Polymorphisms of CYP2D6 gene and gefitinib-induced hepatotoxicity

Genetic Variants in the ABCB1 and ABCG2 Gene Drug Transporters Involved in Gefitinib-Associated Adverse Reaction: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to verify the association between the genetic variants of adenosine triphosphate (ATP)-binding cassette subfamily B member 1 (ABCB1) and ATP-binding cassette subfamily G member 2 (ABCG2) genes and the presence and severity of gefitinib-associated adverse reactions. We systematically searched PubMed, Virtual Health Library/Bireme, Scopus, Embase, and Web of Science databases for relevant studies published up to February 2024. In total, five studies were included in the review. Additionally, eight genetic variants related to ABCB1 (rs1045642, rs1128503, rs2032582, and rs1025836) and ABCG2 (rs2231142, rs2231137, rs2622604, and 15622C>T) genes were analyzed. Meta-analysis showed a significant association between the ABCB1 gene rs1045642 TT genotype and presence of diarrhea (OR = 5.41, 95% CI: 1.38-21.14, I2 = 0%), the ABCB1 gene rs1128503 TT genotype and CT + TT group and the presence of skin rash (OR = 4.37, 95% CI: 1.51-12.61, I2 = 0% and OR = 6.99, 95%CI: 1.61-30.30, I2= 0%, respectively), and the ABCG2 gene rs2231142 CC genotype and presence of diarrhea (OR = 3.87, 95% CI: 1.53-9.84, I2 = 39%). No ABCB1 or ABCG2 genes were positively associated with the severity of adverse reactions associated with gefitinib. In conclusion, this study showed that ABCB1 and ABCG2 variants are likely to exhibit clinical implications in predicting the presence of adverse reactions to gefitinib.

Amelioration of the therapeutic potential of gefitinib against breast cancer using nanostructured lipid carriers

Aim: This study aimed to improve the delivery and therapeutic potential of gefitinib (GTB) against breast cancer by preparing GTB-loaded, nanostructured lipid carriers (GTB-NLCs). Materials & methods: Box-Behnken design was used for optimization and GTB was loaded into NLCs using ultrasonication. The GTB-NLCs were characterized using in vitro, ex vivo and in vivo studies. The anticancer efficacy of GTB-NLCs was evaluated using 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide cytotoxicity and flow cytometry on MCF-7 breast cancer cell lines. Results: Optimized GTB-NLCs were successfully characterized and demonstrated improved internalization and enhanced cytotoxicity compared with plain GTB. Gut permeation studies showed enhanced intestinal permeability, and pharmacokinetic analysis revealed 2.6-fold improvement in GTB oral bioavailability. Conclusion: GTB-NLCs effectively enhanced the therapeutic potential of GTB against breast cancer.

Hepatotoxicity of Small Molecule Protein Kinase Inhibitors for Cancer

Small molecule protein kinase inhibitors (PKIs) have become an effective strategy for cancer patients. However, hepatotoxicity is a major safety concern of these drugs, since the majority are reported to increase transaminases, and few of them (Idelalisib, Lapatinib, Pazopanib, Pexidartinib, Ponatinib, Regorafenib, Sunitinib) have a boxed label warning. The exact rate of PKI-induced hepatoxicity is not well defined due to the fact that the majority of data arise from pre-registration or registration trials on fairly selected patients, and the post-marketing data are often based only on the most severe described cases, whereas most real practice studies do not include drug-related hepatotoxicity as an end point. Although these side effects are usually reversible by dose adjustment or therapy suspension, or by switching to an alternative PKI, and fatality is uncommon, all patients undergoing PKIs should be carefully pre-evaluated and monitored. The management of this complication requires an individually tailored reappraisal of the risk/benefit ratio, especially in patients who are responding to therapy. This review reports the currently available data on the risk and management of hepatotoxicity of all the approved PKIs.

Study on the hepatotoxicity and potential mechanism of gefitinib based on CYP450 in mice and AML12 cells

OBJECTIVES

Gefitinib is mainly used for the treatment of non-small-cell lung cancer. Hepatotoxicity is one of the main side effects of gefitinib, and seriously affects the treatment process of the disease. However, the hepatotoxicity mechanism of gefitinib remains unclear.

METHODS

The hepatotoxicity of different doses of gefitinib was investigated in mice and AML-12 cells, and the possible correlation of hepatotoxicity with CYP450 was analysed.

KEY FINDINGS

The toxic effects of gefitinib were confirmed by the increased liver index, decreased body weight and survival rate, injured liver function and histopathology followed 16 days of oral administration. Gefitinib (400 mg/kg) upregulated the hepatic mRNA expression of CYP1A1 and downregulated the CYP2D9 and CYP2D10 in mice. Furthermore, we verified that gefitinib produced cytotoxicity on AML-12 cells in a dose and time-dependent manner, and confirmed that gefitinib (20 μM) induced cell apoptosis, upregulated mRNA expression of CYP1A1 and downregulated CYP2D9 and CYP2D10. Pearson correlation analysis also showed that the hepatotoxicity of gefitinib was positively correlated with CYP1A1 and negatively correlated with CYP2D9 and CYP2D10.

CONCLUSIONS

Our results suggested that the hepatotoxicity gefitinib may be associated with CYP1A1, CYP2D9 and CYP2D10. These findings will contribute to a better understanding of the mechanism of gefitinib hepatotoxicity.

Association of genetic polymorphisms of CYP3A4 and CYP2D6 with gefitinib-induced toxicities

Dermatological, gastrointestinal and hepatic toxicities are the most common adverse events associated with gefitinib use. Gefitinib is metabolized by cytochrome P450. Inconsistent associations of single nucleotide genetic polymorphisms of CYP450 and gefitinib-induced adverse effects were reported. We aim to investigate the association between CYP450 genetic polymorphism and the development of gefitinib-associated adverse events. A retrospective cohort study of Chinese patients with metastatic nonsmall cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations who received first-line gefitinib treatment was conducted. Single nucleotide polymorphisms (SNPs) of CYP2D6, CYP3A4 and CYP3A5 were assayed using a multiplex SNP microarray. Risks of development of gefitinib-induced toxicities associated with different SNPs were determined. Among the 152 patients treated with gefitinib, 52 (34.2%) had gefitinib-induced hepatotoxicity, 113 (74.3%) had cutaneous reactions and 53 (34.9%) had gastrointestinal adverse effects. CYP2D6*41 CT, CYP2D6*10 AA and CYP3A4*1/*1G TT genotypes were significantly associated with hepatic, cutaneous and gastrointestinal adverse effects [odds ratio (OR) 3.773; (95% confidence interval {CI},1.046-13.610; P = 0.043), 3.368 (95% CI, 1.000-11.345; P = 0.050) and 20.000 (95% CI, 2.381-167.965; P = 0.006), respectively]. CYP2D6*41 CT, CYP2D6*10 AA and CYP3A4*1/*1G TT genotypes may be associated with increased risks of gefitinib-induced toxicities in the liver, skin and gastrointestinal tract.

Bioactivation and Reactivity Research Advances - 2021 year in review

This year's review on bioactivation and reactivity began as a part of the annual review on biotransformation and bioactivation led by Cyrus Khojasteh (Khojasteh et al., 2021, 2020, 2019, 2018, 2017; Baillie et al., 2016). Increased contributions from experts in the field led to the development of a stand alone edition for the first time this year focused specifically on bioactivation and reactivity. Our objective for this review is to highlight and share articles which we deem influential and significant regarding the development of covalent inhibitors, mechanisms of reactive metabolite formation, enzyme inactivation, and drug safety. Based on the selected articles, we created two sections: (1) reactivity and enzyme inactivation, and (2) bioactivation mechanisms and safety (Table 1). Several biotransformation experts have contributed to this effort from academic and industry settings.

FOXO3 mutation predicting gefitinib-induced hepatotoxicity in NSCLC patients through regulation of autophagy

Hepatotoxicity is a common side effect for patients treated with gefitinib, but the related pathogenesis is unclear and lacks effective predictor and management strategies. A multi-omics approach integrating pharmacometabolomics, pharmacokinetics and pharmacogenomics was employed in non-small cell lung cancer patients to identify the effective predictor for gefitinib-induced hepatotoxicity and explore optional therapy substitution. Here, we found that patients with rs4946935 AA, located in Forkhead Box O3 (FOXO3) which is a well-known autophagic regulator, had a higher risk of hepatotoxicity than those with the GA or GG variant (OR = 18.020, 95%CI = 2.473 to 459.1784, P = 0.018) in a gefitinib-concentration dependent pattern. Furthermore, functional experiments identified that rs4946935_A impaired the expression of FOXO3 by inhibiting the promotor activity, increasing the threshold of autophagy initiation and inhibiting the autophagic activity which contributed to gefitinib-induced liver injury. In contrast, erlotinib-induced liver injury was independent on the variant and expression levels of FOXO3. This study reveals that FOXO3 mutation, leading to autophagic imbalance, plays important role in gefitinib-induced hepatotoxicity, especially for patients with high concentration of gefitinib. In conclusion, FOXO3 mutation is an effective predictor and erlotinib might be an appropriately and well-tolerated treatment option for patients carrying rs4946935 AA.

Clinically actionable genotypes for anticancer prescribing among >1500 patients with pharmacogenomic testing

BACKGROUND

In recent years, there has been increasing evidence supporting the role of germline pharmacogenomic factors predicting toxicity for anticancer therapies. Although somatic genomic data are used frequently in oncology care planning, germline pharmacogenomic testing is not. This study hypothesizes that comprehensive germline pharmacogenomic profiling could have high relevance for cancer care.

METHODS

Between January 2011 and August 2020, patients at the University of Chicago Medical Center were genotyped across custom germline pharmacogenomic panels for reasons unrelated to cancer care. Actionable anticancer pharmacogenomic gene/drug interactions identified by the FDA were defined including: CYP2C9 (erdafitinib), CYP2D6 (gefitinib), DPYD (5-fluorouracil and capecitabine), TPMT (thioguanine and mercaptopurine), and UGT1A1 (belinostat, irinotecan, nilotinib, pazopanib, and sacituzumab-govitecan hziy). The primary objective was to determine the frequency of individuals with actionable or high-risk genotypes across these 5 key pharmacogenes, thus potentially impacting prescribing for at least 1 of these 11 commonly prescribed anticancer therapies.

RESULTS

Data from a total of 1586 genotyped individuals were analyzed. The oncology pharmacogene with the highest prevalence of high-risk, actionable genotypes was UGT1A1, impacting 17% of genotyped individuals. Actionable TPMT and DPYD genotypes were found in 9% and 4% of patients, respectively. Overall, nearly one-third of patients genotyped across all 5 genes (161/525, 31%) had at least one actionable genotype.

CONCLUSIONS

These data suggest that germline pharmacogenomic testing for 5 key pharmacogenes could identify a substantial proportion of patients at risk with standard dosing, an estimated impact similar to that of somatic genomic profiling.

LAY SUMMARY

Differences in our genes may explain why some drugs work safely in certain individuals but can cause side effects in others. Pharmacogenomics is the study of how genetic variations affect an individual's response to medications. In this study, an evaluation was done for important genetic variations that can affect the tolerability of anticancer therapy. By analyzing the genetic results of >1500 patients, it was found that nearly one-third have genetic variations that could alter recommendations of what drug, or how much of, an anticancer therapy they should be given. Performing pharmacogenomic testing before prescribing could help to guide personalized oncology care.

Crizotinib and Sunitinib Induce Hepatotoxicity and Mitochondrial Apoptosis in L02 Cells via ROS and Nrf2 Signaling Pathway

Considerable attention has been raised on crizotinib- and sunitinib-induced hepatotoxicity, but the underlying mechanisms need further examination. In addition, limited therapeutic strategies exist to reduce the liver damage caused by crizotinib and sunitinib. This study investigated the mechanisms of crizotinib- and sunitinib-induced hepatotoxicity and the potential mitigation through ROS and Nrf2 signaling. Firstly, crizotinib and sunitinib reduced cell viability in human liver cells (L02 cells) and triggered dramatic liver injury in mice. Subsequently, we found that crizotinib and sunitinib activated the oxidative stress response (decreased level of GPx and SOD, and increased MDA content) in vivo. Crizotinib and sunitinib also stimulated hepatocyte mitochondrial apoptosis and necrosis in L02 cells in a dose-dependent manner. In vivo studies further confirmed that crizotinib and sunitinib decreased mitochondrial membrane potential and activated apoptosis-associated proteins (cleaved-PARP, cleaved caspase3, cytochrome c, Bcl2 and Bax). Furthermore, mechanistic investigations demonstrated that crizotinib and sunitinib accumulated ROS and inhibited Nrf2 signaling, and that ROS scavenger NAC and Nrf2 agonist tBHQ alleviated the extent of cell damage and the mitochondrial apoptosis during crizotinib- and sunitinib-induced hepatotoxicity in L02 cells. Collectively, these findings indicated that NAC and tBHQ play the crucial roles in crizotinib- and sunitinib-induced mitochondrial apoptosis via the regulation of oxidative stress.

Hepatotoxicity of FDA-approved small molecule kinase inhibitors

Introduction: Given their importance in cellular processes and association with numerous diseases, protein kinases have emerged as promising targets for drugs. The FDA has approved greater than fifty small molecule kinase inhibitors (SMKIs) since 2001. Nevertheless, severe hepatotoxicity and related fatal cases have grown as a potential challenge in the advancement of these drugs, and the identification and diagnosis of drug-induced liver injury (DILI) are thorny problems for clinicians.Areas covered: This article summarizes the progression and analyzes the significant features in the study of SMKI hepatotoxicity, including clinical observations and investigations of the underlying mechanisms.Expert opinion: The understanding of SMKI-associated hepatotoxicity relies on the development of preclinical models and improvement of clinical assessment. With a full understanding of the role of inflammation in DILI and the mediating role of cytokines in inflammation, cytokines are promising candidates as sensitive and specific biomarkers for DILI. The emergence of three-dimensional spheroid models demonstrates potential use in providing clinically relevant data and predicting hepatotoxicity of SMKIs.

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

•

A total of 346 patients were enrolled in this study.

•

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

•

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

•

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.

An investigation into possible interactions among four vascular epidermal growth factor receptor-tyrosine kinase inhibitors with gefitinib

The objective of present work is to evaluate possible interactions among four clinically-used vascular epidermal growth factor receptor (VEGFR)-tyrosine kinase inhibitors (TKIs), including apatinib, cabozantinib, sorafenib, and sunitinib, with epidermal growth factor receptor (EGFR)-TKI gefitinib. This may advance knowledge regarding possible dual-target suppression strategies for advanced NSCLC, including VEGFR-TKI plus EGFR-TKI. The in vitro metabolism study demonstrated that apatinib inhibited the formation of metabolite M537194 with moderate effect, and inhibited another metabolite formation of M523595 with strong effect, in both human and rat liver microsomes. Sorafenib, cabozantinib, and sunitinib had no significant inhibitory effect on gefitinib metabolism. The results of the in vivo pharmacokinetics study were consistent with the in vitro metabolism study: the AUC_0-t, AUC_0-∞ and C_max of gefitinib increased significantly when co-administered with apatinib by 26.8, 28.7, and 19.8%, respectively. Cabozantinib, sorafenib, and sunitinib exhibited no effect on gefitinib pharmacokinetics. Molecular docking was applied to investigate the binding mode between TKIs and CYP2D6. The docking results illustrated that binding characteristics of apatinib and gefitinib with CYP2D6 were similar, which accounts for competitive mechanism of apatinib-inhibited gefitinib metabolism. In summary, apatinib inhibited the metabolism of gefitinib in vitro and in vivo that were mediated by CYP2D6 and CYP3A4. In addition, cabozantinib, sorafenib, and sunitinib expressed no interaction with gefitinib. The results of the present study may provide a basis and valuable information for the development of treatment strategies.

Multikinase inhibitor-induced liver injury in patients with cancer: A review for clinicians

BACKGROUND

Multikinase inhibitors (MKI) are targeted molecular agents that have revolutionized cancer management. However, there is a paucity of data concerning MKI-related liver injury risk and clinical guidelines for the management of liver toxicity in patients receiving MKI for cancer are scarce.

DESIGN

We conducted a PubMed search of articles in English published from January 2000 to December 2018 related to hepatotoxicity of the 29 FDA-approved MKIs at doses used in clinical practice. The search terms were the international non-proprietary name of each agent cross-referenced with «hepatotoxicity», «hepatitis», «hepatic adverse event», or «liver failure», and «phase II clinical trial», «phase III clinical trial», or «case report».

RESULTS

Following this search, 140 relevant studies and 99 case reports were considered. Although asymptomatic elevation of aminotransferase levels has been frequently observed in MKI clinical trials, clinically significant hepatotoxicity is a rare event. In most cases, the interval between treatment initiation and the onset of liver injury is between one week and two months. Liver toxicity is often hepatocellular and less frequently mixed. Life-threatening MKI-induced hepatic injury has been described, involving fulminant liver failure or death. Starting from existing data, a description of MKI-related liver events, grading of hepatotoxicity risk, and recommendations for management are also given for various MKI molecules.

CONCLUSION

All MKIs can potentially cause liver injury, which is sometimes irreversible. As there is still no strategy available to prevent MKI-related hepatotoxicity, early detection remains crucial. The surveillance of liver function during treatment may help in the early detection of hepatotoxicity. Furthermore, the exclusion of potential causes of hepatic injury is essential to avoid unnecessary MKI withdrawal.

Pharmacogenomics to Predict Tumor Therapy Response: A Focus on ATP-Binding Cassette Transporters and Cytochromes P450

Pharmacogenomics is an evolving tool of precision medicine. Recently, due to the introduction of next-generation sequencing and projects generating "Big Data", a plethora of new genetic variants in pharmacogenes have been discovered. Cancer resistance is a major complication often preventing successful anticancer treatments. Pharmacogenomics of both somatic mutations in tumor cells and germline variants may help optimize targeted treatments and improve the response to conventional oncological therapy. In addition, integrative approaches combining copy number variations and long noncoding RNA profiling with germline and somatic variations seem to be a promising approach as well. In pharmacology, expression and enzyme activity are traditionally the more studied aspects of ATP-binding cassette transporters and cytochromes P450. In this review, we briefly introduce the field of pharmacogenomics and the advancements driven by next-generation sequencing and outline the possible roles of genetic variation in the two large pharmacogene superfamilies. Although the evidence needs further substantiation, somatic and copy number variants as well as rare variants and common polymorphisms in these genes could all affect response to cancer therapy. Regulation by long noncoding RNAs has also been shown to play a role. However, in all these areas, more comprehensive studies on larger sets of patients are needed.

Pharmacogenomics of anticancer drugs: Personalising the choice and dose to manage drug response

The field of pharmacogenomics has made great strides in oncology over the last 20 years and indeed a significant number of pre-emptive genetic tests are now routinely undertaken prior to anticancer drug administration. Many of these gene-drug interactions are the fruits of candidate gene and genome-wide association studies, which have largely focused on common genetic variants (allele frequency>1%). Examples where there is clinical utility include genotyping or phenotyping for G6PD to prevent rasburicase-induced RBC haemolysis, and TPMT to prevent thiopurine-induced bone marrow suppression. Other associations such as CYP2D6 status in determining the efficacy of tamoxifen are more controversial because of contradictory evidence from different sources, which has led to variability in the implementation of testing. As genomic technology becomes ever cheaper and more accessible, we must look to the additional data our genome can provide to explain interindividual variability in anticancer drug response. Clearly genes do not act on their own and it is therefore important to investigate genetic factors in conjunction with clinical factors, interacting concomitant drug therapies and other factors such as the microbiome, which can all affect drug disposition. Taking account of all of these factors, in conjunction with the somatic genome, is more likely to provide better predictive accuracy in determining anticancer drug response, both efficacy and safety. This review summarises the existing knowledge related to the pharmacogenomics of anticancer drugs and discusses areas of opportunity for further advances in personalisation of therapy in order to improve both drug safety and efficacy.

Safety of EGFR-TKIs for EGFR mutation-positive non-small cell lung cancer

Introduction: Lung cancer is the most prevalent malignant tumors worldwide. Over the past decade, the emergence of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) has ushered in a new era of lung cancer treatment. Therefore, clinical trials investigating the efficacy and safety of these drugs are important.Areas covered: This review provides an overview on the safety of three classes of EGFR-TKIs and discusses the adverse events (AEs) and reactions reported in the literature.Expert opinion: EGFR-TKIs significantly improve progression-free survival and overall survival in non-small cell lung cancer (NSCLC) patients with an activating mutation of EGFR. However, EGFR-TKIs also block the EGFR-regulating pathways in the skin and gastrointestinal tract and cause AEs, including diarrhea, liver toxicity, skin disease, stomatitis, interstitial lung disease, and ocular toxicity, which have detrimental effects on quality of life and drug compliance. Clinicians should understand how to prevent and control these adverse reactions, which can often be achieved by dose reduction, discontinuation of treatment, or switching to another drug.

Long-term safety of icotinib in patients with non-small cell lung cancer: a retrospective, real-world study

Background

Lung cancer is a global health problem with a high mortality, and the development of target therapy has led to a revolution in the treatment of lung cancer in recent years. Favorable efficacy and safety of icotinib have been demonstrated in patients with non-small cell lung cancer (NSCLC). Currently, minimal data are available to describe the long-term safety of icotinib in NSCLC patients.

Methods

We reviewed the safety data from 1,321 advanced NSCLC patients who were treated with icotinib. The primary endpoint was the long-term safety, defined as any adverse drug reactions (ADRs) occurred after 6 months of icotinib administration.

Results

Fewer ADRs were noticed over 6 month administration of icotinib than within 6 months in overall population (24.3% vs. 65.4%), and elderly patients (23.6% vs. 66.9%). The majority of ADRs were grade 1–2 in severity over 6 month exposure of icotinib in overall population as well as elderly patients. In overall population, the most common ADRs of icotinib during long-term use were rash (16.4%) and diarrhea (5.3%), while the incidences were 31.8% and 13.2% in the induction period, respectively. In elderly population, the most common ADRs of icotinib during long-term use were rash (15.7%) and diarrhea (4.7%), while the incidences were 27.8% and 14.9% in the induction period, respectively, and more inching was observed in the induction period as compared with long term use (6.3% vs. 0.3%).

Conclusions

There was an evidence of decreased frequency of icotinib-induced ADRs over time, and icotinib was well-tolerated in elderly NSCLC patients.

Polymorphisms of NF-κB pathway genes influence adverse drug reactions of gefitinib in NSCLC patients

Gefitinib is a widely used targeted therapeutic drug in East Asian non-small cell lung cancer (NSCLC) patients. This research retrospectively investigated the relationship between the polymorphisms of genes involved in NF-κB pathways and gefitinib-related Adverse Drug Reactions (ADRs). From 2011 to 2016, 109 NSCLC patients were enrolled in this study. Thirty-two SNPs of 15 genes were genotyped with a Sequenom MassARRAY system. We collected 34 paired RNA samples before and after gefitinib administration for the detection of whole blood RNA expression of genes in NF-κB pathways (NFKBIA, NFKB1, NFKB2, RELA, RELB, and TNFAIP3). IKBKB rs2272733 (CC vs non-CC: OR = 0.256, 95% CI 0.087-0.753, P = 0.013) and IKBKE rs12142086 (CC vs non-CC: OR = 3.640, 95% CI 1.320-10.039, P = 0.013) were significantly associated with gefitinib-induced skin toxicity. IKBKE rs2151222 was associated with diarrhea with the odds ratio of non-TT vs TT as 0.162 (non-TT vs TT: 95% CI 0.034-0.775, P = 0.023). Furthermore, RELA rs11227247 was a predictor for hepatic toxicity (GG vs non-GG: OR = 0.212, 95% CI 0.062-0.726, P = 0.013). None of the gene expression levels after drug administration were determined to be significant predictors for adverse drug reactions by a logistics regression analysis. Polymorphisms of IKBKB, IKBKE, and RELA are potential biomarkers for predicting gefitinib-related ADRs. Further studies are needed to understand the underlying mechanisms for diagnostic and prophylactic therapy applications.

Efficacy of gefitinib at reduced dose in EGFR mutant non-small cell lung carcinoma

As a first-generation epidermal growth factor receptor-tyrosine kinase inhibitor, gefitinib was approved by the US Food and Drug Administration for treatment of advanced non-small cell carcinoma with sensitizing EGFR mutations. Gefitinib is known to have adverse effects, which may necessitate dose reduction or even change to alternative preparation of epidermal growth factor receptor-tyrosine kinase inhibitor. There has been concern on dose reduction resulting in reduced dose gefitinib, especially on its efficacy. This was a retrospective single-center cohort study conducted in Queen Mary Hospital in Hong Kong that included 159 Chinese patients with advanced adenocarcinoma of lung that carried sensitizing EGFR mutations and had received gefitinib as first-line treatment. Patients who had reduced dose at 250 mg alternate day were compared with those who were able to maintain on standard dose of gefitinib at 250 mg daily. The primary end-point was progression-free survival. Among the 159 patients, 17 (10.7 %) of them were on reduced dose gefitinib, 14 among the 17 patients (82.4%) because of hepatotoxicity, and 3 (17.6%) because of cutaneous side effects. Patients on reduced dose and standard dose of gefitinib have comparable median progression-free survival. Hazard ratio was 1.121 (95% confidence interval = 0. 655-1.917, P-value = 0.678) for the reduced dose group and 3.385 for the standard dose group (95% confidence interval = 2.181-5.255) respectively (P-value < 0.001). Dose reduction in gefitinib to 250 mg alternate day in response to adverse effects was not associated with inferior outcome for patients on first-line gefitinib for advanced non-small cell carcinoma. Dose reduction is a feasible option for patients who have significant adverse effects with gefitinib.

A metabolomic perspective of pazopanib-induced acute hepatotoxicity in mice

To elucidate the metabolism of pazopanib, a metabolomics approach was performed based on ultra-performance liquid chromatography coupled with electrospray ionization quadrupole mass spectrometry. A total of 22 pazopanib metabolites were identified in vitro and in vivo. Among these metabolites, 17 were novel, including several cysteine adducts and aldehyde derivatives. By screening using recombinant CYPs, CYP3A4 and CYP1A2 were found to be the main forms involved in the pazopanib hydroxylation. Formation of a cysteine conjugate (M3), an aldehyde derivative (M15) and two N-oxide metabolites (M18 and M20) from pazopanib could induce the oxidative stress that may be responsible in part for pazopanib-induced hepatotoxicity. Morphological observation of the liver suggested that pazopanib (300 mg/kg) could cause liver injury. The aspartate transaminase and alanine aminotransferase in serum significantly increased after pazopanib (150, 300 mg/kg) treatment; this liver injury could be partially reversed by the broad-spectrum CYP inhibitor 1-aminobenzotriazole (ABT). Metabolomics analysis revealed that pazopanib could significantly change the levels of L-carnitine, proline and lysophosphatidylcholine 18:1 in liver. Additionally, drug metabolism-related gene expression analysis revealed that hepatic Cyp2d22 and Abcb1a (P-gp) mRNAs were significantly lowered by pazopanib treatment. In conclusion, this study provides a global view of pazopanib metabolism and clues to its influence on hepatic function.

Impact of single nucleotide polymorphisms on the efficacy and toxicity of EGFR tyrosine kinase inhibitors in advanced non-small cell lung cancer patients

EGFR tyrosine kinase inhibitors (EGFR-TKIs) are the treatment of choice for advanced-stage (IIIB-IV) NSCLC patients with mutations in EGFR. However, EGFR-TKIs clinical outcomes vary from person to person and these inter-individual differences may be due to genetic factors such as single nucleotide polymorphisms (SNPs). SNPs in genes involved in EGFR-TKIs pharmacodynamics, metabolism and mechanism of action have been demonstrated to be associated with response, survival and toxicity in advanced NSCLC patients treated with EGFR-TKIs. Here we review the influence of gene polymorphisms in the EGFR pathway on clinical outcome and toxicity to EGFR-TKIs in advanced NSCLC patients. The EGFR-216 polymorphism has reported a strong association between response and/or survival to EGFR-TKIs in Caucasian population. Similarly, the effect of EGFR-CA repeats polymorphisms on survival of advanced NSCLC patients treated with EGFR-TKIs have been confirmed both in Caucasian and Asian population. The influence on toxicity of the -216, -191, CA repeats, Arg497Lys and Asp994Asp polymorphisms in EGFR have also been confirmed. Polymorphisms in AKT (rs1130214 and rs1130233) and SMAD3 (rs6494633, rs11071938 and rs11632964) have been associated with survival in advanced NSCLC patients treated with EGFR-TKIs. However, data come from a limited number of studies and need to be confirmed. Finally, polymorphisms in genes coding proteins of the membrane transporters and cytochrome P450 enzymes have been less extensively investigated. There are few studies with small samples, which complicated the generalization of their role in EGFR-TKIs treatment.

Targeting EGFR in Lung Cancer: Current Standards and Developments

Lung cancer is the second most common malignant tumor and the leading cause of cancer death. Epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) is a distinct subtype of lung cancer comprising approximately 15-40% of non-squamous tumors. The development of first- and second-generation EGFR tyrosine kinase inhibitors (TKIs) has been a significant step forward in the treatment of patients with EGFR-mutant tumors, and over the last few years has been the therapy of choice in the initial management of patients with activating mutations in EGFR, with some differences in efficacy and toxicity profile. Up to 50% of patients treated with first- and second-generation TKIs develop an EGFR exon 20 T790M mutation at the time of progression. In this context, osimertinib has shown a great benefit in terms of progression-free survival (PFS) in the second-line setting, including central nervous system metastasis control. The FLAURA trial, which compared osimertinib to first-generation inhibitors as first-line therapy, showed a clear PFS advantage for osimertinib and a trend towards an increased overall survival (OS) assessed by investigator review. Although T790M mutation is the most common mechanism of resistance to first- and second-generation EGFR TKIs, other EGFR-dependent and -independent mechanisms have been described, such as HER2 and MET amplifications or BRAF and MEK mutations. Some mechanisms of resistance to osimertinib and other third-generation TKIs have also been described. Several fourth-generation TKIs, targeted drug combinations and immunotherapy strategies are under investigation to overcome resistance to EGFR TKIs in order to improve EGFR-mutant NSCLC patient outcomes.

Factors affecting time to reach and recover from gefitinib-induced hepatotoxicity

Gefitinib is an oral tyrosine kinase inhibitor targeting the epidermal growth factor receptor (EGFR) for non-small-cell lung cancer with EGFR mutations. Although a few studies have analyzed the causes of gefitinib-induced hepatotoxicity, research focusing on the time intervals before and after hepatotoxicity has yet to be reported. Therefore, this study investigated two types of factors: the time to reach gefitinib-induced hepatotoxicity and the time for recovery. From January 2013 to December 2014, a retrospective study was carried out on 473 non-small-cell lung cancer patients who were treated with gefitinib. The following data were collected: sex, age, body weight, height, body surface area, underlying disease, Eastern Cooperative Oncology Group Performance Status, smoking history, gefitinib dose, EGFR mutation, and concomitant drugs. Multivariate models showed that patients with mutations in exon 19 had around two-fold higher hepatotoxicity (≥grade 2). Use of CYP3A4 inhibitors and smoking shortened time to hepatotoxicity ∼5-2-fold, respectively, whereas mutations in exon 21 prolonged time to hepatotoxicity by about 2.4-fold. Termination of gefitinib therapy showed 3.8-fold faster recovery. Our study showed that the concomitant use of CYP3A4 inhibitors, smoking, and exon 21 affected the time to reach gefitinib-induced hepatotoxicity. Among the factors examined in this study including hepatotonic use and gefitinib termination, only cessation of gefitinib therapy significantly accelerated recovery.

Effects of Concomitant Medication Use on Gefitinib-Induced Hepatotoxicity

Gefitinib is a drug used for the treatment of non-small cell lung cancer (NSCLC) patients. Severe hepatotoxicity was observed, but only a few cases have been reported on the hepatotoxicity of gefitinib. This study aimed to investigate the association between gefitinib-induced hepatotoxicity and various factors including concomitant medications in lung cancer patients. From January 2013 to December 2014, a retrospective study was performed with NSCLC patients who were treated with gefitinib. Associations between hepatotoxicity and various factors including concomitant drugs were analyzed. Based on multivariate models, it was found that H2 antagonists, proton pump inhibitors (PPIs), and H2 antagonists or PPIs increased hepatotoxicity by about 1.5- to 1.7-fold. Patients younger than 65 years showed 1.6 times higher hepatotoxicity than those older than 65 years. Patients with EGFR mutations had around 2-fold higher hepatotoxicity, and the percentage of incidence of hepatotoxicity because of exon 19 deletion was 32.7%. Our study showed that anti-acid-secreting agents in addition to age younger than 65 years and EGFR mutation were associated with gefitinib-induced hepatotoxicity. Thus, close monitoring of liver function is recommended, especially for patients using anti-acid-secreting agents.

Functional characterization of wild-type and 24 CYP2D6 allelic variants on gefitinib metabolism in vitro

Background

Cytochrome P450 2D6 (CYP2D6), a member of the CYP450 enzyme super family, is a polymorphic enzyme that metabolizes ~25% of therapeutic drugs. CYP2D6 exhibits significant genetic polymorphisms which might cause adverse effects and therapeutic failures of some drugs.

Objective

The purpose of this study was to evaluate the catalytic activities of 22 novel CYP2D6 alleles (CYP2D6*87, *88, *89, *90, *91, *92, *93, *94, *95, *96, *97, *98, R25Q, F164L, E215K, F219S, V327M, D336N, V342M, R344Q, R440C, R497C) on the metabolism of gefitinib in vitro.

Methods and results

CYP2D6 variants were incubated with 1–100 μM gefitinib for 60 min at 37°C and the reaction was terminated by cooling to −80°C immediately. Gefitinib and its metabolite O-desmethyl gefitinib were analyzed by an ultra-performance liquid chromatography-tandem mass spectrometry system. Compared to CYP2D6.1, most CYP2D6 variants exhibited significantly decreased relative clearance values (from 3.11% to 79.35%), whereas CYP2D6.92 and CYP2D6.96 displayed no detectable enzyme activity. Only CYP2D6.94 exhibited a markedly increased intrinsic clearance value, and eight variants (CYP2D6.88, CYP2D6.89, CYP2D6.91, CYP2D6.97, V342M, R344Q, F219S, and F164L) showed no significant difference. In addition, 23 CYP2D6 allelic isoforms exhibited substrate inhibition trend toward gefitinib.

Conclusion

As the first study of all the aforementioned alleles for gefitinib metabolism, these comprehensive data may help in the clinical assessment of the metabolism of gefitinib, and may also offer a reference for personalized treatment with gefitinib in clinical settings.

Whole exome sequencing detects variants of genes that mediate response to anticancer drugs

Certain interindividual differences affecting the efficacy of drug treatment and adverse drug reactions are caused by genetic variants, and their phenotypic effects differ among ethnic groups. In this study, we used whole exome sequencing (WES) systematically to identify germline mutations that influence the activities of drug-metabolizing enzymes, as well as that of a transporter. We analyzed DNA isolated from blood samples from 2,042 Japanese patients with diverse cancers. We identified sequence variants of CYP2B6 (rs3745274), CYP2C9 (rs1057910), CYP2C19 (rs4986893), CYP2C19 (rs4244285), TPMT (rs1142345), NAT2 (rs1799930), NAT2 (rs1799931), UGT1A1 (rs4148323), COMT (rs4680), ABCB1 (rs1045642), and CDA (rs60369023). Wider application of WES will help to determine the effects of mutations on the activities of proteins encoded by drug response genes, and the information gained will accelerate the development of personalized therapies for patients with cancer. Moreover, this knowledge may provide clues for preventing cancer before the onset of symptoms.

Safe and successful treatment with afatinib in three postoperative non-small cell lung cancer patients with recurrences following gefitinib/erlotinib-induced hepatotoxicity

BACKGROUND

Gefitinib and/or erlotinib-induced hepatotoxicity sometimes lead to treatment failure in EGFR mutation-positive patients with non-small cell lung cancer (NSCLC), even though the therapeutic effect is evident.

CASES

Here, we report three postoperative NSCLC patients with recurrences who experienced severe hepatotoxicity while receiving gefitinib and/or erlotinib treatment but could be safely switched to afatinib treatment.

CONCLUSION

Afatinib could be a well-tolerated EGFR-TKI that could be chosen for its relatively low hepatotoxicity, which is attributable to its having a different metabolic mechanism compared to other EGFR-TKIs.

Effects of 31 FDA approved small-molecule kinase inhibitors on isolated rat liver mitochondria

The FDA has approved 31 small-molecule kinase inhibitors (KIs) for human use as of November 2016, with six having black box warnings for hepatotoxicity (BBW-H) in product labeling. The precise mechanisms and risk factors for KI-induced hepatotoxicity are poorly understood. Here, the 31 KIs were tested in isolated rat liver mitochondria, an in vitro system recently proposed to be a useful tool to predict drug-induced hepatotoxicity in humans. The KIs were incubated with mitochondria or submitochondrial particles at concentrations ranging from therapeutic maximal blood concentrations (Cmax) levels to 100-fold Cmax levels. Ten endpoints were measured, including oxygen consumption rate, inner membrane potential, cytochrome c release, swelling, reactive oxygen species, and individual respiratory chain complex (I–V) activities. Of the 31 KIs examined only three including sorafenib, regorafenib and pazopanib, all of which are hepatotoxic, caused significant mitochondrial toxicity at concentrations equal to the Cmax, indicating that mitochondrial toxicity likely contributes to the pathogenesis of hepatotoxicity associated with these KIs. At concentrations equal to 100-fold Cmax, 18 KIs were found to be toxic to mitochondria, and among six KIs with BBW-H, mitochondrial injury was induced by regorafenib, lapatinib, idelalisib, and pazopanib, but not ponatinib, or sunitinib. Mitochondrial liability at 100-fold Cmax had a positive predictive power (PPV) of 72% and negative predictive power (NPV) of 33% in predicting human KI hepatotoxicity as defined by product labeling, with the sensitivity and specificity being 62% and 44%, respectively. Similar predictive power was obtained using the criterion of Cmax ≥1.1 µM or daily dose ≥100 mg. Mitochondrial liability at 1–2.5-fold Cmax showed a 100% PPV and specificity, though the NPV and sensitivity were 32% and 14%, respectively. These data provide novel mechanistic insights into KI hepatotoxicity and indicate that mitochondrial toxicity at therapeutic levels can help identify hepatotoxic KIs.

Toxicity profile of epidermal growth factor receptor tyrosine kinase inhibitors in patients with epidermal growth factor receptor gene mutation-positive lung cancer

Recent progress in the research on the molecular biology of lung cancer revealed that the clinical response to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) is associated with the presence of activating EGFR mutations. Three EGFR-TKIs, namely afatinib, erlotinib and gefitinib, are currently available for the treatment of patients with EGFR mutation-positive non-small-cell lung cancer (NSCLC). Due to the dearth of published phase III trials prospectively evaluating the effects of one EGFR-TKI in comparison with another in such patients, the decision-making regarding which agent to recommend to any given patient lies with the treating physician. Given the potential long-term exposure of such patients to EGFR-TKIs, the toxicological properties of these drugs in such patients may differ from those observed in unselected patients. The aim of the present study was to provide an overview of the key adverse events (rash, diarrhea, hepatotoxicity and interstitial lung disease) reported for EGFR-TKIs in clinical trials including patients with advanced NSCLC.

Tyrosine kinase inhibitors: friends or foe in treatment of hepatic fibrosis?

Aberrant activity of tyrosine kinases has been proved to be associated with multiple diseases including fibrotic diseases. Tyrosine kinases inhibitors (TKIs) might be a novel approach to transform the anti-fibrotic treatment. However, both beneficial and adverse effects are observed by researchers when using these TKIs in either preclinical animal models or patients with hepatic fibrosis. Since hepatotoxicity of TKIs is the leading cause for drug withdrawals thus limits its application in anti-fibrosis, not only efficacy but also safety of TKIs should be paid great concerns. It has been observed in a few studies that TKIs could induce relatively high rate of hepatic biochemical markers elevations and even result in liver failure. Fortunately, several strategies have been adopt to handle with the hepatotoxicity. Accumulating evidences suggest that hepatic stellate cells (HSC) play a pivotal role in hepatic fibrogenesis, so it might be a good option to develop selective TKIs specifically targeting HSCs. The present review will briefly summarize the anti-fibrotic mechanism of TKIs, adverse effects of TKIs as well as the novel developed selective delivery of TKIs.

Observation of hepatotoxicity during long-term gefitinib administration in patients with non-small-cell lung cancer

To observe drug-induced hepatotoxicity by long-term gefitinib administration in the treatment of non-small-cell lung cancer. The data of 101 patients with locally advanced or metastatic non-small-cell lung cancer, for which gefitinib had been used orally for 3 months or longer, were retrospectively analyzed. The median duration of gefitinib administration was 14 months (3–60 months). Forty patients (39.6%) developed abnormal hepatic function, among whom 30 patients (29.7%) had grade I hepatotoxicity, six patients (5.9%) had grade II, and four patients (4.0%) had grade III, respectively. The median time from starting gefitinib oral therapy to developing liver dysfunction was 4 months (1–23 months) for the entire cohort. The incidence of hepatotoxicity in the group with a duration of more than 14 months was much higher than that in the group with a duration of less than 14 months (52.0 vs. 27.5%, P=0.012). In thirty-two patients (32/40), abnormal liver function resolved with hepatoprotective treatment, whereas eight patients (8/40) had persistent grade I hepatotoxicity until the last follow-up. Our study showed that long-term gefitinib-induced hepatotoxicity was a common adverse event, especially for the cohort with a duration of longer than 14 months. In most patients with hepatotoxicity, normal liver function was restored and discontinuation of gefitinib was not necessary.

Safety of gefitinib in non-small cell lung cancer treatment

INTRODUCTION

The development of EGFR TKI and the subsequent identification of activating EGFR mutations have dramatically changed how NSCLC is treated. With its recent approval by the US Food and Drug Administration, gefitinib adds to the list of recommended first-line treatments for lung cancer harboring EGFR mutations, which hitherto includes erlotinib and afatinib.

AREAS COVERED

This review summarizes the pharmacological property, clinical efficacy, and safety of gefitinib in major clinical trials and post-marketing studies.

EXPERT OPINION

Gefitinib is a well-tolerated treatment for advanced NSCLC. The most common adverse events are skin reaction and diarrhea, both of which are generally mild, noncumulative, and manageable. Other side effects such as interstitial lung disease and liver toxicity are less common but can be serious. Which EGFR TKI is the preferred first-line treatment is a matter of debate. Gefitinib and erlotinib have comparable efficacy, whereas afatinib may exert superior clinical activity over gefitinib. In terms of the most common toxicities of skin reaction and diarrhea, gefitinib may be the most tolerable of the three. Hence, despite being the earliest EGFR TKI developed, gefitinib continues to be one of the first-line treatments for advanced EGFR-mutated NSCLC, especially when skin and gastrointestinal toxicity is a concern.

Hepatotoxicity of targeted therapy for cancer

INTRODUCTION

Understanding the mechanism of DILI with MTA, and how to avoid and manage these toxicities is essential for minimising inferior cancer treatment outcomes. An organised and comprehensive overview of MTA-associated hepatotoxicity is lacking; this review aims to fill the gap.

AREAS COVERED

A literature review was performed based on published case reports and relevant studies or articles pertaining to the topics on PubMed. Food and Drug Administration drug information documents and search on the US National Library of Medicine LiverTox database was performed for all relevant MTA.

EXPERT OPINION

MTA-associated hepatotoxicity is common but rarely fatal. The pattern of hepatotoxicity is predominantly idiosyncratic. Pharmacogenomics show potential in predicting patients at risk of poorly metabolising or developing immunoallergic responses to MTA, but prospective data is scant. Preventing reactivation of viral hepatitis using anti-viral drugs, and avoidance of drug combinations at high risk of negative interactions are the most readily preventable measures for DILI.

Germline oncopharmacogenetics, a promising field in cancer therapy

Pharmacogenetics (PGx) is the study of the relationship between inter-individual genetic variation and drug responses. Germline variants of genes involved in drug metabolism, drug transport, and drug targets can affect individual response to medications. Cancer therapies are characterized by an intrinsically high toxicity; therefore, the application of pharmacogenetics to cancer patients is a particularly promising method for avoiding the use of inefficacious drugs and preventing the associated adverse effects. However, despite continuing efforts in this field, very few labels include information about germline genetic variants associated with drug responses. DPYD, TPMT, UGT1A1, G6PD, CYP2D6, and HLA are the sole loci for which the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) report specific information. This review highlights the germline PGx variants that have been approved to date for anticancer treatments, and also provides some insights about other germline variants with potential clinical applications. The continuous and rapid evolution of next-generation sequencing applications, together with the development of computational methods, should help to refine the implementation of personalized medicine. One day, clinicians may be able to prescribe the best treatment and the correct drug dosage based on each patient's genotype. This approach would improve treatment efficacy, reduce toxicity, and predict non-responders, thereby decreasing chemotherapy-associated morbidity and improving health benefits.

Relationship Among Gefitinib Exposure, Polymorphisms of Its Metabolizing Enzymes and Transporters, and Side Effects in Japanese Patients With Non-Small-Cell Lung Cancer

INTRODUCTION

The present study investigated the effects of patients' genetic variations in the pharmacokinetics of gefitinib at steady-state. We analyzed 31 Japanese patients with non-small-cell lung cancer (NSCLC) who had been treated with gefitinib. We focused on common polymorphisms within important gefitinib exposure genes, including cytochromes P450 (CYPs) CYP3A4*1G, CYP3A5 (*3), and CYP2D6 (*5 and *10) and ATP-binding cassette (ABC) ABCG2 (421C>A) and ABCB1 (1236C>T, 2677G>T/A, and 3435C>T).

MATERIALS AND METHODS

Fourteen days after beginning 250 mg of gefitinib therapy, when the patients were in steady-state, blood samples were collected just before and 1, 2, 4, 6, 8, 12, and 24 hours after oral gefitinib administration. The plasma concentrations of gefitinib were measured using high-performance liquid chromatography.

RESULTS

The median area under the concentration-time curve from 0 to 24 hours (AUC0-24) and trough plasma concentration (C0) of gefitinib was 10,086 ng · h/mL (range, 3247-24,726 ng · h/mL) and 334 ng/mL (range, 77.9-813 ng/mL), respectively. No significant differences were found in the AUC0-24 or C0 for gefitinib or in the frequency of diarrhea, skin rash or hepatotoxicity among the CYP3A4, CYP3A5, CYP2D6, ABCG2 (421C>A), and ABCB1 (1236C>T, 2677G>T/A, and 3435C>T) genotype groups. However, the AUC0-24 and C0 levels of gefitinib in the patients with diarrhea or hepatotoxicity were significantly greater than in those without (diarrhea: AUC0-24, 14,246 vs. 8918 ng · h/mL, P = .006; C0: 421 vs. 261 ng/mL, P = .002; hepatotoxicity: AUC0-24, 12,967 vs. 8473 ng · h/mL, P = .024; C0: 420 vs. 248 ng/mL, P = .002).

CONCLUSION

The side effects from gefitinib were related to exposure but not genetic polymorphism. Therefore, therapeutic drug monitoring after beginning gefitinib therapy rather than the analysis of polymorphism before initiating therapy might be beneficial.

Afatinib for the treatment of advanced non-small-cell lung cancer

INTRODUCTION

The inhibition of the epidermal growth factor receptor (EGFR) through tyrosine kinase inhibitors (TKIs) represents an effective strategy for EGFR-mutated NSCLC. Afatinib is an irreversible erythroblastosis oncogene B (ErbB) family blocker, able to inhibit the kinase domains of EGFR, HER2 and HER4, and the transphosphorylation of ErbB3 that has recently been approved in the United States for the first-line treatment of EGFR-mutated NSCLC and in Europe and Japan for the treatment of EGFR-mutated TKI-naive patients.

AREAS COVERED

The authors analyzed the pharmacology and the clinical activity of afatinib in NSCLC through a review of the literature. Trials exploring different settings have been reported, including LUX-Lung 3 and LUX-Lung 6, where the drug achieved better outcomes in terms of response rate, progression-free survival and quality of life compared with chemotherapy. The main toxicities of afatinib are gastrointestinal and skin-related adverse events.

EXPERT OPINION

Afatinib showed remarkable efficacy as a first-line treatment in the presence of common EGFR mutations. Afatinib showed some activity in NSCLC with acquired resistance to EGFR TKIs, although, currently, its efficacy after the failure of erlotinib or gefitinib has not been clearly stated. Direct clinical data comparing the activity and tolerability of different inhibitors are still needed.

[Drug induced hepatotoxicity in targeted therapy for lung cancer]

针对驱动基因的靶向药物吉非替尼、厄洛替尼及克唑替尼等在晚期非小细胞肺癌治疗中有着不可替代的地位，然而此类药物给患者带来益处的同时也出现较高的肝脏毒性，现就其肝脏毒性及机制作一综述。

Drug-induced liver injury: what was new in 2013?

INTRODUCTION

The year 2013 continued to highlight numerous aspects of drug-induced liver injury (DILI), with new information communicated via > 1500 publications. New reports of DILI were described and FDA warnings and alerts were issued for a number of products, emphasizing the risks related to hepatotoxicity.

AREAS COVERED

We provide a summary of the year's published reports of new causes of DILI, along with reviews and reports of established hepatotoxins, new and expanded DILI registries and the continuing emphasis placed on genetic and other risk factors. Several new analyses of data generated from the US DILI Network are included.

EXPERT OPINION

The clinical usefulness of pharmacogenetic testing remains to be determined; the number of patients who must be tested is large and the overall risk of DILI is quite small. The role that dose and hepatic metabolism play in causing idiosyncratic DILI was reviewed; daily doses > 50 - 100 mg of medications with high lipophilicity appear to be most predictive of severe DILI, but not in all cases. Restricting access to paracetamol in certain parts of the UK continues to demonstrate a successful reduction in the number of acute liver failure cases and patients listed for liver transplant.