Clinical activity of pemetrexed: a multitargeted antifolate anticancer agent

Vitamin B12-Multifaceted In Vivo Functions and In Vitro Applications

Vitamin B12 plays a key role in DNA stability. Research indicates that vitamin B12 deficiency leads to indirect DNA damage, and vitamin B12 supplementation may reverse this effect. Vitamin B12 acts as a cofactor for enzymes such as methionine synthase and methylmalonyl-CoA mutase, which are involved in DNA methylation and nucleotide synthesis. These processes are essential for DNA replication and transcription, and any impairment can result in genetic instability. In addition, vitamin B12 has antioxidant properties that help protect DNA from damage caused by reactive oxygen species. This protection is achieved by scavenging free radicals and reducing oxidative stress. In addition to their protective functions, cobalamins can also generate DNA-damaging radicals in vitro that can be useful in scientific research. Research is also being conducted on the use of vitamin B12 in medicine as vectors for xenobiotics. In summary, vitamin B12 is an essential micronutrient that plays a vital role in DNA stability. It acts as a cofactor for enzymes involved in the synthesis of nucleotides, has antioxidant properties and has potential value as a generator of DNA-damaging radicals and drug transporters.

Promoter polymorphisms of TOP2A and ERCC1 genes as predictive factors for chemotherapy in non-small cell lung cancer patients

Background

Topoisomerase 2‐alpha (TOP2A) is an enzyme that controls topologic changes in DNA during transcription and replication. ERCC1 is an enzyme that takes part in DNA repair processes. The purpose of this study was to assess the predictive role of particular single nucleotide polymorphisms (SNPs) in the promoter regions of TOP2A and ERCC1 genes in non‐small cell lung cancer patients (NSCLC) treated with chemotherapy.

Materials and methods

We enrolled 113 NSCLC patients treated in the first line with platinum‐based chemotherapy. Effectiveness was available for 71 patients. DNA was isolated from whole blood using the Qiamp DNA Blood Mini kit (Qiagen). We examined five SNPs: rs11615 (ERCC1), rs3212986 (ERCC1), rs13695 (TOP2A), rs34300454 (TOP2A), rs11540720 (TOP2A). Quantitative PCR using the TaqMan probe (ThermoFisher) was performed on a Eco Illumina Real‐Time PCR system device (Illumina Inc).

Results

Patients with the A/A genotype in rs11615 of the ERCC1 gene had significantly longer median progression free survival (PFS) (8.5 months; P = .0088). Patients with the C/C genotype in rs3212986 of the ERCC1 gene had longer median PFS (7 months; P = .05). Patients with the C/C genotype in rs34300454 of TOP2A gene had significantly higher median PFS (7.5 months; P = .0029). Carriers of the C/C genotype in rs34300454 of the TOP2A gene had significantly longer median OS (15.5 months; P = .0017). Patients with the A/A genotype in rs11615 of the ERCC1 gene had significantly higher risk of neutropenia (P = .0133).

Conclusions

Polymorphisms of the TOP2A and ERCC1 genes may be a predictive factor of toxicities and survival for chemotherapy in NSCLC patients.

Safety profiles of first-line therapies for metastatic non-squamous non-small-cell lung cancer

INTRODUCTION

Lung cancer still represents the leading cause of death for cancer. About the 70% of diagnosis are in advanced-stage. Non-small-cell lung cancer (NSCLC) represents the 85% of all diagnosed lung cancers and non-squamous histology represents the 40% of all NSCLC. First-line therapies increase survival, control symptoms and improve quality of life, compared with best supportive care. It is crucial to choose a treatment with a low impact on patient's life considering the related toxicities.

AREAS COVERED

Adverse events (AEs) of first-line therapies for non-squamous NSCLC are here reviewed and discussed, from evidences in clinical trials conducting to drugs approval.

EXPERT OPINION

For advanced disease, palliation and preserving patients QoL are still the primary goal of treatment. Therefore, differing toxicity profiles are often a deciding factor in first-line and also maintenance setting for non-squamous NSCLC. Special attention is necessary to renal function and drugs' nephrotoxicity. Moreover, it is to consider the specific AEs of drugs classes: hypertension, bleeding, and proteinuria, for anti-VEGF therapy; skin toxicity, diarrhea, interstitial lung disease for TKIs; vision disorders, and hepatotoxicity for ALK-inhibitor. It is important to select patients for a treatment on the basis of their comorbidities and the presence of risk factors.

Thymidylate Synthase as a Predictive Biomarker for Pemetrexed Response in NSCLC

In recent years, major strides in cancer research have made it possible to select personalized chemotherapy recommendations based on an individual patient's tumor biology. The prognostic and/or predictive ability of biomarkers seeks to tailor the use of targeted chemotherapy and can result in improved clinical outcomes with reduced toxicity. A proliferation of new technology and pharmacotherapeutics in the setting of current FDA Clinical Laboratory Improvement Amendment (CLIA) standards has resulted in a recent surge in direct-to-physician biomarker tests. However, in the absence of clinical validation, there is the concern that the biomarkers may be utilized prematurely, resulting in improper chemotherapy selection and patient harm. Thymidylate synthase (TS) has been marketed as a predictive biomarker for the use of pemetrexed in NSCLC. We will examine the evidence behind the use of TS as a predictive biomarker to predict response to pemetrexed in NSCLC. At this time, the evidence does not currently support using TS assays to guide chemotherapy selection outside of a clinical research protocol.

Inhaled lipid cisplatin (ILC) in the treatment of patients with relapsed/progressive osteosarcoma metastatic to the lung

BACKGROUND

Osteosarcoma treatment failure is most often from the inability to control metastatic disease in the lungs. Encapsulating cisplatin within lipid complexes and delivering the agent via inhalation targets lung metastases with minimal systemic exposure. An open-label, phase Ib/IIa study was performed to characterize the safety and efficacy of inhaled lipid cisplatin (ILC) in recurrent osteosarcoma patients who only had pulmonary metastases.

PROCEDURE

ILC was administered via nebulizer every 2 weeks (=1 cycle). Response was evaluated radiographically every 2 cycles. Cisplatin levels were measured in patients. When possible, metastasectomy was undertaken in patients after 2 cycles.

RESULTS

Nineteen patients were treated. No patients experienced hematologic toxicity, nephrotoxicity or ototoxicity. Nausea/vomiting (≥grade 3) was attributed to study drug in one patient. Respiratory symptoms were observed in 13/19 patients with only one patient experiencing a ≥grade 3 respiratory symptom (not related to study drug). Systemic cisplatin exposure was minimal. Eleven patients had bulky disease, and all progressed prior to cycle 7. Eight patients had all lesions ≤2 cm. One patient had a sustained partial response. An additional two patients had stable disease after 2 cycles, underwent metastasectomy, and remained free from pulmonary recurrence 1 year after initiation of therapy.

CONCLUSIONS

ILC is well tolerated in heavily treated osteosarcoma patients and did not appear to have the typical toxicities associated with intravenous cisplatin. Three of eight patients with less bulky disease had sustained benefit. Further study of ILC is warranted.

Adaptation of a chemosensitivity assay to accurately assess pemetrexed in ex vivo cultures of lung cancer

PURPOSE

Pemetrexed is the only FDA approved treatment for mesothelioma and is a second line agent for treatment of non-small cell lung carcinoma (NSCLC). Pemetrexed is inhibited by folate and its analogs, which are components of many culture media, making it challenging to study pemetrexed in vitro. In order to accurately evaluate pemetrexed's effects in vitro, the protocol for a standard chemosensitivity assay, the ChemoFx drug response marker, had to be modified.

EXPERIMENTAL DESIGN

Novel rinse and media change steps were assessed and then added to the assay protocol in order to observe pemetrexed activity. The intraday and interday stability of pemetrexed were also established under the adapted protocol. Then, the modified protocol was used to examine pemetrexed in 65 ex vivo lung cancer specimens.

RESULTS

Substituting 5% RPMI + EGF for BEGM allowed pemetrexed to exert its anticancer activity in the ChemoFx DRM. ChemoFx classified 6.2% of the lung specimens as responsive, 9.2% as intermediate responsive and 84.6% as non-responsive to pemetrexed.

CONCLUSIONS

Adapting the ChemoFx protocol allowed for the accurate evaluation of pemetrexed anticancer activity in ex vivo lung specimens. ChemoFx evaluation may provide an indication of a patient's clinical response to the drug prior to pemetrexed treatment. Having this information when treatment options are being considered could avoid wasted time, unnecessary costs and needless side effects that are the result of an inappropriate chemotherapy regimen.

A randomized, phase 2 study comparing pemetrexed plus best supportive care versus best supportive care as maintenance therapy after first-line treatment with pemetrexed and cisplatin for advanced, non-squamous, non-small cell lung cancer

BACKGROUND

Maintenance therapy for non-small cell lung cancer (NSCLC) aims to extend disease control after first-line chemotherapy with active and well-tolerated agents. The utility of continuation maintenance therapy requires further research.

METHODS

This multicenter, randomized, phase 2 study compared continuation maintenance therapy with pemetrexed (500 mg/m2 every 21 days) and best supportive care (BSC) versus BSC alone in patients with advanced, non-squamous NSCLC who had not progressed after 4 cycles of induction chemotherapy with pemetrexed (500 mg/m2) and cisplatin (75 mg/m2). The primary endpoint was progression-free survival (PFS) from randomization, was analyzed using a Cox model, stratified for the tumor response at the end of induction therapy, at a one-sided alpha of 0.2. Secondary endpoints: response and disease control rates, overall survival (OS), one year survival rates, and treatment-emergent adverse events (TEAEs).

RESULTS

A total of 106 patients commenced induction therapy, of whom 55 patients were randomized to maintenance pemetrexed/BSC (n = 28) or BSC (n = 27). Although the median PFS time for maintenance phase for both arms was 3.2 months, the one-sided p-value for the PFS HR comparison was less than the prespecified limit of 0.2 (HR = 0.76, two-sided 95% confidence interval [CI]: 0.42 to 1.37; one-sided p-value = 0.1815), indicating that PFS was sufficiently long in the pemetrexed/BSC arm to warrant further investigation. Similar PFS results were observed for the overall study period (induction plus maintenance) and when the PFS analysis was adjusted for sex, baseline disease stage, and the ECOG PS prior to randomization. The median OS for the maintenance phase was 12.2 months (95%CI: 5.6 to 20.6) for the pemetrexed/BSC arm and 11.8 months (95% CI: 6.3 to 25.6) for BSC arm. The one-year survival probabilities were similar for both arms for the maintenance phase and the overall study period. Both the induction and continuation maintenance therapies were generally well-tolerated, and similar proportion of patients in each arm experienced at least 1 grade 3/4 TEAE (pemetrexed/BSC, 17.9%; BSC, 18.5%).

CONCLUSIONS

Continuation pemetrexed maintenance therapy resulted in promising PFS with an acceptable safety profile in a Middle Eastern population with advanced non-squamous NSCLC and is worthy of further investigation.

TRIAL REGISTRATION

NCT00606021.

Schedule-dependent cytotoxic synergism of pemetrexed and erlotinib in BXPC-3 and PANC-1 human pancreatic cancer cells

Previous studies have shown that both pemetrexed, a cytotoxic drug, and erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), inhibit the cell growth of pancreatic cancer cells. However, whether they exert a synergistic antitumor effect on pancreatic cancer cells remains unknown. The present study aimed to assess the synergistic effect of erlotinib in combination with pemetrexed using different sequential administration schedules on the proliferation of human pancreatic cancer BXPC-3 and PANC-1 cells and to probe its cellular mechanism. The EGFR and K-ras gene mutation status was examined by quantitative PCR high-resolution melting (qPCR-HRM) analysis. BXPC-3 and PANC-1 cells were incubated with pemetrexed and erlotinib using different administration schedules. MTT assay was used to determine cytotoxicity, and cell cycle distribution was determined by flow cytometry. The expression and phosphorylation of EGFR, HER3, AKT and MET were determined using Western blotting. Both pemetrexed and erlotinib inhibited the proliferation of BXPC-3 and PANC-1 cells in a dose- and time-dependent manner in vitro. Synergistic effects on cell proliferation were observed when pemetrexed was used in combination with erlotinib. The degree of the synergistic effects depended on the administration sequence, which was most obvious when erlotinib was sequentially administered at 24-h interval following pemetrexed. Cell cycle studies revealed that pemetrexed induced S arrest and erlotinib induced G(0)/G(1) arrest. The sequential administration of erlotinib following pemetrexed induced S arrest. Western blot analyses showed that pemetrexed increased and erlotinib decreased the phosphorylation of EGFR, HER3 and AKT, respectively. However, both pemetrexed and erlotinib exerted no significant effects on the phosphorylation of c-MET. The phosphorylation of EGFR, HER3 and AKT was significantly suppressed by scheduled incubation with pemetrexed followed by erlotinib, but not by concomitant or sequential incubation with erlotinib followed by pemetrexed. In summary, our results demonstrated that the combined use of erlotinib and pemetrexed exhibited a strong synergism in BXPC-3 and PANC-1 cells. The inhibitory effects were strongest after sequential administration of pemetrexed followed by erlotinib. The synergistic effects may be related to activation of the EGFR/HER3/AKT pathway induced by pemetrexed.

Valproate, in combination with pemetrexed and cisplatin, provides additional efficacy to the treatment of malignant mesothelioma

PURPOSE

Present chemotherapeutic regimens are marginally efficient in tumor cells being particularly resistant to radiotherapy and/or chemotherapy. We hypothesized that unresponsiveness of tumors to conventional therapeutic agents might be due to inappropriate gene expression resulting from epigenetic modifications and leading to transcriptional silencing. The goal of this study was to evaluate the anticancer effect of a histone deacetylase inhibitor, valproate, on mesothelioma cells in combination with pemetrexed and cisplatin, the usual first-line regimen of chemotherapy for this tumor.

EXPERIMENTAL DESIGN AND RESULTS

We show that valproate augments apoptosis induced by pemetrexed and cisplatin in mesothelioma cell lines and in tumor cells from patient's biopsies. Onset of apoptosis involves both extrinsic and intrinsic pathways requiring enzymatic activities of caspases 8 and 9, respectively. Valproate but not suberoylanilide hydroxamic acid efficiently stimulates the production of reactive oxygen species. The free radical scavenger N-acetylcysteine inhibits apoptosis, indicating that reactive oxygen species are major mediators of valproate activity. As expected, valproate alone or combined with pemetrexed and cisplatin triggers hyperacetylation of histone H3. Bid protein processing in truncated t-Bid and cytochrome c release from mitochondria are significantly increased in the presence of valproate, providing a mechanistic rationale for improvement of the proapoptotic efficacy of cisplatin and pemetrexed. Finally, valproate when combined with pemetrexed and cisplatin prevents tumor growth in mouse models of epithelioid mesothelioma.

CONCLUSIONS

These observations support the potential additional efficacy of valproate in combination with pemetrexed and cisplatin for treatment of malignant mesothelioma.

Therapy for osteosarcoma: where do we go from here?

Osteosarcoma is the most common malignant primary bone tumor in children and adolescents. Current optimal treatment for osteosarcoma consists of multi-agent chemotherapy and aggressive surgical resection of all sites of disease involvement. The current national and international cooperative trial for patients with newly diagnosed osteosarcoma builds upon the backbone of cisplatin, doxorubicin, and methotrexate. This protocol is designed to clarify whether (i) the addition of ifosfamide and etoposide to postoperative chemotherapy with cisplatin, doxorubicin, and methotrexate improves the event-free survival and overall survival for patients with resectable osteosarcoma and a poor histologic response to 10 weeks of preoperative chemotherapy; and (ii) the addition of pegylated interferon-alpha-2b as maintenance therapy after postoperative chemotherapy with cisplatin, doxorubicin, and methotrexate improves the event-free survival and overall survival for patients with resectable osteosarcoma and a good histologic response to 10 weeks of preoperative chemotherapy. However, the optimal treatment strategy (or strategies) for patients with relapsed or metastatic disease has yet to be defined. This remains one of the persistent challenges in the treatment of osteosarcoma. Recent therapeutic advances have focused on circumventing chemotherapy resistance mechanisms, incorporation of non-classical agents into upfront therapy, targeting of the tumor micro-environment, and investigating the role of novel delivery mechanisms. In patients with localized disease the 5-year survival rate is at least 70%; patients with metastatic or recurrent disease have <20% chance of long-term survival despite aggressive therapies. These figures have changed little in the past 2 decades. This review focuses on the current therapy for osteosarcoma, and highlights emerging strategies that will hopefully change the outlook for patients with this disease.

Pemetrexed single agent chemotherapy in previously treated patients with locally advanced or metastatic non-small cell lung cancer

BACKGROUND

The main objective of this study was to evaluate the safety of second-line pemetrexed in Stage IIIB or IV NSCLC.

METHODS

Overall, 95 patients received pemetrexed 500 mg/m2 i.v. over Day 1 of a 21-day cycle. Patients also received oral dexamethasone, oral folic acid and i.m. vitamin B12 supplementation to reduce toxicity. NCI CTC 2.0 was used to rate toxicity. All the adverse events were graded in terms of severity and relation to study treatment. Dose was reduced in case of toxicity and treatment was delayed for up to 42 days from Day 1 of any cycle to allow recovering from study drug-related toxicities. Tumor response was measured using the RECIST criteria.

RESULTS

Patients received a median number of 4 cycles and 97.8% of the planned dose. Overall, 75 patients (78.9% of treated) reported at least one adverse event: 34 (35.8%) had grade 3 as worst grade and only 5 (5.2%) had grade 4. Drug-related events occurred in 57.9% of patients. Neutropenia (8.4%) and leukopenia (6.3 %) were the most common grade 3/4 hematological toxicities. Grade 3 anemia and thrombocytopenia were reported in 3.2% and 2.1% of patients, respectively. Diarrhea (6.3%), fatigue (3.2%) and dyspnea (3.2%) were the most common grade 3/4 non-hematological toxicities. The most common drug-related toxicities (any grade) were pyrexia (11.6%), vomiting, nausea, diarrhea and asthenia (9.5%) and fatigue (8.4%). Tumor Response Rate (CR/PR) in treated patients was 9.2%. The survival at 4.5 months (median follow-up) was 79% and the median PFS was 3.1 months. Twenty patients (21.1%) died mainly because of disease progression.

CONCLUSION

Patients with locally advanced or metastatic NSCLC could benefit from second-line pemetrexed, with a low incidence of hematological and non-hematological toxicities.

Pemetrexed combined with paclitaxel in patients with advanced or metastatic non-small-cell lung cancer: A phase I-II trial

Pemetrexed, a novel multi-targeted agent established for the treatment of mesothelioma, has been under investigation for other malignancies, and in recent years particularly for non-small-cell lung cancer (NSCLC). In the present trial we investigated pemetrexed in combination with paclitaxel as front-line treatment in advanced or metastatic NSCLC. Our objectives were to determine the response rate, median and overall survival and toxicity. From April 2005 until May 2006, 51 patients with advanced or metastatic NSCLC were enrolled and 48 were considered evaluable. There were 39 males and nine females, median age 62 years (range 37-81 years), one patient stage IIIA N(2), 23 patients, IIIB and 24, stage IV. All patients had a cytologically- or histologically-confirmed diagnosis. Pemetrexed was administered at a standard dose of 500mg/m(2) and paclitaxel at an escalating dose starting at 135mg/m(2), then 150mg/m(2) and ending at a dose of 175mg/m(2); the level was increased every three patients. Both agents were administered on day 1, repeated every 3 weeks for six courses. A 39.6% partial response rate was observed with a median survival of 14 months. Toxicity was mild with 8.3% grade 3 and 4 neutropenia and other very mild hematologic and non-hematologic adverse reactions. The combination of pemetrexed and paclitaxel at doses of 500mg/m(2) and 175mg/m(2), respectively, has been shown to be an effective combination with very limited toxicity.