Targeted Vs Chemo - and targeted wins!

[gdpawel]

From what I remember, dopamine receptor antagonists inhibit the class of receptors that binds dopamine, a hormone and neurotransmitter. Dopamine is an emetic and can induce nausea, hence blocking dopamine receptors is another treatment of controlling chemotherapy-induced nausea and vomiting. Domperidone (commercially called Motilium) and metoclopramide (Reglan) are the two main dopamine receptor antagonists used for antiemetic treatment. Here is an excellent review on the pharmacokenetics of dopamine receptor antagonists.

http://www.pharmacorama.com/en/Secti...amines_7_4.php

I know there has been some concern about the potential for significant cardiovascular effects of the newer biologic therapies like the tyrosine kinase inhibitor sunitinib (Sutent). Patients and doctors need to get more information and they need to know the potential side effects down the road (a.k.a. tighter monitoring).

In regards to tyrosine kinase, these are very specific enzymes and therefore specific enzyme inhibitors. Most proteins in the body contain tyrosine. But tyrosine is only phosphorylated by a specific tyrosine kinase. Tyrosine is a very general amino acid. It is present everywhere. There are many, many, many tyrosine kinase inhibitors. The effects of these inhibitors is very specific. Therefore, I would not expect that most of the pharmaceutical tyrosine kinase inhibitors would have any effects at all on the neurotransmitter dopamine.

[gdpawel]

In regards to diagnostics in cancer treatment, some phenotype profiling labs, in addition to testing your tumor against a number of chemotherapeutics, can also test the effectiveness of molecularly targeted agents in treating cancer.

Scientists have come to realize that cancer biology is driven by signaling pathways. Cells speak to each other and the messages they send are interpreted via intracellular pathways known as signal transduction. Picture these pathways as if they were phone lines, linking one cell to another.

Many of these pathways are activated or deactivated by chemical reactions. In some cases, programmed cell death is inhibited when these pathways are disrupted. When the cell does not die, as it should normally, cancer forms.

In recent years, research has lead to the creation of “small molecules” to regulate these chemical reactions. Hundreds of these “targeted" agents are currently in development for cancer treatment.

While some physicians are using genomic or proteomic testing to detect mutations in these pathways, phenotype analysis labs have taken a different approach. Using functional profiling, they measure the end result of pathway activation or deactivation in the individual. They can then predict whether the "individual" cancer patient will "actually" respond to a targeted agent.

To date, their results have exceeded the reported results of those who have based treatment regimens on DNA profiles (Arienti et al. Journal of Translational Medicine 2011, 9:94).