Untitled Essay, Research Paper
The AIDS virus is one of the most deadly and most wide spread diseases in
the modern era. The disease was first found in 1981 as doctors around the
United States began to report groups of young, homosexual men developing
a rare pneumonia caused by an organism called Penumocystis carini. These
patients then went on to develop many other new and rare complications that
had previously been seen only in patients with severely damaged immune systems.
The Center for Disease Control in the United States named this new epidemic
the acquired immunodeficiency syndrome and defined it by a specific set of
symptoms. In 1983, researchers finally identified the virus that caused AIDS.
They named the virus the human immunodeficiency virus, or HIV. AIDS causes
the immune system of the infected patient to become much less efficient until
it stops working altogether. The first drug that was approved
by the American Food and Drug administration for use in treating the AIDS
virus is called AZT, which stands for azido-thymidine. AZT was released under
the brand name of Retrovir and it’s chemical name is Zidovudine, or ZDV.
The structural name of AZT is 3′-azido-3′- deoxythymidine. AZT works by
inhibiting the process of copying DNA in cells. More specifically, AZT, inhibits
the reverse transcriptase enzyme, which is involved in the DNA replication
process. When DNA is replicating in a cell, there is a specific enzyme that
works along one side of the original DNA strand as the DNA is split into
two strands, copying each individual nucleotide. This enzyme is only able
to work in one direction along the nucleotide string, therefore a different
enzyme, or rather a series of different enzymes is required to work in the
opposite direction. Reverse transcriptase is one of the enzymes that is required
to work in the opposite direction. AZT works by bonding to the reverse
transcriptase enzyme, thereby making it unable to bond with the nucleotide
string and making it unable to fulfill it’s role. This whole process is used
by the HIV virus to replicate itself so that it can continue to infect more
cells. AZT was originally developed over 20 years ago
for the treatment of lukemia. The concept behind this was that the AZT was
supposed to terminate the DNA synthesis in the growing lukemia lymphocytes,
thereby stopping the disease. AZT was rejected at this point because it failed
to lengthen the lives of test animals. The problem with
the AZT drug is that it is not perfect. First of all, AZT will not bond to
each and every reverse transcriptase enzyme in the body, and therefore it
cannot shut down the HIV production completely. The reason for this is because
to put enough AZT in the patient to completely shut down the HIV production
would probably kill the patient. The second, and most serious problem with
AZT is that it also goes into normal, healthy cells and will inhibit their
reverse transcriptase enzyme and will therefore inhibit their ability to
produce new, healthy cells. However, AZT does have an ability to specifically
target HIV infected cells to a certain degree so that it does not kill each
and every cell it gets into. However, it does kill a high proportion of the
cells that it gets into, thereby giving it a high toxicity level.
The formula for AZT is C H N O . The molar mass of AZT
is 267.24 grams per mole. AZT’s melting point is between 106 C and 112 C.
AZT is soluble in water, which is important so that it may dissolve into
the human blood and be distributed to the cells. AZT is usually taken in
a pill format, but it is absorbed by the skin, which can make it dangerous
for people handling the drug. There is quite a bit of
controversy about the effectiveness of AZT. Most experts agree that AZT delays
the progression of HIV disease; the drug may also prolong the disease-free
survival period. However, many doctors still disagree with using AZT as a
treatment for AIDS. Peter Duesberg, a professor of molecular biology at the
university of California, Berkley, says that “In view of this, [the cytotoxicity
level of AZT] there is no rational explanation of how AZT could be beneficial
to AIDS patients, even if HIV were proven to cause AIDS.” This comment stems
from the fact that AZT has a very high cytotoxicity level, which means that
while it kills the infected cells, it will also kill perfectly healthy cells.
According to Dr. Duesberg, AZT will kill approximately nine hundred and ninety
nine healthy cells for each infected cell that it kills. Most of this opposition
to AZT stems from the fact that the initial testing for the drug had severe
problems associated with it. These initial tests were performed with two
groups of AIDS patients. The volunteering patients were secretly divided
into two groups using a double-blind system, where neither the patients nor
the doctors are aware of who is in the placebo, or control group, and who
is in the AZT group. These tests were performed by the FDA at twelve medical
centers throughout the United States. The study actually became unblinded
almost immediately as some patients discovered a difference in taste between
the placebo and AZT caplets and other patients took the capsules to chemists
to have them analyzed. The doctors found out the differences between AZT
patients and the placebo patients by very obvious differences in blood profiles.
An FDA meeting was convened and the decision was made to keep all of the
useless data, and therefore the bad data was thrown in with the good data
and it ended up making all of the data virtually useless. In fact, according
to some sources, AZT ended up shortening the lifespans of many of the patients
taking it. AZT is also thought to be a possible carcinogen, although it has
not been around long enough for any conclusive results to be obtained. After
AZT was approved for use, mortality statistics were taken, they showed a
mortality rate of 10% after 17 weeks, with the original number of patients
being 4805. The FDA tests, with their skewed statistics, showed only a 1%
mortality rate. AZT also had some strange side-effects that were reported
with it’s use, such as raising the IQs of 21 children who took the drug by
15 points, 5 of the children died. The newest treatments
with AZT are combining AZT with other drugs, such as ddI. These tests were
being performed, once again in the double-blind format, just like the original
FDA tests. Three different groups were tested, ones taking only AZT, ones
taking only ddI and ones taking a combination of both ddI and AZT. The Data
Safety Monitoring Board (DSMB), and organization that monitors all testing
in the United States secretly unblinded the test, as they do with all
double-blind tests, and found that the AZT patients had a much higher mortality
rate than those in the straight ddI and the ddI and AZT tests. The DSMB found
the difference in the tests to be high enough to stop the trials early.
In August of 1994, the FDA approved AZT for use by pregnant,
AIDS infected women. Once again it was conducted in a double-blind method
and was placebo controlled. The therapy was begun 14-34 weeks after pregnancy.
However, in this testing it was found that in the AZT mothers, the AIDS
transmission rate to the babies was about 8.3% while the placebo group was
about 25.5%. Therefore the AZT was reducing the AIDS transmission by two
thirds. It is still not clear as to the effectiveness
of AZT to stop or hinder the progress of the AIDS virus. Most experts today
consider AZT to be a valid way to treat AIDS and HIV infection, but they
are constantly experimenting with new combinations of different drugs such
as ddI and AZT to try to better treat AIDS patients. The massive administrative
errors in the initial testing have set the AZT research back and have fostered
unlooked for antipathy. As the treatments become more sound and more reliable,
AZT will find it’s place in AIDS treatments. EndNotes Lauritsen, John. Poison
by Prescription – The AZT Story. New York; Asklepios
Publishing, 1990. pg.7. Lauritsen, John. Poison by Prescription – The AZT
Story. New York; Asklepios Publishing, 1990. pg.7.
Lauritsen, John. Poison by Prescription – The AZT Story. New York; Asklepios
Publishing, 1990. pg.23. Lauritsen, John. Poison
by Prescription – The AZT Story. New York; Asklepios
Publishing, 1990. pg.49. Whitmore, Arthur. AZT Approved for Preventing
Maternal-Fetal HIV Transmission. Internet:
http://www.hivpositive.com/f-DrugAdvisories/II- FDA/4.htm.
August 8, 1994. Bibliography Lauritsen, John. Poison by Prescription – The
AZT Story. New York: Asklepios Publishing, 1990.
Pinsky, Laura. Douglas, Paul Harding. Metroka, Craig. The Essential HIV Treatment
Fact Book. New York: Simon & Schuster Inc.,
1992. Kaiser, Jon D. Immune Power – A Comprehensive Treatment Program for
HIV. New York: St.Martin’s Press, 1993. Whitmore,
Arthur. AZT Approved For Preventing Maternal-Fetal HIV Transmission.
Internet:
http://www.hivpositive.com/f-DrugAdvisories/II-FDA/4.htm, August
8, 1994. Whitmore, Arthur. FDA Grants Accelerated
Approval For 3TC With AZT To Treat AIDS. Internet:
http://www.hivpositive.com/f-DrugAdvisories/II-FDA/17.htm,
November 20, 1995. Clark, Martina. AZT: Pediatric
Study Changed. Internet:
http://www.out.org/HIV/AZT_pediatric_study_changed.htm, “W.O.R.L.D. -
A Newsletter about Women & HIV” April 22, 1995.