Afatinib versus placebo for patients with advanced, metastatic non-small-cell lung cancer after failure of erlotinib, gefitinib, or both, and one or two lines of chemotherapy (LUX-Lung 1): a phase 2b/3 randomised trial

MEK inhibitors reverse resistance in epidermal growth factor receptor mutation lung cancer cells with acquired resistance to gefitinib

Lung adenocarcinoma cells harboring epidermal growth factor receptor (EGFR) mutations are sensitive to EGFR tyrosine kinase inhibitors (TKIs), including gefitinib. Acquired resistance to EGFR-TKIs develops after prolonged treatments. The study was prompt to explore effective strategies against resistance to EGFR-TKIs. We established gefitinib resistant PC-9 cells which harbor EGFR exon 19 deletion. Known mechanisms for intrinsic or acquired EGFR-TKI resistance, including KRAS mutation, HER2 mutation, EGFR T790M mutation and MET gene amplification, were studied, and we did not observe any known mechanisms for intrinsic or acquired resistance to EGFR-TKIs in the resistant cells. In the parental PC-9 cells, labeled as PC-9/wt, gefitinib completely inhibited EGF-induced phosphorylation of EGFR, AKT and ERK. Gefitinib inhibited EGFR phosphorylation, but was unable to block EGF-induced phosphorylation of ERK in resistant cells, labeled as PC-9/gef cells, including PC-9/gefB4, PC-9/gefE3, and PC-9/gefE7 subclones. We detected NRAS Q61K mutation in the PC-9/gef cells but not the PC-9/wt cells. MEK inhibitors, either AZD6244 or CI1040, inhibited ERK phosphorylation and sensitized gefitinib-induced cytotoxicity in PC-9/gef cells. Whereas MEK inhibitors or gefitinib alone did not activate caspases in PC-9/gef cells, combination of gefitinib and AZD6244 or CI1040 induced apoptosis. Our in vivo studies showed that gefitinib inhibited growth of PC-9/wt xenografts but not PC-9/gef xenografts. Furthermore, combination of a MEK inhibitor and gefitinib inhibited growth of both PC-9/wt xenografts and PC-9/gefB4 xenografts. To conclude, persistent activation of ERK pathway contributes to the acquired gefitinib-resistance. Combined treatment of gefitinib and MEK inhibitors may be therapeutically useful for acquired gefitinib-resistance lung adenocarcinoma cells harboring EGFR mutations.

First- and second-line treatment of non-small-cell lung cancer patients withEGFRmutation-positive tumors

SUMMARY EGFR is a mediator of cell proliferation and is targeted by EGFR tyrosine kinase inhibitors (TKIs) to treat non-small-cell lung cancer (NSCLC). Efficacy of EGFR TKIs (specifically erlotinib and gefitinib) is influenced by mutations in EGFR. We review the evidence for targeted use of EGFR TKIs in the first-line treatment of EGFR mutation-positive NSCLC, considering epidemiology and timing/methodology of diagnosis. First- and second-generation TKIs, and other investigational drugs, also have a role in the second-line treatment of EGFR mutation-positive NSCLC; we discuss this in the context of disease progression and drug resistance. Patients with EGFR mutation-positive tumors should be considered as a separate subpopulation within NSCLC, which is the first step towards individualized treatment of this disease.

Should epidermal growth factor receptor tyrosine kinase inhibitors be considered ideal drugs for the treatment of selected advanced non-small cell lung cancer patients?

An ideal target-based agent for the treatment of cancer patients should fulfil a number of requirements, including the availability of biomarkers to select the target population, superiority over existing treatments and specific advantages in terms of pharmacokinetics and/or metabolism. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, erlotinib and afatinib, have been investigated in the treatment of non-small cell lung cancer (NSCLC), and to date a large amount of clinical data are available. The activity of EGFR-TKIs was initially investigated in unselected patients leading to unsatisfactory results. However, the discovery that response to EGFR-TKIs is associated with the presence of activating EGFR mutations in NSCLC, has led to the design of clinical trials in which patients were selected on the basis of the EGFR mutational status or of clinical and pathological features that are highly associated with the presence of EGFR mutations. In this respect, several phase III randomized trials have demonstrated that first-line EGFR-TKIs, compared to chemotherapy, is associated with longer progression-free survival, higher response rate, better toxicity profile and quality of life in patients carrying EGFR mutations. Although no survival advantage was demonstrated, all the trials suffered of a high post-progression treatment cross-over, which predictably undermined the results. This review will summarize the current evidence that strongly support the hypothesis that gefitinib, erlotinib and afatinib are ideal drugs for NSCLC patients carrying EGFR mutations.

First-line treatment of EGFR-mutant non-small-cell lung cancer: the role of erlotinib and other tyrosine kinase inhibitors

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) were initially established as second- or third-line treatment of advanced non-small-cell lung cancer (NSCLC). Subsequent studies, including IPASS, OPTIMAL, and EURTAC, have demonstrated that these TKIs are effective first-line therapeutic options in patients with tumors harboring activating mutations in the EGFR gene. The TKIs are better tolerated than conventional chemotherapy, with frequent yet mild side effects such as rash and diarrhea, and rarely interstitial lung disease. Because most patients on TKIs develop resistance due to a variety of mechanisms, the use of TKIs in the acquired-resistance setting and in the setting of earlier-staged cancers is being extensively studied. Here we review the major trials leading to the established use of EGFR TKIs in NSCLC, followed by discussion of recently completed and ongoing trials using the next-generation EGFR inhibitor afatinib.

[Advances of molecular subtype and targeted therapy of lung cancer]

The discovery of multiple molecular mechanisms underlying the development, progression, and prognosis of lung cancer, has created new opportunities for targeted therapy. Each subtype is associated with molecular tests that define the subtype and drugs that may have potential therapeutic effect on lung cancer. In 2004, mutations in the epidermal growth factor receptor (epidermal growth factor receptor, EGFR) gene were discovered in non-small cell lung cancers (NSCLC), especially in adenocarcinomas. And they are strongly associated with sensitivity to EGFR-tyrosine kinase inhibitors (EGFR-TKIs). Moreover, in 2007 the existence of the echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene was discovered in NSCLC, and the same as EGFR-TKIs, ALK inhibitors are being found to be highly effective in lung cancers. At present, multiple molecular subtype of lung cancer and relevant targeted drugs are undering study. Here, we review the remarkable progress in molecular subtype of lung cancer and the related targeted therapy.

Mechanisms of Resistance to Epidermal Growth Factor Receptor Inhibitors and Novel Therapeutic Strategies to Overcome Resistance in NSCLC Patients

The epidermal growth factor receptor (EGFR) is a well-characterized oncogene that is frequently activated by somatic kinase domain mutations in non-small cell lung cancer (NSCLC). EGFR TKIs are effective therapies for NSCLC patients whose tumors harbor an EGFR activating mutation. However, EGFR TKI treatment is not curative in patients because of both primary and secondary treatment resistance. Studies over the last decade have identified mechanisms that drive primary and secondary resistance to EGFR TKI treatment. The elucidation of mechanisms of resistance to EGFR TKI treatment provides a basis for the development of therapeutic strategies to overcome resistance and enhance outcomes in NSCLC patients. In this paper, we summarize the mechanisms of resistance to EGFR TKIs that have been identified to date and discusses potential therapeutic strategies to overcome EGFR TKI resistance in NSCLC patients.

Clinical perspectives for irreversible tyrosine kinase inhibitors in cancer

Irreversible inhibitors provide potent and selective inhibition of tyrosine kinase enzymes. Use of such inhibitors has proved promising in overcoming the tumor resistance encountered with reversible tyrosine kinase inhibitors. Irreversible inhibitors inactivate their protein target through covalent interaction with a nucleophilic cysteine residue within the nucleotide binding pocket of the kinase domain. Different irreversible tyrosin kinase inhibitors directed against epidermal growth factor receptor (EGFR), Bruton's tyrosine kinase (BTK), vascular endothelial growth factor receptor (VEGFR) and fibroblast growth factor receptor tyrosine kinase (FGFR) have been developed and some of them have been employed clinically as anticancer agents. This review focuses on recent preclinical and clinical progress with currently available irreversible tyrosine kinase inhibitors. The chemical structures of the candidates, structure-activity relationships, biological activities and results of current clinical investigations are described.

Her-2 targeting in uterine papillary serous carcinoma

► A case of metastatic uterine papillary serous cancer with Her-2 gene amplification. ► Was treated with a Her-2 targeted agent and achieved durable remission. ► Her-2 targeting should be considered alone or in combination with chemotherapy.

Afatinib for patients with lung adenocarcinoma and epidermal growth factor receptor mutations (LUX-Lung 2): a phase 2 trial

BACKGROUND

Afatinib is an irreversible ErbB-family blocker with preclinical activity in non-small-cell lung cancer (NSCLC) with EGFR mutations. We aimed to assess the efficacy of afatinib in patients with lung adenocarcinoma and EGFR mutations.

METHODS

In this phase 2 study, we enrolled patients from 30 centres in Taiwan and the USA with lung adenocarcinoma (stage IIIb with pleural effusion or stage IV) with EGFR mutations, who had no more than one previous chemotherapy regimen for advanced disease, an Eastern Cooperative Oncology Group performance status of 0-2, and no previous treatment with EGFR tyrosine-kinase inhibitors. We tested two afatinib starting doses: 50 mg daily and subsequently 40 mg daily, introduced to establish whether tolerability could be improved with retention of anti-tumour activity. The primary endpoint was the proportion of patients with a confirmed objective response (complete response or partial response), on the basis of Response Evaluation Criteria in Solid Tumors 1.0 (independent review). This study is registered with ClinicalTrials.gov, number NCT00525148.

FINDINGS

129 patients were treated with afatinib, 99 with a starting dose of 50 mg and 30 with a starting dose of 40 mg. 79 (61%) of 129 patients had an objective response (two complete responses, 77 partial responses). 70 (66%) of the 106 patients with the two common activating EGFR mutations (deletion 19 or L858R) had an objective response, as did nine (39%) of 23 patients with less common mutations. Similar proportions of patients had an objective response when analysed by starting dose (18 [60%] of 30 patients at 40 mg vs 61 [62%] of 99 patients at 50 mg). Of the two most common adverse events (diarrhoea and rash or acne), grade 3 events were more common in patients receiving a 50 mg starting dose (22 [22%] of 99 patients for diarrhoea and 28 [28%] of 99 patients for rash or acne) than they were in those receiving a 40 mg starting dose (two [7%] of 30 patients for both diarrhoea and rash or acne); possibly treatment-related serious adverse events were also less common in patients receiving a 40 mg starting dose (two of 30 patients vs 14 of 99 patients). We recorded one possibly drug-related death (interstitial lung disease).

INTERPRETATION

Afatinib shows activity in the treatment of patients with advanced lung adenocarcinoma with EGFR mutations, especially in patients with deletion 19 or L858R mutations. The efficacy of afatinib 40 mg should be compared with chemotherapy or other EGFR tyrosine-kinase inhibitors in EGFR-mutation-positive NSCLC.

FUNDING

Boehringer Ingelheim Inc.