Originally created 08/30/98

New cancer therapy promising 083098 - The Augusta Chronicle



WASHINGTON -- Amy Applebaum knew she was dying: Cancer that doctors thought they had removed from her breast had roared back and spread to her liver in the same way the disease had killed her sister.

A bad gene fueled the cancer. So Applebaum turned to an experimental treatment called Herceptin, which attacks cancer at its genetic roots -- and 18 months later, the Los Angeles attorney remains healthy and in the courtroom, her four liver tumors shrunk to mere dots.

In a potentially major advance, government doctors decide Wednesday whether to recommend that Herceptin be sold to thousands of American women. It marks the first in a wave of treatments that promise the gene-based attack on cancer without chemotherapy's horrible side effects.

"It heralds a new age in how we're going to treat cancer, with better understanding ... and targeted therapies," said Dr. Dennis Slamon of the Jonsson Cancer Center at the University of California, Los Angeles, whose genetic research led to Herceptin.

Herceptin does not cure breast cancer. It is only for the 30 percent of patients with a defective gene called HER2neu that makes their cancer especially aggressive. Nor is Herceptin a magic bullet for those women. It was tested in advanced patients expected to die within months, and helped only half.

But adding Herceptin to chemotherapy or Taxol worked much better than that standard treatment alone, more than doubling the chances that tumors would be dramatically shrink in women like Applebaum. And weekly infusions of Herceptin alone cut in half tumors in 16 percent of women who already had failed every other drug.

A year later, 12 percent more patients taking Herceptin are alive than those on standard therapy, Slamon said.

How big a difference Herceptin will make remains to be seen, cautions Dr. Michael Friedman, a cancer specialist and the Food and Drug Administration's acting commissioner. Friedman will decide Herceptin's fate by November.

"Will this be an important step or an incremental, little step? We don't know," Friedman said. "Is it worthwhile? Yes. But what the long-term significance of the product is, I don't know."

On Wednesday, the FDA's scientific advisers will consider those questions in recommending whether the government should approve Herceptin and for whom. Women would have to be carefully tested for the HER2 defect, and even the largely nontoxic Herceptin can cause a serious side effect -- heart damage -- if taken with another cancer drug called Adriamycin.

But cautions aside, Herceptin is important because it shows how 20 years of basic cancer research are beginning to pay off for patients, essentially targeting one of many defects that can turn a cell into cancer and fixing it.

"We've been scratching our heads and saying, 'Great, people are winning Nobel prizes, but what about the patients?"' said Dr. Susan Hellman of Genentech Inc., which makes Herceptin.

In the late 1970s, scientists first discovered oncogenes, including HER2neu -- genes that can cause cancer by letting cells grow out of control. At that point, no one knew how to battle them.

Fast forward 10 years. Slamon was hunting a better alternative to chemotherapy, where "in essence you throw a bomb and hope to kill more bad cells than good cells."

He tested different types of tumors for genetic defects. A surprising 30 percent of breast tumors turned out to have too many copies of the HER2/neu gene.

In a healthy cell, HER2 produces a protein that helps signal cells to normally grow and multiply. Slamon proved that if women have too much HER2, their breast cells reproduce out of control and spread through the body. Thus blocking excess HER2 might also block cancer growth.

Enter Genentech. Scientists at the San Francisco biotechnology company cloned antibodies from mice to do just that. Then they "humanized" the antibodies, so women's immune systems wouldn't reject them. Herceptin resulted.

Doctors still don't know exactly how Herceptin works, cautioned Dr. Mario Sznol of the National Cancer Institute. Nor do they understand why if Herceptin inhibits HER2 it fails in so many women with the problem genes. Studies are under way to find out.

Still, nothing in recent years has shown such a strong effect in advanced breast cancer, Sznol acknowledged.

And drugs that help advanced cancer usually work better in early cancer, something else about to be studied. Slamon predicts that soon, a woman's first biopsy will come with an HER2 test so doctors can offer Herceptin before cancer spreads.

He also hopes to test Herceptin against ovarian cancer. New studies suggest those tumors also contain extra HER2.

In the end, this approach may not cure cancer, but regular infusions could let patients live by keeping it under control.

Take Ginger Empey, who failed every cancer drug and should have died by Christmas 1995. Once a week for three years, she has driven a 220-mile round trip to UCLA from her Bakersfield, Calif., home for Herceptin infusions. The three large tumors in her liver now are barely visible specks.

"I am a very healthy patient who's living with cancer, ... and I'm going to be living with it for a long time, I hope," said the 54-year-old grandmother.



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