesions. Accordingly, we performed CT-guided percutaneous left lung biopsy resulting in a diagnosis of lung adenocarcinoma with exon 21 L858R point mutation of EGFR, This diagnosis was followed by preoperative gefitinib therapy for 8 weeks leading to a significant reduction in the lesion in the left lower lobe. Then the left lower lobectomy and mediastinal lymphadenectomy were performed. In addition, 3 months following resection of the left lower lobe tumor the patient underwent a right lower lobe wedge resection. This report indicates that NSCLC patient harboring common EGFR mutation accepting the first-generation EGFR-TKI gefitinib as a neoadjuvant targeted therapy option is safe, feasible, and well-tolerated.