American Home, Merck, Others Step Up Cancer Drug Research
Bloomberg News
May 16, 1999, 9:54 p.m. ET
American Home, Merck, Others Step Up Cancer Drug Research
Atlanta, May 16 (Bloomberg) - Drugmakers including American
Home Products Corp., Schering-Plough Corp. and Merck & Co., are
honing in on the workings of cancer cells in their hunt for new
medicines, hoping to imitate the recent successes of much smaller
biotechnology companies.
Some of the world's largest pharmaceutical companies are
working to make more efficient and safer cancer drugs using
knowledge gained in the past 25 years about the workings of
cells.
Genentech Inc. already has done this with its breakthrough
breast-cancer drug Herceptin, introduced last year. Useful in
about three of 10 breast-cancer cases, Herceptin targets
specifically a protein found on cancer cells. Older cancer drugs
killed any cell in the process of division, hitting all fast-
growing tissues, healthy or cancerous.
''Now, every company is taking the philosophy of saying,
'Let's take a look at the biochemistry of cancer and come up with
a way to interfere with the cells that is patentable,' '' said
Derek Raghavan, a cancer specialist and professor of medicine at
the University of Southern California.
Genentech's Herceptin studies last year stole the show at
the American Society of Clinical Oncology's annual meeting, one
of the world's largest gathering of doctors who specialize in
cancer. This year's meeting drew about 20,000 specialists to
Atlanta.
At this gathering, hundreds of studies presented this week
at the meeting detailed new efforts to stop cancer using recent
advances in biology.
Like Genentech, drugmakers are trying to mimic one of the
body's best natural weapons against disease, antibodies.
American Home, maker of the world's best selling estrogen
replacement therapy Premarin and the painkiller Advil, has
developed an experimental drug that uses a special antibody to
seek out certain leukemia cells. The antibody is attached to a
cancer drug. After the antibody attaches to the cancer cells, the
drug is absorbed. This is a more precise approach than the older
drugs, which blasted all dividing cells.
''It would be great if leukemia cells carried a flag like a
pirate ship,'' said Eric Sievers, a researcher at Fred Hutchinson
Cancer Research Center in Seattle. ''Leukemia cells are really
good at evading our immune system and flying under the radar.''
In a 59-patient study, this experimental drug caused no
damage to the kidneys, heart or central nervous system. Patients
did not suffer hair loss or mouth ulcers, common side effects of
older cancer drugs.
It's too soon to say whether this drug, which American Home
is studying with U.K. biotechnology company Celltech Plc, works
as well as standard chemotherapy, Sievers said. Research
completed so far, though, does indicate the drug works without
the harsh side effects of older drugs.
''What's exciting is that this drug is putting people into
remission more gently,'' Sievers said.
Merck & Co., Johnson & Johnson and Schering-Plough,
meanwhile, are testing drugs that would interfere with a gene
that plays a role in tumor growth, Raghavan said.
About 30 percent of cancers are linked to mutations of the
gene, according to research Merck presented.
The Ultimate Goal
Other studies highlighted today at the medical conference
looked at new ways of fighting cancer, such as gene therapy, and
anti-angiogenesis.
Angiogenesis, the rapid generation of blood vessels, is
essential to fetal development but plays only a small role in a
normal healthy adult. It is key to cancer growth, and by shutting
off angiogenesis, doctors hope to starve tumors without causing
significant damage to healthy tissues.
Researchers today presented data from a study of a drug made
by closely-held Cytran where patients with the AIDS-related skin
cancer Kaposi's Sarcoma took nose drops containing an anti-
angiogenesis protein. More than 30 percent of patients in the
trial had their skin lesions shrunk by the nose drops, and the
main side effects were limited to headaches and fatigue,
researchers said.
The treatment could one day mean offer a way for patients to
control their cancer indefinitely, researchers said.
''That is really the ultimate goal, to make cancer something
more like diabetes,'' where careful management can control the
disease, said Gill Parkash, a doctor from the University of
Southern California School of Medicine, who presented the trials
results today.
Cytran's compound is being studied for melanoma and ovarian
cancer as well, he said.
And researchers from MD Anderson Cancer Center this morning
said they had been able to use gene therapy to inject a ''suicide
gene'' into prostate cancer tumors. Injecting the P53 gene
triggered higher levels of production of a protein which programs
cells to die.
The researchers said they saw evidence that the added levels
of protein induced by the gene injections may have led to tumor
shrinkage, but said that further study is needed to see if that
is the case. The research was sponsored by closely-held Introgen
Therapeutics Inc. and No. 1 French drugmaker Rhone-Poulenc.
Proof of Concept
Researchers also are studying why cancer cells remain in an
immature state, which lets them grow rampant.
Led by George Demetri of Harvard Medical School, researchers
there used Rezulin, a Sankyo Co. diabetes drug sold by Warner-
Lambert Co., to see how it could cause maturation of a rare
condition, cancer of the fat cells. In a study of 60 patients,
Rezulin use did not cause tumors to shrink. The drug, though, did
seem to have some effect on causing the tumor cells to
differentiate and mature.
Still, people should not look at Rezulin as a means of
fighting cancer, Demetri said. ''Proof of concept in oncology
doesn't mean that everyone in the country should start getting
Rezulin,'' Demetri said. |
