Pemetrexed in Relapsed Small-Cell Lung Cancer and the Impact of Shortened Vitamin Supplementation Lead-In Time: Results of a Phase II Trial

A phase II study of antiangiogenic therapy (Apatinib) plus chemotherapy as second-line treatment in advanced small cell lung cancer

INTRODUCTION

Currently, only a few options are available for the treatment of patients with small-cell lung cancer (SCLC) after the failure of first-line platinum-based chemotherapy. The present study aimed to evaluate the efficacy and safety of apatinib plus chemotherapy for second-line treatment of advanced SCLC.

PATIENTS AND METHODS

This prospective clinical trial recruited patients treated with apatinib plus second-line chemotherapy until disease progression or intolerable toxicity. Logrank test power analysis was used for calculating samples. The primary endpoint was progression-free survival (PFS), and the secondary endpoints were objective response rate (ORR), disease control rate (DCR), overall survival (OS), and safety.

RESULTS

A total of 29/31 enrolled patients were available for response evaluation until October 2019. The ORR and DCR were 27.59% (8/29) and 96.55% (28/29), respectively. The median PFS and OS were 7.36 months and 14.16 months, respectively, indicating better efficacy compared with the standard second-line chemotherapies. The most common adverse events (AEs) were neutropenia (41.94%, 13/31), followed by leucopenia (35.48%, 11/31) and thrombocytopenia (25.81%, 8/31). The grade 3-4 AEs occurred in 12 (38.71%) patients, of which neutropenia (19.35%, 6/31), leucopenia (9.68%, 3/31), and proteinuria (6.45%, 2/31) were most common. Patients receiving an initial dose of apatinib 250 mg had a better tolerance.

CONCLUSION

Antiangiogenic therapy plus chemotherapy had encouraging efficacy in advanced SCLC patients, which provides an insight into the current status of second-line therapy in SCLC.

Safety of Same-Day Vitamin B12 Supplementation in Patients Receiving Pemetrexed for the Treatment of Non-Small-Cell Lung Cancer or Pleural Mesothelioma: A Retrospective Analysis

BACKGROUND

Pemetrexed is a folate analog inhibitor for the treatment of non-small-cell lung cancer (NSCLC) and malignant pleural mesothelioma. Folic acid and vitamin B12 supplementation before initiating pemetrexed is necessary because of high rates of cytopenias without supplementation. However, the timing of supplementation has not been thoroughly investigated.

PATIENTS AND METHODS

This was a single-center, retrospective study investigating patients receiving pemetrexed from January 1, 2012, to June 30, 2015, who received same-day vitamin B12 supplementation versus ≥ 1 day before pemetrexed. The objective was to evaluate safety outcomes in patients who received vitamin B12 on the same day as pemetrexed (group A) versus vitamin B12 ≥ 1 day (group B) before pemetrexed.

RESULTS

Two hundred eighty-one patients met the inclusion criteria: 137 patients in group A (same-day administration of vitamin B12) and 144 patients in group B (median time of vitamin B12 administration before pemetrexed, 7 days; range, 1-42 days). Mean changes in hematologic indices from cycle (C) 1 to C2 or C2 to C3 did not differ significantly between groups. There were no significant differences in clinical events between C1 and C2 or C2 and C3 requiring supportive care. There was a significant difference noted in treatment delay in C3 [28/114 (24.6%) group A vs. 14/118 (11.9%) group B, P = .0164]. In group A, significant predictors of delay in C3 were baseline hemoglobin (mean 13.3 g/dL vs. 12.4 g/dL, P = .0137) and ANC (mean 6 × 10⁹/L vs. 5 × 10⁹/L, P = .0003).

CONCLUSION

Same-day vitamin B12 and pemetrexed administration is a safe practice in NSCLC and malignant pleural mesothelioma patients.

A prospective study of shortened vitamin supplementation prior to cisplatin-pemetrexed therapy for non-small cell lung cancer

BACKGROUND

Prior supplementation with folic acid and vitamin B12 is required to reduce pemetrexed therapy toxicity; the recommended lead-in time is at least 7 days. On the basis of previous pharmacokinetic and clinical studies, we hypothesized that the lead-in time could be shortened to 24 hours, enabling earlier commencement of standard chemotherapy; thus, we planned the first prospective trial of this regimen.

METHODS

Patients with advanced nonsquamous non-small cell lung cancer who had not previously received cytotoxic chemotherapy were enrolled. After measurement of homocysteine concentrations, the patients received 1,000 μg of vitamin B12 by intramuscular injection and began taking 350-500 μg of oral folic acid daily. Starting 24-48 hours after the vitamin B12 injection, the patients received intravenous 500 mg/m(2) pemetrexed and 75 mg/m(2) cisplatin for 4 cycles at 3 weekly intervals. The primary endpoint was the proportion of patients who developed neutropenia grade ≥3.

RESULTS

Thirty patients received chemotherapy starting within 48 hours of the vitamin B12 injection. No treatment-related deaths or grade 4 toxicity occurred. Neutropenia grade ≥3, other laboratory toxicities grade ≥3, and nonlaboratory toxicities grade ≥3 occurred in 6.7%, 13%, and 13% of patients, respectively. The baseline homocysteine concentrations were not higher in patients with grade ≥3 toxicities than in the remainder of the cohort (mean values, 8.6 and 10.7 μmol/L, respectively). The response rate to chemotherapy was 43%.

CONCLUSION

The shortened vitamin supplementation was well tolerated and retained antitumor efficacy. Analysis of baseline homocysteine concentrations confirmed the efficacy of short-term vitamin supplementation.

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.

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.

Chemotherapy advances in small-cell lung cancer

Although chemotherapeutic advances have recently been heralded in lung adenocarcinomas, such success with small-cell lung cancer (SCLC) has been ominously absent. Indeed, the dismal outlook of this disease is exemplified by the failure of any significant advances in first line therapy since the introduction of the current standard platinum-etoposide doublet over 30 years ago. Moreover, such sluggish progress is compounded by the dearth of FDA-approved agents for patients with relapsed disease. However, over the past decade, novel formulations of drug classes commonly used in SCLC (e.g. topoisomerase inhibitors, anthracyclines, alkylating and platinum agents) are emerging as potential alternatives that could effectively add to the armamentarium of agents currently at our disposal. This review is introduced with an overview on the historical development of chemotherapeutic regimens used in this disease and followed by the recent encouraging advances witnessed in clinical trials with drugs such as amrubicin and belotecan which are forging new horizons for future treatment algorithms.

Uracil-DNA glycosylase expression determines human lung cancer cell sensitivity to pemetrexed

Uracil misincorporation into DNA is a consequence of pemetrexed inhibition of thymidylate synthase. The base excision repair (BER) enzyme uracil-DNA glycosylase (UNG) is the major glycosylase responsible for removal of misincorporated uracil. We previously illustrated hypersensitivity to pemetrexed in UNG(-/-) human colon cancer cells. Here, we examined the relationship between UNG expression and pemetrexed sensitivity in human lung cancer. We observed a spectrum of UNG expression in human lung cancer cells. Higher levels of UNG are associated with pemetrexed resistance and are present in cell lines derived from pemetrexed-resistant histologic subtypes (small cell and squamous cell carcinoma). Acute pemetrexed exposure induces UNG protein and mRNA, consistent with upregulation of uracil-DNA repair machinery. Chronic exposure of H1299 adenocarcinoma cells to increasing pemetrexed concentrations established drug-resistant sublines. Significant induction of UNG protein confirmed upregulation of BER as a feature of acquired pemetrexed resistance. Cotreatment with the BER inhibitor methoxyamine overrides pemetrexed resistance in chronically exposed cells, underscoring the use of BER-directed therapeutics to offset acquired drug resistance. Expression of UNG-directed siRNA and shRNA enhanced sensitivity in A549 and H1975 cells, and in drug-resistant sublines, confirming that UNG upregulation is protective. In human lung cancer, UNG deficiency is associated with pemetrexed-induced retention of uracil in DNA that destabilizes DNA replication forks resulting in DNA double-strand breaks and cell death. Thus, in experimental models, UNG is a critical mediator of pemetrexed sensitivity that warrants evaluation to determine clinical value.

Chemotherapy for pulmonary large cell neuroendocrine carcinoma: similar to that for small cell lung cancer or non-small cell lung cancer?

BACKGROUND

There is controversy regarding palliative chemotherapy for large cell neuroendocrine carcinoma (LCNEC). We evaluated whether advanced LCNEC should be treated similarly to small cell lung cancer (SCLC) or non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

The clinical reports and tumor specimens of 45 consecutive patients who were diagnosed with advanced LCNEC were reviewed. They were divided into SCLC (n=11) and NSCLC regimen groups (n=34) according to first-line chemotherapeutic regimens.

RESULTS

Most patients were male (96%) and smokers (93%) with a median age of 64 years. Neuroendocrine differentiation was established in 42 (93%) tumors by immunohistochemical analyses. Regarding the efficacy of first-line chemotherapy in the SCLC and NSCLC regimen groups, the response rates were 73% and 50% (P=0.19), and the median progression-free survival times were 6.1 and 4.9 months (P=0.41), respectively. The difference in overall survival between the two treatment groups was 7.3 months (16.5 vs. 9.2 months, P=0.10). There was also a considerable difference in the type and efficacy of salvage chemotherapeutic regimens between the two groups: salvage regimens with irinotecan, platinum, or taxanes were commonly used with relatively high objective responses in the SCLC regimen group, whereas frequently used agents in the NSCLC regimen group such as pemetrexed, gefitinib, or erlotinib were associated with no objective response.

CONCLUSION

Regarding palliative chemotherapy for advanced LCNEC, treatment similar to SCLC is more appropriate than NSCLC.

Current management of small cell lung cancer

Confined to one side of the chest, limited stage small cell lung cancer is treated with a combination of chemotherapy and radiotherapy, yet has a long-term survival rate of only 15%. Extensive stage disease has initial response rates to chemotherapy exceeding 70%. However, the disease almost invariably progresses and becomes fatal. Many recent clinical trials have failed to show superiority of newer chemotherapeutics or targeted therapies compared with the standard chemotherapy backbone of platinum plus etoposide. Numerous promising targeted therapies and other agents are still in development.

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.

New advances in the second-line treatment of small cell lung cancer

Lung cancer is the leading cause of cancer-related death in the U.K., with small cell histology accounting for 15%-20% of cases. Small cell lung cancer (SCLC) is initially a chemosensitive disease, but relapse is common, and in this group of patients it remains a rapidly lethal disease with a particularly poor prognosis. The choice of second-line chemotherapy for patients with relapsed SCLC has been an area of difficulty for oncologists, and until recently there was no randomized evidence for its use over best supportive care (BSC). Topotecan is currently the only drug licensed in Europe and the U.S. for this indication, having been shown in a phase III trial to lead to longer overall survival and better quality of life than with BSC. In this article, we review the current evidence for the use of second-line cytotoxic therapy and also the emerging role of novel agents and targeted therapies in this setting. In particular, we explore the role of the Bcl-2 protein family, which are key regulators of mitochondrial apoptosis and are implicated in resistance to anticancer therapies. SCLC overexpresses antiapoptotic members of the Bcl-2 family in approximately 80% of cases. Several Bcl-2 inhibitors, including obatoclax, are currently entering clinical trials in SCLC and are an exciting area of drug development in the relapsed setting.

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.