If you read the study, this study focuses on those who have failed conventional treatment, as is the case with most Phase I trials.
These poor folks have no other choice but to pursue experimental therapy - otherwise their expected survival rate is MUCH less than
what would occur in the normal population.
In addition, Phase I trials are NOT designed to measure efficacy - they are designed to measure safety. Phase II & III trials will be
able to determine prospectively efficacy of treatment versus control.
The effectiveness of chlorotoxin in treatment of glioblastomas was discovered by a scientist here at my institution (http://www.neurobiology.uab.edu/Faculty/Sontheime r/Sontheimer.htm). Glioblastoma is hypothesized to be so deadly because of the
ability of cancer cells inside the brain to quickly migrate from the primary site to other sites within the brain, quickly invading normal
brain tissue. This makes surgery or radiation not very effective, since migrating cells may be hidden within normal brain that is not
irradiated or cut out. The migratory ability of glioblastoma cells is related to its unique ability to change size and morphology to
move in between normal brain cells.
The size-changing migratory ability is related to a specific chloride ion channel that expresses highly and uniquely on certain brain cancer
cells, including gliomas (PubMed ID: 8804043, 8967454). Chlorotoxin, a chloride channel inhibitor discovered in 1993 (PubMed ID: 8383429) was more interestingly found to
bind to this glioma-specific chloride ion channel in mice in 1998 (PubMed ID: 9809993) and humans in 2002 (PubMed ID: 12112367).
Although it was shown that chlorotoxin failed to inhibit migratory ability due to size-change, chlorotoxin was shown to inhibit migration
by inhibition of another protein involved in breaking down the extracellular matrix, allowing cells to more easily migrate.
The strategy that TransMolecular uses to treat gliomas lies in the specificity of expression of the channel to which chlorotoxin binds. That
channel is expressed on the vast majority of glioma tissue samples tested, and only rarely on normal tissue. If one attaches a weak or
short-lasting radioactive moiety to chlorotoxin, a potential treatment can be to target glioma cells using chlorotoxin, and then kill them
by short-lasting localized radiation. This strategy is already being used in Non Hodgkins Lymphoma and other diseases by attaching to tumor-
targeting antibodies a radioactive iodine atom.
PEG is already used in a number of treatments as "PEGylation". PEGylation, or the addition of the polyethylene glycol group, to interferons are already being tried as therapy for Hepatitis C. The advantage lies in the ability of the pegylated compound to resist excretion in the kidneys and to increase solubility.
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If you read the study, this study focuses on those who have failed conventional treatment, as is the case with most Phase I trials.
These poor folks have no other choice but to pursue experimental therapy - otherwise their expected survival rate is MUCH less than what would occur in the normal population.
In addition, Phase I trials are NOT designed to measure efficacy - they are designed to measure safety. Phase II & III trials will be able to determine prospectively efficacy of treatment versus control.
Howdy,
e r/Sontheimer.htm). Glioblastoma is hypothesized to be so deadly because of the
ability of cancer cells inside the brain to quickly migrate from the primary site to other sites within the brain, quickly invading normal
brain tissue. This makes surgery or radiation not very effective, since migrating cells may be hidden within normal brain that is not
irradiated or cut out. The migratory ability of glioblastoma cells is related to its unique ability to change size and morphology to
move in between normal brain cells.
The effectiveness of chlorotoxin in treatment of glioblastomas was discovered by a scientist here at my institution (http://www.neurobiology.uab.edu/Faculty/Sontheim
The size-changing migratory ability is related to a specific chloride ion channel that expresses highly and uniquely on certain brain cancer cells, including gliomas (PubMed ID: 8804043, 8967454). Chlorotoxin, a chloride channel inhibitor discovered in 1993 (PubMed ID: 8383429) was more interestingly found to bind to this glioma-specific chloride ion channel in mice in 1998 (PubMed ID: 9809993) and humans in 2002 (PubMed ID: 12112367). Although it was shown that chlorotoxin failed to inhibit migratory ability due to size-change, chlorotoxin was shown to inhibit migration by inhibition of another protein involved in breaking down the extracellular matrix, allowing cells to more easily migrate.
The strategy that TransMolecular uses to treat gliomas lies in the specificity of expression of the channel to which chlorotoxin binds. That channel is expressed on the vast majority of glioma tissue samples tested, and only rarely on normal tissue. If one attaches a weak or short-lasting radioactive moiety to chlorotoxin, a potential treatment can be to target glioma cells using chlorotoxin, and then kill them by short-lasting localized radiation. This strategy is already being used in Non Hodgkins Lymphoma and other diseases by attaching to tumor- targeting antibodies a radioactive iodine atom.
PEG is already used in a number of treatments as "PEGylation". PEGylation, or the addition of the polyethylene glycol group, to interferons are already being tried as therapy for Hepatitis C. The advantage lies in the ability of the pegylated compound to resist excretion in the kidneys and to increase solubility.