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- ATLANTA - From nose drops that fight a cancer common in AIDS patients
to tiny radioactive spheres that fight liver tumors while sparing the organ,
new treatments may transform the way cancer is attacked, researchers said
Sunday.
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- They described promising but highly experimental
new ways to attack cancer that organizers of an annual conference of the
American Society of Clinical Oncology (ASCO) described as some of the most
exciting research being presented at the meeting.
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- "This is a bit of visionary stuff,"
Dr. Derek Raghavan, chief of medical oncology at the University of Southern
California, told a news conference.
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- Dr. Parkash Gill and colleagues at USC
combined two newly fashionable approaches to cancer " charging up
the immune system to attack cancerous cells while also starving the tumors
by blocking them from growing blood vessels to feed themselves, a process
called angiogenesis.
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- They used a drug made by Seattle-based
Cytran Inc., a privately held company, called IM862. It combines two amino
acids, the building block of proteins, that block angiogenesis and at the
same time stimulate the immune system.
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- Gill said his team chose to test it on
Kaposi's sarcoma because it is marked by the creation of many blood vessels.
One of the diseases that marks AIDS, Kaposi's sarcoma causes red, raised
lesions on the skin, so it is easy to see and monitor.
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- Because IM862 is such a small molecule
it can be absorbed right through the mucus membranes, so Cytran formulated
it as nose drops. Gill's team gave it to 44 patients at two sites in Los
Angeles and Boston.
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- Thirty-six percent of the patients had
their tumors either disappear or shrink by at least 50 percent, Gill said.
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- "I expect this compound will have
action in other tumors but unless that has been proven you have to have
great caution in making that claim," Gill said.
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- Nose drops are a much more convenient
way to take a drug, he said. The drug might eventually be added to standard
chemotherapy to allow doctors to reduce the dose and possible side effects,
he added.
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- Reducing toxic effects was the goal of
another study done by Guy van Hazel and colleagues at the University of
Western Australia in Perth, who tested tiny radioactive spheres in people
whose colon cancer had spread to the liver.
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- The SIR-Spheres, made by Paragon Medical
Limited, contain radioactive yttrium-90 and were injected into the hepatic
artery, from which liver tumors get 80 percent of their blood. Healthy
liver cells get most of their blood from elsewhere, so the idea was to
hit tumor cells and spare healthy ones.
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- Van Hazel's team took 74 patients and
either gave them standard chemotherapy for liver cancer, or chemotherapy
plus the spheres.
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- Although the effects were modest, they
were encouraging, Van Hazel said. Fourteen percent of the patients who
got the spheres had their tumors shrink as opposed to 9 percent who got
chemotherapy alone.
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- After two years, 39 percent of patients
who got the spheres were still alive, as opposed to 29 percent of patients
given standard therapy. It looks like the people who got spheres might
survive better as more time goes by, Van Hazel said.
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- "This gives us reason to believe
we are on the right track," Raghavan said.
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- Researchers also told of an experiment
that dramatically extends the lives of patients whose cancer has spread
to the liver and which doctors can start using right away.
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- Dr. Nancy Kemeny of Memorial Sloan-Kettering
Cancer Center in New York found that infusing drugs directly into the hepatic
artery had a much stronger effect than the standard approach, which is
to put the drugs into the general circulation.
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- She used a pump made by Reading, Pennsylvania-based
Arrow International, which is surgically implanted into the patients.
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- After two years, 85 percent of the patients
who got the direct liver infusion were alive and in most, 89 percent, the
liver tumors disappeared. This compared to 69 percent of patients who got
only the general treatment.
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- "Generally, most of my patients
don't survive two years," Kemeny said. "For me, a study that
has an 85 percent two-year-survival is very exciting."
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