In Vivo Imaging as a Pharmacodynamic Marker

Abstract

Although numerous anticancer drugs are widely used in the clinic, many questions remain about pharmacokinetics, biodistribution, toxicities, and efficacy. Positron emission tomography (PET) using radiolabeled drugs is a promising method to further understand the clinical behavior of anticancer agents. In addition, it may contribute to better guided treatment planning in individual patients with cancer. Among the available anticancer drugs, considerable experience has been gained with radiolabeling taxanes. At present, two radiolabeled taxanes, paclitaxel and docetaxel, are available as PET tracers.

Radiosynthesis and in Vivo Evaluation of [11C]MPC-6827, the First Brain Penetrant Microtubule PET Ligand

“…[ 11 C]Paclitaxel, [ 18 F]fluoropaclitaxel, and [ 11 C]docetaxel are the successful radiotracers reported so far for MT imaging. 23 Of the three tracers, [ 18 F]fluoropaclitaxel and [ 11 C]docetaxel have been assessed in preclinical and clinical studies. Because docetaxel and paclitaxel are well-characterized substrates of efflux transporters (P-gp, MDR1, BCRP), they have little uptake brain and are not suitable for brain imaging.…”

Pharmacokinetic Principles and Their Application to Central Nervous System Tumors

“…Pharmacodynamic effects are generally directly related to drug concentration, but other factors such as receptor density, drug affinity, ligand binding reversibility, residence time, or regulatory factors are also influential. Current methods to determine pharmacodynamic effects generally require tissue for biologic assays, though the emerging field of imaging biomarkers seeks to leverage non-invasive imaging techniques such as positron emission tomography (PET) imaging to enable clinical pharmacodynamic assessment [ 13 , 14 ].…”

“…Third and least invasive, positron emission tomography (PET) imaging allows for quantification of drug concentration in the human body with some spatial resolution. However, in order to use this method, a radiolabeled version of a drug must be developed, which is time- and labor-intensive, and will not be possible for all molecules of interest [ 13 , 14 ]. Lastly, the gold standard but least accessible method is microdialysis.…”

Systems pharmacology approaches for optimization of antiangiogenic therapies: challenges and opportunities

“…Treatment-induced hypoxia stimulates several compensatory biological processes to circumvent continued VEGF inhibition, leading to resistance to therapy ( Harris, 2002 ; Casanovas et al, 2005 ; Drevs et al, 2005 ; Kerbel, 2005 ; Mizukami et al, 2005 ; Hendriksen et al, 2009 ; Casanovas, 2011 ). This excessive pruning also leads to reduced delivery of therapies into the tumor ( Jain, 2005 ; Van der Veldt et al, 2012 ; Van der Veldt and Lammertsma, 2014 ). Tumors have abnormal vasculature, which leads to an abnormal blood supply that produces hypoxic regions in the tumor.…”