Massimo Zucchetti

Role of Macrophage Targeting in the Antitumor Activity of Trabectedin

There is widespread interest in macrophages as a therapeutic target in cancer. Here, we demonstrate that trabectedin, a recently approved chemotherapeutic agent, induces rapid apoptosis exclusively in mononuclear phagocytes. In four mouse tumor models, trabectedin caused selective depletion of monocytes/macrophages in blood, spleens, and tumors, with an associated reduction of angiogenesis. By using trabectedin-resistant tumor cells and myeloid cell transfer or depletion experiments, we demonstrate that cytotoxicity on mononuclear phagocytes is a key component of its antitumor activity. Monocyte depletion, including tumor-associated macrophages, was observed in treated tumor patients. Trabectedin activates caspase-8-dependent apoptosis; selectivity for monocytes versus neutrophils and lymphocytes is due to differential expression of signaling and decoy TRAIL receptors. This unexpected property may be exploited in different therapeutic strategies.

Do anticancer agents reach the tumor target in the human brain

SummaryThe development of effective chemotherapy for tumors of the central nervous system (CNS) is complicated in that the blood-brain barrier (BBB) hampers the penetration of most drugs into the brain and cerebrospinal fluid (CSF). This review summarizes the main reports on the distribution to CNS tumors and peritumoral normal brain of antitumor agents such as epipodophyllotoxins,cis-diamminedichloroplatinum(II), some nitrosoureas, bleomycin, vinblastine, and other clinically used antitumor agents as well as that of some experimental compounds with specific physicochemical properties. Drug levels were measured at surgical resection or in autopsy samples taken from patients who presented with different primary brain tumors or with brain metastases from extracerebral tumors. The observations made in each study were summarized in some detail, and the main points were then evaluated comparatively so as to highlight common aspects in the pharmacokinetic patterns of antitumor agents in human CNS tumors. Independently of their physicochemical properties, most antitumor agents appear to accumulate to a greater extent and to persist longer in intracerebral tumors than in the normal peritumoral brain. From in vitro cytotoxicity assays, it appears that epipodophyllotoxins, platinum compounds, bleomycin, and nitrosoureas reach potentially active therapeutic concentrations at the tumor target. However, all drugs have difficulty in reaching brain tissue adjacent to the tumor, as the intact BBB hampers their penetration. Plasma and CSF drug concentrations usually give little useful indication of the absolute quantity of drugs in brain tumors. To obtain a clear understanding of the CNS distribution of antitumor agents, one must determine whether the compound being measured is actually responsible for the observed activity and must consider the role of metabolites in the effect of the parent drug.

Pharmacokinetics of Anticancer Agents in Patients with Impaired Liver Function

This report reviews published information on the clinical pharmacokinetics of antitumour agents in patients with liver dysfunction, associated with primary liver disease or liver metastases. Information was available for anthracyclines and their related compounds, antimetabolites, cyclophosphamide, vinca alkaloids, taxanes and epipodophyllotoxins. Changes in the pharmacokinetic profile or metabolism in patients with mild or severe hepatobiliary dysfunction are described and the relationships between serum levels, parameters employed for measuring hepatic function and toxic or therapeutic effects are examined. Current knowledge of the pharmacokinetics of antineoplastic agents in liver disease is far from complete, mostly obtained in small numbers of non-homogeneous patients often presenting only moderate liver dysfunction, and empirical guidelines for dose assessment are still largely applied in clinical practice. Because of the complex pathophysiological mechanisms of liver insufficiency in cancer patients, there is still doubt whether endogenous markers are useful. Although caution in treating cancer patients with liver insufficiency is compulsory, for most compounds there seems no need to recommend dose reductions for moderate impairment. However, for the tubulin acting agents, vincristine, vinblastine and possibly for paclitaxel and docetaxel, there is strong evidence that dose adjustment is mandatory in order to avoid excessive neutropenia and neurotoxicity.

Chemical characterization of Iraqi propolis samples and assessing their antioxidant potentials.

Propolis samples, collected from different geographical locations in Iraq (Baghdad, Dahuk, Mosul and Salah ad-Din), were analyzed and assessed for their anti-oxidant activity. Concentrations of phenolic compounds (flavonoids, phenolic acids and their esters) in propolis were estimated using high performance liquid chromatography coupled to electrospray mass spectrometry. Thirty-eight different compounds were identified and 33 of them were polyphenols. Other compounds were tentatively identified as clerodane diterpenoids, and one was considered unknown. Semi-quantitative measurements showed that phenolic acids and their esters were the predominant constituents in propolis extracts, followed by flavones and flavonols, and then flavanones and dihydroflavonols. Propolis samples were further spectrophotometrically characterized using the Folin-Ciocalteu reagent for the determination of total phenolic compounds. The free radical scavenging activities of propolis samples were also evaluated by using the 2,2-diphenyl-1-picrylhydrazyl assay. The results revealed that propolis extracts exhibited strong free radical scavenging activity.

High-performance liquid chromatography tandem mass spectrometry procedure with automated solid phase extraction sample preparation for the quantitative determination of paclitaxel (Taxol®) in human plasma

A sensitive, specific, accurate and reproducible analytical method was developed and validated for the quantitation of the anticancer agent paclitaxel in human plasma. This procedure is based on high performance liquid chromatography/ion spray-tandem mass spectrometry. This methodology is highly specific because a MS/MS technique (multiple reactant-ion monitoring, MRM) was used for both paclitaxel and its internal standard. The use of a fully automated solid phase extraction procedure, using a CN Sep-pak cartridge, to improve the detection limit and quantification limit of paclitaxel in human plasma samples, was evaluated. The method involves the addition of methyl-paclitaxel as internal standard (i.s.). The retention times of paclitaxel and the I.S. were 2.8 and 4.0 min., respectively. The assay was linear over the range 5 to 500 ng/mL, with a quantification limit of 5 ng/mL having a coefficient of variation (c.v.) < 10%. Standard calibration curves, performed on three different days, had correlation coefficients always greater than 0.998. The intra and inter-day precision were within 12%, and accuracy was included in the range 102-110%. Paclitaxel recovery assessed at 15,250 and 500 ng/mL, was determined to be greater than 85%. The assay is applicable to clinical pharmacokinetic studies.

Phase I clinical and pharmacokinetic study of trabectedin and doxorubicin in advanced soft tissue sarcoma and breast cancer

The combination of trabectedin (T) and doxorubicin (D) was brought into clinical development in soft tissue sarcoma (STS) and advanced breast cancer (ABC) because of its in vitro and in vivo additive anti-tumour effect, the fact that there are no overlapping toxicities and the anti-tumour activity of T in those tumours. Feasibility and anti-tumour activity of T+D administered every 3 weeks were evaluated in 38 patients (STS=29, ABC=9) untreated for advanced disease. D was given at 60 mg/m(2) and T at escalating doses from 600 to 800 microg/m(2), which was the maximum tolerated dose due to dose-limiting febrile neutropenia and asthenia. The recommended dose--given to 18 patients in total--was 700 microg/m(2) T with 60 mg/m(2) D. The pharmacokinetic profile of T and D at cycle 1 was analysed in 20 patients. The most common toxicities included a severe but reversible ASAT/ALAT increase (94%), nausea/vomiting, neutropenia, asthenia/fatigue, stomatitis. Partial response and stable disease were assessed in 18% and 56% of STS patients and in 55% and 33% of ABC patients. No pharmacokinetic interaction between T and D was observed. The lack of cumulative toxicity and related complications and the promising activity in STS support further development of T+D.

A first in human phase I study of the proteasome inhibitor CEP-18770 in patients with advanced solid tumours and multiple myeloma

BACKGROUND The safety, pharmacokinetics (PK) and pharmacodynamics of CEP-18770, a new peptide boronic acid proteasome inhibitor, have been investigated after intravenous administration on days 1, 4, 8 and 11 of every 21d cycle in patients with solid tumours and multiple myeloma (MM). PATIENTS AND METHODS Thirty-eight patients were treated with CEP-18770 at escalating doses from 0.1 to 1.8mg/m(2) where 2 out of 5 patients showed dose limiting toxicities. The maximum tolerated/recommended dose (MTD/RD) of 1.5mg/m(2) was tested in 12 additional patients. Skin rash was dose-limiting and occurred in 53% of patients; other frequent toxicities were asthenia (29%), stomatitis (21%) and pyrexia (16%). No significant peripheral neuropathy was observed. PK in plasma was linear with a half-life of the elimination phase of 62.0±43.5h. Proteasome inhibition in peripheral blood mononuclear cells was dose related in MM patients; it was of 45.4±11.5% at the RD. CONCLUSIONS CEP-18770 showed a favourable safety profile with lack of neurotoxicity and linear plasma PK. The definition of the optimal biological dose and schedule of treatment is actively pursued because of the high incidence of skin toxicity of the twice a week schedule.

Tumor Delivery of Chemotherapy Combined with Inhibitors of Angiogenesis and Vascular Targeting Agents

Numerous angiogenesis-vascular targeting agents have been admitted to the ranks of cancer therapeutics; most are used in polytherapy regimens. This review looks at recent progress and our own preclinical experience in combining angiogenesis inhibitors, mainly acting on VEGF/VEGFR pathways, and vascular targeting agents with conventional chemotherapy, discussing the factors that determine the outcome of these treatments. Molecular and morphological modifications of the tumor microenvironment associated with drug distribution and activity are reviewed. Modalities to improve drug delivery and strategies for optimizing combination therapy are examined.

Sequence dependent antitumour efficacy of the vascular disrupting agent ZD6126 in combination with paclitaxel

The clinical success of small-molecule vascular disrupting agents (VDAs) depends on their combination with conventional therapies. Scheduling and sequencing remain key issues in the design of VDA–chemotherapy combination treatments. This study examined the antitumour activity of ZD6126, a microtubule destabilising VDA, in combination with paclitaxel (PTX), a microtubule-stabilising cytotoxic drug, and the influence of schedule and sequence on the efficacy of the combination. Nude mice bearing MDA-MB-435 xenografts received weekly cycles of ZD6126 (200 mg kg−1 i.p.) administered at different times before or after PTX (10, 20, and 40 mg kg−1 i.v.). ZD6126 given 2 or 24 h after PTX showed no significant benefit, a result that was attributed to a protective effect of PTX against ZD6126-induced vascular damage and tumour necrosis, a hallmark of VDA activity. Paclitaxel counteracting activity was reduced by distancing drug administrations, and ZD6126 given 72 h after PTX potentiated the VDAs antitumour activity. Schedules with ZD6126 given before PTX improved therapeutic activity, which was paralleled by a VDA-induced increase in cell proliferation in the viable tumour tissue. Paclitaxel given 72 h after ZD6126 yielded the best response (50% tumours regressing). A single treatment with ZD6126 followed by weekly administration of PTX was sufficient to achieve a similar response (57% remissions). These findings show that schedule, sequence and timing are crucial in determining the antitumour efficacy of PTX in combination with ZD6126. Induction of tumour necrosis and increased proliferation in the remaining viable tumour tissue could be exploited as readouts to optimise schedules and maximise therapeutic efficacy.

Changes in doxorubicin distribution and toxicity in mice pretreated with the cyclosporin analogue SDZ PSC 833

SDZ PSC 833 (PSC 833) is a cyclosporin A analogue that is under clinical investigation in combination with doxorubicin (Dx) or other anticancer agents as a type-1 multidrug resistance (MDR-1)-reversing agent. The present study was focused on the effects of PSC 833 on the distribution and toxicity of Dx in non-tumor-bearing CDF1 male mice. Mice were given PSC 833 i.p. at 30 min before i.v. Dx treatment. Dx levels were determined by a high-performance liquid chromatography (HPLC) assay at different times during a 72-h period following Dx treatment in the serum, heart, intestine, liver, kidney, and adrenals of mice. In all tissues, Dx area under the concentrationtime curve (AUC) values were much greater in mice receiving 10 mg/kg Dx in combination with 12.5 or 25 mg/kg PSC 833 than in mice receiving Dx alone. The highest increase in Dx concentrations was found in the intestine, liver, kidney, and adrenals. Lower, albeit significant, differences were found in the heart. PSC 833 did not appear to influence either urinary or fecal Dx elimination or Dx metabolism to a great extent. Doses of PSC 833 devoid of any toxicity potentiated the acute and delayed toxicity of Dx dramatically. The mechanism responsible for this enhanced toxicity has not yet been elucidated but is likely to be related to an increased tissue retention of Dx due to inhibition of the P-glycoprotein (Pgp) pump by PSC 833, as has recently been proposed for cyclosporin A.