Vaccine development and technology for SARS-CoV-2: Current insight.

Severe acute respiratory syndrome coronavirus 2 is associated with a severe respiratory disease in China, that rapidly spread across continents. Since the beginning of the pandemic, available data suggested the asymptomatic transmission and patients were treated with specific drugs with efficacy and safety data not always satisfactory. The aim of this review is to describe the vaccines developed by three companies, Pfizer-BioNTech, Moderna, and University of Oxford/AstraZeneca, in terms of both technological and pharmaceutical formulation, safety, efficacy, and immunogenicity. A critical analysis of Phases 1, 2, and 3 clinical trial results available was conducted, comparing the three vaccine candidates, underlining their similarities and differences. All candidates showed consistent efficacy and tolerability; although some differences can be noted, such as their technological formulation, temperature storage, which will be related to logistics and costs. Further studies will be necessary to evaluate long-term effects and to assess the vaccine safety and efficacy in the general population.

A unique squalenoylated and nonpegylated doxorubicin nanomedicine with systemic long-circulating properties and anticancer activity.

We identified that the chemical linkage of the anticancer drug doxorubicin onto squalene, a natural lipid precursor of the cholesterol's biosynthesis, led to the formation of squalenoyl doxorubicin (SQ-Dox) nanoassemblies of 130-nm mean diameter, with an original "loop-train" structure. This unique nanomedicine demonstrates: (i) high drug payload, (ii) decreased toxicity of the coupled anticancer compound, (iii) improved therapeutic response, (iv) use of biocompatible transporter material, and (v) ease of preparation, all criteria that are not combined in the currently available nanodrugs. Cell culture viability tests and apoptosis assays showed that SQ-Dox nanoassemblies displayed comparable antiproliferative and cytotoxic effects than the native doxorubicin because of the high activity of apoptotic mediators, such as caspase-3 and poly(ADP-ribose) polymerase. In vivo experiments have shown that the SQ-Dox nanomedicine dramatically improved the anticancer efficacy, compared with free doxorubicin. Particularly, the M109 lung tumors that did not respond to doxorubicin treatment were found inhibited by 90% when treated with SQ-Dox nanoassemblies. SQ-Dox nanoassembly-treated MiaPaCa-2 pancreatic tumor xenografts in mice decreased by 95% compared with the tumors in the saline-treated mice, which was significantly higher than the 29% reduction achieved by native doxorubicin. Concerning toxicity, SQ-Dox nanoassemblies showed a fivefold higher maximum-tolerated dose than the free drug, and moreover, the cardiotoxicity study has evidenced that SQ-Dox nanoassemblies did not cause any myocardial lesions, such as those induced by the free doxorubicin treatment. Taken together, these findings demonstrate that SQ-Dox nanoassemblies make tumor cells more sensitive to doxorubicin and reduce the cardiac toxicity, thus providing a remarkable improvement in the drug's therapeutic index.

A randomized double-blind placebo controlled phase I-II study on clinical and molecular effects of dietary supplements in men with precancerous prostatic lesions. Chemoprevention or "chemopromotion"?

BACKGROUND: Antioxidants effectiveness in prostate cancer (PCa) chemoprevention has been severely questioned, especially after the recent results of the Selenium and Vitamin E Cancer Prevention Trial. We present the results of a double-blind randomized controlled trial (dbRCT) on the pharmacokinetic, clinical, and molecular activity of dietary supplements containing lycopene, selenium, and green tea catechins (GTCs) in men with multifocal high grade prostatic intraepithelial neoplasia (mHGPIN) and/or atypical small acinar proliferation (ASAP). METHODS: From 2009 to 2014, we conducted a dbRCT including 60 patients with primary mHGPIN and/or ASAP receiving daily lycopene 35 mg, selenium 55 µg, and GTCs 600 mg, or placebo for 6 months. Pharmacokinetic analysis were performed with UV-Visible spectrophotometric assay under standard (SC) and accelerated (AC) conditions. Upon plasma lycopene concentrations falling within the expected range (1.2-90 mcg/l) and no side-effects of grade >1, study proceeded to phase II (n = 50). After unblinding of results, eight men (4 per arm, 2 without and 2 with PCa, respectively) were randomly selected and totRNA extracted from "non-pathological" tissues. MicroRNA profiling was performed with the Agilent platform. Raw data processing used R-statistical language and linear models for microarray analysis. RESULTS: Samples were stable except for lycopene, showing significant degradation (SC = 56%, AC = 59%) and consequently stabilized under vacuum in a dark packaging. Mean plasmatic lycopene concentration was 1,45 ± 0,4 µM. At 6 months, 53 men underwent re-biopsy and 13 (24.5%) were diagnosed with PCa (supplementation n = 10, placebo n = 3 [P = 0.053]). At a mean 37 months follow-up, 3 additional PCa were found in the placebo group. No significant variations in PSA, IPSS, and PR25 questionnaires were observed. Stronger modulation of miRNAs was present on re-biopsy in the supplementation group compared to the placebo, including: (i) overexpression of miRNAs present in PCa versus non-cancer tissue; (ii) underexpression of miRNAs suppressing PCa proliferation; (iii) detection of 35 miRNAs in PCa patients versus disease-free men, including androgen-regulated miR-125b-5p and PTEN-targeting miR-92a-3p (both upregulated). CONCLUSION: Administration of high doses of lycopene, GTCs, and selenium in men harboring HGPIN and/or ASAP was associated with a higher incidence of PCa at re-biopsy and expression of microRNAs implicated in PCa progression at molecular analysis. The use of these supplements should be avoided.

Novel nanoassemblies composed of squalenoyl-paclitaxel derivatives: synthesis, characterization, and biological evaluation.

Using the anticancer compound paclitaxel as a model drug, this study investigates the potential of the squalenoylation technology (i.e., bioconjugation with the natural lipid squalene) in addressing the drug ability and delivery issues of poorly soluble therapeutic agents. In this view, a variety of novel squalene-based prodrugs of the anticancer compound paclitaxel were synthesized, which produced nanoparticles in water. These prodrugs were obtained by covalent coupling of the paclitaxel 2'-hydroxyl group as direct ester, as well as with a succinate or a diglycolate ester as cleavable linker to the 1,1',2-tris-norsqualenoic acid. The hydrophilicity of these paclitaxel bioconjugates was increased by placing poly(ethylene glycol) chains of different lengths between paclitaxel and the squalenoyl moiety. All these prodrugs self-assembled into nanosized aggregates in aqueous solution as characterized by dynamic light scattering, atomic force microscopy, and transmission electron microscopy. The critical aggregation concentration was very low, ranging from 0.09 to 0.4 mg/L. Zeta potential measurements revealed that all squalenoyl-paclitaxel nanoassemblies (NA) held a global negative charge and appeared stable in water for several weeks as determined by particle size measurement. The release of paclitaxel from NA was evaluated in different conditions and in the presence of serum and depended on the nature of the linker used. Preliminary biological assessment showed that these squalenoyl-paclitaxel NA induced the formation of microtubule bundles in HT-29 and KB-31 cells, and additionally displayed notable cytotoxicity on a lung tumor cell line. Furthermore, the cytotoxic activity of these different prodrugs correlated closely with the observed linker stability. Overall, the squalenoylation nanotechnology opens up interesting perspectives for the development of injectable prodrugs of poorly soluble therapeutic compounds by addressing the associated physicochemical and biopharmaceutical challenges.

Pharmacokinetic study to optimize the intravesical administration of gemcitabine.

OBJECTIVES: To assess in a phase II pharmacokinetic study whether different pH levels, dilution volumes and exposure times affect intracellular bioavailability and systemic absorption of gemcitabine. SUBJECTS AND METHODS: Six arms of three patients each with a non-muscle-invasive bladder cancer (NMIBC) were planned to receive six combinations of two different dilution volumes (50 mL vs 100 mL), two pH levels (2.5-3.5 vs 5.5) and two exposure times (1 h vs 2 h) of the study drug. Blood samples were taken before, during and 1 h after drug instillation. Cold biopsy specimens from the exophytic tumor, its base of implant and a macroscopically healthy mucosa were taken during transurethral resection. High-pressure liquid chromatography/high-resolution mass spectrometry (HPLC/HRMSn) analysis of plasma and tissue samples was used to determine concentrations of gemcitabine (dFdC) and its inactive metabolite (dFdU). RESULTS: The arm at pH 5.5 in 50 mL was withdrawn as 2000 mg dFdC are insoluble in these conditions. The different instillation conditions resulted in negligible plasma dFdC concentrations but significant differences in intracellular content and metabolism of dFdC. The lowest intratissue concentration of dFdC was detected in a 50 mL solution at a pH of 2.5-3.5 kept in the bladder for 1 h (standard arm). A pH 5.5 solution in 100 mL with a 2-h exposure favored the maximal intratumoral dFdC absorption which was 90 times higher than that recorded in the standard arm. CONCLUSIONS: The most commonly reported administration scheme of gemcitabine produced the lowest tissue bioavailability of dFdC. Other combinations of pH, dilution volume and duration of instillation proved more advantageous and merit testing in clinical trials.

Administration of reduced glutathione in FOLFOX4 adjuvant treatment for colorectal cancer: effect on oxaliplatin pharmacokinetics, Pt-DNA adduct formation, and neurotoxicity.

Oxaliplatin is a promising drug for cancer therapy and the oxaliplatin/5-fluorouracil/leucovorin (FOLFOX) regimen has become the standard adjuvant treatment for colorectal cancer. However, the oxaliplatin-induced neurotoxicity still represents a clinical problem leading to a discontinuation of the therapy. Many strategies have been proposed in order to manage the neurotoxicity, but their effect on antitumoral efficacy is still unclear. In this study, we investigated the effect of reduced glutathione administration on neurotoxicity, oxaliplatin pharmacokinetics, and platinum-DNA (Pt-DNA) adduct formation in patients affected by colorectal cancer treated with FOLFOX4 adjuvant regimen. Twenty-seven patients were randomized to receive GSH 1500 mg/m or saline solution before oxaliplatin infusion. Evaluation of neurotoxicity, pharmacokinetics of plasmatic total and ultrafiltered Pt, and determination of Pt-DNA adduct formation on white blood cells was performed during the 5th, 9th, and 12th cycles. At the end of all cycles of therapy, the patients in the GSH arm showed a statistically significant reduction of neurotoxicity (P=0.0037) compared with the placebo arm. There were no significant differences in the main pharmacokinetic parameters between the two arms except a lower area under the plasma concentration-time curve and a smaller apparent steady-state volume of distribution (Vss) when GSH was coadministered. This difference can be explained by the natural function of GSH in the detoxification of oxaliplatin and by its ability to remove the Pt bound to plasma proteins. The determination of Pt-DNA adduct formation shows no statistically significant differences between the two arms. In conclusion, this study indicates that coadministration of GSH is an effective strategy to reduce the oxaliplatin-induced neurotoxicity without impairing neither the pharmacokinetics of oxaliplatin, nor the Pt-DNA adduct formation.

Paclitaxel and pegylated liposomal doxorubicin in recurrent head and neck cancer: clinical and unexpected pharmacokinetic interactions.

BACKGROUND: The combination of paclitaxel (PTX) with pegylated liposomal doxorubicin (PLD) is an interesting treatment for recurrent head and neck cancer. The pharmacokinetic behavior may depend on the interval between the intravenous administration of the two drugs. This study evaluates the clinical efficacy, toxicity and any possible interval-dependent pharmacokinetic interactions. PATIENTS AND METHODS: Thirty patients were randomized to receive 80 mg/m2 PTX weekly and 12.5 mg/m2 PLD every two weeks at administration intervals of 0, 1, 3, 12 or 24 hours. Blood sampling was performed at day 1 and 15 and pharmacokinetics of PTX, PLD and Cremophor EL were evaluated by non-compartmental analysis. RESULTS: Neutropenia was the most frequent side-effect (100% of patients; 30% grade 3-4). Hand-foot syndrome was severe in only 3% of patients. Overall response rate was 30%, with 3% complete responses and 27% partial responses. Stable disease and progression were 43% and 27%, respectively. Median response duration and overall median survival were 5.5 and 10 months respectively. Co-administration of PLD markedly reduced Cmax and the area under the curve (AUC), and increased PTX clearance. The differences in the PTX AUC and clearance between the 0 h and the 24 h experimental arms were statistically significant. CONCLUSION: The PTX/PLD combination plays a palliative role (clinical benefit in 73% of patients) and has good tolerability. The PTX pharmacokinetic profile was unexpectedly affected by different administration time intervals; in the 0 h arm the AUC was reduced to one fourth, therefore a schedule with PTX on day one, PLD on day two may be preferred.

Antitumor activity and pharmacokinetics of liposomes containing lipophilic gemcitabine prodrugs.

BACKGROUND: Gemcitabine is a deoxycytidine analogue that exhibits antitumoral activity against adenocarcinomas of the colon, lung and pancreas. After intravenous injection, gemcitabine is rapidly converted to the inactive metabolite 2'-deoxy-2',2'-difluorouridine by cytidine deaminase. MATERIALS AND METHODS: To improve the pharmacokinetic behavior and the antitumor activity of the drug, the gemcitabine prodrug, 4-(N)-stearoylgemcitabine (C18gem) was incorporated in liposomes and both the pharmacokinetic and the in vivo activity of this formulation intravenously or peritumorally administered in nude female CR1:Nu/Nu(CD-1)BR mice grafted with HT-29 and KB 396p cells were studied. RESULTS: The C18gem-liposomes showed both higher plasma half life and tumor regression than control and gemcitabine. CONCLUSION: The incorporation of C18gem-prodrug in liposomes increased the plasma half life of the drug resulting in increased accumulation in the tumor cells and a higher level of antitumoral efficacy. The results obtained with different tumors sensitive to gemcitabine support the efficacy of this proposed drug delivery system.

Biological characterization of folic acid-conjugated poly(H2NPEGCA-co-HDCA) nanoparticles in cellular models.

The folate receptor (FR) is a highly selective tumor marker over expressed in many human cancers and it constitutes a useful target for tumor-specific drug delivery. Thus, the conjugation of folic acid to different drugs or drug carriers may enhance the delivery of the therapeutic agent to FR-positive tumor cells. The aim of this study was to investigate the interactions of folate-conjugated polyalkylcyanoacrylate nanoparticles with tumor cells overexpressing the FR. For this purpose, nanoparticles were prepared by nanoprecipitation of the poly[aminopoly(ethylene glycol) cyanoacrylate-co-hexadecyl cyanoacrylate] [poly(H2NPEGCA-co-HDCA)] copolymer and labeled with the hydrophobic fluorescent dye nile red. Nile red-loaded nanoparticles were then conjugated to folic acid via the PEG terminal amino groups. Four human cancer cell lines were then tested by western blot in order to evaluate the FR expression levels. KB3-1 cell line showed the higher expression level, while MCF-7 cells were taken as a control. After measuring the cytotoxicity of the nanoparticles on these two cell lines, fluorescent folate-nanoparticles were incubated with them and the cellular uptake was evaluated by confocal microscopy and flow cytometry. KB3-1 cells showed a greater nanoparticle internalization, when compared to MCF-7 cells.

Encapsulation of gemcitabine lipophilic derivatives into polycyanoacrylate nanospheres and nanocapsules.

The aim of this study was to develop both a physical and a chemical protection of the anticancer drug gemcitabine, which suffers from a rapid plasmatic metabolization. For this purpose, we used a series of lipophilic derivatives of gemcitabine in which an acyl chain is covalently coupled to the 4-amino group of gemcitabine; moreover, a physical protection of the drug was attempted by incorporating these lipophilic derivatives into poly(H(2)NPEGCA-co-HDCA) nanospheres and nanocapsules. Nanoparticles were prepared by nanoprecipitation of the poly(H(2)NPEGCA-co-HDCA) copolymer and their size, zeta potential and encapsulation efficiency were further characterized. These results have been relied on lipophilicity and flexibility studies. Data showed that only the more lipophilic derivative, 4-(N)-stearoylgemcitabine, was incorporated with a high yield. Thus, 4-(N)-stearoylgemcitabine-containing nanospheres and nanocapsules were further analyzed by differential scanning calorimetry. Their cytotoxicity was tested on two human cancer cell lines and compared to that of gemcitabine and free 4-(N)-stearoylgemcitabine.

Interaction of lipophilic gemcitabine prodrugs with biomembrane models studied by Langmuir-Blodgett technique.

The stability and bioavailability of anticancer agents, such as gemcitabine, can be increased by forming prodrugs. Gemcitabine is rapidly deaminated to the inactive metabolite (2('),2(')-difluorodeoxyuridine), thus to improve its stability a series of increasingly lipophilic gemcitabine prodrugs linked through the 4-amino group to valeroyl, lauroyl, and stearoyl acyl chains were synthesized. Studies of monolayer properties are important to improve understanding of biological phenomena involving lipid/gemcitabine or lipid/gemcitabine derivative interactions. The interfacial behavior of monolayers constituted by DMPC plus gemcitabine or lipophilic gemcitabine prodrugs at increasing molar fractions was studied at the air/water interface at temperatures below (10 degrees C) and above (37 degrees C) the lipid phase transition. The effect of the hydrophobic chain length of gemcitabine derivatives on the isotherm of pure DMPC was investigated by surface tension measurement, and the results are reported as molar fractions as a function of mean molecular area per molecule. The results show that the compounds interact with DMPC producing mixed monolayers that are subject to an expansion effect, depending on the prodrug chain length. The results give useful hints of the interaction of these prodrugs with biological membranes and increase knowledge on the incorporation site of such compounds, as a function of their lipophilicity, in a lipid carrier; they may lead to improved liposomal formulation design.

Enhancement of gemcitabine affinity for biomembranes by conjugation with squalene: differential scanning calorimetry and Langmuir-Blodgett studies using biomembrane models.

Molecular interactions between gemcitabine, alone or conjugated with squalene to form the gem-squalene prodrug, with dimyristoylphosphatidylcholine have been investigated by differential scanning calorimetry and Langmuir film balance techniques to gain information about the interaction of gemcitabine and its prodrug with mammalian cell membranes and to evaluate the potential of liposomes as a delivery system for gemcitabine prodrugs. Phospholipids assembled as multilamellar vesicles or monolayers (at the air water interface) have been used as biomembrane models. Different interactions of gemcitabine, its prodrug, and squalene with the lipid were detected by dispersing the compounds in the MLV and were compared with kinetic experiments carried out to consider the ability of the examined compounds to dissolve in an aqueous medium, to migrate through it, and to be captured by multilamellar vesicles. Their ability to be released from drug-loaded liposomes and be taken up by empty vesicles mimicking biomembranes was also considered. Analysis of the differential scanning calorimetry curves reveals that gemcitabine has very little interaction with multilamellar vesicles whereas the gem-squalene prodrug strongly interacts with multilamellar vesicles. The kinetic experiments suggest that an aqueous medium does not permit the prodrug uptake by the biomembrane models, whereas it is allowed when gem-squalene is gradually released by the liposomes. The molecular area/surface pressure isotherms of the gemcitabine/lipid, gem-squalene/lipid, and pure compound monolayers, in agreement with the calorimetric results, indicate that gem-squalene interacts with the phospholipid monolayer with the squalene moiety in contact with the phospholipid chains and gemcitabine protruding in the aqueous medium.

Pegylated liposomal doxorubicin and vinorelbine in recurrent ovarian carcinoma: a pharmacokinetic study on alternate administration sequences.

BACKGROUND: This multicenter pharmacokinetic study evaluated the pharmacokinetics and toxicity of the combination of pegylated liposomal doxorubicin (PLD) and vinorelbine (VNR) in patients with recurrent ovarian cancer, when administered in opposing sequences. PATIENTS AND METHODS: Eighteen heavily pre-treated ovarian cancer patients received treatment with PLD 30 mg/m2 and VNR 30 mg/m2 every 3 weeks for 6 cycles, 9 being given the PLD-VNR sequence vs. 9 the VNR-PLD sequence. RESULTS: The VNR AUCtot and plasma levels were considerably higher with the PLD-VNR sequence and VNR clearance, clearly related to Kel, was about half that occurring with VNR-PLD. Toxicity was generally mild and reversible. In both arms, a sound correlation was found between VNR AUCtot and absolute neutrophil count decrease. A possible correlation between hematological toxicity and the 2 opposing administration sequences was also shown. CONCLUSION: The higher VNR AUCtot and plasma levels during the elimination phase with the PLD-VNR sequence may be related to a P-gp membrane glycoprotein inhibition by PLD vescicles which, in turn, may influence the plasma level of the associated VNR. PLD-VNR, producing a higher plasma level and very mild toxicity, may be considered the preferred sequence.

Preparation, characterization, cytotoxicity and pharmacokinetics of liposomes containing lipophilic gemcitabine prodrugs.

Gemcitabine is a known anticancer agent rapidly deaminated to the inactive metabolite 2',2'-difluorodeoxyuridine; it must therefore be administered at very high dose. Many different approaches have been tried to improve the metabolic stability; we synthesized a series of increasingly lipophilic prodrugs of gemcitabine by linking the 4-amino group with valeroyl, heptanoyl, lauroyl and stearoyl linear acyl derivatives. We studied their stability at storage, in plasma and with the lysosomal intracellular enzyme cathepsins. We studied incorporation of these lipophilic prodrugs in liposomes, where their encapsulation efficiency (EE) closely depends on the length of the saturated 4-(N)-acyl chain, the phospholipids chosen and the presence of cholesterol. A maximum EE of 98% was determined for 4-(N)-stearoyl-gemcitabine incorporated in DSPC/DSPG 9:1. This formulation was correlated with the highest stability in vitro and in vivo. Cytotoxicity of gemcitabine prodrugs, free or encapsulated in liposomes, was between two- and sevenfold that of free gemcitabine. Encapsulation of long-chain lipophilic prodrugs of gemcitabine in liposomes protected the drug from degradation in plasma, assuring a long plasma half-time and intracellular release of the free drug.

Preparation, characterization, cytotoxicity and pharmacokinetics of liposomes containing docetaxel.

The taxanes, paclitaxel and docetaxel, are anticancer agents used in clinical trials against ovarian carcinoma, breast, lung and head/neck cancer. Paclitaxel, very insoluble in water, is generally formulated using Cremophor EL. Docetaxel, more soluble in water, is formulated using Tween 80 and ethanol. Tween 80, albeit less toxic than Cremophor EL, may be responsible of some toxic effects. To eliminate these vehicles and improve the drug's antitumor efficacy, taxanes have been incorporated in liposomes. We compared formulation, stability, biodistribution and pharmacokinetics of docetaxel in conventional and PEGylated liposomes. Of the several formulations examined, docetaxel-liposomes composed of ePC/PG/CHOL 9:1:2 and ePC/PG/DSPE-PEG2000/CHOL 9:1:2:0.7 were the most effective. Both conventional and PEGylated docetaxel-liposomes were stable at 4 degrees C after 15 days, whereas in the presence of serum at 37 degrees C they were less stable. The IC50 values of docetaxel-liposomes, evaluated on HT-29 and Igrov1 cell lines, remained very high. Pharmacokinetics and biodistribution were evaluated in Balb/c mice after i.v. injection of [14C]docetaxel, formulated in Tween 80 or in 3H-labeled conventional or PEGylated liposomes. The t(1/2)beta, which was low for docetaxel (52.3 min), rose to 260 min for conventional docetaxel-liposomes and to 665 min for PEGylated docetaxel liposomes. Biodistribution studies confirmed the pharmacokinetics.

Pharmacokinetics of cisplatin in semi-closed hyperthermic peritoneal perfusion (HPP) for treatment of peritoneal carcinomatosis.

BACKGROUND: This study investigates the pharmacokinetics and toxicity of cisplatin, admininistered by a new semi-closed hyperthermic peritoneal perfusion (HPP) technique to patients with peritoneal carcinomatosis. MATERIALS AND METHODS: After surgical cytoreduction, 12 patients were given cisplatin 100 mg/m2 (CDDP), introduced into the HPP circuit for 60 min at 41.7 degrees C and 1200 ml/min flow rate. Perfusate and blood samples were obtained during/after perfusion, plus normal and tumor tissues samples before/after perfusion. RESULTS: Total and ultrafiltrate (UF) CDDP had similar patterns: monophasic in peritoneum, biphasic in plasma. At the end of perfusion, total/UF platinum (Pt) concentrations in the peritoneum decreased by 63.4%-64.9%. Total/UF Pt concentrations and AUCtot in perfusate were higher than plasmatic ones. Pt concentrations in tumor specimens were higher than in normal tissues. CONCLUSION: Cisplatin administered by semi-closed HPP evidenced pharmacological advantages: higher and direct drug exposure of the tumor within the peritoneal cavity, limited systemic absorption and mild toxicity.

Gemcitabine and vinorelbine in recurrent head and neck cancer: pharmacokinetic and clinical results.

OBJECTIVES: To evaluate the pharmacokinetic parameters, efficacy and toxicity of a combination of gemcitabine (GEM) and vinorelbine (VNB) in recurrent heavily pre-treated squamous cell head and neck carcinoma. MATERIALS AND METHODS: Twenty-four patients previously treated with concomitant chemo-radiotherapy (n = 13), surgery plus radiotherapy (n = 10) and surgery + concomitant chemo-radiotherapy (n = 1) were enrolled; 7 patients had received one or more courses of palliative chemotherapy. Twenty patients had a local-regional recurrence and 4 patients had metastases. The doses were 1200 mg/m2 for GEM and 30 mg/m2 for VNB on days 1 and 8 every 21 days; a maximum of 6 cycles was allowed. Pharmacokinetic investigations were performed on 9 patients receiving GEM and VNB. As a PK control, a second group of 5 patients was given GEM as single agent, at the same doses and with the same i.v. infusion length. RESULTS: Twenty-four patients received a total of 135 cycles (median per patient, 5). Neutropenia was the most frequent side-effect (92% of patients; grade 3-4 in 50%). The overall response rate was 25% which included 1 of 24 complete responses (4%) and 4 of 24 partial responses (21%). Responses were observed only in patients with good prognostic characteristics. The median response duration was 5.5 months (2-16 months) and the overall median survival was 9 months (range, 2-25+). Vinorelbine serum levels showed no evidence of any pharmacokinetic interaction with GEM; most of all, no rebound in VNB disposition can be produced by GEM pre-administration. CONCLUSION: The GEM-VNB combination has a palliative role in patients with favourable characteristics; the results seem no better than those observed with VNB alone. Moreover, this drug association does not alter the pharmacokinetic profile of both drugs, also compared to GEM monotherapy.

From conventional to stealth liposomes: a new frontier in cancer chemotherapy.

Many attempts have been made to achieve good selectivity to targeted tumor cells by preparing specialized carrier agents that are therapeutically profitable for anticancer therapy. Among these, liposomes are the most studied colloidal particles thus far applied in medicine and in particular in antitumor therapy. Although they were first described in the 1960s, only at the beginning of 1990s did the first therapeutic liposomes appear on the market. The first-generation liposomes (conventional liposomes) comprised a liposome-containing amphotericin B, Ambisome (Nexstar, Boulder, CO, USA), used as an antifungal drug, and Myocet (Elan Pharma Int, Princeton, NJ, USA), a doxorubicin-containing liposome, used in clinical trials to treat metastatic breast cancer. The second-generation liposomes ("pure lipid approach") were long-circulating liposomes, such as Daunoxome, a daunorubicin-containing liposome approved in the US and Europe to treat AIDS-related Kaposi's sarcoma. The third-generation liposomes were surface-modified liposomes with gangliosides or sialic acid, which can evade the immune system responsible for removing liposomes from circulation. The fourth-generation liposomes, pegylated liposomal doxorubicin, were called "stealth liposomes" because of their ability to evade interception by the immune system, in the same way as the stealth bomber was able to evade radar. Actually, the only stealth liposome on the market is Caelyx/Doxil (Schering-Plough, Madison NJ, USA), used to cure AIDS-related Kaposi's sarcoma, resistant ovarian cancer and metastatic breast cancer. Pegylated liposomal doxorubicin is characterized by a very long-circulation half-life, favorable pharmacokinetic behavior and specific accumulation in tumor tissues. These features account for the much lower toxicity shown by Caelyx in comparison to free doxorubicin, in terms of cardiotoxicity, vesicant effects, nausea, vomiting and alopecia. Pegylated liposomal doxorubicin also appeared to be less myelotoxic than doxorubicin. Typical forms of toxicity associated to it are acute infusion reaction, mucositis and palmar plantar erythrodysesthesia, which occur especially at high doses or short dosing intervals. Active and cell targeted liposomes can be obtained by attaching some antigen-directed monoclonal antibodies (Moab or Moab fragments) or small proteins and molecules (folate, epidermal growth factor, transferrin) to the distal end of polyethylene glycol in pegylated liposomal doxorubicin. The most promising therapeutic application of liposomes is as non-viral vector agents in gene therapy, characterized by the use of cationic phospholipids complexed with the negatively charged DNA plasmid. The use of liposome formulations in local-regional anticancer therapy is also discussed. Finally, pegylated liposomal doxorubicin containing radionuclides are used in clinical trials as tumor-imaging agents or in positron emission tomography.

Synthesis, characterization and transfection activity of new saturated and unsaturated cationic lipids.

We synthesized new cationic lipids, analogue to N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA) and 1,2-dimyristyloxypropyl-3-dimethyl-hydroxyethylammonium bromide (DMRIE), in order to compare those containing a dodecyl chain with those having a relatively long chain with two or five double bonds, such as squalenyl and dihydrofarnesyl derivatives, or complex saturated structures, such as squalane derivatives. The fusogenic helper lipid dioleoylphosphatidylethanolamine (DOPE) was added to cationic lipids to form a stable complex. Liposomes composed of 50:50 w/w cationic lipid/DOPE were prepared and incubated with plasmidic DNA at various charge ratios and the diameter and zeta potential of the complexes were measured. The surface charge of the DNA/lipid complexes can be controlled by adjusting the cationic lipid/DNA ratio. Finally, we tested the in vitro transfection efficiency of the cationic lipid/DNA complexes using different cell lines. The transfection efficiency was highest for the dodecyloxy derivative containing a single hydroxyethyl group in the head, followed by the dodecyloxy and the farnesyloxy trimethylammonium derivatives. Instead the C27 squalenyl and C27 squalanyl derivatives resulted inactive.