Erlotinib after failure of gefitinib in patients with advanced non-small cell lung cancer previously responding to gefitinib. J Thorac Oncol. 2008;3:912-914. [PMID: 18670311 DOI: 10.1097/jto.0b013e318180275e]

Triple administration of osimertinib followed by chemotherapy for advanced lung adenocarcinoma: A case report

BACKGROUND

Osimertinib is the recommended first-line treatment for adult patients with epidermal growth factor receptor (EGFR) mutation positive advanced or metastatic non-small cell lung cancer (NSCLC). However, primary or acquired resistance to EGFR-tyrosine kinase inhibitors (EGFR-TKIs) seems inevitable, and when drug-resistance occurs during treatment with osimertinib, the standard of care is to discontinue the TKI.

CASE SUMMARY

A 57-year-old female patient with lung adenocarcinoma presented with an irritating cough accompanied by chest distress of one month duration. An enhanced head magnetic resonance imaging scan showed brain metastases. An EGFR mutation (exon 21 L858R) was detected in pleural fluid. The patient was treated with oral osimertinib (80 mg once daily) from January 2018 but developed progressive disease on December 2018. She was then successfully treated with re-challenge and tri-challenge with osimertinib (80 mg once daily) by resensitization chemotherapy twice after the occurrence of drug-resistance to osimertinib, and to date has survived for 31 mo.

CONCLUSION

This case may provide some selective therapeutic options for NSCLC patients with acquired drug-resistance who were previously controlled on osimertinib treatment.

Chemotherapy should be performed in epidermal growth factor receptor mutation-positive lung adenocarcinoma patients who had progressive disease to the first epidermal growth factor receptor-tyrosine kinase inhibitor

After the failure of first-line epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) therapy, some non-small cell lung cancer patients desire to receive switching with another EGFR-TKI (TKI-switching), although cytotoxic chemotherapy has been recommended as second-line therapy. It is unclear who should not receive TKI-switching in these patients. We retrospectively evaluated overall survival (OS) from the initiation of first EGFR-TKI (first-TKI) therapy in advanced lung adenocarcinoma patients with active EGFR mutations (deletion of exon 19 or L858R in exon 21) who received TKI-switching according to the best response of the first-TKI. There was no difference in the OS between patients receiving TKI-switching (n = 35) and patients receiving additional chemotherapy between the first-TKI and second-TKI therapy (n =10) (P = 0.614). Among patients receiving TKI-switching, the OS in cases with progressive disease to the first-TKI (n = 9) was shorter than that in cases with disease control to the first-TKI (n = 26) (12.7 months vs. 49.4 months, P < 0.001). Five of the nine progressive disease cases who received TKI-switching missed an opportunity to receive chemotherapy. Their OS tended to be shorter than that in patients who received chemotherapy during the whole period of anticancer therapy (12.2 months vs. 20.3 months, P = 0.060). The multivariate analysis showed that disease control to the first-TKI therapy (P = 0.005) or the presence of chemotherapy (P = 0.087) decreased the risk of mortality. Chemotherapy should be performed in patients with progressive disease to the first-TKI.

Efficacy and Safety of Gefitinib as Third-line Treatment in NSCLC Patients With Activating EGFR Mutations Treated With First-line Gefitinib Followed by Second-line Chemotherapy: A Single-Arm, Prospective, Multicenter Phase II Study (RE-CHALLENGE, CTONG1304)

Objective:

There is no standard care for advanced non–small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation in the third line. Our study aimed to assess the efficacy and safety of gefitinib as a third-line re-challenge treatment for advanced NSCLC patients with EGFR mutation.

Materials and Methods:

It was a multicenter, open-label, single-arm, phase II study. Stage IIIB/IV NSCLC patients with EGFR exon 19del/L858R mutation, who had benefited from first-line gefitinib treatment followed by second-line chemotherapy, received gefitinib 250 mg/d. The primary objective was disease control rate (DCR) at week 8.

Results:

Predefined DCR was achieved in 69.8% (95% confidence interval, 49.87-74.91) patients and objective response rate was reported in 4.7% (95% confidence interval, 0.78-13.06) patients. Median progression-free survival (PFS) was 4.4 months and overall survival (OS) was 10.3 months. Baseline T790M-negative patients achieved favorable DCR compared with T790M-positive patients (78.1% vs. 45.5%, P=0.0418), significantly longer median PFS (4.7 vs. 2.0 mo, P=0.0009) and median OS (15.2 vs. 7.7 mo, P=0.0132). We observed a negative correlation of PFS (r=−0.4396, P=0.0032), and OS (r=−0.3630, P=0.0167) with mutation abundance of exon 19del/L858R at baseline.

Conclusions:

Re-challenge with gefitinib is effective and could be a choice for third-line patients after the first-line EGFR-TKI treatment and second-line chemotherapy, especially for the T790M-negative patients.

EGFR-TKIs in non-small-cell lung cancer: focus on clinical pharmacology and mechanisms of resistance

The clinical introduction of EGFR-TKIs within the oncologic armamentarium has changed the therapeutic landscape of non-small-cell lung cancer (NSCLC) creating widespread expectations both in patients and clinicians. However, several gaps in current understanding leave open important questions regarding the use of these drugs in clinical practice. For instance, there is uncertainty in regard to which EGFR-TKI should be given first in naive patients with EGFR-driven malignancies since different generations of drugs are available with different pharmacological profiles. Furthermore, acquired drug resistance may limit the therapeutic potential of EGFR-TKIs and the choice of the best treatment strategy after first-line treatment failure is still debated. This review article is aimed at describing the pharmacological properties of EGFR-TKIs and the current treatment options for NSCLC patients who develop acquired resistance. This information might be useful to design new rational and more effective pharmacological strategies in patients with EGFR-mutant NSCLC.

Overcoming ABC transporter-mediated multidrug resistance: The dual role of tyrosine kinase inhibitors as multitargeting agents

Resistance to conventional and target specific antitumor drugs still remains one of the major cause of treatment failure and patience death. This condition often involves ATP-binding cassette (ABC) transporters that, by pumping the drugs outside from cancer cells, attenuate the potency of chemotherapeutics and negatively impact on the fate of anticancer therapy. In recent years, several tyrosine kinase inhibitors (TKIs) (e.g., imatinib, nilotinib, dasatinib, ponatinib, gefitinib, erlotinib, lapatinib, vandetanib, sunitinib, sorafenib) have been reported to interact with ABC transporters (e.g., ABCB1, ABCC1, ABCG2, ABCC10). This finding disclosed a very complex scenario in which TKIs may behave as substrates or inhibitors depending on the expression of specific pumps, drug concentration, affinity for transporters and types of co-administered agents. In this context, in-depth investigation on TKI chemosensitizing functions might provide a strong rationale for combining TKIs and conventional therapeutics in specific malignancies. The reposition of TKIs as antagonists of ABC transporters opens a new way towards anticancer therapy and clinical strategies aimed at counteracting drug resistance. This review will focus on some paradigmatic examples of the complex and not yet fully elucidated interaction between clinical available TKIs (e.g. BCR-ABL, EGFR, VEGFR inhibitors) with the main ABC transporters implicated in multidrug resistance.

Plasma T790M and HGF as potential predictive markers for EGFR-TKI re-challenge

Re-challenge with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) has been suggested to potentially improve survival in certain populations of patients with advanced lung cancer, but predictive markers for the success of EGFR-TKI re-challenge have not been identified. The present study analyzed 16 re-challenges with EGFR-TKI undertaken in 12 patients with lung adenocarcinoma by investigating T790M and hepatocyte growth factor (HGF) in plasma coupled with clinical characteristics. EGFR mutations in plasma DNA were detected using the wild inhibiting PCR and quenched probe system for exon 19 deletions, and T790M and L858R were detected using the mutation-biased PCR and quenched probe system. HGF levels in the plasma were measured by enzyme-linked immunosorbent assay, and the ratio of HGF levels prior to re-challenge to those prior to the previous EGFR-TKI treatment was calculated. Two re-challenges demonstrated partial response, six remained as stable disease and eight had progressive disease (PD). A total of 4 of the 5 patients with a history of T790M positivity based on plasma DNA levels had PD. A total of 7 of the 8 patients who had ≥1.5-fold elevation of HGF prior to re-challenge with EGFR-TKI suffered PD. Elevation of the HGF ratio to ≥1.5 was significantly associated with poor response to EGFR-TKI re-challenge. Having no history of T790M and an HGF ratio <1.5 was significantly associated with a positive response to EGFR-TKI re-challenge. A combination of T790M detection and HGF quantification using plasma is a potentially useful assay system for predicting the effect of EGFR-TKI re-challenge. Future prospective studies are required to confirm the predictive validity of these markers.

Antitumor activity of high-dose pulsatile gefitinib in non-small-cell lung cancer with acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have demonstrated efficacy in the treatment of advanced non-small cell lung cancer (NSCLC). However, their clinical efficacy is limited by acquired resistance. Drug resistance may be mediated by EGFR transduction, and a number of clinical trials have demonstrated that high-dose pulsatile TKIs may be effective at treating patients with acquired resistance, though their underlying mechanisms of action remain unknown. The aim of the present study was to investigate the antitumor activity of high-dose pulsatile gefitinib in NSCLC model cell lines, namely the EGFR-TKI-sensitive cell line PC9, as a control group, and the EGFR-TKI-resistant cell lines H1975 and H1650. The cell lines were administered with different doses of gefitinib and cell viability was measured using an MTT assay. Cell apoptosis and cycling were also determined by flow cytometry and the expression of phospho (p)-EGFR, EGFR, p-AKT and AKT were measured by western blot analysis. It was observed that the apoptotic rate of H1975 cells treated with high-dose pulsatile gefitinib significantly increased, while levels of p-EGFR and p-AKT were decreased. However, there was no significant difference in the apoptotic rate or level of p-AKT in gefitinib-treated H1650 cells, while p-EGFR levels decreased. By contrast, the EGFR-TKI-sensitive cell line PC9 exhibited sensitivity to gefitinib. It was demonstrated that the apoptosis rates were markedly increased when treated with high dose pulsatile gefitinib in PC9 cell line, while a decrease was noted in p-EGFR and p-AKT. These data suggest that high-dose pulsatile gefitinib treatment may overcome acquired resistance in NSCLC, though its efficacy is dependent on the type of drug resistance mutation(s) present. Furthermore, high-dose pulsatile gefitinib may inhibit tumor growth and induce cell apoptosis by blocking the EGFR signaling pathway. Therefore, if the signaling pathways involved in drug resistance are not activated by the EGFR gene, high-dose pulsatile gefitinib may have little efficacy in the treatment of NSCLC.

Local Therapy for Oligoprogressive Disease in Patients With Advanced Stage Non-small-cell Lung Cancer Harboring Epidermal Growth Factor Receptor Mutation

INTRODUCTION

The effect of local therapy (LT) for oligoprogressive epidermal growth factor receptor (EGFR)-mutated non-small-cell lung cancer (NSCLC) has not been well established. Forty-six patients with stage IIIB/IV EGFR-mutated NSCLC were treated by LT and continuing tyrosine kinase inhibitors (TKIs) for oligoprogression. The median overall survival (OS) and progression-free survival (PFS) after LT were 13.0 and 7.0 months, respectively. EGFR mutation type, sites of LT, and time from first progressive disease (PD) to LT were prognostic of OS after LT.

PURPOSE

Patients with advanced stage EGFR-mutated NSCLC treated with EGFR TKIs could experience oligoprogression. This study investigated the benefits of LT and continuation of TKIs for oligoprogression retrospectively.

MATERIALS AND METHODS

Forty-six patients with stage IIIB/IV EGFR-mutated NSCLC on TKIs were treated by LT and continuation of TKIs for oligoprogressive disease. The impact of clinicopathologic variables on survival was explored using Cox regression.

RESULTS

With a median follow-up of 32 months, the 2-year OS was 65.2%, and the estimated OS was 35.0 months. The median OS after LT (LT-OS) was 13.0 months. The median PFS after LT (LT-PFS) was 7.0 months. Univariate analysis showed that stage at initial diagnosis, EGFR mutation type, site of LT, metastatic status at initial TKIs, and time from first PD to LT correlated with LT-OS significantly. Multivariate analysis suggested that EGFR mutation type (P = .001), sites of LT (P = .000), and time from first PD to LT (P = .034) were prognostic of LT-OS. Univariate analysis showed that metastatic status at initial TKIs and time from first PD to LT correlated with LT-PFS significantly. Multivariate analysis suggested that only time from first PD to LT (P = .000) was prognostic of LT-PFS.

CONCLUSION

This study revealed that LTs are feasible and effective for EGFR-mutated NSCLC with oligoprogression. EGFR mutation type, sites of LT, and time from first PD to LT were prognostic factors for LT-OS. Time from first PD to LT was a prognostic factor for LT-PFS.

Predictive Factors for Switched EGFR-TKI Retreatment in Patients with EGFR-Mutant Non-Small Cell Lung Cancer

BACKGROUND

Third-generation tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR-TKIs) have proved efficacious in treating non-small cell lung cancer (NSCLC) patients with acquired resistance resulting from the T790M mutation. However, since almost 50% patients with the acquired resistance do not harbor the T790M mutation, retreatment with first- or second-generation EGFR-TKIs may be a more viable therapeutic option. Here, we identified positive response predictors to retreatment, in patients who switched to a different EGFR-TKI, following initial treatment failure.

METHODS

This study retrospectively reviewed the medical records of 42 NSCLC patients with EGFR mutations, whose cancers had progressed following initial treatment with gefitinib or erlotinib, and who had switched to a different first-generation EGFR-TKI during subsequent retreatment. To identify high response rate predictors in the changed EGFR-TKI retreatment, we analyzed the relationship between clinical and demographic parameters, and positive clinical outcomes, following retreatment with EGFR-TKI.

RESULTS

Overall, 30 (71.4%) patients received gefitinib and 12 (28.6%) patients received erlotinib as their first EGFR-TKI treatment. Following retreatment with a different EGFR-TKI, the overall response and disease control rates were 21.4% and 64.3%, respectively. There was no significant association between their overall responses. The median progression-free survival (PFS) after retreatment was 2.0 months. However, PFS was significantly longer in patients whose time to progression was ≥10 months following initial EGFR-TKI treatment, who had a mutation of exon 19, or whose treatment interval was <90 days.

CONCLUSION

In patients with acquired resistance to initial EGFR-TKI therapy, switched EGFR-TKI retreatment may be a salvage therapy for individuals possessing positive retreatment response predictors.

Epidermal growth factor receptor tyrosine kinase inhibitors with conventional chemotherapy for the treatment of non-small cell lung cancer

We report a Chinese male patient with advanced stage lung squamous cell carcinoma who developed brain metastases after responding to treatment comprising six cycles of conventional chemotherapy with docetaxel and cisplatin. The patient was then treated with oral erlotinib (150 mg/day) and whole-brain radiation therapy followed by four cycles of docetaxel and carboplatin chemotherapy. The patient then received gefitinib (250 mg/day) as a maintenance therapy until the end of the follow-up period. In this patient, progression-free survival, defined as the interval from the initiation of first-line chemotherapy to the cessation of erlotinib due to progressive disease or death from any cause, was 3 months. Overall survival, defined as the interval from the initiation of first-line chemotherapy to death from any cause, was 75 months. Erlotinib was well tolerated in combination with whole-brain radiation therapy and a favorable objective response rate was observed. Furthermore, targeted drug treatment warrants consideration in patients with a negative epidermal growth factor receptor mutation status and male patients with a history of smoking.

Clinical efficacy of erlotinib, a salvage treatment for non-small cell lung cancer patients following gefitinib failure

BACKGROUND/AIMS

The purpose of this study was to identify predictive factors for erlotinib treatment in non-small cell lung cancer (NSCLC) patients following gefitinib failure.

METHODS

Forty-five patients with NSCLC who were treated with erlotinib following gefitinib failure at Seoul National University Hospital between August 2005 and November 2011 were enrolled. Epidermal growth factor receptor (EGFR) mutation status, pathologic findings and other clinical factors, including response to tyrosine kinase inhibitors (TKIs) and progression-free survival (PFS), were evaluated.

RESULTS

Of the 45 patients, 40 patients (88.8%) had adenocarcinoma. The following EGFR mutations were observed: five patients with a deletion of exon 19, six patients with an L858R mutation, three patients with wild-type EGFR, and 31 patients with unknown mutations. The response rate of erlotinib was 4.4%, and stable disease was 42.2%. The median PFS for erlotinib was 2.6 months (95% confidence interval, 1.4 to 3.7). Patients with a PFS ≥ 4 months during previous gefitinib treatment had a significantly longer PFS with erlotinib (3.3 months vs. 1.6 months, respectively; p < 0.01) than patients with PFS < 4 months with gefitinib. According to multivariate analyses, PFS ≥ 4 months for previous gefitinib treatment was significantly associated with prolonged PFS with erlotinib (p = 0.04). However, the response rate of gefitinib and treatment sequence were not associated with prolonged PFS with erlotinib (p = 0.28 and p = 0.67, respectively).

CONCLUSIONS

Following rechallenge with the EGFR TKI erlotinib following gefitinib failure, patients who showed prolonged PFS with gefitinib benefit from erlotinib. However, further prospective studies are needed to confirm these findings.

IL-24 gene transfer sensitizes melanoma cells to erlotinib through modulation of the Apaf-1 and Akt signaling pathways

Interleukin-24 (IL-24) is a novel tumor suppressor/cytokine gene expressed in normal human melanocytes but for which expression is nearly undetectable in metastatic melanoma. Overexpression of the IL-24 protein has been shown to inhibit tumor cell proliferation and induce apoptosis in many melanoma cell lines, and is now considered a tumor suppressor. Erlotinib, a small-molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, has been widely studied for the treatment of human lung cancer and other solid tumors, but the erlotinib-targeted therapy has not been tested in melanoma. The objective of this study is to investigate the potency of erlotinib in suppressing the growth of human melanoma cells and whether IL-24 could enhance the antitumor activity of erlotinib. In cell viability and apoptosis assays, treatment with erlotinib dependently inhibited the growth of different melanoma cell lines and when combined with adenoviral vector-mediated IL-24 gene therapy, a significant increase in cell growth inhibition and apoptosis induction resulted (P<0.05). Immunoblot assay showed that the combination treatment of erlotinib and IL-24 considerably increased the cleavage of caspase-3 and caspase-9 and the expression of Apaf-1 protein in melanoma cells, inducing activation of the Apaf-1-dependent apoptotic pathways. Moreover, this combination treatment markedly inhibited phosphorylation of the EGFR, phosphatidylinositol-3 kinase, and Akt proteins, inactivating the Akt-dependent cell survival signaling pathway. These results show that a combination of IL-24-mediated molecular therapy and EGFR inhibitors such as erlotinib may be a promising treatment strategy for human melanoma and will serve as a basis for guiding the combination treatment designs in future preclinical and clinical trials.

Erlotinib usage after prior treatment with gefitinib in advanced non-small cell lung cancer: A clinical perspective and review of published literature

Erlotinib and gefitinib are among the most widely researched, used and available molecularly targeted therapies for treatment of advanced non-small cell lung cancer (NSCLC). They are both tyrosine kinase inhibitors (TKIs) of the epidermal growth factor receptor (EGFR). In the past decade, there have been reports on clinical benefit from use of erlotinib after gefitinib failure in NSCLC patients. A review of published literature on this focussed topic is provided herein. Pooled analysis of published literature shows that majority of patients were female (60.6%), non-smokers (64.5%), had adenocarcinoma histology (88.3%) and were of East Asian ethnicity (92.3%). Presence of sensitizing EGFR mutation was detected in 48.4% of subjects. Disease control rates with prior gefitinib therapy and with subsequent erlotinib treatment were 79.4% and 45.4% respectively. Based upon our review, the most important predictive factor for clinical benefit from erlotinib identified was previous response to gefitinib. The exact explanations for the potential benefit from erlotinib use in this patient population is still not known and further studies are required to determine the role of molecular mechanisms especially those related to resistance to initial EGFR TKI therapy.

Subsequent treatment choices for patients with acquired resistance to EGFR-TKIs in non-small cell lung cancer: restore after a drug holiday or switch to another EGFR-TKI?

The outcomes of first-generation EGFR-TKIs (Gefitnib and Erlotinib) have shown great advantages over traditional treatment strategies in patients with non-small cell lung cancer (NSCLC), but unfortunately we have to face the situation that most patients still fail to respond in the long term despite initially good control. Up to now, the mechanism of acquired resistance to EGFR-TKIs has not been fully clarified. Herein, we sought to compile the available clinical reports in the hope to better understanding the subsequent treatment choices, particularly on whether restoring after a drug holiday or switching to another EGFR-TKI is the better option after failure of one kind of EGFR-TKI.

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.

Clinical significance of heterogeneity in response to retreatment with epidermal growth factor receptor tyrosine kinase inhibitors in patients with lung cancer acquiring secondary resistance to the drug

BACKGROUND

In patients with lung cancer acquiring resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), an intrapatient heterogeneity in response to retreatment with EGFR-TKIs remains to be elucidated.

PATIENTS AND METHODS

Records were retrospectively reviewed for 68 patients with advanced non-small-cell lung cancer who received second EGFR-TKIs after systemic progression that followed durable response to the first EGFR-TKIs. All tumor lesions identified on radiologic images before second EGFR-TKIs were categorized into organs. Tumor response to EGFR-TKIs was assessed per patient and per organ. Mixed response (MR) was defined as the coexistence of at least 2 responsive and progressive organs.

RESULTS

Tumor lesions were detected in 244 organs. The response rate (RR) and median time to progression (TTP) to second EGFR-TKIs for patients were 26.5% and 11.6 weeks (95% CI, 8.5-14.7 weeks), and the RR and median TTP for organs were 38.8% and 17.3 weeks (95% CI, 14.8-19.8 weeks). Of 35 patients categorized to progressive disease, 22 (62.8%) showed MR. Among organs, the RR was highest for the central nervous system (CNS) and lowest for the liver (CNS vs. others vs. liver: 77.8%, 36.9%, 17.6%; P < .001). Multivariate analysis confirmed the organ type and prior drug sensitivity at the time of stopping first EGFR-TKIs as predictors for the risk of progression to second EGFR-TKIs in organs.

CONCLUSIONS

Intrapatient heterogeneity in response to second EGFR-TKIs is not a rare event. The organ type and prior drug sensitivity at the failure time of first EGFR-TKIs may predict the efficacy of second EGFR-TKIs in individual organs.

Treatment of Non-small Cell Lung Carcinoma after Failure of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor

Since the first description of non-small cell lung cancer (NSCLC) with activating epidermal growth factor receptor (EGFR) mutation as a distinct clinical entity, studies have proved EGFR tyrosine kinase inhibitors (TKIs) as a first choice of treatment. The median response duration of TKIs as a first-line treatment for EGFR mutant tumors ranges from 11 to 14 months. However, acquired resistance to EGFR-TKIs is inevitable due to various mechanisms, such as T790M, c-Met amplification, activation of alternative pathways (IGF-1, HGF, PI3CA, AXL), transformation to mesenchymal cell or small cell features, and tumor heterogeneity. Until development of a successful treatment strategy to overcome such acquired resistance, few options are currently available. Here we provide a summary of the therapeutic options after failure of first line EGFR-TKI treatment for NSCLC.

EGFR tyrosine kinase inhibitors beyond focal progression obtain a prolonged disease control in patients with advanced adenocarcinoma of the lung

INTRODUCTION

Recent data show that EGFR pathway and its inhibition maintain their role after progression of disease during EGFR TKI therapy in NSCLCs. We conducted a retrospective study with the aim of evaluating efficacy and feasibility of prosecution of EGFR TKI therapy beyond focal progression associated to locoregional radiotherapy.

METHODS

We retrospectively analyzed the data of all NSCLC patients treated with EGFR TKIs in our institution from 2004 to 2012. We included in the analysis patients that after a focal disease progression, meant as a single lesion RECIST progression, have been treated with definitive locoregional radiotherapy, associated to continuation of EGFR TKI therapy until further progression.

RESULTS

15 out of 147 patients (10%) satisfied inclusion criteria. The median progression free survival, measured from the date of focal progression until further progression of disease or death by any cause, was 10,9 months (range 3-32 months). The corresponding 6 and 12 months PFS rates were 73% and 33%, respectively.

CONCLUSION

The longer disease control observed in our patients suggests that continuation of EGFR TKI beyond focal progression associated to a locoregional treatment is an efficacious therapeutic strategy.

Gefitinib versus erlotinib as salvage treatment for lung adenocarcinoma patients who benefited from the initial gefitinib: A retrospective study

BACKGROUND

  The optimal strategy was not established for patients who initially responded to gefitinib although re-administration of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) has been proven to be an option. Gefitinib and erlotinib were compared as salvage treatment after gefitinib failure.

METHODS

  Thirty-eight lung adenocarcinoma patients were analyzed retrospectively as they received the second EGFR-TKIs treatment with either gefitinib or erlotinib. All of them had obtained disease control from initial gefitinib. Sixteen patients received gefitinib (G-G group) and 22 patients received erlotinib (G-E group).

RESULTS

  Of all patients, progress free survival (PFS) and overall survival (OS) were three and 12 months, respectively, and the disease controlled rate (DCR) of the second EGFR-TKIs treatment was 52.6%. One patient (6.3%) had partial remission (PR) and 10 (62.5%) had stable disease (SD), in the G-G group, whereas, three (13.6%) had PR and six (27.2%) had SD, in the G-E group. There was no statistical significance observed, although the DCR in the G-G group was higher than that in G-E group (68.8% vs. 40.8%, P= 0.09). Adverse events of both gefitinib and erlotinib were mild and administered. The median PFS and OS in G-G and G-E groups were similar (PFS four vs. three months; OS 22 vs. 12 months). In multivariate analysis, patients with SD in initial gefitinib treatment had significantly longer OS (P= 0.04).

CONCLUSIONS

  Gefitinib as well as erlotinib could be an option for patients who benefited from prior gefitinib treatment. Patients with SD in initial gefitinib obtained a significantly longer OS than those with PR.

T790M and acquired resistance of EGFR TKI: a literature review of clinical reports

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) such as gefitinib and erlotinib are promising therapies for patients with advanced non-small-cell lung cancer (NSCLC). Patients with somatic activating mutations in the EGFR gene have dramatic response initially, but would eventually develop resistance to these TKIs. Subsequent studies found that a secondary mutation in the EGFR gene (T790M mutation) and amplification of the MET proto-oncogene could be the main resistance mechanisms involved. The current review is focused on T790M, which is thought to cause steric hindrance and impair the binding of gefitinib/erlotinib. The T790M is present as a minor allele before TKI therapy and accounts for about half of the acquired resistant cases. Conflicting results were reported for gefitinib-resistant, T790M-acquired patients who had switched to erlotinib treatment, which was proposed to be efficacious. The switch therapy was presumed to work for EGFR wild type patients and previously gefitinib responding patients. MET amplification accounts for about 20% of TKI acquired-resistant patients by a different molecular pathway from T790M; some of these patients will also concurrently have T790M mutation and might still not respond to irreversible TKI. As for the detection of T790M, polymerase chain reaction (PCR), especially mutant-enriched PCR was found to be more sensitive than direct DNA sequencing. In addition, whole genome amplification might also be useful and can be incorporated with future noninvasive method for detecting T790M. A better understanding of the mechanisms leading to TKI resistance is crucial in the development of effective treatment and the design of future clinical studies.

Comparison of gefitinib and erlotinib efficacies as third-line therapy for advanced non-small-cell lung cancer

PURPOSE

The epidermal growth factor receptor inhibitors, gefitinib and erlotinib, are used as standard salvage therapy for advanced non-small-cell lung cancer (NSCLC). The aim of the present study was to compare their efficacies in this population.

PATIENTS AND METHODS

The Taiwan Cancer Registry and the National Health Insurance claim databases were searched for newly diagnosed patients with NSCLC from 2004 to 2007 who received gefitinib or erlotinib as third-line therapy. Overall survival (OS) and time to treatment failure (TTF) were determined from registered parameters. Treatment efficacies were compared by the log-rank test in total population and subsets with different clinical characteristics. The Cox's proportion hazard model was used to estimate the adjusted hazard ratios in multivariate analyses.

RESULTS

A total of 984 patients who received gefitinib (67%) or erlotinib (33%) were included. Patients receiving gefitinib or erlotinib had similar OS (median, 10.2 versus 9.9 months, p=0.524) and TTF (median, 5.5 versus 3.4 months, p=0.103). In multivariate analyses, both treatment groups had similar risk of overall mortality (adjusted hazard ratio [HR]=1.04, p=0.629) and treatment failure (adjusted HR=0.94, p=0.417). Comparing the treatments in subgroups based on age, tumour histology and gender also revealed no differences in OS and TTF. For patients who received gefitinib or erlotinib for more than 3 or 6 months, there was no difference in TTF but patients who received erlotinib had longer OS.

CONCLUSIONS

Gefitinib and erlotinib had similar efficacies as salvage therapy for advanced NSCLC in Taiwan.

Initial Progression-Free Survival after Non-First Line TKIs Therapy Potentially Guides Immediate Treatment after Its Failure in Advanced Non-Small Cell Lung Cancer

OBJECTIVE

The standard therapy after failure of the initial non-first line epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) treatment in advanced non-small cell lung cancer (NSCLC) has not yet been established. The aim of the current study was to identify whether the 2(nd) TKI treatment or chemotherapy (paclitaxel-containing or non-paclitaxel regimen) is the appropriate treatment for patients with NSCLC based on the efficacy of the initial TKIs.

METHODS

Seventy-two advanced NSCLC patients who had accepted 2(nd) TKIs or chemotherapy immediately after failure of the initial TKIs in non-first line setting from May 1, 2004 to January 31, 2010 at the Sun Yat-sen University Cancer Center were enrolled. The primary endpoint [2(nd) progression-free survival (PFS)] and the second endpoint [overall survival (OS)] were compared among the 2(nd) TKI and chemotherapy groups as well as their subgroups.

RESULTS

(1) Twenty-one patients were treated with 2(nd) TKIs, and 51 patients were administered chemotherapy after failure of the initial non-first line TKI treatment. There was nonsignificant difference in the responses (P=0.900) [2(nd) PFS (P=0.833) and OS (P=0.369)] between the 2(nd) TKI and chemotherapy groups. (2) In the 2(nd) TKI group, 9 patients exhibited PFS≥7 months. The initial TKI treatment group exhibited a longer 2(nd) PFS than the other 12 patients with an initial PFS<7 months (7 months vs. 2 months, P=0.019). However, these groups had nonsignificantly different OS (P=0.369). (3) In the chemotherapy group, patients with PFS<5 months exhibited longer 2(nd) PFS than those with PFS ≥ 5 months in the initial TKI treatment (3 months vs. 2 months, P=0.039). (4) In the chemotherapy group, patients treated with paclitaxel-containing regimen showed longer 2(nd) PFS than those treated with non-paclitaxel regimen (5 months vs. 2.3 months, P=0.043).

CONCLUSIONS

Patients with PFS≥7 months or <5 months under the initial TKI treatment potentially benefit from the 2(nd) TKI treatment or chemotherapy immediately after failure of the non-first line TKIs. The paclitaxel-containing regimen may improve the 2(nd) PFS. However, more patient samples are urgently needed to validate these findings.

Retreatment of gefitinib in patients with non-small-cell lung cancer who previously controlled to gefitinib: a single-arm, open-label, phase II study

Most patients with non-small-cell lung cancer (NSCLC) who initially respond to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) eventually experience progression of disease. Based on previous trials which showed second response after switching to another EGFR-TKI, we hypothesized that the reintroduction of gefitinib would lead to disease control rate (DCR) in more than 30% of patients. This was a single-arm, open-label, prospective, phase II trial of gefitinib for the treatment of advanced or metastatic NSCLC. Eligible patients had previously responded to, or had experienced disease stabilization with, initial gefitinib treatment for at least 3 months. Prior to retreatment, progressive disease (PD) should be observed, with at least one cytotoxic treatment following initial gefitinib failure. Twenty-three patients were recruited and defined as the intention to treat (ITT) group. Most of the enrolled patients were female (86.9%), never-smokers (91.3%), and adenocarcinoma patients (95.7%). Responses to initial gefitinib were partial response (PR) in 10 cases (43.5%) and stable disease (SD) in 13 cases (56.5%). PR and DCR were observed in 21.7% (5 patients) and 65.2% (15 patients) in the ITT group. Among 14 DNA samples, 13 cases had either exon 19 deletion or L858R point mutation, whereas one patient evidenced the wild-type EGFR gene. Re-initiation of EGFR-TKI can be considered as an option after failure of chemotherapy for those patients who previously controlled to EGFR-TKI treatment.

Effectiveness of erlotinib in advanced non-small cell lung cancer in cases of gefitinib resistance after treatment of more than 6 months

BACKGROUND

There have been reports on the use of erlotinib in non-small cell lung cancer (NSCLC) patients after gefitinib resistance occurs, and it has been stated that erlotinib may be beneficial in patients with long stable disease (SD) previously treated with gefitinib.

PATIENTS AND METHODS

We retrospectively studied gefitinib-resistant NSCLC patients with favorable clinical features, who received erlotinib following disease progression after gefitinib treatment of more than 6 months.

RESULTS

A total of 21 patients with NSCLC were included. Partial response was seen in 2 cases (9%), SD in 6 cases (19%), and progressive disease (PD) in 13 cases (62%). Disease control (DC) was achieved with erlotinib in 8 cases (36%). The median survival time (MST) was 369 days in DC cases and 133 days in PD cases. There were no statistical differences between DC cases and PD cases in terms of MST relative to sex, smoking and skin rash.

CONCLUSION

Subsequent erlotinib therapy is one of the therapeutic options in the treatment of gefitinib-resistant NSCLC in which prior gefitinib has shown long-term SD of more than 6 months.

EGFR-mutated oncogene-addicted non-small cell lung cancer: current trends and future prospects

Non-small cell lung cancer (NSCLC) tumours with certain mutations in the epidermal growth factor receptor (EGFR) tyrosine kinase have been termed 'oncogene addicted' to reflect their dependence on EGFR-mediated pro-survival signalling and their high susceptibility to apoptosis induced by EGFR tyrosine kinase inhibitors (EGFR-TKIs, e.g. gefitinib and erlotinib). The most common mutations (L858R and exon 19 deletions) predict an improved clinical response to first-line oral EGFR-TKIs compared with standard platinum-based chemotherapy in patients with advanced NSCLC. Moreover, these mutations are also prognostic of a relatively indolent course of disease, regardless of treatment, as compared with classical NSCLC. Treatment strategies for oncogene-addicted NSCLC are therefore distinct from those for non-oncogene addicted NSCLC, and will depend on the specific genetic mutation present.

Angiogenesis inhibition by the maleimide-based small molecule GNX-686

We investigated the anti-angiogenic properties of GNX-686, a newly identified maleimide-based small molecule. In vitro studies on HUVEC showed that GNX-686 inhibited cell growth with an ED(50) of 20-25 μM, while human HeLa tumor cells and non-transformed embryonic mouse fibroblasts were less sensitive for the drug. More importantly, at 4 μM, a concentration that was non-toxic to any cell in culture, GNX-686 showed a significant inhibitory effect on tube formation by HUVEC, indicating a profound anti-angiogenic activity. Angiogenesis inhibition was subsequenly tested in the chorioallantoic membrane (CAM) of the chicken embryo. A significant angiostatic activity was observed in the CAM model, and results were compared with the effect of bevacizumab, a well known and clinically used VEGF inhibitor. Under our experimental conditions, GNX-686 was found to be as effective as bevacizumab, significantly changing the morphology of the vascular network, as illustrated and quantified by the relative number of branching points and the relative mean mesh size of the vascular network. In another in vivo model of neovascularization, the mouse retinopathy of prematurity (ROP), the vascular network of GNX-686-treated mice was significantly altered, reducing the density of the retinal microvasculature, as compared to the control retinas. Immunohistochemical processing of the GNX-686 treated (4μM) eyes showed over 50% reduction of the number of cell nuclei associated with neovasculature, as compared to the control-treated eye. Taken together these results demonstrate that GNX-686 is a promising anti-angiogenic compound that could be developed for the treatment of diseases characterized by aberrant angiogenesis such as ocular pathologies and cancer.

Elevated BCRP/ABCG2 expression confers acquired resistance to gefitinib in wild-type EGFR-expressing cells

BACKGROUND

The sensitivity of non-small cell lung cancer (NSCLC) patients to EGFR tyrosine kinase inhibitors (TKIs) is strongly associated with activating EGFR mutations. Although not as sensitive as patients harboring these mutations, some patients with wild-type EGFR (wtEGFR) remain responsive to EGFR TKIs, suggesting that the existence of unexplored mechanisms renders most of wtEGFR-expressing cancer cells insensitive.

METHODOLOGY/PRINCIPAL FINDINGS

Here, we show that acquired resistance of wtEGFR-expressing cancer cells to an EGFR TKI, gefitinib, is associated with elevated expression of breast cancer resistance protein (BCRP/ABCG2), which in turn leads to gefitinib efflux from cells. In addition, BCRP/ABCG2 expression correlates with poor response to gefitinib in both cancer cell lines and lung cancer patients with wtEGFR. Co-treatment with BCRP/ABCG2 inhibitors enhanced the anti-tumor activity of gefitinib.

CONCLUSIONS/SIGNIFICANCE

Thus, BCRP/ABCG2 expression may be a predictor for poor efficacy of gefitinib treatment, and targeting BCRP/ABCG2 may broaden the use of gefitinib in patients with wtEGFR.

Clinical responses to EGFR-tyrosine kinase inhibitor retreatment in non-small cell lung cancer patients who benefited from prior effective gefitinib therapy: a retrospective analysis

Background

Gefitinib was the first epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) approved for the treatment of advanced non-small cell lung cancer (NSCLC). Few treatment options are available for NSCLC patients who have responded to gefitinib treatment and demonstrated tumor progression. The present study was conducted to evaluate the efficacy and toxicity of the 2^nd EGFR-TKI administration.

Methods

We retrospectively analyzed 11 patients who had obtained a partial response (PR) or stable disease (SD) with gefitinib treatment and were re-treated with EGFR-TKI after failure of the initial gefitinib treatment.

Results

Three patients (27%) were treated with gefitinib as the 2^nd EGFR-TKI, and 8 patients (73%) received erlotinib. Only one patient (9%) showed PR, 7 (64%) achieved SD, and 3 (27%) had progressive disease. The disease control rate was 73% (95% CI, 43% - 91%) and the median progression-free survival was 3.4 months (95% CI, 2 - 5.2). The median overall survival from the beginning of the 2^nd EGFR-TKI and from diagnosis were 7.3 months (95% CI, 2.7 - 13) and 36.7 months (95% CI, 23.6 - 43.9), respectively. No statistical differences in PFS or OS were observed between gefitinib and erlotinib as the 2^nd EGFR-TKI (PFS, P = 0.23 and OS, P = 0.052). The toxicities associated with the 2^nd EGFR-TKI were generally acceptable and comparable to those observed for the initial gefitinib therapy.

Conclusions

Our results indicate that a 2^nd EGFR-TKI treatment can be an effective treatment option for gefitinib responders.

Erlotinib as salvage treatment after failure to first-line gefitinib in non-small cell lung cancer

PURPOSE

Chemotherapy is the mainstay treatment for advanced non-small cell lung cancer (NSCLC). Gefitinib, an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), has been recently shown to be effective as a first-line treatment in Asian patients with advanced NSCLC, especially for those with favourable clinical features such as female, non-smoker and adenocarcinoma. However, resistance to gefitinib ensues invariably and there is little evidence as for the effectiveness of subsequent salvage treatment. The purpose of this study is to evaluate the efficacy of erlotinib, another EGFR-TKI, after failed first-line use of gefitinib.

METHOD

Retrospective review of NSCLC patients with favourable clinical features who received gefitinib as first-line treatment and subsequent salvage treatment with erlotinib.

RESULTS

A total of 21 patients with NSCLC were included in the study. Among them, 18 (85.7%) patients had disease control with gefitinib and 12 (57.1%) patients with salvage erlotinib. There was an association between the disease control with gefitinib and erlotinib (p = 0.031). The disease control rate of erlotinib was independent of the chemotherapy use between the two EGFR-TKIs.

CONCLUSION

For NSCLC patients with favourable clinical features, erlotinib was effective in those who had prior disease control with first-line gefitinib.

Pooled analysis of the reports of erlotinib after failure of gefitinib for non-small cell lung cancer

PURPOSE

The use of erlotinib after gefitinib failure in patients with non-small cell lung cancer (NSCLC) is not clearly clarified in clinical practice. We sought to compile the available clinical reports to better understand the effectiveness of erlotinib after failure of gefitinib.

METHODS

We searched published reports including erlotinib and gefitinib. Eleven reports were identified (published between November 2004 and December 2008). Advanced NSCLC who documented progressive disease (PD) for gefitinib 250 mg/day, received erlotinib 150 mg once daily.

RESULTS

A total of 106 patients were pooled from these studies. Asian was observed in 70.8%, women in 72.6%, adenocarcinoma in 85.1%, never smoker in 75.3%. In erlotinib therapy, there was observed in 9.9% in partial response (PR), 18.9% in stable disease (SD) and 70.8% in PD. Disease control (DC) rate for gefitinib and erlotinib was 71.7% and 29.2%, respectively. No significant difference of disease control rate (37.5% vs 21.7%, p=0.1503) and response rate (6.3% vs 8.7%, p=1.000) was observed between patients with EGFR mutations and those with wild type EGFR. The significantly different response on erlotinib therapy was observed in patients who had shown SD for gefitinib therapy (p=0.0095) and those who had a PFS of more than 6 months during gefitinib treatment (p=0.0261). The common toxicities were skin rash and diarrhea.

CONCLUSION

Erlotinib may produce clinical benefits in patients who had shown long SD on prior gefitinib therapy. Moreover, EGFR mutations were not positive predictors for erlotinib response after gefitinib failure.