Saving the best for last? IL-2 last drug mentioned in this article from today.
New generation cancer drugs target carefully
Updated 4:25 PM ET May 23, 2000
By Maggie Fox, Health and Science Correspondent
NEW ORLEANS (Reuters) - The newest generation of experimental cancer drugs are specialists that seek out carefully chosen targets with impressive accuracy, researchers and doctors said on Tuesday.
They described a number of new approaches that are in early trials that might eventually help doctors tailor treatment for individual patients.
Researchers are fond of saying that cancer is not one disease, but a hundred different diseases. And the new drugs being developed attack specific aspects of each disease.
Dr. Nicholas Vogelzang of the University of Chicago said cancer cells "choose" from among 20 or so different proteins to help them survive and spread. These include vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), transforming growth factor (TGF) and others.
Companies and private researchers have chosen a variety of of these targets themselves and Vogelzang said a number of them described at this week's meeting of the American Society of Clinical Oncology (ASCO) looked promising.
AstraZeneca has a drug called ZD1839 or Iressa. Taken as a once daily tablet -- a huge advantage for a cancer drug -- it is targeted against tumors that use a molecule called the epidermal growth factor receptor (EGFR) to survive and spread.
Dr. David Ferry of the Cancer Research Institute in Birmingham, England said he found encouraging results in 16 patients with lung cancer. "It was actually able not only to cause arrest of growth but it caused anti-tumor effects and tumor shrinkage," Ferry told reporters.
The results are very early but some of the patients said they had an easier time breathing and seemed to need less pain control, although Ferry stressed he had not objectively measured this.
"What we see in patients with colon cancer and ovarian cancer is stable disease at four months and some clinical palliation," Ferry said.
Genentech is testing a monoclonal antibody -- a kind of guided missile -- against VEGF. It has helped patients with advanced lung cancer and colon cancer live longer, but they reported a dangerous bleeding in the lungs that killed four of their patients.
Sugen's SU-5416 also works against VEGF, but in a different manner. Colon cancer patients who got the drug with standard chemotherapy saw a 55 percent reduction in the growth of their tumors.
The company said it is too early to tell if the drug helps patients live longer but it has started a Phase III trial, meant to show how well the drug works.
Dr. James Bonner of the University of Alabama at Birmingham tested Imclone's IMC-225, which works against the epidermal growth factor receptor (EGFR), along with radiation therapy in patients with advanced head and neck cancer that could not be removed surgically.
Normally only 35 to 40 percent of such patients have a complete response -- total shrinkage of their tumors -- after radiation therapy.
Adding IMC-225 really helped, Bonner said. His team tested only 15 patients, but all their tumors seemed to have shrunk.
"All of these patients had major responses to treatment," he said. There were 13 complete responses, meaning the tumor shrank completely, and 2 partial responses, meaning the tumor shrank by at least 50 percent.
"It's very good data but it's a small trial," Vogelzang commented. "Is it a breakthrough trial? No."
Dr. Jeffrey Weber of the University of Southern California tried using an immune system molecule to boost the effects of an experimental cancer vaccine.
He used interleukin-2 (IL-2), a signaling chemical known to help rev up the immune system. It was given to 48 patients with advanced melanoma, along with peptides, little pieces of proteins, from the surfaces of their cancer cells.
The idea is to help the body's immune system recognize the tumor cells and destroy them.
"Our population was at an enormous risk of relapse," Weber said. He has not been able to tell if the patients live longer yet, but said it was clear the IL-2 did improve the way their immune systems responded, and said a few patients had a boosted immune response a year or two later.
"It appears this is relatively long-lived," he said.
The American Cancer Society says 1.2 million Americans will be diagnosed with cancer this year and 550,000 will die of it.
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