Prediction of the pharmacokinetics of pemetrexed with a low test dose: A proof-of-concept study.

PURPOSE: Pemetrexed is a cytotoxic drug used for the treatment of lung cancer and mesothelioma. The use of a low test dosing of cytotoxic drugs may aid in dose individualization without causing harm. The aim of this proof-of-concept study was to assess if the pharmacokinetics (PKs) of a test dose could predict the PKs of a therapeutic pemetrexed dose. METHODS: Ten patients received both a low test dose (100 µg) and a therapeutic dose of pemetrexed after which plasma concentrations pemetrexed were measured. PK analysis was performed by means of nonlinear mixed-effects modelling. The predictive performances of test dose clearance and renal function towards a therapeutic dose were assessed. RESULTS: The PKs of a pemetrexed test dose were best described by a one-compartment model with linear elimination. A high variability in the administered dose was observed for the test dose, but not for the therapeutic dose. A statistically significant correlation between test dose clearance and therapeutic dose clearance was observed (Spearman's rho: 0.758, P = 0.02). The predictive performance of test dose clearance was worse than renal function: mean predictive error (+95% confidence interval [CI]) 53.9% (50.1-57.6%) vs 19.4% (12.4-26.4%) and normalized root-mean square error (+95% CI) 57.8% (30.5-85.1%) vs 25.7% (20.3-31.0%). CONCLUSION: We show that test dosing of pemetrexed is feasible, but there seems no added value for a low test dosing in the dose individualization of pemetrexed.

Highly sensitive quantification of pemetrexed in human plasma using UPLC-MS/MS to support microdosing studies.

Pemetrexed is an antifolate drug approved for the treatment of non-small-cell lung cancer and mesothelioma. Assessing pemetrexed pharmacokinetics after administration of a microdose (100 µg) may facilitate drug-drug interaction and dose individualization studies with cytotoxic drugs, without causing harm to patients. Therefore, a highly sensitive bioanalytical assay is required. A reversed-phase ultra-high performance liquid chromatography method was developed to determine pemetrexed concentrations in human ethylenediaminetetraacetic acid-plasma after microdosing. [13 C5 ]-Pemetrexed was used as the internal standard. The sample preparation involved solid-phase extraction from plasma. Detection was performed using MS/MS in a total run time of 9.5 min. The assay was validated over the concentration range of 0.0250-25.0 µg/L pemetrexed. The average accuracies for the assay in plasma were 96.5 and 96.5%, and the within-day and between-day precision in coefficients of variations was <8.8%. Extraction recovery was 59 ± 1 and 55 ± 5% for pemetrexed and its internal standard. Processed plasma samples were stable for 2 days in a cooled autosampler at 10°C. The assay was successfully applied in a pharmacokinetic curve, which was obtained as a part of an ongoing clinical microdosing study.

Toxicity of pemetrexed during renal impairment explained-Implications for safe treatment.

Pemetrexed is an important component of first line treatment in patients with non-squamous non-small cell lung cancer. However, a limitation is the contraindication in patients with renal impairment due to hematological toxicity. Currently, it is unknown how to safely dose pemetrexed in these patients. The aim of our study was to elucidate the relationship between pemetrexed exposure and toxicity to support the development of a safe dosing regimen in patients with renal impairment. A population pharmacokinetic/pharmacodynamic analysis was performed based on phase II study results in three patients with renal dysfunction, supplemented with data from 106 patients in early clinical studies. Findings were externally validated with data of different pemetrexed dosing regimens. Alternative dosing regimens were evaluated using the developed model. We found that pemetrexed toxicity was driven by the time above a toxicity threshold concentration. The threshold for vitamin-supplemented patients was 0.110 mg/mL (95% CI: 0.092-0.146 mg/mL). It was observed that in patients with renal impairment (estimated glomerular filtration rate [eGFR]: <45 mL/min) the approved dose of 500 mg/m2 would yield a high probability of severe neutropenia in the range of 51.0% to 92.6%. A pemetrexed dose of 20 mg for patients (eGFR: 20 mL/min) is shown to be neutropenic-equivalent to the approved dose in patients with adequate renal function (eGFR: 90 mL/min), but would result in an approximately 13-fold lower area under the concentration-time curve. The pemetrexed exposure-toxicity relationship is explained by a toxicity threshold and substantially different from previously thought. Without prophylaxis for toxicity, it is unlikely that a therapeutic dose can be safely administered to patients with renal impairment.

Preparation and Evaluation of Stearylamine-Bearing Pemetrexed Disodium-Loaded Cationic Liposomes In Vitro and In Vivo.

Pemetrexed disodium (PMX) stands out in the treatment of non-small cell lung cancer (NSCLC), but with short half-life and toxic side effects. This study was to design cationic liposomes for targeting delivery PMX to the lungs. The PMX cationic liposome was prepared by thin-film hydration using stearylamine (SA) as the positive component of charge-regulating charge. Then, the PMX cationic liposome (SA-PMX-Lips) was characterized by particle size, morphology, entrapment efficiency (EE), and drug loading (DL). Finally, the drug release behavior in vitro, the pharmacokinetic study, and tissue distribution of SA-PMX-Lips were evaluated separately, with PMX solution (PMX-Sol) and PMX liposome (PMX-Lips) as the control. According to results, SA-PMX-Lips were spherical and the particle size was 219.7 ± 4.97 nm with a narrow polydispersity index (PDI) (0.231 ± 0.024) and a positive zeta potential 22.2 ± 0.52 mV. Its EE was 92.39 ± 1.94% and DL was 9.15 ± 0.07%. The results of in vitro and in vivo experiments showed that SA-PMX-Lips released slowly, prolonged retention time and increased the value of AUC. More notably, SA-PMX-Lips could improve the accumulation of drugs in the lungs and the relative uptake rate (Re) was 2.35 in the lungs, which indicated its lung targeting. In summary, SA-PMX-Lips showed the potential for the effective delivery of PMX and the treatment of NSCLC.

Cytotoxicity study and influence of SBA-15 surface polarity and pH on adsorption and release properties of anticancer agent pemetrexed.

Mesoporous material SBA-15 was functionalized with different polar and nonpolar groups: 3-aminopropyl, (SBA-15-NH2), 3-isocyanatopropyl (SBA-15-NCO), 3-mercaptopropyl (SBA-15-SH), methyl (SBA-15-CH3) and phenyl (SBA-15-Ph). The resulting surface grafted materials were investigated as matrices for controlled drug delivery. Anticancer agent, pemetrexed (disodium pemetrexed heptahydrate) was selected as a model drug and loaded in the unmodified and functionalized SBA-15 materials. Materials were characterized by elemental analysis, infrared spectroscopy, transmission electron microscopy, nitrogen adsorption/desorption analysis, small angle X-ray scattering, powder X-ray diffraction, solid state NMR spectroscopy and thermogravimetry. It was shown that surface modification has an impact on both encapsulated drug amount and release properties. Release experiments were performed into two media with different pH: simulated body fluid (pH = 7.4) and simulated gastric fluid (pH = 2). In general, the effect of pH was reflected by the lower release of pemetrexed under acidic conditions (pH = 2) compared to slightly alkaline saline environment (pH = 7.4). The release rate of pemetrexed from propylamine-, propylisocyanate- and phenyl-modified SBA-15 was found to be effectively controlled by intermolecular interactions as compared to that from pure SBA-15, SBA-15-SH, and SBA-15-CH3, that evidenced a steady and similar release. The highest release was observed for methyl-functionalized material whose hydrophobic surface accelerates the pemetrexed release. The data obtained from release studies were fitted using various kinetic models to determine the pemetrexed release mechanism and its release rate. The best correlations were found for Korsmeyer-Peppas and Higuchi models. Moreover, the theoretical three-parameter model for drug release kinetic was applied to calculate the strength of drug-support interactions. The in vitro cell study was performed on SKBR3 cancer cells and obtained results demonstrated that the modification of the mesoporous silica material by grafted polar/nonpolar groups may significantly affect the compatibility of this material with cells, drug release from this material and subsequent biological activity of PEM.

A limited sampling schedule to estimate individual pharmacokinetics of pemetrexed in patients with varying renal functions.

PURPOSE: Pemetrexed is a widely used cytostatic agent with an established exposure-response relationship. Although dosing is based on body surface area (BSA), large interindividual variability in pemetrexed plasma concentrations is observed. Therapeutic drug monitoring (TDM) can be a feasible strategy to reduce variability in specific cases leading to potentially optimized pemetrexed treatment. The aim of this study was to develop a limited sampling schedule (LSS) for the assessment of pemetrexed pharmacokinetics. METHODS: Based on two real-life datasets, several limited sampling designs were evaluated on predicting clearance, using NONMEM, based on mean prediction error (MPE %) and normalized root mean squared error (NRMSE %). The predefined criteria for an acceptable LSS were: a maximum of four sampling time points within 8 h with an MPE and NRMSE ≤ 20%. RESULTS: For an accurate estimation of clearance, only four samples in a convenient window of 8 h were required for accurate and precise prediction (MPE and NRMSE of 3.6% and 5.7% for dataset 1 and of 15.5% and 16.5% for dataset 2). A single sample at t = 24 h performed also within the criteria with MPE and NRMSE of 5.8% and 8.7% for dataset 1 and of 11.5% and 16.4% for dataset 2. Bias increased when patients had lower creatinine clearance. CONCLUSIONS: We presented two limited sampling designs for estimation of pemetrexed pharmacokinetics. Either one can be used based on preference and feasibility.

Intestinal transport mechanism and in vivo anticancer efficacy of a solid oral formulation incorporating an ion-pairing complex of pemetrexed with deoxycholic acid derivative.

OBJECTIVE: The rational combination of immunotherapy with standard chemotherapy shows synergistic clinical activities in cancer treatment. In the present study, an oral powder formulation of pemetrexed (PMX) was developed to enhance intestinal membrane permeability and investigate its application in metronomic chemotherapy in combination with immunotherapy. METHODS: PMX was ionically complexed with a bile acid derivative (Nα-deoxycholyl-l-lysyl-methylester; DCK) as a permeation enhancer and mixed with dispersing agents, such as poloxamer 188 (P188) and Labrasol, to form an amorphous oral powder formulation of PMX/DCK (PMX/DCK-OP). RESULTS: The apparent permeability (Papp) of PMX/DCK-OP across a Caco-2 cell monolayer was 2.46- and 8.26-fold greater than that of PMX/DCK and free PMX, respectively, which may have been due to the specific interaction of DCK with bile acid transporters, as well as the alteration of membrane fluidity due to Labrasol and P188. Furthermore, inhibition of bile acid transporters by actinomycin D in Caco-2 cell monolayers decreased the Papp of PMX/DCK-OP by 75.4%, suggesting a predominant role of bile acid transporters in the intestinal absorption of PMX/DCK-OP. In addition, caveola/lipid raft-dependent endocytosis, macropinocytosis, passive diffusion, and paracellular transport mechanisms significantly influenced the permeation of PMX/DCK-OP through the intestinal membrane. Therefore, the oral bioavailability of PMX/DCK-OP in rats was 19.8%±6.93%, which was 294% higher than that of oral PMX. Moreover, an in vivo anticancer efficacy study in B16F10 cell-bearing mice treated with a combination of oral PMX/DCK-OP and intraperitoneal anti-PD1 exhibited significant suppression of tumor growth, and the tumor volume was maximally inhibited by 2.03- and 3.16-fold compared to the oral PMX/DCK-OP and control groups, respectively. CONCLUSION: These findings indicated the therapeutic potential of a combination of low-dose oral chemotherapy and immunotherapy for synergistic anticancer efficacy.

Pemetrexed exposure predicts toxicity in advanced non-small-cell lung cancer: A prospective cohort study.

BACKGROUND: We explored whether total exposure to pemetrexed predicts effectiveness and toxicity in advanced non-small-cell lung cancer (NSCLC). Furthermore, we investigated alternative dosing schedules. METHODS: In this prospective cohort study, patients with advanced NSCLC receiving first- or second-line pemetrexed(/platinum) were enrolled. Plasma sampling was performed weekly (cyclePK) and within 24 h (24hPK) after pemetrexed administration. With population pharmacokinetic/pharmacodynamic modelling, total exposure to pemetrexed during cycle 1 (area under the curve during chemotherapy cycle 1 [AUC1]) was estimated and related to progression-free survival (PFS)/overall survival (OS). We compared mean AUC1 (mg·h/L) in patients with and without severe chemotherapy-related adverse events (AEs) during total treatment. Second, different dosing schedules were simulated to minimise the estimated variability (coefficient of variation [CV]) of AUC. RESULTS: For 106 of 165 patients, concentrations of pemetrexed were quantified (24hPK, n = 15; cyclePK, n = 106). After adjusting for prognostic factors, sex, disease stage and World Health Organisation performance score, AUC1 did not predict PFS/OS in treatment-naive patients (n = 95) (OS, hazard ratio [HR] = 1.05, 95% confidence interval [CI]: 1.00-1.11; PFS, HR = 1.03, 95% CI: 0.98-1.08). Patients with severe chemotherapy-related AEs (n = 55) had significantly higher AUC1 values than patients without them (n = 51) (226 ± 53 vs 190 ± 31, p < 0.001). Compared with body surface area-based dosing (CV: 22.5%), simulation of estimated glomerular filtration rate (eGFR)-based dosing (CV 18.5%) and fixed dose of 900 mg with 25% dose reduction, if the eGFR<60 mL/min (CV: 19.1%), resulted in less interindividual variability of AUC. CONCLUSIONS: Higher exposure to pemetrexed does not increase PFS/OS but is significantly associated with increased occurrence of severe toxicity. Our findings suggest that fixed dosing reduces interpatient pharmacokinetic variability and thereby might prevent toxicity, while preserving effectiveness.

Luminespib plus pemetrexed in patients with non-squamous non-small cell lung cancer.

BACKGROUND: Luminespib (AUY922) is a second-generation heat shock protein 90 (HSP90) inhibitor with demonstrated activity in non-small cell lung cancer (NSCLC). Since luminespib reduces levels of dihydrofolate reductase (DHFR), a key enzymatic target of pemetrexed, we assessed the safety and tolerability of luminespib in combination with pemetrexed in patients with previously treated metastatic non-squamous non-small cell lung cancer (NSCLC). We also sought to study the pharmacokinetics and correlate tumor dihydrofolate reductase (DHFR) expression with clinical response. METHODS: Patients received weekly luminespib at either 40 mg/m2, 55 mg/m2, or 70 mg/m2 according to a standard 3 + 3 dose-escalation design along with pemetrexed at 500 mg/m2 followed by an expansion at the maximum tolerated dose (MTD). RESULTS: Two-dose limiting toxicities (DLTs) were experienced in the 70 mg/m2 cohort, therefore the MTD was determined to be 55 mg/m2. 69% (N = 9) of patients experienced ophthalmologic toxicity related to luminespib. Maximum serum concentration (Cmax) of luminespib was associated with increased grade 2 drug related adverse events (DRAEs) (rs = 0.74, P < 0.01), with volume of distribution (VD) inversely associated with the number of DRAEs (rs = - 0.81, P = 0.004) and ophthalmologic related DRAEs (rs = - 0.65, P = 0.04). The best response was partial response in one patient for 20 months, prior to expiration of all luminespib. Amongst patients treated at the MTD, the objective response rate was 14%. CONCLUSION: In patients with previously treated metastatic NSCLC, the MTD of luminespib in combination with pemetrexed was 55 mg/m2 per week. The combination of luminespib and pemetrexed demonstrated clinical activity. Tolerability of luminespib with pemetrexed is limited by ocular toxicity.

Population Pharmacokinetics of Pemetrexed in Adult Non-Small Cell Lung Cancer in Indian Patients.

The objective of the study was to develop a population pharmacokinetic model of pemetrexed and identify factors contributing to variability in exposure in Indian patients. Plasma samples were obtained from a cohort of 85 patients following 500 mg/m2 intravenous infusion and population pharmacokinetic analysis was performed using NONMEM (version 7.3.0). The stochastic approximation expectation maximization method was used to estimate parameters. The full covariate model approach was used by specifying clinically meaningful covariates a priori. Credible intervals obtained using Markov chain Monte Carlo Bayesian analysis were used to reduce the full covariate model by eliminating the covariates whose CI included the null. Model qualification was performed using visual predictive check and bootstrap. The final population parameter estimates and relative standard error for clearance (CL) was 3.3 L/h (10.8), central volume of distribution (V1) was 5.2 L (7.8), peripheral volume of distribution (V2) was 5.9 L (14.5) and intercompartmental clearance (Q) was 6.8 L/h (14.3). A large between-subject variability (50%-108% coefficient of variation) was observed in pharmacokinetic parameters. The percent coefficient of variation for the area under the plasma concentration-time curve from time zero to infinity was 72% and for maximum concentration was 68.25%. Diagnostic plots showed no major bias in the model. The final model included V1, V2, and Q scaled to body surface area raised to a fixed exponent of 1. Creatinine clearance and sex on clearance and albumin on V1 were statistically significant covariates based on Bayesian credible interval. However, traditional bootstrap resulted in a 95% confidence interval of the sex effect parameter including null. Given the size and nonsignificant sex effect in traditional bootstrap, it is considered clinically not significant.

Optimal Scheduling of Bevacizumab and Pemetrexed/Cisplatin Dosing in Non-Small Cell Lung Cancer.

Bevacizumab-pemetrexed/cisplatin (BEV-PEM/CIS) is a first-line therapeutic for advanced nonsquamous non-small cell lung cancer. Bevacizumab potentiates PEM/CIS cytotoxicity by inducing transient tumor vasculature normalization. BEV-PEM/CIS has a narrow therapeutic window. Therefore, it is an attractive target for administration schedule optimization. The present study leverages our previous work on BEV-PEM/CIS pharmacodynamic modeling in non-small cell lung cancer-bearing mice to estimate the optimal gap in the scheduling of sequential BEV-PEM/CIS. We predicted the optimal gap in BEV-PEM/CIS dosing to be 2.0 days in mice and 1.2 days in humans. Our simulations suggest that the efficacy loss in scheduling BEV-PEM/CIS at too great of a gap is much less than the efficacy loss in scheduling BEV-PEM/CIS at too short of a gap.

Pharmacokinetically-guided dosing of pemetrexed in a patient with renal impairment and a patient requiring hemodialysis.

OBJECTIVES: Pemetrexed is indicated for non-small cell lung cancer and mesothelioma. Dosing is based on body surface are (BSA), while renal function is the only determinant for exposure and thus toxicity. BSA-based dosing introduces large variability in exposure and may lead to (hemato)toxicity in patients with impaired renal function. Therefore, pemetrexed is contraindicated in renal impairment. The presented cases provide proof-of-concept for pharmacokinetically-guided dosing of pemetrexed in a haemodialysis patient and a patient with mild renal impairment. METHODS: The pharmacokinetic target was an area under the concentration-time curve (AUC) of 123-205 mg·h/L. Using a previously developed population pharmacokinetic model, individual pharmacokinetics were estimated. RESULTS: Both patients had an exposure above target after the initial dose, but a proportional dose reduction resulted in a therapeutic exposure in both patients (185 and 166 mg·h/L, respectively), that was well-tolerated. Interestingly, a threefold increase in systemic clearance of pemetrexed was observed during hemodialysis (from 1.00 L/h to 3.01 L/h), which approximates the population clearance of pemetrexed. CONCLUSION: Altogether, we showed that pharmacokinetically-guided dosing of pemetrexed may be a feasible strategy for patients with lung cancer and renal impairment.

Combining Albumin-Binding Properties and Interaction with Pemetrexed to Improve the Tissue Distribution of Radiofolates.

Folic-acid-based radioconjugates have been developed for nuclear imaging of folate receptor (FR)-positive tumors; however, high renal uptake was unfavorable in view of a therapeutic application. Previously, it was shown that pre-injection of pemetrexed (PMX) increased the tumor-to-kidney ratio of radiofolates several-fold. In this study, PMX was combined with the currently best performing radiofolate ([177Lu]cm13), which is outfitted with an albumin-binding entity. Biodistribution studies were carried out in mice bearing KB or IGROV-1 tumor xenografts, both FR-positive tumor types. SPECT/CT was performed with control mice injected with [177Lu]folate only and with mice that received PMX in addition. Control mice showed high uptake of radioactivity in KB and IGROV-1 tumor xenografts, but retention in the kidneys was also high, resulting in tumor-to-kidney ratios of ~0.85 (4 h p.i.) and ~0.60 (24 h p.i.) or ~1.17 (4 h p.i.) and ~1.11 (24 h p.i.) respectively. Pre-injection of PMX improved the tumor-to-kidney ratio to values of ~1.13 (4 h p.i.) and ~0.92 (24 h p.i.) or ~1.79 (4 h p.i.) and ~1.59 (24 h p.i.), respectively, due to reduced uptake in the kidneys. It was found that a second injection of PMX­3 h or 7 h after administration of the radiofolate­improved the tumor-to-kidney ratio further to ~1.03 and ~0.99 or ~1.78 and ~1.62 at 24 h p.i. in KB and IGROV-1 tumor-bearing mice, respectively. SPECT/CT scans readily visualized the tumor xenografts, whereas accumulation of radioactivity in the kidneys was reduced in mice that received PMX. In this study, it was shown that PMX had a positive impact in terms of reducing the kidney uptake of albumin-binding radiofolates; hence, the administration of PMX resulted in ~1.3⁻1.7-fold higher tumor-to-kidney ratios. This is, however, a rather moderate effect in comparison to the previously shown effect of PMX on conventional radiofolates (without albumin binder), which led to 5⁻6-fold increased tumor-to-kidney ratios. An explanation for this result may be the different pharmacokinetic profiles of PMX and long-circulating radiofolates, respectively. Despite the promising potential of this concept, it is believed that a clinical translation would be challenging, particularly when PMX had to be injected more than once.

Oral pemetrexed facilitates low-dose metronomic therapy and enhances antitumor efficacy in lung cancer.

There is a growing interest in preclinical research to consider low-dose metronomic chemotherapy as antiangiogenic cancer treatment. Oral metronomic therapy, in particular, has shown much promise with its ease of daily administration and higher therapeutics window. In that regard, we developed oral pemetrexed using the physical complex with the bile acid enhancers (DCK). In a caco-2 permeability study, the oral pemetrexed/DCK complex had significantly higher drug uptake, and inhibited efflux transporter activity as well. We further observed that the mechanism of oral drug uptake was related to transcellular along with bile acid transporter mediated pathways. The oral administration of drug complex in rats revealed high bioavailability (22.37%) and extended mean residence time. Using SCC7 and A549 xenograft models, we demonstrated that antitumor effects from daily oral metronomic pemetrexed significantly reduced tumor in a dose-dependent manner. The antitumor activity of oral pemetrexed/DCK complex plus cisplatin was superior to both monotherapies. The xenograft study also revealed that oral metronomic therapy markedly reduced microvessel density, proliferation and increased apoptosis in the tumor tissues. Oral metronomic doses were significantly correlated with the elevation of plasma deoxyuridine level, an essential biomarker for pemetrexed therapy. One-month toxicity study confirmed that daily dosing of oral pemetrexed is safe by investigating apoptosis in the gut tissues from mice. Moreover, we analyzed different biochemical parameters and enzymes from the blood to prove that our newly developed oral pemetrexed complex is well tolerated.

Enhanced oral absorption of pemetrexed by ion-pairing complex formation with deoxycholic acid derivative and multiple nanoemulsion formulations: preparation, characterization, and in vivo oral bioavailability and anticancer effect.

OBJECTIVE: The current study sought to design an oral delivery system of pemetrexed (PMX), a multitargeted antifolate antimetabolite, by enhancing its intestinal membrane permeability. MATERIALS AND METHODS: PMX was ionically complexed with a permeation enhancer such as Nα-deoxycholyl-l-lysyl-methylester (DCK) and prepared as an amorphous solid dispersion by mixing with dispersants such as 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and poloxamer 188 (P188), forming an HP-beta-CD/PMX/DCK/P188; the complex was incorporated into multiple water-in-oil-in-water nanoemulsions in a supersaturated state (HP-beta-CD/PMX/DCK/P188-NE). RESULTS: After complex formation, the partition coefficient and in vitro membrane permeability of PMX were markedly increased, but it showed similar cytotoxic and inhibitory effects on cancer cell proliferation/migration. Furthermore, the intestinal membrane permeability and epithelial cell uptake of PMX were synergistically improved after HP-beta-CD/PMX/DCK/P188 was incorporated into a nanoemulsion with a size of 14.5±0.45 nm. The in vitro permeability of HP-beta-CD/PMX/DCK/P188-NE across a Caco-2 cell monolayer was 9.82-fold greater than that of free PMX, which might be attributable to the partitioning of PMX to the epithelial cells being facilitated via specific interaction of DCK with bile acid transporters, as well as the enhanced lipophilicity accompanied by surfactant-induced changes in the intestinal membrane structure and fluidity. Therefore, the oral bioavailability of HP-beta-CD/PMX/DCK/P188-NE in rats was evaluated as 26.8%±2.98% which was 223% higher than that of oral PMX. Moreover, oral HP-beta-CD/PMX/DCK/P188-NE significantly suppressed tumor growth in Lewis lung carcinoma cell-bearing mice, and the tumor volume was maximally inhibited by 61% compared with that in the control group. CONCLUSION: These results imply that HP-beta-CD/PMX/DCK/P188-NE is an effective and promising delivery system for enhancing the oral absorption of PMX. Thus, there is the potential for new medical applications, including applications in metronomic cancer treatment.

Lung cancer specific and reduction-responsive chimaeric polymersomes for highly efficient loading of pemetrexed and targeted suppression of lung tumor in vivo.

Lung cancer is one of the worldwide leading and fast-growing malignancies. Pemetrexed disodium (PEM, Alimta®), a small hydrophilic drug, is currently used for treating lung cancer patients. However, PEM suffers from issues like fast elimination, low bioavailability, poor tumor cell selectivity and penetration. Here, we report on lung cancer specific CSNIDARAC (CC9) peptide-functionalized reduction-responsive chimaeric polymersomes (CC9-RCPs) for efficient encapsulation and targeted delivery of PEM to H460 human lung cancer cells in vitro and in vivo. PEM-loaded CC9-RCPs (PEM-CC9-RCPs) was obtained from co-self-assembly of poly(ethylene glycol)-b-poly(trimethylene carbonate-co-dithiolane trimethylene carbonate)-b-polyethylenimine (PEG-P(TMC-DTC)-PEI) and CC9-functionalized PEG-P(TMC-DTC) in the presence of PEM followed by self-crosslinking. PEM-CC9-RCPs displayed an optimal CC9 density of 9.0% in targeting H460 cells, a high PEM loading content of 14.2 wt%, a small hydrodynamic size of ca. 60 nm and glutathione-triggered PEM release. MTT assays showed that PEM-CC9-RCPs was 2.6- and 10- fold more potent to H460 cells than the non-targeting PEM-RCPs and free PEM controls, respectively. Interestingly, PEM-CC9-RCPs exhibited 22-fold longer circulation time and 9.1-fold higher accumulation in H460 tumor than clinical formulation Alimta®. Moreover, CC9-RCPs showed obviously better tumor penetration than RCPs. Remarkably, PEM-CC9-RCPs at 12.5 mg PEM equiv./kg effectively suppressed growth of H460 xenografts and significantly prolonged mouse survival time as compared to PEM-RCPs and Alimta® controls. These lung cancer specific and reduction-responsive chimaeric polymersomes provide a unique pemetrexed nanoformulation for targeted lung cancer therapy. STATEMENT OF SIGNIFICANCE: Multitargeted antifolate agent pemetrexed (PEM, Alimta®) is currently used for treating lung cancer patients and has low side-effects. However, PEM suffers from issues like fast elimination, low bioavailability, poor tumor cell selectivity and penetration. Scarce work on targeted delivery of PEM has been reported, partly because most conventional nanocarriers show a low and instable loading for hydrophilic, negatively charged drugs like PEM. Herewith, we report on lung cancer specific CSNIDARAC (CC9) peptide-functionalized reduction-responsive chimaeric polymersomes (CC9-RCPs) which showed efficient PEM encapsulation (14.2 wt%, 60 nm) and targeted delivery of PEM to H460 human lung cancer cells, leading to effective suppression of H460 tumor xenografts and significantly prolonged survival rates of mice than Alimta®. To the best of our knowledge, this represents a first report on targeted nanosystems that are capable of efficient loading and targeted delivery of PEM to lung tumors.

Unusually prolonged pemetrexed cytotoxicity in a patient with a lung adenocarcinoma: a case report.

BACKGROUND: We describe a case of pemetrexed toxicities related to reabsorption by an ileal neobladder, which caused prolonged hematotoxicity and nephrotoxicity. CASE PRESENTATION: A 59-year-old white man was diagnosed with metastatic wild-type adenocarcinoma of the upper lobe of his right lung. After a first cycle of cisplatin and pemetrexed, he had unusually prolonged aplasia and acute kidney injury. The prolonged aplasia was caused by pemetrexed reabsorption by the ileal mucosa of the neobladder as pemetrexed was eliminated renally in an active form and is partly lipophilic. CONCLUSIONS: Pemetrexed may be reabsorbed by the ileal mucosa of the neobladder because of its hydrophobic structure and renal excretion in its active form. Acute urinary retention may maintain this phenomenon. Published data excluded a potential role for cisplatin in this toxicity; furthermore, we could not assess pemetrexed concentrations in the blood or urine as these assay techniques are not validated. Thus, care is needed when giving chemotherapy to patients with a neobladder.

A Comparative Pharmacokinetic Study of 2 Pemetrexed Formulations in Indian Adult Chemonaive Patients With Adenocarcinoma Stage III/IV Non-Small Cell Lung Cancer.

The study aimed to compare the pharmacokinetics of 2 pemetrexed formulations (Pemgem, Dr. Reddy's Laboratories w.r.t; Alimta, Eli Lilly) in adult chemonaive subjects with adenocarcinoma stage III/IV non-small cell lung cancer. All patients received 500 mg/m2 pemetrexed (Alimta or Pemgem) as a 10-minute infusion on day 1 of a 21-day cycle. Plasma pemetrexed concentrations were determined on day 1 of cycle 1. Area under the concentration-time curve (AUC0-inf ) and the maximum plasma concentration (Cmax ) were estimated using noncompartment analysis and compared between the 2 arms. Forty-eight patients were enrolled in the study, 24 in each arm. Patient demographics were comparable in both arms. Mean AUC0-inf for the generic and innovator formulations was 218.2 ± 19.18 and 223.6 ± 34.24 µg·h/mL, respectively, and mean Cmax was 119 ± 13.44 and 113 ± 7.26 µg/mL, respectively. Volume of distribution of pemetrexed was 17.5 and 27.6 L, clearance was 4.2 versus 4.72 L/h, and half-life was 4.3 and 4.83 h in the 2 arms respectively. Both formulations showed comparable response rates (objective response of 45% versus 50% in the Pemgem and Alimta arms, respectively) and similar safety profiles. To conclude, Pemgem showed pharmacokinetic and safety profiles similar to Alimta. Substitution of Alimta with Pemgem will be cost-effective and likely to yield comparable efficacy.

Cost-effectiveness of pemetrexed in combination with cisplatin as first line treatment for patients with advanced non-squamous non-small-cell lung cancer in Spain / Coste-eficacia del pemetrexed en combinación con cisplatino como tratamiento de primera línea en pacientes con cáncer de pulmón avanzado no microcítico ni escamoso en España

Introduction: Lung cancer is the third most frequent neoplastic tumour in Spain, with around 27000 new cases diagnosed per year; 80-95% of these are non-small-cell cancer (NSCLC), and the majority of cases are diagnosed in advanced stages of the disease, and for this reason it is one of the oncologic conditions with higher mortality rates (21.4% mean survival at 5 years). The main treatment regimens used for first-line treatment of NSCLC are: cisplatin/pemetrexed (cis/pem), cisplatin/gemcitabine/bevacizumab (cis/gem/bev), and carboplatin/paclitaxel/ bevacizumab (carb/pac/bev). The objective of this study was to evaluate the cost-effectiveness ratio of antineoplastic 1st line NSCLC treatment regimens, from the point of view of hospital management. Methodology: A cost-efficacy mathematical model was prepared, based on a decision tree. The efficacy variable was Progression Free Survival, obtained from the PARAMOUNT, AVAIL and SAIL Phase III clinical trials. The study was conducted from the perspective of the hospital management, considering only the direct costs of drug acquisition. A deterministic sensitivity analysis was conducted to confirm the robustness of outcomes. Results: The PFS obtained in clinical trials with cis/pem, cis/ gem/bev and carb/pac/bev was: 6.9, 6.7 and 6.2 months, respectively. Based on our model, the mean cost of treatment per patient for these regimens was: 19942 Euros, 15594 Euros and 36095 Euros, respectively. The incremental cost-effectiveness ratio per month of additional PFS between cis/pem and cis/gem/bev was 19303 Euros . Estimating a 30% reduction in acquisition costs for pemetrexed (Alimta®Eli Lilly Nederland B.V.), due to the forthcoming launch of generic medications, the cis/pem treatment would become the predominant alternative for 1st line treatment of NSCLC patients, by offering the best health results at a lower cost (AU)

Introducción: El cáncer de pulmón es la tercera neoplasia tumoral más frecuente en España, con unos 27.000 nuevos casos/ año, de los que el 80-85% son de etiología no microcítica (NSCLC) y en la mayoría de los casos diagnosticados en estadíos avanzados de la enfermedad, razón por la que es uno de los procesos oncológicos con mayores tasas de mortalidad (supervivencia media a los 5 años del 21,4%). Los principales esquemas de primera línea utilizados en el tratamiento del NSCLC son: cisplatino/pemetrexed (cis/pem), cisplatino/gemcitabina/ bevacizumab (cis/gem/bev), y carboplatino/paclitaxel/bevacizumab (carbo/pac/Bev). El objetivo del presente trabajo consistirá en realizar un análisis para estimar el ratio coste-eficacia de los esquemas antineoplásicos de primera línea en el tratamiento del NSCLC, desde la perspectiva de la gerencia hospitalaria. Métodos: Se elaboró un modelo matemático de coste-eficacia basado en un árbol de decisiones. Como variable de eficacia se utilizó la supervivencia libre de progresión, obtenida de los ensayos clínicos fase III PARAMOUNT, AVAIL y SAIL. El estudio se efectuó desde la perspectiva de la gerencia hospitalaria considerando únicamente los costes directos de adquisición de los fármacos. Se realizó un análisis de sensibilidad determinístico para comprobar la robustez de los resultados. Resultados: La SLP obtenida en los ensayos clínicos de los tratamientos cis/pem, cis/gem/bev y carb/pac/bev fue de: 6,9, 6,7 y 6,2 meses, respectivamente. En base a nuestro modelo, el coste medio del tratamiento por paciente para estos esquemas fue de 19.942 Euros, 15.594 Euros y 36.095 Euros, respectivamente. La razón coste-eficacia incremenal por mes de SLP adicional entre cis/pem y cis/gem/bev fue de 19.303 Euros. Estimando una reducción del 30% de los costes de adquisición de pemetrexed (Alimta®Eli Lilly Nederland B.V) ante su próxima incorporación al mercado de medicamentos genéricos, el tratamiento cis/pem se convertiría en la alternativa dominante en el tratamiento de primera línea de los pacientes con NSCLC, al ofrecer los mejores resultados en salud a un menor coste (AU)

Co-delivery of pemetrexed and miR-21 antisense oligonucleotide by lipid-polymer hybrid nanoparticles and effects on glioblastoma cells.

Combination therapy using anticancer drugs and nucleic acid is a more promising strategy to overcome multidrug resistance in cancer and to enhance apoptosis. In this study, lipid-polymer hybrid nanoparticles (LPNs), which contain both pemetrexed and miR-21 antisense oligonucleotide (anti-miR-21), have been developed for treatment of glioblastoma, the most aggressive type of brain tumor. Prepared LPNs have been well characterized by particle size distribution and zeta potential measurements, determination of encapsulation efficiency, and in vitro release experiments. Morphology of LPNs was determined by transmission electron microscopy. LPNs had a hydrodynamic size below 100 nm and exhibited sustained release of pemetrexed up to 10 h. Encapsulation of pemetrexed in LPNs increased cellular uptake from 6% to 78%. Results of confocal microscopy analysis have shown that co-delivery of anti-miR-21 significantly improved accumulation of LPNs in the nucleus of U87MG cells. Nevertheless, more effective cytotoxicity results could not be obtained due to low concentration of anti-miR-21, loaded in LPNs. We expect that the effective drug delivery systems can be obtained with higher concentration of anti-miR-21 for the treatment of glioblastoma.