|
TREATMENT
|
TARGET
|
HOW THEY WORK
|
STATUS
|
|
Anti- angiogenesis Factors
|
Multiple
|
A growing tumor requires plenty of nutrients, and to make sure
it gets them the tumor secretes substances that stimulate the
growth of new blood vessels. A number of agents can block this
process--at least in animals.
|
See chart below
|
|
Anti- metastatic Factors
|
Multiple
|
What kills most cancer patients is not the primary tumor but its
metastatic spread. Scientists have identified a class of enzymes
that enables cancer cells to enter the bloodstream by dissolving
tissue and boring holes through capillary walls. New drugs could
keep cancer cells confined to one spot.
|
Human tests have just begun
|
|
Anti- oncogenic Factors
|
Multiple, including breast, colon, pancreatic and lung
|
Tumors do more than pick up growth factors that circulate in the
bloodstream; they also make them by switching on "oncogenes."
Many cancers, for example, have been found to contain mutations
in the ras oncogene, and companies are racing to develop drugs
that inhibit its growth-promoting activity.
|
Human tests are in early stages
|
|
Chemo- prevention Therapies
|
Breast, head and neck
|
Many breast cancers depend on the female hormone estrogen to
stimulate their growth. Tamoxifen, which acts as an antiestrogen
in the breast, has been shown to prevent the development of this
form of cancer. Preliminary evidence suggests that a newer
compound, raloxifene, may confer a similar benefit without
serious side effects. Compounds know as retinoids, derivatives
of vitamin A, can prevent recurrence of certain head and neck
cancers.
|
Tamoxifen has been approved as a treatment for breast cancer;
raloxifene, as a treatment for osteoporosis
|
|
Gene Therapies
|
Multiple, including breast, ovarian and small-cell lung cancers
|
In tumors, genes that are supposed to serve as checks on runaway
cell growth are often so damaged that they stop functioning.
Scientists hope to correct this problem by engineering viruses
that can "infect" cancerous cells with healthy tumor-suppressor
genes. Preliminary evidence suggests that this approach can
sometimes cause tumors to stop growing and even shrink in size.
|
Testing in humans has just begun
|
|
Chemo- therapy
|
Multiple
|
New, more selective compounds and powerful but less toxic
versions of older drugs are being added to the oncologist's
arsenal. Oral and wafer formulations of injectable drugs have
made the delivery of chemotherapy more convenient for patients.
Enclosing cancer-killing toxins in a protective lipid "envelope"
can increase their effectiveness while sparing normal tissues.
|
In the past two years, the FDA has approved two dozen new
chemotherapy agents
|
|
Monoclonal Antibodies
|
Non-Hodgkin's lymphoma, breast, colon, melanoma
|
Like miniature guided missiles, these biological constructs home
in on specific proteins displayed on the surface of cancer
cells. By blocking strategic sites, monoclonals can interfere
with a tumor's ability to absorb growth factors from the
bloodstream. They can also carry radioactive and chemical toxins
that directly destroy malignant tissue.
|
Rituxan won FDA approval last year; Bexxar and Herceptin could
be on the market within a year
|
|
Radiation Therapies
|
Multiple: often prostate and solid tumors in internal organs;
lymphomas
|
Radiation destroys cancerous cells but can damage healthy ones
as well. Using 3-D computer images and new delivery techniques
like radiation "seed" implants, doctors can aim doses with
microscopic precision, sparing healthy tissue.
|
In use
|
|
Surgical Procedures
|
Multiple
|
Doctors are always looking for ways to make this standard
treatment more effective and less traumatic for the patient--for
example, by removing part rather than all of a breast or
preceding surgery with other treatments. One promising new
technique is lymphatic mapping, in which surgeons use dyes and
radioactive tracers to help them be more selective in removing
nodes.
|
Widely available; the newest procedures are performed at most
large cancer centers
|
|
Vaccines
|
Melanoma, breast, colon, ovarian, pancreatic and many others
|
Malignant growths have a deadly knack for skirting around the
body's immune system. But scientists are finding that by
vaccinating patients with antigens derived from tumors, they can
sometimes goad white blood cells into attacking cancerous tissues.
|
Dozens of vaccines are being tested
|
WHO'S WHO IN ANGIOGENESIS
Dr. Folkman's approach is not the only
one--or the most advanced
|
DRUG
|
WHO'S WORKING ON IT
|
HOW IT WORKS
|
SOURCE
|
STATUS
|
|
Marimastat
|
British Biotechnology and the NCI; blocks the activity of enzymes
|
Needed to build tumor blood vessels; synthesized in the lab
|
Synthesized in the lab
|
Being tested in breast-cancer patients
|
|
SU5416
|
Sugen and UCLA
|
Prevents a tumor blood-vessel growth factor from binding to its
receptor
|
Synthesized in the lab
|
Being tested for safety in patients
|
|
Neovastat
|
Aeterna Laboratories
|
Inhibits activity of enzyme involved in the growth of tumor
blood-vessel cells
|
Derived from cartilage of spiny-dogfish sharks
|
Safety tested for lung, breast, prostate cancer
|
|
Combreta- statin
|
Oxigene
|
Destroys tumor blood-vessel cells
|
Originally derived from African bush willow
|
Human studies to begin this fall
|
| THP-dox
|
University of Texas Southwestern and ILEX Oncology
|
Attaches to blood-vessel cells and delivers toxin to vessels and
tumors
|
Synthesized in the lab
|
Still being studied in animals
|
| Angiostatin and endostatin
|
Children's Hospital and EntreMed
|
Somehow blocks the growth of tumor blood vessels
|
Originally derived from mouse urine
|
First human trials expected within a year
|
|
Tamoxifen
|
Zeneca will evaluate
|
Mechanism unknown; may block growth of tumor blood vessels
|
Synthesized in the lab
|
New trials to block blood vessels may begin shortly
|
|
TNP-470
|
TAP Pharmaceuticals
|
Blocks enzyme that instructs tumor blood-vessel cells to divide
|
Originally derived from a fungus
|
Being tested in patients
|
