Gefitinib Failure Research Articles

Survival analysis for older patients with epidermal growth factor receptor mutation-positive advanced non-small cell lung cancer after progression of first-line gefitinib.

Currently, little studies focus on treatment strategies and survival after progression of gefitinib in older patients with epidermal growth factor receptor )EGFR( mutant advanced non-small-cell lung cancer (NSCLC). The aim of this study was to investigate the influence of different treatment modalities on survival after progression of gefitinib in older patients. This is a retrospective analysis included 62 consecutively recruited EGFR-mutant advanced NSCLC patients aged over 70 years who failed first-line gefitinib between 2008 and 2018. Kaplan-Meier method was used to estimate curves for overall survival (OS). Multivariate analysis identified independent prognostic risk factors of OS. The median age at diagnosis was 75 years (range, 70-88years). The median progression-free survival of gefitinib was 11.0 months. Forty-four (69.4%) patients continued gefitinib beyond progressive disease (PD), and median gefitinib treatment duration was 18.0 months. Only 67.7% patients received anticancer treatments after discontinuation of gefitinib. The median OS was 24.5 months (95% confidence interval [CI], 19.7-29.3 months). After failure of gefitinib, the osimertinib only group had significantly improved OS compared with chemotherapy or palliative care only groups (37.5 versus 17.5 and 15.3 months, respectively; P=.017). Multivariate analysis showed that continuous gefitinib after Response Evaluation Criteria in Solid Tumor-defined PD (hazards ratio [HR] 0.273, 95% CI: 0.132-0.564, P<.001), osimertinib treatment (HR 0.244, 95% CI: 0.122-0.487, P<.001), and better performance status (HR 0.360, 95% CI: 0.163-0.796, P=.012) were significantly and independently correlated with better survival. For older patients with EGFR-mutant advanced NSCLC, EGFR tyrosine kinase inhibitors are the most important treatment. Survival benefit of chemotherapy after failure of gefitinib seems limited.

Efficacy and dose of afatinib in patients with non-small cell lung cancer after failure of prior gefitinib or erlotinib treatment.

BackgroundWe report a subgroup analysis of afatinib with respect to its efficacy, safety, and the long‐term survival of patients in a Named Patient Use program at a single institution.MethodsWe analyzed 60 patients with stage IV non‐small cell lung cancer (NSCLC) who had been treated with ≥1 line of platinum‐based chemotherapy and had activating epidermal growth factor receptor (EGFR) mutations or disease control for ≥6 months with prior EGFR inhibitors. Afatinib was started on a daily dose of 50 mg, which was decreased according to the adverse events and tolerability.ResultsA total of 13 patients achieved partial remission, whereas 33, 12, and two showed stable disease, had progression, and were not evaluable, respectively, resulting in an objective response rate and disease control rate of 21.7% and 76.7%, respectively. The median progression‐free survival (PFS) was 5.4 (95% confidence interval [CI]: 4.0–7.7) months and median overall survival (OS) was 10.1 (8.5–13.6) months. Toxicities leading to drug discontinuation were experienced by four patients (6.7%). Grade 3 diarrhea occurred in 10 patients (16.7%), and afatinib dose reductions were required in 35 patients. The PFS and OS were significantly longer for patients whose dose was reduced to 40 or 30 mg than for those without dose reduction (7.0 vs 3.1 months and 13.5 vs 8.1 months, respectively, p < 0.05).ConclusionsThe efficacy of afatinib was similar to that identified in the global data without unexpected adverse events. Survival analyses support the currently approved dose of afatinib as first‐line treatment for NSCLC.

494P - Comparison of pattern of disease progression and prevalence of acquired T790M mutation in Malaysia patients with EGFR mutant lung adenocarcinoma upon failure of first-line afatinib, gefitinib and erlotinib

BackgroundPatients receiving first-line afatinib, gefitinib or erlotinib for epidermal growth factor receptor (EGFR) mutant advanced non-small cell lung cancer develop progression of disease (PD) after an average of 9-13 months. MethodsA retrospective analysis of PD pattern and prevalence of acquired T790M mutation among patients failing first-line afatinib versus gefitinib or erlotinib at University Malaya Medical Centre from 1st January 2015 to 31th December 2018. ResultsOf 87 patients who developed PD while on first-line EGFR-tyrosine kinase inhibitor (TKI) treatment, 19 (21.8%) were on afatinib, 49 (56.3%) were on gefitinib, and 19 (21.8%) were on erlotinib. The median progression-free survival (mPFS) of these patients is as shown in the table. Of 20 patients (23.0%) who developed new symptomatic brain metastases, one (5.0%) had new leptomeningeal metastases, three (15.0%) had both new leptomeningeal metastases and solid brain metastases, and the remaining 16 (80.0%) had new solid brain metastases only. New leptomeningeal metastases occurred in one patient treated with afatinib and three patients treated with gefitinib. Forty-nine patients (56.3%) were investigated for acquired T790M mutation either by plasma biopsy or tissue biopsy or both. The prevalence of acquired T790M mutation was 61.2%. There was no difference in the pattern of PD or prevalence of acquired T790M mutation among patients treated with afatinib, gefitinib or erlotinib.Table494PTablePattern of PDPatients with PD (n = 87)Afatinib (n = 19)Gefitinib (n = 49)Erlotinib (n = 19)p-valueMedian PFS, months11.013.110.97.80.479New brain metastases, No. (%)Yes No20 (23.0) 67 (77.0)5 (26.3) 14 (73.7)12 (24.5) 37 (75.5)3 (15.8) 16 (84.2)0.692New solid brain lesion metastases, No (%)Yes No19 (21.8) 68 (78.2)4 (21.1) 15 (78.9)12 (24.5) 37 (75.5)3 (15.5) 16 (84.2)0.735New leptomeningeal metastases, No. (%)Yes No4 (4.6) 83 (95.4)1 (5.2) 18 (94.8)3 (6.1) 46 (93.9)0 19 (100)0.550No. of patients tested for acquired T790M mutationn = 49n = 14n = 27n = 8p-valueAcquired T790M mutation detected, No. (%)Yes No30 (61.2) 19 (38.8)9 (64.3) 5 (35.7)16 (59.3) 11(40.7)5 (62.5) 3 (37.5)0.949 ConclusionsNew leptomeningeal metastases were uncommon in patients receiving first-line EGFR-TKI. The choice of first-line first- or second generation EGFR-TKI did not influence the pattern of PD and prevalence of acquired T790M mutation. However, patients receiving afatinib appeared to have longer mPFS than those on gefitinib or erlotinib. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

Re-challenge of afatinib after 1st generation EGFR-TKI failure in patients with previously treated non-small cell lung cancer harboring EGFR mutation.

Re-challenge of erlotinib after gefitinib failure is reported to yield some benefit in patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutation. However, little is known about the re-challenge of afatinib after 1st generate on EGFR tyrosine kinase inhibitor (TKI) failure. From May 2015 to August 2018, 62 patients with advanced NSCLC harboring sensitive EGFR mutation received afatinib after gefitinib and/or erlotinib failure at our institution was included in our retrospective study. The overall response rate (ORR) and disease control rate (DCR) of afatinib as re-challenge were 17.0% and 79.2%, respectively. The median time on treatment of 1st generation EGFR-TKI (1st TKI) was 14months. By multivariate analysis, smoking, performance status (PS), and time on treatment of 1st TKI with more than 10months were confirmed to be independent prognostic factors predicting a worse progression-free survival (PFS), and significant prognostic markers for overall survival (OS) were PS and time on treatment of 1st TKI with more than 10months, especially in patients with exon 19 deletion. Re-challenge of afatinib was identified as one of the therapeutic options after 1st TKI failure in the patients with advanced NSCLC harboring EGFR mutation when the time of treatment by prior 1st TKI is more than 10 months.

Treatment response to osimertinib in a patient with leptomeningeal metastasis from lung adenocarcinoma following failure of gefitinib and erlotinib: A case report.

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are effective in the treatment of advanced non-small-cell lung cancer (NSCLC) with leptomeningeal metastases (LM); however, a proportion of the patients with resistant tumors do not benefit from EGFR-TKI treatment. In the present study the case of a female patient with advanced lung adenocarcinoma harboring the EGFR L858R mutation (encoded in exon 21) who developed intracranial metastases following treatment with erlotinib after gefitinib failure is reported. The patient achieved a partial response (PR) after four cycles of chemotherapy with pemetrexed/cisplatin. However, after 4 months, LM were detected. The patient was treated with osimertinib, a third-generation EGFR-TKI, but the LM continued to progress and the patient eventually succumbed to the disease (overall survival, 6 months). Therefore, LM in patients without the EGFR T790M mutation (encoded in exon 20) appear to be resistant to treatment with the third-generation TKI osimertinib, which may be associated with human epidermal growth factor receptor 2 amplification. Further clinical trials are required to confirm our results.

P2.03-055 Comparison of Afatinib Versus Erlotinib for Advanced Non-Small-Cell Lung Cancer Patients with Resistance to EGFR-TKI

Afatinib, an irreversible ErbB-family blocker, has shown activity for patients with advanced non-small-cell lung cancer (NSCLC) after failure of gefitinib or/and erlotinib in LUX-LUNG1 trial; however, efficacy data of EGFR-TKI re-challenge with afatinib is insufficient.

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

Ahead of Print article withdrawn by publisher.

Treatment and prognosis after progression in long-term responders to EGFR-tyrosine kinase inhibitor in advanced non-small cell lung cancer.

IntroductionThe aim of this study was to investigate the treatment and prognosis of advanced non-small cell lung cancer (NSCLC) patients after failure of long-term treatment with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI).Material and methodsWe retrospectively analyzed all NSCLC patients with EGFR-TKI (gefitinib or erlotinib) treatment at our institution between 2011 and 2013 who progressed after at least stable disease on erlotinib or gefitinib for more than 6 months. Survival curves were plotted using the Kaplan-Meier method. The Cox proportional hazard model was used for multivariate analysis.ResultsIn total, 521 patients were administered EGFR-TKI. Of these, 298 patients received EGFR-TKI with progression-free survival less than 6 months (group A), and the other 223 patients more than 6 months (group B). There was a significant difference in overall survival (OS) between group A and group B (7.2 months vs. 5.0 months, p < 0.0001). The median OS for group B patients was 5.0 months. Among the 223 patients in group B, 38 patients received chemotherapy with continued EGFR-TKI after failure of prior gefitinib or erlotinib treatment, 92 with chemotherapy alone and 93 with best supportive care. Patients who continued gefitinib or erlotinib had a significantly longer OS (median: 7.5 months), followed by chemotherapy (5.5 months) and best supportive care (4.0 months) (p < 0.001).ConclusionsThe prognosis of advanced NSCLC patients after failure of long-term treatment with EGFR-TKI was poor. Chemotherapy with continued EGFR-TKI beyond progression of long-term responders was feasible and led to prolonged OS in advanced NSCLC patients.

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.

Fighting cancer drug resistance: Opportunities and challenges for mutation-specific EGFR inhibitors.

Multiple mutations in the EGFR gene are a major cause for the failure of Erlotinib and Gefitinib in the treatment of patients harboring non-small-cell lung cancer (NSCLC) who initially responded to this therapy. The development of these tyrosine kinase inhibitors (TKIs) is going back to the early 90s, where cancer was widely considered and fully treated as a disease of an organ. Fundamental gain of knowledge in cell biology in general and cancer genetics in particular led us to where we currently stand: cancer is a disease that originates in the genome. Fast and affordable gene sequencing paved the way and opened our eyes for the genetic instability of many cancers, particularly EGFR driven NSCLC. This might allow highly rational and personal therapies by aiming at a very particular wild type and mutant kinase pattern. However, the paradigm "one disease - one target - one drug" is currently challenged. Both activating and deactivating EGFR mutations are known to render the development of novel targeted drugs difficult. Among all lung adenocarcinomas, only 20% are driven by EGFR and only a subpopulation has an activating mutation (e.g. L858R), making them sensitive to first generation EGFR inhibitors. Unfortunately, most of them acquire second deactivating mutations (e.g. T790M) during treatment, leading to a complete loss of response. Are specific inhibitors of the double EGFR mutant L858R/T790M the magic bullet? Much scientific evidence but also high expectations justify this approach. Structural biology of EGFR mutants constitutes the basis for highly rational approaches. Second generation pan EGFR inhibitors inhibiting wild type (WT) and mutant EGFR like Afatinib suffer from dose-limiting adverse effects. Inhibition of WT EGFR is considered to be the culprit. Third generation EGFR inhibitors follow two strategies. Mutant selectivity and improved target residential time. These inhibitors display high mutant selectivity and irreversible binding patterns while sparing WT EGFR activity, hence enhancing tumor selectivity while minimizing adverse effects. Third generation EGFR inhibitors are still undergoing preclinical and clinical evaluation. The most advanced are Rociletinib and AZD9291 which displayed encouraging preliminary clinical phase II data regarding response and adverse effects. In the current review we show both a medicinal chemists' approach toward the design of third generation EGFR inhibitors as well as a detailed overview of the development of EGFR inhibitors over the last decade. High interdisciplinary approaches, such as structural biology and time-resolved tumor genetics pave the way toward the development of drugs that target EGFR mutants. This might lead to highly effective targeted and personalized therapies with enhanced response rates for a minor cohort of patients which have to undergo continuous gene sequencing, hence enabling therapies with tailor-made TKIs.

Erlotinib in combination with pemetrexed/cisplatin for leptomeningeal metastases and cerebrospinal fluid drug concentrations in lung adenocarcinoma patients after gefitinib faliure.

Limited treatment options are available for lung cancer with brain metastases. Recent reports indicated that erlotinib and pemetrexed had synergistic effects in lung adenocarcinoma. Thus, we speculated that erlotinib plus pemetrexed/cisplatin may be more effective for the treatment of refractory central nervous system metastases in patients after gefitinib failure. Six lung adenocarcinoma patients with leptomeningeal metastasis (LM) who showed initial good response to gefitinib and subsequent gefitinib resistance were enrolled in this retrospective study. Five of the six patients had an epidermal growth factor receptor (EGFR) mutation in the primary tumor tissues or plasma. One patient showed complete remission, two patients showed a partial response, and two patients had stable disease. Performance and symptoms improved in the six patients. The survival time after the combination therapy was from 8 to 15months (median, 9months). There was no significant difference in cerebrospinal fluid (CSF) penetration rates of erlotinib between the erlotinib-only and the combination groups (P = 0.44). Erlotinib combined with pemetrexed/cisplatin may be effective in the treatment of LM in EGFR mutation patients after gefitinib failure. Small but measurable penetration of erlotinib and pemetrexed into the CSF was observed.

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.

Clinical characteristics of non-small cell lung cancer patients who experienced acquired resistance during gefitinib treatment

BackgroundThe NSCLC patients who experienced good clinical responses to an EGFR-TKI will inevitably develop acquired resistance. A great deal of research is being carried out to discover the molecular mechanisms underlying this resistance. In comparison, few studies have been conducted to find out about the clinical characteristics of acquired resistance in the patients who had responded to an EGFR-TKI. Herein we investigated clinical characteristics of NSCLC patients who experienced acquired resistance during gefitinib therapy. Patients and methodsWe reviewed NSCLC patients who showed a clinical benefit from initial gefitinib therapy. All clinical data were obtained from 11 centers of Korean Molecular Lung Cancer Group (KMLCG). The clinical manifestations of acquired resistance, time to progression (TTP), and post-progression survival (PPS) after gefitinib failure were analyzed retrospectively. ResultsA total of 417 patients were recruited. Median TTP was 10.2 months (95% CI, 9.5–10.9). TTP showed a significant longer duration in female, non-smoker, and patients with adenocarcinoma. At the time of acquired resistance, 63.3% of the patients showed symptomatic deterioration. Sites of disease progression were as follows: primary lung lesion in 58.4%, previous metastasis in 38.3%, and new metastasis in 54.2%. Patients with EGFR wild type showed a tendency of higher frequency in symptomatic deterioration and newly development of CNS metastasis compared with patients with EGFR mutation. There was a significant difference in newly development of lung metastasis between patients with exon 19 deletion and those with L858R mutation (41.4% vs. 6.3%, p=0.02). PPS was 8.9 months (95% CI, 7.4–10.4). Smoking history, PS, new CNS lesion and subsequent chemotherapy were independent factors for PPS. ConclusionThis study suggests that clinical manifestations of acquired resistance may be different according to EGFR mutation status and EGFR mutation genotype. In addition, subsequent chemotherapy confers clinical benefit in terms of PPS in NSCLC patients who experienced acquired resistance after gefitinib therapy.

Re-administration after the failure of gefitinib or erlotinib in patients with advanced non-small cell lung cancer.

Few treatment options are available for advanced non-small cell lung cancer (NSCLC) patients who have failed of gefitinib or erlotinib treatment in second/third-line treatment. The aim of this study was to investigate the efficacy of re-administration of the same TKI after failure of gefitinib or erlotinib. The clinical data of 33 patients with advanced NSCLC were retrospectively analyzed. All of the patients were given the same TKI treatment after the failure of gefitinib or erlotinib. Survival analysis was evaluated by Kaplan-Meier method. Twenty patients (60.6%) were re-administration with gefitinib as the 2(nd) EGFR-TKI, and thirteen patients (39.4%) received erlotinib. One patient (3.0%) showed partial response (PR), 14 (42.4%) achieved stable disease (SD), and 18 (54.5%) had progressive disease (PD). The disease control rate was 45.5% and the median progression-free survival was 1.5 months (95% CI: 0.6-2.3 months). The PFS in patients who got disease control in the prior TKI was 2.2 and 1.2 months in the progression disease cases (P=0.29), the DCR was 54.5% and 27.3% in two group, respectively (P=0.26). Re-administration of TKI seems to be a potential therapeutic option for treatment of selected advanced NSCLC patients after failure of gefitinib or erlotinib, especially for the patients with NSCLC who once responded from the prior TKI treatment.

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

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. 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). 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). 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.

Abstract 964: Gefitinib resistance due to STAT3-mediated Akt activation in lung cancer cells.

Abstract Epidermal Growth Factor Receptor (EGFR) tyrosine kinase inhibitors (TKIs), including gefitinib and erlotinib, are effective drugs for a subset of non-small cell lung cancer. Gefitinib binds to the tyrosine kinase domain of EGFR and hence inactivates its downstream prosurvival signaling pathways, including PI3k/Akt and MAPK pathways. However, most patients received gefitinib eventually developed resistance to this drug. In this study, we demonstrated that in gefitinib-treated A549 cells (human lung cancer cell line), Akt activation undergoes a time-dependent recovery following an initial inhibition by gefitinib. Since constant activation of Akt has been associated with treatment failure of gefitinib in lung cancer cells, exploring the mechanisms that lead to Akt restoration should provide new insights into the drug resistance and therapeutic efficacy. For that purpose, alterations in Akt activation and other signaling pathways, including MAPK and STAT3, involved in EGFR-mediated cellular responses were determined in A549 cells treated with gefitinib. Among them, we found that activation of STAT3 was inhibited in the cells without gefitinib treatment. Gefitinib treatment inhibited EGFR phosphorylation on tyrosine 1086 (Y1086), which leads to STAT3 activation. Further studies showed that interruption of the STAT3 signaling by either chemical inhibitor or siRNA against STAT3 prevented fast recovery of Akt activation and enhanced gefitinib-induced suppression of cell proliferation. Taken together, these data suggest that activation of STAT3 is an intrinsic mechanism of drug resistance in response to EGFR TKIs. Combinational targeting on both EGFR and STAT3 may enhance the efficacy of gefitinib or other EGFR TKIs on lung cancer. Citation Format: Kai Wu, Yongju Lu, Bailing Chen, Qingshan Chang, Ping Qiu, Miaomiao Yu. Gefitinib resistance due to STAT3-mediated Akt activation in lung cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 964. doi:10.1158/1538-7445.AM2013-964

Efficacy of erlotinib after the failure of gefitinib in patients with metastasis of non-small cell lung cancer with unknown EGFR mutation status

To evaluate the efficacy of erlotinib in patients with metastasis of non-small cell lung cancer who had benefits from initial gefitinib treatment but finally demonstrated resistance, especially in those of unknown EGFR mutation status, and to compare the efficacy of erlotinib between patients who received erlotinib immediately after gefitinib failure and those who received chemotherapy before erlotinib. Forty Chinese patients who had been treated with erlotinib (150 mg daily) after gefitinib (250 mg daily) failure were evaluated retrospectively. All of these patients had achieved gefitinib treatment for at least three months with response of partial remission or stable disease. Among them, 16 patients shifted to erlotinib immediately after progression (Group G-E), and the other 24 patients inserted chemotherapy between gefitinib and erlotinib (Group G-C-E). In the whole group, the disease control rate (DCR) of erlotinib was 52.5% (21/40) while the objective response rate (RR) was only 10.0% (4/40). The RR of the group G-E was 6.2% and the group G-C-E was 12.5%, and the DCR was 56.2% and 50.0% in the two groups, respectively, both without significant differences (P = 0.638 and P = 0.755). There was no correlation between the efficacy of erlotinib and that of initial gefitinib in both group G-E and group G-C-E (P = 0.365 and P = 0.658). The median progression-free survival (PFS) and overall survival (OS) for the erlotinib treatment were 3.0 and 12.0 months in the 40 patients. Statistically no significant difference was observed in PFS (4 months in the group G-E and 2 months in the group G-C-E, P = 0.768) and OS (12 months in both Groups, P = 0.510). Erlotinib can be considered either immediately after gefitinib failure or following the insertion of chemotherapy after gefitinib failure in progressive non-small cell lung cancer patients who initially benefited from gefitinib.

Chemotherapy Effectiveness After First-Line Gefitinib Treatment for Advanced Lepidic Predominant Adenocarcinoma (Formerly Advanced Bronchioloalveolar Carcinoma): Exploratory Analysis of the IFCT-0401 Trial

This study explored whether chemotherapy after first-line gefitinib was effective in patients with advanced lepidic predominant adenocarcinoma (LPA), formerly advanced bronchioloalveolar carcinoma, who were enrolled in the Intergroupe Francophone de Cancérologie Thoracique (IFCT)-0401 trial. Overall, 88 patients presenting advanced LPA were enrolled in the IFCT-0401 trial, receiving gefitinib as first-line therapy. No predefined second-line treatment was mandatory in the case of progression or limiting toxicity under gefitinib. However, the carboplatin plus paclitaxel regimen was recommended for patients with a performance status (PS) 0 or 1 and gemcitabine monotherapy for those with a PS 2. For these patients, data concerning treatment efficacy was collected from the IFCT-0401 trial database. In total, 47 patients (53%) received second-line treatment after the failure of gefitinib, with 43 having PS 0 or 1. Regarding treatment, 43 were treated with chemotherapy, with 38 receiving a platinum-doublet regimen (taxane-based, n = 29; gemcitabine-based, n = 9) and five receiving monotherapy (gemcitabine, n = 3; pemetrexed, n = 2). The overall response rate (ORR) to chemotherapy was 21% (95% confidence interval [CI]: 10-36), disease control rate 56% (95% CI: 40-71), and median progression-free survival (PFS) 3.0 months (95% CI: 2.4-4.9). For patients receiving a platinum doublet (n = 38), ORR was 21% (95% CI: 10-37), with disease control rate being 55% (95% CI: 38-71), and median PFS 2.9 months (95% CI: 2.4-4.4). For patients receiving taxane-based regimen (n = 29) and gemcitabine-based regimen (n = 12), ORR was 28% and 0%, respectively, with a median PFS of 3.3 and 2.0 months, respectively, (p = 0.0243). The two patients receiving pemetrexed experienced a prolonged response. Multivariate Cox model analysis revealed that only the use of taxane-based chemotherapy or pemetrexed was related to PFS. Platinum-doublet chemotherapy showed some effectiveness in treating advanced LPA patients after first-line gefitinib. Our findings also suggest that taxane-based chemotherapy and pemetrexed should be investigated further in future clinical trials.

1344 - Is Change to Another Treatment Immediately After Failure of Gefitinib Recommended in Patients Harboring Activating Epidermal Growth Factor Receptor Mutations

ABSTRACT Background Gefitinib is an effective agent for use in treating patients suffering from non-small cell lung cancer (NSCLC) with activating epidermal growth factor receptor (EGFR) mutations. However, no optimal strategies have been established for treating these patients after gefitinib fails. Here, we conducted a retrospective study to assess the survival benefit of continued gefitinib treatment in these cases. Patients and methods We analyzed gefitinib responders with activating EGFR mutations who developed progressive disease (PD) during the course of therapy. Prognostic variables were analyzed using a Cox proportional-hazards model. Results Among the 146 patients retrospectively reviewed, exon-19 deletion mutations and L858R point mutations were detected in 78 and 68 patients, respectively. Median survival time after PD confirmation was 14.9 months (95% confidence interval [CI]: 7.9-21.9), and the median duration of continued gefitinib therapy beyond PD was 3.4 months. Statistical analysis showed that good performance status (0-1) (hazard ratio [HR]: 0.7), progression of previously evaluated lesion (HR: 0.6), and at least 3 months of continued treatment (HR: 0.4) were independent prognostic factors. Conclusion Continuation of gefitinib beyond PD is an effective optional treatment in EGFR-mutated patients. Disclosure All authors have declared no conflicts of interest.

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.