Dietary supplementation with n-3-fatty acids in patients with pancreatic cancer and cachexia: marine phospholipids versus fish oil - a randomized controlled double-blind trial.

BACKGROUND: Like many other cancer patients, most pancreatic carcinoma patients suffer from severe weight loss. As shown in numerous studies with fish oil (FO) supplementation, a minimum daily intake of 1.5 g n-3-fatty acids (n-3-FA) contributes to weight stabilization and improvement of quality of life (QoL) of cancer patients. Given n-3-FA not as triglycerides (FO), but mainly bound to marine phospholipids (MPL), weight stabilization and improvement of QoL has already been seen at much lower doses of n-3-FA (0,3 g), and MPL were much better tolerated. The objective of this double-blind randomized controlled trial was to compare low dose MPL and FO formulations, which had the same n-3-FA amount and composition, on weight and appetite stabilization, global health enhancement (QoL), and plasma FA-profiles in patients suffering from pancreatic cancer. METHODS: Sixty pancreatic cancer patients were included into the study and randomized to take either FO- or MPL supplementation. Patients were treated with 0.3 g of n-3-fatty acids per day over six weeks. Since the n-3-FA content of FO is usually higher than that of MPL, FO was diluted with 40% of medium chain triglycerides (MCT) to achieve the same capsule size in both intervention groups and therefore assure blinding. Routine blood parameters, lipid profiles, body weight, and appetite were measured before and after intervention. Patient compliance was assessed through a patient diary. Quality of life and nutritional habits were assessed with validated questionnaires (EORTC-QLQ-C30, PAN26). Thirty one patients finalized the study protocol and were analyzed (per-protocol-analysis). RESULTS: Intervention with low dose n-3-FAs, either as FO or MPL supplementation, resulted in similar and promising weight and appetite stabilization in pancreatic cancer patients. MPL capsules were slightly better tolerated and showed fewer side effects, when compared to FO supplementation. CONCLUSION: The similar effects between both interventions were unexpected but reliable, since the MPL and FO formulations caused identical increases of n-3-FAs in plasma lipids of included patients after supplementation. The effects of FO with very low n-3-FA content might be explained by the addition of MCT. The results of this study suggest the need for further investigations of marine phospholipids for the improvement of QoL of cancer patients, optionally in combination with MCT.

Nutrient limitation governs Staphylococcus aureus metabolism and niche adaptation in the human nose.

Colonization of the human nose by Staphylococcus aureus in one-third of the population represents a major risk factor for invasive infections. The basis for adaptation of S. aureus to this specific habitat and reasons for the human predisposition to become colonized have remained largely unknown. Human nasal secretions were analyzed by metabolomics and found to contain potential nutrients in rather low amounts. No significant differences were found between S. aureus carriers and non-carriers, indicating that carriage is not associated with individual differences in nutrient supply. A synthetic nasal medium (SNM3) was composed based on the metabolomics data that permits consistent growth of S. aureus isolates. Key genes were expressed in SNM3 in a similar way as in the human nose, indicating that SNM3 represents a suitable surrogate environment for in vitro simulation studies. While the majority of S. aureus strains grew well in SNM3, most of the tested coagulase-negative staphylococci (CoNS) had major problems to multiply in SNM3 supporting the notion that CoNS are less well adapted to the nose and colonize preferentially the human skin. Global gene expression analysis revealed that, during growth in SNM3, S. aureus depends heavily on de novo synthesis of methionine. Accordingly, the methionine-biosynthesis enzyme cysteine-γ-synthase (MetI) was indispensable for growth in SNM3, and the MetI inhibitor DL-propargylglycine inhibited S. aureus growth in SNM3 but not in the presence of methionine. Of note, metI was strongly up-regulated by S. aureus in human noses, and metI mutants were strongly abrogated in their capacity to colonize the noses of cotton rats. These findings indicate that the methionine biosynthetic pathway may include promising antimicrobial targets that have previously remained unrecognized. Hence, exploring the environmental conditions facultative pathogens are exposed to during colonization can be useful for understanding niche adaptation and identifying targets for new antimicrobial strategies.

A nasal epithelial receptor for Staphylococcus aureus WTA governs adhesion to epithelial cells and modulates nasal colonization.

Nasal colonization is a major risk factor for S. aureus infections. The mechanisms responsible for colonization are still not well understood and involve several factors on the host and the bacterial side. One key factor is the cell wall teichoic acid (WTA) of S. aureus, which governs direct interactions with nasal epithelial surfaces. We report here the first receptor for the cell wall glycopolymer WTA on nasal epithelial cells. In several assay systems this type F-scavenger receptor, termed SREC-I, bound WTA in a charge dependent manner and mediated adhesion to nasal epithelial cells in vitro. The impact of WTA and SREC-I interaction on epithelial adhesion was especially pronounced under shear stress, which resembles the conditions found in the nasal cavity. Most importantly, we demonstrate here a key role of the WTA-receptor interaction in a cotton rat model of nasal colonization. When we inhibited WTA mediated adhesion with a SREC-I antibody, nasal colonization in the animal model was strongly reduced at the early onset of colonization. More importantly, colonization stayed low over an extended period of 6 days. Therefore we propose targeting of this glycopolymer-receptor interaction as a novel strategy to prevent or control S. aureus nasal colonization.

Lactate as a novel quantitative measure of viability in Schistosoma mansoni drug sensitivity assays.

Whole-organism compound sensitivity assays are a valuable strategy in infectious diseases to identify active molecules. In schistosomiasis drug discovery, larval-stage Schistosoma allows the use of a certain degree of automation in the screening of compounds. Unfortunately, the throughput is limited, as drug activity is determined by manual assessment of Schistosoma viability by microscopy. To develop a simple and quantifiable surrogate marker for viability, we targeted glucose metabolism, which is central to Schistosoma survival. Lactate is the end product of glycolysis in human Schistosoma stages and can be detected in the supernatant. We assessed lactate as a surrogate marker for viability in Schistosoma drug screening assays. We thoroughly investigated parameters of lactate measurement and performed drug sensitivity assays by applying schistosomula and adult worms to establish a proof of concept. Lactate levels clearly reflected the viability of schistosomula and correlated with schistosomulum numbers. Compounds with reported potencies were tested, and activities were determined by lactate assay and by microscopy. We conclude that lactate is a sensitive and simple surrogate marker to be measured to determine Schistosoma viability in compound screening assays. Low numbers of schistosomula and the commercial availability of lactate assay reagents make the assay particularly attractive to throughput approaches. Furthermore, standardization of procedures and quantitative evaluation of compound activities facilitate interassay comparisons of potencies and, thus, concerted drug discovery approaches.

Temporal expression of adhesion factors and activity of global regulators during establishment of Staphylococcus aureus nasal colonization.

The human pathogen Staphylococcus aureus successfully colonizes its primary reservoir, the nasal cavity, most likely by regulatory adaptation to the nose environment. Cotton rats represent an excellent model for the study of bacterial gene expression in the initial phases of colonization. To gain insight into the expression profile necessary for the establishment of colonization, we performed direct transcript analysis by quantitative real-time reverse-transcription polymerase chain reaction on cotton rat noses removed from euthanized animals on days 1, 4, or 10 after instillation of 2 human S. aureus nose isolates. Global virulence regulators (agr, sae) were not active in this early phase, but the essential 2-component regulatory system WalKR seems to play an important role. Accordingly, an elevated expression of walKR target genes (sak, sceD) could be detected. In agreement with previous studies that demonstrated the essential role played by wall teichoic acid (WTA) polymers in nasal colonization, we detected a strongly increased expression of WTA-biosynthetic genes. The expression profile switched to production of the adhesive proteins ClfB and IsdA at later stages of the colonization process. These data underscore the temporal differences in the roles of WTA and surface proteins in nasal colonization, and they provide the first evidence for a regulation of WTA biosynthesis in vivo.

Marine phospholipids--a promising new dietary approach to tumor-associated weight loss.

GOALS OF WORK: Advanced tumor disease very often evokes excessive loss of body weight. Among others, fish oil or marine fatty acid ethyl esters were investigated for treatment of cancer cachexia with controversial results. In this study, a new formulation of marine fatty acids was investigated, the marine phospholipids, with more than 50% of phospholipid-bound fatty acids being eicosapentaenoic and docosahexaenoic acid. MATERIALS AND METHODS: Thirty-one tumor patients with various tumor entities suffering from weight loss were asked to take marine phospholipids (1.5 g/day) as softgel capsules for a period of 6 weeks. Compliance, body weight, appetite, and quality of life as well as the fatty acid profile in plasma and blood cells were monitored; 17 patients could be analyzed. MAIN RESULTS: Marine phospholipids were very well accepted; low-dose supplementation resulted in a significant increase of eicosapentaenoic and docosahexaenoic acid in plasma phospholipids; therefore, significantly reducing the n-6 to n-3 fatty acid ratio. A stabilization of body weight was achieved (median weight change of +0.6% after 6 weeks), while appetite and quality of life improved. CONCLUSIONS: These promising first results encourage further investigation of marine phospholipids in cancer care.

Liposomal gemcitabine (GemLip)-efficient drug against hormone-refractory Du145 and PC-3 prostate cancer xenografts.

BACKGROUND: Gemcitabine (Gemc) is an efficient chemotherapeutic drug in various cancer types (e.g., pancreas) but has only limited effects on hormone-refractory prostate cancer (HRPCa). Since HRPCa cells are highly sensitive to even low doses of Gemc in vitro, the lack of clinical effects might be due to rapid degradation of Gemc by deaminases combined with impaired accumulation in tumor tissue and PCa cells. Liposomal formulation (GemLip) is expected to protect the entrapped cytotoxic substance from enzymatic degradation and furthermore augment its accumulation within tumor tissues due to an enhanced permeability of the tumor vessels. METHODS: Anti-tumoral and anti-metastatic activity of GemLip and Gemc were investigated in two luciferase-expressing, human hormone-refractory PC-3 and Du145 HRPCa xenograft models in immunodeficient mice. Tumor growth was monitored by in vivo luminescence imaging (orthotopic) or callipering (subcutaneous). Anti-metastatic effects of treatment were determined by in vitro luciferase assay of the tissues. RESULTS: Tumor growth of subcutaneous Du145 xenografts was significantly inhibited only by GemLip (8 mg/kg: P = 0.014 and 6 mg/kg: P = 0.011) but not by conventional Gemc (360 mg/kg). In contrast, growth of orthotopic PC-3 xenografts was significantly inhibited by both, GemLip (P = 0.041) and Gemc (P = 0.002). The drugs furthermore strongly reduced spleen and liver metastases in this model. CONCLUSIONS: As shown by the very low efficient concentration of GemLip, liposomal entrapment of Gemc greatly enhances its activity. GemLip has, even at very low doses, a significant anti-tumoral and anti-metastatic therapeutic effect in HRPCa xenografts in vivo and was beneficial even when the conventional Gemc failed.

Phase II STUdy with 3rd- or 4th-line bendamustine (flat dose) therapy in patients with metastatic breast cancer.

BACKGROUND: Bendamustine is a drug with a favorable side effect spectrum and it offers a chance to overcome tumor resistance in pretreated patients with metastatic breast cancer (MBC). PATIENTS AND METHODS: Bendamustine was given as flat dose with 200 mg at days 1 + 2 in MBC patients pretreated with 2-3 different chemotherapies. Therapy was repeated at day 28 or fully recovered neutrophils. After 2 treatment cycles, a tumor response evaluation was performed. Toxicity was graded according to the National Cancer Institute common toxicity criteria (NCI-CTC) catalogue. RESULTS: 22 patients were evaluated for toxicity. 4 patients dropped out before the first tumor response evaluation; thus, 18 patients were evaluable for anticancer efficacy evaluation. 3/18 patients reached a partial remission (PR), 4 stable disease and 11 showed progression after 2 treatment cycles. The time to progression (TTP) was 5 months in patients with PR and 4 months in patients with no change (NC). In patients with progressive disease (PD), TTP was < 2 months. The main toxicities were nausea, weight loss and fatigue. CONCLUSIONS: Bendamustine can be given with a fixed flat dose, which simplifies the drug preparation. 2/5th of all treated patients responded to this therapy whereas bendamustine showed no anticancer effect in 3/5th of all patients. Bendamustine is definitely a drug with anticancer potential.

Synthesis and biological evaluation of an albumin-binding prodrug of doxorubicin that is cleaved by prostate-specific antigen (PSA) in a PSA-positive orthotopic prostate carcinoma model (LNCaP).

The prostate-specific antigen (PSA) is a serine protease that is over-expressed in prostate carcinoma and represents a molecular target for selectively releasing an anticancer agent from a prodrug formulation. We have recently investigated a macromolecular prodrug strategy for improved cancer chemotherapy based on 2 features: (i) rapid and selective binding of thiol-reactive prodrugs to the cysteine-34 position of endogenous albumin after intravenous administration, and (ii) enzymatic release of the albumin-bound drug at the tumor site (Mansour et al., Cancer Res 2003, 63, 4062-4066). In this work, we describe an albumin-binding prodrug, EMC-Arg-Ser-Ser-Tyr-Tyr--Ser-Arg-DOXO [EMC: epsilon-Maleimidocaproic acid; DOXO = doxorubicin; X = amino acid] that is cleaved by PSA. Because of the incorporation of 2 arginine residues, the prodrug exhibited excellent water-solubility and was rapidly and selectively bound to endogenous albumin. Incubation studies with PSA and tumor homogenates from PSA-positive tumors (LNCaP) demonstrated that the albumin-bound form of the prodrug was efficiently cleaved by PSA at the P(1)-P' (1) scissile bond releasing the doxorubicin dipeptide H-Ser-Arg-DOXO, which was further degraded to doxorubicin as the final cleavage product. In cell culture experiments, the prodrug was approximately 100-fold less active against LNCaP cells than the free drug. In contrast, in a mouse model of human prostate cancer using luciferase transduced LNCaP cells orthotopically implanted in SCID mice, the prodrug showed enhanced antitumor efficacy when compared to doxorubicin. Doxorubicin treatment at a dose of 2 x 4 mg/kg caused significant weight loss and mortality (-25%), and did not result in a significant antitumor response at the end of the experiment. The prodrug at 3 x 12 mg/kg doxorubicin equivalents, however, was well tolerated and induced a significant reduction in tumor size of 62% (+/-25%, **p = 0.003) as well as a decrease of the metastatic burden in the lungs as detected in luciferase assays (-50%, SD +/- 115%, *p = 0.038).

Antitumoral and antiangiogenic efficacy of bisphosphonates in vitro and in a murine RENCA model.

BACKGROUND: Bisphosphonates have shown direct antitumoral activity in vitro, in vivo and even in clinical studies, but the exact mechanism for this has not yet been elucidated. In this study the antiangiogenic potency of zoledronic acid and clodronate were evaluated. MATERIALS AND METHODS: The effects of zoledronic acid and clodronate on the proliferation of endothelial cells and different tumor cells, and on the activity of protein kinases were investigated. Furthermore in vitro experiments were performed to evaluate the underlying antiangiogenic mechanism of action. Both bisphosphonates were examined in vivo at different doses and in daily subcutaneous application in a murine renal cell carcinoma model (RENCA). The antiangiogenic activity was evaluated by immunohistochemical staining (CD31) and by determination of mouse vascular endothelial growth factor (VEGF) serum concentration. RESULTS: Zoledronic acid and clodronate inhibited proliferation of endothelial cells at lower concentrations than the different tumor cell lines did. This effect was more pronounced for zoledronic acid. The activity of almost all tested kinases was inhibited by zoledronic acid, whereas clodronate showed no effect. In the RENCA model, a significant effect of zoledronic acid on the primary tumor in a bell-shaped dose response curve with the highest efficacy between 100 Bg/kg 2xd and 200 Bg/kg 1xd, was observed. The mean vessel density (MVD) was significantly reduced by both bisphosphonates at different concentrations. This is the first report on increased mouse VEGF serum concentrations in the RENCA model. CONCLUSION: The results indicate that these bisphosphonates, particularly zoledronic acid, possess antitumoral and antiangiogenic activity.

IFN-y enhances T(H)1 polarisation of monocyte-derived dendritic cells matured with clinical-grade cytokines using serum-free conditions.

Using serum-free conditions, human monocyte-derived dendritic cells (MoDCs) tend to mature insufficiently in a T(H)1-polarizing direction under approved and standardized clinical conditions. However, for the initiation of an efficient tumour antigen-specific cytotoxic T-cell response, the induction of a distinct T(H)1 response is favourable. Therefore, to improve T(H)1 polarisation, the influence of interferon-gamma (IFN-gamma) on the maturation of MoDCs was investigated with clinical-grade cytokines or lipopolysaccharide (LPS) in serum-free medium focusing on the viability, phenotypic characteristics, cytokine profile and restimulating capacities. As in previous research, we confirmed that in respect of viability and phenotypic characteristics, cytokine cocktails consisting of tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6 and prostaglandin (PG) E2, mature MoDCs most efficiently. However, these cytokine-matured MoDCs secreted relatively high levels of IL-10 and only low levels of IL-12p70. Remarkably, if IFN-gamma was added, significantly lower levels of IL-10 concomitant with higher levels of IL-12p70 could be detected. Pretreatment with IFN-gamma did not improve the phenotypic characteristics nor the T(H)1 polarisation of MoDCs. Nevertheless, MoDCs matured with clinical-grade cytokines and IFN-gamma could be re-stimulated most effectively with IFN-gamma. In conclusion, our work demonstrates that addition of INF-gamma to clinical-grade cytokine cocktails readily matures MoDCs and enhances their T(H)1 polarisation efficiently under serum-free conditions.

Phase I and pharmacokinetic study of the (6-maleimidocaproyl)hydrazone derivative of doxorubicin.

PURPOSE: The (6-maleimidocaproyl)hydrazone derivative of doxorubicin (DOXO-EMCH) is an albumin-binding prodrug of doxorubicin with acid-sensitive properties that shows superior antitumor efficacy in murine tumor models and a favorable toxicity profile in mice, rats, and dogs compared with doxorubicin. The purpose of the phase I study was to characterize the toxicity profile of DOXO-EMCH, establish a recommended dose for phase II studies, and assess potential anticancer activity. EXPERIMENTAL DESIGN: A starting dose of 20 mg/m2 doxorubicin equivalents was chosen. Forty-one patients with advanced cancer disease were treated with an i.v. infusion of DOXO-EMCH once every 3 weeks at a dose level of 20 to 340 mg/m2 doxorubicin equivalents. RESULTS: Treatment with DOXO-EMCH was well tolerated up to 200 mg/m2 without manifestation of drug-related side effects. Myelosuppression (grade 1-2) and mucositis (grade 1-2) were the predominant adverse effects at dose levels of 260 mg/m2 and myelosuppression (grade 1-3) as well as mucositis (grade 1-3) were dose limiting at 340 mg/m2. No cardiac toxicity was observed. Of 30 of 41 evaluable patients, 12 patients (40%) had progressive disease, 15 patients (57%) had stable disease, and 3 patients (10%) had a partial remission. CONCLUSIONS: DOXO-EMCH showed a good safety profile and was able to induce tumor regressions in tumor types known to be anthracycline-sensitive tumors, such as breast cancer, small cell lung cancer, and sarcoma. The recommended doxorubicin equivalent dose for phase II studies is 260 mg/m2.

Plasma lyso-phosphatidylcholine concentration is decreased in cancer patients with weight loss and activated inflammatory status.

BACKGROUND: It has been observed that ras-transformed cell lines in culture have a higher phosphatidylcholine (PC) biosynthesis rate as well as higher PC-degradation rate (increased PC-turnover) than normal cells. In correspondence to these findings, the concentrations of the PC-degradation product lyso-phosphatidylcholine (LPC) in cancer patients were found to be decreased. Our objective was the systematic investigation of the relationship between LPC and inflammatory and nutritional parameters in cancer patients. Therefore, plasma LPC concentrations were assessed in 59 cancer patients and related to nutritional and inflammatory parameters. To determine LPC in blood plasma we developed and validated a HPTLC method. RESULTS: Average plasma LPC concentration was 207 +/- 59 microM which corresponds to the lower limit of the reported range in healthy subjects. No correlation between LPC and age, performance status, body mass index (BMI) or fat mass could be seen. However, LPC correlated inversely with plasma C-reactive protein (CRP) and whole blood hydrogen peroxides (HPO). Further, a negative correlation could be observed between LPC and whole body extra cellular fluid volume (ECF) as well as with relative change in body weight since cancer diagnosis. CONCLUSION: In conclusion, LPC concentrations were decreased in cancer patients. LPC plasma concentrations correlated with weight loss and inflammatory parameters and, therefore, might be a general indicator of severity of malignant disease.

Metronomic antiangiogenic therapy with capecitabine and celecoxib in advanced tumor patients--results of a phase II study.

BACKGROUND: Combined therapy of continuous low dose capecitabine and high dose celecoxib targeting angiogenesis was used in a phase II trial to treat advanced cancer patients. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was used to monitor antiangiogenic effects. MATERIAL AND METHODS: 37 Patients (21 men, 16 women), mean age 60 years, with advanced and progressive cancer of various tumor types were included. Therapy consisted of 2 x 500 mg oral capecitabine/ day and 2 x 400 mg oral celecoxib/day continuously until progression of disease. To monitor antiangiogenic effects, DCE-MRI measurements were performed at baseline, after 1 month, and after 3 months of therapy. Tumor assessment was performed according to RECIST criteria, toxicity was evaluated according to the CTC version 2.0 catalogue. RESULTS: Therapy was well tolerated without grade 3 and 4 toxicities. The mean number of treatment cycles was 4 (range: 1-15+). Disease stabilization after 3 cycles was seen in 11 patients. 6 patients were stable over long periods. The mean number of treatment cycles in this group was 10 (range: 7-15+). DCE-MRI demonstrated a reduction of tumor vessel permeability and blood flow in patients who reached stable disease or some minor regression. CONCLUSION: Continuous dosing of the combination of capecitabine and celecoxib was well tolerated, produced antiangiogenic effects, and has antitumor activity. Patients with rapid progression did not benefit.

Cytotoxic efficacy and influence on cellular phospholipid metabolism of 2-hydroxy- and 2-O-acetyl-octadecylphosphocholines.

The cytotoxic efficacy and influence on phospholipid composition of the new alkylphosphocholines (APC) 2-hydroxy and 2-O-acetyl-octadecylphosphocholines both synthesised in R- and S-configuration (R/S-OH and R/S-O-acetyl) were examined in vitro using HL-60 and MDA-MB-468 cells. IC50- and LC50-values were measured by MTT- and cell count assay. All tested APC showed higher or similar cytotoxic efficacy compared to the well known APC hexadecylphosphocholine (HePC). However, while S-configured APC (IC50) revealed considerably higher cytotoxic activities, only R- (natural)-configured APC caused significant changes in the phospholipid composition of tumour cells. Further investigations revealed an increase in R-O-acyl and loss of PC up to 70% in the membrane of both cell lines. Similar to PC, R-O-acyl bears two long non-polar hydrocarbon chains and stabilises cell membranes structurally, thus, possibly explaining less cytotoxicity and lack of apoptosis induction by R-configured APC. Nevertheless, an enrichment of R-O-acyl up to 70% at the expense of PC in cell membrane is tremendous and may inhibit tumour development by influencing the intracellular lipid signalling. In conclusion, our findings reveal the antitumoral efficacy of all tested new APC and offer new perspectives in drug development targeting phospholipid metabolism.

Association of Paclitaxel pharmacokinetics with the development of peripheral neuropathy in patients with advanced cancer.

PURPOSE: The shortening of infusion time from 3 to 1 hour decreases the systemic exposure (area under the curve, AUC) of total and unbound paclitaxel but increases the AUC of its vehicle Cremophor EL, whereas the time above total paclitaxel concentrations of 0.05 micromol/L (T >0.05) remains almost constant. As both Cremophor EL and paclitaxel are neurotoxic, we evaluated their pharmacodynamic effects on the development of peripheral neuropathy as the most important nonhematologic toxicity. EXPERIMENTAL DESIGN: Patients with advanced cancer of different origin were randomized to receive a maximum of 12 weekly-given 1- or 3-hour infusions of 100 mg/m2 paclitaxel (Taxol). Twenty-four patients were assessable for both pharmacokinetics and peripheral neuropathy development evaluated by a clinical scoring system including sensory symptoms, strength, tendon reflexes, and vibratory sense. RESULTS: Patients with peripheral neuropathy development (n=14) received more weeks of therapy (P=0.056) and showed significantly higher T(>0.05) (P=0.022) and overall systemic drug exposures (weeks of therapy x AUC) for total paclitaxel (P=0.002) and unbound paclitaxel (P=0.003) than those without peripheral neuropathy. In Kaplan-Meier analyses, T(>0.05) > or = 10.6 hours (P=0.023), AUC of total paclitaxel > or = 4.7 microg/mL x hour (P = 0.047), and AUC of unbound paclitaxel > or = 0.375 microg/mL x hour (P = 0.095) were identified as being potential factors for peripheral neuropathy development. In a Cox regression analysis, only T(>0.05) > or = 10.6 hours remained as an independent risk factor (relative risk, 18.43; P = 0.036) after adjusting for prior vincamycin (relative risk, 11.28; P = 0.038). CONCLUSIONS: From the results obtained in this study, it is concluded that exposure to paclitaxel but not Cremophor EL is associated with peripheral neuropathy development.

A new approach for the treatment of malignant melanoma: enhanced antitumor efficacy of an albumin-binding doxorubicin prodrug that is cleaved by matrix metalloproteinase 2.

The progression of malignant melanoma is characterized by overexpression of a number of matrix metalloproteinases (MMPs), especially MMP-2, which play a critical role in the degradation of basement membranes and the extracellular matrix. Consequently, we assessed a drug targeting strategy in which the protease activity of MMP-2 is exploited to release an anticancer agent from a macromolecular carrier, i.e., circulating albumin. For this purpose, a water-soluble maleimide derivative of doxorubicin (1) incorporating a MMP-2 specific peptide sequence (Gly-Pro-Leu-Gly-Ile-Ala-Gly-Gln) was developed that binds rapidly and selectively to the cysteine-34 position of circulating albumin. The albumin-bound form of 1 was efficiently and specifically cleaved by MMP-2 liberating a doxorubicin tetrapeptide (Ile-Ala-Gly-Gln-DOXO) and subsequently doxorubicin. In vivo, 1 was superior to the parent compound doxorubicin in the A375 human melanoma xenograft, which is characterized by a high expression of MMP-2.

PTK787/ZK 222584, a specific vascular endothelial growth factor-receptor tyrosine kinase inhibitor, affects the anatomy of the tumor vascular bed and the functional vascular properties as detected by dynamic enhanced magnetic resonance imaging.

Antiangiogenic therapy is a promising new strategy of inhibiting tumor growthand formation of metastases. Recently, a number of compounds with different effects on tumor endothelial cells have entered clinical trials and revealed the need for diagnostic methods to detect their biological activity. Dynamic enhanced magnetic resonance imaging (dyMRI) is used in most clinical trials with antiangiogenic active compounds. We evaluated this method by using PTK787/ZK 222584, a specific inhibitor of the VEGF-receptor tyrosine kinases, which showed antitumoral and antiangiogenic activity in a murine renal cell carcinoma (RENCA) model. After intrarenal application of RENCA cells, mice developed a primary tumor and metastases to the lung and abdominal lymph nodes. After daily oral therapy for 21 days with either PTK787/ZK 222584 at a dose of 50 mg/kg or vehicle, primary tumors of all animals were analyzed by dyMRI. Gadolinium-DOTA (Dotarem) was used as a contrast agent to detect vessel permeability and contrast agent extravasation, whereas intravascular iron oxide nanoparticles (Endorem) were used to detect partial tumor blood volume. Additionally, vessel density, architecture, diameter, and blood flow velocity were investigated by appropriate methods. Surprisingly, no changes in extravasation occurred under treatment with PTK787/ZK 222584 as compared with the control group, whereas a significant decrease in vessel permeability occurred. Furthermore, an increase in partial blood volume was found in the PTK787/ZK 222584-treated group, although vessel density was reduced as seen by histology. Using the corrosion cast technique, reduction in vessel density was significant but not very pronounced and predominantly attributable to the loss of microvessels only. This finding correlated with a shift to large vessel diameters in the primary tumors of PTK787/ZK 222584-treated animals and with reduction of blood flow velocity in the tumor feeding renal artery. From these findings, we conclude that the treatment with PTK787/ZK 222584 primarily reduces the number of tumor microvessels, accompanied by a hemodynamic dilation of the remaining vessels. This dilation could influence the result of dyMRI such that no change in extravasation or even an increase in partial tumor blood volume could be observed.

Dynamic contrast-enhanced magnetic resonance imaging as a biomarker for the pharmacological response of PTK787/ZK 222584, an inhibitor of the vascular endothelial growth factor receptor tyrosine kinases, in patients with advanced colorectal cancer and liver metastases: results from two phase I studies.

PURPOSE: PTK787/ZK 222584 (PTK/ZK), an orally active inhibitor of vascular endothelial growth factor (VEGF) receptor tyrosine kinases, inhibits VEGF-mediated angiogenesis. The pharmacodynamic effects of PTK/ZK were evaluated by assessing changes in contrast-enhancement parameters of metastatic liver lesions using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in patients with advanced colorectal cancer treated in two ongoing, dose-escalating phase I studies. PATIENTS AND METHODS: Twenty-six patients had DCE-MRI performed at baseline, day 2, and at the end of each 28-day cycle. Doses of oral PTK/ZK ranged from 50 to 2000 mg once daily. Tumor permeability and vascularity were assessed by calculating the bidirectional transfer constant (Ki). The percentage of baseline Ki (% of baseline Ki) at each time point was compared with pharmacokinetic and clinical end points. RESULTS: A significant negative correlation exists between the % of baseline Ki and increase in PTK/ZK oral dose and plasma levels (P =.01 for oral dose; P =.0001 for area under the plasma concentration curve at day 2). Patients with a best response of stable disease had a significantly greater reduction in Ki at both day 2 and at the end of cycle 1 compared with progressors (mean difference in % of baseline Ki, 47%, P =.004%; and 51%, P =.006; respectively). The difference in % of baseline Ki remained statistically significant after adjusting for baseline WHO performance status. CONCLUSION: These findings should help to define a biologically active dose of PTK/ZK. These results suggest that DCE-MRI may be a useful biomarker for defining the pharmacological response and dose of angiogenesis inhibitors, such as PTK/ZK, for further clinical development.

Phase I clinical and pharmacokinetic study of PTK/ZK, a multiple VEGF receptor inhibitor, in patients with liver metastases from solid tumours.

The family of VEGF receptors are important mediators of angiogenesis, which is essential for tumour growth and metastasis. PTK/ZK is a multiple VEGF receptor inhibitor that blocks the activity of all known VEGF receptor tyrosine kinases. This phase I/II trial evaluated the safety, pharmacokinetics and efficacy of PTK/ZK in patients with liver metastases from solid tumours. Patients were administered oral PTK/ZK monotherapy once daily at doses of 300-1200 mg/day in 28-day cycles until unacceptable toxicity or tumour progression occurred. Twenty-seven patients were enrolled and treatment with PTK/ZK was generally well tolerated. The most frequently reported adverse events were fatigue, nausea, dizziness, and vomiting (mostly National Cancer Institute Common Toxicity Criteria grade 1 or 2). The area under the concentration-time curve (AUC) of PTK/ZK increased between 300 and 1000 mg/day with no further increase from 1000 to 1200 mg/day; the AUC decreased by 50% between day 1 and day 15. The DCE-MRI showed a statistically significant early reduction of tumour blood supply (measured as Ki) at day 2 at doses > or = 750 mg/day. Disease progression was significantly correlated with percent change from baseline Ki. Thirteen patients had stable disease for at least two cycles (56 days). Median overall survival was 11.8 months (95% CI = 6.6, 17.1 months). Long-term therapy with PTK/ZK demonstrated predictable pharmacokinetics, was safe and feasible in patients with metastatic disease, and showed promising clinical activity. The minimum biologically active dose was established at 750 mg/day whereas the recommended dose for phase III studies is 1200 mg/day.