A Phase I Study of Pemetrexed, Carboplatin, and Concurrent Radiotherapy in Patients with Locally Advanced or Metastatic Non–Small Cell Lung or Esophageal Cancer

Meta-analysis of concomitant versus sequential radiochemotherapy in locally advanced non-small-cell lung cancer

PURPOSE

The previous individual patient data meta-analyses of chemotherapy in locally advanced non-small-cell lung cancer (NSCLC) showed that adding sequential or concomitant chemotherapy to radiotherapy improved survival. The NSCLC Collaborative Group performed a meta-analysis of randomized trials directly comparing concomitant versus sequential radiochemotherapy.

METHODS

Systematic searches for trials were undertaken, followed by central collection, checking, and reanalysis of updated individual patient data. Results from trials were combined using the stratified log-rank test to calculate pooled hazard ratios (HRs). The primary outcome was overall survival; secondary outcomes were progression-free survival, cumulative incidences of locoregional and distant progression, and acute toxicity.

RESULTS

Of seven eligible trials, data from six trials were received (1,205 patients, 92% of all randomly assigned patients). Median follow-up was 6 years. There was a significant benefit of concomitant radiochemotherapy on overall survival (HR, 0.84; 95% CI, 0.74 to 0.95; P = .004), with an absolute benefit of 5.7% (from 18.1% to 23.8%) at 3 years and 4.5% at 5 years. For progression-free survival, the HR was 0.90 (95% CI, 0.79 to 1.01; P = .07). Concomitant treatment decreased locoregional progression (HR, 0.77; 95% CI, 0.62 to 0.95; P = .01); its effect was not different from that of sequential treatment on distant progression (HR, 1.04; 95% CI, 0.86 to 1.25; P = .69). Concomitant radiochemotherapy increased acute esophageal toxicity (grade 3-4) from 4% to 18% with a relative risk of 4.9 (95% CI, 3.1 to 7.8; P < .001). There was no significant difference regarding acute pulmonary toxicity.

CONCLUSION

Concomitant radiochemotherapy, as compared with sequential radiochemotherapy, improved survival of patients with locally advanced NSCLC, primarily because of a better locoregional control, but at the cost of manageable increased acute esophageal toxicity.

New data integrating multitargeted antifolates into treatment of first-line and relapsed non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) represents approximately 80% of all lung cancers. With modern platinum- based combination regimens, overall median survival has reached 9-12 months. Antifolates are active against several solid tumors and hematologic malignancies. The cytotoxic action of antifolates is mainly related to their ability to inhibit several different folate-dependent enzymes involved in DNA synthesis. Pemetrexed is a novel multitargeted antifolate that inhibits at least 3 of the enzymes involved in purine and pyrimidine synthesis: thymidylate synthase (TS), dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT). Pemetrexed was approved for the treatment of relapsed NSCLC as it produced equivalent response and survival rates and less toxicity compared with docetaxel. Pemetrexed in combination with platinum analogues or with gemcitabine showed equivalent clinical impact compared with standard combinations of platinum plus third-generation agents. We analyze the potential implications of pemetrexed's role in first-line chemotherapy of NSCLC as well as hints of differential cytotoxic action according to histology, new schedules of vitamin supplementation, and target enzymes expression levels. Issues of pharmacogenomics are becoming relevant in defining pemetrexed efficacy. Chemosensitivity was significantly linked to low levels of TS, GARFT, and DHFR in preclinical models. Consequently, the differential expression of TS according to histology might explain the different activity of pemetrexed according to histology, as recently postulated.

Tracheoesophageal fistula formation in patients with lung cancer treated with chemoradiation and bevacizumab

PURPOSE Tracheoesophageal fistulae are rare complications of thoracic cancers and their treatments. Novel antiangiogenic agents in cancer treatment such as bevacizumab potentially impact wound healing and may contribute to tracheoesophageal fistula development. PATIENTS AND METHODS We conducted two independent phase II clinical trials in small-cell lung cancer and non-small-cell lung cancer using bevacizumab in combination with chemotherapy and radiation. Both trials were intended to assess preliminary efficacy and safety outcomes. Results For the limited-stage small-cell lung cancer trial, 29 patients were enrolled beginning April 2006, and closed early due to toxicity in March 2007 (14-month median follow-up). The locally advanced, non-small-cell lung cancer trial opened with enrollment limited to five patients in February 2007, and closed early due to safety in December 2007. In each trial, we observed tracheoesophageal fistulae development and related morbidity and mortality, prompting early trial closures, US Food and Drug Administration warnings, and a change in bevacizumab labeling. CONCLUSION The current data from the final reports from these two trials suggest bevacizumab and chemoradiotherapy are associated with a relatively high incidence of tracheoesophageal fistulae formation in both small-cell lung cancer and non-small-cell lung cancer settings. Strategies to safely incorporate novel antiangiogenic agents into combined-modality therapy in lung cancer are needed.

PROCLAIM: A phase III study of pemetrexed, cisplatin, and radiation therapy followed by consolidation pemetrexed versus etoposide, cisplatin, and radiation therapy followed by consolidation cytotoxic chemotherapy of choice in locally advanced stage III non-small-cell lung cancer of other than predominantly squamous cell histology

This clinical trial summary provides the background and rationale for a randomized trial examining the benefits of pemetrexed/ cisplatin chemotherapy combined with radiation followed by consolidation pemetrexed in patients with unresectable stage IIIA/B non-small-cell lung cancer. The rationale for the selection of the control arm is provided, and study design limitations are discussed. The primary outcome is survival, and secondary outcomes include progression-free survival, toxicities, and 1-, 2-, and 3-year survival rates. Radiation quality control is a key component of the trial.

Updated clinical information on multitargeted antifolates in lung cancer

Pemetrexed, a third-generation antifolate already indicated in combination with cisplatin for the systemic treatment of malignant pleural mesothelioma and, as a single agent, for the second-line treatment of non-small-cell lung cancer was in 2008 granted approval for histologically based first-line treatment by both the EMEA and FDA. Thymidylate synthase, the main molecular target of pemetrexed, has higher mRNA and protein expression in squamous- and small-cell lung cancer compared with adenocarcinoma. This differential expression might well molecularly explain the differential clinical activity of pemetrexed in the various histotypes of lung cancer, including the marginal activity in small-cell lung cancer. These hypothesis-generating findings are currently validated in prospective studies.

Phase II evaluation of pemetrexed in the treatment of recurrent or persistent platinum-resistant ovarian or primary peritoneal carcinoma: a study of the Gynecologic Oncology Group

PURPOSE

To estimate the antitumor activity of pemetrexed in patients with persistent or recurrent platinum-resistant epithelial ovarian or primary peritoneal cancer and to determine the nature and degree of toxicities.

PATIENTS AND METHODS

A phase II trial was conducted by the Gynecologic Oncology Group. Patients must have had cancer that had progressed on platinum-based primary chemotherapy or recurred within 6 months. Pemetrexed at a dose of 900 mg/m(2) was to be administered as an intravenous infusion over 10 minutes every 21 days. Dose delay and adjustment was permitted for toxicity. Treatment was continued until disease progression or unacceptable adverse effects.

RESULTS

From July 6, 2004, to August 23, 2006, 51 patients were entered. A total of 259 cycles (median, four; range one to 19 cycles) of pemetrexed were administered, with 40% of patients receiving six or more cycles. Overall, the treatment was well tolerated. More serious toxicities (grade 3 and 4) included neutropenia in 42%, leukopenia in 25%, anemia in 15%, and constitutional in 15% of patients. No treatment-related deaths were reported. One patient (2%) had a complete and nine patients (19%) had partial responses, with a median duration response of 8.4 months. Seventeen patients (35%) had stable disease for a median of 4.1 months. Eighteen patients (38%) had increasing disease. Three patients (6%) were not assessable. Median progression-free survival was 2.9 months, and overall survival was 11.4 months.

CONCLUSION

Pemetrexed has sufficient activity in the treatment of recurrent platinum-resistant ovarian cancer at the dose and schedule tested to warrant further investigation.

Pemetrexed, Carboplatin, and Concomitant Radiation followed by Surgery for Locally Advanced Esophageal Cancer: Results of a Planned Interim Toxicity Analysis of North Central Cancer Treatment Group Study N044E

PURPOSE

This brief report describes a planned, interim, 6-patient toxicity analysis that confirms the safety of pemetrexed, carboplatin, radiation with subsequent surgery, as prescribed in the North Central Cancer Treatment Group trial N044E, in patients with locally advanced esophageal cancer.

METHODS

Six patients with locally advanced, potentially resectable esophageal cancer received pemetrexed 500 mg/m(2) and carboplatin AUC = 6 on days 1 and 22 with 5040 centigray of concomitant radiation in 28 fractions over 5.5 weeks followed by esophagectomy as a prelude to a phase II multi-institutional trial.

RESULTS

Only 1 of the 6 patients experienced a grade 4 adverse event (neutropenia). This patient also experienced a grade 3 depression. Of the remaining 5 patients, three experienced at least one grade 3 adverse event (neutropenia, nausea/vomiting, and esophagitis). There were no deaths. Incidentally, one patient manifested a complete pathologic response, three a partial pathologic response, and one stable disease.

CONCLUSION

These preliminary observations on safety suggest that this regimen can be further studied in this clinical setting.

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.

The chemoradiation paradigm in head and neck cancer

In this article, we use the example of head and neck cancer to show how concurrent chemoradiotherapy is used to treat a cancer where locoregional control is central for treatment success. The advent of concurrent chemoradiation has significantly contributed to the curability of head and neck cancer, including locoregionally advanced disease. Preserving organ function and reducing toxic effects are increasingly the focus of clinical trials. We review the available chemoradiotherapy platforms used for head and neck cancer, with initial discussions focused on single-agent cytotoxic-based regimens. We then assess the literature on multiagent-based regimens and include a discussion of the integration of novel agents, such as EGFR inhibitors, and antiangiogenic drugs into treatment platforms. Although single-agent cisplatin-based chemoradiotherapy is still widely used as a standard therapy, we propose that evidence increasingly shows that multiagent-based chemoradiotherapy, and EGFR-inhibitor-based treatments, offer distinct advantages. We provide guidance for clinicians based on current clinical trial evidence on how to choose appropriate treatment platforms for their patients.