New Drugs for Cancer

The long development process of lab screening and animal tests is expensive and weeds out most compounds.  Only about 0.1% of potential medicines eventually make it to clinical trials in human subjects.

The reasons most medicines are screened out are many.  Some work to kill malignant cells but are not specific enough for the targets the scientists set for them or are poisonous.  Others are unstable and would break down in any serious clinical use.  Others may work at the cellular level but there is no way to get the medicine to the cells through administration to the body (e.g. oral, IV).

Once medicines make it to clinical trials, most of those are screened out too.  For one reason or another the backers drop development and do not seek to advance the medicine to the next phase.  Reasons include overly severe side effects or too many side effects or ineffectiveness of the medicine.

Future of Chemotherapy

The  drug discovery industry today divides potential new therapeutic compounds into two categories: small molecule and biologics.  Remember when you were in chemistry class and you drew out the structure of molecules?  Any molecule you can draw on a piece of paper is a “small molecule”.  Most medicine are small molecule drugs.  They are often made by chemical synthesis or some are made by fermentation.

Biologics are enormous molecules.  If you know anything about proteins you know they can have thousands of atoms in a molecule.  Biologics are often, but not always proteins.  As therapeutics biologics first appeared in oncology medicine in the 1990s.  Under the categories immunotherapy and monoclonal antibodies, they offer greater specificity and fewer side effects.

Going forward, industry observers anticipate new combinations of existing therapeutic products and new solutions such as cancer vaccines, nucleic-acid therapies, and new antibodies.

New Immunotherapy

In recent years, development of new immunotherapy agents has revolutionized cancer treatment. These drugs induce or potentiate the anti-tumor activity of the immune system.

The immune system identifies tumors and triggers an anti-tumor response. Such response, however, is modulated by stimulatory and inhibitory factors influencing its success. The new immunomodulating agents are based on inhibition of immune system inhibitors and on enhancement of stimulatory factors. The novelty of this approach stems from the fact that the drug targets the host immune cells and not the tumor itself.

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