Radiotherapy combined with gefitinib for patients with locally advanced non-small cell lung cancer who are unfit for surgery or concurrent chemoradiotherapy: a phase II clinical trial

Background

The objectives of this study were to determine the objective effective response rate, survival, and safety of radiotherapy combined with gefitinib in patients with locally advanced non-small cell lung cancer (NSCLC) who were unfit for surgery or concurrent chemoradiotherapy.

Methods

The patients with the locally advanced NSCLC who were unfit to receive surgery or concurrent chemoradiotherapy, received thoracic intensity-modulated radiotherapy (IMRT) combined with gefitinib 250 mg daily.

Results

29 patients were enrolled between July 2014 and March 2017. 28 patients was in the analysis. Of the 28 patients, 21 (75.0%) experienced a partial response, 5 (17.9%) had stable disease, and 2 (7.1%) experienced progression of disease. The objective response rate was 75.0%, and the disease control rate was 92.9%. The median follow-up time was 51 months. The disease progression showed in 25 (89.3%) patients, including local progression in 19 (67.9%) and distant metastasis in 16 (57.1%). The median overall survival and progression-free survival time (PFS) were 26 and 11 months, respectively. The 3-, 4-, 5-year survival rates were 39.0, 30.1 and 30.1%, respectively. The 3-, 4-, 5-year PFS rates were 14.3, 9.5 and 9.5%. Two patients developed grade 3 acute adverse events. Seven patients developed grade 2 acute irradiation pneumonitis, and there was no grade 3 acute irradiation pneumonitis.

Conclusions

For patients with locally advanced NSCLC who are not eligible for surgery or concurrent chemoradiotherapy, IMRT combined with gefitinib can improve the objective effective rate and is generally well-tolerated.

Combination of radiotherapy and targeted therapies in the treatment of locally advanced non-small cell lung cancer

Lung cancer is the most common cancer in the world. One third of patients with non-small cell lung cancer (NSCLC) are diagnosed with locally or regionally advanced unresectable disease at presentation. Currently, in this stage of disease, a combination of chemotherapy and radiotherapy is the standard treatment approach for patients with good performance status, and concomitant chemo-radiotherapy has demonstrated to be the best therapeutic approach. However, despite improvements in treatment, local tumor control remains suboptimal and distant metastases remain the major site of failure. The diversity of molecular abnormalities in NSCLC may partly contribute to its resistance to therapy. It is therefore widely accepted that one approach to improve the efficacy of cancer therapy is the development of rational combinations of anticancer agents that may exhibit synergistic interactions. The introduction of several biologic agents represents an important advance in the management of NSCLC and some of them have shown to have a synergistic effect when given in combination with radiotherapy and chemotherapy in preclinical and in clinical models. In the present review we discuss the rationale and the feasibility of these combinations and the first results available from clinical trials.

A phase I study of gefitinib with concurrent dose-escalated weekly docetaxel and conformal three-dimensional thoracic radiation followed by consolidative docetaxel and maintenance gefitinib for patients with stage III non-small cell lung cancer

BACKGROUND

Concurrent radiation and chemotherapy is the standard of care for good performance status patients with stage III non-small cell lung cancer. Locoregional control remains a significant factor relating to poor outcome. Preclinical and early clinical data suggest that docetaxel and gefitinib have radiosensitizing activity. This study sought to define the maximum tolerated dose of weekly docetaxel that could be given with daily gefitinib and concurrent thoracic radiation therapy.

PATIENTS AND MATERIALS

Patients with histologically confirmed, inoperable stage III non-small cell lung cancer and good performance status (Eastern Cooperative Oncology Group 0-1) were eligible for this study. Patients received three-dimensional conformal thoracic radiation to a dose of 70 Gy concurrently with oral gefitinib at a dose of 250 mg daily and intravenous, weekly docetaxel at escalating doses from 15 to 30 mg/m2 in cohorts of patients. Patients were given a 2-week rest period after the concurrent therapy, during which they received only gefitinib. After the 2-week rest period, patients received consolidation chemotherapy with docetaxel 75 mg/m2 given every 21 days for two cycles. Maintenance gefitinib was continued until disease progression or study completion.

RESULTS

Sixteen patients were enrolled on the study between December 2003 and April 2007 with the following characteristics: median age, 64 years (range 43-79 years); M/F: 9/7; and performance status 0/1, 1/15. Dose-limiting pulmonary toxicity and esophagitis were encountered at a weekly docetaxel dose of 25 mg/m2, resulting in a maximum tolerated dose of 20 mg/m2/wk. Overall, grade 3/4 hematologic toxicity was observed in 27% of patients. Grade 3/4 esophageal and pulmonary toxicities were reported in 27% and 20% of patients, respectively. The overall response rate was 46%, and the median survival for all patients was 21 months.

CONCLUSIONS

Concurrent thoracic radiation with weekly docetaxel and daily gefitinib is feasible but results in moderate toxicity. For further studies, the recommended weekly docetaxel dose for this chemoradiation regimen is 20 mg/m2.

Combination of radiotherapy and chemotherapy in locally advanced NSCLC

The combination of radiotherapy and chemotherapy is considered to be a standard approach for patients with locally advanced, stage III non-small-cell lung cancer. The current state of the art of combined radiochemotherapy supported by evidence-based data is presented. As shown in the meta-analyses, the concurrent radiochemotherapy gives a superior outcome in terms of survival compared with sequential delivery of both modalities. This is obtained at the expense of higher toxicity, which makes further intensification of radiochemotherapy challenging. Eligibility of patients with non-small-cell lung cancer for such an approach is limited. The new methods to improve treatment results, such as selection of proper strategies, incorporation of molecular agents into combined treatment and radiotherapy technique modifications are discussed.

Combined chemo-radiotherapy for locally advanced non-small cell lung cancer: current status and future development

Currently, combinations of chemotherapy and radiotherapy are the standard treatment approach for locally advanced NSCLC patients. Concomitant chemo-radiotherapy, although associated with increased acute toxicity, has demonstrated to be the better strategy over sequential chemoradiotherapy, and it is to be considered a standard approach in patients with good performance status (0-1). However, the approach to locally advanced NSCLC and to chemo-radiotherapy regimens remains heterogeneous among oncologists, and clinical outcomes are yet disappointing. Thus, the search of new strategies is mandatory. The main fields of research aiming at improving the survival of locally advanced NSCLC patients are: the addition of further combination chemotherapy as induction or consolidation to concurrent chemo-radiotherapy, and the integration of molecularly targeted therapies into conventional chemo-radiotherapy regimens.

Antimetabolite radiosensitizers

Radiosensitization with antimetabolites has improved clinical outcome for patients with solid malignancies, especially cancers of the GI tract, cervix, and head and neck. Fluorouracil (FU) and hydroxyurea have been widely used clinically during the last four decades, and promising results have been observed more recently with gemcitabine. Although the antimetabolites all target DNA replication, they differ with respect to the mechanisms by which they produce radiosensitization. The antimetabolite radiosensitizers may inhibit thymidylate synthase (TS) or ribonucleotide reductase, and the nucleoside/nucleobase analogs can be incorporated into DNA. Radiosensitization can result from chemotherapy-induced increase in DNA double-strand breaks or inhibition of their repair. Studies of repair pathways involved in radiosensitization with antimetabolites implicate base excision repair with the TS inhibitors, homologous recombination with gemcitabine, and mismatch repair with FU and gemcitabine. Gemcitabine can also stimulate epidermal growth factor receptor (EGFR) phosphorylation; inhibiting this effect with EGFR inhibitors can potentiate cytotoxicity and radiosensitization. Additional work is necessary to determine more precisely the processes by which antimetabolites act as radiation sensitizers and to define the optimal sequencing of these agents with EGFR inhibitors to provide better guidance for clinical protocols combining these drugs with radiotherapy.

Definitive Chemoradiation for the Treatment of Locally Advanced Non–Small-Cell Lung Cancer

A third of patients with newly diagnosed non–small-cell lung cancer (NSCLC) have locally advanced disease not amenable for curative resection. Addition of chemotherapy to thoracic radiation improves survival in patients with locally advanced NSCLC when compared with thoracic radiation alone. Over the past two decades, we have made slow but steady progress in improving the outcomes of therapy in this subset of patients. This review summarizes the past two decades of research and outlines the direction we need to pursue to significantly enhance the outcomes. The widespread use of positron emission tomography (identifying those with occult distant metastatic disease and sparing them combined-modality therapy), improved radiation techniques, and better supportive care resulting in improved chemotherapy delivery have resulted in improved outcomes. There is considerable interest in studying the role of higher doses of thoracic radiation (74 Gy) in this disease, and this is the subject of an ongoing intergroup study. Despite some recent setbacks, molecularly targeted therapies need to be studied carefully in combination with chemoradiotherapy. There is an urgent need to develop regimens that incorporate chemotherapy agents that can be administered at doses that are systemically active and yet tolerable.