N-trimethyl chitosan coated nano-complexes enhance the oral bioavailability and chemotherapeutic effects of gemcitabine.

N-trimethyl chitosan (TMC) is a multifunctional polymer that can be used in various nanoparticle forms in the pharmaceutical, nutraceutical and biomedical fields. In this study, TMC was used as a mucoadhesive adjuvant to enhance the oral bioavailability and hence antitumour effects of gemcitabine formulated into nanocomplexes composed of poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) conjugated with d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS). A central composite design was applied to achieve the optimal formulation. Cellular uptake and drug transportation studies revealed the nanocomplexes permeate over the intestinal cells via adsorptive-mediated and caveolae-mediated endocytosis. Pharmacokinetic studies demonstrated the oral drug bioavailability of the nanocomplexes was increased 5.1-fold compared with drug solution. In pharmacodynamic studies, the formulation reduced tumour size 3.1-fold compared with the drug solution. The data demonstrates that TMC modified nanocomplexes can enhance gemcitabine oral bioavailability and promote the anticancer efficacy.

Development of Gemcitabine Loaded PLGA/Lecithin Nanoparticles for Non-Small Cell Lung Cancer Therapy.

BACKGROUND: Compared to polymeric nanoparticles prepared using non-lipid surfactants, lecithin addition forms larger nanoparticles and exhibits higher drug loading and the stability of nanoparticles can be conferred by adding Vitamin E Polyethylene Glycol Succinate (TPGS) into the formulation. AIM: The aim of this study is to prepare Gemcitabine (Gem) loaded lecithin/PLGA nanoparticles. Moreover, the effect of TPGS and sodium cholate (SK) on the preparation of lecithin/PLGA nanoparticles was compared. METHODS: It was found that while PC addition into PLGATPGS nanoparticles formed larger particles (251.3± 6.0 nm for Gem-PLGATPGS NPs and 516,9 ± 3.9 nm for Gem-PLGA-PCTPGS NPs), the particle size of PLGASK nanoparticles was not affected by lecithin addition (p>0.05;). RESULTS: In cytotoxicity studies, it was found that the SK-MES-1 cell inhibition rates of Gem-PLGATPGS NPs, Gem-PLGA-PCTPGS NPs, Gem-PLGASK NPs, Gem-PLGA-PCSK NPs were similar with free Gem (p>0.05;). In cytotoxicity studies, it was found that the encapsulation into nanoparticles did not change the cytotoxicity of the drug. However, higher cellular uptake has been observed when the lecithin was used in the preparation of PLGA nanoparticles. CONCLUSION: Compared with free Gem, the Gem-loaded nanoparticles enhanced the uptake of the drug by SK-MES-1 cells which can increase the effect of gemcitabine for non-small cell lung cancer therapy.

Coix Seed Extract Enhances the Anti-Pancreatic Cancer Efficacy of Gemcitabine through Regulating ABCB1- and ABCG2-Mediated Drug Efflux: A Bioluminescent Pharmacokinetic and Pharmacodynamic Study.

A deep insight into the function and kinetics of ATP-binding cassette (ABC) transporters may aid in the development of pharmaceutics that can minimize the particular facet of chemo-resistance. We utilized bioluminescence imaging to monitor the ABC transporter mediated intracellular drug efflux function. We also investigated the potential association between the intracellular bioluminescent pharmacokinetic profiles and the anti-tumor efficacy of the coix seed extract and gemcitabine against pancreatic cancer cells in vitro and in vivo. The bioluminescent pharmacokinetic parameters and pharmacodynamic index (IC50 and TGI) were determined. The expression levels ABCB1 and ABCG2 were assessed. Results showed that coix seed extract could synergistically enhance the anti-cancer efficacy of gemcitabine (p < 0.05). Meanwhile coix seed extract alone or in combination with gemcitabine could significantly increase the AUCluc while decreasing the Kluc (p < 0.01). Western blot and immunohistochemistry assay demonstrated that coix seed extract could significantly mitigate gemcitabine-induced upregulation of ABCB1 and ABCG2 protein. The Pearson correlation analysis demonstrated that the bioluminescent pharmacokinetic parameters and pharmacodynamic index have strong association in vitro and in vivo. In conclusion coix seed extract could augment the efficacy of gemcitabine therapy in pancreatic cancer cells may at least partly due to the alteration of ABC transporter-mediated drug efflux function.

Black phosphorus nanosheets and gemcitabine encapsulated thermo-sensitive hydrogel for synergistic photothermal-chemotherapy.

The purpose of this study was to propose a thermosensitive hydrogel incorporating black phosphorus (BP) nanosheets and gemcitabine for chemo-photothermal combination therapy against cancer. The BP nanosheets were prepared by liquid exfoliation method and the thermo-sensitive hydrogel was prepared by "cold method" with Pluronic F127 as hydrogel matrix for intratumoral injection. BP nanosheets and the hydrogel were characterized by particle size, morphology, phase transition feature, near infrared photothermal conversion performance, photothermal stability and biodegradation. The in vitro release behaviors of gemcitabine were assessed. Moreover, the photothermal efficacy, and photothermal-chemotherapy combination were evaluated in mice bearing tumors. The BP nanosheets displayed uniform 2D sheet-like morphology with a diameter of about 200 nm. The hydrogel showed phase translation at near body temperature, great photothermal efficacy in vitro and good biodegradability. The hydrogel exhibited good photothermal effect in BALB/c mice bearing 4T1 xenograft tumors. The combination of photothermal therapy and chemotherapy displayed superior antitumor effect compared to chemotherapy alone.

FF-10832 enables long survival via effective gemcitabine accumulation in a lethal murine peritoneal dissemination model.

Chemotherapy has been the treatment of choice for unresectable peritoneal dissemination; however, it is difficult to eradicate such tumors because of poor drug delivery. To solve this issue, we developed FF-10832 as liposome-encapsulated gemcitabine to maintain a high concentration of gemcitabine in peritoneal tumors from the circulation and ascites. A syngeneic mouse model of peritoneal dissemination using murine Colon26 cell line was selected to compare the drug efficacy and pharmacokinetics of FF-10832 with those of gemcitabine. Despite the single intravenous administration, FF-10832 treatment enabled long-term survival of the lethal model mice as compared with those treated with gemcitabine. Pharmacokinetic analysis clarified that FF-10832 could achieve a more effective gemcitabine delivery to peritoneal tumors owing to better stability in the circulation and ascites. The novel liposome-encapsulated gemcitabine FF-10832 may be a curative therapeutic tool for cancer patients with unresectable peritoneal dissemination via the effective delivery of gemcitabine to target tumors.

Tumor-specific delivery of gemcitabine with activatable liposomes.

Gemcitabine delivery to pancreatic ductal adenocarcinoma is limited by poor pharmacokinetics, dense fibrosis and hypo-vascularization. Activatable liposomes, with drug release resulting from local heating, enhance serum stability and circulation, and the released drug retains the ability to diffuse within the tumor. A limitation of liposomal gemcitabine has been the low loading efficiency. To address this limitation, we used the superior solubilizing potential of copper (II) gluconate to form a complex with gemcitabine at copper:gemcitabine (1:4). Thermosensitive liposomes composed of DPPC:DSPC:DSPE-PEG2k (80:15:5, mole%) then reached 12 wt% loading, 4-fold greater than previously reported values. Cryo transmission electron microscopy confirmed the presence of a liquid crystalline gemcitabine­copper mixture. The optimized gemcitabine liposomes released 60% and 80% of the gemcitabine within 1 and 5 min, respectively, at 42 °C. Liposomal encapsulation resulted in a circulation half-life of ~2 h in vivo (compared to reported circulation of 16 min for free gemcitabine in mice), and free drug was not detected within the plasma. The resulting gemcitabine liposomes were efficacious against both murine breast cancer and pancreatic cancer in vitro. Three repeated treatments of activatable gemcitabine liposomes plus ultrasound hyperthermia regressed or eliminated tumors in the neu deletion model of murine breast cancer with limited toxicity, enhancing survival when compared to treatment with gemcitabine alone. With 5% of the free gemcitabine dose (5 rather than 100 mg/kg), tumor growth was suppressed to the same degree as gemcitabine. Additionally, in a more aggressive tumor model of murine pancreatic cancer, liposomal gemcitabine combined with local hyperthermia induced cell death and regions of apoptosis and necrosis.

A case report of a severe fluoropyrimidine-related toxicity due to an uncommon DPYD variant.

INTRODUCTION: Fluoropyrimidines such as 5-fluorouracil (5-FU) and its orally active prodrug, capecitabine, are widely used in the treatment of gastrointestinal cancer, including colorectal cancer. Dihydropyrimidine dehydrogenase (DPD) plays an important role in the 5-FU metabolism. Dihydropyrimidine dehydrogenase gene (DPYD) is a highly polymorphic gene with several hundreds of reported genetic variants and DPD activity levels vary considerably among individuals, with different 5-FU-related efficacy and toxicity. About 5% of the population is deficient in DPD enzyme activity. The most well studied DPYD variant is the IVS14+1G>A, also known as DPYD *2A. In this report, we present a case of a patient with a double heterozygote DPYD variant (DPYD activity score: 0,5 according to Clinical Pharmacogenetics Implementation Consortium) who experienced a severe fluoropyrimidine-related toxicity resolved without any consequence. PATIENT CONCERNS: A 46-years-old Caucasian man with diagnosis of left colon adenocarcinoma underwent left hemicolectomy on July 2017: pT3 G3 N1c M0. According to the disease stage, he started an adjuvant therapy with XELOX using capecitabine at 50% of total dose, because of his DPYD IVS14+1G>A variant, detected before the treatment. DIAGNOSIS: After few days, despite of this dose reduction, he experienced life-threatening adverse events such as mucositis G3, diarrhea G3, neutropenia G4, thrombocytopenia G4, and hyperbilirubinemia G3 according to Common Terminology Criteria for Adverse Events v 5.0. INTERVENTIONS: As first, we set up an intensive rehydration therapy, antibiotic and antifungal prophylaxis, Granulocyte-Colony Stimulating Factors, and supportive blood transfusions. Additional genetic tests revealed a double heterozygote variant of DPYD gene (DPYD IVS14+1G>A and 2846A>T) which is a very rare situation and only 3 cases are described in literature, all of them concluded with patient's death. OUTCOMES: After 3 weeks of intensive therapy, the patient was fully recovered. Furthermore, all the whole-body CT scans performed since discharge from the hospital until now, have confirmed no evidence of disease. CONCLUSIONS: Recent studies demonstrated that screening strategy for the most common DPYD variants allowed for avoiding toxicities and saving money. This report underlines the importance of genotyping DPYD before treatment and emphasizes the role of genotype-guided dose individualization.

Rabeprazole intake does not affect systemic exposure to capecitabine and its metabolites, 5'-deoxy-5-fluorocytidine, 5'-deoxy-5-fluorouridine, and 5-fluorouracil.

PURPOSE: Several retrospective studies have shown that the antitumor efficacy of capecitabine-containing chemotherapy decreases when co-administered with a proton pump inhibitor (PPI). Although a reduction in capecitabine absorption by PPIs was proposed as the underlying mechanism, the effects of PPIs on capecitabine pharmacokinetics remain unclear. We prospectively examined the effects of rabeprazole on the pharmacokinetics of capecitabine and its metabolites. METHODS: We enrolled patients administered adjuvant capecitabine plus oxaliplatin (CapeOX) for postoperative colorectal cancer (CRC) patients and metastatic CRC patients receiving CapeOX with/without bevacizumab. Patients receiving a PPI before registration were allocated to the rabeprazole group, and the PPI was changed to rabeprazole (20 mg/day) at least 1 week before the initiation of capecitabine treatment. On day 1, oral capecitabine (1000 mg/m2) was administered 1 h after rabeprazole intake. Oxaliplatin (and bevacizumab) administration on day 1 was shifted to day 2 for pharmacokinetic analysis of the first capecitabine dose. Plasma concentrations of capecitabine, 5'-deoxy-5-fluorocytidine, 5'-deoxy-5-fluorouridine, and 5-fluorouracil were analyzed by high-performance liquid chromatography. Effects of rabeprazole on inhibition of cell proliferation by each capecitabine metabolite were examined with colon cancer cells (COLO205 and HCT116). RESULTS: Five and 9 patients enrolled between September 2017 and July 2018 were allocated to rabeprazole and control groups, respectively. No significant effects of rabeprazole on area under the plasma concentration-time curve divided by capecitabine dose for capecitabine and its three metabolites were observed. Rabeprazole did not affect the proliferation inhibition of colon cancer cells by the respective capecitabine metabolites. CONCLUSION: Rabeprazole does not affect capecitabine pharmacokinetics.

Randomized phase 2 study of gemcitabine and cisplatin with or without vitamin supplementation in patients with advanced esophagogastric cancer.

PURPOSE: Preclinical research and prior clinical observations demonstrated reduced toxicity and suggested enhanced efficacy of cisplatin due to folic acid and vitamin B12 suppletion. In this randomized phase 2 trial, we evaluated the addition of folic acid and vitamin B12 to first-line palliative cisplatin and gemcitabine in patients with advanced esophagogastric cancer (AEGC). METHODS: Patients with AEGC were randomized to gemcitabine 1250 mg/m2 (i.v. days 1, 8) and cisplatin 80 mg/m2 (i.v. day 1) q 3 weeks with or without folic acid (450 µg/day p.o.) and vitamin B12 (1000 µg i.m. q 9 weeks). The primary endpoint was response rate (RR). Secondary endpoints included overall survival (OS), time to progression (TTP), toxicity, and exploratory biomarker analyses. Cisplatin sensitivity and intracellular platinum levels were determined in adenocarcinoma cell lines cultured under high and low folate conditions in vitro. RESULTS: Adenocarcinoma cells cultured in medium with high folate levels were more sensitive to cisplatin and this was associated with increased intracellular platinum levels. In the randomized phase 2 clinical trial, which ran from October 2004 to September 2013, treatment was initiated in 78 of 82 randomized pts, 39 in each study arm. The RR was similar; 42.1% for supplemented patients vs. 32.4% for unsupplemented patients; p = 0.4. Median OS and TTP were 10.0 and 5.9 months for supplemented vs. 7.7 and 5.4 months for unsupplemented patients (OS, p = 0.9; TTP, p = 0.9). Plasma homocysteine was lower in the supplemented group [n = 20, 6.9 ± 1.6 (mean ± standard error of mean, SEM) µM; vs. 12.5 ± 4.0 µM; p < 0.001]. There was no significant difference in the Cmax of gemcitabine and cisplatin in the two treatment groups. CONCLUSION: Folic acid and vitamin B12 supplementation do not improve the RR, PFS, or OS of cisplatin and gemcitabine in patients with AEGC.

Alterations in Pharmacokinetics of Gemcitabine and Erlotinib by Concurrent Administration of Hyangsayukgunja-Tang, a Gastroprotective Herbal Medicine.

Gemcitabine and erlotinib are the chemotherapeutic agents used in the treatment of various cancers and their combination is being accepted as a first-line treatment of advanced pancreatic cancer. Hyangsayukgunja-tang (HYT) is a traditional oriental medicine used in various digestive disorders and potentially helpful to treat gastrointestinal adverse effects related to chemotherapy. The present study was aimed to evaluate the effect of HYT on the pharmacokinetics of gemcitabine and erlotinib given simultaneously in rats. Rats were pretreated with HYT at an oral dose of 1200 mg/kg/day once daily for a single day or 14 consecutive days. Immediately after pretreatment with HYT, gemcitabine and erlotinib were administered by intravenous injection (10 mg/kg) and oral administration (20 mg/kg), respectively. The effects of HYT on pharmacokinetics of the two drugs were estimated by non-compartmental analysis and pharmacokinetic modeling. The pharmacokinetics of gemcitabine and erlotinib were not altered by single dose HYT pretreatment. However, the plasma levels of OSI-420 and OSI-413, active metabolites of erlotinib, were significantly decreased in the multiple dose HYT pretreatment group. The pharmacokinetic model estimated increased systemic clearances of OSI-420 and OSI-413 by multiple doses of HYT. These data suggest that HYT may affect the elimination of OSI-420 and OSI-413.

Phase I/II Study of Refametinib (BAY 86-9766) in Combination with Gemcitabine in Advanced Pancreatic cancer.

BACKGROUND: Activating KRAS mutations are reported in up to 90% of pancreatic cancers. Refametinib potently inhibits MEK1/2, part of the MAPK signaling pathway. This phase I/II study evaluated the safety and efficacy of refametinib plus gemcitabine in patients with advanced pancreatic cancer. METHODS: Phase I comprised dose escalation, followed by phase II expansion. Refametinib and gemcitabine plasma levels were analyzed for pharmacokinetics. KRAS mutational status was determined from circulating tumor DNA. RESULTS: Ninety patients overall received treatment. The maximum tolerated dose was refametinib 50 mg twice daily plus standard gemcitabine (1000 mg/m2 weekly). The combination was well tolerated, with no pharmacokinetic interaction. Treatment-emergent toxicities included thrombocytopenia, fatigue, anemia, and edema. The objective response rate was 23% and the disease control rate was 73%. Overall response rate, disease control rate, progression-free survival, and overall survival were higher in patients without detectable KRAS mutations (48% vs. 28%, 81% vs. 69%, 8.8 vs. 5.3 months, and 18.2 vs. 6.6 months, respectively). CONCLUSION: Refametinib plus gemcitabine was well tolerated, with a promising objective response rate, and had an acceptable safety profile and no pharmacokinetic interaction. There was a trend towards improved outcomes in patients without detectable KRAS mutations that deserves future investigation.

A liposomal formulation of the synthetic curcumin analog EF24 (Lipo-EF24) inhibits pancreatic cancer progression: towards future combination therapies.

BACKGROUND: Pancreatic cancer is one of the most lethal of human malignancies known to date and shows relative insensitivity towards most of the clinically available therapy regimens. 3,5-bis(2-fluorobenzylidene)-4-piperidone (EF24), a novel synthetic curcumin analog, has shown promising in vitro therapeutic efficacy in various human cancer cells, but insufficient water solubility and systemic bioavailability limit its clinical application. Here, we describe nano-encapsulation of EF24 into pegylated liposomes (Lipo-EF24) and evaluation of these particles in preclinical in vitro and in vivo model systems of pancreatic cancer. RESULTS: Transmission electron microscopy and size distribution studies by dynamic light scattering confirmed intact spherical morphology of the formed liposomes with an average diameter of less than 150 nm. In vitro, treatment with Lipo-EF24 induced growth inhibition and apoptosis in MIAPaCa and Pa03C pancreatic cancer cells as assessed by using cell viability and proliferation assays, replating and soft agar clonogenicity assays as well as western blot analyses. Lipo-EF24 potently suppressed NF-kappaB nuclear translocation by inhibiting phosphorylation and subsequent degradation of its inhibitor I-kappa-B-alpha. In vivo, synergistic tumor growth inhibition was observed in MIAPaCa xenografts when Lipo-EF24 was given in combination with the standard-of-care cytotoxic agent gemcitabine. In line with in vitro observations, western blot analysis revealed decreased phosphorylation of I-kappa-B-alpha in excised Lipo-EF24-treated xenograft tumor tissues. CONCLUSION: Due to its promising therapeutic efficacy and favorable toxicity profile Lipo-EF24 might be a promising starting point for development of future combinatorial therapeutic regimens against pancreatic cancer.

Preclinical studies of 5-fluoro-2'-deoxycytidine and tetrahydrouridine in pediatric brain tumors.

Chemotherapies active in preclinical studies frequently fail in the clinic due to lack of efficacy, which limits progress for rare cancers since only small numbers of patients are available for clinical trials. Thus, a preclinical drug development pipeline was developed to prioritize potentially active regimens for pediatric brain tumors spanning from in vitro drug screening, through intracranial and intra-tumoral pharmacokinetics to in vivo efficacy studies. Here, as an example of the pipeline, data are presented for the combination of 5-fluoro-2'-deoxycytidine and tetrahydrouridine in three pediatric brain tumor models. The in vitro activity of nine novel therapies was tested against tumor spheres derived from faithful mouse models of Group 3 medulloblastoma, ependymoma, and choroid plexus carcinoma. Agents with the greatest in vitro potency were then subjected to a comprehensive series of in vivo pharmacokinetic (PK) and pharmacodynamic (PD) studies culminating in preclinical efficacy trials in mice harboring brain tumors. The nucleoside analog 5-fluoro-2'-deoxycytidine (FdCyd) markedly reduced the proliferation in vitro of all three brain tumor cell types at nanomolar concentrations. Detailed intracranial PK studies confirmed that systemically administered FdCyd exceeded concentrations in brain tumors necessary to inhibit tumor cell proliferation, but no tumor displayed a significant in vivo therapeutic response. Despite promising in vitro activity and in vivo PK properties, FdCyd is unlikely to be an effective treatment of pediatric brain tumors, and therefore was deprioritized for the clinic. Our comprehensive and integrated preclinical drug development pipeline should reduce the attrition of drugs in clinical trials.

Oral and intravenous pharmacokinetics of 5-fluoro-2'-deoxycytidine and THU in cynomolgus monkeys and humans.

INTRODUCTION: 5-Fluoro-2'-deoxycytidine (FdCyd; NSC48006), a fluoropyrimidine nucleoside inhibitor of DNA methylation, is degraded by cytidine deaminase (CD). Pharmacokinetic evaluation was carried out in cynomolgus monkeys in support of an ongoing phase I study of the PO combination of FdCyd and the CD inhibitor tetrahydrouridine (THU; NSC112907). METHODS: Animals were dosed intravenously (IV) or per os (PO). Plasma samples were analyzed by LC-MS/MS for FdCyd, metabolites, and THU. Clinical chemistry and hematology were performed at various times after dosing. A pilot pharmacokinetic study was performed in humans to assess FdCyd bioavailability. RESULTS: After IV FdCyd and THU administration, FdCyd C(max) and AUC increased with dose. FdCyd half-life ranged between 22 and 56 min, and clearance was approximately 15 mL/min/kg. FdCyd PO bioavailability after THU ranged between 9 and 25 % and increased with increasing THU dose. PO bioavailability of THU was less than 5 %, but did result in plasma concentrations associated with inhibition of its target CD. Human pilot studies showed comparable bioavailability for FdCyd (10 %) and THU (4.1 %). CONCLUSION: Administration of THU with FdCyd increased the exposure to FdCyd and improved PO FdCyd bioavailability from <1 to 24 %. Concentrations of THU and FdCyd achieved after PO administration are associated with CD inhibition and hypomethylation, respectively. The schedule currently studied in phase I studies of PO FdCyd and THU is daily times three at the beginning of the first and second weeks of a 28-day cycle.

Waiting times for surgical and diagnostic procedures in public hospitals in Mexico / Tiempos de espera para procedimientos quirúrgicos y diagnósticos en hospitales públicos de México

Objective. A retrospective evaluation of waiting times for elective procedures was conducted in a sample of Mexican public hospitals from the following institutions: the Mexican Institute for Social Security (IMSS), the Institute for Social Security and Social Services for Civil Servants (ISSSTE) and the Ministry of Health (MoH). Our aim was to describe current waiting times and identify opportunities to redistribute service demand among public institutions. Materials and methods. We examined current waiting times and productivity for seven elective surgical and four diagnostic imaging procedures, selected on the basis of their relative frequency and comparability with other national health systems. Results. Mean waiting time for the seven surgical procedures in the three institutions was 14 weeks. IMSS and ISSSTE hospitals showed better performance (12 and 13 weeks) than the MoH hospitals (15 weeks). Mean waiting time for the four diagnostic procedures was 11 weeks. IMSS hospitals (10 weeks) showed better average waiting times than ISSSTE (12 weeks) and MoH hospitals (11 weeks). Conclusion. Substantial variations were revealed, not only among institutions but also within the same institution. These variations need to be addressed in order to improve patient satisfaction.

Objetivo. Se llevó a cabo una evaluación retrospectiva de los tiempos de espera para procedimientos electivos en una muestra de hospitales públicos en México de las siguientes instituciones: Instituto Mexicano del Seguro Social (IMSS), Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE) y Secretaría de Salud (SS). El propósito era describir la situación actual en materia de tiempos de espera e identificar oportunidades de redistribución de la demanda de servicios entre instituciones públicas. Material y métodos. Se analizaron los tiempos de espera y la productividad para siete procedimientos quirúrgicos y cuatro procedimientos diagnósticos seleccionados sobre la base de su frecuencia relativa y comparabilidad con otros sistemas de salud nacionales. Resultados. El tiempo de espera promedio para los siete procedimientos quirúrgicos en las tres instituciones fue de 14 semanas. Los hospitales del IMSS y el ISSSTE mostraron un mejor desempeño (12 y 13 semanas) frente a los hospitales de la SS (15 semanas). El tiempo de espera promedio para los cuatro procedimientos diagnósticos fue de 11 semanas. Los hospitales del IMSS mostraron un tiempo de espera promedio mejor (10 semanas) que los hospitales del ISSSTE (12 semanas) y la SS (11 semanas). Conclusión. Se identificaron variaciones importantes no sólo entre instituciones sino también al interior de cada una de ellas. Estas variaciones deben atenderse para así mejorar la satisfacción de los usuarios de los servicios.

Acute and delayed toxicity of gemcitabine administered during isolated lung perfusion: a preclinical dose-escalation study in pigs.

OBJECTIVES: Colorectal cancer is the third most commonly diagnosed cancer worldwide, with up to 25% of patients presenting with metastases at the time of diagnosis. Despite pulmonary metastasectomy many patients go on to develop pulmonary recurrence, which might be linked to the presence of lung micrometastases. In this setting, the adjuvant administration of high-dose chemotherapy by isolated lung perfusion (ILP) has shown encouraging results. However, the tolerance to and efficacy of modern gemcitabine (GEM)-based chemotherapy regimens during adjuvant ILP remain unknown. We conducted a dose-escalating preclinical study to evaluate the immediate and delayed toxicity of GEM in a pig model to define dose-limiting toxicity (DLT) and maximum tolerated concentration. METHODS: Twenty-three pigs were given increasing concentrations of GEM during ILP, and were awakened at the end of the procedure. The concentrations of GEM were 40, 80, 160, 320, 640 and 1280 µg/ml. Serum and lung samples were taken to measure GEM concentrations. Pulmonary damage was evaluated by histological examination and cleaved caspase-3 detection. Immediate and delayed (1 month) toxicity were recorded. RESULTS: All of the animals underwent successful ILP with GEM. No systemic leak was observed. The three pigs that received a concentration of GEM of 1280 µg/ml died of hypoxia after lung recirculation at the end of the procedure. Eleven pigs survived for 1 month. Major lung toxicity was observed for the concentration of GEM of 640 µg/ml, both at the end of the procedure and after 1 month. DLT was defined at the concentration of 640 µg/ml and the maximum tolerated dose (MTD) was defined at the concentration of 320 µg/ml. CONCLUSIONS: ILP with GEM is a safe and reproducible technique in this large-animal model, which includes 1 month of survival. The MTD in this pig model was a concentration of GEM of 320 µg/ml.

Formulation and evaluation of gemcitabine-loaded solid lipid nanoparticles.

Gemcitabine-loaded solid lipid nanoparticles (SLNs) were produced by double emulsification technique using stearic acid as lipid, soy lecithin as surfactant and sodium taurocholate as cosurfactant. Prepared nanoparticles are characterized for particle size and surface morphology using scanning electron microscopy (SEM). Particle yield, entrapment efficiency and zeta potential were also determined. In-vitro release studies were performed in phosphate-buffered saline (PBS) pH 7.4 using metabolic shaker. The formulation F6 with maximum entrapment efficiency 72.42% and satisfactory in-vitro release was selected. In-vivo tissue distribution to liver, spleen, lung, heart and kidneys of optimized formulation followed by stability study under specific conditions were also determined. This investigation has shown preferential drug targeting to liver followed by spleen, lungs, kidneys and heart. Stability studies showed no significant change in the particle size followed with very slight decrease in entrapment efficiency at 25 ± 2 °C/60 ± 5% RH over a period of three months.

[Pharmacogenomics of the first-line treatment for gastric cancer: advances in the identification of genomic biomarkers for clinical response to chemotherapy]. / Farmacogenómica del tratamiento de primera linea en el cáncer gástrico: avances en la identificación de los biomarcadores genómicos de respuesta clínica.

Gastric cancer (GC) is often diagnosed at later stages due to the lack of specificity of symptoms associated with the neoplasm, causing high mortality rates worldwide. The first line of adjuvant and neoadjuvant treatment includes cytotoxic fluoropyrimidines and platin-containing compounds which cause the formation of DNA adducts. The clinical outcome with these antineoplastic agents depends mainly on tumor sensitivity, which is conditioned by the expression level of the drug targets and the DNA-repair system enzymes. In addition, some germ line polymorphisms, in genes linked to drug metabolism and response to chemotherapy, have been associated with poor responses and the development of adverse effects, even with fatal outcomes in GC patients. The identification of genomic biomarkers, such as individual gene polymorphisms or differential expression patterns of specific genes, in a patient-by-patient context with potential clinical application is the main focus of current pharmacogenomic research, which aims at developing a rational and personalized therapy (i.e., a therapy that ensures maximum efficacy with no predictable side effects). However, because of the future application of genomic technologies in the clinical setting, it is necessary to establish the prognostic value of these genomic biomarkers with genotype-phenotype association studies and to evaluate their prevalence in the population under treatment. These issues are important for their cost-effectiveness evaluation, which determines the feasibility of using these medical genomic research products for GC treatment in the clinical setting.

Farmacogenómica del tratamiento de primera línea en el cáncer gástrico: avances en la identificación de los biomarcadores genómicos de respuesta clínica / Pharmacogenomics of the first-line treatment for gastric cancer: advances in the identification of genomic biomarkers for clinical response to chemotherapy

Debido a la inespecificidad de los síntomas, el cáncer gástrico (CG) es diagnosticado frecuentemente en etapas avanzadas, lo que da cuenta de los altos índices de mortalidad debido a esta neoplasia a nivel mundial. El esquema de tratamiento adyuvante o neoadyuvante en los países occidentales incluye el uso de fluoropirimidinas citotóxicas y compuestos de platino formadores de aductos en el ADN. La respuesta clínica al tratamiento con estos fármacos depende principalmente de la sensibilidad del tumor, la cual a su vez está condicionada por el nivel de expresión de los blancos terapéuticos y de las enzimas de reparación del ADN. Sumado a esto, algunos polimorfismos de línea germinal en genes asociados al metabolismo y a la respuesta a estos fármacos, han mostrado asociación con respuestas pobres y con el desarrollo de eventos adversos, incluso con resultados fatales. La identificación de biomarcadores genómicos, en la forma de polimorfismos genéticos o la expresión diferencial de genes específicos asociados a la respuesta quimioterapeútica ha sido motivo de intensa investigación como base para la aplicación de la farmacogenómica en el establecimiento de una terapia farmacológica racional y personalizada del CG. Sin embargo, ante la eventual aplicación de la farmacogenómica en el ámbito clínico, es necesario establecer el valor pronóstico real de dichos biomarcadores mediante los estudios de asociación genotipo-fenotipo, así como su prevalencia en el contexto de cada población de pacientes. Estos aspectos son indispensables al evaluar la relación costo-efectividad de la introducción de los productos de la medicina genómica predictiva en el tratamiento del CG.

Gastric cancer (GC) is often diagnosed at later stages due to the lack of specificity of symptoms associated with the neoplasm, causing high mortality rates worldwide. The first line of adjuvant and neoadjuvant treatment includes cytotoxic fluoropyrimidines and platin-containing compounds which cause the formation of DNA adducts. The clinical outcome with these antineoplastic agents depends mainly on tumor sensitivity, which is conditioned by the expression level of the drug targets and the DNA-repair system enzymes. In addition, some germ line polymorphisms, in genes linked to drug metabolism and response to chemotherapy, have been associated with poor responses and the development of adverse effects, even with fatal outcomes in GC patients. The identification of genomic biomarkers, such as individual gene polymorphisms or differential expression patterns of specific genes, in a patient-by-patient context with potential clinical application is the main focus of current pharmacogenomic research, which aims at developing a rational and personalized therapy (i.e., a therapy that ensures maximum efficacy with no predictable side effects). However, because of the future application of genomic technologies in the clinical setting, it is necessary to establish the prognostic value of these genomic biomarkers with genotype-phenotype association studies and to evaluate their prevalence in the population under treatment. These issues are important for their cost-effectiveness evaluation, which determines the feasibility of using these medical genomic research products for GC treatment in the clinical setting.

Phase 1 pharmacogenetic and pharmacodynamic study of sorafenib with concurrent radiation therapy and gemcitabine in locally advanced unresectable pancreatic cancer.

PURPOSE: To define the safety, efficacy, and pharmacogenetic and pharmacodynamic effects of sorafenib with gemcitabine-based chemoradiotherapy (CRT) in locally advanced pancreatic cancer. METHODS AND MATERIALS: Patients received gemcitabine 1000 mg/m(2) intravenously weekly × 3 every 4 weeks per cycle for 1 cycle before CRT and continued for up to 4 cycles after CRT. Weekly gemcitabine 600 mg/m(2) intravenously was given during concurrent intensity modulated radiation therapy of 50 Gy to gross tumor volume in 25 fractions. Sorafenib was dosed orally 400 mg twice daily until progression, except during CRT when it was escalated from 200 mg to 400 mg daily, and 400 mg twice daily. The maximum tolerated dose cohort was expanded to 15 patients. Correlative studies included dynamic contrast-enhanced MRI and angiogenesis genes polymorphisms (VEGF-A and VEGF-R2 single nucleotide polymorphisms). RESULTS: Twenty-seven patients were enrolled. No dose-limiting toxicity occurred during induction gemcitabine/sorafenib followed by concurrent CRT. The most common grade 3/4 toxicities were fatigue, hematologic, and gastrointestinal. The maximum tolerated dose was sorafenib 400 mg twice daily. The median progression-free survival and overall survival for 25 evaluable patients were 10.6 and 12.6 months, respectively. The median overall survival for patients with VEGF-A -2578 AA, -1498 CC, and -1154 AA versus alternate genotypes was 21.6 versus 14.7 months. Dynamic contrast-enhanced MRI demonstrated higher baseline K(trans) in responding patients. CONCLUSIONS: Concurrent sorafenib with CRT had modest clinical activity with increased gastrointestinal toxicity in localized unresectable pancreatic cancer. Select VEGF-A/VEGF-R2 genotypes were associated with favorable survival.