A prospective phase II study: High-dose pemetrexed as second-line chemotherapy in small-cell lung cancer

A phase II study of pembrolizumab and paclitaxel in patients with relapsed or refractory small-cell lung cancer

OBJECTIVE

Patients with etoposide/platinum-refractory extensive disease (ED) small-cell lung cancer (SCLC) have a dismal prognosis. We aimed to evaluate the efficacy and safety of pembrolizumab and paclitaxel combination therapy in these patients.

METHODS

In this multi-center, phase II study, ED-SCLC patients who showed progression after etoposide/platinum chemotherapy received paclitaxel 175 mg/m² every 3 weeks for up to six cycles. Pembrolizumab 200 mg was added from the second cycle and continued until disease progression or unacceptable toxicity. The primary endpoint was the objective response rate (ORR) and the secondary endpoints were progression-free survival (PFS), overall survival (OS), safety, and biomarker analyses including programmed death-ligand 1 (PD-L1) expression, next-generation sequencing, and flow cytometric analysis of peripheral blood cells.

RESULTS

Of the 26 patients enrolled, the confirmed ORR was 23.1% (95%CI: 6.9%-39.3%); complete response: 3.9%, confirmed partial response [PR]: 19.2%, stable disease: 57.7%, progressive disease: 7.7%, and not evaluable: 11.5%. Including 4 cases of unconfirmed PRs, 38.5% of patients were responding and the disease control rate was 80.7%. The median PFS and OS were 5.0 months (95% CI: 2.7-6.7) and 9.1 months (95% CI: 6.5-15.0), respectively. The grade 3 or 4 adverse events observed included febrile neutropenia (7.7%), neutropenia (7.7%), asthenia (7.7%), hyponatremia (7.7%), and type I diabetes (7.7%). Targeted gene sequencing identified no specific genetic alterations correlated with the treatment, except for theMET copy number gain (PFS 10.5 versus 3.4 months, p = 0.019).

CONCLUSIONS

Pembrolizumab and paclitaxel combination therapy showed a moderate activity with acceptable toxicity in patients with refractory ED-SCLC.

Treatment advances in small cell lung cancer (SCLC)

Small cell lung cancer (SCLC) is an aggressive tumor characterized by rapid doubling time and high propensity for early development of disseminated disease. Although most patients respond to initial therapy with a platinum doublet, the majority of those with limited stage and virtually all patients with metastatic disease eventually develop tumor progression for which there are limited treatment options. There have been no recent changes in the treatment of SCLC, with platinum plus etoposide and topotecan as the standard first-line and second-line respectively, neither showing survival benefit over the combination of cyclophosphamide, doxorubicin and vincristine, which was developed in the 1970s. More recently, a new understanding of the biology of SCLC has led to the development of novel drugs, of which the most promising are the immune checkpoint inhibitors and the antibody drug conjugate rovalpituzumab tesirine.

Hidden treasures in "ancient" microarrays: gene-expression portrays biology and potential resistance pathways of major lung cancer subtypes and normal tissue

Objective: Novel statistical methods and increasingly more accurate gene annotations can transform “old” biological data into a renewed source of knowledge with potential clinical relevance. Here, we provide an in silico proof-of-concept by extracting novel information from a high-quality mRNA expression dataset, originally published in 2001, using state-of-the-art bioinformatics approaches.

Methods: The dataset consists of histologically defined cases of lung adenocarcinoma (AD), squamous (SQ) cell carcinoma, small-cell lung cancer, carcinoid, metastasis (breast and colon AD), and normal lung specimens (203 samples in total). A battery of statistical tests was used for identifying differential gene expressions, diagnostic and prognostic genes, enriched gene ontologies, and signaling pathways.

Results: Our results showed that gene expressions faithfully recapitulate immunohistochemical subtype markers, as chromogranin A in carcinoids, cytokeratin 5, p63 in SQ, and TTF1 in non-squamous types. Moreover, biological information with putative clinical relevance was revealed as potentially novel diagnostic genes for each subtype with specificity 93–100% (AUC = 0.93–1.00). Cancer subtypes were characterized by (a) differential expression of treatment target genes as TYMS, HER2, and HER3 and (b) overrepresentation of treatment-related pathways like cell cycle, DNA repair, and ERBB pathways. The vascular smooth muscle contraction, leukocyte trans-endothelial migration, and actin cytoskeleton pathways were overexpressed in normal tissue.

Conclusion: Reanalysis of this public dataset displayed the known biological features of lung cancer subtypes and revealed novel pathways of potentially clinical importance. The findings also support our hypothesis that even old omics data of high quality can be a source of significant biological information when appropriate bioinformatics methods are used.

Associations between TS, TTF-1, FR-α, FPGS, and overall survival in patients with advanced non-small-cell lung cancer receiving pemetrexed plus carboplatin or gemcitabine plus carboplatin as first-line chemotherapy

INTRODUCTION

Pemetrexed is effective in the treatment of non-small-cell lung cancer, mainly in nonsquamous cell carcinomas. Inhibition of thymidylate synthase (TS) is considered the key mechanism of action. Folate receptor-α facilitates uptake of pemetrexed. Polyglutamation by folylpolyglutamate synthetase enhances activity and prolongs cellular retention of pemetrexed. Thyroid transcription factor-1 (TTF-1) is mainly positive in nonsquamous cell carcinoma and has been proposed as a marker for sensitivity to pemetrexed. The aim was to investigate associations between these biomarkers and survival in patients who participated in a phase III trial comparing pemetrexed plus carboplatin with gemcitabine plus carboplatin as first-line chemotherapy in advanced non-small-cell lung cancer (n = 436). In this study, there was no difference in overall survival between the two regimens.

METHODS

Formalin-fixed, paraffin-embedded biopsies were collected. Percentages of tumor cells positive and highly positive for the biomarkers were assessed using immunohistochemistry (IHC) and an IHC score was calculated (range, 0-200).

RESULTS

Two hundred thirty-six biopsies were analyzed (pemetrexed plus carboplatin: n = 114, gemcitabine plus carboplatin: n = 122). There was a significant difference in overall survival between those with TTF-1-positive and -negative tumors (10.4 versus 6.0 months; p < 0.001) and those with a low and a high TS IHC score (9.7 versus 6.2 months; p < 0.001). Folate receptor-α and folylpolyglutamate synthetase were not significant prognostic factors. In multivariate analyses adjusting for established prognostic characteristics, TS (p = 0.002) and TTF-1 (p = 0.003) remained significant. There were no differences in survival between the treatment arms depending on biomarker scores.

CONCLUSIONS

TTF-1 positivity and low TS level were associated with prolonged survival. The associations between the biomarkers and overall survival were similar for both chemotherapy regimens.

Relapsed small cell lung cancer: treatment options and latest developments

According to recent analyses, there was a modest yet significant improvement in median survival time and 5-year survival rate of limited stage small cell lung cancer (SCLC) in North America, Europe, Japan and other countries over the last 30 years. The median survival time of limited stage SCLC is 15-20 months and 5-year survival rate is 15% or less. In terms of extensive stage SCLC, a median survival time of 9.4-12.8 months and 2-year survival of 5.2-19.5% are still disappointing. Despite being highly sensitive to first-line chemotherapy and radiotherapy treatments, most patients with SCLC experience relapse within 2 years and die from systemic metastasis. While several clinical trials of cytotoxic chemotherapies and molecular targeting agents have been investigated in the treatment of relapsed SCLC, none showed a significant clinical activity to be able to exceed topotecan as second-line chemotherapy. There are problematic issues to address for relapsed SCLC, such as standardizing the treatment for third-line chemotherapy. Topotecan alone was the first approved therapy for second-line treatment for relapsed SCLC. Amrubicin is a promising drug and a variety of trials evaluating its efficacy have been carried out. Amrubicin has shown superiority to topotecan in a Japanese population, but was not superior in a study of western patients. There are some controversial issues for relapsed SCLC, such as treatment for older patients, third-line chemotherapy and efficacy of molecular targeting therapy. This article reviews current standard treatment, recent clinical trials and other topics on relapsed SCLC.

A phase II study of S-1 in relapsed small cell lung cancer

S-1 is a new oral fluoropyrimidine derivative designed to enhance anticancer activity and reduce gastrointestinal toxicity. This phase II trial aimed to evaluate S-1 in patients with relapsed small cell lung cancer (SCLC). SCLC patients who had experienced treatment failure with ≥1 prior chemotherapies were eligible. Patients were required to have an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-2 and adequate organ function. Treatment consisted of oral S-1 at 40 mg/m² twice/day for 28 days every 6 weeks. Twenty-six patients were enrolled, 85% of whom were males. The median age was 68 years (range, 33-79) and 81% of the patients had a performance status of 0-1, and 46% of the patients had relapse-sensitive SCLC. An objective response was obtained in only 1 patient (3.8%), and the median progression-free survival (PFS) was 1.1 months. The median overall survival was 5.3 months, and the 1-year survival rate was 23%. The most common grade 3/4 toxicities included neutropenia (7.7%), leukopenia (7.7%), anemia (7.7%), hyponatremia (7.7%), rash (7.7%), infection (7.7%) and diarrhoea (3.8%). None of the patients developed febrile neutropenia and no deaths were attributed to treatment. In conclusion, S-1 has minimal single-agent activity in relapsed SCLC.

A systematic analysis of efficacy of second-line chemotherapy in sensitive and refractory small-cell lung cancer

INTRODUCTION

Small-cell lung cancer (SCLC) patients unresponsive or relapsing within 90 days after frontline chemotherapy have poor prognosis and are treated with regimens different from the first-line regimen. Potential differences in the efficacy of second-line therapy for refractory and sensitive SCLC have not been well studied.

METHODS

Studies that enrolled sensitive and refractory (relapse < 90 days or > 90 days) SCLC patients for second-line therapy were identified using electronic databases (MEDLINE, EMBASE, and Cochrane library), and meeting abstracts databases. A systematic analysis was conducted using Comprehensive Meta Analysis (version 2.2.048) software to calculate the odds ratio of response and 95% confidence interval. Median overall survival time for sensitive and resistant SCLC patients was compared by two-sided Student's t test. We tested for significant heterogeneity by Cochran's chi-square test and I-square index.

RESULTS

Twenty-one studies published between 1984 and 2011 were eligible for this analysis with a total of 1692 patients enrolled; 912 with sensitive and 780 with refractory SCLC. The overall response rate was 17.9% with a higher response rate of 27.7% (range, 0%-77%) for sensitive SCLC versus 14.8% (range, 0%-70%) for refractory patients; p=0.0001. Pooled overall odds ratio of response was 2.235 (95% confidence interval: 1.518-3.291; p=0.001) favoring patients with sensitive disease. Median overall survival time was 6.7 months with a weighted survival of 7.7 and 5.4 months for sensitive and refractory SCLC, respectively (p = 0.0035).

CONCLUSIONS

Refractory SCLC patients derive modest clinical benefit from second-line chemotherapy. However, response and survival outcomes are superior with chemosensitive disease.

Update on new drugs in small cell lung cancer

INTRODUCTION

Small cell lung cancer (SCLC) will account for 25,000 to 32,000 new lung cancer cases in the USA in 2010. Current treatmenta pproaches include platinum-based chemotherapy and etoposide with or without radiation therapy depending on stage and performance status. Five-year survival is approximately 25% for patients with limited stage disease and 1 -- 2% for patients with extensive stage disease and has noti mproved in almost two decades.

AREAS COVERED

This article reviews the results of recent clinical trials that have evaluated targeted agents and novel cytotoxic agents alone or in combination with standard chemotherapy in the treatment of patients with SCLC.

EXPERT OPINION

The lack of a targeted approach to the treatment of patients with SCLC has led investigators to evaluate a multitude of agents with overwhelmingly negative results. A more systematic approach to clinical trials in patients is needed to improve outcomes for patients with this disease.

Review of the management of relapsed small-cell lung cancer with amrubicin hydrochloride

Lung cancer is the leading cause of cancer death, and approximately 15% of all lung cancer patients have small-cell lung cancer (SCLC). Although second-line chemotherapy can produce tumor regression, the prognosis is poor. Amrubicin hydrochloride (AMR) is a synthetic anthracycline anticancer agent and a potent topoisomerase II inhibitor. Here, we discuss the features of SCLC, the chemistry, pharmacokinetics, and pharmacodynamics of AMR, the results of in vitro and in vivo studies, and the efficacy and safety of AMR monotherapy and combination therapy in clinical trials. With its predictable and manageable toxicities, AMR is one of the most attractive agents for the treatment of chemotherapy-sensitive and -refractory relapsed SCLC. Numerous studies are ongoing to define the applicability of AMR therapy for patients with SCLC. These clinical trials, including phase III studies, will clarify the status of AMR in the treatment of SCLC.

Thymidylate synthase (TS) gene expression in primary lung cancer patients: a large-scale study in Japanese population

BACKGROUND

Previous small-sized studies showed lower thymidylate synthase (TS) expression in adenocarcinoma of the lung, which may explain higher antitumor activity of TS-inhibiting agents such as pemetrexed.

PATIENTS AND METHODS

To quantitatively measure TS gene expression in a large-scale Japanese population (n = 2621) with primary lung cancer, laser-captured microdissected sections were cut from primary tumors, surrounding normal lung tissues and involved nodes.

RESULTS

TS gene expression level in primary tumor was significantly higher than that in normal lung tissue (mean TS/β-actin, 3.4 and 1.0, respectively; P < 0.01), and TS gene expression level was further higher in involved node (mean TS/β-actin, 7.7; P < 0.01). Analyses of TS gene expression levels in primary tumor according to histologic cell type revealed that small-cell carcinoma showed highest TS expression (mean TS/β-actin, 13.8) and that squamous cell carcinoma showed higher TS expression as compared with adenocarcinoma (mean TS/β-actin, 4.3 and 2.3, respectively; P < 0.01); TS gene expression was significantly increased along with a decrease in the grade of tumor cell differentiation. There was no significant difference in TS gene expression according to any other patient characteristics including tumor progression.

CONCLUSION

Lower TS expression in adenocarcinoma of the lung was confirmed in a large-scale study.

Treatment options for small cell lung cancer - do we have more choice?

Small cell lung cancer (SCLC) is a significant health problem worldwide because of its high propensity for relapse. This review discusses existing and future therapies for the treatment of SCLC.

Phase III study of pemetrexed plus carboplatin compared with etoposide plus carboplatin in chemotherapy-naive patients with extensive-stage small-cell lung cancer

PURPOSE

Following a phase II trial in which pemetrexed-platinum demonstrated similar activity to that of historical etoposide-platinum controls, a phase III study was conducted to compare pemetrexed-carboplatin with etoposide-carboplatin for the treatment of extensive-stage small-cell lung cancer (ES-SCLC).

PATIENTS AND METHODS

Chemotherapy-naive patients with ES-SCLC and an Eastern Cooperative Oncology Group performance status of zero to 2 were randomly assigned to receive pemetrexed-carboplatin (pemetrexed 500 mg/m(2) on day 1; carboplatin at area under the serum concentration-time curve [AUC] 5 on day 1) or etoposide-carboplatin (etoposide 100 mg/m(2) on days 1 through 3; carboplatin AUC 5 on day 1) every 3 weeks for up to six cycles. The primary objective of the study was noninferiority of pemetrexed-carboplatin overall survival with a 15% margin.

RESULTS

Accrual was terminated with 908 of 1,820 patients enrolled after results of a planned interim analysis. In the final analysis, pemetrexed-carboplatin was inferior to etoposide-carboplatin for overall survival (median, 8.1 v 10.6 months; hazard ratio [HR],1.56; 95% CI, 1.27 to 1.92; log-rank P < .01) and progression-free survival (median, 3.8 v 5.4 months; HR, 1.85; 95% CI, 1.58 to 2.17; log-rank P < .01). Objective response rates were also significantly lower for pemetrexed-carboplatin (31% v 52%; P < .001). Pemetrexed-carboplatin had lower grade 3 to 4 neutropenia, febrile neutropenia, and leukopenia than etoposide-carboplatin; grade 3 to 4 thrombocytopenia was comparable between arms and anemia was higher in the pemetrexed-carboplatin arm.

CONCLUSION

Pemetrexed-carboplatin is inferior for the treatment of ES-SCLC. Planned translational research and pharmacogenomic analyses of tumor and blood samples may help explain the study results and provide insight into new treatment strategies.

Pemetrexed in the treatment of advanced non-squamous lung cancer

Pemetrexed, a new cytotoxic agent, is a potent inhibitor of thymidylate synthase and other folate-dependent enzymes. Firstly, pemetrexed was approved in combination with cisplatin for the treatment of malignant pleural mesothelioma. Successively, it has been studied, as single-agent, in phase II and III trials for second-line therapy of non-small cell lung cancer (NSCLC). Based on these results, pemetrexed has been registered for the treatment of recurrent NSCLC. The next step was to test pemetrexed plus cisplatin versus gemcitabine plus cisplatin, as first-line therapy in advanced NSCLC patients, in a phase III, non-inferiority, randomized trial. This trial reported the pemetrexed plus cisplatin regimen to be not inferior, in terms of activity and efficacy, to the control arm but statistically better tolerated. The role of pemetrexed as maintenance therapy after first-line therapy for advanced NSCLC is currently being evaluated into a phase III trial. The consistency of the results of these recent studies has identified a predictive effect of NSCLC non-squamous histology for pemetrexed. To date, pemetrexed is registered, at the dose of 500 mg/m(2) on day 1 of a 3-week schedule, in combination with cisplatin, for first-line therapy and, as single-agent, for second-line treatment of patients with non-squamous NSCLC.This review shows the latest and indicates the future developments of pemetrexed in the treatment of advanced NSCLC patients.

Tailoring treatment of nonsmall cell lung cancer by tissue type: role of pemetrexed

Pemetrexed (ALIMTA, LY231514, MTA) is a novel multitargeted antifolate that is currently approved for the treatment of metastatic nonsmall cell lung cancer (NSCLC). Recent evidence reveals that the drug's efficacy is limited to nonsquamous lung cancer histology. As we further understand the drug's mechanisms of action, new genomic and proteomic evidence is shedding light on why some patients respond while others do not. The first goal of this review is to briefly review pemetrexed's mechanism of action, resistance patterns, toxicity profile, and pharmacokinetics. We will also review the clinical trials that led to its use in NSCLC, with special attention to data showing that pemetrexed has greater efficacy in nonsquamous histologies of NSCLC. Furthermore, we will discuss the hypotheses for the genomic and proteomic basis for this variation in efficacy. Finally, we will report the future directions for pemetrexed as a personalized agent for nonsquamous NSCLC.

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.

The differential efficacy of pemetrexed according to NSCLC histology: a review of two Phase III studies

BACKGROUND

Recent studies of pemetrexed have identified a predictive role for non-small cell lung cancer (NSCLC) histology. We further reviewed the differential efficacy of pemetrexed according to histology in two large, phase III NSCLC trials.

METHODS

One study tested pemetrexed versus docetaxel in previously treated patients (n = 571) and the other tested cisplatin plus pemetrexed versus cisplatin plus gemcitabine in chemotherapy-naive patients (n = 1,725) with advanced NSCLC. Cox proportional hazard models were used to test for covariate-adjusted treatment-by-histology interactions (THIs) for overall survival (OS) and progression-free survival (PFS). For each histologic subgroup, the Kaplan-Meier method was used to estimate unadjusted within-arm medians, and Cox models were used to estimate covariate-adjusted between-arm hazard ratios (HRs).

RESULTS

In both studies, treatment arms were well balanced for histology. THIs were statistically significant (p < .005) for both OS and PFS. Nonsquamous patients treated with pemetrexed-based therapy experienced longer survival than the comparators (HR, 0.78 and 0.84, respectively), whereas squamous patients had shorter survival (HR, 1.56 and 1.23, respectively). Whereas the efficacy of pemetrexed regimens differed according to histology, it did not differ for docetaxel or for cisplatin plus gemcitabine. Pemetrexed was well tolerated across histologic groups.

CONCLUSIONS

The consistency of these results across studies confirms the predictive effect of histology for pemetrexed and the survival advantage for pemetrexed in patients with nonsquamous histology. These analyses suggest pemetrexed should not be recommended for the treatment of squamous cell carcinoma, but, because of efficacy and safety advantages, pemetrexed may be preferable to other agents for treatment of patients with nonsquamous NSCLC.