Wednesday, March 14, 2012

Targeted invention of targeted drugs: the targeted analysis

Probably you know but nowadays everything in drug developing is targeted. To simplify the subject I am referring for definitions to NCI page:

“Targeted cancer therapies are drugs or other substances that block the growth and spread of cancer by interfering with specific molecules involved in tumor growth and progression. Because scientists often call these molecules “molecular targets,” targeted cancer therapies are sometimes called “molecularly targeted drugs,” “molecularly targeted therapies,” or other similar names. By focusing on molecular and cellular changes that are specific to cancer, targeted cancer therapies may be more effective than other types of treatment, including chemotherapy and radiotherapy, and less harmful to normal cells.”
Basically I would agree but the word “targeted” is not very suitable here.  By several reasons.

1.                         A drug can execute its function by acting onto some molecules.  The drug molecule works on the molecular level. It cannot affect a tissue or a body by acting directly on them. No, the drug binds in some way to another molecule and in such a way affect the cell, the tissue and the body.  On my opinion in this context the term “targeted” is senseless. We are not saying that we are using targeted PCs in order to write targeted posts in targeted blogs for any special targeted reasons? Why should we say that we are developing targeted drugs for targeting treatment?

2.                         By using the term “targeted” we make a distinction from drugs which were developed earlier probably by empirical approach without using the “targeted” modern paradigm. But are these old but still very useful and effective drugs less targeted than up-to-date “really”-targeted drugs in terms of their mode of action? Doxorubicin – does it still inhibit topoisomerase? Paclitaxel? How about its ability to affect tubulin depolymerization?

And looking on the list of “targeted” drugs on the same NCI page (and I can see several old-fashioned molecules there!) I have some concerns that probably selectivity of their targeting ability is not the only reason of their sometimes very little efficacy. Otherwise why so rational targeted  approach is so unproductive and we basically do not have satisfactory treatment options for the majority of types of cancer? Why there are no basically targeted treatments which could alone (!) outperform standard non-targeted chemotherapy but work only in combination with non-targeted chemotherapy (of course I mean Avastin!)?

I definitively do not want undermine the ability of targeted approach to generate targeted dividends both scientific and financial but will just state that in order to be successful in a field of drug development we have to find another “targeted” concept – more targeted in terms of efficiency and productivity.

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