BOSTON (The Boston Globe) - An experimental drug has all but vanquished a previously untreatable form of stomach cancer in a test patient and has shown remarkable effectiveness against a lethal blood cancer, according to studies.

The drug, called ST571 or Glivec, was hailed as a "genuine breakthrough" by cancer researchers. Dozens of patients continue to take it and studies to measure its long-term effectiveness against certain cancers continue.

Wednesday, the focus centered on a 55-year-old Finnish woman whose incurable stomach cancer had spread like a brushfire through her abdomen. Every time a growth was surgically removed, several would erupt in its place. Her frustrated doctors at Helsinki University concluded she was beyond the reach of chemotherapy and radiation.

In desperation, they contacted Dr. George DeMetri at the Dana-Farber Cancer Institute here, an expert on the woman's rare type of cancer, called Gastrointestinal Stromal Tumor, or GIST. He knew that Glivec in the laboratory could block a cancer-causing signal that goes awry in GIST tumors. He urged the Helsinki doctors to try it.

The Finnish doctors began e-mailing the results. "I remember sitting at my (computer) screen and saying, "This is a new era,"' DeMetri recalled.

Within two weeks the tumors began to shrink. A report in the current New England Journal of Medicine says the Finnish woman is in good health, living a normal life despite having a cancer that previously was always lethal. And compared to most chemotherapy drugs, this one proved remarkably gentle.

Glivec comes in yellow pills taken by mouth. The woman continues to take it to keep the cancer in check.

The Finnish oncologist in charge of the case, Dr. Heikki Joensuu, said in a telephone interview that the drug reduced the tumor by half in only a month.

"It was very surprising," he said. "We were all very impressed."

In addition to the report on the Finnish woman are two studies on Phase I clinical trial results for Glivec on chronic myeloid leukemia (CML), an often-fatal blood cancer where white blood cells enter proliferate uncontrollably.

The drug was a success when given in high doses to 54 patients in the early stage of CML. In 53 of them, the white cell blood counts decreased markedly or became normal. Many patients continue to take the drug but because they've only been followed for a year or two, there's no hard evidence that they are living longer than patients with conventional treatment. That treatment often includes a bone marrow or stem cell transplant.

Glivec is made by Novartis Oncology of East Hanover, N.J., and was specifically designed to block an errant chemical signal that tells normal white blood cells to reproduce without end. It is not the same signal that causes the GIST tumors.

Dr. Brian Druker, a researcher at Oregon Health Sciences University and lead author on two of the studies in the New England Journal, approached the drug company several years ago about designing a drug to block the protein signal in CML cells. This protein becomes activated when two chromosomes in white blood cells break and exchange fragments. The protein that results from the fracture is called BRC-ABL, and it is the sole cause of CML. Most cancers have multiple causes but some, like CML, have only one - giving researchers a clear target.

Glivec blocks BRC-ABL without harming normal cells. "In theory this is telling us that as we identify each of the key genetic events for various cancers we ought to be able to come up with agents that target those key abnormalities and make big impact on the disease," said Dr. Richard Kaplan, acting chief of clinical investigations at the National Cancer Institute.

Robert Keefe, 68, of Durham, N.C., is a patient at Massachusetts General Hospital enrolled in the Glivec trial. In May 2000, his doctors found a 17-centimeter tumor, shaped like a football. Soon it spread to his liver.

It was inoperable, and doctors ruled out chemotherapy and surgery. Keefe's concerns turned to his four sons.

"It was awful," he said

But eventually he enrolled in the Glivec trial at Mass. General and began taking the four yellow pills every day.

Within a month he noticed results. One day, his doctor, noticing the progress, simply exclaimed "phenomenal" aloud six times.

"We were very lucky to have gotten into this trial ... nothing short of a miracle," said Keefe, who continues his Gilvec treatment.

Copyright 2001 The Boston Globe. All rights reserved.