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PubMed2005

Pemetrexed: a multitargeted antifolate.

BACKGROUND: The US Food and Drug Administration approved pemetrexed in February 2004 for the treatment of malignant pleural mesothelioma (MPM) in combination with cisplatin in patients with unresectable disease or for whom curative surgery is not an option. Pemetrexed is the first agent approved for the treatment of MPM. In August 2004, pemetrexed was approved as a second-line, single-agent treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC). OBJECTIVES: The goals of this article were to summarize the pharmacology, pharmacokinetics, efficacy, and safety of pemetrexed, and to review its current and potential roles in therapy for MPM, NSCLC, and other oncologic conditions. METHODS: Relevant English-language literature was identified through searches of PubMed (1966-December 2004), International Pharmaceutical Abstracts, and the Proceedings of the American Society of Clinical Oncology (January 1995-December 2004). Search terms included pemetrexed, Alimta, MTA, multitargeted antifolate, LY231514, mesothelioma, MPM, non-small cell lung cancer, NSCLC, breast cancer, and pancreatic cancer. In addition to published literature, abstracts and posters presented at national and international scientific meetings were reviewed. RESULTS: Myelosuppression was the predominant dose-limiting toxicity of pemetrexed reported in Phase I studies. Identification of the correlation between poor folate status and increased pemetrexed toxicity in a multivariate analysis led to the requirement of folic acid and vitamin B12 supplementation for patients in all pemetrexed studies, with a resulting noted decrease in pemetrexed toxicity. A single, multicenter, randomized Phase III trial compared the efficacy of pemetrexed in combination with cisplatin versus cisplatin alone in the treatment of MPM. Response rates were 41.3% in the pemetrexed/cisplatin combination and 16.7% with single-agent cisplatin (P < 0.001). The median survival time for the pemetrexed/cisplatin combination was significantly longer at 12.1 months versus 9.3 months for cisplatin alone (P = 0.02). One international, multicenter, randomized Phase III trial in patients with NSCLC compared single-agent pemetrexed versus docetaxel in patients previously treated with chemotherapy. Overall response rates (9.1% and 8.8%) and median survival (8.3 months and 7.9 months) did not differ between pemetrexed and docetaxel (P = 0.105 and P = 0.226, respectively). Hematologic adverse effects-grade 3/4 neutropenia (40.2% vs 5.3%; P < 0.001), febrile neutropenia (12.7% vs 1.9%; P < 0.001), and neutropenic infections (3.3% vs 0%; P = 0.004)-were significantly greater in the docetaxel-treated patients than in the pemetrexed-treated patients, as was alopecia (37.7% vs 6.4%; P < 0.001). Results of an international, multicenter Phase III trial of pemetrexed in combination with gemcitabine conducted in patients with pancreatic cancer indicate that the combination is no more efficacious than single-agent gemcitabine. Results in other disease states are still preliminary. CONCLUSIONS: Pemetrexed is a multitargeted antifolate that has demonstrated antitumor activity in various tumor types as a single agent and in combination with other chemotherapeutic agents. Efficacy for the treatment of MPM in combination with cisplatin has been demonstrated, and approval as a second-line agent in NSCLC was based on response rate as a surrogate end point for survival. The addition of folic acid and vitamin B12 supplementation markedly reduced.

Breast Neoplasms↗
PubMed2002

Interaction of pemetrexed disodium (ALIMTA, multitargeted antifolate) and irradiation in vitro.

PURPOSE: Pemetrexed disodium (Alimta, multitargeted antifolate, LY231514; Eli Lilly and Co., Indianapolis, Indiana) ("pemetrexed") is a new folate antimetabolite with significant antitumor activity. Different from classic antifolates, pemetrexed inhibits several key enzymes of thymidylate and purine synthesis, but a radiosensitizing potential may also be presumed. Therefore, the interaction of pemetrexed and ionizing radiation was studied for in vitro clonogenic survival of different human tumor cell lines. METHODS AND MATERIALS: Human colon (Widr), breast (MCF-7), cervix (Hela), and lung (LXI) carcinoma cells from log-phase cultures were exposed to pemetrexed (2 h) in combination with different radiation doses given 1 h before pemetrexed washout (all cell lines) or at different points of time before or after pemetrexed addition (Widr). Survival curves were analyzed according to the linear-quadratic (LQ) model, and mean inactivation doses (MID) and radiation enhancement ratios were calculated from the survival curve parameters. Cell-cycle progression of serum-stimulated and pemetrexed- or mock-treated Widr cells was monitored by flow cytometry. RESULTS: Radiosensitization was found for all cell lines at moderately toxic pemetrexed exposures (0.05-0.3 microg/ml [106-636 nM]), but this was cell-type dependent and was most pronounced at roughly isotoxic concentrations, for the least pemetrexed-sensitive Widr cells. Enhancement ratios ranged from about 1.2 (MCF-7 and Hela) to 1.8 (Widr), with a tendency to increase with pemetrexed concentration. Little, if any, change of radiosensitization was observed (Widr) when the time of irradiation was varied from 4 h before to 10 h after the beginning of pemetrexed treatment. Cell-cycle progression of serum-stimulated Widr cells was only marginally affected by pemetrexed. CONCLUSIONS: Pemetrexed enhances radiation-induced cell inactivation at moderately toxic exposures and over many hours after drug removal. This effect is not due to disturbed cell-cycle progression, but likely involves an interaction of pemetrexed with long-lived (>4 h) cellular radiation damage and needs to be considered when introducing a combined clinical application.

Antineoplastic Agents↗
PubMed2005

Pemetrexed: new drug. Pleural mesothelioma: a first encouraging trial.

(1) Chemotherapy does not appear to prolong the survival of patients with inoperable pleural mesothelioma, and the tumour response rate barely exceeds 20%. A combination of cisplatin + doxorubicin seems to provide the best response rates. (2) In a trial of second-line docetaxel therapy in patients with non small cell lung cancer, survival was extended by about 3 months compared with palliative care (7.5 versus 4.6 months). (3) Pemetrexed, an antifolate closely related to methotrexate and raltitrexed, has been authorized for use for both conditions. (4) In a randomised single-blind trial involving 456 patients with previously untreated pleural mesothelioma, survival was prolonged by about 3 months by a cisplatin + pemetrexed combination in comparison with cisplatin + placebo (12.1 versus 9.3 months). The respective tumour response rates were 41.3% and 16.7%. This is the only available comparative trial of pemetrexed in patients with mesothelioma. A more appropriate comparator would have been a cisplatin-based regimen such as cisplatin + doxorubicin. (5) A "non inferiority" trial of second-line treatment in 571 patients with locally advanced or metastatic non small cell lung cancer showed no significant difference in median survival time with pemetrexed versus docetaxel (about 8 months with both treatments). However, this trial does not rule out the possibility that pemetrexed is less effective than docetaxel. (6) Supplementation with folic acid and vitamin B12 reduces haematological and gastrointestinal complications associated with the antifolate activity of pemetrexed. (7) Despite this supplementation, more than 15% of patients in the mesothelioma trial developed severe neutropenia, leukopenia or fatigue during cisplatin + pemetrexed therapy. Pemetrexed aggravates the nausea and vomiting provoked by cisplatin, a drug that is highly emetic. (8) The adverse effects of pemetrexed were similar to those of docetaxel in the trial comparing the two drugs. However, neutropenia (5% versus 40%) and febrile neutropenia (2% versus 13%) occurred less frequently with pemetrexed. (9) Patients receiving pemetrexed must be monitored closely for some rare but potentially severe adverse effects; they include angina, myocardial infarction and stroke, liver damage, and bullous skin rash. (10) According to the summary of product characteristics (SPC), pemetrexed therapy must be administered in combination with folic acid and vitamin B12 supplementation in order to reduce haematological toxicity, and also with corticosteroid therapy to reduce the risk of serious skin reactions. (11) In practice, given the absence of a better alternative, and pending the results of a second trial, the cisplatin + pemetrexed combination can be used as a first-line regimen for patients with pleural mesothelioma. However, pemetrexed cannot replace docetaxel in second-line treatment of non small cell lung cancer.

Antineoplastic Agents↗
PubMed2005

The evolving role of pemetrexed (Alimta) in lung cancer.

Pemetrexed (Alimta; Eli Lilly and Co, Indianapolis, IN) is a multitargeted antifolate that inhibits several folate-dependent enzymes that play roles in purine and pyrimidine synthesis. The principal toxicities of pemetrexed are neutropenia, diarrhea, nausea/vomiting, mucositis, and skin rash. These toxicities are more frequent in vitamin-deficient (folate and vitamin B 12 ) patients, and can be ameliorated by the co-administration of folate and vitamin B 12 . The use of prophylactic dexamethasone is also recommended to reduce the frequency of severe skin rash. Pemetrexed has significant single-agent activity in previously treated and untreated patients with non-small cell lung cancer (NSCLC). A recent phase III trial comparing pemetrexed with docetaxel in previously treated NSCLC patients showed equivalent efficacy with less bone marrow toxicity (eg, neutropenia) in the pemetrexed group. These results were pivotal in the approval of pemetrexed for the treatment of refractory NSCLC. Pemetrexed has been combined with the platinums (ie, cisplatin, carboplatin, and oxaliplatin) in NSCLC to yield clinical activity similar to that of other platinum-based doublets. A comparative phase III trial of cisplatin/pemetrexed against cisplatin/gemcitabine (Gemzar; Eli Lilly and Co) is under way. Pemetrexed has also been evaluated in combination with gemcitabine, and although the optimal dose and schedule of this combination has not been defined, clinical activity similar to other nonplatinum-based doublets has been observed. Preliminary evidence suggests that pemetrexed can be combined with thoracic radiation therapy, but more data are needed to evaluate the potential advantage(s) pemetrexed may have in this setting. Pemetrexed/platinum doublets also appear to possess activity in extensive stage small cell lung cancer. A phase II trial of single-agent pemetrexed is under way in both sensitive- and refractory-relapsed small cell lung cancer. Given the activity and excellent tolerability of pemetrexed, further studies in lung cancer are warranted.

Antimetabolites, Antineoplastic↗
PubMed2005

Cytotoxic effects of pemetrexed in gastric cancer cells.

Pemetrexed is a newly developed multitargeted antifolate with promising clinical activity in many solid tumors including gastric cancer. The aim of the present study was to evaluate the cytotoxicity of pemetrexed and its mode of interaction with cisplatin in gastric cancer cell lines, and to identify genes associated with sensitivity to pemetrexed. The cytotoxic activity of pemetrexed was assessed by tetrazolium-based colorimetric assay (MTT assay) and the interaction between pemetrexed and cisplatin was evaluated by the isobologram method. Western immunoblotting and real time RT-PCR analysis of thymidylate synthase (TS), folylpoly-gamma-glutamate synthetase (FPGS) and reduced folate carrier (RFC1) were performed in order to determine whether sensitivity to pemetrexed would be predictable by protein or mRNA expression levels. Pemetrexed was more cytotoxic than 5-fluorouracil, with IC50 between 17 and 310 nM in most of the gastric cancer cell lines examined and the pemetrexed/cisplatin combination resulted in additive or synergistic interaction. The protein expressions of TS, FPGS, and RFC1 were significantly associated with IC50 for 5-fluorouracil, but no such association was found for pemetrexed chemosensitivity. The mRNA expressions of RFC1, FPGS and other target and resistance related genes revealed no significant association with pemetrexed sensitivity. In conclusion, pemetrexed is active against gastric cancer cell lines and the pemetrexed/cisplatin combination showed a synergistic or additive interaction, supporting its clinical use in gastric cancer. Drug sensitivity toward pemetrexed could not be predicted by the expressions of TS, RFC1, or FPGS and we suggest that it is determined by interactions between multiple genes.

Antimetabolites, Antineoplastic↗
PubMed2005

Distribution of the novel antifolate pemetrexed to the brain.

Pemetrexed disodium is a novel antifolate that exhibits potent inhibitory effects on multiple enzymes in folate metabolism. Phase II/III clinical trials have shown that pemetrexed is effective against various solid tumors. Like methotrexate, pemetrexed may be useful in treatment of primary and secondary brain tumors. In this study, we examined the central nervous system (CNS) distribution of pemetrexed and the interaction with an organic anion transport inhibitor indomethacin. Male Wistar rats were administered pemetrexed by either single intravenous bolus or constant intravenous infusion. Unbound pemetrexed in blood and brain was measured by simultaneous arterial blood and frontal cortex microdialysis sampling. In the i.v. bolus experiments, indomethacin was administered by i.v. bolus (10 mg/kg) followed by i.v. infusion (0.1 mg/kg/h) in a crossover manner. In the infusion experiments, the same dose of indomethacin was administered after a steady state was reached for pemetrexed. CNS distributional kinetics was analyzed by compartmental and noncompartmental methods. Both bolus and infusion studies showed that pemetrexed has a limited CNS distribution. The mean area under concentration-time curve (AUC)(brain)/AUC(plasma) ratio of unbound pemetrexed was 0.078 +/- 0.038 in the i.v. bolus study. The pemetrexed steady-state brain-to-plasma unbound concentration ratio after i.v. infusion was 0.106 +/- 0.054. The distributional clearance into the brain was approximately 10% of the clearance out of the brain in both the compartmental and noncompartmental analyses. Indomethacin had no effect on either the brain-to-plasma AUC ratio or the steady-state brain-to-plasma concentration ratio. The distribution of pemetrexed into the brain is limited, and an efflux clearance process, such as an efflux transporter, may be involved.

Animals↗
PubMed2006

Two drug interaction studies evaluating the pharmacokinetics and toxicity of pemetrexed when coadministered with aspirin or Ibuprofen in patients with advanced cancer.

PURPOSE: Pemetrexed is an antimetabolite that is structurally similar to methotrexate. Because nonsteroidal anti-inflammatory drugs (NSAID) impair methotrexate clearance and increase its toxicity, we evaluated the pharmacokinetics and toxicity of pemetrexed when coadministered with aspirin or ibuprofen in advanced cancer patients. EXPERIMENTAL DESIGN: In two independent, randomized, crossover drug interaction studies, cancer patients with a creatinine clearance (CrCl) > or =60 mL/min received an NSAID (aspirin or ibuprofen) with either the first or the second dose of pemetrexed (cycle 1 or 2). Pemetrexed (500 mg/m(2)) was infused i.v. on day 1 of a 21-day cycle, and all patients were supplemented with oral folic acid and i.m. vitamin B(12). Aspirin (325 mg) or ibuprofen (400 mg; 2 x 200 mg) was given orally every 6 hours, starting 2 days before pemetrexed administration, with the ninth and final dose taken 1 hour before infusion. Pemetrexed pharmacokinetics with and without concomitant NSAID treatment were compared for cycles 1 and 2. RESULTS: Data from 27 patients in each study were evaluable for the analysis of pemetrexed pharmacokinetics. Coadministration of aspirin did not alter pemetrexed pharmacokinetics; however, ibuprofen coadministration was associated with a 16% reduction in clearance, a 15% increase in maximum plasma concentration, and a 20% increase in area under the plasma concentration versus time curve but no significant change in V(ss) compared with pemetrexed alone. No febrile neutropenia occurred in any patient, and no increase in pemetrexed-related toxicity was associated with NSAID administration. CONCLUSIONS: Pemetrexed (500 mg/m(2)) with vitamin supplementation is well tolerated and requires no dosage adjustment when coadministered with aspirin (in patients with CrCl > or =60 mL/min) or ibuprofen (in patients with CrCl > or =80 mL/min).

Adult↗
PubMed2007

Pemetrexed disodium for the treatment of malignant pleural mesothelioma: a systematic review and economic evaluation.

OBJECTIVES: To assess the clinical effectiveness and cost-effectiveness of pemetrexed disodium in combination with cisplatin for the treatment of unresectable pleural mesothelioma in chemotherapy-naive patients. DATA SOURCES: Electronic databases were searched up to May 2005. REVIEW METHODS: The systematic review was conducted following accepted guidelines. An assessment of the economic submission received from the manufacturer of pemetrexed was also carried out. This comprised two sections, each employing an economic model. One of these models was then reformulated in order to carry out a separate exploration of economic performance. RESULTS: One randomised controlled trial comparing pemetrexed and cisplatin with cisplatin alone, and involving a total study population of 448 patients, met the inclusion criteria. Pemetrexed in combination with cisplatin in this trial showed a 2.8-month gain in median survival compared with cisplatin alone in an intention-to-treat (ITT) population (12.1 and 9.3 months, respectively, p = 0.020, hazard ratio of 0.77). During the trial, increased reporting of severe toxicity in the pemetrexed arm led to a change in the protocol to add folic acid and vitamin B12 supplementation to therapy. For fully supplemented patients (n = 331) the hazard ratio for median survival in favour of pemetrexed plus cisplatin was also comparable (0.75), but of borderline significance between treatment arms (p = 0.051). The trial inclusion criteria restricted recruitment to those with a Karnofsky performance status of 70 or greater (equivalent to ECOG/WHO 0 or 1 scales more widely used in the UK). Quality of life scores using the Lung Cancer Symptom Scale demonstrated significantly greater improvement for pain and dyspnoea for patients in the combination group compared with those in the cisplatin group. In the ITT population, the incidence of serious toxicities with pemetrexed plus cisplatin was higher compared with cisplatin alone. However, the grade 3/4 toxicities of the combination arm, particularly leucopenia, neutropenia and diarrhoea, were found to be greatly improved by the addition of vitamin B12 and folic acid. The existing published economic literature was very limited. The economic evaluation conducted by the study (and that submitted by the manufacturer) suggested that pemetrexed is unlikely to be considered cost-effective at conventionally accepted thresholds in the UK for all patients, mainly because of the high cost of pemetrexed itself compared with cisplatin. These findings were better for some patient subgroups, e.g. especially for fully supplemented (FS) patients with good performance status (0/1) and advanced disease (AD). These findings seem robust. The estimated cost-effectiveness results were for the FS population, incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY) gained = pound59,600; for the FS with AD population, ICER per QALY = pound47,600; for the FS with performance status 0/1 population, ICER per QALY = pound49,800; and for the FS with performance status 0/1 and AD population, ICER per QALY = pound36,700. CONCLUSIONS: The new therapy examined in this document demonstrates an extension of life expectancy and palliation, as measured by time to progression of disease and other end-points. However, the absolute benefit obtained is small, and it needs to be weighed against the benefits of effective palliative care services. The limited benefit was also at the expense of considerable toxicity to patients. The economic evaluation conducted in this study and that of the manufacturers suggest that pemetrexed is not cost-effective at conventional thresholds for all patients. Cost-effectiveness seems better for some patient subgroups, e.g. especially for patients with good performance status and with advanced diseases, where it is estimated the ICER per QALY would be pound36,700. Given the relatively small number of patients with mesothelioma, albeit increasing, the overall budget impact of pemetrexed would be unlikely to be more than pound5 million per year at present costs. Much more research is needed into the optimum chemotherapy for patients with mesothelioma and a clear definition of what constitutes best supportive care.

Antineoplastic Agents↗
PubMed2006

The effect of a novel transition state inhibitor of methylthioadenosine phosphorylase on pemetrexed activity.

Pemetrexed is a new-generation antifolate inhibitor of thymidylate synthase (TS) and a weaker inhibitor of glycinamide ribonucleotide transformylase (GARFT) required for de novo purine synthesis. Methylthioadenosine phosphorylase (MTAP) salvages purines by releasing adenine from methylthioadenosine and is often deleted in mesothelioma. The current study addresses the effect of MTAP on pemetrexed activity using a highly potent transition state inhibitor of MTAP, MT-DADMe-Immucillin A (ImmA; K(i) = 86 pmol/L) in the MTAP(+) NCI-H28 and MTAP(-) NCI-H2052 mesothelioma cell lines. Based on selective nucleoside protection, TS was found to be the primary pemetrexed target in both cell lines with GARFT inhibition requiring 20- to 30-fold higher pemetrexed concentrations. ImmA had no effect on pemetrexed activity but, when thymidine was added, the pemetrexed IC(50) decreased by a factor of approximately 3 in MTAP(+) H28 cells with no effect in MTAP(-) H2052 cells. Conversely, the transfection of MTAP into H2052 cells increased the pemetrexed IC(50) by nearly 3-fold but only in the presence of thymidine; this was reversed by ImmA. An MTAP-specific short interfering RNA produced a 2-fold decrease in pemetrexed IC(50) in MTAP(+) HeLa cells in the presence of thymidine. These data indicate that suppression of constitutive MTAP has no effect on pemetrexed activity when the primary target is TS. There is a modest salutary effect when the pemetrexed target is GARFT alone.

Cell Line, Tumor↗
PubMed2006

Physical instability of frozen pemetrexed solutions in PVC bags.

BACKGROUND: Pemetrexed is a multitargeted antifolate antineoplastic agent indicated for single-agent use in advanced or metastatic non-small-cell lung cancer and in combination with cisplatin for the treatment of malignant pleural mesothelioma not treatable by surgery. Currently, there is no information on the stability of frozen pemetrexed solutions. OBJECTIVE: To evaluate the stability of pemetrexed admixtures in common infusion solutions frozen at -20 degrees C to determine the drug stability period up to 90 days. METHODS: Triplicate samples of pemetrexed were prepared in concentrations of 2, 10, and 20 mg/mL in dextrose 5% and NaCl 0.9% injection in polyvinyl chloride (PVC) bags. Evaluations for physical and chemical stability were performed initially and over 90 days of frozen storage. Physical stability was assessed using turbidimetric and particulate measurement as well as visual observation. Chemical stability was evaluated by HPLC. RESULTS: All pemetrexed solutions remained chemically stable throughout the 90 day study period, with little or no loss of pemetrexed. However, the pemetrexed admixtures in PVC bags developed large numbers of microparticulates during long-term frozen storage. CONCLUSIONS: Although pemetrexed is chemically stable for 90 days frozen at -20 degrees C, substantial numbers of microparticulates formed in pemetrexed diluted in the infusion solutions in PVC bags upon long-term frozen storage. The avoidance of freezing pemetrexed solutions in PVC bags is therefore warranted.

Antineoplastic Agents↗
PubMed2004

FDA drug approval summaries: pemetrexed (Alimta).

The purpose of this report is to summarize information on pemetrexed (LY231514; MTA; Alimta; Eli Lilly and Company; Indianapolis, IN), a drug recently approved by the U.S. Food and Drug Administration (FDA). The review of the efficacy and safety of pemetrexed is summarized below. Pemetrexed is a pyrrolopyrimidine antifolate. It inhibits thymidylate synthase, glycinamide ribonucleotide formyltransferase, and dihydrofolate reductase. In a single, randomized, single-blind, multicenter phase III trial, the efficacy and safety of pemetrexed combined with cisplatin (Platinol; Bristol-Myers Squibb; Princeton, NJ) were compared with those of single-agent cisplatin in 448 patients with malignant pleural mesothelioma. Two hundred twenty-six patients were randomized to receive pemetrexed and cisplatin, while 222 patients were randomized to receive cisplatin alone. The primary study end point was survival. Median survival times were 12.1 months for the pemetrexed plus cisplatin treated arm and 9.3 months for the cisplatin alone arm. Pemetrexed causes myelosuppression. The most common adverse events were neutropenia, fatigue, leukopenia, nausea, dyspnea, and vomiting. On February 4, 2004, pemetrexed was approved by the FDA in combination with cisplatin for the treatment of patients with malignant pleural mesothelioma whose disease is unresectable or who are otherwise not candidates for curative surgery. The recommended dose of pemetrexed is 500 mg/m(2) administered as an i.v. infusion over 10 minutes on day 1 of each 21-day cycle together with cisplatin at a dose of 75 mg/m(2) infused over 2 hours beginning 30 minutes after the pemetrexed infusion. Patients must receive oral folic acid and vitamin B(12) injections prior to the start of therapy and continue these during therapy to reduce severe toxicities. Patients should also receive corticosteroids with chemotherapy to reduce the risk of skin rashes. Approval was based on superior survival as a clinical benefit.

Adrenal Cortex Hormones↗
PubMed2005

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.

Adolescent↗
PubMed2002

Phase I trials of pemetrexed.

The maximum tolerated dose of the multitargeted antifolate drug pemetrexed is 600 mg/m(2) every 3 weeks in heavily pretreated patients without folic acid supplementation. However, with folic acid supplementation, higher doses have been given without limiting side effects. The dose-limiting toxicities of pemetrexed are neutropenia, asthenia, and thrombocytopenia. Other adverse effects include anemia, anorexia, rash, nausea, vomiting, peripheral edema, diarrhea, mucositis, and reversible elevations of transaminase and creatinine levels. Multiple pemetrexed combination phase I trials have been completed or are underway. Without folic acid supplementation, pemetrexed doses of 400 to 600 mg/m(2)could be safely administered with full therapeutic doses of irinotecan, gemcitabine, cisplatin, carboplatin, oxaliplatin, and 5-fluorouracil. Preliminary data from other ongoing trials (with folic acid and vitamin B(12) supplementation) have similarly shown that pemetrexed doses of at least 400 to 500 mg/m(2) can be safely administered with therapeutic doses of vinorelbine, docetaxel, and paclitaxel. Combination studies of pemetrexed with agents active in breast cancer (doxorubicin, epirubicin, and cyclophosphamide) and chest radiotherapy are also now underway. Adverse effects of these combinations have included neutropenia, anemia, thrombocytopenia, asthenia, vomiting, diarrhea, rash, nausea, anorexia, mucositis, and reversible transaminase elevation. The phase I trials of pemetrexed have consistently shown activity against a broad range of tumor types, including colorectal cancer, pancreatic cancer, breast cancer, non-small cell lung cancer, and mesothelioma. This activity has been noted not only in the combination trials, but when pemetrexed is given as a single agent as well. Pemetrexed is a promising drug. It is active against a broad range of cancers, and it has manageable side effects that seem to be lessened with folic acid and vitamin B(12) supplementation.

Antimetabolites, Antineoplastic↗
PubMed2006

Review of the pemetrexed and gemcitabine combination in patients with advanced-stage non-small cell lung cancer.

Pemetrexed is a new multitargeted antifolate that can be easily administered as a 10-min infusion every 3 weeks. The use of folic acid, vitamin B(12), and corticoid prophylaxis has significantly reduced pemetrexed-induced toxicity. Single-agent pemetrexed has shown antitumor activity in a wide range of solid tumors, including non-small cell lung cancer (NSCLC). Association with vinorelbine, cisplatin, carboplatin, and oxaliplatin have been tried, but the pemetrexed and gemcitabine combination, an easy to administer cisplatin-free doublet, has been documented in many phase 2 trials in the first-line treatment of advanced NSCLC. In vitro cytotoxic assays and phase I studies have defined several schedules of administration for pemetrexed and gemcitabine. The recommended dose is pemetrexed 500 mg/m(2) on day 1 or 8, and gemcitabine 1250 mg/m(2) on day 1 and 8, but it is unknown if pemetrexed should precede or follow gemcitabine and at what time interval. Published studies have failed to show significant differences in overall survival times despites response rates oscillating between 15% and 41%. The main toxicities are neutropenia, fatigue, skin rashes and elevated transaminases and seem to occur with similar rates in the many phase 2 trials. Hopes for the future are in tailored chemotherapy, since molecular markers of sensitivity are available for gemcitabine and pemetrexed, allowing to determinate in the future which patients will be most likely to benefit from the gemcitabine-pemetrexed doublet.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Physical and chemical stability of pemetrexed in infusion solutions.

BACKGROUND: Pemetrexed is a multitargeted, antifolate, antineoplastic agent that is indicated for single-agent use in locally advanced or metastatic non-small-cell lung cancer after prior chemotherapy and in combination with cisplatin for the treatment of malignant pleural mesothelioma not treatable by surgery. Currently, there is no information on the long-term stability of pemetrexed beyond 24 hours. OBJECTIVE: To evaluate the longer-term physical and chemical stability of pemetrexed 2, 10, and 20 mg/mL in polyvinyl chloride (PVC) bags of dextrose 5% injection and NaCl 0.9% injection. METHODS: Triplicate samples of pemetrexed were prepared in the concentrations and infusion solutions required. Evaluations for physical and chemical stability were performed initially and over 2 days at 23 degrees C protected from light and exposed to fluorescent light, and over 31 days of storage at 4 degrees C protected from light. Physical stability was assessed using turbidimetric and particulate measurement as well as visual observation. Chemical stability was evaluated by HPLC. RESULTS: All pemetrexed solutions remained chemically stable, with little or no loss of pemetrexed over 2 days at 23 degrees C, protected from light and exposed to fluorescent light, and over 31 days of storage at 4 degrees C, protected from light. The room temperature samples were physically stable throughout the 48 hour test period. However, pemetrexed admixtures developed large numbers of microparticulates during refrigerated storage exceeding 24 hours. CONCLUSIONS: Pemetrexed is chemically stable for 2 days at room temperature and 31 days refrigerated in dextrose 5% injection and NaCl 0.9% injection. However, substantial numbers of microparticulates may form in pemetrexed diluted in the infusion solutions in PVC bags, especially during longer periods of refrigerated storage. Limiting the refrigerated storage period to the manufacturer-recommended 24 hours will limit particulate formation.

Antineoplastic Agents↗
PubMed2006

Schedule-dependent interactions between pemetrexed and cisplatin in human carcinoma cell lines in vitro.

The combination of pemetrexed and cisplatin shows good clinical activity against mesothelioma and lung cancer. In order to study the potential cellular basis for this, and provide leads as to how to optimize the combination, we studied the schedule-dependent cytotoxic effects of pemetrexed and cisplatin against four human cancer cell lines in vitro. Tumor cells were incubated with pemetrexed and cisplatin for 24 h at various schedules. The combination effects after 5 days were analyzed by the isobologram method. Both simultaneous exposure to pemetrexed and cisplatin for 24 h and sequential exposure to cisplatin for 24 h followed by pemetrexed for 24 h produced antagonistic effects in human lung cancer A549, breast cancer MCF7, and ovarian cancer PA1 cells and additive effects in colon cancer WiDr cells. Pemetrexed for 24 h followed by cisplatin for 24 h produced synergistic effects in MCF7 cells, additive/synergistic effects in A549 and PA1 cells, and additive effects in WiDr cells. Cell cycle analysis of MCF7 and PA1 cells supported these findings. Our results suggest that the simultaneous clinical administration of pemetrexed and cisplatin may be suboptimal. The optimal schedule of pemetrexed in combination with cisplatin at the cellular level is the sequential administration of pemetrexed followed by cisplatin and this schedule is worthy of clinical investigations.

Carcinoma↗
PubMed2004

Pemetrexed in the treatment of advanced non-small-cell lung cancer: a review of the clinical data.

Pemetrexed is a novel multitargeting antimetabolite that has first-line and second-line activity against non-small cell lung cancer (NSCLC). Phase II studies have shown significant efficacy and a favorable toxicity profile of the combination of pemetrexed plus platinum as first-line therapy for NSCLC. Second-line activity against NSCLC was demonstrated in a phase III trial comparing single-agent pemetrexed with docetaxel; in that trial, survival was comparable between these agents but side effects were significantly less for patients who received pemetrexed. Pemetrexed is also an active agent against mesothelioma. A phase III trial comparing pemetrexed plus cisplatin with cisplatin alone showed for the first time a regimen that improves survival in this disease and led to FDA approval of pemetrexed in combination with cisplatin for mesothelioma. As a radiosensitizer, pemetrexed has been well-tolerated when given concurrent with chest radiation, and a phase I study is under way assessing its tolerability in combination with carboplatin in this setting. Pemetrexed is clearly a useful agent in the treatment of thoracic malignancies, and is worthy of further study in combination with other drugs having novel mechanisms of action.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Pemetrexed in malignant pleural mesothelioma.

PURPOSE: This report describes the data and analysis leading to the approval of pemetrexed (LY 231514, MTA, Alimta, Eli Lilly and Co., Indianapolis, IN) by the U.S. Food and Drug Administration (FDA) of a New Drug Application for the treatment of malignant pleural mesothelioma (MPM). EXPERIMENTAL DESIGN: The FDA review of the efficacy and safety of pemetrexed assessed in a randomized clinical trial of 448 patients with unresectable MPM comparing pemetrexed plus cisplatin with cisplatin alone, as well as preclinical pharmacology and chemistry data, are described. The basis for marketing approval is discussed. RESULTS: In one randomized, single-blind, multicenter international trial, 226 patients were randomized to the pemetrexed and cisplatin arm and 222 patients were randomized to cisplatin alone. Median survival times were 12.1 months for pemetrexed and cisplatin and 9.3 months for cisplatin (P = 0.021; hazard ratio, 0.766; 95% confidence interval, 0.61-0.96). Myelosuppression, predominantly neutropenia, was the most common toxicity of pemetrexed plus cisplatin. Other common adverse events were fatigue, leucopenia, nausea, dyspnea, vomiting, chest pain, anemia, thrombocytopenia, and anorexia. CONCLUSIONS: Pemetrexed in combination with cisplatin was approved by the FDA on February 4, 2004 for the treatment of patients with MPM whose disease is either unresectable or who are otherwise not candidates for curative surgery. The recommended dose of pemetrexed is 500 mg/m(2) intra venous infusion over 10 minutes on day 1 of each 21-day cycle in combination with 75 mg/m(2) cisplatin infused over 2 hours beginning 30 minutes after the pemetrexed infusion. Patients must receive oral folic acid and vitamin B(12) injections before the start and during therapy to reduce severe toxicities. Patients should also receive corticosteroids with the chemotherapy to decrease the incidence of skin rash. Approval was based on a demonstration of survival improvement in a single randomized trial. Response rates and time to tumor progression were not included in product labeling because of inconsistencies in assessments among the investigators, independent radiologic reviewers, and the FDA, reflecting the difficulty of radiographic assessments in malignant mesothelioma. Complete prescribing information is available on the FDA Web site at http://www.fda.gov/cder/approval/index.htm.

Adult↗