Evaluation of pharmacodynamic biomarkers in a Phase 1a trial of dulanermin (rhApo2L/TRAIL) in patients with advanced tumours

Background:

Dulanermin (rhApo2L/TRAIL) induces apoptosis by binding to death receptors DR4 and DR5, leading to caspase activation and subsequent cell death. A Phase1a trial evaluated the safety and tolerability of dulanermin in patients with advanced tumours. One aim was to develop and validate pharmacodynamic biomarkers to monitor dulanermin activity in patient serum.

Methods:

We optimised assays to measure the cell-death markers caspase 3/7, cytokeratin 18 and genomic DNA in serum. Mice bearing Colo205 xenografts were treated with dulanermin and sera were collected and assayed for apoptotic markers. Upon validating these assays, we monitored apoptotic markers in patients who received dulanermin.

Results:

We detected transient increases in apoptotic markers in mouse sera 8–24 h after dulanermin treatment. This increase was dose-dependent and correlated with active caspase 3 detected by IHC in Colo205 tumours. A statistically significant increase in serum caspase 3/7 was detected in cohorts of colorectal and sarcoma patients 24 h after receiving dulanermin dosed above 4 mg kg⁻¹.

Conclusion:

Owing to limited responses in the Phase 1a study, the changes in circulating cell-death markers were not evaluable. Future studies with dulanermin are needed to determine the utility of these assays with respect to providing evidence of activity or predicting overall response.     

Clinical pharmacokinetics of tyrosine kinase inhibitors: focus on pyrimidines, pyridines and pyrroles

Pyrimidine (imatinib, dasatinib, nilotinib and pazopanib), pyridine (sorafenib) and pyrrole (sunitinib) tyrosine kinase inhibitors (TKIs) are multi-targeted TKIs with high activity towards several families of receptor and non-receptor tyrosine kinases involved in angiogenesis, tumour growth and metastatic progression of cancer. These orally administered TKIs have quite diverse characteristics with regard to absorption from the gastrointestinal tract. Absolute bioavailability in humans has been investigated only for imatinib (almost 100%) and pazopanib (14-39%; n?=?3). On the basis of human radioactivity data, dasatinib is considered to be well absorbed after oral administration (19% and 0.1% of the total radioactivity were excreted as unchanged dasatinib in the faeces and urine, respectively). Quite low absolute bioavailability under fasted conditions is assumed for nilotinib (31%), sorafenib (50%) and sunitinib (50%). Imatinib, dasatinib and sunitinib exhibit dose-proportional increases in their area under the plasma concentration-time curve values over their therapeutic dose ranges. Less than dose-proportional increases were observed for nilotinib at doses ≥400?mg/day and for sorafenib and pazopanib at doses ≥800?mg/day. At steady state, the accumulation ratios are 1.5-2.5 (unchanged imatinib), 2.0 (nilotinib once-daily dosing), 3.4 (nilotinib twice-daily dosing), 1.2-4.5 (pazopanib), 5.7-6.4 (sorafenib) and 3.0-4.5 (sunitinib). Concomitant intake of a high-fat meal does not alter exposure to imatinib, dasatinib and sunitinib but leads to considerably increased bioavailability of nilotinib and pazopanib and decreased bioavailability of sorafenib. With the exception of pazopanib, the TKIs described here have large apparent volumes of distribution, exceeding the volume of body water by at least 4-fold. Very low penetration into the central nervous system in humans has been reported for imatinib and dasatinib, but there are currently no published human data for nilotinib, pazopanib, sorafenib or sunitinib. All TKIs that have been described are more than 90% bound to the plasma proteins: α(1)-acid glycoprotein and/or albumin. They are metabolized primarily via cytochrome P450 (CYP) 3A4, the only exception being sorafenib, for which uridine diphosphate glucuronosyltransferase 1A9 is the other main enzyme involved. Active metabolites of imatinib and sunitinib contribute to their antitumour activity. Although some patient demographics have been identified as significant co-factors that partly explain interindividual variability in exposure to TKIs, these findings have not been regarded as sufficient to recommend age-, sex-, bodyweight- or ethnicity-specific dose adjustment. Systemic exposure to imatinib, sorafenib and pazopanib increases in patients with hepatic impairment, and reduction of the initial therapeutic dose is recommended in this subpopulation. The starting dose of imatinib should also be reduced in renally impaired subjects. Because the solubility of dasatinib is pH dependent, co-administration of histamine H(2)-receptor antagonists and proton pump inhibitors with dasatinib should be avoided. With the exception of sorafenib, systemic exposure to TKIs is significantly decreased/increased by co-administration of potent CYP3A4 inducers/inhibitors, and so it is strongly recommended that the TKI dose is adjusted or that such co-administration is avoided. Caution is also recommended for co-administration of CYP3A4 substrates with TKIs, especially for those with a narrow therapeutic index. However, current recommendations with regard to dose adjustment of TKIs need to be validated in clinical studies. Further investigations are needed to explain the large interindividual variability in the pharmacokinetics of these drugs and to assess theclinical relevance of their interaction potential and inhibitory effects on metabolizing enzymes and transporters.     

Arzanol, a prenylated heterodimeric phloroglucinyl pyrone, inhibits eicosanoid biosynthesis and exhibits anti-inflammatory efficacy in vivo

Based on its capacity to inhibit in vitro HIV-1 replication in T cells and the release of pro-inflammatory cytokines in monocytes, the prenylated heterodimeric phloroglucinyl α-pyrone arzanol was identified as the major anti-inflammatory and anti-viral constituent from Helichrysum italicum. We have now investigated the activity of arzanol on the biosynthesis of pro-inflammatory eicosanoids, evaluating its anti-inflammatory efficacy in vitro and in vivo. Arzanol inhibited 5-lipoxygenase (EC 7.13.11.34) activity and related leukotriene formation in neutrophils, as well as the activity of cyclooxygenase (COX)-1 (EC 1.14.99.1) and the formation of COX-2-derived prostaglandin (PG)E₂in vitro (IC₅₀ = 2.3–9 μM). Detailed studies revealed that arzanol primarily inhibits microsomal PGE₂ synthase (mPGES)-1 (EC 5.3.99.3, IC₅₀ = 0.4 μM) rather than COX-2. In fact, arzanol could block COX-2/mPGES-1-mediated PGE₂ biosynthesis in lipopolysaccharide-stimulated human monocytes and human whole blood, but not the concomitant COX-2-derived biosynthesis of thromboxane B₂ or of 6-keto PGF_1α, and the expression of COX-2 or mPGES-1 protein was not affected. Arzanol potently suppressed the inflammatory response of the carrageenan-induced pleurisy in rats (3.6 mg/kg, i.p.), with significantly reduced levels of PGE₂ in the pleural exudates. Taken together, our data show that arzanol potently inhibits the biosynthesis of pro-inflammatory lipid mediators like PGE₂in vitro and in vivo, providing a mechanistic rationale for the anti-inflammatory activity of H. italicum, and a rationale for further pre-clinical evaluation of this novel anti-inflammatory lead.     

Hemodynamic actions of corticotropin-releasing hormone and proopiomelanocortin derivatives in septic patients

Proopiomelanocortin (POMC) derivatives and mRNA of POMC have been detected in cardiomyocytes and vascular smooth muscle cells. Increased plasma levels of POMC derivatives have been found in septic patients during cardiovascular deregulation; therefore, we evaluated whether corticotroph-type (ACTH, β-endorphin, β-lipotropin) or melanotroph-type (α-melanocyte-stimulating hormone and N-acetyl-β-END) POMC derivatives have influences on patients' hemodynamics during sepsis. Seventeen septic patients were monitored by pulmonary artery catheter and corticotropin-releasing hormone (CRH) tests were performed by intravenous administration of 100 μg CRH. Before, 15, 30, 45, and 60 minutes after CRH administration, hemodynamic variables were measured, and plasma concentrations of POMC derivatives were determined. After CRH administration, heart rate, cardiac index, and stroke index increased, and the systemic vascular resistance index decreased; moreover, a correlation between ACTH concentration and stroke index as well as an inverse correlation between (α-melanocyte-stimulating hormone concentration and systemic vascular resistance index was observed. CRH and ACTH may have opposite effects on the blood pressure (mean arterial pressure). Immediately after CRH injection mean arterial pressure decreased. ACTH (in contrast to β-endorphin or β-lipotropin), released into the cardiovascular compartment 15 minutes after CRH injection, might have raised mean arterial pressure as compatible with the correlation between ACTH levels and stroke index. (α-melanocyte-stimulating hormone appears to have a vasodilative effect during sepsis.     

GM1 gangliosidosis and Morquio B disease: expression analysis of missense mutations affecting the catalytic site of acid β‐galactosidase

Alterations in GLB1, the gene coding for acid β‐D‐galactosidase (β‐Gal), can result in GM1 gangliosidosis (GM1), a neurodegenerative disorder, or in Morquio B disease (MBD), a phenotype with dysostosis multiplex and normal central nervous system (CNS) function. While most MBD patients carry a common allele, c.817TG>CT (p.W273L), only few of the >100 mutations known in GM1 can be related to a certain phenotype. In 25 multiethnic patients with GM1 or MBD, 11 missense mutations were found as well as one novel insertion and a transversion causing aberrant gene products. Except c.602G>A (p.R201H) and two novel alleles, c.592G>T (p.D198Y) and c.1189C>G (p.P397A), all mutants resulted in significantly reduced β‐Gal activities (<10% of normal) upon expression in COS‐1 cells. Although c.997T>C (p.Y333H) expressed 3% of normal activity, the mutant protein was localized in the lysosomal‐endosomal compartment. A homozygous case presented with late infantile GM1, while a heterozygous, juvenile case carried p.Y333H together with p.R201H. This allele, recently found in homozygous MBD, gives rise to rough endoplasmic reticulum (RER)‐located β‐Gal precursors. Thus, unlike classical MBD, the phenotype of heterozygotes carrying p.R201H may rather be determined by poorly active, properly transported products of the counter allele than by the mislocalized p.R201H precursors. Hum Mutat 30, 1–8, 2009. © 2009 Wiley‐Liss, Inc.     

Efficacy of Emodepside plus Praziquantel Tablets (Profender? Tablets for Dogs) against Mature and Immature Adult Ancylostoma caninum and Uncinaria stenocephala Infections in Dogs

This paper reports the efficacy of a novel flavoured tablet formulation of emodepside plus praziquantel (Profender? tablets for dogs) against mature and immature adult hookworms (Ancylostoma caninum and Uncinaria stenocephala) in dogs. The tablets were used at the minimum recommended dose of 1 mg emodepside and 5 mg praziquantel per kg body weight. Four randomised, blinded and controlled laboratory studies demonstrated >95% efficacy against mature and immature adult stages of U. stenocephala and four randomised, blinded and controlled laboratory studies demonstrated >98% efficacy against mature and immature adult stages of A. caninum. No side effects of the treatment were observed. It is concluded that the emodepside plus praziquantel tablet is an effective and safe treatment against mature and immature hookworms.     

Focal nodular hyperplasia of the liver in longterm survivors of neuroblastoma: How much diagnostic imaging is necessary?

Objectives

Focal nodular hyperplasia of the liver is a tumor-like lesion, uncommon in children, but it has recently been more frequently observed in children treated for malignant diseases, especially neuroblastoma. The aetiology is unclear, the pathogenesis remains controversial. Focal nodular hyperplasia of the liver is suspected to be a sequela of tumor therapy.

Methods

Besides the clinical data we evaluated the imaging modalities needed to diagnose focal nodular hyperplasia of the liver in children with neuroblastoma who have been followed in our institution for more than 5 years.

Results

Out of 60 children six developed focal nodular hyperplasia at a median time of 10.5 years after diagnosis of neuroblastoma and 9.4 years after the end of treatment. The diagnosis of focal nodular hyperplasia was based on imaging criteria which are variable in ultrasonography and specific in MRI. Only one child underwent surgical biopsies to rule out liver metastases.

Conclusions

Longterm survivors of neuroblastoma are at risk of developing focal nodular hyperplasia, especially if they underwent toxic chemotherapy and/or radiotherapy to the liver during initial treatment. The recommended diagnostic imaging tools are ultrasonography for detecting liver lesions and MRI for confirming and characterizing these lesions as focal nodular hyperplasia.