Activity of pemetrexed (ALIMTA, multitargeted antifolate, LY231514) in metastatic breast cancer patients previously treated with an anthracycline and a taxane: an interim analysis

Comprehensive bioinformatics study reveals targets and molecular mechanism of hesperetin in overcoming breast cancer chemoresistance

The effectiveness of chemotherapy in breast cancer treatment can be increased using a combinatorial agent. Hesperetin has been reported to increase the sensitivity of doxorubicin in breast cancer cells; however, the underlying molecular mechanism remains unclear. This present study was conducted to identify the potential target and molecular mechanism of hesperetin in circumventing breast cancer chemoresistance using a bioinformatics approach. Microarray data obtained after hesperetin treatment in the NCI-60 cell line panel collection were retrieved from the COMPARE public library. These data were then compared with the list of the regulatory genes of breast cancer resistance obtained from PubMed and further analyzed for gene ontology and KEGG pathway enrichment, as well as protein-protein interaction network. A Venn diagram of COMPARE microarray data and the gene list from PubMed generated 56 genes (potential therapeutic target genes/PTTGs). These PTTGs participate in the biological process of the JAK-STAT cascade and are located in the nucleus, exert a molecular function in protein serine/threonine kinase activity, and regulate the erbB signaling pathway. Drug association analysis demonstrated that both hesperetin and the erbB receptor inhibitors, i.e., monoclonal antibody and tyrosine kinase inhibitor, target the same mRNA expression. Furthermore, results of the molecular docking study revealed that hesperetin is a promising inhibitor that targets ABL1, DNMT3B, and MLH1 due to the similarity of binding properties with its native ligand. In conclusion, the possible pathways and the regulatory genes identified in this study may offer new insights into the mechanism by which hesperetin overcomes breast cancer chemoresistance. A combinatorial therapy with hesperetin targeting ABL1, DNMT3B, and MLH1 may be effective in circumventing chemoresistance in breast cancer.

Pemetrexed-Induced Rash May Be Prevented by Supplementary Corticosteroids

Pemetrexed, a chemotherapeutic drug, is highly active in non-small cell lung cancer and malignant pleural mesothelioma. Unfortunately, rashes are more commonly associated with pemetrexed than other chemotherapies, and it is recommended that patients receive corticosteroids (8 mg/d of dexamethasone) for 3 d, including the day of pemetrexed administration (day 1). However, the efficacy of corticosteroids in this context has not been fully verified. In this retrospective study, we evaluated the medical records of 78 patients who received pemetrexed between April 2009 and March 2014, to confirm whether supplementary corticosteroids prevented rash development. The incidence of rash was lower in the 47 patients who received supplementary corticosteroids (after day 1) compared with the incidence among the 31 patients who did not receive supplementary corticosteroids (19.1% vs. 38.7%). The average cutoff dosage of supplementary corticosteroids on day 2 and day 3 was 1.5 mg/d of dexamethasone, as calculated using the receiver operating characteristic curve, and the odds ratio was 0.33 (95% confidence interval: 0.12-0.94). Administration of ≥1.5 mg of corticosteroids on day 2 and day 3 significantly reduced the severity of the rash compared to no supplementary treatment (grades 2/3, 13.3% vs. 33.3%, p<0.05). However, increasing the dose of corticosteroids had no additional effect on rash development. These results suggest that ≥1.5 mg of supplementary dexamethasone on day 2 and day 3 (in addition to day 1) may be necessary for preventing pemetrexed-induced rash, but high doses of dexamethasone (e.g., 8 mg/d) are unnecessary.

Potential role of pemetrexed in metastatic breast cancer patients pre-treated with anthracycline or taxane

Objectives

This article reviews pharmacology, pharmacokinetic properties, clinical efficacy, and safety in metastatic breast cancer patients, as well as the predictive biomarkers for outcome of treatment with pemetrexed-based regimens.

Methods

PubMed, Embase, OVID, and the Cochrane Library databases were searched from the beginning of each database without any limitations to the date of publication. Search terms were ‘‘pemetrexed’’ or ‘‘LY231514’’ or “Alimta”, “metastatic breast cancer”, and “advanced breast cancer”.

Results

There were 15 studies (n = 1002) meeting our criteria for evaluation. Eight single-agent trials (n = 551) and seven using combinations with other agents (n = 451) were identified that evaluated pemetrexed for use in patients with metastatic breast cancer. Response rates to pemetrexed as a single agent varied from 8% to 31%, and with combination therapy have been reported to be between 15.8% and 55.7%. With routine supplementation of patients with folic acid, dexamethasone, and vitamin B₁₂, the toxicity profile of these patients was mild, including dose-limiting neutropenia and thrombocytopenia, as well as lower grades of reversible hepatotoxicity and gastrointestinal toxicity. Expression of thymidylate synthase (TS) and other biomarkers are associated with the prognosis and sensitivity for pemetrexed in breast cancer.

Conclusion

Pemetrexed has shown remarkable activity with acceptable toxicities for treatment of metastatic breast cancer patients. Translational research on pemetrexed in breast cancer identified biomarkers as well as additional genes important to its clinical activity and toxicity. Further research is needed to clarify the role of pemetrexed in breast cancer treatment in order to guide oncologists.

[Pemetrexed nephrotoxicity]

Pemetrexed belongs to a new generation of multitargeted antifolate cytotoxic agents. It is increasingly used as first-line treatment in combination with cisplatin, and as second-line treatment or maintenance monotherapy mainly in metastatic non-small cell lung cancer and in malignant mesothelioma. It is increasingly used as first-line treatment in combination with cisplatin in lung adenocarcinoma, and as second-line treatment or maintenance monotherapy in patients mainly controlled by the first-line to progression or poor tolerance. In mesothelioma, pemetrexed is indicated only in first-line with a platinum salt. The main side effect of pemetrexed is myelosuppression, which may be prevented by folinic acid supplementation. This review focuses on the progressive and cumulative emerging renal toxicity of pemetrexed, affecting five to ten percent of "long-term" pemetrexed-treated patients.

A phase II multicenter study of two different dosages of pemetrexed given in combination with cyclophosphamide as first-line treatment in patients with locally advanced or metastatic breast cancer

Pemetrexed/cyclophosphamide was evaluated as first-line treatment for patients with locally advanced/metastatic breast cancer. In this randomized phase II study (NCT00190671), therapy consisted of either 600 mg/m(2) (P600) or 1,800 mg/m(2) (P1800) pemetrexed, followed by 600 mg/m(2) cyclophosphamide, every 21 days; 103 females (42 P600; 61 P1800) were enrolled. P600 was discontinued, as response rate (19.1%) was lower than targeted. In the P1800 arm, 20 patients had partial response (32.8%; 95% CI: 21.0-44.6) and 26 (42.6%) had stable disease. Median progression-free survival was 6.3 months (range: 0.3-31.1). P1800 plus cyclophosphamide 600 represents a regimen of reasonable efficacy and acceptable tolerability.

Safety and pharmacokinetics of intrathecal administration of pemetrexed in rats

PURPOSE

Leptomeningeal carcinomatosis is a devastating complication of malignant disease. In this study, we evaluated the safety and pharmacokinetics of intrathecally administered pemetrexed in rats.

METHODS

Three levels of pemetrexed (0.3, 1, and 3 mg/kg) were administered to 15 rats per level (45 rats in total) twice a week for 2 weeks through specifically designed indwelling subarachnoid catheters. Presence of clinical and pathological neurotoxicity was evaluated. To evaluate the pharmacokinetics of pemetrexed, independent cohorts of 30 rats were treated with 1 mg/kg of pemetrexed and its concentration in cerebrospinal fluid (CSF) and blood was measured using UPLC/MS/MS.

RESULTS

There were no cases of clinical or pathologic neurotoxicity after intrathecal administrations of pemetrexed at levels of 0.3 and 1 mg/kg; however, 5 of 15 (33%) rats died after administration of 3 mg/kg pemetrexed. The distribution/elimination of pemetrexed in CSF was best described by a two-compartment model, with initial and terminal half-lives of 0.43 and 1.43 h, respectively. The predicted maximal concentration in CSF was 588 μM, and high levels of pemetrexed appeared to be maintained for a long time. Area under the curve and volume of distribution at steady state were 560 μM h and 1.14 ml, respectively.

CONCLUSIONS

The no observed adverse effect level of intrathecal administration of pemetrexed was 1 mg/kg in rats. At this level, therapeutically high and durable pemetrexed concentrations could be achieved. Based on these results, further research on intrathecal pemetrexed in humans or non-human primates should be considered.

Comparison of patient outcomes according to histology among pemetrexed-treated patients with stage IIIB/IV non-small-cell lung cancer in two phase II trials

INTRODUCTION

Recent phase III studies in advanced non-small-cell lung cancer (NSCLC) have demonstrated differential efficacy for pemetrexed according to NSCLC histology. The results of 2 phase II studies of pemetrexed and a platinum agent (carboplatin or oxaliplatin) were pooled to determine whether outcomes in the studies differed by tumor histology.

PATIENTS AND METHODS

Chemotherapy-naive patients with stage IIIB/IV NSCLC received pemetrexed 500 mg/m2 plus carboplatin area under the curve of 6 (n = 89) or pemetrexed 500 mg/m2 plus oxaliplatin 120 mg/m2 (n = 41); both regimens were administered every 21 days. The primary endpoint of both trials was response rate. Treatment arms were pooled, and Cox models with main effects for squamous histology were used to assess overall survival and progression-free survival. Cofactor adjustments incorporated terms for performance status, disease stage, and sex.

RESULTS

More than three quarters of enrolled patients had a nonsquamous histology. Mean age was 59.9 years for patients with nonsquamous histology and 63.7 years for patients with squamous histology. Response rates were 30% for patients with nonsquamous histology and 17.2% for patients with squamous histology. Overall survival was 10.5 months for patients with nonsquamous histology and 9.8 months for patients with squamous histology (hazard ratio [HR], 0.95; 95% CI, 0.52-1.74). Progression-free survival was 5.6 months for patients with nonsquamous histology and 4.7 months for patients with squamous histology (HR, 0.72; 95% CI, 0.43-1.19).

CONCLUSION

In patients treated with pemetrexed/ platinum doublets, nonsquamous histology was associated with better outcomes. The benefit of pemetrexed treatment among patients with nonsquamous histology is consistent with the results reported from previous studies.

Feasibility study of dose-dense biweekly administered pemetrexed in patients with non-small cell lung cancer

BACKGROUND AND OBJECTIVES

Pemetrexed is a multitargeted folate pathway inhibitor with documented activity in non-small cell lung cancer (NSCLC). The presumed maximum tolerated dose is 500 mg/m2 every 3 weeks, but pemetrexed-related toxicity is ameliorated when folate and B12 supplementation is provided and therefore a higher dose intensity may be tolerated. The current exploratory study assessed the feasibility of administration of pemetrexed at a fixed dose of 1000 mg every 2 weeks in patients with relapsed or refractory NSCLC.

PATIENTS AND METHODS

The first cohort of 12 patients received pemetrexed monotherapy. No dose-limiting grade 4 toxicity was noted after 4 cycles, so the subsequent cohort of 14 patients received additional anticancer agents (bevacizumab, erlotinib, carboplatin, docetaxel, vinorelbine) given along with dose-dense pemetrexed.

RESULTS

Toxicity overall was reversible and manageable. Among 19 patients who received pemetrexed either alone or with non-myelosuppressive targeted agents, there were only 2 instances of grade 4 neutropenia after prolonged treatment. Grade 3-4 hematologic toxicity was eventually noted in 11 of the 26 patients (42%; 95% confidence interval, 23% to 61%) after a median of 4 cycles (range, 2-14 cycles). There was no significant additional toxicity nor any treatment-related deaths.

CONCLUSION

Our preliminary observations indicate that dose-dense pemetrexed every 2 weeks is feasible and this regimen can be used as monotherapy. These data may serve as a scaffold for combination studies.

Phase I trial and pharmacokinetic study of pemetrexed in children with refractory solid tumors: the Children's Oncology Group

PURPOSE

We report results of a phase I trial and pharmacokinetic study of pemetrexed (LY231514) in children and adolescents with refractory solid tumors. Pemetrexed is a novel antifolate that inhibits multiple enzymes necessary for the biosynthesis of thymidine and purine nucleotides. The purpose of this study was to determine the maximum-tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetic properties of pemetrexed in children.

PATIENTS AND METHODS

Pemetrexed was administered as a 10-minute intravenous infusion every 21 days. Patients received vitamin B12 and folic acid supplementation as well as dexamethasone prophylaxis. Cohorts of three to six children were enrolled at dose levels of 400, 520, 670, 870, 1,130, 1,470, 1,910, and 2,480 mg/m2. Pharmacokinetic studies were performed during the first course of treatment.

RESULTS

Thirty-three patients (31 assessable) with a median age of 12 years were enrolled. DLT occurred in one of six patients at 1,470 mg/m2 and two of four patients at 2,480 mg/m2. The MTD was 1,910 mg/m2. The primary DLTs were neutropenia and rash. No objective antitumor responses were seen. Mean plasma clearance, half-life, and steady-state volume of distribution values were 2.3 L/h/m2, 2.5 hours, and 5.4 L/m2, respectively.

CONCLUSION

Pemetrexed is well-tolerated in children with refractory solid tumors at doses similar to the MTD in adults. The recommended dose for phase II studies is 1,910 mg/m2 administered every 21 days with dexamethasone, folic acid, and vitamin B12 supplementation.

Pemetrexed (Alimta, LY231514) demonstrates clinical activity in chemonaive patients with cervical cancer in a phase II single-agent trial

The objective of this study was to determine the response rate in chemonaive patients with inoperable, locally advanced, recurrent, or metastatic cervical cancer treated with pemetrexed (Alimta, LY231514), a multitargeted antifolate. The patients were treated with either 500 mg/m(2) (11 patients) or 600 mg/m(2) (24 patients) of pemetrexed, administered as a 10-min infusion on day 1 of a 21-day cycle. Patients receiving 500 mg/m(2) dose also received 5 mg/day oral folic acid supplementation beginning 2 days prior and ending on day 3 of each cycle. Of the 34 patients evaluable for efficacy, six patients (18%) had partial response, with median response duration of 3.8 months (range, 3.3-6.6 months). Twenty-four patients (71%) had stable disease, one patient (3%) had progressive disease, and three patients could not be assessed. Median overall survival was 15.2 months (range, 2.9-35.3+ months). Grade 4 hematologic toxicities consisted of neutropenia (37%), leukopenia (9%), anemia (6%), and thrombocytopenia (3%). One patient died of hypotensive shock associated with frank rectal hemorrhage that was considered to be related to the study drug. We conclude that pemetrexed therapy showed moderate activity, similar to other active agents, in the treatment of locally advanced or metastatic cervical cancer.

Single-arm, open label study of pemetrexed plus cisplatin in chemotherapy naïve patients with malignant pleural mesothelioma: Outcomes of an expanded access program

BACKGROUND

An expanded access program (EAP) provided patient access to pemetrexed prior to its commercial availability. The current report consists of US patients in the EAP who had chemotherapy naïve pleural mesothelioma.

METHODS

Eligible patients had a histologic or cytologic diagnosis of malignant mesothelioma that was not amenable to curative treatment with surgery. Study treatment consisted of pemetrexed 500mg/m(2) in combination with cisplatin 75mg/m(2) once every 21 days. Vitamin B12, folic acid, and dexamethasone were administered as prophylaxis. Serious adverse events (SAEs) were reported by investigators and compiled in a pharmacovigilance database for all patients enrolled in the EAP.

RESULTS

Of 1056 patients receiving at least one dose of pemetrexed in the EAP, 728 had chemotherapy naïve pleural mesothelioma. Median age of this group was 70 years (range 23-89 years) and 84% were male. Among 615 patients, overall response rate was 20.5%, including 12 complete responses (2.0%) and 114 partial responses (18.5%). An additional 290 patients (47.2%) had stable disease. Median survival for all 728 patients was 10.8 months (95% CI=9.8, 12.3; 60.3% censorship) and 1 year survival was 45.4%. The most commonly reported SAEs in the overall EAP irrespective of causality were dehydration (7.2%), nausea (5.2%), vomiting (4.9%), dyspnea (3.8%), and pulmonary embolism (2.4%).

CONCLUSIONS

In this large cohort, 67.7% of patients treated with first-line chemotherapy experienced a response or stable disease. Survival time and toxicity from this EAP were promising for this difficult-to-treat disease.

A Phase I Study of Pemetrexed (ALIMTA) and Cyclophosphamide in Patients with Locally Advanced or Metastatic Breast Cancer

PURPOSE

Determine the maximum tolerated dose (MTD) of pemetrexed and cyclophosphamide combination therapy for patients with locally advanced or metastatic breast cancer.

EXPERIMENTAL DESIGN

Patients with locally advanced or metastatic breast cancer and WHO performance status 0 to 2 were eligible. Pemetrexed (range, 400-2,400 mg/m(2)) was administered on day 1 of a 21-day schedule followed by cyclophosphamide (range, 400-800 mg/m(2)). Folic acid and vitamin B(12) supplementation began 1 to 2 weeks before the first pemetrexed dose.

RESULTS

Fifty-seven pretreated patients were enrolled and received 342 cycles (median, 4 cycles; range, 1-26) through 14 dose levels. The MTD of pemetrexed was 2,400 mg/m(2) (combined with cyclophosphamide, 600 mg/m(2)) with dose-limiting toxicities of grade 4 neutropenia with grade 4 infection and grade 3 diarrhea. Other grade 3 or 4 toxicities included (febrile) neutropenia, thrombocytopenia, anemia, elevated alanine aminotransferase/aspartate aminotransferase, and diarrhea. Pharmacokinetic analysis indicated that pemetrexed clearance and central volume of distribution were 40% lower than single-agent reference data, yielding a 68% increase in total systemic exposure and a 56% increase in maximal plasma concentration. Among the 50 patients evaluable for efficacy, 13 (26%) patients had a partial response and 17 (34%) patients had stable disease.

CONCLUSIONS

Pemetrexed was generally well tolerated. The observed toxicities were consistent with the known toxicity profiles of pemetrexed and cyclophosphamide. Considering the MTD and the toxicity and efficacy results in this and prior studies, a low (600 mg/m(2)) and a high (1,800 mg/m(2)) dose of pemetrexed with cyclophosphamide (600 mg/m(2)) will be evaluated in the consecutive prospective randomized phase II study.

Randomized Phase II Trial of Pemetrexed Combined With Either Cisplatin or Carboplatin in Untreated Extensive-Stage Small-Cell Lung Cancer

Purpose

Given the activity and tolerability of pemetrexed/platinum combinations in non–small-cell lung cancer, and the success of novel therapeutic strategies employed in recent extensive-stage small-cell lung cancer (ES-SCLC) trials, a randomized phase II trial was initiated to evaluate the use of cisplatin or carboplatin plus pemetrexed in previously untreated ES-SCLC.

Patients and Methods

Patients were randomly assigned to receive pemetrexed 500 mg/m2 plus cisplatin 75 mg/m2 or pemetrexed plus carboplatin area under the concentration curve 5. Treatment was administered once every 21 days for a maximum of six cycles. All patients received folic acid, vitamin B12, and steroid prophylaxis.

Results

Between December 19, 2002, and May 17, 2004, 78 patients were enrolled onto this multicenter trial. Median age was 63 years (range, 46 to 82 years) for cisplatin/pemetrexed and 66 years (range, 47 to 75 years) for carboplatin/pemetrexed. Median survival time (MST) for cisplatin/pemetrexed was 7.6 months, with a 1-year survivorship of 33.4% and a response rate of 35% (95% CI, 20.6% to 51.7%). The MST for carboplatin/pemetrexed was 10.4 months, with a 1-year survivorship of 39.0% and a response rate of 39.5% (95% CI, 24.0 to 56.6). Median time to progression for cisplatin/pemetrexed was 4.9 months and for carboplatin/pemetrexed was 4.5 months. Median dose-intensity (actual/planned dose) was 98.94% for cisplatin and 99.95% for pemetrexed in the cisplatin/pemetrexed group and 93.21% for carboplatin and 98.50% for pemetrexed in the carboplatin/pemetrexed group. Grade 3/4 hematologic toxicities included neutropenia (15.8% v 20.0%) and thrombocytopenia (13.2% v 22.9%) in the cisplatin/pemetrexed and carboplatin/pemetrexed treatment groups, respectively.

Conclusion

Pemetrexed/platinum doublets had activity and appeared to be well-tolerated in first-line ES-SCLC.

A phase II study of an oxaliplatin/vinorelbine/5-fluorouracil combination in patients with anthracycline-pretreated and taxane-pretreated metastatic breast cancer

The aim of this phase II study was to evaluate safety and efficacy of an oxaliplatin/vinorelbine/5-fluorouracil (FON) combination in anthracycline and taxane-pretreated metastatic breast cancer patients. The following treatment was given: on day 1 of a 21-day cycle, oxaliplatin 130 mg/m (2-h intravenous infusion); on days 1 and 5, vinorelbine [dose level (DL) 1: 17.5 mg/m; DL2: 22 mg/m]; on days 1-5, continuous infusion 5-fluorouracil (DL1: 600 mg/m/day; DL2: 750 mg/m/day). Forty-seven patients were treated (DL1: 43; DL2: 4). Median age was 54 years; 68% had liver metastases, 53% were taxane refractory/resistant and 38% were anthracycline refractory/resistant. Patients received a median of six treatment cycles. Of 46 eligible patients, 16 had partial response; the overall response rate was 34.8% (95% confidence interval 21.3-50.3%), 11 had stable disease lasting more than 4 months. Median follow-up was 13.0 months, median time to progression 5.7 months and estimated overall survival 18.8 months. DL2 was too toxic with three patients having grade 3-4 toxicity, including one death. At DL1, 26 patients (60%) experienced grade 3-4 neutropenia (six febrile neutropenia) and eight had grade 3 oxaliplatin-specific peripheral neuropathy after a median of 646.4 mg/m oxaliplatin (range 124-1619 mg/m). Oxaliplatin (130 mg/m, day 1)/vinorelbine (17.5 mg/m, days 1,5)/5-fluorouracil (600 mg/m/day, days 1-5) demonstrate encouraging activity and a manageable safety profile in anthracycline- and taxane-pretreated metastatic breast cancer patients.

Administration of pemetrexed immediately following gemcitabine as front-line therapy in advanced non-small cell lung cancer: A phase II trial

BACKGROUND

Pemetrexed and gemcitabine have demonstrated independent anti-tumor activity in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC). The combination of these two therapies may produce synergistic anti-tumor effects. Previous studies of this combination have included a 90-min separation between the two drugs. More recent preclinical studies have suggested that this delay in administration might be unnecessary. This phase II study was designed to determine the objective tumor response rate and toxicity when pemetrexed was administered immediately after gemcitabine on day 1.

METHODS

Chemonaïve patients stage IIIB with pleural effusion or stage IV NSCLC were enrolled. Treatment consisted of gemcitabine 1250 mg/m2 (30-min intravenous infusion on days 1 and 8) and pemetrexed 500 mg/m2 (10-min i.v. infusion, immediately following gemcitabine, on day 1) every 21 days. All patients received folic acid, vitamin B12, and steroid prophylaxis.

RESULTS

The 53 enrolled patients completed a total of 199 cycles (median=4.0, mean=3.8). Best tumor response consisted of 1 complete response (2.0%), 15 partial responses (30.6%), 17 with stable disease (34.7%), and 16 with progressive disease (32.7%). Median time to disease progression was 3.3 months and median survival was 10.3 months. Grades 3/4 hematologic toxicities (% patients) consisted of: neutropenia (43.4), anemia (9.4), febrile neutropenia (7.5%) and thrombocytopenia (1.9). The most common grades 3 or 4 non-hematologic events were: dyspnea (15.1), fatigue (11.3), and pyrexia (9.4). One patient (1.9%) experienced grade 2 alopecia.

CONCLUSION

This schedule of pemetrexed plus gemcitabine is tolerable and offered the advantage of not requiring a 90-min delay between the two drugs. Response rate, survival, time to disease progression, and toxicity were acceptable and similar to other NSCLC regimens.

Phase II study of an oxaliplatin/vinorelbine combination in patients with anthracycline- and taxane-pre-treated metastatic breast cancer

A phase II study was conducted to evaluate the safety and efficacy of an oxaliplatin (OXA)/vinorelbine (VNB) combination in metastatic breast cancer (MBC) patients pre-treated with anthracyclines and taxanes. Patients received OXA at 130 mg/m (2-h i.v.), day 1, and VNB days 1 and 8 at 24-26 mg/m repeated every 3 weeks. Forty-two patients (median age 54; 64% with liver metastasis, 67% taxane resistant/refractory and 38% anthracycline resistant/refractory) were treated. A median of 4 cycles of treatment was given per patient, with 31% receiving 6 or more. Eleven partial responses and 16 patients with stable disease (five lasting more than 4 months) in 41 eligible patients were seen, for an overall response rate of 26.8% (95% confidence interval 14.2-42.9). Median follow-up was 15.9 months (7.2-30.6), median time to progression was 3.4 months and estimated overall survival was 12.7 months (20 events). Thirty-three patients experienced (National Cancer Institute Common Toxicity Criteria version 2) grade 3-4 neutropenia (one case of febrile neutropenia) and three patients had severe constipation requiring hospitalization. Nine patients developed grade 3 OXA-specific neurotoxicity. There were no treatment-related deaths. We conclude that OXA 130 mg/m (day 1) and VNB 24 mg/m (day 1 and 8) combination given every 3 weeks is effective with a good safety profile in MBC patients previously treated with anthracyclines and taxanes.

A phase II trial of a combination of pemetrexed and gemcitabine in patients with metastatic breast cancer: an NCCTG study

PURPOSE

This phase II study was undertaken to define the efficacy and toxicity of pemetrexed in combination with gemcitabine in patients with metastatic breast cancer.

PATIENTS AND METHODS

Patients with measurable metastatic breast cancer who had previously received an anthracycline and a taxane in either the adjuvant or metastatic setting were treated with gemcitabine 1250 mg/m2 (intravenous; days 1 and 8) and pemetrexed 500 mg/m2 (intravenous; day 8) every 21 days.

RESULTS

Fifty-nine patients received a median of five cycles (range one to 22) of treatment and were followed until death or for a median of 28 months (range 19.4-36.6) among living patients. Fourteen partial responses for an overall response rate of 24% [95% confidence interval (CI) 16% to 39%] were documented. Nine (15%; CI 5% to 32%) patients had stable disease for >6 months. The median survival time was 10.3 months (95% CI 8.3-18.9) and the 1 year survival rate was 49% (95% CI 38% to 64%). The median time to progression was estimated to be 3.7 months (95% CI 2.3-5.3). The most common grade 3 or 4 toxicities were neutropenia and thrombocytopenia in 83% and 27% of patients, respectively. Fourteen percent of patients experienced febrile neutropenia. Other common grade 3 or 4 non-hematological toxicities included fatigue (17%), dyspnea (15%), rash (7%) and anorexia (5%).

CONCLUSIONS

The combination of pemetrexed and gemcitabine is clinically active, with an overall response rate of 24% in patients with metastatic breast cancer who have previously been treated with an anthracycline and a taxane. Myelosuppression (66% grade 4 neutropenia and 14% febrile neutropenia) was the major treatment-related toxicity observed for this combination.

Phase I and Pharmacokinetic Study of Pemetrexed Administered Every 3 Weeks to Advanced Cancer Patients With Normal and Impaired Renal Function

Purpose

This phase I study was conducted to determine the toxicities, pharmacokinetics, and recommended doses of pemetrexed in cancer patients with normal and impaired renal function.

Patients and Methods

Patients received a 10-minute infusion of 150 to 600 mg/m2 of pemetrexed every 3 weeks. Patients were stratified for independent dose escalation by measured glomerular filtration rate (GFR) into four cohorts ranging from ≥ 80 to less than 20 mL/min. Pemetrexed plasma and urine pharmacokinetics were evaluated for the first cycle. Patients enrolled after December 1999 were supplemented with oral folic acid and intramuscular vitamin B12.

Results

Forty-seven patients were treated with 167 cycles of pemetrexed. Hematologic dose-limiting toxicities occurred in vitamin-supplemented patients (two; 15%) and nonsupplemented patients (six; 18%), and included febrile neutropenia (four patients) and grade 4 thrombocytopenia (two patients). Nonhematologic toxicities included fatigue, diarrhea, and nausea, and did not correlate with renal function. Accrual was discontinued in patients with GFR less than 30 mL/min after one patient with a GFR of 19 mL/min died as a result of treatment-related toxicities. Pemetrexed plasma clearance positively correlated with GFR (r2 = 0.736), resulting in increased drug exposures in patients with impaired renal function. With vitamin supplementation, pemetrexed 600 mg/m2 was tolerated by patients with a GFR ≥ 80 mL/min, whereas patients with a GFR of 40 to 79 mL/min tolerated a dose of 500 mg/m2.

Conclusion

Pemetrexed was well tolerated at doses of 500 mg/m2 with vitamin supplementation in patients with GFR ≥ 40 mL/min. Additional studies are needed to define appropriate dosing for renally impaired patients receiving higher dose pemetrexed with vitamin supplementation.

Clinical Experience With Pemetrexed in Breast Cancer

Alimta (pemetrexed) is a novel multitargeted antifolate that inhibits several enzymes in the de novo pathways of pyrimidine and purine biosynthesis, including thymidylate synthase, dihydrofolate reductase, and glycinamide ribonucleotide formyltransferase. Pemetrexed possesses antitumor activity in several solid tumors, including non-small cell lung cancer, malignant pleural mesothelioma, pancreas, colorectal, gastric, bladder, breast, and head and neck cancers. The main toxicities of the drug are myelosuppression, skin rash, and mucositis. Both myelosuppression and mucositis are more frequent in patients with high homocysteine plasma levels (an indicator of deficient vitamin B₁₂ and folate pools). Supplementation with vitamin B₁₂ and folic acid greatly reduces most severe toxicities and has been implemented in pemetrexed trials since December 1999. Pemetrexed has been tested in five phase II trials in locally advanced or metastatic breast cancer. The drug has shown an activity of around 30% in advanced breast cancer patients with minimal or no prior chemotherapy. In patients who received prior anthracyclines, response rates of 21% were reported. Responses have also been observed in a moderate proportion of patients who had been pretreated with anthracyclines, taxanes, and capecitabine. Some studies have suggested that a correlation exists between thymidylate synthase tumor expression with pemetrexed antitumor activity; this attractive hypothesis should be confirmed in further studies. The optimal dose when combined with vitamin supplementation is under current investigation in patients with breast cancer. A randomized phase II study comparing pemetrexed 600 and 900 mg/m² with vitamin supplementation as first-line treatment for metastatic breast cancer is ongoing.

A semimechanistic-physiologic population pharmacokinetic/pharmacodynamic model for neutropenia following pemetrexed therapy

PURPOSE

The objectives of these analyses were to (1) develop a semimechanistic-physiologic population pharmacokinetic/pharmacodynamic (PK/PD) model to describe neutropenic response to pemetrexed and to (2) identify influential covariates with respect to pharmacodynamic response.

PATIENTS AND METHODS

Data from 279 patients who received 1,136 treatment cycles without folic acid or vitamin B12 supplementation during participation in one of eight phase II cancer trials were available for analysis. Starting doses were 500 or 600 mg pemetrexed per m2 body surface area (BSA), administered as 10-min intravenous infusions every 21 days (1 cycle). The primary analyses included 105 patients (279 cycles) for which selected covariates-including vitamin deficiency marker data (i.e., homocysteine, cystathionine, methylmalonic acid, and methylcitrate [I, II, and total] plasma concentrations)-were available. Classical statistical multivariate regression analyses and a semimechanistic-physiologic population PK/PD model were used to evaluate neutropenic response to single-agent pemetrexed administration.

RESULTS

The timecourse of neutropenia following single-agent pemetrexed administration was adequately described by a semimechanistic-physiologic model. Population estimates for system-based model parameters (i.e., baseline neutrophil count, mean transit time, and the feedback parameter), which mathematically represent current understanding of the process and physiology of hematopoiesis, were consistent with previously reported values. The population PK/PD model included homocysteine, cystathionine, albumin, total protein, and BSA as covariates relative to neutropenic response.

CONCLUSION

These results support the programmatic decision to introduce folic acid and vitamin B12 supplementation during pemetrexed clinical development as a means of normalizing patient homocysteine levels, thereby managing the risk of severe neutropenia secondary to pemetrexed administration. The current results also suggest that the addition of vitamin B6 supplementation to normalize patient cystathionine levels may further decrease the incidence of grade 4 neutropenia following pemetrexed administration. The results also suggest the use of folic acid as a means of lessening hematologic toxicity following administration of cytotoxic agents other than antifolates.

Population pharmacokinetic analysis of ten phase II clinical trials of pemetrexed in cancer patients

PURPOSE

The objectives of these population pharmacokinetic analyses were to (1) assess the overall disposition of pemetrexed, (2) characterize between-patient and within-patient variability and identify influential covariates with respect to pemetrexed pharmacokinetics; and, (3) provide individual empirical Bayesian estimates of pharmacokinetic parameters for use in a subsequent pharmacokinetic/pharmacodynamic evaluation of neutropenia following pemetrexed administration.

PATIENTS AND METHODS

Data from 287 patients who received 441 cycles without folic acid or vitamin B12 supplementation during participation in one of ten phase II cancer trials were evaluated by population pharmacokinetic analysis using NONMEM. Starting doses were 500 or 600 mg pemetrexed per m2 body surface area, administered as 10-min intravenous infusions every 21 days (1 cycle). The model was developed using data from eight of the ten studies. Predictive performance was evaluated using data from the other two studies.

RESULTS

The population pharmacokinetics of pemetrexed administered as a 10-min intravenous infusion are well characterized by a two-compartment model. Typical values of total systemic clearance, central volume of distribution, distributional clearance, and peripheral volume of distribution were 91.6 ml/min, 12.9 l, 14.4 ml/min, and 3.38 l, respectively. Based on these parameter estimates, the terminal elimination half-life of pemetrexed was approximately 3.5 h. Renal function was identified as a covariate with respect to total systemic clearance, and body surface area as a covariate with respect to the central volume of distribution.

CONCLUSION

Total systemic exposure (AUC) for a given dose of pemetrexed increases as renal function decreases. Since pharmacodynamic analyses have shown that AUC and not C (max) is the primary determinant of neutropenic response to pemetrexed, this suggests that dose adjustments based on renal function, rather than body surface area, might be considered for pemetrexed.

An evaluation of pemetrexed in second-line treatment of non-small cell lung cancer

Pemetrexed is a novel antifolate antimetabolite that targets multiple folate-dependent enzymatic pathways and inhibits multiple enzymes involved in purine and pyrimidine synthesis. Its targets include pathways that, when amplified, are associated with reduced efficacy in conventional cytotoxic agents. As second-line treatment for advanced non-small cell lung cancer, (NSCLC) pemetrexed, when administered with folic acid and vitamin B12, has demonstrated comparable efficacy and a superior toxicity profile relative to docetaxel. A retrospective analysis of the Phase III trial of pemetrexed versus docetaxel shows a statistically significant longer toxicity-free survival time for pemetrexed compared with docetaxel. Newer targeted therapies, especially the epidermal growth factor receptor inhibitors gefitinib and erlotinib, have produced conflicting results and have only been compared with best supportive care and placebo. They should be compared directly to pemetrexed as second-line therapy in large, randomised studies of patients with advanced NSCLC. For patients with advanced recurrent NSCLC and good performance status who progress after first-line chemotherapy, pemetrexed should be considered as a new standard of care.

Randomized phase II trial of three schedules of pemetrexed and gemcitabine as front-line therapy for advanced non-small-cell lung cancer

PURPOSE

A randomized three-arm phase II study was undertaken to evaluate the optimum administration schedule of pemetrexed and gemcitabine in chemotherapy-naïve patients with non-small-cell lung cancer.

PATIENTS AND METHODS

Patients were randomly assigned to three schedules of pemetrexed 500 mg/m2 plus gemcitabine 1,250 mg/m2, separated by a 90-minute interval, on a 21-day cycle as follows: schedule A, pemetrexed followed by gemcitabine on day 1 and gemcitabine on day 8; schedule B, gemcitabine followed by pemetrexed on day 1 and gemcitabine on day 8; and schedule C, gemcitabine on day 1 and pemetrexed followed by gemcitabine on day 8.

RESULTS

One hundred fifty-two eligible patients (schedule A, n = 59; schedule B, n = 31, and schedule C, n = 62) received a median of five (schedule A), two (schedule B), and four (schedule C) treatment cycles. Overall, 66% of patients experienced grade 3 or 4 neutropenia. Common grade 3 and 4 nonhematologic toxicities were dyspnea (11%), fatigue (16%), and transaminase elevation (9%). Schedule A seemed less toxic compared with schedule C (grade 3 or 4 events: 86% v 94%, respectively; P = .19; grade 4 events: 39% v 48%, respectively; P = .30). Schedule B was closed at interim analysis for inferior efficacy. Schedule A, with a confirmed response rate of 31% (95% CI, 20% to 45%), met the protocol-defined efficacy criteria, whereas schedule C, with a confirmed response rate of 16.1% (95% CI, 11% to 34%), did not. Median survival time and time to progression were 11.4 and 4.4 months, respectively, with no observable difference between the arms.

CONCLUSION

Pemetrexed and gemcitabine administered as outlined for schedule A met the protocol-defined efficacy criteria, was less toxic compared with the other treatment schedules, and should be further evaluated.

Malignant Pleural Mesothelioma

The diagnosis and management of malignant pleural mesothelioma are major challenges that often frustrate both patient and clinician alike. Occupational asbestos exposure to crocidolite or amosite forms of the fiber is the most important known risk factor in North America and Western Europe. Other mineral fibers such as erionite, a naturally occurring fibrous zeolite crystal, are associated with mesothelioma in volcanic tuffs of the Cappadocia region of central Anatolia in Turkey. In addition, other possible factors such as the presence of simian virus 40 and genetic susceptibility have been associated recently with the development of mesothelioma in animal models. These latter findings are increasing our understanding of this disease. In addition, the discovery of elevated levels of various markers such as folic acid receptor alpha, cyclooxygenase 2, and multidrug resistance proteins 1 and 2 in mesothelioma tissue have opened up new areas of potential diagnostic and therapeutic importance. However, traditional treatment modalities--surgery, radiotherapy, and chemotherapy--have evolved slowly, and few gains in therapeutic efficacy have occurred. Recently, however, continuing research efforts have led to novel treatment strategies that are changing the way clinicians view a disease that has traditionally been managed with almost universal therapeutic nihilism. This review explores our current knowledge of this disease and presents current and novel therapeutic strategies.

Phase II study of pemetrexed in breast cancer patients pretreated with anthracyclines

BACKGROUND

To assess antitumor activity and toxicity of pemetrexed in metastatic breast cancer (MBC) patients previously treated with anthracyclines.

PATIENTS AND METHODS

Seventy-seven MBC patients from 12 European institutions were entered into the study. Seventy-two patients were considered evaluable for response and toxicity. Forty-two patients were classified as anthracycline-failure (relapse >30 days after completion of a prior anthracycline regimen) and 30 as anthracycline-refractory (progression within 30 days after anthracycline therapy). Pemetrexed 600 mg/m(2) was administered intravenously every 3 weeks until progressive disease or unacceptable toxicity.

RESULTS

There were three complete and 12 partial responders [response rate 21% (95% confidence interval 12%)]. Response rates in the anthracycline-failure and anthracycline-refractory groups were 24% and 17%, respectively. A subset of 31 patients pretreated with anthracyclines and taxanes had a response rate of 26%. Median duration of response and median survival were 5.5 and 10.7 months, respectively (13 months in the failure group and 5.7 months for refractory). Grade 3/4 toxicities included neutropenia and thrombocytopenia in 56% and 19% of patients, respectively. Nine patients (12%) experienced neutropenic fever. Grade 3/4 non-hematological toxicities included skin rash (10%), nausea (12%), fatigue (10%) and stomatitis (5%).

CONCLUSION

Our trial demonstrates pemetrexed to be active in breast cancer, with manageable toxicity. Activity of pemetrexed did not appear to be adversely affected by prior taxane, 5-fluorouracil or endocrine treatments.

Novel pharmacological approaches in the treatment of breast cancer

Breast cancer is the most common malignancy among women. Novel pharmacological agents, including hormonal, cytotoxic and biological therapies, are currently being developed and tested in clinical trials and may offer patients more treatment options and an improved chance of long-term survival. Signal transduction inhibitors that block endocrine or growth factor pathways have demonstrated exciting antitumour effects in clinical trials. In addition to new chemotherapeutic drugs, numerous biological agents including growth factor receptor-directed monoclonal antibodies and tyrosine kinase inhibitors that target specific molecular lesions are being examined as potential breast cancer treatments.

Review of a promising new agent--pemetrexed disodium

Pemetrexed disodium (ALIMTa, [pemetrexed], LY231514; Eli Lilly and Company; Indianapolis, IN), a novel antifolate antimetabolite with multiple enzyme targets involved in both pyrimidine and purine synthesis, has entered clinical trials due to its favorable pleclinical profile. Many studies utilizing the drug, as a single or combination agent, are currently ongoing, including Phase III trials in mesothelioma, nonsmall cell lung carcinoma (NSCLC) and pancreatic cancer. Promising feasibility and activity data have been obtained with pemetrexed in combination with platinum compounds and gemcitabine. The supplementation with daily oral folate could reduce the incidence of hematologic toxicities while preserving the antitumor activity of pemetrexed.

Pemetrexed (Alimta) and gemcitabine in breast cancer patients previously treated with anthracyclines and taxanes

Gemcitabine (2',2'-difluorodeoxycytidine) is a pyrimidine antimetabolite with broad activity in a variety of solid tumors including breast cancer. Pemetrexed (Alimta) is a novel, multitargeted antifolate that inhibits 3 folate-dependent enzymes, and is also broadly active in a wide variety of solid tumors. In breast cancer, pemetrexed has activity in patients previously treated with anthracyclines and taxanes, and pemetrexed demonstrates preclinical and clinical cytotoxic synergy with gemcitabine. This drug combination is being evaluated in a phase II study for the treatment of metastatic breast cancer patients who have previously received a taxane and an anthracycline.