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A limiting factor in cancer treatments is that patients
can't tolerate the combination of different drugs that are attempting to kill
the disease. A Boston based biotech company called Cerulean Pharma has
developed a system that will make it easier for doctors to attack tumors by
killing the cells before they can develop resistance to any one compound. The nanoparticle-delivered
drugs have fewer and less severe side effects.
Image Credit:
Planet Tech
The Problem
Oliver Fetzer, the CEO of Cerulean, notes that cancer
cells can develop resistance to individual drugs very quickly. Even within a
tumor, different cells can have different genetic mutations meaning that a drug
that kills cancer cells in one part of a tumor may not work on other cells. The
best solution is to attack the cancer cells with multiple drugs at the same
time, but this is currently a struggle for many patients and doctors.
The Solution
Nanoparticles
developed by Cerulean may be able to achieve the multiple drug attack since
they are too big to get out of blood vessels and into health tissues, but the
right size to get into tumors via the blood vessels that grow around cancer
tissue. This cancer tissue has pores or gaps that aren't found in healthy
tissue. "These nanoparticles find their way into the tumor through the
leaky [blood vessels], so they can't really escape out of your normal
bloodstream in the healthy tissue," says Fetzer.
Once inside the tissue, the nanoparticles slowing break
down and release the drug a little at a time. Current cancer drugs are held
together by polymer meshes or inside of fatty capsule, but the nanoparticles
described are connected by a chemical bond. The breakdown of the chemical bond
is the mechanism which releases the drug. The rate of this release is
controlled by an enzyme in the body and the rate can be adjusted by using
different linkers.
Image Credit:
Cerulean
The Next Step
Cerulean has conducted early clinical
trials of the lead compound. The compound is called Camptothecin, it is a
nanoparticle which contains a drug that is too toxic to be administered on its
own, but as a compound with the nanoparticle it is well tolerated. The patients
in the trial experience fewer and milder side effects than those given the
current standard treatment. Cerulean expects the results from their human
trials of its lead compound in treating lung cancer to be finalized by the end
of 2012. Testing is also being done with that compound on ovarian cancer and a
phase 1 trial will begin soon for patients with kidney cancer.
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