Monoclonal antibodies (mAbs) have been used in the treatment of various diseases for over 20 years and combine high specificity with generally low toxicity. Their pharmacokinetic properties differ ...markedly from those of non-antibody-type drugs, and these properties can have important clinical implications. mAbs are administered intravenously, intramuscularly or subcutaneously. Oral administration is precluded by the molecular size, hydrophilicity and gastric degradation of mAbs. Distribution into tissue is slow because of the molecular size of mAbs, and volumes of distribution are generally low. mAbs are metabolized to peptides and amino acids in several tissues, by circulating phagocytic cells or by their target antigen-containing cells. Antibodies and endogenous immunoglobulins are protected from degradation by binding to protective receptors (the neonatal Fc-receptor FcRn), which explains their long elimination half-lives (up to 4 weeks). Population pharmacokinetic analyses have been applied in assessing covariates in the disposition of mAbs. Both linear and nonlinear elimination have been reported for mAbs, which is probably caused by target-mediated disposition. Possible factors influencing elimination of mAbs include the amount of the target antigen, immune reactions to the antibody and patient demographics. Bodyweight and/or body surface area are generally related to clearance of mAbs, but clinical relevance is often low. Metabolic drug-drug interactions are rare for mAbs. Exposure-response relationships have been described for some mAbs. In conclusion, the parenteral administration, slow tissue distribution and long elimination half-life are the most pronounced clinical pharmacokinetic characteristics of mAbs.
Inhibition of poly(adenosine diphosphate ADP–ribose) polymerase (PARP), a key enzyme for the repair of breaks in DNA, can lead to the accumulation of breaks in double-stranded DNA. The BRCA1 and ...BRCA2 proteins help to repair such breaks. In this phase 1 trial, the PARP inhibitor olaparib was shown to lack the severe toxic effects of conventional chemotherapy and to result in objective responses in tumors with a
BRCA
mutation.
In this phase 1 trial, the poly(ADP–ribose) polymerase inhibitor olaparib was shown to lack the severe toxic effects of conventional chemotherapy and to result in objective responses in tumors with a
BRCA
mutation.
Cellular DNA is continually subject to damage, which coordinated pathways act to repair, thereby maintaining genomic integrity and cell survival.
1
–
3
The poly(adenosine diphosphate ADP–ribose) polymerases (PARPs) are a large family of multifunctional enzymes, the most abundant of which is PARP1. It plays a key role in the repair of DNA single-strand breaks through the repair of base excisions.
4
,
5
The inhibition of PARPs leads to the accumulation of DNA single-strand breaks, which can lead to DNA double-strand breaks at replication forks. Normally, these breaks are repaired by means of the error-free homologous-recombination double-stranded DNA repair pathway,
6
key components of . . .
Wee1 is a protein kinase that regulates the G
checkpoint and prevents entry into mitosis in response to DNA damage. Cyclin-dependent kinases (CDK) are a family of 14 serine/threonine protein kinases ...that coordinate the progression through the cell cycle. The Cdc2/cyclin B complex controls the progression from G
into mitosis. There are two mechanisms by which the G
checkpoint is initiated in response to DNA damage: phosphorylation of Cdc25c by CHK1 and of the Wee1 kinase, which phosphorylates Cdc2. Blockade at the G
checkpoint is especially important for p53-mutant cells because these tumors mainly rely on DNA repair at the G
checkpoint. AZD1775 (formerly MK-1775) is a small-molecule, pyrazol-pyrimidine derivative and potent and ATP-competitive specific inhibitor of the Wee1 kinase. Several preclinical and clinical studies demonstrated encouraging antitumor effects with manageable side effects of the combination of Wee1 inhibition and DNA-damaging agents. Promising combination schedules are being investigated at the moment, for example, combining PARP inhibition and Wee1 inhibition. Also, a weekly schedule with carboplatin and AZD1775 warrants investigation aimed at further improving the antitumor effect.
.
There is accumulating evidence for potential benefits of therapeutic drug monitoring (TDM) in the treatment of cancer with tyrosine kinase inhibitors (TKIs). Relationships between exposure and ...response (efficacy/toxicity) have been established for several TKIs. For example, the pharmacokinetic targets for efficacy of imatinib, sunitinib and pazopanib have been defined as trough plasma concentrations (Ctrough) of >1,000, >50 and >20,000 ng/mL for selected indications, respectively. Dose adjustment based on pharmacokinetic targets could therefore increase response rates and duration. Furthermore, with appropriate target concentrations defined, excessive side effects in patients using the current fixed dosing strategy may be prevented. This review provides a practical guideline for TDM for the currently approved TKIs at 28 February 2013. The focus of this article is on the elaboration of exposure and response relationships of TKIs with proposed pharmacokinetic targets, mainly Ctrough, and further on the interpretation of the pharmacokinetic targets with recommendations for dose titrations.
Paclitaxel and docetaxel are active against a range of human cancers. Their antitumor activity is based on stabilization of the microtubule dynamics and thereby disruption of the cell cycle. The ...taxanes are administered as intravenous solutions in a short administration schedule. Distribution of both taxanes is rapid, with large volumes of distribution and significant binding to plasma proteins. The metabolism of paclitaxel is mediated primarily by the P450 cytochrome enzymes CYP2C8 and CYP3A, whereas docetaxel is only metabolized by CYP3A4. The most common toxicities after intravenous administration are neutropenia, hypersensitivity reactions, neurotoxicity, and alopecia. Several new administration forms are in development; albumin-bound paclitaxel (Abraxane) has recently been registered. Oral formulations of taxanes have been developed, and several are now undergoing phase I trials. New formulations might improve efficacy and safety and could be easier to use.
Abstract Pharmacokinetic–pharmacodynamic modeling using non-linear mixed effects modeling (NONMEM) is a powerful yet challenging technique, as the software is generally accessed from the command ...line. A graphical user interface, Piraña, was developed that offers a complete modeling environment for NONMEM, enabling both novice and advanced users to increase efficiency of their workflow. Piraña provides features for the management and creation of model files, the overview of modeling results, creation of run reports and handling of datasets and output tables, and the running of custom R scripts on model output. Through the secure shell (SSH) protocol, Piraña can also be used to connect to Linux clusters (SGE, MOSIX) for distribution of workload. Modeling with NONMEM is computationally burdensome, which may be alleviated by distributing runs to computer clusters. A solution to this problem is offered here, called PCluster. This platform is easy to set up, runs in standard network environments, and can be extended with additional nodes if needed. The cluster supports the modeling toolkit Perl speaks NONMEM (PsN), and can include dedicated or non-dedicated PCs. A daemon script, written in Perl, was designed to run in the background on each node in the cluster, and to manage job distribution. The PCluster can be accessed from Piraña, and both software products have extensively been tested on a large academic network. The software is available under an open-source license.
Abstract 5-Fluorouracil (5-FU) and capecitabine (CAP) are among the most frequently prescribed anticancer drugs. They are inactivated in the liver by the enzyme dihydropyrimidine dehydrogenase (DPD). ...Up to 5% of the population is DPD deficient and these patients have a significantly increased risk of severe and potentially lethal toxicity when treated with regular doses of 5-FU or CAP. DPD is encoded by the gene DPYD and variants in DPYD can lead to a decreased DPD activity. Although prospective DPYD genotyping is a valuable tool to identify patients with DPD deficiency, and thus those at risk for severe and potential life-threatening toxicity, prospective genotyping has not yet been implemented in daily clinical care. Our goal was to present the available evidence in favour of prospective genotyping, including discussion of unjustified worries on cost-effectiveness, and potential underdosing. We conclude that there is convincing evidence to implement prospective DPYD genotyping with an upfront dose adjustment in DPD deficient patients. Immediate benefit in patient care can be expected through decreasing toxicity, while maintaining efficacy.
Despite the fact that pharmacokinetic exposure of kinase inhibitors (KIs) is highly variable and clear relationships exist between exposure and treatment outcomes, fixed dosing is still standard ...practice. This review aims to summarize the available clinical pharmacokinetic and pharmacodynamic data into practical guidelines for individualized dosing of KIs through therapeutic drug monitoring (TDM). Additionally, we provide an overview of prospective TDM trials and discuss the future steps needed for further implementation of TDM of KIs.
Photodynamic Therapy in Oncology Triesscheijn, Martijn; Baas, Paul; Schellens, Jan H. M. ...
The oncologist (Dayton, Ohio),
October 2006, Letnik:
11, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Learning Objectives
After completing this course, the reader will be able to:
Discuss the safety and side effects of PDT.
Identify appropriate indications for PDT.
Explain the choice of PDT over ...other treatment modalities.
Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Photodynamic therapy (PDT) is increasingly being recognized as an attractive, alternative treatment modality for superficial cancer. Treatment consists of two relatively simple procedures: the administration of a photosensitive drug and illumination of the tumor to activate the drug. Efficacy is high for small superficial tumors and, except for temporary skin photosensitization, there are no long‐term side effects if appropriate protocols are followed. Healing occurs with little or no scarring and the procedure can be repeated without cumulative toxicity. Considering the efficacy and lack of long‐term toxicity of PDT, and the fact that the first treatment of cancer with PDT was done more than 100 years ago, one might expect that this treatment had already become an established therapy. However, PDT is currently offered in only a few selected centers, although it is slowly gaining acceptance as an alternative to conventional cancer therapies. Here, we show the developmental steps PDT underwent and summarize the current clinical applications. The data show that, when properly used, PDT is an effective alternative treatment option in oncology.
Abstract Purpose In tumours with wild-type TP53 , the tumour-suppressive function of p53 is frequently inhibited by HDM2. This phase I, dose-escalating study investigated the maximum tolerated dose ...(MTD), safety, pharmacokinetics and pharmacodynamics of SAR405838, an HDM2 inhibitor, in patients with advanced solid tumours ( NCT01636479 ). Methods In dose escalation, patients with any locally advanced/metastatic solid tumour with TP53 mutation prevalence below 40%, or documented as TP53 wild-type, were eligible. In the MTD expansion cohort, only patients with de-differentiated liposarcoma were included. Primary end-points were MTD and efficacy in the MTD expansion cohort. Secondary end-points included safety, pharmacokinetics and pharmacodynamics biomarkers. Results Seventy-four patients were treated with SAR405838 (50–800 mg once daily QD, 800–1800 mg weekly and 1800 mg twice weekly). Two patients treated with SAR405838 400 mg QD had thrombocytopaenia as a dose-limiting toxicity (DLT). The MTD for the QD schedule of SAR405838 was 300 mg QD. No DLTs were observed with the weekly schedule; one patient had a DLT of nausea with the 1800 mg twice-weekly dose. Treatment with SAR405838 was associated with increased plasma MIC-1, reflecting p53 pathway activation. In the de-differentiated liposarcoma MTD cohort, 89% of the patients had HDM2 amplification at baseline and no TP53 mutations were observed; best response was stable disease in 56% and progression-free rate at 3 months was 32%. Conclusion SAR405838 had an acceptable safety profile with limited activity in patients with advanced solid tumours. The MTD of SAR405838 was 300 mg QD; MTD was not reached with the weekly schedule.
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