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March 1, 2009)
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Fri Feb 27, 2009 6:14am EST
By Tan Ee Lyn
HONG KONG (Reuters)
- Experts on Friday urged governments on Friday to diversify their stockpiles of
drugs and called for more new medicines to fight what could be the world's next
flu pandemic caused by the H5N1 bird flu virus.
Many advanced
countries stock up on oseltamivir and zanamivir, two varieties of the same class
of drugs that stops the H5N1 virus from multiplying.
But oseltamivir has
proven to be largely useless in fighting the H1N1 seasonal human influenza virus
and experts are questioning how well, and how long, the drug would stand up
against the H5N1 virus, should it unleash a pandemic.
"We have been
extremely foolish on our policies of stockpiling drugs. We have been stockpiling
two varieties of the same drug," virologist Robert Webster at the St Jude
Children's Hospital in the
He said the
resistance of the H1N1 virus to oseltamivir was as high as 98 percent worldwide.
"The likely
scenario is that the (H5N1) virus will become resistant when you start using
more and more (of one) drug, you get resistant (H5N1) mutants," he told
Reuters later.
The U.S. Centers
for Disease Control and Prevention said in December 2008 that 49 out of 50 H1N1
virus samples tested were no longer sensitive to oseltamivir, which is made by
Roche AG and Gilead Sciences Inc..
Relenza, known
generically as zanamivir, is made by GlaxoSmithKline under license from
Viruses and
bacteria are sturdy organisms that fight hard to survive and adapt swiftly to
drugs that are used to kill them, quickly becoming resistant to them.
Experts at the
conference said most H1N1 viruses were sensitive to oseltamivir just a few years
ago but learnt to adapt to the drug very quickly.
They warned that
H5N1 could learn to adapt quickly to oseltamivir, just as H1N1 has done, because
both viruses share a similar "N1" protein component.
Scientists in
Experience with
viruses similar to H5N1 suggests that it would best be tackled with a
combination of drugs, Webster said.
"Studies with
HIV, leukemia have shown that we have to use multiple drugs," he said. He
suggested that oseltamivir and zanamivir be trialled alongside other drugs like
ribavirin and the adamantane class of drugs, like amantadine and rimantadine.
Malik Peiris a
microbiologist with the
(Editing by Valerie
Lee)
AFP - Thursday, February 26
PARIS (AFP) - - A worldwide team of scientists said the
human immunodeficiency virus (HIV) was swiftly evolving to avoid the body's
immune defences, a phenomenon that adds to the challenge of crafting an AIDS
vaccine.
Mutations in HIV enable it to rapidly
sidestep genetic variations that offer a better natural shield against the
deadly pathogen, they said in a study released by the journal Nature.
"Even in the short time that HIV has
been in the human population, it is doing an effective job of evading our best
efforts at natural immune control of the virus," said Oxford University
researcher Philip Goulder.
"This is high-speed evolution that
we're seeing in the space of just a couple of decades."
Goulder's team analysed the genetic codes
and viral strain of 2,800 infected people in North America, the Caribbean,
Europe, sub-Saharan Africa, Australia and Japan.
Their big focus was on so-called human
leukocyte antigen (HLA) genes.
These control specialised proteins whose job
is to act as a signaller against intruders. The proteins present little pieces
of HIV to the body's heavy armour, T cells, which then seek out the virus and
kill it.
Since HIV was identified as the cause of
AIDS, more than a quarter of a century ago, doctors have learnt that even though
no-one appears to be naturally immune to the virus, people progress to the
full-blown disease at different rates.
Without antiretroviral drugs, some
individuals may develop AIDS as little as a year after infection, while others
take as long as two decades.
The span depends largely on inherited luck,
for there are variants of HLA genes that are far better at combatting HIV than
others. A tiny difference in DNA can make a huge difference in holding back the
virus.
Goulder's team came across some bad news.
They found that the virus is able to mutate
when facing the more successful variants of these genes.
This "escape mutation" is then
transmitted on to the viral progeny and then handed on to the human population
when another person becomes infected.
"Where a favourable HLA gene is present
at high levels in a given population, we see high levels of the mutation that
enable HIV to resist this particular gene effect," said co-author Rodney
Phillips in a press release issued by Oxford University.
"The virus is outrunning human
variation, you might say."
The study adds a further complexity in the
quest for an HIV vaccine, say the authors.
Vaccine engineers will have to wrestle with
different "escape mutations" in HIV that exist in distinct pools of
populations.
For instance, a highly favourable variant of
HLA is called HLA-B*51. It is common among people in Japan -- and, as a result,
two-thirds of infected people there have a strain of HIV which features the
"escape mutation" for this variant.
In Britain and Africa, though, HLA-B*51 is
far less common. As a result, only between 15 to 25 percent of HIV-infected
people have the "escape mutation" in their version of the virus.
So it means that a successful HIV vaccine
may have to take these geographical differences into account, as well as the
stealthy, slippery mutability of the virus itself.
"The implication is that once we have
found an effective vaccine, it would need to be changed on a frequent basis to
catch up with the evolving virus, much like we do today with the flu
vaccine," said Goulder.
AIDS first emerged in 1981 as a novel
disease that destroys immune cells, exposing the body to opportunistic
infections. HIV was identified as its source in 1983. Twenty-five million people
have died of AIDS and an estimated 33 million people have HIV.
The new paper focuses only on HIV's ability
to sidestep natural immune systems. It did not address the virus' mutability
towards anti-HIV drugs.
Reuters - Thursday, February 26
MUMBAI,
Feb 26 - Matrix Laboratories Ltd said it got approval from the World Health
Organisation for generic version of a drug to treat the human immuno-deficiency
virus .
The
WHO approval enables Matrix to market Lopinavir or Ritonavir tablets in dosages
of 200 mg or 50 mg in most countries outside the
The
tablets are the generic version of Abott Laboratories' Kaltera tablets, it
added.
Tue Feb 24, 2009 4:20pm EST
Within 60 days of
release from prison, just 30 percent of HIV-infected inmates in the Texas
Department of Criminal Justice system filled a prescription for antiretroviral
drug therapy, researchers report in Wednesday's issue of the Journal of the
American Medical Association.
Moreover, 90
percent or more of inmates did not fill a prescription soon enough to avoid an
interruption in their antiretroviral therapy, according to the report.
"These
remarkably high rates of lengthy HIV treatment interruptions are troublesome
from a public health perspective," study investigator Dr. Jacques
Baillargeon, from the
"Several
studies suggest that many released inmates who discontinue antiretroviral
therapy also resume high-risk behaviors such as injection drug use or unsafe
sex," Baillargeon added, "and this combination may result not only in
poor clinical outcomes for these individuals but also in the creation of
drug-resistant HIV reservoirs in the general community."
The study involved
2115 HIV-infected inmates who were receiving antiretroviral therapy prior to
their release from prison between January 2004 and December 2007.
Just 5.4 percent of
inmates filled an antiretroviral prescription within 10 days of release, the
researchers found.
Hispanic and
African American inmates were 60 percent less likely than white inmates to fill
a prescription within 10 days, and 30 percent less likely to do so within 30
days.
"Adequately
addressing a public health crisis of this scale and complexity will require
carefully coordinated efforts between academic institutions, the criminal
justice system, and public health agencies," the researchers conclude.
SOURCE: Journal of
the American Medical Association, February 25, 2009.
Wednesday
February 25, 2009, 2:38 pm EST
Mylan
said the WHO's prequalification program approved a generic version of Abbott
Laboratories' drug Kaletra, which is sold in the developing world as Aluvia. The
drug is designed to be heat-stable and low-cost, making it more practical to
distribute and use in countries with warm climates. The approval clears the way
for marketing the drug in many countries outside the
The
generic tablet combines the drugs lopinavair and ritonavir. It is being made by
Matrix Laboratories Ltd. of
Abbott
reported $378 million in Kaletra revenue in 2008.